Jul 14, 2020 The low-grade siliceous chromite ore from Ghutrigaon, Odisha, India, containing 16 Cr 2 O 3, with CrFe ratio of 1.97 and 55 of SiO 2, does not find any use in metallurgical industry and hence considered as waste.Mineralogical investigation indicates the presence of chromite and quartz as major minerals with minor fuchsite and kaolinite.
We investigated a method for delivering ferrous iron into the subsurface to enhance chemical reduction of CrVI in chromite ore processing solid waste COPSW derived from the production of ferrochrome alloy. The COPSW is characterized by high pH 8.5-11.5 and high CrVI concentrations in the sol
Modeling chromium leaching from chromite ore processing waste1.31 . In chromite ore processing residue-enriched soils and other aqueous environments, Cr VI is reduced to Cr III by elemental Fe such as steel and wood James, 1994 Powell et al, 1995 and
Sep 17, 2004 Chromate reduction in FeII-containing soil affected by hyperalkaline leachate from chromite ore processing residue. Journal of Hazardous Materials 2011 , 194 , 15-23. DOI 10.1016j.jhazmat.2011.07.067.
chromite ore processing residue COPR is important for chromate salt production. In this study, the leaching of valuable elements from the waste COPR was investigated. X-ray diraction XRD analysis showed that the COPR mainly contained periclase MgCr 2 O 4, magnesiochromite Fe, Mg Cr, Fe 2 O 4, Fe Cr, Al 2 O 4, and MgFeAlO 4
Mar 25, 2019 1. Introduction. Hexavalent chromium CrVI is highly mobile, severely toxic Shahid et al., 2017 and highly carcinogenic to humans .Chromite ore processing residue COPR is a type of hazardous industrial waste Mills et al., 2017 Moon et al., 2008 Wu et al., 2015 that contains a large amount of residual Cr 200040,000 mgkg.Furthermore, 30 of the total Cr comprising COPR is in ...
Jul 10, 2018 The processing cycle of Fe-Cr involves the chemical reduction of the chromite ore. Smelting of HC Fe-Cr ferro-alloy. HC Fe-Cr and charge chrome are normally produced by the conventional smelting process utilizing carbo-thermic reduction of chromite ore consisting oxides of Cr and Fe using an electric submerged arc furnace SAF or a DC ...
Apr 05, 2021 Chromite mineral processing is complicated by the variations in the chromite mineral spinel structure Mg 2, Fe 2O Cr 3, Al 3, Fe 3 2 O 3. The variations are brought about by the partial substitution of the divalent iron by magnesium and trivalent chromium by varying proportions of aluminium and ferric iron.
Cr 2 O 3 is reduced by solid C at temperatures 1250 C, although, in reality, Fe and Cr oxides do not occur in a free form in a chromite spinel, and therefore more extreme conditions might be required to achieve reduction. To minimize energy consumption, the preprocessing of the chromite feed material, such as pelletized oxidative sintering ...
Jul 20, 2017 The average grade of the metallurgical chromite ore was 43.4 pct Cr2O3, with 52 pct of the ore having a chromium-to-iron ratio of 31 or over, 17.6 pct having a ratio between 21 and 31, and 30.4 pct having a ratio less than 21. Chemical-grade chromite ore generally ranged from 40 to 46 pct Cr2O3 with a chromium-to-iron ratio of 1.51 to 21.
Description. Chromite is a mineral composed of natural oxide of ferrous iron and chromium, with varying amounts of magnesium and aluminum substituting for the iron and chromium. Formula Cr 2 FeO 4 or Cr
Nov 01, 2005 We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium CrVI in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate FeSO4 in combination with sodium dithionite Na2S2O4 to inhibit premature precipitation of Fe in the subsurface.
Jul 19, 2014 The CrFe 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 CrFe ratio has been reported.
Oct 30, 2011 Highly alkaline pH 12.2 chromate contaminated leachate 990 mol L-1 has been entering soils below a chromite ore processing residue disposal COPR site for over 100 years. The soil immediately beneath the waste has a pH of 1112.5, contains 0.30.5 ww chromium, and 4575 of the microbially available iron is FeII.
Jan 03, 2012 become imperative to improve the CrFe ratio along with Cr content of lowmedium grade ore resources 3-4. Various attempts have been made to improve the CrFe ratio of Indian chromite ores. The CrFe ratio of chromite concentrate was investigated by Murthy et al. and found that it can be improved up to 2.8 by using wet high intensity
Chromite ore processing residue COPR containing measurable levels of hexavalent and trivalent chromium. CrVI and CrIII, respectively has been used to fill in low-lying areas in Hudson County, N.J.
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The chromite ore CrFe ratio is of importance as it directly affects the alloy Cr grade whilst the gangue elements affect the melting energy and rate as well as the slag chemistry. The chromite spinel ore morphology can be described stoichiometrically as Fe, MgCr,Al,Fe2O4 and chromite ores often contain gangue elements of SiO2 and MgO.
Position 36 Mineral Chromite Sample Name Chr Type Oxide Nominal formula Fe2,MgCr,Al,Fe32O4 Supplier Cannon Microprobe, Seattle, WA Source G Zone ...
A process for the production of chromium nuggets from chromite oreconcentrate comprises - oxidizing chromite orechromium concentrate 1 comprising a Cr Fe-ratio ranging from 1.0 to 3.3 in a furnace 2 at a temperature of 900 C, - mixing 7 the oxidized ore 4 with reductant coal 5 and fluxes lime, silica 6, - pelletizing 8 the mixture, - reducing the pellets in a rotary ...
chromite processing crfe acmsa. Experiences in the production of J metallurgical and chemical chromite spinel Cr2O3 content and CrFe ratio. Experiences in the production of RULE, C.M. Energy considerations in the current PGM processing flowsheet Chromite Ore Processing Chromite Ore Beneficiation Plant Chromite Ore Processing Plant.
Mar 18, 2020 Chromite ore processing residue COPR is a waste derived from the chromate extraction from roasted ores and is deposited in some countries in landfills. The objective of this study was to investigate the leaching characteristics of hexavalent Cr CrVI from two COPR samples obtained from unlined landfills in the Kanpur area of northern India.
An Improved High-Throughput Data Processing Based on Combinatorial Materials Chip Approach for Rapid Construction of Fe-Cr-Ni Composition-Phase Map ACS Comb Sci . 2019 Dec 92112833-842. doi 10.1021acscombsci.9b00149.
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FeCr smelters utilizing the pelletized chromite pre-reduction process, was described by Kleynhans et al. 2017a, 2016, 2012 and Neizel et al. 2013. In this method, the degree of chromite pre-reduction is calculated using the following equation 1 The soluble Cr Sol Cr and Fe Sol Fe in Equation
Magnesium frequently substitutes for iron in chromite. A solid solution series exists between the mineral chromite FeCr 2 O 4 and the isomorphous mineral magnesiochromite MgCr 2 O 4.Intermediate specimens can be rich in iron Fe,MgCr 2 O 4 or magnesium Mg,FeCr 2 O 4.For convenience in communication, these minerals are often referred to collectively as chromite.
The CrFe 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 CrFe ratio has been reported.
Chromite ores are the only source of chromium. The majority of chromite ores are processed into an intermediate product called high carbon ferro-chrome, or charge chrome, an alloy containing 50 Cr, about 6-8 C, varying amounts of Si 0-4, depending on the process used, with the balance Fe.
4 4C Fe 2Cr 4 CO 2 and C CO 2 2CO. Carbon the reductant amount size type Ding 1997 used graphite bought from Aldrich Chemical. The weight ratio of graphite to chromite 40 Cr 2O 3, 24 Fe 2O 3 in the composite pellets was 0.21, which was about 10 in excess of the stoichiometric requirement for the reduction of Cr and Fe ...
Jul 15, 2005 We investigated a method for delivering ferrous iron into the subsurface to enhance chemical reduction of CrVI in chromite ore processing solid waste COPSW derived from the production of ferrochrome alloy. The COPSW is characterized by high pH 8.511.5 and high CrVI concentrations in the solid phase up to 550 mg kg-1 and dissolved phase 357 mg L-1.
The achievable CrFe ratio of the concentrates varies from 1.5 to 2.8 from a low-grade deposit with CrFe ratios of 0.5 to 1.0 by using gravity separation 4,10,11,12,13. There are few published data available about processing low-grade deposits or tailings in order to beneficiate chromite.
Mar 22, 2020 The CrFe ratio is one of the important factors that decides the end-use of the chromite mineral. For ferro-chrome CrFe should be 2.81 Cr2O3 48 min and for charge chrome CrFe
General Chromite Information Chemical Formula FeCr2O4 Composition Molecular Weight 223.84 gm Chromium 46.46 Cr 67.90 Cr 2 O 3 Iron 24.95 Fe 32.10 FeO Oxygen 28.59 O 100.00 100.00 TOTAL OXIDE
AbstractThe present work is part of an investigation towards the development of a process route for the extraction of metal values from slag, low grade ores and other oxidic materials such as spent refractories using molten salts in the temperature range 800950 C. The present paper focuses on the recovery of metal values, primarily Cr and Fe, from electric arc furnace slag and chromite ore.
Jul 14, 2020 In an average, the chromite ore sample from Ghutrigaon contains 16 Cr 2 O 3, 7.9 Fe 2 O 3, 55 Si, 8 Al 2 O 3, 7 MgO, 1 CaO and 2.5 loss of ignition LOI, having CrFe of 1.97 Table 3. High silica is attributed to quartz and clay, while Cr and Fe contents are contributed by chromite and fuchsite.