chromite magnetic separator sudan

five chrome extraction process to teach you the chromite ore processing - xinhai

In all rare metals, the importance and scarcity of chrome ore and scarce are most obvious, which is at the top of "strategic metals". The chrome ore is mainly used in the production of stainless steel and various kinds of alloy steel in the form of ferroalloy (such as ferrochrome), which has the advantages of strong hardness, wear-resisting, heat-resisting and corrosion resistance.

At present, the common chrome extraction processes mainly include gravity separation, magnetic separation, electric separation, flotation, gravity-magnetic separation process. Below, let's take you to learn about each chromite ore processing process.

From the point of production practice, the gravity separation is still the main chrome extraction method in the world method now, which uses the loose stratification in the water medium. At present, the gravity separator used in the chromite ore processing includes the shaker table, jig, spiral chute and centrifugal separator.

It is worth noting that stage grinding and gravity separator, or the combination of various gravity separators can be used according to the chrome ore properties, thus further improving the grade and recovery of chrome concentrate.

Because the chromite has a weak magnetism, we can use the strong magnetic separator for chrome extraction. There are mainly the following two cases: one is in the weak magnetic field, remove the ore in the strong magnetic separation of minerals (main magnetite), improve the ratio of ferrochrome. Another is to separate the gangue minerals and recover chrome ore (weakly magnetic mineral) under the strong magnetic field. If necessary, the weak magnetic - strong magnetic separation process can also be used to effectively separate the ore and achieve the chrome extraction.

The electric concentration process is mainly used to separate chromium ore from silicate gangue by using the difference of electrical properties of minerals, such as conductivity, dielectric constant, etc. For the chrome ore, a few chrome can be used directly by the electrical concentration, most of them only use the electrical concentration process in the concentration process. The concentration process has a special effect on removing silicate minerals (such as quartz, etc.) from chrome. Therefore, after the separation of chrome, another stage of the electric concentration process can be added for cleaning, which not only further improves the grade of chrome concentrate, but also greatly reduces the content of silicon dioxide.

At present, we can use the flotation process to recover the chromite with fine grain size (-100um) after the gravity separation. The results show that Mg2+ and Ca2+ can inhibit the chromium ore, and the inhibition of Mg2+ is influenced by the type of anions in the slurry. Therefore, after knowing the cationic behavior in the pulp, we can choose the appropriate pulp PH value, reagents concentration, add the order of inhibitors and activators, achieve the separation of chromite and pyrite.

Sometimes, the single gravity separation method cannot recover the chrome concentrate effectively. At this time, the concentrate obtained by the gravity separation can be separated by weak magnetic separation or strong magnetic separation, further improving the grade of chrome concentrate and chromic oxide-ferrous oxide ratio.

For example, the 100-10mm grade of raw ore adopts two-stage dense media separation. The medium ore of the dense media separator is crushed to 10-0mm and then merged with the 10-0mm grade of raw ore for separation. The grades of 10-3mm and 3-0mm are sent to the jigging process. After the middling of the jigging process is ground to 0.5-0mm, the spiral concentrator is used for separation, and the shaker table is used for the separation of mineral mud (0.5-0mm). Then, the high-field magnetic separator is used to recover 0.25mm slime separated from the tailings of the shaker table and spiral separator, ensuring the content of chromium oxide in the concentrate and reduce the loss of valuable components in the tailings.

Here are the common five chrome extraction processes. For the rich ore with high chromium oxide content, single gravity separation or magnetic separation process can be adopted. For the chrome with low chromium oxide content, the combined process of gravity separation and magnetic separation usually gets a better index than the single process. Of course, the specific chrome extraction process should be determined comprehensively according to the nature of the chrome ore, the actual situation of the chromite ore processing plant, the investment budget, so as to ensure the ideal beneficiation benefits and economic benefits.

chromite - an overview | sciencedirect topics

Chromite ores, as might many others, be mined by open-pit and underground methods. The share of underground mining varies between countries and deposits. The extracted ore is subjected to crushing and sorting (normally rich ore containing more than 45% Cr2O3 is supplied to the processing plant, whereas lower-grades are subjected to different dressing procedures).

The main consumers of chromite ore are the ferroalloy, refractory, and chemical industries, which have different demands for the ore and the concentrates, both in terms of the impurity ingredients and in grain-size composition (Table 8.4).

A typical technological process of chromite ores enrichment includes a series of operations (Lyakishev and Gasik, 1998): screening of the input ore, slurry rinsing-off, and heavy media separation. The slurries formed are subjected to wet screening, dehydration, filtration, and drying. The major parameter, changing in these phases, is the SiO2 concentration gradually changing to <7, 5, 3, and 1%. Because these low-silica concentrates are represented by finer fractions, it is important to prepare the product in lumpy forms (pellets, briquettes). It has been recommended that fine concentrate should be granulated and roasted (~1800C).

The most common method is gravity concentration (heavy-media separation, screw separators, and concentration tables). Aside from the gravity method (in various modifications), flotation methods are used (separately or in combination with gravity methods), as well as concentration in a strong magnetic field. Magnetic concentration in a weak field is also used to extract magnetite from chromium ore before flotation or to extract it from chromium concentrate after flotation (Kurochkin, 1988; Lyakishev and Gasik, 1998). Wet high-gradient magnetic separation is usually thought to be the most promising method for improved performance. Chromite ore can be separated in a high-strength field, despite the presence of iron impurities. The choice of method depends on several factors, primarily the type of the gangue.

In some cases, separation and dressing methods are optimized to take into account other useful elements, such as PGM (platinum group metals) in South Africa, where noble metals extraction (besides chromium) is of high importance. Along with gravity-flotation and magnetic methods, hydrochemical (hydrometallurgical) technologies are being developed.

Besides these ore dressing methods, combined techniques are also possible, especially when the chromite quality is low. In India, low Cr:Fe ratio chromites are briquetted with coke and selectively reduced at 1250C. Treated briquettes are crushed, ground, and leached, leading to the higher Cr:Fe ratio concentrates with chromium extraction exceeding 95%.

The authors have estimated that more than 75% of chromite ores are represented by fine fractions and the remaining share is represented by lumpy ores. Electric furnaces consume approximately two thirds of all mined chromite ore, and there the optimum operating conditions are achieved with large sorted chromite ore. For metallurgical processing of high-chromium concentrates, usually present in the finest forms, they have to be agglomerated. Although some successful experiments were made for smelting of ferrochromium in various metallurgical furnaces using fines, this technology has not yet been implemented on an industrial scale. For chromites agglomeration, three main methods are being exploited: sintering, palletizing, and briquetting.

Sintering technology originates from the similar method used for iron ores agglomeration. Many combinations of ores, carbon fuels, moisture content, and binders (bentonite) have been studied. An example of different versions of sinter charges is shown in Table 8.5. The addition of iron ore depends on the required Cr:Fe ratio, fines fractions, and chromite quality.

The pelletization of chromite fines and concentrates is usually based on mixing chromites, binder (bentonite), recycled material, and possibly coke fines and roasting at sufficiently high temperatures (1200 to 1300C). It is known that roasting in air results in better pellet quality due to the oxidation of iron (2+ to 3+) taking the octahedral sites in spinel structure. A minor share of coke fines in the pellets gives the possibility of raising the temperature and gets more uniform temperature distribution inside the pellet. However, a better resistance to impact and abrasion was achieved in pellets with no fuel additions. During roasting, sulfur is removed from the pellets by 70% to 80% (due to oxidation of sulfides like pyrite). The remaining sulfur is of the sulfate type (magnesium and calcium sulfates). Some examples of pelletization technology parameters by different sources are shown in Table 8.6.

Briquetting as a method for agglomeration of fine fractions is widely used in ferrous and nonferrous metallurgy. Unlike sintering or pelletization, it is possible to make briquettes of single component (monobriquettes). In many cases, briquetting was reported to be commercially competitive with sintering or pelletizationthe latter is associated with high capital investment, high cost of the grinding and roasting, demand for low SiO2 content because of possible sintering of pellets when they are roasted in rotary kilns, and so on. The clear environmental advantage of briquettes versus lumpy ore is in the reduction of dust emissions by 1.5 to 2.5 times.

In developing a technology for briquetting of chromite ore, it is important not only to study the mineralogical and grain-size characteristics but also to make a proper choice of the type and quantity of the binder and the conditions for pressure and heat treatment of raw briquettes (Sen et al., 2010). It should be noted that it is very difficult to make recommendations about briquette quality with a particular charge and processing parameters, as well as whether they would be suited for effective smelting of ferrochrome in a submerged arc electric furnace (Pavlov et al., 2010). For example, briquettes in the furnace bath are also a current conductor, so extra coke in briquettes may lead to their premature destruction in the case of high current density. On the other hand, briquettes produced by this method are a good regulator of electric resistance in the charge.

Different compositions have been suggested for briquetting chromites using coal, tar resin, sulfite solution (lye), lime, and so on. One of the recommended briquetting methods is as follows (although it should be remembered that no defined remedy recipe exists for briquetting all types of chromite ores). The ore of the 6 to 10-mm fraction is dried and mixed with hydrated lime to which mixture molasses is added at 35 to 40C. The formed briquettes are 2 to 5 inches long, 1 to 2 inches thick, and 1.5 to 2.5 inches wide, and they are stored in piles; their strength increases slowly with holding, reaching maximum values (8 to 25 MPa) after 10 to 12 h. The briquettes retain their strength values even in humid conditions (for shipping and handling, >8 MPa is considered a sufficient limit). The exact mechanism behind the process of strengthening is not known, but some have speculated that it is related to calcium hydroxide carbonization or molasses transformations.

Chromite ore with a small amount of coke is ground wet in a ball mill, after which the resulting slurry is de-watered. It is mixed with a binder before being fed into a rotating drum or disc pelletizer, where it forms balls. Pelletizing occurs due to the rolling motion of the pelletizer without the application of pressure. The fines adhere to each other because of the moisture. The green pellets are screened to select the required size. Undersized particles are returned to the inlet of the pelletizer.

Green pellets are charged into a sintering furnace, which may be a vertical shaft furnace, although horizontal traveling grate sintering furnaces where the pellets are conveyed on a perforated steel belt are more common. After the raw pellets enter the furnace, they are heated gradually to between 300C and 350C, which removes the water from the pellets and allows the binding material to form chemical bonds. The heat required for this operation is obtained from hot air, which is drawn through the grate past the pellets. As the pellets progress into the furnace, the temperature is increased to the sintering temperature of 1250C to 1350C where the metallic ores are fused together. Heat for this stage of the process is supplied by gas burners and the coke. Waste CO gas from the submerged arc furnace or natural gas or liquefied petroleum gas may be used. As the pellets move through the downstream section of the furnace they are cooled. The sintering furnace operates as a counterflow heat exchanger. Cold air enters the sintering furnace in the cooling section, where it is drawn through the grate and past the pellets, thereby cooling them. After cooling the pellets, the gas flows into the heating section where heat is transferred to the pellets. The sinter furnace operates at a negative pressure, with airflow driven by induced draft fans. The exhaust gas is cleaned in a venturi scrubber, cyclone, or bag filter plant after leaving the furnace. Dust is returned to the sinter plant feed system. Pellets are discharged onto a conveyor that takes the sintered pellets past a series of screens to the storage bins. Undersized pellets are returned to the sinter plant feed system. Sintered pellets may be used as feed for kiln prereduction, fed into a preheater, or fed directly into the furnace.

Lanthanum chromite LaCrO3, belonging to the perovskite oxide, has a high melting point (2490C); it is corrosion-resistant and has stable chemical and physical properties at high temperatures [8]. When doping the alkaline earth elements, La3+ ions of the crystal structure can partially be replaced by Ca2+, Sr2+, Mg2+, etc. LaCrO3 was first of interest as the electrode of MHD generator, and since then it has been widely applied as the heating element in high temperature furnaces and the interconnection materials in solid-state oxide fuel cells (SOFCs). Recently, some applications on NTC thermal resistor, plasma spraying materials, and magnetic materials have been developed [9]. In the recent studies of lanthanum chromite, the authors are mainly focused on the sintering process, electrical conductivity, and stability.

Perovskites with transition metal ions (TMIs) on the B site revealed a huge range of fascinating electronic and magnetic characteristics. This type is related not only to their chemical flexibility, but to a wider extent to the complex characteristics that transition metal ions demonstrate with oxygen or halides in specific coordinations [10]. Transition metal perovskites are used as capacitors, transducers, actuators, sensors, and electro-optical switches. Doped chromites are utilized in SOFCs as interconnecting materials [11].

Naray-Szabo (1943) [12] and Wold and Ward (1954) [13] were the first to report on the crystal structure of LaCrO3. They proposed it as a perovskite material with cubic structure, Pm3m space group, and lattice parameter ~3.90. Utilizing neutron diffraction, Khatak and Cox (1997) [14] indicated that at RT, LaCrO3 exhibits an orthorhombic structure, with Pnma space group and lattice parameters a=5.475, b=7.754, and c=5.513. Numerous other researchers referred to LaCrO3 as a material that presents a distorted perovskite structure at RT [15,16]. The substitution at the A or B sites, or both of them, could greatly enhance the electrical characteristics and compatibility with other cell constituents, regarding thermal expansion characteristics. For example, doping with Ca, Sr, Mg, and Ni in LaCrO3 is utilized to diminish densification temperatures or times, or both of these, owing to its great stability [1719].

Compared to chromite, magnetite is abundantly present in many ore deposits. Notably, it is ubiquitous in porphyry CuAuMo and porphyry Mo deposits worldwide. In porphyry-style deposits, magnetite usually forms early in the paragenesis, signaling moderately oxidizing preore conditions. ReOs data for magnetite are limited, in part because many magnetite-bearing deposits in the porphyry environment contain readily datable molybdenite for precise and accurate age information. For some IOCG deposits where magnetitehematite is an economic commodity, molybdenite is also available to establish the age of the IOCG mineralization (Skirrow et al., 2007). In doing so, it is important that the contemporaneity of magnetite and molybdenite is well established in the field.

ReOs data for titanomagnetite are reported from the intertwined FeTiV oxide and FeCuNi sulfide deposits in the Suwalki anorthosite massif, NE Poland (Morgan et al., 2000). Compared to Re and Os concentrations in coprecipitating sulfide, the titanomagnetites register an order of magnitude lower concentrations. Variation in Re and Os concentrations for magnetites is attributed to sub-mm to micron-size sulfide inclusions, unavoidable during mechanical separation of mineral phases. The 187Re/188Os ratios for magnetites, therefore, present maximum values, with corresponding sulfide phases containing much higher 187Re/188Os.

Similarly, ReOs data for magnetite-rich samples from the Biwabik banded iron formation, Minnesota, show low concentrations of both Re (<2ppb) and Os (<30ppb), with consistently low Re/Os ratios (<7; Ripley et al., 2008). As with chromitites, the iron oxide phases are useful for Os tracer studies, but not geochronology.

In a ReOs study of magnetitepyrite sample pairs from the Cala IOCG mine in the Ossa Morena Zone of SW Iberia, pyrite is clearly observed postdating magnetite. Pyrite veinlets engulf and penetrate massive brecciated magnetite. A 7-point magnetitepyrite ReOs isochron suggests a sudden change in oxidation state at the FrasnianFamennian boundary without significant change in the Re and Os concentrations in the fluid (Carriedo et al., 2007; Stein et al., 2006).

The refractoriness of chromite bricks is about 17001850C, depending on the ore used. Their R.U.L. is poor and they cannot be trusted beyond about 1400C owing to the possibility of there being MgO.SiO2 in the bond (see Fig. 68). Spalling resistance is very poor, thermal conductivity being about the same as that of magnesite. The colour is distinctively black and the density high at 3 g/cm2. The only valuable property is an extremely high resistance to attack by either acid or basic slag.

Chromite brick is the most neutral refractory and its limited uses all exploit this unique feature. The most important application is as a single neutral course between the basic walls and acid roof of a basic open-hearth furnace. It also appears in the bottom of some soaking pits, protecting firebrick from FeO, and in acid open-hearth furnaces protecting SiO2 at the ports. Other possible applications, e.g. at slag lines or in ladles, are limited by the poor general properties.

For interconnect applications, chromite ceramics demonstrate certain advantages including excellent high-temperature stability, good CTE matching to ceramic cell components, and a satisfactory electronical conductivity. However, these electronical conductive ceramics face a number of challenges. As mentioned earlier, the chromites are difficult to sinter to a high density that is required for interconnect applications. As ceramics, these interconnect materials are also hard to fabricate, which increases the cost of interconnect, in addition to expensive raw materials. Furthermore, the chromites tend to lose oxygen in reducing environment, causing lattice expansion at the anode side. For example, when exposed to hydrogen at 1000C, La0.8Sr0.2CrO3 and LaCr0.85Mg0.15O3 experience an expansion of 0.3% and 0.1%, respectively. This unsymmetrical size change due to oxygen loss often leads to warping and even cracking, adversely affecting the fuel cell stack stability.

Concentrates made from UG2 ores contain considerable chromite, FeCr2O4. The melting point of the slag is raised because of the chromite content. In addition, the chromium from the chromite may cause precipitation of the (Fe,Mg)Cr2O4 spinel, which has a melting point of about 1600 C, in cooler parts of the furnace (Nelson et al., 2005). This precipitated spinel may, in turn, prevent efficient settling of matte (Jones, 2005).

Problems associated with chromite are minimized by (i) rejecting chromite to tailings during flotation; and, (ii) minimizing the internal recycle in the smelter complex of high-chromium materials, such as converter slag, to the smelting furnace.

However, the general problem with chromite is only found in steel casting operations where it is commonly employed as a facing sand for silica molds. Here the surface of the casting can become coated in so-called chromite glaze, the result of chromite being fluxed by silica or clay, or simply by the decomposition of chromite as discussed below. This is difficult to remove and results in a poor finish to the casting (Petro and Flinn 1978).

The chromite glaze problem has been assumed to be the formation of fayalite (ferrous orthosilicate Fe2SiO4 with a melting point of 1205C) as the reaction product between silica and chromite. Fayalite is not magnetic and so cannot be separated from the sand magnetically. During the recycling of the sand this low-melting-point constituent therefore builds up, lowering the refractoriness of the molding aggregate. It seems likely that another ferrous silicate, grunerite (FeSiO3), also non-magnetic, with a melting point of about 1150C may also contribute to the impairment of the foundry sand for ferrous castings. These issues have yet to be properly researched and clarified.

An additional problem with chromite is that it is not particularly stable at steel casting temperatures. In oxidizing conditions it slowly oxidizes to Fe2O3 and Cr2O3 but in the presence of carbon from organic binders its iron oxide constituent can reduce to liquid iron. Drops of liquid iron form microscopic beads on the surfaces of the sand grains (Scheffer 1975, Biel et al. 1980) causing the sand to become highly magnetic (as quickly tested by the reader with a hand-held magnet). The reducing conditions are of course avoided by the use of carbon-free inorganic binders such as silicates. Whether oxidized or reduced, the weakened grains subsequently crumble to fragments.

Most chromite sand is derived from crushed ore, and so as well as being therefore rather angular, dust is created during conveyance which in turn increases the risk of reaction with silica sand. In general, it is estimated that 2030% of chromite sand is lost each time that the sand is reused.

However, the general problem with chromite is only found in steel casting operations where it is commonly employed as a facing sand for silica moulds. Here the surface of the casting can become coated in so-called chromite glaze, the result of chromite being fluxed by silica or clay, or simply by the decomposition of chromite as discussed later. This is difficult to remove and results in a poor finish to the casting (Petro and Flinn, 1978).

The chromite glaze problem has been assumed to be the formation of fayalite (ferrous orthosilicate Fe2SiO4 with a melting point of 1205C) as the reaction product between silica and chromite. Fayalite is not magnetic and so cannot be separated from the sand magnetically. During the re-cycling of the sand, this low melting point constituent therefore builds up, lowering the refractoriness of the moulding aggregate. It seems likely that another ferrous silicate, grunerite (FeSiO3), also non-magnetic, with a melting point of about 1150C may also contribute to the impairment of the foundry sand for ferrous castings. These issues have yet to be properly researched and clarified.

An additional problem with chromite is that it is not particularly stable at steel casting temperatures. In oxidisingconditions, it slowly oxidises to Fe2O3 and Cr2O3 but in the presence of carbon from organic binders its ironoxide constituent can reduce to liquid iron. Drops of liquid iron form microscopic beads on the surfaces of thesand grains (Scheffer, 1975; Biel et al., 1980) causing the sand to become highly magnetic (as quickly tested by thereader with a hand-held magnet). The reducing conditions are of course avoided by the use of carbon-free inorganicbinders such as silicates. Whether oxidised or reduced, the weakened grains subsequently crumble to fragments.

Most chromite sand is derived from crushed ore, and so as well as being therefore rather angular, dust is created during conveyance which in turn increases the risk of reaction with silica sand. In general, it is estimated that 2030% of chromite sand is lost each time that the sand is reused.

chromite separation solution and equipment omega foundry machinery - castings sa | castings sa

Omega Foundry Machinery have recently supplied chromite separation equipment to a foundry in the UK, a system that provides up to 99% pure reclaimed chromite sand by using a combination of drum magnet separators and a fluidised density separator, according to the company.

The foundry produces castings in over 200 compositions of carbon, alloy and stainless and nickel based alloys. They supply to the petro-chemical, oil & gas industry as well as structural, offshore, tunnelling, mining and steel plant applications.

Previously the foundry had a single rare earth drum magnet that was used to remove as much chromite sand from the reclaimed silica sand as possible (prior to thermal reclamation) and then dispose of it. The intention of the foundry was to invest in new equipment in order to recover as much good quality chromite sand as possible from the moulding sand so that it can be effectively re-used at the mixer.

The problems faced The problems faced by the foundry was that because chromite sand is para-magnetic, that is it is only slightly magnetic it (chromite sand), cannot be effectively removed by standard rare earth magnets without contamination of the metal and the silica. Even with a series of drum magnet separators, what tends to happen is that there is always a carry-over of silica sand making the quality of the reclaimed chromite poor and only suitable for dumping.

Principle of operation Fully attrited and cooled sand is held in a dirty sand silo and is discharged onto the in-feed electromagnetic feeder for an even and controlled feed over the primary ferrite drum separator. The feeder ensures that the product is thinly spread over the drum to enable maximum effect from the magnet.

The ferrite magnet removes all of the metallic particles from the sand, including chromite gangue, which is rejected allowing the remaining sand mix to then pass to a second electromagnetic feeder (chromite sand and silica sand blend). The second electromagnetic feeder provides feed to a high intensity magnet, which attracts the para-magnetic chromite from the fused silica/chromite sand mix.

The reject from the rare earth magnet is mainly silica sand, discharging to a surge hopper and pneumatic conveyor, which is then transported back to the moulding shop as mechanically reclaimed sand to the silica sand storage hopper for re-use.

Both magnetic drums have an adjustable gate within the casings allowing the sand streams to be finely tuned, the metallics from sand on the ferrite magnet and the chromite from silica on the high intensity magnet. The magnetic quadrant can also be adjusted in respect to its position, for maximum recovery.

The chromite product containing chromite, fused silica/chromite passes to the fluidised density separator. This material is automatically discharged onto a third electromagnetic feeder, in order to ensure the product remains evenly spread. Discharge via a chute is onto the fluidised separator.

The chromite sand particles being heavier are not lifted by the fluidising air and are driven forwards by the vibratory line of action of the motors. The reject particles being lighter are lifted off the membrane by the fluidising air. This prevents the particles being driven forward by the vibratory line of action of the motors onto the membrane. As the deck is inclined the lighter sand will flow backwards over the weir. The line of action and angle of the fluidised separator are adjustable to enable a precise split to occur. As material AFS and sieve analysis can be similar, there will be a small percentage carryover, but not excessive to cause re-use issues.

The fluidised separator has three product streams. The first is a waste stream of fused silica and any other waste that has managed to pass over the magnets. The second stream is reclaimed chromite sand. The third stream is any agglomerates that have inclined with the chromite and are rejected as the chromite product passes through an integral mesh panel bonded within the body of the separator. This chromite product can then be collected in big bags for re-use or collected in a surge hopper and conveyed pneumatically to chromite sand storage.

The plant is controlled from a main control panel with PLC and HMI, fully interlocked and with level probes at appropriate points for level and system control. The plant is designed to be fully automatic and self-supervising with no running adjustments or regulation necessary once commissioned.

Conclusion The separated chromite sand contains less than 0.5% silica contamination and therefore is perfect for re-use at the mixer. As a general side effect from the casting process, the chromite sand tends to see most of the heat from the molten metal and so is also naturally thermally reclaimed.

The foundry now blends the reclaimed chromite with new chromite at a ratio of 50/50 and uses it on the pattern face as chill sand as well as in the cores. Chromite dumping has been virtually eliminated and new chromite purchasing has been drastically reduced as well.

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Welcome to Mineral Processing Technologies. Our main goal is to always achieve a high level of customer satisfaction with the services and products that we provide. This simple approach has effectively fueled our growth since we opened our doors in March 2014. Were thrilled youve decided to visit us - please browse our site to discover what were all about.

Minprotech established the first Wet High Intensity Magnetic Separation (WHIMS) plant for chromite recovery in South Africa.Minprotech is the market leader utilizing WHIMS technology to extract chromite from UG2 and LG reefs.Our first full production plant was built and operated by us for a major chrome producer on the Eastern Chrome Mines.Minprotech subsequently procured another five plants that we operate for a large chrome producer. We produce an additional 20 000 tons of metallurgical grade chrome from our clients tailings. (current arisings & hydro mining)Minprotech owns and operates its own full-scale test facility, situated at our head office in Rustenburg.We have our own chemical engineers and metallurgical personnel that are responsible for on-going operational optimization.The feed PSDs, production yields and grade are constantly compared in our test plant to ensure that our equipment always deliver the best possible results.The best solution for chromite recovery lies in a combination of spirals and magnetic separation.Minprotech carries ample stock to minimize downtime and are running five plants with a 98 % availability.Minprotech is a Generic level 4 BEE company.Our company employs more than 100 people that varies from operational managers, engineers, metallurgists, HR and safety officers as well as the best operational staff in the industry!

This is one of our most popular services available. Its made a big difference for many of our customers, and is provided with the highest level of excellence. With this service, we ensure all details are simple, seamless and handled in a timely manner. Whenever you work with Minprotech, you can trust that youre in great hands.

Minprotech technicians and metallurgical personnel are specialized in the READING WHIMS technology and hold critical spares at their Rustenburg premises as a first line support base.All equipment can be installed, commissioned and maintained by Minprotech South Africa.

Our business model consists out of a toll arrangement whereby Minprotech provide a workable solution and remuneration based on final product produced. Customized process solutions can also be engineered for different applications.Minprotech can:Do all relevant test workDesign, fund and build the plant.Operate the plant.Our current model to own operate and maintain has proven to yield huge profits and low risk for our clients!

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Magnetic separation has gained force with the advent of high gradient and field Keywords High gradient magnetic separation, iron ore, wet magnetic separation. . Separator) is a pilot machine with a feeding capacity of 250 kg/h (dry basis).

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Improvement in Cr Fe Ratio of Indian Chromite Ore for Ferro Chrome Jan 3 2012 improvement of the off grade chromite ore ofSukinda region India Keywords Cr2O3 was treated in wet high intensity magnetic separator Get price JXSC MINING - Gold Shaking

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chromite sand separation plant by sogemi | foundry-planet.com - b2b portal

The chromite sand use has been increased in the steel foundries in last two decades. The chromite is used as facing sand due to its high conductivity of heat that avoids the sintering of the sand in contact with the molten metal and so permit to reach a good surface of the castings.Starting from a mixture in granular size of silica sand and chromite sand, Sogemi plant is able to separate completely the chromite sand from the silica sand.

After these different steps, by means of two pneumatic conveyors , the silica sand and the Chromite sand are transported in the required storages.Sogemi plant can provide a Chromite sand purity up to 99 %.

Sogemi has realized its first Chromite separation plant in 1994, in one steel foundry Cividale s.p.a that works with alpha-set process, phenolic-alcaline process.In this foundry Sogemi has combined its Chromite separation plant with its thermal reclamation plant: by means of this combined system the chromite separated sand is thermally reclaimed and re-used and utilized at 100% in the process without adding new chromite sand.In our experience hence there two ways to utilize the Chromite separation plant (depending on the type of castings production and chemical binder):

After this first plant, with a capacity of 6 t/h, Sogemi has installed many others Chromite separation plants in Europe, Russia and Brazil as well, in different foundries with different chemical process, like polyurethane, alkaline, sodium silicate etc and with different capacity starting from 6 t/h up to 20 t/h. The last plant in 2013 has been installed in Brazil , in Jundiai SanPaolo Area , in Wier Minerals do Brazil foundry .

magnetic separation studies on ferruginous chromite fine to enhance cr:fe ratio | springerlink

The Cr:Fe ratio (chromium-to-iron mass ratio) of chromite affects the production of chrome-based ferroalloys. Although the literature contains numerous reports related to the magnetic separation of different minerals, limited work concerning the application of magnetic separation to fine chromite from the Sukinda region of India to enhance its Cr:Fe ratio has been reported. In the present investigation, magnetic separation and mineralogical characterization studies of chromite fines were conducted to enhance the Cr:Fe ratio. Characterization studies included particle size and chemical analyses, X-ray diffraction analysis, automated mineral analysis, sink-and-float studies, and magnetic susceptibility measurements, whereas magnetic separation was investigated using a rare earth drum magnetic separator, a rare earth roll magnetic separator, an induced roll magnetic separator, and a wet high-intensity magnetic separator. The fine chromite was observed to be upgraded to a Cr:Fe ratio of 2.2 with a yield of 55.7% through the use of an induced roll magnetic separator and a feed material with a Cr:Fe ratio of 1.6.

J.F. Papp and R.L. Bruce, Industrial Minerals & Rocks: Commodities, Markets, and Uses, J.E. Kogel, N.C. Trivedi, J.M. Barker, and S.T. Krukowski, eds., Society for Mining, Metallurgy, and Exploration, 2006, p. 309.

C.R. Kumar, S. Tripathy, and D.S. Rao, Characterisation and pre-concentration of chromite values from plant tailings using floatex density separator, J. Miner. Mater. Charact. Eng., 8(2009), No. 5, p. 367.

M. Dobbins, J. Domenico, and P. Dunn, A discussion of magnetic separation techniques for concentrating ilmenite and chromite ores, [in] The 6th International Heavy Minerals Conference Back to Basics, The Southern African Institute of Mining and Metallurgy, 2007, p. 197.

S.K. Tripathy, V. Singh, Y.R. Murthy, V. Tathavadkar, P.K. Banerjee, and N. Suresh, Particle characterisation and magnetic separation behaviour of iron bearing minerals in Sukinda chromite ores, [in] XXVI International Mineral Processing Congress (IMPC) 2012 Proceedings, New Delhi, 2012, p. 5521.

Tripathy, S.K., Banerjee, P.K. & Suresh, N. Magnetic separation studies on ferruginous chromite fine to enhance Cr:Fe ratio. Int J Miner Metall Mater 22, 217224 (2015). https://doi.org/10.1007/s12613-015-1064-4

chromite - sciencedirect

Chromium (Cr) is a versatile element used in numerous applications in the metallurgical, chemical, foundry sand, and refractory industries. Chromite (FeCr2O4) is the only commercially recoverable source of Cr. South Africa holds approximately three-quarters of the world's viable chromite reserves. Kazakhstan, India, Russia, Turkey, Finland, and Iran follow this country. According to data from the International Chromium Development Association, global chromite use was 29.4metric tons in total (each unit equals 1000kg) in 2014, used 96% in metallurgical, 2% in chemical, 2% in foundry sand, and 0.2% in refractory industries. Because of the industry processes in these sectors, large quantities of Cr are discharged as liquid, solid, and gaseous wastes into the environment and can ultimately have significant adverse biological and ecological effects. Residues from mining and chromite processing are often toxic, not only because of the presence of hexavalent Cr (Cr(VI)) but because of the reagents and other waste materials in overburden and wastes. Governments have undertaken to update some Cr regulations, many of which have resulted in stricter standards. Current efforts are being made to reduce waste or eliminate its hazardous components. This chapter provides information regarding chromite resources in the world: specifically in Turkey, the raw materials used in the Cr industry and waste that is generated, toxicity of the waste to humans and plants, and recovery of useful products from the chromite industry, including recovery processes.

steinert moh for two-stage separation of medium grain sizes steinert

The STEINERT MOH is a combination separator consisting of a STEINERT MTP and a STEINERT EddyC thus combining two sorting stages into one compact design. The sortable material is placed directly onto the magnetic drum separator equipped with permanent magnets. High extraction of ferrous materials is guaranteed due to their ferromagnetic properties, since this first sorting stage operates in discharge mode. The non-magnetic fraction in contrast falls directly onto the acceleration belt of the downstream eddy current separator. Non-ferrous metals can thus be ideally separated from the remaining material prepared in this manner. This process arrangement is specifically designed for medium-sized grain ranges. You naturally have the option of choosing from the existing STEINERT non-ferrous metal separator series and adapting our solution to fully meet your requirements.

steinert finesmaster for multi-stage recovery of metals steinert

The processing of fine-grained material in metal recycling has developed into a lucrative business in recent years. At STEINERT we have already for a long time been supporting the metal separation sector with proven solutions, such as our magnetic drums, magnetic pulleys and eddy current separators. The STEINERT FinesMaster now offers you a complete system concept without complex interfaces, installations and control technology and represents the complete STEINERT solution to your "more" in terms of efficiency, especially in the sorting of fine metals.

The special feature of the STEINERT FinesMaster is its compact combination of proven sorting modules into one single unit without long supply routes and transition points. Module 1 comprises a two-stage magnetic separator (STEINERT MRB); it is used for the recovery of clean fine iron and the separation of weakly magnetic impurities. Module 2 contains the high-frequency STEINERT EddyC FINES eddy current separator with its unique eccentric and adjustable pole system for the separation of fine non-ferrous metals. The STEINERT FinesMaster reveals its greatest strength in the grain size range between 1 and 25 mm a range in which other systems have usually already exceeded their limits.

We succeeded in optimising the material feed by abandoning the use of separate conveyor technology. An upstream, weak-field magnetic drum initially extracts fine, clean iron from the material flow. The residual fraction from the first magnetic stage passes via a discharge directly onto a downstream, fast-running magnetic separator equipped with strong neodymium permanent magnets. The high supply speed significantly loosens the material flow and all weakly magnetic impurities can be removed by the magnetic head pulley. The removal of weakly magnetic impurities like ferrous dust, clumps and fluff reduces the volume to the downstream eddy current separator by up to 30%. The third sorting stage then optimally prepares the material for non-ferrous separation using eddy-current where it is efficiently performed.