Ferrochrome (FeCr) is an alloy of chromium and iron, generally containing 48 to 70% chromium by weight. It is produced in an electric arc furnace by the reduction of chromite ore. South Africa has the largest reserves of chromite ore and is also the world’s largest producer of Ferrochrome with most production being exported to China. The manufacture of steel is the largest consumer of ferrochrome, especially the production of stainless steel which container 10 – 20 % chromium. There is also significant demand in certain foundries where chrome alloys can contain as much as 27% chromium.
There are four main types of ferrochrome namely Charge Chrome, High Carbon Ferrochrome, Medium Carbon Ferrochrome and Low Carbon Ferrochrome.
Charge chrome is a category of HCFeCr developed primarily to utilize lower grades of chromite ores with a lower Cr/Fe ratio. As such these alloys typically contain lower levels of chromium (48-52%) compared to High Carbon Ferrochrome (52% and above). Due to the reduction kinetics the silicon levels are also typically higher in Charge chrome running at 4 – 6 %.
These alloys are commercially important to steel and stainless steel producers that utilize Argon oxygen decarburization (AOD) and similar technology in that it allows cost effective addition of chromium units while still being able to maintain low carbon levels. Almost all charge chrome produced is utilized in these sectors as this alloy is not suitable for use in most foundry alloys, primarily due to the higher Si levels.
High Carbon Ferrochrome
High carbon ferrochrome (HCFeCr) is mainly produced by reduction of chromite ores by carbon in Submerged Arc Furnaces (SAF). The produced alloys contain 50-75% Cr depending on ore composition, around 1-2 % Si and about 8-9%C typically. South Africa HCFeCr has a lower Cr content of 50-53 % compared to that produced in other parts of the world which have a 60+ % Cr content. This is due to the lower Cr:Fe ratio found in South African chromite ore.
Mineral-loy supplies an excellent quality HCFeCr which yields high chrome recovery in the melt and will provide a consistent Cr:C ratio. Each batch undergoes a stringent quality inspection which has made Mineral-Loy a supplier of choice for HCFeCr.
Medium Carbon Ferrochrome
Medium carbon ferrochrome (MCFeCr) is produced by further refining of charge chrome. The silicon in the product is reduced to below 1.5 %, and carbon is reduced to less than 2 % Max. The process takes place in a convertor where the liquid charge chrome is bottom blown by oxygen and steam to reduce the carbon content. The final product, an intermediate carbon ferrochrome, is produced in either a granulated or lumpy form. Mineral-loy supplies MCFeCr with a proven record of quality. It is available in bulk bags, bulk or any other bespoke packaging requirement. Specification and sizing can be found on the Mineral-Loy website or upon request.
Low Carbon Ferrochrome
The production of Low carbon ferrochrome combines charge chrome, quartzite and reductants in a SAF to produce ferro-silicon-chromium (FeSiCr) in a dry or slag-free process. The ferro-silicon-chrome contains low carbon content which is generally 0.1 % maximum.
The product analyses can be viewed here: https://www.mineral-loy.co.za/mineral-loy-product-list/ferro-chrome/