Microstructural Analyses of Cr(VI) Speciation in …
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 …
Pyrolysis Treatment of Chromite Ore Processing Residue by …
The pyrolysis treatment with biomass is a promising technology for the remediation of chromite-ore-processing residue (COPR). However, the mechanism of this process is still unclear. In this study, the behavior of pyrolysis reduction of Cr(VI) by cellulose, the main component of biomass, was elucidated. The results showed that the …
Simple and efficient selective extraction of lithium
The results shows that NaClO addition is the key to realize the selective extraction of lithium from the layered NCM structure under a non-acidic environment. Interestingly, the cracking and phase transition of spent cathode particles, which generally occur during electrochemical degradation, were also observed via NaClO oxidation in …
Mineral processing: leaching process of chromium and
The current strategy reports the recovery of precious group metals (PGMs) from Na 2 CO 3 roast of Saudi Arabian ophiolitic chromite ore at 1160 °C under atmospheric O 2.The influence of roasting temperature (960–1200 °C) and leaching agents (H 2 O, HCl, H 2 SO 4) and their concentrations on the recovery of PGMs was …
Extraction of Cu and Cr from a spent Cu–Cr catalyst: …
Zhang et al. (2010) reported the alkali leaching of mechanically activated chromite and it was observed that leaching efficiency of non-activated chromite was …
Chemical beneficiation of chromite ore to improve the …
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 …
Beneficiation of South African chromite tailings using
The chemical composition of the chromite tailings sample is shown in Table 1. Table 1 shows that the sample had a chromite content of 20.03% with silica as the major gangue measured at 33.50%. The iron oxide content assayed at 17.94%. The chromite content corroborates the research that was conducted by [4] which indicated that there is sufficient
Ecofriendly Selective Extraction of Vanadium from …
Conventional vanadium (V) extraction methods for vanadium-bearing slags create high chromium content discharge Cr(VI)-containing hazardous wastes. In this article, an ecofriendly magnesiation roasting-acid leaching method is proposed to selectively extract V from the slag. In the near-zero discharge process the generation of Cr(VI) is …
Sufficient extraction of Cr from chromium ore …
The chromite particles are generally larger than the overall particle size distribution of COPR, containing most of the Cr mass in areas that are greater than 20 …
Selective extraction of vanadium from chromium by pure [C
The maximum β V/Cr by pure [C 8 mim][PF 6] was 100.6 in case of pH 3.5.. The extraction mechanism could be the anion exchange between HV 10 O 27 3− and PF 6 −.. A novel approach to prepare ionic liquids with metal oxo-anions as counter anion.. Vanadate-loaded IL phase can be quantitatively stripped by KPF 6 and NaOH.. Pure [C …
Sufficient extraction of Cr from chromium ore processing
Chromium ore processing residue (COPR) is a hazardous waste generated during the production of chromate. Currently, approximately 10% of Cr 2 O 3 cannot be extracted after chromite sodium roasting and remains in COPR, wasting valuable Cr resources. In this study, Mg was selectively removed by using (NH 4) 2 SO 4 roasting in combination with …
Chromite- mineralogy and processing
Selective flotation is usually achieved in the acid pH range 1.5-6, selectivity sometimes being improved by the use of depressants, such as sodium fluoride and sodium fluosilicate. Several studies have also shown that the flotation behaviour of chromite can be modified by heat treatment, although the mechanism is complex.
Preparation of Superconcentrate and Chromium Powder from Chromite …
Non-traditional metallurgical technology of comprehensive processing of Sevan chromite (with a 43–46% Cr 2 O 3 content) is developed allowing chromium extraction from local chromite in the form of more expensive chromium powder. The process of increasing the reactivity of chromite concentrate (with a Cr 2 O 3 content of …
Investigation of electrochemical oxidation technology for selective
Selective oxidation of bromide using a three-electrode system and an electrolyzer, was applied to extract bromine from concentrated seawater. It was feasibility for selective oxidation of bromide at the anode potential between 1.0 V and 1.5 V (with respect to the standard hydrogen electrode, SHE).
A cleaner method for preparation of chromium oxide from chromite …
The results showed that the selective removal of 79.55% Mg from COPR could be achieved under the optimum (NH 4) 2 SO 4 roasting conditions (80 mmol (NH 4) 2 SO 4, 800 °C, 2 h). During the subsequent sodium roasting and acid leaching stages, the Cr extraction rate was 84.63% for the COPR direct roasting and 95.39% for the Mg …
Growing Trends in the Efficient and Selective Extraction of …
Off-line MISPE currently offers a more selective and sensitive extraction protocol when compared to traditional SPE protocols. The advancement of using MIPs as the stationary phase for chromatographic columns will create fast, efficient and selective extraction protocols to improve the analysis of biological specimens in toxicology …
Chromite
Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr 2 O 4.It is an oxide mineral belonging to the spinel …
Partitioning and Mobility of Chromium in Iron-Rich …
The residues of the sequential extraction are chemically resistant minerals such as chromite (see Figure 4) that are highly prone to incomplete dissolution by …
A novel reductive alkali roasting of chromite ores for …
A novel reduction reaction for extracting Cr 2 O 3 from chromite ores is demonstrated by excluding the formation of carcinogenic chromate (Cr 6+) intermediates.We have investigated in detail the underpinning high-temperature reduction reaction: FeCr 2 O 4 +Na 2 CO 3 +2[C]=[Fe]+Na 2 Cr 2 O 4 +3CO (g), which defines the …
Review of preferentially selective lithium extraction from …
Selective lithium extraction at the first step of the recovery process can effectively solve those puzzles. Since lithium leaching is a non-spontaneous reaction requiring additional energy to achieve, it is found that these methods can be divided into five ways according to the different types of energy driving the reaction occurring: (i ...
Deactivation mechanistic studies of copper chromite …
Selective hydrogenation of furfural to furfuryl alcohol is an important step along the route in the conversion of hemi-cellulosic materials to biofuels as listed in Fig. 1.High yield of furfuryl alcohol (>96%) has been achieved via liquid phase, batch hydrogenation using copper chromite (CuCr 2 O 4 ⋅CuO) as the catalyst, with or without …
(PDF) A Review of Chromite Ore Processing Residue (COPR): …
Chromite ore processing residue (COPR) is a waste byproduct of chromate production that contains high levels of hexavalent chromium (Cr[VI]). Although the high temperature chromite process was ...
Recovery of chromium by calcium-roasting, sodium …
For the chromite lump or for particles where the spinel phase was coated by a silicate phase, the leaching reaction of the spinel phase was strongly obstructed by the …
The extraction of vanadium from titanomagnetites and other sources
The vanadium mineral coulsonite, FeV 2 O 4 forms series with chromite, FeCr2 O 4 and magnetite, Fe 3 O 4. Most of the vanadium is produced from titanomagnetites either directly from titanomagnetite ores/concentrates or indirectly from the slag left from smelting titanomagnetite ores. Titanomagnetite ores are associated with …
Preparation of Superconcentrate and Chromium …
Non-traditional metallurgical technology of comprehensive processing of Sevan chromite (with a 43–46% Cr 2 O 3 content) is developed allowing chromium …
The extraction of vanadium from titanomagnetites and other sources
1. Introduction1.1. Vanadium properties and applications. Vanadium is primarily used as an additive to steel in the form of ferrovanadium (Moskalyk and Alfantazi, 2003).Around 85% of the vanadium produced globally is used for this purpose (Swinbourne et al., 2016).Only minor amounts of vanadium are needed for this purpose, with …
Study on Extraction of Iron From Chromite | Request PDF
Thus, a kinetic study concerning the selective removal of iron from chromite by carbochlorination by using Cl2+CO was conducted between 606 and 720°C with the addition of 5% (w/w) NaCl and ...
Chromite | Chromium Ore, Properties, Uses and Occurrence
Chromite is the most important ore of chromium. Crystals are uncommon, but when found they are octahedral. Chromite is usually massive or in the form of lenses and tabular bodies, or it may be disseminated as granules. It is sometimes found as a crystalline inclusion in diamond. Chromite is dark brown to black in color and can …
A cleaner method for preparation of chromium oxide from chromite
The indirect steel slag (SS)-based carbon capture, utilization, and storage (SS-based CCUS) process is recognized as a promising way for simultaneous mitigation of CO 2 emissions and valorization of wastes. Even so, much still needs to be done for sizeable and economic implementations of the SS-based CCUS process, such as …
Selective Flocculation of Chromite Tailings | Transactions …
Odisha state is the major reserve of the chromite ore. Due to the extensive applications, high-grade chromite ore is getting depleted day by day. Now it is a challenge for the industry to utilize these low-grade ores and tailings. Several attempts were taken to upgrade the low-grade chrome ores and tailings using different gravity separation …