Chromium ore, or chromite, is found only in dense rocks formed by the solidification of lava.
Chromite deposits are found on the immediate surface of the Earth as well as deep underground, so both open-pit and underground mining methods can be used to extract them.
Chromite is an abundant world resource which, according to the United States Geological Survey, exceeds 11 billion tons and will be adequate to satisfy world demand for hundreds of years to come.
Since the year 2000, chrome ore production has been steadily on the rise, increasing from 15 million tons to 25 million tons in 2008. This impressive increase can be explained by the swift rise of stainless steel demand in the modern world, as well as by intensified local chromium alloys production that has been happening in recent years in China.
The majority of the world`s chromite, 95%, is utilized as ferrochromium alloys within the metallurgical industry.
Chromite is subjected to a high temperature reduction process, referred to as smelting, in order to produce alloys essentially made up of iron and chromium with small amounts of carbon and silicon.
The amounts of carbon and silicon in a particular alloy vary according to the grade or type of alloy, as well as what sort of impurities are present, such as sulfur, phosphorous and titanium.
Uses and Applications
Chromium is a multifaceted element that can be used in a diversity of ways in the steel and alloy, chemical and refractory industries.
95% of the world`s chromite production is smelted into ferrochromium alloys and used in the stainless steel, steel, and other alloy industries.
In 2008, 2% of the world`s chromite production was utilized in the production of chromium chemicals, which are primarily used to create sodium chromate.
Chromite is also used for refractory purposes and foundry sands. Refractory chromite is used in the metallurgy, cement, and glass industries to line kilns, furnaces, and reactors that require a lining that can withstand high temperature levels.
A small percentage of chromium is used to create chromium metal, a nearly 100% chromium product generally used for specialty alloys.
Finally, high resistance to corrosion and extreme strength make Chromium an optimum substance regularly used for plating and metal finishing.
Ferrochrome and Stainless Steel
Ferrochrome (FeCr) is an alloy made up of 50%-70% chromium and 30-50% iron. The alloy is a product of electric arc melting of iron magnesium chromium oxide, chromite, and chromium ore.
Within the steel industry, the production of stainless steel uses over 80% of the world`s ferrochrome, making it the largest consumer of the alloy.
On average, there is an 18% chrome content in stainless steel, which provides its characteristic appearance and resistance to corrosion.
HC ferrochrome created from high grade ore is more frequently utilized for specialist applications in which high Cr to Fe ratios are important and other elements involved are best kept at minimum levels.