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roasting leaching chromium

A green method to leach vanadium and chromium from …

2018-1-11 · Hydrogen peroxide as an oxidant was applied in leaching of vanadium and chromium in concentrated NaOH solution. Under the optimal …Industrialized application of high efficient extraction of ...2019-8-12 · The leaching rates of vanadium and chromium were 93.68% and 96.76%. When the concentration of chromium in solution reaches 25~30 g/L, the crystallization process of sodium chromate can ensure that all the chromium dissolved in each liquid phase oxidation reaction was precipitated, and the crystallization rate of sodium chromate was 17.65%.

A novel roasting process to extract vanadium and …

Under the optimum microwave roasting conditions (1 NaOH/NaNO 3 mass ratio, 450 ℃ roasting temperature, and 10 min roasting time), the leaching rates of vanadium and chromium were 94.11% and 90.81%, respectively. In the leaching process, the reaction mechanism for the water leaching process was proposed.Selective Recovery of Chromium From Ferronickel Slag via .. romium was selectively recovered from ferronickel slag by roasting the slag with addition of Na 2 O 2, followed by water leaching.The thermodynamic analysis revealed that in the presence of Na 2 O 2 at appropriate temperatures, the Cr 2 O 3 in the ferronickel slag can be converted to NaCrO 2, instead of Na 2 CrO 4, which prevents the formation of highly toxic Cr (VI).

Effective Extraction of Vanadium and Chromium from High ...

The roasting parameters have been studied as a function of roasting temperature, roasting time and ratio of alkali, in which the roasting temperature is the most effective factor on the leaching rate of vanadium and chromium. Under the …The Effect of Chromium on the Roasting Process of …2017-5-7 · the influence of chromium on roasting vanadium slag. Samples were characterized by XRD, thermal analysis and SEM at different temperatures: Cr2O3 and Na2CO3 began to react at 500 C. When the chromium oxide content was about 3.2%, the conversion rate of V reached the maximum value of 95%. Keywords: vanadium slag; roasting; chromium 1. Introduction

Roasting and leaching behaviors of vanadium and …

2017-9-13 · 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 V 2 O 5 ( n (CaO)/ n (V 2 O 5 )), roasting temperature, holding time, and the heating rate used in the oxidation–calcification …Roasting and leaching behaviors of vanadium and …When leaching temperature and leaching time are 100 ºC and 120 min, the optimic leaching ratio of vanadium and chromium are 95.92%, 4.27% after microwave roasting and 84.96%, 2.15% after ...

Roasting and leaching behaviors of vanadium and …

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 parative study of alkali roasting and leaching of ...roasting at moderately high temperatures followed by leaching at low temperatures has been investigated for the treatment of titanium oxide minerals and chromium ores.

Reclamation of reactive metal oxides from complex …

this context, alkali roasting and leaching as a novel approach for alumina, chromium oxide, titanium dioxide, rare-earth and vanadium pentoxide recovery is presented and discussed with examples for the separation of metal values. 2. Industrial history Louis Le Chatelier, in 1887, investigated the oxidative roastingIndustrialized application of high efficient extraction of ...2019-8-12 · The leaching rates of vanadium and chromium were 93.68% and 96.76%. When the concentration of chromium in solution reaches 25~30 g/L, the crystallization process of sodium chromate can ensure that all the chromium dissolved in each liquid phase oxidation reaction was precipitated, and the crystallization rate of sodium chromate was 17.65%.

Preventing Chromium Leaching

2018-8-19 · In this case, high chromium leachability is desired and is aided by the addition of lime to a mixture of chromite ore and Na2CO3. The CaO-Na2CO3 ore mixture is roasted at 1,100° to 1,150° C in an oxidizing air atmosphere, followed …The Effect of Chromium on the Roasting Process of …2017-5-7 · the influence of chromium on roasting vanadium slag. Samples were characterized by XRD, thermal analysis and SEM at different temperatures: Cr2O3 and Na2CO3 began to react at 500 C. When the chromium oxide content was about 3.2%, the conversion rate of V reached the maximum value of 95%. Keywords: vanadium slag; roasting; chromium 1. Introduction

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2021-6-17 · Leaching Kinetic of Vanadium from Calcium-roasting High-Chromium Vanadium Slag Enhanced by Electric Field. ACS Omeg a, 2020, 5 (28): 17664 – 17671. 7. Hao Peng*, Qian Shang, Ronghua Chen, Liuying Zhang, Ya Chen, Jing Guo. Step-Adsorption of 8 dustrialized application of high efficient extraction of ...2019-8-12 · The leaching rates of vanadium and chromium were 93.68% and 96.76%. When the concentration of chromium in solution reaches 25~30 g/L, the crystallization process of sodium chromate can ensure that all the chromium dissolved in each liquid phase oxidation reaction was precipitated, and the crystallization rate of sodium chromate was 17.65%.

Leaching of hexavalent chromium from young chromite …

2020-6-1 · ground and roasted chromite ores. 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 inTwo Step Roasting And Leaching Process9For the production of pure chromium the iron must be separated from the chromium in a two step roasting and leaching process the chromite ore is heated with a mixture of calcium carbonate and sodium carbonate in the presence of air the chromium is oxidized to the hexavalent form while the iron forms the stable fe 2 o 3.

Effective Chromium Extraction from Chromium-containing ...

Chromium slags without vanadium were synthesized in the laboratory to mimick mineralogical characteristics of Pan-steel vanadium slag and characterized by XRD, SEM/EDS and TG-DSC techniques. Conditions for Cr extraction from the chromium slag after sodium roasting by leaching with water were studied and optimized.Highly efficient oxidation of chromium (III) with hydrogen ...2019-1-15 · Many technologies have been proposed to oxidize chromium, such as roasting-water leaching technology and hydrometallurgical methods such as pressure oxidative leaching coupled with oxygen, ozone, permanganate and ferrate, but the problems associated with the high temperature, low overall resource utilization efficiency, high energy consumption, and the …

Sulfation–Roasting–Leaching–Precipitation Processes for ...

2019-6-24 · 2.2. Sulfation–Roasting–Leaching–Precipitation Sulfation–roasting–leaching–precipitation (SRLP) is a combination of four consecutive and complementary processes. The original sample was first crushed and passed through 500 m and 100 m sieves to obtain two samples (+100–500 m and 100 m). As described by Borra et al.,The Chromothermic Reduction of Chromite2011-1-15 · addition of16,5 percent, but with 17,5 percent chromium the roasting time is down to 40 minutes. The decrease III roasting period through addition of excess chromium practically ceases with additions beyond about 17,5 per cent. The excess chromium metal remains unreacted and is lost during leaching. Similar proportional savings in the roasting ...

A novel roasting process to extract vanadium and …

Under the optimum microwave roasting conditions (1 NaOH/NaNO 3 mass ratio, 450 ℃ roasting temperature, and 10 min roasting time), the leaching rates of vanadium and chromium were 94.11% and 90.81%, respectively. In the leaching process, the reaction mechanism for the water leaching process was proposed.Effective Chromium Extraction from Chromium …Effects of roasting temperature, roasting time and addition amount of soda on the conversion rate were investigated by one-factor experimental designation. Optimization of chromium extraction from leaching liq-uids was also investigated. Leaching liquids with five dif-ferent chromium concentrations were acidified by sulfuric

A novel reductive alkali roasting of chromite ores for ...

2021-8-6 · 2 38 1). Introduction 39 40 1.1 Oxidative process chemistry of chromite roasting in the presence of alkali 41 Chromium is an important metallic element, known for high and low temperature 42 corrosion and oxidation-resistance properties, which the element imparts to the stainless 43 steel and superalloys [1]. Other usages of chromium are in the production of …A green method to leach vanadium and chromium from …2018-1-11 · Hydrogen peroxide as an oxidant was applied in leaching of vanadium and chromium in concentrated NaOH solution. Under the optimal …

Comparative study of alkali roasting and leaching of ...

2016-10-1 · 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 leaching. In this study, sodium and potassium hydroxides are used as alkali for roasting of chromite ores and ilmenite mineral concentrates.Preventing Chromium Leaching2018-8-19 · In this case, high chromium leachability is desired and is aided by the addition of lime to a mixture of chromite ore and Na2CO3. The CaO-Na2CO3 ore mixture is roasted at 1,100° to 1,150° C in an oxidizing air atmosphere, followed by water leaching of the roasted material to extract the chromium as Na2CrO4 in solution.

Effective Extraction of Vanadium and Chromium from High ...

The roasting parameters have been studied as a function of roasting temperature, roasting time and ratio of alkali, in which the roasting temperature is the most effective factor on the leaching rate of vanadium and chromium. Under the …Step-Adsorption of Vanadium (V) and Chromium (VI) in …2020-4-14 · The common methods for leaching out vanadium and chromium were hydrometallurgical technologies, like sodium salt roasting-water leaching 16, calcium roasting-acid leaching 17,18,19, molten ...

Physical Chemistry of Roasting and Leaching Reactions for ...

The natural resource of chromium is the chromite ore, which is a spinel (Fe 2+, Mg)[Cr,Al,Fe 3+] 2 O 4, and is often present with gangue minerals such silicates. 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.A novel roasting process to extract vanadium and …Under the optimum microwave roasting conditions (1 NaOH/NaNO 3 mass ratio, 450 ℃ roasting temperature, and 10 min roasting time), the leaching rates of vanadium and chromium were 94.11% and 90.81%, respectively. In the leaching process, the reaction mechanism for the water leaching process was proposed.

Selective recovery of chromium from ferronickel slag via ...

Chromium was selectively recovered from ferronickel slag by roasting the slag with addition of Na 2 O 2, followed by water leaching.The thermodynamic analysis revealed that in the presence of Na 2 O 2 at appropriate temperatures, the Cr 2 O 3 in the ferronickel slag can be converted to NaCrO 2, instead of Na 2 CrO 4, which prevents the formation of highly toxic Cr (VI).Extraction of chromium from tannery sewage sludge ...2022-2-10 · In the present research, the extraction of chromium from the tannery sewage sludge was investigated through the process of blank roasting-sodium carbonate roasting-water leaching and the process of sulfuric acid curing-water leaching, respectively.

Leaching of Vanadium and Chromium from Residue

2019-2-15 · and chromium, like salt-roasting, hypochlorite leaching, acid leaching, alkali leaching, ammonia leaching and bioleaching [3,4,10-14]. The present work was focused on the leaching process of vanadium and chromium from residue. The residue was formed in the treatment procedure for the wastewater containing Cr 6+ and V5+ in some iron and steel ...Effective Extraction of Vanadium and Chromium from High ...The roasting parameters have been studied as a function of roasting temperature, roasting time and ratio of alkali, in which the roasting temperature is the most effective factor on the leaching rate of vanadium and chromium. Under the …

Extraction of chromium from tannery sewage sludge ...

2022-2-10 · In the present research, the extraction of chromium from the tannery sewage sludge was investigated through the process of blank roasting-sodium carbonate roasting-water leaching and the process of sulfuric acid curing-water leaching, respectively.Efficient separation of chromium and vanadium by ...2019-8-1 · Calcification roasting–sodium carbonate (Na 2 CO 3) leaching process was carried out to separate chromium and vanadium efficiently from high chromium vanadium slag (HCVS).Then vanadium existed in the form of ammonium metavanadate (NH 4 VO 3) after precipitation from the purified leaching liquid, and highly pure V 2 O 5 was prepared, while chromium remained in …

Reclamation of reactive metal oxides from complex …

this context, alkali roasting and leaching as a novel approach for alumina, chromium oxide, titanium dioxide, rare-earth and vanadium pentoxide recovery is presented and discussed with examples for the separation of metal values. 2. Industrial history Louis Le Chatelier, in 1887, investigated the oxidative roastingA novel reductive alkali roasting of chromite ores for ...2021-8-6 · 2 38 1). Introduction 39 40 1.1 Oxidative process chemistry of chromite roasting in the presence of alkali 41 Chromium is an important metallic element, known for high and low temperature 42 corrosion and oxidation-resistance properties, which the element imparts to the stainless 43 steel and superalloys [1]. Other usages of chromium are in the production of …

Leaching of hexavalent chromium from young chromite …

2020-6-1 · ground and roasted chromite ores. 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 inStep-Adsorption of Vanadium (V) and Chromium (VI) in …2020-4-14 · The common methods for leaching out vanadium and chromium were hydrometallurgical technologies, like sodium salt roasting-water leaching 16, calcium roasting-acid leaching 17,18,19, molten ...

Efficient separation of chromium and vanadium by ...

2020-1-2 · Calcification roasting–sodium carbonate (Na 2 CO 3) leaching process was carried out to separate chromium and vanadium efficiently from high chromium vanadium slag (HCVS).Then vanadium existed in the form of ammonium metavanadate (NH 4 VO 3) after precipitation from the purified leaching liquid, and highly pure V 2 O 5 was prepared, while chromium remained in …Effective Chromium Extraction from Chromium …Effects of roasting temperature, roasting time and addition amount of soda on the conversion rate were investigated by one-factor experimental designation. Optimization of chromium extraction from leaching liq-uids was also investigated. Leaching liquids with five dif-ferent chromium concentrations were acidified by sulfuric

Selective Recovery of Chromium From Ferronickel Slag via ...

Chromium was selectively recovered from ferronickel slag by roasting the slag with addition of Na 2 O 2, followed by water leaching.The thermodynamic analysis revealed that in the presence of Na 2 O 2 at appropriate temperatures, the Cr 2 O 3 in the ferronickel slag can be converted to NaCrO 2, instead of Na 2 CrO 4, which prevents the formation of highly toxic Cr (VI).Study on leaching kinetics of hexavalent chromium from ...The leaching kinetic model is established based on the shrinking core model, and the precipitation mechanism of hexavalent chromium in the aged chromium slag is explored to provide a scientific basis for increasing the production of chromate in the roasting kiln; and to provide technical guidance for reducing the risk of environmental pollution.

Microwave Roasting and Acid Leaching of Vanadium and ...

Comparative study of alkali roasting and leaching of chromite ore…Roasting and leaching behaviors of vanadium and …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 V 2 O 5 (n(CaO)/n(V 2 O 5)), roasting temperature, holding time, and the heating rate used in the oxidation–calcification processes were investigated.

Step-Adsorption of Vanadium (V) and Chromium (VI) in …

2020-4-14 · The common methods for leaching out vanadium and chromium were hydrometallurgical technologies, like sodium salt roasting-water leaching 16, calcium roasting-acid leaching 17,18,19, molten ... - yznu2017-6-14 · Leaching Kinetic of Vanadium from Calcium-roasting High-Chromium Vanadium Slag Enhanced by Electric Field. ACS Omega, 2020, 5 (28): 17664–17671. 7. Hao Peng*, Qian Shang, Ronghua Chen, Liuying Zhang, Ya Chen, Jing Guo. Step-Adsorption of 8.