optimize cone crusher

xrf analyzer equipment for sale

Were going to do a quick intro to pXRF and pXRD principles and how they work. Then, were going to focus on pXRF, and work through the products, some of the suggested operating procedures, and then spend a bit of time looking at good references, case studies, and applications.

Were have complete geoscience solution; we have diffraction, which can gives us quantitative minerology. So if were looking at this slide, on the top left we can actually derive the amount of minerals so they can quantify them. We have X-ray fluorescence, which is chemistry. We get very good, almost lab grade results if were doing the right job. And then, we also have the ability to look at structural properties of geo sites as well through microscopy, or optical minerology, or petrology, which is again, the backbone of what we learn at university when were looking at minerology. Its the gold standard in a lot of ways.

Breaking it down to the products. And again, today were just going to focus on the portable products. This is our XRF products. Again, chemistry. We have the new VANTA Series handheld, which Ill explain a little bit in the next section. We have the DELTA, which has been the workforce for a good six or seven years now. Many people are familiar with our DELTA Series handheld. And then, Im just going to mention we have some portable bench-tops, some sort of customized smaller systems, as well as our process, and online, and sorting systems as well. If youd like more information about the other products, feel free to get in contact with us after the webinar.

And the one slide which Ive got for microscopy is that we have a bunch of solutions from stereo microscopes to the polarizing microscopes and the metallurgical microscopes, which are all around optical mineralogy. Again, if you need more information, we can point you to the product managers and the specialists in the microscope business.

With XRF and XRD, as you wouldve read in the webinar intro, this talk is essentially targeting people whove got an existent background in the physics. So, Ill keep it quite simple. But again, if you need more information about how the fundamentals work, we can provide you with that. X-ray fluorescence, we shot an X-ray on the sample, we use a technique called EDS, so its Energy Dispersive XRF, where were basically able to get characteristic X-ray back for each element. We measure them in a spectre, we quantify them, and thats what we use to get a quantitative result for each element. Diffractions collect different. Were basically getting the shinning and x-Ray on a sample, were looking at diffraction of the mineral layers within each compound. Theyre all crystal structure. And we end with a diagnostic fingerprint for each mineral. And then, again, we can quantify that using processing techniques.

Many of you know the periodic table continues to give better coverage and better sensitivity. Weve looked at this many times over the years. And essentially, what were looking at in the grain is elements that we can get down to low PPM levels. So with modern X-Ray tubes and with silicon drift detectors, we can now do a really good job across pretty much the whole periodic table. And especially the light elements. The new systems give us the ability to things like magnesium, aluminum, silicon, to labels that weve not been able to do before.

And if we start to look at the market now, we play work different parts of industry. We call it the Mining Value Chain. We start with geoscience research, with geological surveys, we then move to mineral exploration, where were developing around existing operations. We then move into the grade control area where weve got systems trying to make real-time decisions around materials and destination of materials. From there, were able to use that to form the processing division of the business around geometallurgy and aspects of decision-making on chemistry and minerology. And then, at the very backend of the business, we can also play a role in mine closure, and in the environmental business around looking at solar irradiation and contaminated land. Theres one separate business, which we have a nice sort of segue way into, which is around maintenance. A lot of our tools we use for NDT, and for Alloy, and PMI, and things like oil. And again, if youd like more information on that, which Im not going to cover today, we can point you in the right direction.

To dial it down a little bit, and to focus on XRF in particular and this is where Id like to just quickly talk about our new offering. In September, weve released our fifth generation handheld called VANTA. Its a complete revolution in the industry. Its ten plus years of, basically, building an instrument thats been specifically designed for our market. And when I say that, the core pillars are around ruggedization. So we now have IP67 rating, dust and water proof, we have very high temperature ratings, up to 50 degrees C for geocycle. And one of the cool things that will detect a shadow, the mechanical eye lid that come down and protect the detector. We also revolutionary XRF technology, which is all about better accuracy, better precision, and higher cap rates, which means we can do more work faster, with higher accuracy and higher precision. And in the productivity space, we have a whole bunch of new cool stuff coming around cloud-enabled data processing, we have things like embedded GPS, new software its a revolution in handheld XRF.

The products aside, where weve really established ourselves as, essentially, the industry leaders is We all know that XRF can do a great job, but theres a bunch of things that we need to do. And its very similar to what the lab has to do when they process our samples, its all around best practice. We put out a blog, and we had a week called Geoscience Week where we put out a guide called A Quickstart Guide for Best Practices in Portable XRF.

So, we look at the start. We need to start with designing an orientation survey. A lot of that is around standard operating procedure, chain of custody, QA/QC, all things that as geologists were very comfortable dealing with our normal lab regime. This paper that was published and I was a co-publisher, it was a cornerstone paper, which goes to each one of these procedures, around each part of the procedure. Selecting a sample. Preparation what do we want to look at around sample preparation? Data handling, data custody. And then, what do we actually want to do with the data when were finished.

And the next slide is all about selecting what sample. What are we working with? Are we working with bio-geochemical samples? Are we working with soils? Are we working around a drill rig where were taking precaution, or where we actually want to look at drill quill? So, we have to make a decision about the way were going to analyze that sample, and then move forward with the process.

And this slide encompasses a few of the really key aspects. Probably the main one, in the top right corner, is grainsize. And we know that if we have homogenous good materials, were going to get a good result. But if were analyzing course grain materials, were going to get very erratic and heterogeneous results. Similarly, if were running through bags, were going to get attenuation thats obviously going to affect the calibration, its going to dilute our results. So were able to do that, but we need to make sure sap specific calibration is built up to take care of all of those things. And on the left, its an example of how to actually select the right type of soil to get out a sample. Were looking at a soil horizon here, with different parts of the stratigraphy to leave different types of metal due to things like redox and chemical reactions going on in the ground itself. Were actually able to use portable XRF to tell us what sample has the accumulation of metals, and which sample is going to get us the best results.

As the manufacturer, we do the best job we can to give you guys a robust calibration out of the box. We do have lots of different standards, and lots of different samples, but at the end of the day, you want to make sure that youll qualify an instrument, and youre doing the right thing around looking at the performance of the XRF versus certified reference materials. Theres an example of a company, very well-known with research in Australia, who have very good standards that we can after. And this shows portable XRF versus them. Its iron, in this particular case. And if were doing the right thing, we get the same result. So, its very encouraging.

And this is XRF instrument which you can go and buy off the shelf. Theres some pricing there. This is the packaging. You get a nice little portable XRF standards package you can take out into the field for any sampling regime.

The next step in the process that were really very comfortable and very used to doing, is coming on site, and developing site-specific standards. Were working with site-specific standards because the final refinement, or the final tuning or tweaking call it what you will is actually tailoring the XRF to do the absolute perfect job for the type of rocks that youre working with. And what we can see in the bottom left hand corner here is a set of 45 or 47 samples for a very low range metal. In this particular example, its copper and iron in an IOCG deposit. And we built a calibration, and basically, tweaked the calibration so wed get a one to one rating and a 99% correlation to make sure that youre very confident that the analyzer is doing the right job.

As I mentioned earlier, one of the critical points with portable XRF is around sample presentation. And again, we have a whole lot of solutions and a whole lot of expertise around providing that guidance, and providing recommendations on what sort of tools and equipment we can use in the field. Again, if youd like more information, we can certainly point you into the right direction with some of these companies, whether itd be drilling a hole in a sample, or taking a sample right through lead-based, you know, a ring mill or a jewel crusher to get 95% of your sample passing 75 micron. The more that we get towards that, the better results we can achieve in the field.

And if we just want to spend a few seconds focusing just of field-based sampling solutions, theres some fairly well-known bits of equipment out there which you can go and purchase, including this rock grinder for sample either across a wall or a phase underground, or theres this small hammer mill up on the right hand side, which we can use for crushing things like RC chips or soil thats not quite homogenous enough in the field. And you can take these out in the field, run them off 12 volt system off a car. And you can quite easily obtain lab grade results in the field.

And then, more of the Complete Solution level. We have a company that we work in tandem with around creating and developing a full solution. And thats crushing and grinding. We have a sample press. A sample press enables to create a puck without a consumable, it doesnt require a window, which means that youre getting a lot better XRF performance without having attenuation. They also have systems, which flows in the laboratory. Its a laboratory information management system, which manages the chain of custody, the standards, it merges the real-time QA/QC actually while youre running the sample. So, it gives you confidence that youre getting good results whilst youre actually running the samples.

And a key part of what were dealing with is how do we deliver our data in real-time. And anybody who uses the portable XRF knows that we can generate a lot of data very, very quickly. Weve got spreadsheets of multi-element data arriving all over the place. I quite often see people with laptops where theyve got 20 or 30 spreadsheets altogether on the one page, and it gets quite difficult. But having solutions, like this one Ive got up on the screen, the data can arrive into a real-time web portal, it can be QA/QC validated, it can be managed remotely, and then we can get an output, which is designed to be doing exactly what the client would like to see. Roll out of bed in the morning before they go and see the drill rig, and they can see the data on their iPhone, and say, Oh, look, were drilled through the contact, now we need to stop the drill, and make that decision, save lots of money, and then move the drills to the next site. Its all about real-time decision-making.

And then, once we have all that data, its what do we do with it. And as geologists, we generally pass that into a 3D model, we use that 3D model for a lot of things, we use it for mine design, we use it for vectoring towards mineralization, were targeting where were going to drill next. And we have tools, where we have our portable XRF data arrive into a classification system, as in the right hand corner there. The rocks get classified, and then passed straight into a 3D model. So its all about expediting the chain of custody of the data that usually can take months, even up to half a year to get this data into a model and start working with it.

And then, the one small part Im going to talk about a little bit is about how we take that data, and how do we report that data to the market. And again, its been quite controversial in the past, myself and a few others involved around pXRF technologies spent some time with this and said, Well, lets include some of these sampling techniques, some of the recommended procedures when people want to report the data so they can go to table one, we can get some information, and we can get some recommendations on what we need to do to report it. Again, for those whod like more information, weve got lots of good examples with companies who do this the right way, and what you should be looking at to put out in the market.

One of the very well-known industry initiatives that happened a couple of years ago, up here, in Canada, ran by a very well-known geochemist, where we had a bunch of industry companies who sponsored, and we worked through the quality control and assessment of portable XRF. It was all about bench marking. What can XRF do? How can we develop standard operating procedures on variable media? And how can we recommend the best use? Again, thats a great reference, its about 500 pages of reports and data there. And you can go to the its actually on the Association of Applied Geochemists website and download the report. Its a great reference.

And as part of that work, an editor of Geo Magazine, we put together a thematic set. So, two complete issues of Geo which were completely dedicated to portable XRF. And that was where companies and institutions submitted papers on best practices and what theyve done. So, its a great reference out there for those who are looking for papers and for direction on where to head.

An example in Finland, was put together in a special report, which has a whole chapter on portable XRF. And for this particular example, it was looking at Geo chemistry, and how theyre effectively using portable XRF to do that. And in light of that, and actually many years ago, about 15 years ago this is an example of geological survey of Canada with using a similar technique, theyre using litho-geochemistry, so using the chemistry to tell us what part of the stratigraphy and what rock types are in. And what were looking at here, on this downhole plot is the blue data is ICP thats lab data and the red data is XRF, and were getting very agreeable results between the two datasets. And from there, theyre able to work out the rock type, determine the stratigraphy, and basically, adapt and design their drill program in real-time.

Moving forward, an organization that weve worked with a lot in Australia, kind of the coalface and the cutting edge of pXRF technology is that we know the data is very, very good. And when we look at these plots, we can see extremely good agreement between elements. In geoscience, we use certain elements to tell us certain things. We use arsenic as a very string proxy for gold mineralization, we use things like titanium, zirconium, and chrome. They are mobile to mobile element ratios to tell us what are rock types are. And if take that dotted board, were actually able to use that to start to predict and work out what rock types are, and take the subjectivity and some of the fuzziness out of logging rocks. And what were looking at here, its an advanced algorithm its actually called wavelet tessellation where were using iron through a project that was developed through a group which was a large research initiative in Australia. And we can use iron through a wave of tessellation to, basically, break out the rocks and start to break it down into different scales of features that were seeing, you know, first order versus second order versus third order features, and to help that and assist us in breaking up the rock types, which may not be visually obvious for people to pick out in the field.

Moving from the R&D and the geo survey applications, its the first place that we tested XRF and our businesses, generally around soil sampling. So soil sampling works very, very well if fine-grained samples are able to move about on the surface of the earth. And that geochemistry very, very rapidly. And in this particular example, we managed to cover this area, and basically, build up a real-time geochemical map very rapidly. From there, we could move around, we could decide where were we going to go next, and we can use that as a decision-making tool on how were going to change our sample program on the site. One of the really cool things about having assay data right from the field is that you dont just get one element. In the last example we were just saying copper, but now, in this particular example, which is the same dataset, we can see every element side by side. So we have copper, lead, zinc, and we get to see the way the different metals are moving around in the system, and we can see whats mobile and whats not. We can see contamination overprint. For working in an area around the mine, we can see where theres sulfur and sulphides that have been delivered around roads and things like that.

And if we start to talk about the return on investment, and what we ca actually get out of portable XRF, well, the value proposition, the current example I have up on the screen was one of the users in Australia, and it shows what can be achieved with one month with one instrument. And in this particular example, they were able to go out and do very detailed, very fine geochemical sampling over a known area of mineralization its South Australia, around the Burra Copper deposits, which is one of the biggest copper deposits in the world and delineate exactly where they were going to go and drill next. And again, this is several years ago as the technology was emerging. It got the company into the place that they needed to to make those decisions.

As we go further down the value chain, once we have an anomaly, once we have a target, the first thing were going to do is start drilling it. And some of the early drill procedures we might use XRF. In this particular example, were using auger drilling in West Africa. We can see the samples are being brought into a bench-top system. Weve got a small little XRF added in the hood. The samples are being run in a very good chain of custody with great validation. And then, were using that data to classify the rock types, because in that area we cant actually tell what the geology is. Were in an area of residual surface. In this example, we can actually map out the grainstone built amongst the sediments, and then we know where to go and target, because were looking for orogenic gold. So its a very, very powerful tool for delimitating the stratigraphy through what would usually be very difficult to look at.

And sticking on the gold theme, the next example I have up on the screen gives us an example of what the geochemical signatures and what the common pathfinders are that were going to use for going out and looking for gold. And one of the things that Ill state up front and we have for many years is that portable XRF is not very good for gold, but theres a whole host of elements which we can use to go and look for gold, which we call pathfinders. And in this example, at the top here, we can see one of those elements, with ICP versus the same element with portable XRF. And were getting exactly the same map, which means that were very confident that portable XRF is doing the same job.

A little bit of a gold theme here. And thats because the gold business, to us, has been a very effective place where weve, obviously, put a lot of instruments into. And its also an application, weve developed a lot of tools and techniques. This particular paper which I have now on the screen was an example several years ago. A fellow who put together a program at Plutonic Gold Mine to, basically, define stratigraphy and use it for geometallurgical work, which were going to have a look in a couple of slides on the next page.

He was able to, basically, reconstruct the stratigraphic model around Plutonic. Basically, its a sequence of bath salts where the bath salts flow in the basis, so in-between flows the gold deposits along those surfaces and substrates, which in the top corner, the red circles, were looking at chrome versus gold. So, as we step down the stratigraphy, the gold accumulates on the stratigraphic boundaries. Now, when theyre able to do 3D surfaces of that, where they can actually model that, and then use that as a tool for vectoring and for modeling where they think the next gold occurrence is going to be, or look for extensions of the orebody. He was also able to take that data and domain it out in a deposit thats quite difficult. Its a refractory gold deposit, its got high arsenic, its got free milling gold versus refractory gold. Essentially, as the arsenic grade goes up, the recovery drops. So what they were able to do was blend and change the process and technologies so they could optimize recovery based on the material that was being delivered to the mill. And again, its an excellent example of having a dataset which they didnt have the past to drive better recoveries, and to get better results in the mill.

The other cool things weve added in the last few years is the camera and collimator feature. And what they give you the ability to do is actually use the XRF with a focusing mechanism. So, with using the camera, we can collimate down so we can change the size of the zoom to look at a bit smaller things. We can actually use that microstructural assessment. Were looking at grain particular or phase particular work. We have some gold grains in those particular examples, which would be quite difficult to observe by the eye, but with an XRF and a camera, we can do a great job.

Moving on to grade control now, we have an example here of iron ore in Australia where our neo systems have the ability to take something that amounts to a 90-second test, and do it within 15 seconds. So what weve got here is iron, essentially in 90 seconds versus 15 seconds, and against Silicon. This is an example where a lot of elements perform extremely well. And its hard to believe even for myself that we can deliver such good data in such rapid time, which means that you can put a lot of samples through that you may not have been able before, and you can make decisions much faster than youve ever been able to before.

On the second slide, were looking at aluminum and phosphorus. In looking at the deleterious settlements in iron ores. So the last example I have here, its a very hot topic at the moment, the whole lithium factories business is, obviously, very energized at the moment pardon my pun. And its technique where we can actually use portable XRF and XRD together. Because if were looking for lithium, theres a bunch of very cool elements in the periodic table, one being rubidium. It fractions into lithium within the same sort of ratios that we see in lithium. And the other thing that we need to do is look at the minerology. So, we might have a lithium deposit, but it doesnt necessarily mean we can mine it. The XRD is a fantastic tool. Were looking at what phase is it in, were looking at if its spodumene, or if its petalite.

Its been one of the applications weve had a lot of success with. And for those geologists that have worked particularly in various gold deposits, its the hydrothermal fluids, I mean particularly orogenic and epithermal or high solvation systems. They generally have different elements that come along with them. Arsenic is probably the silver bullet. We get very strong association in some orebodies obviously, not all where we can use arsenic in a ratio to give us a ballpark relatively, not always absolute of the gold grade. We have many examples, and many published examples that show how well that can work.

What is X-ray fluorescence and what is XRF? XRF is X-ray fluorescence; thats what it stands for and its a method to get fast, non-destructive elemental information about the sample that you have in front of the analyzer.

What type of samples or applications would you be using XRF? The most common application is for scrap sorting. A scrap dealer gets more money if he knows that his stuff is all the same thing. So when they go to melt it off, they can make new stuff out of that. So, thats really what we do as we say okay, its this grade of metal or that particular grade of metal. And they can sort it into light piles and sell it for more money, and so thats where the value gets added, by knowing what you have.

What other type of applications is XRF being used for? Theres some other metal applications which are for positive material identification which are in oil refineries. You need to know that the pipes that you install there are what theyre supposed to be, so they dont corrode too fast and leak and create a health hazard. But theres a lot more than just metals it can go on to soils for mining or for environmental, if youre looking at like lead in soil and a number of other things like that. Theres consumer products looking to make sure about lead in toys, its even used in archaeometry to look at what paintings are made of, because its non-destructive you can use it on pretty much anything.

Do you have to be highly trained to understand how to use this equipment? No, all the difficult mathematics and all that stuff goes on kind of behind the scenes, so weve made it pretty straightforward to use. With a quick safety training in most regions of the world you can be up and running in a couple of minutes.

Are there any other alternatives to XRF? XRF has kind of a unique space in that it gives you quick answers out in the field because you can take the portable instruments out to your sample. And there are a bunch of laboratory techniques that can be a lot more precise, but those usually involve bringing the sample back to the lab, they require like a lot of digestion and work and sample preparation in the lab, and they also destroy a little bit of the sample. So they have some limitations. Some people would send things into a lab, youre doing this more on location.

How long does it take to do a sample? That really depends on what kind of answer you want to get. For a lot of the scrap sorting, we can get an answer in a second or two in terms of what type of metal it is. Some of the metals are more challenging, it might take 15-20 seconds. In the mining kind of space, theyre looking for usually some very detailed information and the test can take a minute or two. But its again relatively quick compared to the hours of digestion you might have to do in the lab or when you send it off to a lab out, waiting for them to get to it. If you expedite it and pay the extra fees, cause youve got that much time in transit time alone sending it off to a lab. So the immediacy of XRF is really one of the big selling points for it.

All XRF instruments are designed around two major components: a X-ray source, commonly an X-ray tube and a detector. Primary X-rays are generated by the source and directed at the sample surface sometimes passing through a filter to modify the X-ray beam.

When the beam hits the atoms in the sample, they react by generating secondary X-rays that are collected and processed by a detector. Now, lets look at what happens to the atoms in the sample during the analysis. A stable atom is made out of a nucleus and electrons orbiting it. The electrons are arranged in energy levels or shells, and different energy levels can hold different numbers of electrons.

When the high energy primary X-ray collides with an atom, it disturbs its equilibrium. An electron is ejected from a low-energy level and a vacancy is created, making the atom instable. To restore stability, an electron from a higher energy level falls into this vacancy. The excess energy released as the electron moves between the two levels is emitted in the form of a secondary X-ray. The energy of the emitted X-ray is characteristic of the element.

This means that XRF provides qualitative information about the sample measured. However, XRF is also a quantitative technique. The X-rays emitted by the atoms in the sample are collected by a detector and processed in the analyzer to generate a spectrum, showing the X-rays intensity peaks versus their energy. As we have seen, the peak energy identifies the element. Its peak area or intensity gives an indication of its amount in the sample.

The analyzer then uses this information to calculate a samples elemental composition. The whole process from pressing the Start button or trigger, to getting the analysis results can be as quick as two seconds, or it can take several minutes.

Compared to other analytical techniques, XRF has many advantages. Its fast, it measures a wide range of elements and concentrations in many different types of materials, its non-destructive and requires no or very little sample preparation and its very low-cost compared to other techniques. Thats why so many people around the world are using XRF on a daily basis to analyze materials. If you want to find out more about our range of XRF analyzers, please visit our website.

Gold, silver, platinum and their alloys, the gold XRF analyzer can measure them all. The gold analyzer quickly and accurately determines the karatage of gold items, the purity of silver items and any other metals that are in the piece. The gold analyzer was designed with the jewelry industry in mind. Its small footprint wont take up valuable counter space and it can test any piece of jewelry in seconds.

Testing couldnt be easier. Just place, close and tap. The gold XRF analyzer is safe for any user. It can only test samples when the lid is shut, and the flashing light on the top lets you know when the test is actually taking place. Compact, accurate, fast.

Gold XRF testing is completely nondestructive. The sample is not affected or harmed in any way. The gold analyzers viewing window and well-lit chamber allows both operator and customer to see the sample as it is being analyzed.

Karat Mode or the more comprehensive Chemistry Analysis Mode can be selected. The gold analyzer uses X-ray fluorescence, a nondestructive and fast analytical method to test samples. Its easy to use and adapts to nearly any sample size or shape. An integrated camera allows the gold analyzer to focus on and get results from individual components. This is useful when testing pieces that include gemstones.

The gold XRF analyzer offers the convenience of portability as well. An optional battery pack allows testing on the go. The gold analyzer weight only 22 pounds, about 10kg and combined with its custom carrying case can go anywhere you need it to.

webinar : cone crusher optimization what you need to know option 1 - metso outotec

Most quarries and mines are looking to get more out of their producing assets. When it comes to cone crushers, how can you achieve the highest production without pushing your equipment too far, which can result in costly unplanned downtime. To optimize your cone crusher, there are many factors you need to consider such as the crushers closed side setting, cavity level of your crusher, feed distribution characteristics and the level of fines in your process. In this webinar, we take a back to basics look at what factors you should look at and share tips and tricks on optimizing your cone crusher without compromising reliability.

John Starck specializes in the training and education of both end-customers and distributors. A 22-year veteran of the company, John is a subject matter expert on crusher and screen maintenance and operation, with a commitment to customer success. John delivers both an experienced perspective and pertinent solutions to our customer and distributors.

optimizing crusher control | e & mj

At the end of last year, the Australian provider of design, automation, control, instrumentation, electrical engineering and process optimization systems, MIPAC Engineering, announced the award of a significant contract from Germanys Tenova Takraf. MIPAC has been tasked to design and configure the electrical, instrumentation and control for three semi-mobile crushers at a major project in Western Australias Pilbara region.

According to the companys business development director, Alan Thorne, it had been liaising with Tenova Takraf about the project since 2011. MIPACs experience in crusher control systems and other mining operations made us a natural choice to undertake the crusher control design and configuration, he said. The work will be completed by August.

The crusher control system is PLC- and SCADA-based, with MIPAC developing the functional specification for the control philosophy in conjunction with Tenova Takraf. The design involves plans for one crusher that will then be replicated for the other two. This will significantly reduce engineering costs, according to MIPAC project manager, Ashish Mahajan, who said, MIPAC will also be involved in HAZOP studies and machine safety studies conducted by Tenova Takraf as part of the development of the crusher operational philosophy.

This example is just one of a growing body of practice founded on ensuring that crushers run at their most economical setting, while at the same time maintaining consistent throughput. All stages of comminution are energy-hungry, and while energy usage rises in line with the fineness of reduction, a lot can be gained from optimizing each stage of the crushing and grinding process. Hence ensuring that the drive and control systems installed on crushers and mills are doing the job for which they were designed makes strong economic sense.

The Brain in ControlAccording to Sandvik, the intelligent drive and control systems in its CH series of cone crushers and CG series of primary gyratories enable real-time performance management, most tangibly equaling maximized crusher performance and productivity. The company explained that the brain in its crusher control system, the Automatic Setting Regulation system (commonly known as ASRi), protects the crusher from overload and constantly monitors the power draw, the hydroset pressure and the mainshaft position (and thus the closed-side settingCSS) in real time. It adapts the crushers settings in real time to match feed-curve variations as well as variations in feed material hardness, thereby ensuring consistent maximum performance, Sandvik added.

By continuously measuring and automatically compensating for cone crusher liner wear, the ASRi allows customers to fully utilize crusher liners and schedule liner replacements to coincide with scheduled maintenance stops, Sandvik said, while noting that the ASRi also allows quick and easy remote calibration, even from a control room.

The company added that when the Auto-CSS regulation mode is selected, the ASRi aims to maintain the stipulated CSS. Alternatively, in Auto-load mode, the system focuses on keeping the selected set-points for the main motor power consumption and main shaft hydroset pressure, such that the crusher operates at the required load level. If the highest permitted load level is selected, maximum reduction will occur as the CSS will always be the smallest possible.

According to Sandvik, the software package supplied with the ASRi includes an OPC-server that allows seamless integration with superior control systems such as SCADA and DCS systems. This communication provides complete access to all the parameters in the ASRi as well as allowing adjustments to be made remotely during operation.

For customers who do not wish to build their own pictures in SCADA, Sandvik supplies its WINi graphics software option. This can allow a customer to control their ASRi remotely using the same graphical user interface as on the ASRi. Sandvik makes the analogy that it is like installing an extension of ASRi on a PC, so that a control-room operator can independently select pages on WINi without interfering with the operator in the field.

It is also possible to have different settings on WINi than on ASRisuch as language and units. Where an operation has more than one ASRi, the WINi software can be used with up to nine different ASRis, displaying them on an overview picture, so that the user can easily monitor and compare several machines at once.

Sandvik pointed out that automated systems are not just limited to overall crusher control. Proper lubrication will maximize the lifetime of vital crusher components, for instance. All of its CH800 series and CG series crushers are equipped with a Tank Instrumentation Monitoring System (TIMS), which monitors all auxiliaries in the crusher to ensure optimized lubrication. Meanwhile, the lubrication system for its gyratory crushers is designed to be controlled by variable-frequency drives (VFDs), using flow meters to deliver exactly the right flow into the crusher.

Field ExperienceSandvik gave some examples of the benefits that can be gained from using its ASRi control system. In a CG-type primary gyratory, if a big rock becomes jammed in the crusher intake, the ASRi system allows the operator to switch from automatic to manual mode so that the crusher can be opened. This might help to re-orientate the rock sufficiently to enable it to be crushed. The ASRi is then switched back to automatic and the crusher returns to normal operating conditions, with minimal disruption to production.

The company cites an installation at the Teberebie gold mine in Ghana, which used a size 54-74 primary gyratory crusher equipped with ASR+ (an older version of ASRi). Flexible crusher operation was essential as the mine produced three different types of orehard, soft and sandyeach with different crushing characteristics. Each ore type had its own individual operating programs with preset parameters in the ASR+, allowing the operator to select the correct program depending on the ore type. The crusher could then work at the optimal settings so as to best utilize its capabilities, without any risk of overloading.

In a second example, Sandvik describes a case where an operator has several CH870 crushers with ASRi and WINi installed, allowing crushing to be operated from a control room. The same operator also has some bowl-type crushers on site and, the company said, has commented on the difference when calibrating.

As this particular customer is dependent on a certain product size, they run their CH870s on Auto CSS, which automatically learns and compensates for wear. However, Sandvik said, they wanted to be completely sure about the setting. Taking just 30 seconds to complete, the ASRi allows them to calibrate the crusher several times a day to ensure that the product size is indeed correct.

With the bowl-type crushers, the situation is completely different, Sandvik pointed out. The customer needs to go out to the crusher, stop the feed, unclamp the bowl, manually measure the setting and reclamp the bowl, before restarting the feed. As this takes more than 30 minutes, it is only done once a day because of the crusher downtime involved, so the product size is not as consistent.

HPGR Presents Other ChallengesWith high-pressure grinding rolls (HPGR) offering a viable alternative to conventional crushing in appropriate situations, acceptance of this technology is becoming increasingly widespread within mineral production. Yet, as Siemens pointed out, controlling an HPGR installation presents a different set of challenges, particularly in relation to keeping wear at an acceptable level.

The company noted that since HPGR operations have to be designed to perform at optimum efficiency to minimize excessive energy and maintenance costs, its optimized drive systems can help by providing accurate speed and operating torque control. Siemens claimed that by matching the best-suited components at each step from its extensive drive system, motor, gearbox and load-distribution control product portfolios into a completely integrated system, it can ensure that HPGR installations can handle large overloads for long periods.

Siemens noted that one particular area where its control systems are proving invaluable is in torque sharing in HPGR plants. Since there are separate drives to each of the rollers, it is essential to have equal torque sharingif this is not the case, one roller will end up doing more work than the other.

Once this happens, there will be more wear on that particular roller and throughout its drive components, so maintenance and wear-part replacement will increase. However, the other roller will probably still be serviceable then, and will only need maintenance later on, meaning that overall, downtime will be higher and the crusher will be out of action for longer.

Siemens stated that as different sizes of material enter the HPGR rolls, fast torque-to-speed response is critical. Enabling the machine to compensate for load variations allows for more consistent quality, less strain on components, and lower energy consumption. Speed compensation also adjusts for the reduction in the roller diameters resulting from wear on the roller faces.

Siemens said that it uses a proprietary load-sharing technology to ensure that torque is shared accurately to within 1%reducing wear on mechanical components and preventing system overloads. Continuous speed control also reduces process vibration by compensating for variability in the ore feed.

Electrical Drives Bring BenefitsTurning to conventional mining crushers, Siemens noted that the inclusion of an electrical drive at the crushers front end provides benefits such as improved energy efficiency during operation as well as a reduction in the inrush current at startup. Together with smoother control during startup, this in turn helps to reduce any negative impact of crusher operation on the stability of the power network, the company added.

Other benefits include the optimization of the relationship between torque and speed control, which allows the machine better to compensate for variations in the ore characteristics. Accurate speed control also helps maintain consistency in the size of the crushed material, while the use of an effective electrical drive gives the operator improved capabilities to avoid or clear system jams.

As well as this, crusher systems with multiple motors benefit significantly from drive control as mechanical wear caused by torque imbalance is reduced, Siemens said. There is also greater operational flexibility through the use of independent motor control, while maintenance requirements can also be simplified.

Writing in the most recent edition of the companys customer magazine, Results, Metsos Pasi Airikka explained that automation decreases variations due to raw material quality changes, process and machine loads, and external circumstances such as moisture contents and the weather. Consequently, stabilized variations result in better production, quality and plant availability, he said.

A product manager for Metso Automation, Airikka noted that while even the most intelligent process automation system for a crushing and screening process may not outperform the best operator at his bestin the long run, it will prove its worth. Achieving maximum results requires integration of the process, machine, and automation expertise already in the plant engineering and design phase, he stated.

Practical ImplicationsIn a paper presented at MEIs Comminution 2014 conference, held in Cape Town earlier this year, Dr. Erik Hulthn, Magnus Evertsson and colleagues from Chalmers University of Technology and LKAB in Sweden described a study they had undertaken on optimizing cone crusher operation at the Malmberget iron-ore mine. As they pointed out, modern cone crushers are equipped to adjust the closed-side setting automatically to compensate for increasing wear over time. In addition, the use of a frequency converter to adjust the eccentric speed means that this can now be done in real time, without the need to stop the crusher and change drive-belt positions.

The study used a Sandvik CH680 cone crusher that is used to reduce 100-mm feed to minus-30 mm. In summary, the work showed that by selecting the optimum control points for the CSS and speed, the crusher efficiency could be improved significantly. There was also a marked increase in the output of minus-1-mm material, meaning that later, higher energy-use comminution stages would have less work to do. The authors noted that they are now developing a fully automated real-time algorithm, with the aim of consistently maximizing the circuits output.

The product and production development department at Chalmers has a long history of research into rock crushing, with a spin-off company, Roctim, now offering the eYe process optimization system that includes features such as Hulthns real time optimization algorithms.

Roctim has also developed its Crusher Control Unit (CCU) to supervise the crushing process and protect crushers from overload and fatigue damage. The company noted that, at around half the price of major OEM systems, the CCU offers an alternative solution for older crushers that have outlived their original control unit, or have never had one fitted. Various operating settings can be programmed into the units PLC, and the CCU can be operated either via a touch screen or through a site-wide HMI/SCADA system.

Clearly, there are considerable incentives to operate crushers as efficiently as possible, while minimizing the risk of premature wear and failure. Modern drive and control systems have gone a long way to achieving these aims, bringing better energy efficiency and higher, more consistent output to the crushing process.

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optimizing cone crusher performance on clay - crushing, screening & conveying - metallurgist & mineral processing engineer

We have an HP300 crusher in our operations carrying out tertiary crushing duty where it reduces material of P80 - 32mm to P80 - 16mm. The ore feed is kimbelite ore which is resulting in a clayish product build up in the crusher discharged chute and crusher cavity which in the last experience resulted in materiel build in the chute blocking it out and resulted inwearing out the counter weight, the socket and the head bush of the crusher. The crusher is in a closed circuit with a wet screen but we are not adding any water into the crusher its mainly crushing material with surface moisture in the range of 8-12%. The question is there anyone out there who has had such experience with a cone crusher and before making a decision to go to the market and buy a replacement crusher, what remedial actions to optimize performance. We have currently shut of the water on the wet screen and are running the plant in dry mode but it comes with many problem of dust generation, and we go into the wet season the little rain on the ore wil resulting in the screen caking up the reason we intended to move to wet screening but now have revered back to this undesirable state despite its disadvantages.

Clay in a cone crusher - the bane of operators for generations. One option is to look at a rotary scrubber with trommel or a rotary scrubber with a separate vibrating screen, either ahead of the primary crusher, or after the primary crusher (depending on the top size of the material going to the primary crusher). Water is added to the feed end of the scrubber, and can also be added to the vibrating screen. The fines (-8 mm to -10 mm depending on your grinding circuit feed size, can then be pumped directly to the grinding circuit. While these units are not cheap, they allow you to take out all the fines and bypass the entire crushing plant, and "voila" many of your crushing problems go away. The downside is that the fines bypass any weightometers in the crushing plant so you have to estimate these tons by other means in order to complete your metallurgical accounting. If you can give us an estimated feed rate to the crushing plant we (the collective 911 Metallurgical Group) might have some additional ideas for you. Best Regards - Andrew

Hi AJNeale thanks for the feedback, just to clarify a little bit more the feed to the crusher is closed with a screen (the one in wet operation) and the feed to the crusher is between 7-11% passing the CSS of 16mm. we are currently ruuning all proces in dry mode s o that the tertairy does not cake up but once we go into the rainy season which we are in now clogging problems manifest on the screen which we were trying to avoid by wet screen. in dry mode the caking in the HP300 disappears but in the wet season that we are in now the screen cloggs then the materail is all short circuited to the crusher with fines now ( increase in percentage passing CSS of 16mm) resultantly the caking in the crusher resurfaces.

Hello Dzapasi, since the silence is killing me and likely you too, I will take a run at this. I have some experience with high moisture crushing but am nowhere near 'an expert'. This will give you some things to review/consider.

1. Sticky material in crusher feed.2. Fines in crusher feed (smaller than crusher setting) exceeding 10% of crusher capacity.3. Excessive feed moisture.4. Material cleanliness5. Feed segregation in crusher cavity.6. Insufficient scalper and closed circuit screen capacities.

You may want to review your crusher liner shape. A cone crusher concaves may be straight (smooth), modified straight, or non-choking. Curved concaves are useful in crushing rocks containing sticky, moist, or dirty material that may otherwise clog the crusher. The modified straight concaves are a compromise between the straight and the non-choking concave types. These shapes do not affect the crusher capacity very much. These liners were originally designed for high-speed gyratory crushers and may be (or not) adapted to cones?

It is lots and lots of work but you may have to demand more frequent cleanup of places where you know material will stick. Hammers, air lances, long bars or other tools. Have you tried teflon lining of some chutes or sidewalls?

Are you crushing too fast? Do you have spare capacity or wasted operating time during which you could crush slower which would allow you to handle those fines a bit better? What is your current crusher operating time? I have seen plant complaining of wet ore and cone crusher packing while they were only crushing 50% of the time ie: the cone was needlessly being over loaded. The cone was overloaded AND so was the screening deck before the crusher = bad screening = extra fines + extra wets into the cone.

Thanks David have pulled out some pointers and the points above gave me a lot of ideas especially on the screening media we currently use sq polyU panels and comparing with VR they are definety worth a try. On the utilization aspect we aim to run the crusher as much as possible as it has to generate a stockpile for down stream plants so the current problems on the tertiary crusher are resulting in the circuit producing less than downstream capacity. i will forward some photo's on the effects of the clayish material in the crusher crushing cavity and discharge. the liner change out i have forwarded to OEM to confirm if they have such liners to assist with our challenge. thanks once again.

The problem is with the inability of your screen to adequately wash the fines out of your crusher feed, likely combined with poor drainage through the deck beyond the spray zone(s). The most common cause of this that I am aware of is insufficient water application, usually a combination of inadequate volume and inefficient or incomplete spray pattern coverage. There should be several spray applications down the length of the deck starting after the first set of open panels and at least 2 additional applications (spray bars) evenly spaced to about 2/3 to 3/4 of the way down the deck (leave the last 1/4 to 1/3 of the deck for draining water) - there should be alternating spray and drain intervals down the deck to achieve the best wash for minimal water volume. Your crusher feed should contain no more than ~4-5% moisture, provided you can remove the fines that are transporting the excess. To determine the best moisture content you can expect, try wet-screening (washing) a bucket of crusher feed at 12 mm and immediately check the moisture content of the oversize.

If your deck is inclined, consider reducing the angle to slow the flow of material down the deck. Screen panels with "dams" on them as shown in the second photo in David's reply will help spread the material evenly across the deck and also slow it down to help both washing and draining.

On the underside of your mantle, you may be able to attach blades to knock buildup off of the eccentric support arms before it can contact the balance weight or get into your eccentric seal. You may also be able to find (or have cast) eccentric arm liners with steeper angle to better shed buildup. For buildup in the chutes, consider lining the areas that build up with UHMW polyethylene to better shed sticky material.

Thanks Craig the pointer to the water distribution on the screen really open up some avenues of areas we will need to optimize, the pointer to the UHMW polythene has confirmed a liner change idea we were throwing around so thanks for firming up this area.

I have seen a mini cone crusher used on Kimberlite that apparently had a high clay content.In order to avoid the packing build up of compacted fines in the crushing chamber they flushed with copious amounts of water. The water jets directed blades of high pressure water directly on to the mantle. I never saw it in action but from what I heard is worked very effectively.

Have you already considered Alderox or any other release agent applied directly to the crushing surfaces? I used it with success on a Sandvik 4800, crushing ceramic clay. It was also useful in chutes, sidewalls and feeders. One application per shift following 20 minutes of drying time did the job.

this is a first to hear of and would require a little more info. The application per shift was it only in the crusher or the chutes as well. is it like at shift start operator goes around problem areas and apply it. Is it a bulk application process or it quite manageable. when you were crushing ceramic clay what was the feed size to the crusher and its product size. Finally how big/complex is the applicator system, do we buy it from supplier or its a side package.

It could also be applied with a mopper but with lots of waste. The operator sprayed every problematic area at the beginning of the shift and left it to dry while conducting the pre-start check of the crushing plant. As you can see the application is quite simple and straightforward. I remember the country distributor for Alderox (3M at the time) sent me 1 gallon for free to conduct some tests.

The plant was locatedin a very dry region and we only use Alderox during rainy season. It didn't rain too often but as you know clay traps moisture. We didn't applied the product at the end of the shift for fear of overnight rains washing it away.

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what is cone crusher?

Machines have become one of the important parts of our life and without them, we can not expect our life to go smoothly now on. There are many types of machines which we use at home and some others are there which we dont use at home but they too are very important for us. Today in this article we will talk about one such machine that is a cone crusher.

There are many different types of rock crusher used to break the rocks. Cone crusher is one of them. Though the cone crusher can work perfectly also, most of the time people use it along with Jaw crusher which also does almost the same things with few differences. The cone crusher is a very heavy machine which needs to be maintained on a daily basis. The main fields where the cone crusher is used are construction, mining, quarrying, and some others like these fields. With the help of this cone crusher, one can easily get the very fine pieces of rocks. The size of the pieces of Rock which you can expect from this cone crusher ranges somewhere between 35mm to 350 mm.

The whole body of the cone crusher is divided into many parts. Some of those parts are the main parts. Without them, the functioning of the cone crusher cant be expected. The whole body of the machine is fitted on the vertical metallic structure which is also known as the main shaft. This main shaft is attached to another shaft which is known as the countershaft. Both these shafts work in collaboration for the proper functioning of the cone crusher. The countershaft is mainly used to rotate the main shaft with the help of pinions, drive pulley, and electric motor. The mantle is another main part of the cone crusher which is attached at the top of the main shaft. Above the mantle, there is one more part of the cone crusher which is known as concave. The wedge is also an important part of the cone crusher which acts as the breaker for the whole system of the machine.

The working of this machine is very simple. The Mantle and concave together create space between them. First of all the electrical motor is started which in turn rotates the countershaft, main shaft, and the whole system. After this, the big rock pieces are fed into the gaps between the mantle and the concave through inlets. The rock pieces are broken into the smaller pieces inside the crushing chamber with the movement of the main shaft, mantle, and concave. When the size of broken pieces becomes smaller enough, it gets out of the machine through the outlet. It can be collected below the machine very easily.

cone crusher - an overview | sciencedirect topics

Cone crushers were originally designed and developed by Symons around 1920 and therefore are often described as Symons cone crushers. As the mechanisms of crushing in these crushers are similar to gyratory crushers their designs are similar, but in this case the spindle is supported at the bottom of the gyrating cone instead of being suspended as in larger gyratory crushers. Figure5.3 is a schematic diagram of a cone crusher.

The breaking head gyrates inside an inverted truncated cone. These crushers are designed so that the head-to-depth ratio is larger than the standard gyratory crusher and the cone angles are much flatter and the slope of the mantle and the concaves are parallel to each other. The flatter cone angles help to retain the particles longer between the crushing surfaces and therefore produce much finer particles. To prevent damage to the crushing surfaces, the concave or shell of the crushers is held in place by strong springs or hydraulics which yield to permit uncrushable tramp material to pass through.

The secondary crushers are designated as Standard cone crushers having stepped liners and tertiary Short Head cone crushers, which have smoother crushing faces and steeper cone angles of the breaking head. The approximate distance of the annular space at the discharge end designates the size of the cone crushers. A brief summary of the design characteristics is given in Table5.4 for crusher operation in open-circuit and closed-circuit situations.

The Standard cone crushers are for normal use. The Short Head cone crushers are designed for tertiary or quaternary crushing where finer product is required. These crushers are invariably operated in closed circuit. The final product sizes are fine, medium or coarse depending on the closed set spacing, the configuration of the crushing chamber and classifier performance, which is always installed in parallel.

For finer product sizes, i.e., less than 6mm, special cone crushers known as Gyradisc crushers are available. The operation is similar to the standard cone crushers, except that the size reduction is caused more by attrition than by impact [5]. The reduction ratio is around 8:1 and as the product size is relatively small the feed size is limited to less than 50mm with a nip angle between 25 and 30. The Gyradisc crushers have head diameters from around 900 to 2100mm. These crushers are always operated under choke feed conditions. The feed size is less than 50mm and therefore the product size is usually less than 69mm.

Maintenance of the wear components in both gyratory and cone crushers is one of the major operating costs. Wear monitoring is possible using a Faro Arm (Figure 6.10), which is a portable coordinate measurement machine. Ultrasonic profiling is also used. A more advanced system using a laser scanner tool to profile the mantle and concave produces a 3D image of the crushing chamber (Erikson, 2014). Some of the benefits of the liner profiling systems include: improved prediction of mantle and concave liner replacement; identifying asymmetric and high wear areas; measurement of open and closed side settings; and quantifying wear life with competing liner alloys.

Various types of rock fracture occur at different loading rates. For example, rock destruction by a boring machine, a jaw or cone crusher, and a grinding roll machine are within the extent of low loading rates, often called quasistatic loading condition. On the contrary, rock fracture in percussive drilling and blasting happens under high loading rates, usually named dynamic loading condition. This chapter presents loading rate effects on rock strengths, rock fracture toughness, rock fragmentation, energy partitioning, and energy efficiency. Finally, some of engineering applications of loading rate effects are discussed.

In Chapter4, we have already seen the mechanism of crushing in a jaw crusher. Considering it further we can see that when a single particle, marked 1 in Figure11.5a, is nipped between the jaws of a jaw crusher the particle breaks producing fragments, marked 2 and 3 in Figure11.5b. Particles marked 2 are larger than the open set on the crusher and are retained for crushing on the next cycle. Particles of size 3, smaller than the open set of the crusher, can travel down faster and occupy or pass through the lower portion of the crusher while the jaw swings away. In the next cycle the probability of the larger particles (size 2) breaking is greater than the smaller sized particle 3. In the following cycle, therefore, particle size 2 is likely to disappear preferentially and the progeny joins the rest of thesmaller size particles indicated as 3 in Figure11.5c. In the figures, the position of the crushed particles that do not exist after comminution is shaded white (merely to indicate the positions they had occupied before comminution). Particles that have been crushed and travelled down are shown in grey. The figure clearly illustrates the mechanism of crushing and the classification that takes place within the breaking zone during the process, as also illustrated in Figure11.4. This type of breakage process occurs within a jaw crusher, gyratory crusher, roll crusher and rod mills. Equation (11.19) then is a description of the crusher model.

In practice however, instead of a single particle, the feed consists of a combination of particles present in several size fractions. The probability of breakage of some relatively larger sized particles in preference to smaller particles has already been mentioned. For completeness, the curve for the probability of breakage of different particle sizes is again shown in Figure11.6. It can be seen that for particle sizes ranging between 0 K1, the probability of breakage is zero as the particles are too small. Sizes between K1 and K2 are assumed to break according a parabolic curve. Particle sizes greater than K2 would always be broken. According to Whiten [16], this classification function Ci, representing the probability of a particle of size di entering the breakage stage of the crusher, may be expressed as

The classification function can be readily expressed as a lower triangular matrix [1,16] where the elements represent the proportion of particles in each size interval that would break. To construct a mathematical model to relate product and feed sizes where the crusher feed contains a proportion of particles which are smaller than the closed set and hence will pass through the crusher with little or no breakage, Whiten [16] advocated a crusher model as shown in Figure11.7.

The considerations in Figure11.7 are similar to the general model for size reduction illustrated in Figure11.4 except in this case the feed is initially directed to a classifier, which eliminates particle sizes less than K1. The coarse classifier product then enters the crushing zone. Thus, only the crushable larger size material enters the crusher zone. The crusher product iscombined with the main feed and the process repeated. The undersize from the classifier is the product.

While considering the above aspects of a model of crushers, it is important to remember that the size reduction process in commercial operations is continuous over long periods of time. In actual practice, therefore, the same operation is repeated over long periods, so the general expression for product size must take this factor into account. Hence, a parameter v is introduced to represent the number of cycles of operation. As all cycles are assumed identical the general model given in Equation (11.31) should, therefore, be modified as

Multiple vectors B C written in matrix form:BC=0.580000.200.60000.120.180.6100.

Now determine (I B C) and (I C)(IBC)=10.5800000000.210.42000000.1200.12610.27450000.0400.06300.0910=0.420000.20.58000.120.1260.725500.040.0630.091and(IC)=000000.300000.5500001

Now find the values of x1, x2, x3 and x4 as(0.42x1)+(0x2)+(0x3)+(0x4)=10,thereforex1=23.8(0.2x1)+(0.58x2)+(0x3)+(0x4)=33,thereforex2=65.1(0.12x1)+(0.126x2)+(0.7255x3)+(0x4)=32,thereforex3=59.4(0.04x1)+(0.063x2)+(0.09x3)+(1x4)=20,thereforex4=30.4

In this process, mined quartz is crushed into pieces using crushing/smashing equipment. Generally, the quartz smashing plant comprises a jaw smasher, a cone crusher, an impact smasher, a vibrating feeder, a vibrating screen, and a belt conveyor. The vibrating feeder feeds materials to the jaw crusher for essential crushing. At that point, the yielding material from the jaw crusher is moved to a cone crusher for optional crushing, and afterward to effect for the third time crushing. As part of next process, the squashed quartz is moved to a vibrating screen for sieving to various sizes.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

For a particular operation where the ore size is known, it is necessary to estimate the diameter of rolls required for a specific degree of size reduction. To estimate the roll diameter, it is convenient to assume that the particle to be crushed is spherical and roll surfaces are smooth. Figure6.2 shows a spherical particle about to enter the crushing zone of a roll crusher and is about to be nipped. For rolls that have equal radius and length, tangents drawn at the point of contact of the particle and the two rolls meet to form the nip angle (2). From simple geometry it can be seen that for a particle of size d, nipped between two rolls of radius R:

Equation (6.2) indicates that to estimate the radius R of the roll, the nip angle is required. The nip angle on its part will depend on the coefficient of friction, , between the roll surface and the particle surface. To estimate the coefficient of friction, consider a compressive force, F, exerted by the rolls on the particle just prior to crushing, operating normal to the roll surface, at the point of contact, and the frictional force between the roll and particle acting along a tangent to the roll surface at the point of contact. The frictional force is a function of the compressive force F and is given by the expression, F. If we consider the vertical components of these forces, and neglect the force due to gravity, then it can be seen that at the point of contact (Figure6.2) for the particle to be just nipped by the rolls, the equilibrium conditions apply where

As the friction coefficient is roughly between 0.20 and 0.30, the nip angle has a value of about 1117. However, when the rolls are in motion the friction characteristics between the ore particle will depend on the speed of the rolls. According to Wills [6], the speed is related to the kinetic coefficient of friction of the revolving rolls, K, by the relation

Equation (6.4) shows that the K values decrease slightly with increasing speed. For speed changes between 150 and 200rpm and ranging from 0.2 to 0.3, the value of K changes between 0.037 and 0.056. Equation (6.2) can be used to select the size of roll crushers for specific requirements. For nip angles between 11 and 17, Figure6.3 indicates the roll sizes calculated for different maximum feed sizes for a set of 12.5mm.

The maximum particle size of a limestone sample received from a cone crusher was 2.5cm. It was required to further crush it down to 0.5cm in a roll crusher with smooth rolls. The friction coefficient between steel and particles was 0.25, if the rolls were set at 6.3mm and both revolved to crush, estimate the diameter of the rolls.

It is generally observed that rolls can accept particles sizes larger than the calculated diameters and larger nip angles when the rate of entry of feed in crushing zone is comparable with the speed of rotation of the rolls.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

The main task of renovation construction waste handling is the separation of lightweight impurities and construction waste. The rolling crusher with opposite rollers is capable of crushing the brittle debris and compressing the lightweight materials by the low-speed and high-pressure extrusion of the two opposite rollers. As the gap between the opposite rollers, rotation speed, and pressure are all adjustable, materials of different scales in renovation construction waste can be handled.

The concrete C&D waste recycling process of impact crusher+cone crusher+hoop-roller grinder is also capable of handling brick waste. In general, the secondary crushing using the cone crusher in this process with an enclosed crusher is a process of multicrushing, and the water content of waste will become an important affecting factor. The wet waste will be adhered on the wall of the grinding chamber, and the crushing efficiency and waste discharging will be affected. When the climate is humid, only coarse impact crushing is performed and in this case the crushed materials are used for roadbase materials. Otherwise, three consecutive crushings are performed and the recycled coarse aggregate, fine aggregate, and powder materials are collected, respectively.

The brick and concrete C&D waste recycling process of impact crusher+rolling crusher+hoop-roller grinder is also capable of handling the concrete waste. In this case, the water content of waste will not be an important affecting factor. This process is suitable in the regions with wet climates.

The renovation C&D waste recycling process of rolling crusher (coarse/primary crushing)+rolling crusher (intermediate/secondary crushing)+rolling crusher (fine/tertiary crushing) is also capable of handling the two kinds of waste discussed earlier. The particle size of debris is crushed less than 20mm and the lightweight materials are compressed, and they are separated using the drum sieve. The energy consumption is low in this process; however, the shape of products is not good (usually flat and with cracks). There is no problem in roadbase material and raw materials of prefabricated product production. But molders (the rotation of rotors in crusher is used to polish the edge and corner) should be used for premixed concrete and mortar production.

cone crusher, stone crusher manufacturers, suppliers in india

Weve been designing and developing Cone Crusher / Stone Crusher, in close association with customers, for over 10 yrs. We have a lot of cones operating in almost all types of rock. RD group is proud of the knowledge and expertise it has gained from developing cones and is a integral part of our crushing system.

analysis and optimization of cone crusher performance - sciencedirect

Solving practical problems in cone crusher design, the quantity of rock material falling out of the crushing chamber during one eccentric rotation of the cone was analyzed. A simple and practical model for predicting cone crusher output is proposed. Based on previous research a model able to directly calculate the mass percentage of flakiness in the product has been obtained and a method of analysing the variation of the flakiness percentage in the process of crushing is proposed. Taking the output prediction model as an objective function, and the size reduction model and flakiness prediction model as constraints, optimization of the cone crusher has been achieved. The validity of this optimization was verified via full-scale testing. This work will prove useful for developing further cone crusher improvement strategies.

chamber optimization for comprehensive improvement of cone crusher productivity and product quality

Fengbiao Wu, Lifeng Ma, Guanghui Zhao, Zhijian Wang, "Chamber Optimization for Comprehensive Improvement of Cone Crusher Productivity and Product Quality", Mathematical Problems in Engineering, vol. 2021, Article ID 5516813, 13 pages, 2021. https://doi.org/10.1155/2021/5516813

This study aims to analyze the impact of key structural parameters such as the bottom angle of the mantle, the length of the parallel zone, and the eccentric angle on the productivity and product quality of the cone crusher and optimize the crushing chamber to improve the crusher performance. The amount of ore in the blockage layer was calculated by analyzing the movement state of the ore in the crushing chamber. Considering the amount of ore uplift further, the traditional mathematical model of crusher productivity was revised. Then, a mathematical model for dual-objective optimization of productivity and product quality of cone crusher was established. Furthermore, taking the existing C900 cone crusher as the research object, the influence of key parameters on the performance of the crusher was researched. And the optimal values of key structural parameters were obtained. Finally, based on the iron ore coarsely crushed by the gyratory crusher, the dynamic characteristics of the C900 cone crusher were simulated by using the discrete element method (DEM), and the simulation results are basically consistent with the numerical analysis results. Results show that considering the amount of ore uplift in the blockage layer, the revised mathematical model of crusher productivity can better characterize the actual productivity. The bottom angle of the mantle and the length of the parallel zone are within the range of 5060and 140mm190mm, respectively. The productivity shows a positive correlation with the bottom angle and a negative correlation with the length of the parallel zone. But the dependence of product quality on the angle and the length is just the opposite. The eccentric angle is within the range of 1.42 and its decrease has a negative effect on the productivity and product quality.

As one of the key equipment in the bulk materials crushing system, the cone crusher is mainly used for the medium and fine crushing of bulk materials. With the continuous promotion of breaking instead of grinding, the application of cone crusher is more extensive. The crushing chamber is the key factor that determines the performance of the cone crusher. At present, Bengtsson, Grndah, Lee et al. [15], Zhang et al. [6], Huang et al. [7], Khalid et al. [8], Bengtsson et al. [9], and Franks et al. [10] have studied the interparticle breakage behavior of bulk materials through the ore mechanics test system and established a productivity model, and the influence of the engagement angle, different close side settings (CSS), the mantle shaft speed, and particle shape of the cone crusher on the performance of the crusher is studied. However, the productivity model does not consider the effect of ore uplift in the blockage layer, and the bottom angle of the mantle, the length of the parallel zone, and the eccentric angle have a great influence on the chamber structure, and the chamber structure is related to the number of broken ores. Therefore, it is necessary to further study the influence of these parameters on the crushing performance. In addition, the DEM has been proved to be a very good virtual simulation environment by Cleary, Delaney et al. [11, 12], Quist et al. [13], and Chen et al. [14]. The virtual simulation environment can be used to gain a fundamental understanding regarding internal processes and operational responses. A virtual crushing platform can not only be used for understanding but also for the development of new crushers and for optimization purposes.

Therefore, the working process of the cone crusher is taken as the specific analysis object, and considering the amount of ore uplift, the traditional mathematical model of crusher productivity was revised. Then, a mathematical model for dual-objective optimization of productivity and product particle size distribution of cone crusher was established. Furthermore, the influence of the bottom angle of the mantle, the length of the parallel zone, and the eccentric angle on cone crusher performances is analyzed by the optimal numerical calculation method. Finally, the reliability of the optimization model and optimization algorithm of cone crusher is verified by the DEM based on the characteristics of coarse crushing ores.

The crushing chamber is composed of the mantle and concave, as shown in Figures 1(a) and 1(b). The drive turns the horizontal countershaft. The pinion gear on the countershaft rotates the eccentric gear. The eccentric bushing rotation causes the mantle to wobble. The functional principle of a cone crusher is to compress particles between two surfaces. The compressive action is realised by inflicting a nutational motion on the mantle while the concave remains fixed. The ore is squeezed and crushed several times along the crushing chamber from the feeding port to the discharging port, especially in the parallel section, which does the final crushing. Larger ore needs longer time between squeezes.

The crushing of ore is directly related to the compression ratio, and the bottom angle and eccentric angle determine the compression stroke of the mantle. The length of the parallel zone determines the number of ore fractures. Therefore, the productivity and particle quality of the cone crusher are affected by these structural parameters of the crushing chamber.

Productivity refers to the amount of ore processed by the crusher per unit time under the conditions of certain feed size and discharge size, which is a key indicator reflecting the performance of the crusher. The calculation results of the existing cone crusher productivity are compared with the actual production results. The calculation results are always greater than the actual production results. After analysis, because the crusher has a blockage layer in actual work, the mantle far away from the concave will fall. The ore on the side of the mantle close to the concave will arch up and cannot be discharged from the discharge port. Therefore, it is necessary to theoretically derive the amount of ore in the blockage layer and revise the existing theoretical calculation model of cone crusher productivity.

The existing theoretical calculation model of productivity is calculated based on the volume of the ore discharged from the crushing chamber once the mantle swings [15], as shown in Figure 2. The following equation represents the mathematical model:where is the volume of the ore discharged from the crushing chamber once the mantle swings, is the thickness of the ore layer when the ore is compressed, is the ore displacement when the mantle swings, and is the average diameter of the ore compression layer, considered to be approximately equal to the bottom diameter of the mantle [16].

Considering the ore hardness and feed size, the following equation represents the productivity per minute:where is productivity, is ore bulk density, is the mantle swing times per minute, is loose factor, , is ore hardness coefficient (hard ore: ; medium hard or soft ore: ), is feed size factor, and is feed opening width, as shown in Table 1.

As shown in Figure 3, the crushing chamber formed by the mantle and the concave is divided into four areas, and the mantle rotates counterclockwise. When the mantle closes to the concave and extrudes the ore, the ore in the A and D areas will arch upward. That is, when the mantle is close to the concave, the ore cannot be discharged naturally and upward movement occurs.

At this time, the ore speed is consistent with the moving speed of the mantle, and the ore throughput is obtained by double-integrating the ore velocity and area in the A and D areas. In Figure 3, plane is the cross section of the blockage layer, is the center of the concave section, and is the center of the mantle section.

Therefore, the ore quantity in this area is calculated, and then the traditional productivity theory is used to subtract the ore quantity in this part, so a more accurate calculation method of productivity can be obtained. Ore velocity in the upper arch area is shown as follows:where is 1/2 cycle, (the rotating speed of the mantle is ) and is the moving distance of the mantle. Take a microelement for the upper arch area of the blockage layer, and the integral function of the upper arch zone can be expressed as follows:where is the angle enclosed by the upper arch boundary and the coordinate axis, is the distance from the center of the concave to the boundary of the mantle, is the radius of the concave, and is the speed of the ore in the upper arch area.

The good performance of the cone crusher is mainly reflected in the high productivity and neat particle size distribution of crushed products. There is a strong coupling relationship between productivity optimization and product quality optimization models. Based on the principle of interparticle breakage, the kinematic characteristics of bulk materials, and the population balance modeling (PBM), a dual-objective programming model of the cone crusher is established.

In the case of ensuring the particle size of the crushed product, the productivity of the crusher should be improved as much as possible. Taking productivity as the first objective function of optimizing crusher chamber, the objective function as shown in the following equation is obtained according to equation (5):

The mass proportion of the bulk materials whose diameter is smaller than the CSS is the main technical index to measure the particle size distribution of the crushed product. Therefore, the following equation is used as the second objective function for optimizing the chamber shape of the crusher:

Equation (7) is based on the model proposed and perfected by Broadbent et al. [18] and Lynch [19] in the study of coal crushing process. After the continuous improvement of most scholars, equation (8) of the product particle size distribution model of the material is gradually summarized:where is selection function, is crushing function, is the number of crushing times the material has been subjected to, , is the unit matrix of feeding granularity.

For the selection function and crushing function mentioned in the above equation, Professor Evertsson of Chalmers University of Technology in Sweden [20, 21] has obtained the relevant mathematical model by simulating lamination crushing through experiments, as shown in the following equations:where is the compression height of the bulk materials before lamination and crushing, is the amount of feed compression, is the particle size of the Nth layer of the lamination and crushing materials, is the smallest particle size in the product, is the largest particle size in the feed, and is the equivalent particle size of the Nth layer of laminated crushed materials.

The chamber structure parameters of the cone crusher are the key parameters that affect the performance of the crusher. The bottom angle of the mantle , the length of the parallel zone , the eccentric angle , and the rotating speed are determined as the design variables of the dual-objective programming model, as shown in the following equation:

The value range of the crushing optimization constraints was set by referring to the parameters of the C900 cone crusher. The parameters of C900 are shown in Table 2 where is open side size, is eccentricity, and is engagement angle.(1)According to the calculation of the critical speed and the actual parameters r/min, speed was defined as .(2)According to the suspension height of the cone crusher, the eccentric angle was defined as . The swing stroke and eccentricity of the mantle are affected by the eccentric angle.(3)According to the original parameters and actual design experience, the value range of the bottom angle of the mantle was defined as .(4)The product quality can be effectively improved by increasing the length of the parallel zone, and the length of the parallel zone was defined as .

The objective function was determined by studying the performance of the cone crusher. The design variables were determined by analyzing the structure parameters and process parameters of the cone crusher. The constraint conditions were set by combining the parameters of the cone crusher C900. Comprehensive analysis of the objective optimization problem of the cone crusher was performed using the main objective method, taking productivity as the main objective of crusher optimization and transforming the product quality optimization into nonlinear constraints. According to equations (6), (7), (12), and (13), the dual-objective programming model of cone crusher is established, and the forms are shown in the following equations:

The dual-objective programming model of the cone crusher is solved by using K-T [22] nonlinear sequential quadratic programming method, and the optimization results are shown in Table 3. Figures 46 show the effects of changing the bottom angle of the mantle , the length of the parallel zone , and the eccentric angle on productivity and particle size distribution of crushed products.

As shown in Figures 4(a) and 4(b), crusher productivity is increased from 1008t/h to 1238t/h at the rate of 23%, as the bottom angle of the mantle increases from 50 to 60. However, the particle size and quality of crushed products decrease, which is less than the closed side setting of broken product percentage from 85% to 78%. This is due to the decrease of the effective crushing times in the crushing chamber when the bottom angle of the mantle increases.

As shown in Figures 5(a) and 5(b), crusher productivity is decreased from 998t/h to 850t/h at the rate of 15%,, as the length of the parallel zone increases from 140mm to 190mm. However, the particle size and quality of crushed products increase, which is less than the closed side setting of broken product percentage which increases by about 9.6%. This is because as the parallel zone increases, ores were more fully broken, but the broken time results in a decline in productivity growth.

As shown in Figures 6(a) and 6(b), crusher productivity and the particle size and quality are increased, as the eccentric angle increases from 1.4 to 2. This is because the eccentricity of the crusher and swing stroke of the mantle increase with the increase of eccentric angle.

The above research shows that the influence of the structure parameters of the crusher on the productivity and product quality is mutually restricted, and there is a strong coupling relationship. Therefore, both productivity optimization and product quality optimization are taken into account, the optimal performance parameters of the crusher C900 were obtained, the mantle bottom angle is in the range of 50 to 60, the length of the parallel zone is in the range of 140mm190mm, and the eccentric angle is in the range of 1.42. The optimal structural parameters of the C900 crusher chamber was obtained: the swing speed of the mantle, the length of the parallel zone, the bottom angle of the mantle, the eccentric angle, the eccentricity, and the engagement angle are 285r/min, 150mm, 55, 2, 44.8mm, and 23, respectively.

The DEM provides a bonding and energy accumulation crushing model, which can accurately describe the crushing process of ores under the action of equipment. Hasankhoei et al. [23] and Cleary et al. [24] have proved to be a powerful tool for studying the flow of bulk materials and ore crushing behavior. In this paper, based on the coarse broken iron ores in the rotary crusher, the ore particle model was established by using DEM software. The dynamic characteristics of the model were simulated by combining with the three-dimensional cone crusher model in order to study the influence of relevant parameters on the performance of the crusher.

Before the ore modeling with DEM software, the basic physical and mechanical properties of iron ore were explored through rock uniaxial compression [25, 26], fracture toughness, rock material damage, and other experiments. The grain size, structure size, internal porosity, pore radius, coordination number, and other factors of the ore were analyzed by computed tomography (CT) nondestructive testing technology. The DEM virtual ore model can more truly reflect the physical characteristics and crushing characteristics from the experimental results. Figure 7 shows the cutting and sampling from the crude ore after the rotary crusher. The equipment used is a cutting machine and a drilling prototype to make the iron ore into regular cylindrical specimens for the mechanical properties experiment.

For the collected specimens, the internal structure and characteristics of the ore were observed through nondestructive testing with CT. The internal structure of the ore is visually characterized through three-dimensional technology [27, 28]. Finally, the relationship between structure and performance was established based on the experimental data. Figures 8(a) and 8(b) show the technical scheme of CT nondestructive testing and CT.

The test conditions were voltage 100kV, current 50A, and resolution 1.12m. A full-diameter CT scan test was performed on ore samples, and the internal three-dimensional (3D) structure data volume of the sample was obtained for three-dimensional display. After that, different internal substances were extracted by using the gray difference for three-dimensional rendering. The internal structure of the ore was observed to understand the structural characteristics of the internal pores and fractures of the ore. Figures 9(a) and 9(b) show the three-dimensional display and rendering of iron ore. The red area shows the cracks. The cracks were extracted by threshold segmentation. The volume percentage of the study area (i.e., porosity) occupied by the cracks is 10.18%.

Figures 10(a) and 10(b) show the three-dimensional rendering of iron ore porosity. The extracted pores were marked with different colors for each isolated pore. At the same time, the pores were marked and sieved. The pore equivalent diameter (EqD) sieve is shown in Figures 11(a)11(h). The number of equivalent diameters of different pores and the percentage of the total pore volume are shown in Table 4.

The characteristic parameters such as porosity, coordination number, pore radius, and pore volume were obtained through the experimental exploration of the ore after coarse crushed by the gyratory crusher. The number of pore equivalent diameters in the range of 960m accounts for a relatively large amount, accounting for 88.01%. The maximum pore radius, the average pore radius, the maximum pore volume, the average pore volume, the maximum coordination number, the average coordination number, and the compressive strength are 11.414m, 1.678m, 121519m3, 335.833m3, 109, 3, and 148MPa, respectively (see Table 4).

In order to characterize the ore particle model well, bonded particle model (BPM) was selected. The BPM model was published by Potyondy et al. [29] and A. R. Hasankhoei for the purpose of simulating ore breakage. The approach has been applied and further developed by Cho et al. and Johansson et al. [30, 31]. The concept is based on bonding or gluing a packed distribution of spheres together forming a breakable body.

When setting the crushed ore particles, firstly, a certain amount of particles were combined to form ore particles through the bonding bond at a given time. When subjected to crushing force, the particles formed by the bonding bond will be dispersed to show the broken state. At this time, the bonding bond is broken. The larger the number of broken bonds, the better the crushing effect and the higher the product quality. This paper mainly analyzes the impact of different parameters on the crushing effect. Because of the large amount of crushed iron ore, the influence of the shape of the ore was not considered, and the iron ore model was equivalent to a spherical shape. Figure 12 shows a schematic diagram of ore model generation and crushing.

Since the particle size of the ore feed cannot be less than 100mm, the design iron ore model diameter is 100mm. According to the physical properties of the iron ore obtained by experiments, such as the porosity and coordination number, the diameter of the fraction used to fill the iron ore particles was determined to be 5mm. The empirical equation (17) for determining the number of filling particles given in the DEM was used to calculate the number of filling fractions:where is particle filling coefficient, is the volume of feed particle, is the number of filled fractions, and is the volume of filled fractions.

Firstly, import the crusher chamber model drawn by SolidWorks into the geometry module, and set the motion characteristics for each part. The movement of the mantle includes two: one is its own rotation movement, the speed is very low, generally 1015r/min, and the other is the eccentric movement around the axis of the concave. The eccentric movement speed is specifically set according to the optimization result, and the movement time is set to 5s.

Secondly, set the basic property parameters of iron ore and liner materials in the globals module, including density, Poissons ratio, and shear modulus. Define the properties of fraction particles and whole particles in the particle panel, including particle radius, volume, and mass. The fraction particle radius is 5mm. Because of the soft ball contact model, the actual contact radius is slightly larger than 5mm, which is defined as 5.5mm here, and the whole particle is 50mm.

During the operation of the crusher, the ore and the ore, and the ore and the liner are squeezed into each other. Therefore, it is necessary to separately set the coefficient of restitution between the ore and the ore, the coefficient of static friction, the coefficient of dynamic friction, and the three coefficients between the ore and the liner.

Finally, determine the simulation time step and divide the mesh. Generally, 2-3 times the radius of the smallest particle element is selected as the basis for meshing. In this simulation, 2 times the radius of the smallest particle element 5mm is selected as the ideal side length of the mesh element.

The time step is determined by the Rayleigh [13] wave method. For a system composed of different particles, the time step was calculated as follows:where is particle velocity, is particle density, is shear modulus, and is particle radius.

Simulation was carried out according to the parameters in Table 3, and the total number of ore bonding bonds N was set as 144,298. Figures 13(a)13(d) show the DEM simulation of the crushing process of the cone crusher at different moments and the velocity cloud diagram of the particles in the crushing chamber.

In Table 5, is the total number of ore bonding bonds and is the number of ore fracture bonds. The bottom angle of the mantle , the length of the parallel zone , and the eccentric angle are changed respectively for simulation. For different variable values, the corresponding number of ore fracture bonds and are shown in Table 5. The breaking rule of ore bonding bond with crushing time is shown in Figures 14(a)14(c).

It can be seen from the above that when the bottom angle of the mantle increases from 50 to 60, the number of bond breaks decreases from 130,589 to 118,901, and the broken percentage decreases from 90.5% to 82.4%. And when the length of the parallel zone increases from 140mm to 190mm, the number of bond breakages increases from 126838 to 136650 and the broken percentage increases from 87.9% to 94.7%. While when the eccentric angle increased from 1.4 to 2, the number of bond breaks increased from 115,149 to 122,941, and the broken percentage increased from 79.8% to 85.2%. The simulation value is slightly higher than the numerical calculation value, but the trend of the broken percentage with the change of the bottom angle of the mantle, the length of the parallel zone, and the eccentric angle is consistent.

By analyzing the movement state of the ore in the crushing chamber, the cone crusher productivity and product quality are used as the objective functions to study the influence of the chamber structure parameters on the crusher performance with the method of optimized numerical calculation. The main conclusions of this paper are as follows:(1)In order to obtain a more accurate productivity model, it is necessary to remove the blockage ore uplift in the traditional model. For this reason, considering the influence of the ore arching of the blockage layer in the A and D areas, the traditional productivity model was revised to improve the calculation accuracy of the crushers productivity. For the C900 cone crusher, the relative error of the revised productivity model calculation value is reduced by 16%.(2)Taking the parameters such as mantle bottom angle, parallel zone length, and the eccentric angle of the chamber structure as optimization variables, a dual-objective programming model about the productivity and product quality for the cone crusher was established. The optimal parameter matching scheme of C900 cone crusher performance was obtained: The swing speed of the mantle, the length of the parallel zone, the bottom angle of the mantle, the eccentric angle, the eccentricity, and the engagement angle are 285r/min,1 50mm, 55, 2, 44.8mm, and 23, respectively. After optimization, the productivity and the percentage of crushed products of the C900 cone crusher can be increased by about 2% and 2.1%, respectively.(3)Based on the physical characteristics of the iron ore after coarse crushing by the gyratory crusher, the discrete element method is used to simulate the crushing process. The simulation results are consistent with the trend of the numerical calculation results, verifying the feasibility and reliability of the dual-objective programming model of the cone crusher as well as the optimization numerical method.

Copyright 2021 Fengbiao Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.