Ferroalloys

A wide range of ferroalloys is produced, reflecting not only the appropriate metallurgical application but also the composition of the ore in terms of its Cr2O3 content and its Cr:Fe ratio. The main alloys are high-carbon ferrochromium (HCFeCr), produced from ores with Cr:Fe ratios of 2.0-3.6, and having a chromium content of more than 60% and carbon of 4-6%, and charge chrome produced from lower grade ores, mainly from South Africa, with Cr:Fe in the range 1.3-2.0, and containing 50-55% Cr and 6-8%C. These two alloys are sometimes collectively referred to as high-carbon ferrochromium.

Some 6.3 million tonnes of HCFeCr were produced in 2006. South Africa accounted for 44% of production followed by Kazakhstan: 15%, China: 13% and India: 10%. Finland, Russia and Zimbabwe together contributed a further 12% whilst some 6 smaller producer countries brought the balance of 6%.

World High Carbon Ferrochromium Production in 2006

*Albania, Brazil, Iran, Japan, Sweden & Turkey

Maximum levels of the impurities sulphur, phosphorous and titanium are specified in the alloys and minimum or maximum levels of silicon, depending upon the steelmaking process which might require the exothermic oxidation of the silicon to provide additional energy.

Smaller quantities of chromium are added to the steels in the form of medium-carbon ferrochromium (MCFeCr) and low-carbon ferrochromium (LCFeCr) in stages or processes which require lower carbon levels. MCFeCr contains less than 5%C and LCFeCr has less than 0.1%C and less than 1% Si. LCFeCr is generally used by steelmakers for their final trimming adjustments to the steel composition.

There were 659,000 tonnes of Other Ferrochromium (MCFeCr and LCFeCr) produced in 2006 with China, Russia, South Africa and Kazakhstan being the main producers.

World Other Ferrochromium Production in 2006

*Brazil, Germany, Japan & Turkey

Ferrosilicochromium (FeSiCr) is also produced. It is used in the intermediate stages of LCFeCr production, through exothermic oxidation of the silicon with a chromite melt, or directly by some steel producers to add both Cr and Si to the melt rather than as separate alloys.