Theoretically it contains 46.5%Cr and 25.8%Fe and their oxides. The technology of obtaining chromite is based on the principle of gravity separation and agglomeration.
1. Introduction. Chromite ore processing residue (COPR) is an industrial waste generated during the extraction of Cr(VI) from chromite ore using the high-temperature lime-based roasting process [[1], [2], [3]].When COPR undergoes weathering reactions during the deposition process, it would release highly toxic and mobile Cr(VI) …
Chromite is an oxide mineral belonging to the spinel group, a complex mineral containing magnesium, iron, aluminum, and Cr in varying proportions, depending on the deposit, that can be represented as FeCr 2 O 4 or (Fe 2+,Mg)[Cr,Al,Fe 3+] 2 O 4 (Murthy et al., 2011; Sanchez-Segado et al., 2015).
Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work for generating an experimental dataset for …
1. Introduction. The natural mineral chromite is widely utilized by high-lime roasting technique to obtain chromate products due to the needs of leather, catalysis, metallurgy and other industries, in which a large amount of chromite ore processing residue (COPR) is produced (Dermatas et al., 2006; He and Traina, 2005).A small …
The Cr/Fe ratio of chromite can be influenced by various factors, including the composition of the host rock, the degree of alteration, and the presence of other minerals. ... Mining and processing of chromium (Cr) ore involves several stages, including extraction, beneficiation, and smelting. Here's an overview of the typical process for ...
X-ray absorption near-edge structure and density functional theory analyses reveal that coexisting Fe in the solid plays a critical role in the pH-dependent release and transformation of Cr(III), where …
Direct reduction of chromite (DRC) is a promising alternative process for ferrochrome production with the potential to significantly reduce energy consumption and greenhouse gas emissions compared to conventional smelting. In DRC, chromium (Cr) and iron (Fe) from chromite ore incongruently dissolve into a molten salt, which facilitates mass …
Chromite ore beneficiation: prospects and challenges. C. Raghu Kumar, ... Sharath Kumar Bhoja, in Mineral Processing, 2023. 3.4 Characterization. Chromite is a member of the spinel group of minerals and consists essentially of ferrous and chromic oxides—FeO, Cr 2 O 3, analogous to aluminates.Ferrous oxide is, however, often partly replaced by …
Our study provides a new insight into Cr (VI) reoccurrence in rCOPR and helps in predicting its environmental risk in nature. Keywords: Cr (III)−Fe (III) hydroxides; …
In the paper are shown the history, processing and applications of chromite. Chromite is an oxide of iron and chromium with the chemical composition FeO.Cr2O3 and belonging to the spinel group.
1. Introduction. Hexavalent chromium (Cr(VI)) is highly mobile, severely toxic (Shahid et al., 2017) and highly carcinogenic to humans (IARC, 2010).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 …
Overview of chromite ore processing. Chromite ore FeO·Cr 2 O 3 is a major ore for Chromium. India accounts for about 10% of world share of shipping grade Chromium ore reserves, having 45% Cr 2 O 3 content. South Africa and Zimbabwe and India are the Top five countries of Chrome ore processing industries in the Word …
The iron and a series of Fe-Cr alloys, listed in Table 1, were produced in button form having 24 mm diameter and 9 mm thick from appropriate weights of interstitial free (IF) steel and Fe-35Cr master alloy by using a laboratory vacuum arc melter (Edmund ™ make AM200).The ingot buttons were remelted four to five times in the melter …
The smelting behavior of waste chromite ore fines containing Cr and Ni to produce crude Fe–Cr–Ni–N alloy was investigated in this study. In the experiments, for each heat, liquid steel melt (metal pool 1 kg) was prepared in a 3--capacity laboratory-scale electric arc furnace for the absorption of reduced metals like chromium, nickel, etc., …
The Cr/Fe ratio of chromite can be altered by metalising and leaching Fe. •. Chromite spinel was altered through oxidation, making Fe-oxide more reducible. •. Cr/Fe …
The Fe content in the FeCr produced depends on the chromite spinel Cr/Fe ratio. Therefore, the selective removal of Fe from the chromite spinel using different combinations of chromite pre-oxidation, pre-reduction, and sulphuric acid leaching was investigated. The Cr/Fe ratio of the case study ores could be increased from 1.57 up to …
In the DRC process, Fe and Cr oxides in chromite are reduced at temperatures below their latent heat of fusion which substantially lowers energy requirements, resulting in the production of M 7 C 3-type ferrochrome. In the present work, induration by oxidative sintering, reductant size, and reduction temperature were …
Chromite ore processing residue (COPR) has been a severe environmental contaminant which is worthy of attention. In this study, we developed an eco-friendly and …
Request PDF | On Feb 1, 2023, Hong Tian and others published Efficient reduction of Cr(VI) and recovery of Fe from chromite ore processing residue by waste biomass | Find, read and cite all the ...
Forty percentage of Indian chromite reserves are suitable for metallurg ical use (Cr:Fe>2.8), 33% for refractory making (Cr:Fe of 2.8-1.8) and 27% fo r chemical industries (Cr:Fe <1.8)[1-2 ]. There is heavy demand for metallurgical grade chromite ore due to rap id growth o f steel industry and limited availability of such high-grade ore resources.
The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro …
Effect of Coexisting Fe(III) (oxyhydr)oxides on Cr(VI) Reduction by Fe(II)-Bearing Clay Minerals. Environmental Science & Technology 2019, ... Leaching kinetics of acid-soluble Cr(VI) from chromite ore processing residue with hydrofluoric acid. Journal of Central South University of Technology 2011, 18, 399-405. DOI: 10.1007/s11771-011 …
DOI: 10.1016/j.eti.2023.103046 Corpus ID: 256607791; Efficient reduction of Cr(VI) and recovery of Fe from chromite ore processing residue by waste biomass @article{Tian2023EfficientRO, title={Efficient reduction of Cr(VI) and recovery of Fe from chromite ore processing residue by waste biomass}, author={Hong Tian and Lanbin …
The chromite mineral phase in COPR has a formula of (Fe, Mg)Cr 2 O 4, it is difficult to determine the exact portion of substituted Fe(II) in chromite, thus we studied the contribution rate of Cr(III) and sulfuric acid to Mn leaching by using pure chromium oxide (Cr 2 O 3) to eliminate the influence of existed Fe(II). The contribution rate of ...
As our working hypothesis, it is contemplated that the CaCl 2-assisted DRC process involves incongruent dissolution of chromite in molten CaCl 2 followed by in situ reduction and metallization of Fe and Cr species on solid carbon particles. 8−10 There are, however, significant gaps in knowledge on the kinetics and mechanism of the DRC …
The achievable Cr:Fe ratio of the concentrates varies from 1.5 to 2.8 from a low-grade deposit with Cr:Fe 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.
Chrome ore chemical beneficiation One of the purposes of chemical beneficiation is to increase the Cr/Fe ratio of the chromite concentrate produced by the physical methods, and the other purpose is to treat certain chromium ores that cannot be treated by physical methods or that are uneconomical by physical methods.. The …
The optimum process conditions are as follows: the mixing ratio of stainless steel dust to chromium containing slag is 94%: 6%, the reduction temperature is 1400°C, the reduction time is 25 min ...
richment (i.e., increased Cr:Fe ratio) of a chromite sample from the Aladag concentrator, Turkey using a high-intensity dry magnetic separator resulted in a product with 49.1wt%