Howden products are used throughout the cement production process. Our blowers are used to move the iron ore, calcium carbonate, silica and alumina immediately after extraction and continue to be used throughout the process and once the end product is generated and needs transported.
Once the raw materials have been crushed into raw meal, they are transported to the kiln and Howden fans play an important role in super heating the meal into the cement clinker and then to cool the clinker. The clinker then has gypsum added and is moved into the cement mill to be ground into the final product.
As the ever increasing demand for cement puts pressure on plant capacity and efficiency, our extensive experience in the industry allows us to revamp and upgrade fans and blowers, and increase cement manufacturers output.
We supply all the fans for a complete cement plant. These include the process critical fans, mainly centrifugal, for the pre-heater exhaust, kiln induced draught, raw mill exhaust, final exhaust, cooler forced draught and cement mill exhaust applications. We also supply all the other associated centrifugal and axial fans. We supply rotary positive displacement (Roots) blowers for cement conveying systems. Our experience in the cement industry goes back many years and we have supplied equipment in many parts of the world.
The abundance of mining activities continuously increases mine wastes/tailings that require storage/disposal. It is well understood that the accumulation of tailings around mines, and consequently, their spreading in the environment could cause serious ecological hazards. Reuse and recycling of mine tailing materials, in construction and earthwork applications (such as non-structural building elements, roads), offset possible environmental pollutions and safeguard natural resources. This study investigates experimentally the cement/bentonite stabilization of iron ore tailings from the Golgohar iron ore mine, which is the largest producer of raw (un-smelted) iron products in Iran. A comprehensive series of compaction and uniaxial compression tests was performed on mixtures of cement/bentonite and tailings. Test results reveal that the introduction of cement/bentonite to iron ore tailings requires higher water content for optimum compaction and results in lower dry density. The addition of bentonite increases the unconfined compressive strength (UCS) very little, whereas there is a great strength enhancement for tailing-cement mixtures, particularly after a period of moist curing. The cement-stabilized iron ore tailings may be incorporated in road constructions as they easily fulfill strength requirements of base and subbase course layers, while the bentonite-treated tailings are applicable as cover materials in layered disposal of tailings.
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Experiments were conducted in the Soil Mechanics Laboratory at the Department of Earth Sciences, Shiraz University. The second author would like to acknowledge Shiraz University of Technology. Thanks are due to Golgohar Mining and Industrial Company for providing the tailing materials. Also, the kind efforts of Dr. Saeid Maknooni (of Golgohar Mining and Industrial Company) are appreciated. The constructive comments and suggestions by the editorial board member and anonymous reviewers are greatly appreciated.
Barati, S., Tabatabaie Shourijeh, P., Samani, N. et al. Stabilization of iron ore tailings with cement and bentonite: a case study on Golgohar mine. Bull Eng Geol Environ 79, 41514166 (2020). https://doi.org/10.1007/s10064-020-01843-6
Mining Equipments, Crushing Machine, Drying Machine manufacturer / supplier in China, offering Good Quality Copper Ore Clay Brick Screen, PE 250*400 Mini Stone Jaw Crusher with Ce Certification, High Recovery Free Gold Gravity Concentration Processing Gold Shaking Table and so on.
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Q. My company uses iron ore (magnetite) in its process. However, a large amount of mill scale has become available and we are looking at it as a substitute or supplement. What is the basic composition of mill scale and the difference between it and magnetite and black iron oxide? Can mill scale be used in place of magnetite or black iron oxide?
Mill scale is the hardened, oxidized, surface that develops on steel as it is hot processed. It contains iron and oxidized iron but probably poorly defined contaminants like oils and carbonates. Putting this stuff into an unknown "process" might work excellently, or poorly, or fail completely -- but powder explosions of all sorts are a commonplace, and the large surface area could cause the reaction to proceed instantaneously and explode and kill people! Please try your best to explain what your intended "process" is. Thanks.
Q. Can anybody tell the difference between Iron Mill Scale, Black Iron Oxide, Magnetite (Iron ore)? If the basic composition is the same, can Mill scale be used in place of Black Iron oxide or Magnetite.
A. Well, there have been many attempts to use mill scale but all have failed because of structural faults in mill scale. It cannot be used in most applications but if you tell which application would you like to use it, I think all in the room can guide you better.
A. Well mill scale needs to be purified as it contains contaminants like sulphur and phos. magnetically it needs to be separated and texture modified by heat treating it to 670 C. then it can be used as magnetite.
A. Well I used to use about about 1,000 tons per year. It was used in a ferro-cement mix and poured into a polyethylene shell. These were sold as wheel weights for lawn and garden tractor wheels for extra weight for traction. Weights were 20-75 lbs.
Q. We are exploring the use of mill scale (small percentage) in our Pellet Plant coming up in India. We are beneficiating Iron Ore fines bearing Fe 56% to 300-325 mesh and then using a series of hydro-cyclones to bring the Fe up to 64%. I would like to explore the use of mill scale in crushed form (325 mesh/44 microns) for: 1. upgrading by green ball Fe content & 2. increase the quality of finished pellets in terms of reduction. Any suggestions / opinions / advice is solicited.
Q. I have a proposal to compact Mill scale (Fe 60% to 70%) from Steel Mills by briquetting it. The briquettes to be used along with heavy melting scrap in electric arc furnaces. There are briquetting machines available in the world market having a capacity to make 30 to 100 mts per hr of briquettes. The bonding used is Sodium Silicate and hydrated lime. I shall be grateful if you could advise if this method of recycling of Mill scale would be beneficial to steel making in the electric arc furnaces. The costs benefits are considerable given the demand and high prices for heavy melting scrap. Thanks for your time Regards,
Q. Dear sir I'm working in one of the alloy production company, since we started the production of LOW CARBON FERRO CHROME. For this we have taken CHROME ORE, AL POWDER, SODIUM NITRATE & MILL SCALE. I want to know the main usage of MILL SCALE in this chemical combination, that why we have to use MILL SCALE. Please clear my doubt
Q. I own a rolling plant producing structure angles and channels. It generates about 100 tonnes of mill scale per month. Is there some kind of technology that can convert mill scale back to pure Fe which can be melted in blast furnaces to produce ingots and billets. Also, can mill scale be directly melted to produce pure iron. I Would be more than happy to give more information if required. warm regards, Abhinav
---- Ed. note-- Gentle Readers: If you know enough about mill scale to be able to pose a question, you may know enough about it to be able to help one of the dozen people waiting in line in front of you. A dozen unanswered questions in a row can be the death of any public forum thread, so there really is no point in making the list of unanswered questions still longer. So we won't waste your time and ours adding additional questions until some answers are posted. Thanks for your understanding, and please try to help!
A. Mill scale is the result of an oxidizing layer of steel products as it is processed in a rolling mill. It is collected with coolant and lubricating oils and normally held in a collection tank/pond. During its mixture with the liquids the steel scale will oxidize further until it reverts to iron oxide (Fe2O3). If the scale is collected and dried right away some will be in the form of Fe, FeO, Fe3O4, Fe2O3 and the total Fe content could be as high as 99% or whatever level the steel products are at the mill. The size of the mill scale will be from dust size in microns up to normally 6 mm, perhaps longer as it is scale it will flake off the steel. Processes exist to recover and use the mill scale as well as all other iron/Fe bearing materials wastes in steel mills and use it directly in a furnace to make new steel.
A. Mill scale is oxides of iron and alloying elements present in steel. Obviously, it is a rich source of iron. Most of the steel plants recycle mill scale through sintering or pelletization. However, a value-added utilization of mill scale is in steel making after converting it into briquettes. Briquettes can be tailor made by combining with other Plant wastes, such as coke breeze, lime fines, and iron bearing wastes, to suit a particular utilization. It offers excellent techno-economic benefits. Yes, mill scale can be converted into pure iron by subjecting it to reduction process. Though it is time consuming, powder iron is manufactured through this route as well.
Q. I have a proposal to compact Mill scale (Fe 60% to 70%) from Steel Mills by briquetting it. The briquettes to be used along with heavy melting scrap in electric arc furnaces. There are briquetting machines available in the world market having a capacity to make 30 to 100 mts per hour of briquettes. The bonding used is Sodium Silicate and hydrated lime. I shall be grateful if you could advise if this method of recycling of Mill scale would be beneficial to steel making in the electric arc furnaces. The costs benefits are considerable given the demand and high prices for heavy melting scrap.Thanks for your time Regards Seshadri
Hi cousin Bivek. I don't know the answer to your question, but as the website operator for 20 years I advise that a good and helpful response is more likely if you explain the situation which motivates your question. I'm not here to lecture folks, only to advise what seems to work here. Best of luck, and I encourage someone to prove me wrong by answering anyway :-) Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey ^
Q. We are one of the leading steel plants in our area We are making MS ingots in our induction furnace. Mostly we are using both sponge iron and HMS (heavy melting scrap) as raw materials in our plant. Now a large quantity of mill scale (Fe 40%-50%) is available in our area. Can we use mill scale as raw material in our induction furnace. If yes, how to use?
A. Dear, you can use mill scale while processing of Magnetite in magnetic separator in low intensity after grinding and can be used in pellet making, but it will drop your final Fe in the pellet due to oxidation.
Q. Dear all, in my company we generate 3000 Ton/month of mill scale, 1000 Ton/month of DRI Muds and 3500 Ton/month of Iron Ore fine. We make briquettes of DRI dust and DRI fines with Sodium Silicate, but can't add the mill scale into the mix due to the briquette loses its resistance. Have some of you tried to make briquettes with these components? How much pressure is required? I would appreciate if someone can show me what type of machine is used for briquetting. And anyone know if there are other uses of DRI muds besides the cement industry? Thanks
Q. What standard test method( ASTM, ISO, etc.) is used to analyze "DOUBLE ROASTED MILL SCALE"? We follow iron ore method: We analyze Fe, Fe2O3, FeO, S, P. with compatibility. But problem is that our authority needs a STANDARD TEST METHOD INCLUDING IT'S SPECIFICATION. Please help me with relevant answer.
A. Sanjay, Even Google doesn't know what "double roasted" mill scale is. plain old "roasted" mill scale doesn't turn up much either. What kind of analysis are we talking about here? Thickness? Composition? Perhaps if we better understand what you are looking for, we will be more able to search up an existing standard.
Q. Good day, Please advise what is the best way to use Mill Scale in Induction Furnace for steel melting to assist in reduction of carbon content. If we do use mill scale in induction furnace what lining is recommended? As mill scale oxidizes and erodes silica lining, can neutral lining work?
Q. Is it possible to use a mixture of mill scale, coal (carbon source) and sand(silicon dioxide) for reduction into iron in silica lined induction furnace. As using directly affects the silica lining adversely so would be it be possible to introduce extra Carbon and silicon dioxide with the mill scale so that the lining is unaffected?
What is pre-decomposition technology? The core of the new dry process cement plant is suspension preheating technology and pre-decomposition technology. The clinker pre-decomposition technology refers to adding a new heat source, precalciner, between preheater and cement rotary kiln. When the fuel is injected into the precalciner for combustion, the raw material preheated to about 750 by cement preheater is fed into the precalciner at the same time so that the exothermic process of fuel combustion and the endothermic process of carbonate decomposition in the raw meal is carried out rapidly. Generally speaking, the cement raw meal decomposition rate can reach more than 90% before entering the rotary kiln.
What is precalciner? Precalciner, also known as cement calciner, is a kind of high-efficiency direct combustion solid-gas heat exchange cement equipment. It disperses and suspends cement raw meal powder in airflow, making fuel combustion and calcium carbonate decomposition happen in a short time (generally 1.5 ~ 3 seconds). To some extent, it replaces part of the calcining work of a cement rotary kiln. In the calciner, because the fuel combustion and the material endothermic reaction are carried out at the same time, there is no visible flame, but in a state of low-temperature flameless combustion at 820 ~ 900 .
At present, more than a dozen types of precalciners have been put into use. Although each has its advantages, its characteristics and functions are similar. According to the different movement form of airflow, calciner in cement plant can be divided into four types:
The tertiary air with a temperature of 200 ~ 250 is blown into the air chamber of the fluidized bed calciner by a high-pressure fan and then enters the inner chamber through the air cap so that the fuel and raw materials form afluid-bed.
The preheated cement raw meal (temperature is about 820 ~ 860, not exceeding 860), a certain amount of fuel, and hot air (kiln tail flue gas or tertiary hot air) are fed into precalciner at the same time. After entering the calciner, the fuel and raw meals are dispersed by high-speed airflow and in a suspension state at about 900. The fuel is flameless combustion in the calciner, and the heat released by it makes the calcium carbonate in the raw meal decompose at a high speed through a convection heat transfer and radiation heat transfer. Generally, this decomposition process can be completed in a few seconds, and the decomposition rate of the whole raw meal is as high as 85% ~ 95%, forming an efficient operation mode of combustion, exothermic, endothermic, and decomposition at the same time.
Precalciner forms the clinker calcining system in the new dry process cement plant together with cement preheater, rotary kiln, and cement cooler. In addition to cement calciner, AGICO also provides other high-quality clinker calcination equipment, such as cyclone preheater, cement rotary kiln, grate cooler, rotary cooler, etc.
AGICO Group is an integrative enterprise group. It is a Chinese company that specialized in manufacturing and exporting cement plants and cement equipment, providing the turnkey project from project design, equipment installation and equipment commissioning to equipment maintenance.