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The natural reserves of chromite in the Earth's crust exceed 1.8 billion tons, and the recoverable reserves exceed 810 million tons. In 2004, the world production of chromite was 17.5 million tons, of which 7.63 million tons were mined in South Africa, 3.27 million tons in Kazakhstan, 2.95 million tons in India, 670,000 tons in Zimbabwe, and 580,000 tons in Finland. China's chromium ore resources are relatively poor, according to the degree of meeting the demand, is a shortage of resources. Total reserves of ore 10.78 million tons, of which rich ore accounted for 53.6%. There are 56 chromium ore deposits, distributed in 13 provinces (autonomous regions) such as Tibet, Xinjiang, Inner Mongolia and Gansu, with Tibet as the most important, with reserves accounting for about half of the country. Chromium deposits in China are typical magmatic deposits related to ultrabasic rocks, most of which belong to the ophiolite type and occur in the ophiolite belt. Tibet Lubsha chromium ore and Xinjiang Saltuohai chromium ore are of this kind. From the perspective of metallogenic age, the Mesozoic and Cenozoic chromium deposits in China are mainly formed. In the metallurgical industry, chromite is mainly used to produce chromite alloys and metal chromium. Chromium iron alloy as the additive of steel production of a variety of high strength, corrosion resistance, wear resistance, high temperature resistance, oxidation resistance of special steel, such as stainless steel, acid steel, heat resistant steel, ball bearing steel, spring steel, tool steel and so on. Chromium metal is mainly used for smelting special alloys with cobalt, nickel, tungsten and other elements. These special steels and special alloys are indispensable materials for aviation, aerospace, automotive, shipbuilding, and defense industry production of guns, missiles, rockets, ships and so on. In refractory materials, chromite is used to make chrome bricks, chrome magnesia bricks and other special refractory materials. Chromite in the chemical industry is mainly used to produce sodium dichromate, and then to produce other chromium compounds, used in pigments, textiles, electroplating, tanning and other industries, but also to produce catalysts and catalytic agents. Chromite is a shortage of minerals in China, with small reserves and low production, and more than 80% of annual consumption depends on imports. Chromium has oxygen and iron affinity, so that the oxygen affinity is strong, and only in the case of high reduction and sulfur fugidity can show sulfur affinity. Chromium is generally trivalent under endogenetic conditions. The ionic radii of Cr3+, Al3+ and Fe3+ are close to each other, so there can be extensive isomorphism between them. In addition, the elements that can be replaced with chromium are Mn, Mg, Ni, Co, Zn, etc., so there is a wide distribution of chromium in magnesium ferric silicate minerals and accessory minerals. Under the condition of strong oxidation in the epigenic zone (alkaline medium), Cr3+ is oxidized to chromate ion in the form of Cr6+, and the inactive chromium ion becomes easily soluble chromium anion and migrates. In the case of highly polarized ions (such as Cu, Pb, etc.), the formation of insoluble chromium acid minerals. There are about 50 kinds of chrome-containing minerals found in nature, which belong to oxides, chromates and silicates respectively. In addition, there are a few hydroxides, iodate, nitride and sulfide. Chromium nitride and chromium sulfide minerals are found only in meteorites. Chromium minerals with industrial value belong to chromium spinel minerals, their chemical formula is (Mg,Fe2+)(Cr,Al,Fe3+)2O4 or (Mg,Fe2+)O(Cr,Al,Fe3+)2O3, its Cr2O3 content is 18% to 62%.

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