table of bond abrasion index for varied minerals-materials
The Bond Abrasion Test determines the Abrasion Index, which is used to determine steel media and liner wear in crushers, rod mills, and ball mills. Bond developed the following correlations based on the wear rate in pounds of metal wear/kWh of energy used in the comminution process.
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high pressure grinding roll for advanced crushing |flsmidth
The F-series HPGR, developed by FLSmidth, incorporates a combination of engineered solutions and optimised components. Our design is derived from our years of maintaining these machines in the field and aimed at decreasing maintenance downtime, while placing special emphasis on the health and safety aspects of these operations.
Our HPGR is flexible enough to be highly suitable for both brownfield expansions and greenfield installations. The wide variety of ways our customers are already using the machine shows just how helpful the technology is.
Our HPGR is a perfect complementary tool to work in conjunction with, and even enhance the performance of traditional grinding mills and fixed-gap crushers. The HPGR exposes feed material to very high pressure for a short amount of time. The compression typically causes the rock to crack and cleave along the grain boundaries, weakening the rock structure and exposing the ore particles. This high pressure also creates a large amount of fines and causes the formation of microcracks in the larger particles, lowering the Bond work index of the ore and reducing the ball mill power required downstream.
The F-Series HPGR is ourfull size machine used in large mining projects throughout the world. Operation, maintenance and service personnel collaborated to create this modern HPGR design. With it, you get a reduced footprint, convenient and safe handling for heavy components and improved shipping.
We re-designed our legacy roll press to upgrade it and optimise it for mining duty, and the result is our S-Series HPGR. Though this series is meant for smaller projects, plants and retrofits, it is packed with plenty of the same features that are in our larger models. And the smaller size means that your machine can be shipped partially or fully assembled, resulting in a faster installation.
The lower section of our HPGR feed chute, which typically experiences the highest wear, is lined with FLSmidths patented FerroCer Impact Wear Panels. Our wear panels haveproven to greatly outperform conventional wear plates in this application where the feed ore is often large, very hard, and highly abrasive. These panels are easy and safe to install, while providing the longest possible wear life. Learn more about where else in your plant operation you can optimize your durability with FerroCer Impact Wear Panels.
The planetary reducers are shaft mounted to the rolls and are linked together via the torque sharing arm assembly. This saves you money because it eliminates the cost of additional foundation structure and hardware to bear the torque arm reaction forces.
This feature also allows the drive train to be captured and held in place during roll change-out using our (optional) drive retraction cradle, which further optimises the roll change-out time and makes the procedure safer.
Mounting the hydraulic cylinders to the frame with hinges allows maintenance personnel to safely access and inspect these components without getting inside the framework of the HPGR. For any maintenance that required removing the cylinders, overhead access is free and clear of the frame with the hinges in the outboard position. Dual-acting means that no special tools are required to separate the rolls to clear tramp metal. By simply reversing the oil flow, the hydraulic cylinders can be used to retract the rolls and allow the tramp to fall through, getting the machine back online quickly.
The HPGR has a skid mounted tank with a lubrication oil conditioning system that supplies clean filtered and temperature conditioned oil to the roll bearings. A constant flow of oil carries the contaminants and heat that are generated in operation away from the bearings to maximising uptime. The lubrication oil system instrumentation monitors and protects the system. In contrast, conventional grease lubricated units are messy, require frequent relubrication and must be water cooled.
We designed the hydraulic pumping system to the cylinders with advanced skew control (ASC) and use linear variable differential transducers (LVDTs) to monitor the system. As skewing starts to occur in the floating roll, the ASC system adjusts the press force applied to the hydraulic cylinders, keeping the roll assemblies as near parallel as possible during operation, while at the same time maintaining interparticle contact and grinding efficiency over the roll width.
There are two frame styles offered for industrial applications. The S-Series, which incorporates a traditional box frame design, has been optimised for smaller plants. The F-Series, using our express frame, accommodates the need to handle and operate larger and heavier components.
We designed and built our express frame for a faster and safer replacement of the roll surfaces. With the minerals processing industry trending towards larger equipment, we specifically developed the express frame to handle larger, heavier components in a safer and easier manner.
This new frame uses a tapered pin and bushing concept. Removal of the tapered bushing creates more clearance space for inserting and removing pins. A wedge jacking system takes the load off the pins for quick extraction and replacement.
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.
grate-kiln pelletization of indian hematite fines and its industrial practice | springerlink
Indian hematite fines normally have a high iron grade and minor impurities; they are usually used as sinter fines for feeding into a blast furnace. In this work, the grindability properties of two kinds of Indian hematite fines and the roasting behaviors and induration characteristics of pellets made from these fines were revealed through experiments involving dry ball milling and small-scale and pilot-scale tests. In addition, the microstructures of the particles of ground India hematite fines and fired pellets were investigated using optical microscopy. On the basis of the results, a grate-kiln production line with an annual output of 1.2 Mt of oxidized pellets was established in India. This pellet plant operates stably and reliably, further confirming that preparing high-quality pellets with Indian hematite fines pretreated by dry ball milling is an industrially feasible process.
G.P. Singh, R.P. Choudhary, H. Vardhan, M. Aruna, and A.B. Akolkar, Iron ore pelletization technology and its environmental impact assessment in eastern region of India: a case study, Procedia Earth Planet. Sci., 11(2015, No. 6, 582.
S. Dawrapudi, T.K. Ghosh, A. Shankar, V. Tathavadkar, D. Bhattacharjee, and R. Venugopal, Effect of pyroxenite flux on the quality and microstructure of hematite pellets, Int. J. Miner. Process., 96(2010, No. 14), 45.
G.D. Kalra, Iron ore pellets as a solution to steel-making raw materials at the crossroad and dominant constituent of basket of iron ores available for export in the future, Miner. Econ., 26(2014, No. 3, 127.
M. Gent, M. Menendez, J. Torao, and S. Torno, A correlation between Vickers hardness indentation values and the Bond work index for the grinding of brittle minerals, Powder Technol., 224(2012, No. 5, 217.
N. Prieto Martinez, M. Herrera Trejo, R. Morales Estrella, M.J. De Castro Romn, R. Mata Esparza, and M. Carren Villareal, Induration process of pellets prepared from mixed magnetite-35% hematite concentrates, ISIJ Int., 54(2014, No. 3, 605.
D.Q. Zhu, Z.Q. Guo, J. Pan, and F. Zhang, Synchronous upgrading iron and phosphorus removal from high phosphorus Oolitic hematite ore by high temperature flash reduction, Metals, 6(2016), No. 6, article No. 123.
O.A. Mohamed, M.E.H. Shalabi, N.A. El-Hussiny, M.H. Khedr, and F. Mostafa, The role of normal and activated bentonite on the pelletization of barite iron ore concentrate and the quality of pellets, Powder Technol., 130(2003, No. 13), 277.
C.C. Yang, D.Q. Zhu, J. Pan, B.Z. Zhou, and X. Hu, Oxidation and induration characteristics of pellets made from Western Australian ultrafine magnetite concentrates and its utilization strategy, J. Iron Steel Res. Int., 23(2016, No. 9, 924.
D.Q. Zhu, J. Pan, M. Emrich, and V. Mende, Use of vale hematite pellet feed in Chinese pelletizing plants, [in] Annals 3rd International Meeting on Ironmaking and 2nd International Symposium on Iron Ore, Maranhao, 2008, p. 472.
This work was financially supported by the National Natural Science Foundation of China (No. 51474161) and the Hunan Provincial Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources.
Zhu, Dq., Zhang, F., Guo, Zq. et al. Grate-kiln pelletization of Indian hematite fines and its industrial practice.
Int J Miner Metall Mater 24, 473485 (2017). https://doi.org/10.1007/s12613-017-1428-z
ironmaking process - an overview | sciencedirect topics
The ironmaking process in the blast furnace is a heat and mass transfer process, and the furnace can be divided into different zones according to physical and chemical state of the feed and temperature. Figure 1.1.5 illustrates various zones of the blast furnace and feed distribution and materials flow . Corresponding to each temperature interval, typical reactions will take place. The descending burden is dried and preheated during its descent by the ascending gas. The preheated blast is blown into the furnace through the tuyeres in the lower part of the furnace. Oxygen in the blast reacts with coke carbon to produce carbon monoxide and blast humidity reacts with carbon to produce carbon monoxide and hydrogen:
The role of nitrogen in the blast is to act as a heat carrier together with CO, CO2, and H2. The combustion space in front of the tuyeres is called the raceway. The adiabatic flame temperature in the raceway is about 21002300C. The ascending hot gas heats up the dripping iron and slag, which are collected in the hearth below the tuyere level and tapped at certain intervals. The ascending gas flows through the cohesive zone, also called softeningmelting zone. Here iron and slag become soft, and they separate and melt down. The slag phase contains some unreduced iron oxide FeO. The reduction of this iron by solid carbon is called direct reduction:
These reactions diminish when gas temperature falls below 900C. Reduction reactions, increasing in CO2 content and cooling of the gas continue along with its ascending. The remaining heat content of the gas is used to dry and preheat the burden before the gas leaves the furnace top at 100300C. The top gas is still a valuable fuel having a lower heating value of 34MJ/Nm3.
After the relatively rapid heating to about 900C, the burden reaches the chemical reserve zone where the temperature difference between gas and solid is about 50C. At about 10001100C (depending on the chemical composition of the ferrous burden and the reduction degree), the burden comes to the cohesive zone. Iron oxides are mainly reduced to metallic Fe. The burden starts to soften. Iron and slag separate. The FeO content in slag phase can vary inside a large range, e.g., 525%. Metallic iron is carbonized by carbon in the coke and CO gas and melts at 12001300C. Molten iron and slag drip down through the coke layer to the hearth where they reach their final temperature and composition.
The BF ironmaking process is currently the dominant process for providing steelmaking raw materials worldwide. However, the BF process relies heavily on metallurgical coke and involves cokemaking and sintering operations, which often attract serious environmental concerns. Therefore, DR and SR technologies using noncoking coal or other gases as reducing agents to replace metallurgical coke are expected to emerge as future alternative routes for iron production. Due to the vast difference in operating conditions between these processes, different quality parameters are imposed by their operators on ferrous burden to ensure the efficiency and economics of the process. To quantify these quality parameters, a variety of standard and nonstandard physical tests have therefore been developed. The standardized tests are simple but generally are conducted at fixed conditions, which often represent the extreme situations encountered by ferrous materials. However, while nonstandardized physical testing methods are very sophisticated, they simulate the working conditions that the ferrous materials encounter more closely. Therefore, nonstandard physical tests are recommended in addition to standard physical tests when unfamiliar burden materials are used. Finally, because different ferrous materials have distinct characteristics, a comprehensive burden evaluation program allows the plant operator to maximize productivity at the lowest cost by optimizing the burden composition.
Regardless of the ironmaking process, sulfur and phosphorus are generally undesirable elements in any raw material, since they can make the final steel product brittle and weak. Often limestone (CaCO3) or dolomite (CaMg(CO3)2) is added with the feed to an RK and mixed with iron ore concentrate to act as a desulfurizing agent. The specification for sulfur in RK-grade coal in India is a maximum of 1% . The maximum moisture content allowed in the same coals is 7%.
One disadvantage of the coal-based technologies is that they often bring significant levels of impurities with them, as part of the coal ashfor the low-grade Indian coals, ash can be as high as 27.5% of the coal . This ash is typically made up of common slag-forming components such as SiO2, Al2O3, CaO, MgO, and FeO, though other oxides and sulfides are often present. The exact mix of components in a particular coal ash can be criticalfor example, ash containing more than 70% silica can react with ferrous oxide (FeO) to form a low-melting point compound (fayalite, Fe2SiO4) that interferes with the reduction process .
A schematic diagram of the flash ironmaking process is given in Figure 4.5.30. Natural gas or hydrogen will be partially combusted with industrial oxygen through a burner on top of the flash reactor to generate a reducing gas stream at 16001900K. Iron ore concentrate will be injected in the vicinity of the burner and will undergo reduction reaction as it flows down. Although this figure displays the version of the process wherein the reduced iron is collected as a molten bath for the possibility of direct steelmaking in a single unit, the reduced product may also be collected as solid particles and briquetted to be charged in separate steelmaking furnaces.
In the new process, the concentrate will be reduced to a high degree of metallization in suspension in a hot reducing gas generated by the partial combustion of natural gas, heavy oil, hydrogen, or a combination thereof.
The flash ironmaking process is initially expected to be operated using natural gas as a fuel and reducing agent. Natural gas is an abundant readily available resource in the United States. According to the 2011 Annual Energy Outlook , the estimations on the United States production rate of natural gas predict a steady increase. Further, there is a big push to increase natural gas production in the United States from its considerable reserves. The recently discovered reserves in Marcellus Shale  represent a good example of this trend. For an annual production of 20million tons of iron, which would represent about 40% of the current United States production rate, the flash ironmaking process would require 0.33TCF/year (trillion cubic feet per year) of natural gas. This represents less than 1.5% of the total United States consumption rate (22.7TCF/year) . As a comparison, this is similar to the 1.5% of the total United States energy consumption used by the United States steel industry. When natural gas is used as a reducing agent, the proposed process will produce iron with varying carbon contents such as the iron produced by HYLs ZR self-reforming process . In the latter process, carbon levels can be up to 5.5%.
Hydrogen would be the cleanest reductant and/or fuel from the viewpoint of environmental concerns and reduction kinetics. There is much expectation for the development of hydrogen economy and thus the availability of inexpensive hydrogen, for which much effort and resources are being devoted [67,68].
The proposed technology is to be applied either as an ironmaking step, with the product to be fed directly to the secondary steelmaking units such as an EAF, bypassing the converting step like BOF, or as an integral part of a continuous direct steelmaking process from the concentrate . A silicon-free, lower carbon iron, as will be produced by the proposed process, is used in the LD-ORP (LD converter-optimized refining process) of NSC (Nippon Steel Corp.) or in NSCs converter-based all scrap melting process with coal. Alternatively, carbon could be added in the briquetting step, or the EAF could be modified by adding a lance for gas injection to promote optimum slag foaming, rather than relying on CO produced from dissolved carbon, to enhance the refining and steelmaking reactions.
Although the new technology under development at the University of Utah is aimed at eventually replacing the BF, it could be used, on a moderate scale, to increase output in a conventional integrated steel plant by utilizing COG as a hydrogen source not only by extracting its hydrogen content but also by reforming the methane present therein.
The flash ironmaking process will remove many of the limitations associated with other alternative processes. Specifically, (a) direct use of iron oxide concentrates without the need for pelletization or sintering; (b) no cokemaking required (if coal is used to generate the hot reducing gas, pulverized coal of wide variety can be used); (c) high temperature can be used because there will be no particle sticking or fusion problems; (d) possibility to produce either solid or molten iron; and (e) low refractory problems, ease of feeding the raw materials, and the possibility of direct steelmaking in a single unit, as shown in Figure 4.5.30.
An important condition for the proposed process is whether iron oxide concentrate can be reduced to a high metallization degree within the few seconds of residence time available in a typical flash furnace. This issue will be addressed below together with others that need to be resolved before the new process becomes ready for commercialization. Suffice it to note here that the rate is sufficiently fast for the reduction of iron ore concentrate in a flash reaction process above 1450K [60,69].
Ironmaking and steelmaking slags are inevitably generated as a by-product from ironmaking and steelmaking processes. Main components of the slags are CaO, SiO2, Al2O3, MgO, and iron oxides, and the compositions of slags depend on the process. In the case of Japan, three types of slags, namely BF slag, BOF slag, and EAF slag are mainly produced, which amount is shown in Figure 4.4.11  and the typical compositions of each slag are summarized in Table 4.4.2 . Main component of BF slag is SiO2 and Al2O3, coming from iron ore as gangue minerals, and CaO added as a flux during sintering process. On the other hand, BOF slag mainly contains CaO added as a refining agent, and SiO2 and iron oxides produced by oxidation refining process. The EAF slag is classified into two types, oxidation slag and reduction slag, which are produced during steel refining and reduction of iron oxide to metallic iron, respectively.
Slag compositions of constituents entrained from gangue components depend on the compositions of raw materials, while those of other constituents added as a flux for refining processes are designed to maximize its refining performance, and thus there is a wide variety of components and compositions of slags. Approximately 300kg/ton-pig iron and 100kg/ton-steel of BF slag and steelmaking slag (BOF or EAF slag) are generated. Totally 24, 11, and 2.9 million ton of BF, BOF, and EAF slags (FY2011) are produced in Japan .
Common slag treatment process in Japan is shown in Figure 4.4.12 . About 80%  of BF slag is quenched by water spray and the quenched BF slag sand produced is used mainly for cement, concrete and civil engineering resources. The rest is cooled by field air cooling and the slow cooled slag is used as a resource for road construction, concrete coarse aggregate, and so on. On the contrary, since steelmaking slag contains iron droplets at several percents in weight the slag cannot be quenched by water splashing. Therefore, slag is treated by field air cooling and then crushed and screened. Iron droplets are recovered by magnetic separation and remained slag is sold for various purposes such as civil engineering, cement or concrete resource. BF slag is completely recycled, while small fraction of steelmaking slag cannot be utilized due to the elution of hazardous elements such as heavy metals or fluorine. Development of new technologies to use such slag is an important solution to reduce the amount of slag landfilled without any utilization.
Regarding the measure to decrease the environmental load by slags generated from ironmaking and steelmaking processes, following two methods are considered. The first is the reduction of generated slag amount by development of highly efficient processes. Metallurgical slags have been mainly designed to increase the refining capability as a function of slags so far. Recent process and slag designs are based not only on the improvement of the refining capability but also on the reduction of environmental load such as the decrease of slag amount, discontinuation of the use of hazardous elements, or the development of the process which generates recyclable by-products (slags). The second measure is the development of the new utilization method of slag as a resource. Utilization method of the ironmaking and steelmaking slags as an abundant resource should be developed by creating new functions and additional values.
The carbonization of coal has its historical roots in the iron and steel industries. The ironmaking process developed around the Mediterranean Sea spreading northward through Europe (Attig and Duzy, 1969). Historians state that the Phoenicians, Celts, and Romans all helped spread ironmaking technology, with one of the ironmaking techniques spread by the Romans as far north as Great Britain. Originally, charcoal produced from wood was the fuel used to melt the iron ore. A tremendous amount of wood was needed for this industry. For example, one type of furnace, the Stuckofen, used in fourteenth century Germany could produce 4000 pounds of iron per day with a fuel rate of 250 pounds of charcoal per 100 pounds of iron produced (Wakelin, 1999). This was an early version of the charcoal blast furnace and these furnaces that developed in continental Europe soon spread to Great Britain.
By 1615, 800 furnaces, forges, or ion mills existed in Great Britain, with 300 of them blast furnaces. The rate of growth in the number of these furnaces was so great and their consumption of wood so high that during the 1600s parliament passed laws to protect the remaining forests. Consequently, many blast furnaces were shut down, alternative fuels were looked for, and England encouraged the production of iron in its North American colonies, which had abundant supplies of wood and iron ore. The first successful charcoal blast furnace in the New World was constructed outside of Boston at Saugus, Massachusetts, in 1645.
As a result of the depletion of virgin forests in Great Britain to sustain the charcoal iron, the iron masters were forced to look at alternative fuel sources. The alternative fuels included bituminous coal, anthracite, coke, and even peat (Wakelin, 1999). The development of coke and anthracite ironmaking paralleled each other and coexisted with charcoal production during the 1700s and 1800s, while the use of bituminous coal and peat never became a major ironmaking fuel. The wide use of coke in place of charcoal came about in the early 1700s when Abraham Darby and his son demonstrated in 1708/1709 that coke burned more cleanly and with a hotter flame than coal (Berkowitz, 1979). Up until 1750, the only ironworks using coke on a regular basis were two furnaces operated by the Darby family (Wakelin, 1999). However, during the period 17501771, the use of coke spread with a total of 27 coke furnaces in production. The use of coke increased iron production because it was stronger than charcoal and could support the weight of more raw materials, and thus furnace size was increased.
The use of coke then spread to Continental Europe: Creussot, France in 1785; Gewitz, Silesia in 1796; Seraing, Belgium in 1826; Mulhiem, Germany in 1849; Donete, Russia in 1871; and Bilbao, Spain in 1880 (Wakelin, 1999). In North America, the first attempt to use coke as 100% fuel was in the Mary Ann furnace in Huntington, Pennsylvania, although coke was mixed with other fuels as early as 1797 in United States blast furnaces.
The efficient use of coke and anthracite in producing iron was accelerated by the use of steam-driven equipment, the invention of equipment to preheat air entering the blast furnace and the design of the tuyeres and the tuyere composition (Wakelin, 1999). The evolution of both coke and anthracite ironmaking paralleled each other in the United States during the 1800s, and by 1856 there were 121 anthracite furnaces in operation. With coke being the strongest and most available fuel, the evolution of 100% coke furnaces continued with major steps being made in the Pittsburgh, Pennsylvania area between 1872 and 1913. The Carnegie Steel Company and its predecessor firms developed technological process improvements at its Monongahela Valley ironmaking furnaces that ultimately made it possible for the United States to take over worldwide leadership in iron production. This is not true today, however, as much of the steel production has shifted overseas beginning in the 1960s and early 1970s.
Cokeless technologies can be divided into two principle groups: carbon-based (directuse of coal and biomass products) and hydrogen- or electricity-based ones.The first group, which includes SR processes (with some restrictions, see Section13.5.1) and coal-based direct reduction processes, may diminish but not solve the problem of CO2 emissions. By the second group of methods, the crucial point is themass hydrogen or carbon-free electricity production at a reasonable price. Atransition period from carbon- to hydrogen-based iron and steel production is unavoidable.
Carbon serves until now as a main chemical reactant to convert iron-bearing materials to iron and steel, and CO2 is an unavoidable by-product of this reaction. The amount of carbon required is dictated by laws of chemistry, physics, and thermodynamics. Since many decades, CO2 emissions in the steel industry reflect the primary energy consumption (Fig.13.17, left side). This dependence makes it hardly possible to mitigate further carbon dioxide emission in the most energy-intensive ironmaking sector. The best performing BFs operate with energy consumption close to the thermodynamic limit while using the high-quality raw materials.
The following ways can be considered as short and midterm measures to break the direct dependence of CO2 emissions on primary energy consumption (Fig.13.17, right side) and to counteract the lowering quality of raw materials by using the BF process as well as DR and SR ironmaking processes (Babich etal., 2016; Babich and Senk, 2017):
In the process of stack gas injection some hydrocarbon fuel is reformed to a mixture of H2 and CO and this gaseous reducer is injected into the lower stack of the blast furnace. This process was investigated by several authors and steel plants and is thought to be a proper candidate for lowering CO2 in the ironmaking process. The results of these experimental investigations have been reviewed in the state-of-art paper of Rhee  and are summarized in fig.3. The data are from the experimental and real blast furnace tests of the different institutions like CRM, NKK, Nippon Steel and U. S. Bureau of Mines already done during 1960s and 70s. The effectiveness index of the stack gas injection in lowering coke consumption in the blast furnace can be expressed in the sense of effective (CO+H2) volume per ton hot metal which is calculated from the content of partial pressures of CO, H2, CO2, and H2O in the injected gas stream. Fig.3 shows that the coke consumption can be lowered proportionally to the effective (CO+H2) volume.
Fine and ultra-fine ferrous ores must first be agglomerated to produce sinter or pellets respectively. Lump ore may be charged directly to a blast furnace but only after it has been suitably sized and screened to remove overand undersize material. Lump ore, however, usually comprises a minor portion of the total ferrous feed. Coal cannot be directly charged via the furnace top, it must first be transformed to coke.
Raw materials are charged to the furnace in alternating layers of coke and ore. This alternating layer structure inside the furnace has a profound impact on the operation of the furnace and on the required quality of coke. This in turn has an influence on the VIU of the parent coals used to make that coke.
For many ironmaking plants coke is an expensive raw material and/or is in short supply. Pulverised coal (PCI) may be injected through the tuyeres as a substitute for coke. However, PCI has some fundamental impacts on blast furnace operation, which will be discussed later. Because of these impacts only ~40% of coke requirements may be replaced by coal injection.
Internally the blast furnace is considered to consist of five discrete zones, see Fig.17.2, through which all furnace gases and/or liquids must pass. The location, shape and extent of each zone is influenced by the properties of the material layers (relative thickness, etc.) and by the properties of the materials themselves. These factors interact to determine the flow and distribution of gases within the furnace. It is the distribution of gas flow within the furnace which largely determines the four most important aspects of ironmaking profitability:
iron ore grindability improvement by microwave pre-treatment - sciencedirect
The influence of microwave pre-treatment on grindability of iron ore (Orissa, India) was investigated by grindability tests. SEM analysis characterized the micro-fractures in microwave treated sample. This may be due to the thermal stress cracking resulted from microwave energy pre-treatment. XRD analysis showed the crystalline content of the sample. It was found that the microwave treated iron ore has peak more than that of untreated ore, i.e. the crystallinity increased with the microwave exposure time. The calculation of HGGI indicated increase in the ease of grinding or decrease in grindability index of the microwave treated ore. Grindability test showed that the microwave treated iron ore grinds much more rapidly initially than the untreated ore. The results showed that the breakage function of both microwave untreated and treated iron ore is dependent of the particle size. The grindability increased significantly as a result of microwave pre-treatment with the specific rate of breakage (Si) increasing by an average of 50%. It was concluded that microwave assisted grinding produced good results particularly for grinding characteristics.
crushing&screening system for mineral processing | prominer (shanghai) mining technology co.,ltd
For mineral processing project, after blasting, crushing and screening system is always the first stage to reduce the big raw ore lumps to proper small particle size for following mill grinding system. Normally to reduce the big ore lumps to small particles, two to three stages crushing is required.
Prominer has the ability to supply complete crushing and screening system, including various crusher, screen, belt conveyor, iron remover, etc. For minerals with different properties and hardness, we can recommend suitable crusher accordingly, including jaw crusher and cone crusher for hard material, impact crusher and roller crusher for relatively soft material. In addition, for some mineral projects, the mining sites are in different locations, which is far from processing plant, and Prominer can also supply portable crushing station to make the crushing and screening from one mining site to another to make it convenient.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.