Green metallurgical processing of chromite
Thermodynamically, the reaction of FeO·Cr 2 O 3 with sub-molten potassium hydroxide is much more favorable than with sodium carbonate in the traditional roasting of chromite. The change of standard Gibbs free energy, Δ r G o, is much lower than that of the traditional roasting process.
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Formation of Chromium-Containing Molten Salt Phase
Previous investigations reported that when chromite is roasted with soda-ash, a molten salt containing chromium, which is mainly composed of sodium carbonate and sodium chromate (Na2CO3-Na2CrO4 ...
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Kinetics of chromite ore in oxidation roasting process
Chromium salt manufacturing is a typical extraction process, which takes chromite, sodium carbonate, and dolomite as raw materials. After high-temperature oxidation roasting, chromium oxides are ...
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Chemistry of Chromium
If you add sodium carbonate solution to a solution of hexaaquachromium(III) ions, you get exactly the same precipitate as if you added sodium hydroxide solution or ammonia solution. This time, it is the carbonate ions which remove hydrogen ions from the hexaaqua ion and produce the neutral complex.
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(PDF) Preparation of Industrial Sodium Chromate …
The oxidation reaction of chromite by molten sodium salts was studied in the temperature range of 270N3500C. The grain size of chromite ores were kept constant through-out the reaction period, and ...
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When a chromite ore (A) is fused with sodium carbonate in …
Identify compounds (A) to (D) and also explain the reactions involved. View Solution. When an oxide of manganese (A) is fused with KOH in the presence of an oxidising agent and dissolved in water, it gives a dark green solution of compound (B). ... Fusion of chromite ore with sodium carbonate in excess of air gives a compound (X) (yellow ...
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Sodium Carbonate | Na2CO3 | CID 10340
Sodium Carbonate | Na2CO3 or CNa2O3 | CID 10340 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more. ... This reaction is accelerated by carbonic anhydrase, an enzyme present in high concentrations in red blood cells.
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When a chromite ore (A) is fused with sodium carbonate in …
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C ) …
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The soda-ash roasting of chromite ore processing residue for …
Sodium chromate is produced via the soda-ash roasting of chromite ore with sodium carbonate. After the reaction, nearly 15 pct of the chromium oxide remains unreacted and ends up in the waste ...
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(PDF) Processing of Chromite Overburden by …
Sodium chromate is produced via the soda-ash roasting of chromite ore with sodium carbonate. After the reaction, nearly 15 pct of the chromium oxide remains unreacted and ends up in the waste ...
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Sodium Chromate Formula: Structure, Preparation, …
Sodium chromate is produced commercially by roasting chromium ores in air in the presence of sodium carbonate. The most common chromium ore is chromite ((FeCr_2O_4)). The roasting process converts the chromium into a water-extractable form, leaving behind iron oxides. The following chemical equation represents the roasting …
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Explain the manufacture of potassium dichromate from chromite …
The manufacturing of potassium dichromate from chromite ore involves three steps. The first step is the reaction of chromite ore with sodium carbonate $left( {{text{N}}{{text{a}}_{text{2}}}{text{C}}{{text{O}}_{text{3}}}} right)$ in excess of oxygen. Instead of sodium carbonate potassium carbonate can also be used. The reaction is …
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PRODUCTION AND CONTROL OF SODIUM …
500kg of chromite was crushed and entered the roaster with sodium carbonate to produce chromate by the reaction: 2Cr 2 O 3 + 4Na 2 CO 3 + 3O 2→ 4Na 2 Cr O 4 + 4CO 2 (1) The produced chromate entered CSTR reactor with a sulfuric acid (98%) to produce dichromate by the reaction: 2Na 2 Cr O 4 + H 2 SO 4 → Na 2 Cr 2 O …
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Preparation of Potassium Dichromate and …
Dichromates are usually prepared from chromates and this is obtained by the combination of chromite ore with sodium/potassium carbonate in the presence of air. Potassium Dichromate. The reaction can be given as: …
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A novel reductive alkali roasting of chromite ores for …
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 …
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The soda-ash roasting of chromite ore processing residue for …
Sodium chromate is produced via the soda-ash roasting of chromite ore with sodium carbonate. After the reaction, nearly 15 pct of the chromium oxide remains unreacted and ends up in the waste stream, for landfills. In recent years, the concern over environmental pollution from hexavalent chromium (Cr 6+ ) from the waste residue has become a major …
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Preparation of Potassium Dichromate Crystals from the Chromite …
In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 °C in the microwave oven (frequency: 2.45 GHz; …
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How is potassium dichromate prepared from a sample of chromite …
Chromites have reactions with many gases such as [CO] and [C{O_2}]. Due to its structure it is highly stable in nature. Let's observed preparation of potassium dichromate from a sample of chromite ore: Chromite ore is in the form of powdered and it is firstly heated with the sodium carbonate in the presence of air.
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PRODUCTION AND CONTROL OF SODIUM …
Chromite is crushed, roasted with soda ash to produce sodium chromate. Sodium chromate are to be reacted with concentrated sulphuric acid to produce sodium …
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When a chromite ore (A) is fused with sodium carbonate in …
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution.
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Electrochemical enhanced oxidative decomposition of chromite …
1. Introduction. Chromate production from chromite ore is an important metallurgical process but is also a source of major pollution. In the traditional chromate production process, chromite ore is calcined with sodium carbonate at 1200 °C in a rotary kiln with the addition of limestone and dolomite.Due to the poor mass transfer efficiency …
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Reaction between chromium(III) oxide and oxygen in the …
The large scale manufacture of sodium chromate is carried out by heating finely ground chromite ore mixed with sodium carbonate and lime in air. The essential reaction leading to the formation of sodium chromate is $$2Cr_2 O_3 + 4 Na_2 CO_3 + 3 O_2 xrightarrow{{Delta {rm H}_{R^0 } }}4Na_2 CrO_4 + CO_2 $$
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Thermodynamics of chromite ore oxidative roasting …
Sodium carbonate is the most important reactant in the roasting process and its reaction rules will affect the roasting process directly. Under the conventional lime-free roasting conditions, sodium carbonate not only reacts with chromite spinel but also reacts with the impurities present in chromite ore. Among them, the reactions of sodium ...
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The Study of the Factors Affecting The Formation Of …
Formation Of Sodium Chromate From Chromite ... the sodium carbonate mole ratio used was indicated to be 75 kg/cm. 2 ... or maximum reaction rate and maximum product formation thereafter for
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Comparative study of alkali roasting and leaching of …
In this process, the extraction of chromium is achieved via roasting the mineral with alkali salts (usually sodium carbonate). Chromite ore and sodium carbonate are …
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(a) Sodium carbonate on reaction with hydrochloric acid in …
Write the balanced chemical equations for the following reactions:a Sodium carbonate on reaction with hydrochloric acid in equal molar concentrations gives sodium chloride and sodium hydrogen carbonate.b Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water liberates carbon dioxide.c Copper sulfate on …
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The Soda-Ash Roasting of Chromite Minerals: Kinetics …
Pressed pellets of sodium carbonate mixed with chromite The flow rate of gas through the reaction chamber was ore were used for the thermogravimetric analysis (TGA) maintained at 250 mL?min 21 .
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Sodium Carbonate
Sodium carbonate (Na2CO3) also known as washing soda or soda ash is a sodium salt of carbonic acid. It is generally prepared by ammonia soda or Solvey process. ... In this process carbon dioxide and ammonia are passed into a cold saturated solution of sodium chloride. In the reactions which occur sodium hydrogen carbonate is formed which is ...
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Mineral processing: leaching process of chromium and …
Four chromite samples (120–180 ± 0.01 g) were roasted with sodium carbonate in clay crucibles at about 1160 °C in air for 2 h. Iron in chromite roast reacts with sodium carbonate to produce NaFeO 2 + NaAlSiO 4 and other complex sodium-aluminium silicate according to the following reaction [1, 26]:
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