Noble ferroalloys

Noble ferroalloys Ferroalloys are a group of materials which are alloys of iron that contain a high percentage of one or more non ferrous metals as alloying elements. These alloys are used for the addition of these other elements into liquid metal. They are normally used as addition agents. More than 85 % of ferroalloys produced are used primarily in the manufacture of steel. Ferroalloys are usually classified into two main categories namely (i) bulk ferroalloys and (ii) noble or special ferroalloys. Noble ferroalloys are of high value and consumed in low proportions. These ferroalloys are one of the vital inputs required for the production of special types of steels and are used as additive inputs especially in the production of alloy and special steels. Noble ferroalloys (Fig 1) are ferro nickel (Fe-Ni), ferro molybdenum (Fe-Mo), ferro vanadium (Fe-V), ferro  tungsten (Fe-W), ferro niobium (Fe-Nb), ferro titanium (Fe-Ti), ferro aluminum (Fe-Al), ferro boron (Fe-B). There are some noble ferroalloys which are having more than one non ferrous metal as alloying elements. Examples are ferro silico magnesium (Fe-Si-Mg), ferro silico zirconium (Fe-Si-Zr), ferro nickel magnesium (Fe-Ni-Mg) etc. Fig 1 Noble Ferroalloys Ferro nickel Fe-Ni is used for alloying in the production of stainless and construction steels. Laterite ore is the main raw material for the production of Fe-Ni. Laterite ore is characterized by a relatively low nickel content and a high moisture content together with chemically bound water in the form of hydroxide. Typical laterite ore contains 1 % to 3 % Ni and a moisture content of 5 % to 10 %. Besides laterite ore, coke and/or coal is needed as a reducing agent, since Fe-Ni production takes place by a carbothermic process. Fe-Ni can also be produced from secondary raw materials, such as...