ball mill grinding media calculation fl

calculate and select ball mill ball size for optimum grinding

In Grinding, selecting (calculate)the correct or optimum ball sizethat allows for the best and optimum/ideal or target grind size to be achieved by your ball mill is an important thing for a Mineral Processing Engineer AKA Metallurgist to do. Often, the ball used in ball mills is oversize just in case. Well, this safety factor can cost you much in recovery and/or mill liner wear and tear.

cement milling

Cement milling is usually carried out using ball mills with two or more separate chambers containing different sizes of grinding media (steel balls).Grinding clinker requires a lot of energy. How easy a particular clinker is to grind ("grindability") is not always easy to predict, but large clusters of belite due to coarse silica in the feed are difficult to grind. Rapid cooling of the clinker is thought to improve grindability due to the presence of microcracks in alite and to the finer crystal size of the flux phases.

Vertical roller mills (VRMs) are the main alternative means of grinding the clinker and are increasingly being used. For a quick introduction to VRMs see, for example, this advertisement on Youtube for an FL Smidth VRM.

Because the cement gets hot due to the heat generated by grinding, gypsum can be partly dehydrated, forming hemihydrate, or plaster of Paris - 2CaSO4.H2O. On further heating, hemihydrate dehydrates further to a form of calcium sulfate known as soluble anhydrite (~CaSO4). This is calcium sulfate with a trace of bound water in the crystal structure and it has a very approximately similar solubility in water at room temperature to hemihydrate, which in turn has a higher solubility than either gypsum or natural anhydrite.

The relative proportions and different solubilities of these various types of calcium sulfate, and of the different forms of clinker sulfate, are of importance in controlling the rate of C3A hydration and consequently of cement set retardation. Problems associated with setting and strength characteristics of concrete can often be traced to changes in the proportions of the different forms of calcium sulfate due to differences in temperatures during grinding. Variations in cooling rate of the clinker in the kiln and subsequent changes in the proportions or size of the C3A crystals may also have an effect on setting characteristics.

If the rate at which sulfate is supplied by the different sulfate salts exceeds the rate at which the clinker minerals, principally the aluminate phase, can react, the pore solution may become supersaturated with respect to gypsum. Crystals of gypsum form which cause the mix to stiffen in what is known as a false set.

Conversely, if the rate at which sulfate is supplied is insufficient to control aluminate reaction, the mix will stiffen due to the fomation of monosulfate crystals, or possibly of calcium aluminate hydrate; this is known as flash set.

For set regulation, the most important feature of aluminate is not necessarily the absolute amount present, but the amount of surface which is available to water for reaction. This will be governed by many factors, such as the surface area of the cement, the grinding characteristics of the different phases and also the size of the aluminate crystals. Over-large crystals can lead to erratic setting characteristics.

Articles like this one can provide a lot of useful material. However, reading an article or two is perhaps not the best way to get a clear picture of a complex process like cement production. To get a more complete and integrated understanding of how cement is made, do have a look at the Understanding Cement book or ebook. This easy-to-read and concise book also contains much more detail on concrete chemistry and deleterious processes in concrete compared with the website.

Almost everyone interested in cement is also concerned to at least some degree with concrete strength. This ebook describes ten cement-related characteristics of concrete that can potentially cause strengths to be lower than expected. Get the ebook FREE when you sign up to CEMBYTES, our Understanding Cement Newsletter - just click on the ebook image above.

solutions to improve the production capacity of jaw crusher

Production capacity is the quantitative index to measure the processing ability of jaw crusher. The production capacity of jaw crusher directly affects the economic profits of investors. And the production capacity of jaw crusher is affected by many factors, such as the properties of raw material (hardness, size, and bulk density), type& size of jaw crusher, operation condition of jaw crusher and so on. And the low production capacity is mainly caused by the low discharging capacity. In this article, we mainly introduce some solutions to improve jaw crusher production capacity.

The nip angle means the included angle between movable jaw plate and fixed jaw plate. According to calculation, the max nip angle can reach to 32, but in the actual production, the nip angle is generally between 18-20, smaller than 25. If the nip angle is too large, the raw materials in crushing cavity will be squeezed out of the cavity, which may hurt operators or damage other auxiliary equipment. At the same time, with the increasing of nip angle, the crushing ratio also increases, but the production rate will decrease.

In the actual production process, we can change the size of nip angle by adjusting the discharge opening according to requirements about the final products size. In this case, under the premise of ensuring the final products size, we should adjust the discharge opening. While adjusting the discharge opening, operators should pay attention to the relation between crushing ratio and production rate.

In certain range, properly increase the revolutions of eccentric shaft can also improve the production capacity of jaw crusher, but it will also increase the energy consumption for crushing per unit raw material. If the rotation speed is too fast, the crushed raw materials in crushing cavity will not have enough time to be discharged, which will cause the blocking of jaw crusher. In this case, the production capacity will decrease, but energy consumption will increase. From this we can see that, proper revolution of eccentric shaft is very important.

Through dynamics and physics principle analysis, in order to improve the production capacity, we can change the shape of movable jaw plate, making the nip angle in the lower part as 0 while the nip angle of the upper part stays the same. In this case, the original crushing cavity is divided into two parts: crushing cavity and discharging cavity. The raw materials get crushed in the crushing cavity and discharged from the discharging cavity. Raw materials pass through in unit time increase, the production capacity also gets improved.

In jaw crusher, eccentric shaft, connecting rod, movable jaw plate, fixed jaw plate, scale board are the main wear-resistant parts, operators should pay attention to the lubrication and maintenance of these parts. Once found damage, operators should repair or change the worn parts timely in order to keep the high production capacity of jaw crusher.

By optimizing the shape of movable jaw plate or discharge opening, we can optimize the crushing cavity, enhance improve the discharge capacity and production capacity. At the same time, operators should also lubricate or maintain the related spare parts and optimize the related parameters in order to improve the production capacity.

trommel frames and screen media | flsmidth

FLSmidth has fully engineered a new range of trommel frames and screen media for SAG Mills, ball mills and scrubbers. As your partner in productivity, we combine our in-depth knowledge of equipment and applications, providing a comprehensive approach to improve your processes.

All mines want to reduce unexpected events and downtime. Withour trommel frames, you can rest assured that your equipmentis of the highest quality engineered to be strong and lightweight,and designed to increase your uptime and provide safe handling.

To extend and maximise your asset life, we verify the structuraldesign of our trommel frames through finite element analysis (FEA).This guarantees the engineering behind all components of the frames. Completedesign using anFEA calculation includes static and fatigue/strength assessment, as well as strength assessment on the bolts. We stress relieve your trommel frame afterfabrication and beforemachining. We also apply protective lining on each frame inthe areas that are likely to be exposed to erosive and abrasive wear.

To ensure rapid delivery and streamline inventory management, ourscreening media is available in two standard sizes and in a numberof thickness combinations. Our modular screen media panel sizesare 657 mm 400 mm (25.86 in15.75 in) and 726 mm 400 mm(26.75 in 28.58 in). These standard dimensions allow us to supplyyour media from any FLSmidth manufacturing centre, and guaranteeyour media will conform to our unparalleled quality requirementsand material specifications, while providing equal fabricationreproducibility.

Our experienced engineers are committed to finding thebest solutions. We examine every aspect of your screeningprocess to help ensure efficient pulp flow characteristics, proper separation, maximum wear life and maximum equipment uptime.

We use our state-of-the art discrete element modeling (DEM)software to simulate your trommel performance. We then model,predict, optimise and enhance your assets for the highest possible recoveries and efficiencies.

We offer screening media in a variety of steel and polyurethane grades and rubber composites. Our newest grade of polyurethane media was developed as we partnered with a trusted prepolymer supplier to combine the physical properties of rubber and polyurethane elastomers. This new addition to our offered materials has been proven in the field to be tough and long lasting even under harsh operating conditions.

As a leading supplier of mineral processing equipment, we have many years of experience with the advantages and limitations of each type of media so that we can provide media recommendations that are as customised as your processes. Triple your panel wear life.Download our recent trommel panel case study.

Our media optimisation assistance works to improve production because we start with an array of the highest quality media options and then we perform an in-depth analysis of your product, feed and operating conditions to determine the best material for you.

As part of our efforts to help you select the best media for your needs, we use technological tools such as discrete element method (DEM) software. We use the software to simulate pulp flows through the surface of your screen. With this information we can project the discharge rate, wear patterns and material distribution over the screen.

In the end, this process reduces your operating and maintenance costs. One of our recent customers found that their wear life was tripled when they allowed us to help them with their media selection and did a trial of our newest grade of polyurethane. Download our recent case study here.

Customised trommel frames and screen media make every step of your process better. With proper optimisation help, you get the operation improvement youre looking for while at the same time increasing the ease and safety of the related procedures.

Our unique trommel frame design has friction-grip clip rails for installing the modular panels, as opposed to bolts or pins, reducing your downtime for screen maintenance. The customised screen material options decrease maintenance frequency by maximising wear life.

The washing system is custom-designed and manufactured to deliver efficient washing and recovery of fines that adhere to oversize material. These fines are undesirable, as they can interfere and affect downstream processes, such as pebble crushing.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

size reduction of solids crushing and grinding equipment | springerlink

The unit operation of the size reduction or comminution of solids by crushers and mills is a very important industrial operation involving many aspects of powder technology. It is estimated that mechanical size reduction of rocks, ores, coals, cement, plastics, grains, etc. involves at least a billion tons of material per year in the United States alone. The operation ranges in scale, for a single device, from a few kilograms per hour for speciality products to hundreds of tons per hour for metallurgical extractive purposes. In this chapter, the fundamental aspects are emphasized rather than mechanical or process engineering aspects, to form a background for intelligent decisionmaking in the choice and analysis of size reduction systems.