Leaching of Valuable Elements from the Waste Chromite Ore . 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 temperatures.15 This residue contains a large amount of calcium and a small amount of iron, aluminum
MoreSodium 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 (Cr6+) from the waste residue has become a major problem for the
More2001-12-1 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 problem for the
More2021-6-17 Several researchers have used sodium carbonate with chromite ore in the soda-ash roasting reaction. Temperatures used are above 1073 K in air. The decomposition of sodium carbonate has resulted sodium oxide to react with chromium ion (Cr 3+) under an
More2016-10-1 Chromite ore and sodium carbonate are roasted at temperatures ranging between 900 °C and 1200 °C in oxidative atmosphere (Antony et al., 2001). Under these conditions, chromium is oxidised to Cr 6 + state, which then solubilises in water in the form of alkali chromate (e.g. Na 2 CrO 4 ).
More2021-12-9 [8] During the soda ash roasting, sodium carbonate is mixed with chrome ore and heated at a temperature above 800°C in air. The sodium oxide produced as a result of decomposition of sodium ...
More2017-1-14 Chromite ore and sodium carbonate are roasted at temperatures ranging between 900 °C and Fig. 1. World total output of titanium oxide based minerals and chromite ores and concentrates from 1971 to 2013. Brown et al. (2015). 214 S. Parirenyatwa et al. / Hydrometallurgy 165 (2016) 213–226.
MoreA method of producing sodium chromate from chromite ore which involves mixing the ore with sodium carbonate and a refractory diluent, pelleting the mixture at a temperature of at least 36° C. using a pelleting liquid which may be water or water containing dissolved substances, drying and roasting the pellets under oxidizing conditions, then disintegrating and extracting the pellets to
More2011-1-14 chromite ore and Na2CO3 are negative, and the standard Gibbs free energy changes of the reactions between MgO, Fe2O3 and SiO2 released from chromite spinel to form MgOFe 2 O 3 and MgOSiO 2 are also negative at the oxidative roasting temperatures (1 173−
More2019-6-11 (i) An ore (A) on roasting with sodium carbonate and lime in the presence of air gives two compounds, (B) and (C). (ii) The solution of (B) in conc. HCl on treatment with potassium ferricyanide gives a blue colour or ppt. of compound (D). (iii) The aqueous solution of (C) on treatment with conc. H 2 SO 4 gives a yellow coloured compound (E).
MoreSodium 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
More2018-3-20 molten phase formed during alkali roasting of chromite ore with sodium carbonate [12]. The liquid phase mainly consists on the formation of an eutectic mixture at 928 K between Na2CO3 and Na2CrO4 with a 62.5 wt.% sodium chromate.
MoreA method of producing sodium chromate from chromite ore which involves mixing the ore with sodium carbonate and a refractory diluent, pelleting the mixture at a temperature of at least 36* C. using a pelleting liquid which may be water or water containing dissolved substances, drying and roasting the pellets under oxidizing conditions, then disintegrating and extracting the pellets to
More2012-7-4 roasting (soda-ash roasting) of chromite ores. During the soda-ash roasting reaction, sodium carbonate is mixed with chrome ore and heated at a temperature above 1073 K in air. The sodium oxide produced a as result of the decomposition reaction of Na2CO3 reacts with the chromium ion (Cr 3+) of
More2017-10-18 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
MoreA method of producing sodium chromate from chromite ore which involves mixing the ore with sodium carbonate and a refractory diluent, pelleting the mixture at a temperature of at least 36° C. using a pelleting liquid which may be water or water containing dissolved substances, drying and roasting the pellets under oxidizing conditions, then disintegrating and extracting the pellets to
More2010-5-18 The production of chromate from chromite ore usually suffers from low extraction ratio and high environmental pollution. Traditionally, the chromite ore is processed by roasting with sodium carbonate at 1 200 ℃ in a rotary kiln with the addition of limestone and
MoreSodium chromate is commercially made by roasting a mixture of chrome ore, sodium carbonate and lime in a reverberatory furnace, and leaching the resulting mass. Chrome ore consists mainly of ferrous chromite (FeCr204) which during the roasting operation reacts with the sodium carbonate and oxygen to form carbon dioxide, ferric oxide, and the ...
MoreThe fusion of chromite ore (F e C r 2 O 4 ) with N a 2 C O 3 in air gives a yellow solution upon addition of water. Subsequent treatment with H 2 S O 4 produces an orange solution. The yellow and orange colours, respectively, are due to the formation of:
More2019-6-11 (i) An ore (A) on roasting with sodium carbonate and lime in the presence of air gives two compounds, (B) and (C). (ii) The solution of (B) in conc. HCl on treatment with potassium ferricyanide gives a blue colour or ppt. of compound (D). (iii) The aqueous solution of (C) on treatment with conc. H 2 SO 4 gives a yellow coloured compound (E).
More2017-10-18 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
More2012-7-4 roasting (soda-ash roasting) of chromite ores. During the soda-ash roasting reaction, sodium carbonate is mixed with chrome ore and heated at a temperature above 1073 K in air. The sodium oxide produced a as result of the decomposition reaction of Na2CO3 reacts with the chromium ion (Cr 3+) of
More2001-4-12 Soda-ash roasting of the chromite mineral is commonly used worldwide for the production of watersoluble sodium chromate. The formation of sodium chromate during the soda-ash roasting reaction depends on the oxygen partial pressure and availability of oxygen at the reaction front. The effects of temperature, oxygen partial pressure, charge composition, and
Moreinclude an oxidizing roast of the chro mite with sodium carbonate and lime in a rotary kiln at a temperature of 1,1000 to 1,1500 C. The amount of reagents and a diluent is controlled so that the reac tion mixture remains as a solid phase in the kiln (2). Concentrates that have been produced from domestic chromite de
More2004-11-19 The thermodynamic tendency of the reaction for FeOCr 2 O 3 is greater than that of traditional roasting of chromite ore with sodium carbonate (Na 2 CO 3), considering that the change of standard Gibbs free energy, Δ r G°, of Reaction 6 is −287.0 kJ/mol K 2 CrO 4 at 300° C, which is approximately twice as much as that of Reaction 1 in the ...
MoreThe fusion of chromite ore (F e C r 2 O 4 ) with N a 2 C O 3 in air gives a yellow solution upon addition of water. Subsequent treatment with H 2 S O 4 produces an orange solution. The yellow and orange colours, respectively, are due to the formation of:
More2019-6-11 (i) An ore (A) on roasting with sodium carbonate and lime in the presence of air gives two compounds, (B) and (C). (ii) The solution of (B) in conc. HCl on treatment with potassium ferricyanide gives a blue colour or ppt. of compound (D). (iii) The aqueous solution of (C) on treatment with conc. H 2 SO 4 gives a yellow coloured compound (E).
More2015-12-3 The interaction of nonferrous and iron sulfides with sodium and potassium carbonate is little -studied. Patent 4,541,993 (USA) offers joint sulphatization roasting of sulphide ores and carbonate or bicarbonate of alkali metals for extracting non-ferrous metals (copper, nickel, cobalt and zinc). Studies of the behavior of PbS, Cu 2 S, Bi 2 S 3 FeS 2
More2016-7-14 About 7 tons of fuel was consumed per 24 hr. for a rated furnace capacity of 120 tons of ore, which is equivalent to 117 lb. of coal per ton of ore roasted. The feed carried 3 to 4 per cent moisture, and the roasting temperature
More2021-5-7 The impurities must be removed from the ore prior to the extraction of the metal. The processes used for removing the gangue from the ore are based on the differences between the physical or chemical properties of the gangue and the ore. Different separation techniques are accordingly employed. 1. Extracting Metals Low in the Reactivity Series
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