Properties
Chromite FactsChromium is one of modern industry's most essential and versatile elements. In addition, it is one of the most important strategic and critical minerals. Of the many minerals that contain chromium, chromite is the only ore of commerce. It has a wide range of usage in three types of industries, namely the metallurgical, chemical and refractory. Chromium's use in iron, steel and nonferrous alloys enhances hardness and resistance to corrosion and oxidation. The use of chromium to produce stainless steels and nonferrous alloys are two of its more important applications. Other applications are in alloy steel, plating of metals, pigments, leather processing, catalysts, and refractories. Chromium is a steel-gray metal similar to platinum on luster. Some chemical constant of chromium include atomic number, 24; atomic weight, 51.996; density, 7.19 grams per cubic centimeter; melting point, 1,857 degrees Celsius (plus or minus 20 degree Celsius); and boiling point, 2,672 degrees Celsius. Chromium metal in its purest form (99.96% chromium) is produced in limited quantities by vapor deposition from anhydrous chromium iodide. Commercial chromium metal is produced either by electrolysis of a chromium-containing electrolyte or by aluminothermic reduction of pure chromic oxide. For most metallurgical applications, chromium is primarily used as additive in the form of alloys with iron and carbon as ferrochromium, or silicon as ferrochromium-silicon. Charge chromium is essentially a high-carbon ferrochromium with high silicon content. Chromium alloys, as well as chromium metal, are made in a number of commercial grades. The mineral chromite consists of varying percentages of chromium, iron aluminum, and magnesium oxides. Historically, chromite has been classified into general grades associated with end use: metallurgical, chemical and refractory. During the past decade, technological advances have allowed considerable interchangeability among the various grades, particularly chemical grade, which can be used in all three industries. Chromite ore and concentrates derived from chromite ore are further classified into three categories. These are ore and concentrate containing not more than 40% Cr2O3 (refractory industry), containing more than 40% Cr2O3 but less than 46% Cr2O3 (refractory, chemical and metallurgical industry), and 46% or more Cr2O3 (metallurgical and chemical industries). Of the World's total production of chromite; approximately 94% is smelted into ferrochromium alloys. These are for subsequent use in the stainless steel, steel and other alloy industries. While China is the leading consumer of chromite in the world accounting for 70% of the world's production; Japan remains by far the world's largest average annual producer of stainless steel, followed by the U.S., China, Korea, Germany, Italy, Taiwan and India. Chromium metal is produced by the aluminothermic or electrolytic process. It is mainly used for specialty alloys. Two percent of the world's production of chromite was used in 2007 for chromium chemicals. The primary product from the chromite is sodium chromate. From this, a variety of other chemical products are made and used, for example, for tanning leather, as coloured pigments in paints, plastics and ceramics, and metal finishing such as chromium plating. Production of chromite for refractory use and foundry sands is about 4% of world production of chromite. Refractory chromite is used in sectors of ferrous and non-ferrous metallurgy, in cement kilns and in the glass industry. The value of chromite varies on the grade; high grade chromite (>40% Cr2O3) is currently valued at approximately US$150 per tonne. South Africa and Zimbabwe hold approximately 90% of the world's chromite reserves and resources. Major producers include Assmang Ltd., Kermas Group Ltd., (formerly Samancor Chrome Mines, South Africa), Xstrata South Africa Proprietary Ltd., and International Ferro Metals Ltd. World production of chromite in 2007 was 22 million tonnes, with the most intensive mining occurring in the Bushveld Igneous Complex in South Africa, followed by Kazakhstan and India. Other important countries with chromite deposits include Brazil, Finland, Russia, Turkey and Zimbabwe. In 2008, South Africa was unable to provide enough inputs for its electricity production, directly impacting the energy-intensive mining and processing of chromite ore. Total South African supply was affected markedly, and although oil prices have come down as a consequence of the credit crisis, peak oil logic dictates oil prices will rise again in the near future and remain above current levels. Global outlook is for continued rising prices and increasing demand. A large supply of this strategic metal in Canada, one of the most stable mining jurisdictions in the world, would be of great significance to the United States, which is currently dependant on chromium imports. | |
