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Roasting and leaching behaviors of vanadium and chromium

Calcification roasting-acid leaching of high-chromium vanadium slag HCVS was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium The effects of the purity of CaO molar ratio between CaO and V2O5 n CaO / n V 2 O 5 roasting temperature holding time and the heating rate used in the oxidation-calcification processes were investigated...

Recovery and Separation of Vanadium and Chromium by Two

selective leaching process could be achieved by enhancing the electric filed in the alkaline medium Therefore in this paper vanadium and chromium were separated and recovered by a two-step leaching process electro-oxidation leaching of vanadium and H 2 O 2 as well as oxidation leaching of chromium in an alkaline medium...

Green manufacturing process of chromium compounds

Nov 19 2004 0183 32 INTRODUCTION Chromium compounds are essential to many industries but their manufacturing process is usually a major source of pollution 1-4 In the traditional manufacturing process that uses oxidation roasting at a high temperature 1200 176 C water leaching and multistage evaporation crystallization 3 4 the utilization efficiency of resources and energy is quite low...

Highly Efficient Recovery of Vanadium and Chromium

to leach out vanadium and chromium Roasting-leaching is a common technology for vanadium extraction Vanadium in low valence is oxidized to sodium vanadate with the addition of sodium salt in sodium-roasting technology9 Also calcium-roasting technology has been applied to overcome some problems associated with sodium-roasting technology such as...

Recovery of chromium by calcium

Oct 20 2020 0183 32 Chromium is a major strategic mineral widely used in industrial processes yet mineral resources are decreasing calling for advanced recycling techniques to recover chromium from ores waste and contaminated media Here we review chromium resources and methods to leach out Cr such as calcium-roasting sodium-roasting acidic leaching alkaline leaching and sub-molten...

Chromium Cr

Jul 15 2013 0183 32 Chromium is mined as chromite ore Globally this ore is available in India South Africa Finland Zimbabwe Kazakihstan and the Philippin Commercially chromium is produced from chromite using silicothermic or aluminothermic reactions Roasting and leaching processes are also used Chemical Properties...

Process for extracting chromium from chromium ores

I claim 1 A process for extracting chromium in the form of a chromate from ore or concentrate by the suspension oxidation thereof to the chromate state which comprises suspending finely crushed ore or concentrate containing the chromium in a molten liquid bed of an alkali metal salt in the ratio of 1 part by weight of ore to 5 to 20 parts by weight of salt subjecting the suspension to...

PDF Sulfuric acid leaching of Turkish chromite concentrate

Dec 04 2020 0183 32 During the leaching process more than 90 of chromium could be leached out under optimal reaction conditions and the leaching temperature was much lower than roasting process...

A clean metallurgical process for separation and recovery

Nov 01 2018 0183 32 Effect of roasting time on the leaching of vanadium and chromium from the V-Cr-bearing reducing slag mixed with 60 wt H 2 SO 4 and 40 wt H 2 O roasted at 160 176 C for different time and then leached in 2 Na 2 SO 3 solution with L/S ratio 4 1 ml/g at 95 176 C for 1 h...

Simultaneous extraction of vanadium and chromium from

Currently sodium salt roasting is the most representative and the most widely used method for extracting of vanadium from the vanadium slag Wang et al 2014 and this process mainly consists of the following operation units salt roasting water leaching purification precipitation and V 2 O 5-calcination Ye 2006 During the salt roasting...

Investigation of efficient conditions for chromate

Jul 15 2004 0183 32 The highest extraction efficiency 962 of chromium in the chromite was obtained at 650 176 C and a fusion time of 60 min The weight ratio of NaOH to Cr 2 O 3 in chromite was 6/1 In methanol leaching 826 of the unreacted NaOH was recovered at 50 176 C a leaching...

Extraction Behavior of Vanadium and Chromium by

Additionally 068 chromium was co-leached achieving the separation of vanadium and chromium The roasting factors affecting vanadium extraction followed this order roasting temperature gt m CaO /m V 2 O 5 =holding time For the chromium extraction the interaction between m CaO /m V 2 O 5 and roasting temperature was significant...

Sequential extraction of vanadium and chromium from

The sequential extraction of vanadium and chromium from the chromium-bearing vanadium slag through two-stage soda roasting-water leaching was proposed The precipitation order and thermodynamic stability of Cr-spinel and V-spinel were thoroughly calculated with FactSage 63 software The mechanism of the sequential extraction process is further determined by X-ray diffraction XRD...

Extracting Chromium from Stainless Steel Slags by NaOH

An effective extraction of chromium from SSL slag might be a solution The conventional industrial process in chromium extraction from chromite involves adding Na 2 CO 3 to chromite during the sample roasting The authors found that if a similar process is used to extract chromium from SSL slag the chromium extraction was 33 at 800 176 C...

Influence of Silica on the Lime

The evolution of silica during the lime-free roasting and their roles were investigated using chromium-containing slag with high content of ferric oxide and silica The siliceous salt phases were analyzed by means of X-ray diffraction scanning electron microscope and energy-dispersive X-ray spectroscopy The reaction rule involved with silicon-containing compounds in the roasting process was...

Comparative study of alkali roasting and leaching of

Organic acid leaching Extraction of titanium and chromium oxides may be achieved via roasting the respective minerals with alkali at high temperatures followed by water and organic acid le aching In this study sodium and potassium hydroxides are used as alkali for roasting of chromite ores and ilmenit e mineral concentrat...

Leaching of hexavalent chromium from young chromite ore

ground and roasted chromite or In the roasting process insoluble trivalent chromium Cr III present in the ores oxidizes to soluble hexavalent Cr Cr VI which is then recovered by aqueous leaching for further processing Burke et al 1991 The technology dates back to 1845 and is still in...

Leaching of Valuable Elements from the Waste Chromite Ore

COPR vary depending on the roasting process The COPR from the calcium roasting process is the residue of water leaching after mixing chromite sodium carbonate Na 2 CO 3 and dolomite and calcining at high temperatur15 This residue contains a large amount of calcium and a small amount of iron aluminum chromium etc However the COPR...

Chromium Properties and Occurrences

Chromium is mined as chromite ore Globally this ore is available in India South Africa Finland Zimbabwe Kazakhstan and the Philippin Commercially chromium is produced from chromite using silicothermic or aluminothermic reactions Roasting and leaching processes are also used Information Source enwikipediaorg azom...

Green Manufacturing Process of Chromium Compounds

ing process that uses oxidation roasting at a high tem-perature 1200 176 C water leaching and multistage evaporation crystallization 3 4 the utilization effi-ciency of resources and energy is quite low Chromate plants discharge large amounts of chromium-contain-ing residues dusts and waste gas Chromium-con-...

Roasting and leaching behaviors of vanadium and chromium

May 01 2018 0183 32 Calcification roasting-acid leaching of high-chromium vanadium slag HCVS was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium The effects of the purity of CaO molar ratio between CaO and V2O5 n CaO / n V 2 O 5 roasting temperature holding time and the heating rate used in the oxidation-calcification processes were investigated...

A cleaner vanadium extraction method featuring non

Abstract A cleaner method featuring non-salt roasting and ammonium bicarbonate leaching has been studied for the extraction of vanadium from vanadium slag Compared to the traditional alkaline salt roasting followed by water leaching process chromium spinel in the raw vanadium slag will not be converted to carcinogenic chromate salts and exhaust gas will not be produced in the non-salt...

Effective Chromium Extraction from Chromium

produce sodium chromate in sodium roasting process8 9 During the chromium extraction process the recovery rate is controlled by the salt roasting step in which chromium species in high valence states such as sodium chromate are produced These compounds are readily soluble in the sub-sequent leaching step Therefore oxidation of chromite ores...

Physical Chemistry of Roasting and Leaching Reactions for

Traditionally chromium chemical extraction has been carried out with alkali and CaO roasting which led to major environmental issues due to CaCrO 4 /Na 2 CrO 4 release In this review we examine the physical chemistry of both the low- and high-temperature roasting processes which oxidizes the Cr...

PDF The Effect of Chromium on the Roasting Process of

We simulated the roasting process of chromium by mixing Cr2O3 and Na2CO3 to analyze the influence of chromium on roasting vanadium slag Samples were characterized by XRD thermal analysis and SEM...

Remediation of lime

May 29 2018 0183 32 2018 Remediation of lime-free roasting chromite ore processing residue COPR by water leaching and pyrolysis process Energy Sources Part A Recovery Utilization and Environmental Effects Vol 40 No 11 pp 1417-1425...

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