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Chromite contains Mg, ferrous iron [Fe(II)], Al and trace amounts of Ti. [5] Chromite can change into different minerals based on the amounts of each element in the mineral. Chromite is a part of the spinel group, which means that it is able to form a complete solid solution series with other members in the
It is usually found as the mineral chromite, from which ferrochrome is produced in a smelting process. Rank Country/Region Chromium ore production (tonnes)
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 . The subsequent leaching at higher elevated temperatures dissolves the chromates and leaves the insoluble iron oxide.
Chromite (an oxide of Cr and Fe) is reduced by coal and coke to form the iron-chromium alloy. The heat for this reaction can come from several forms, but typically from the electric arc formed between the tips of electrodes in the bottom of the furnace and the furnace hearth. This arc creates temperatures of about 2,800 °C (5,070 °F).
The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide [1] [2]. Chromium compounds are compounds containing the element chromium (Cr). Chromium is a member of group 6 of the transition metals.
It is derived from the mineral chromite, (Fe,Mg)Cr 2 O 4. The conversion of chromite to chromia proceeds via Na 2 Cr 2 O 7, which is reduced with sulfur at high temperatures: [7] Na 2 Cr 2 O 7 + S → Na 2 SO 4 + Cr 2 O 3. The oxide is also formed by the decomposition of chromium salts such as chromium nitrate, or by the exothermic ...
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Group-I kimberlites are of CO 2-rich ultramafic potassic igneous rocks dominated by primary forsteritic olivine and carbonate minerals, with a trace-mineral assemblage of magnesian ilmenite, chromium pyrope, almandine-pyrope, chromium diopside (in some cases subcalcic), phlogopite, enstatite and of Ti-poor chromite. Group I kimberlites exhibit ...