processes coal using a method called calcining. Calcining is a process whereby anthracite coal is fed through a rotary kiln (at temperatures between 1,000 and 1,200 degrees centigrade) and devolatilisation takes place - sulphur content is lowered and gases such as nitrogen are burnt off. The final product is calcine, which is a coke substitute with a high carbon content. The final product is used as a reductant in the manufacturing of steel and manganese. Quantum has been profitably carrying on this business for the last eight years through its wholly owned subsidiary Southern Coal (Proprietary) Limited. Current customers of Southern Coal include some of the largest steel and manganese producing companies in the world, including BHP Billiton and Arcelor Mittal Steel. The company expects that it will be able to expand the current business of Southern Coal.
Updated 9 February 2012
Carbon Advancement Technologies
THE USE OF CARBONACEOUS MATERIALS IN STEELMAKING
In steelmaking processes,coal is used to supplement the energy input and to reduce iron oxides in the slag. Foamy slag practice is discussed, and the most widely used types of ladle recarburizers, their properties, and manufacture are described. It is concluded that the use of carbon sources, mainly for supplementing energy and as reductants, will increase in the future, but that demands on the purity of the materials will probably become more stringent. If hydrogen were manufactured at a competitive cost, it could become an alternative fuel and reductant in the field of iron and steelmaking.
Throughout the history of iron- and steelmaking, carbon has always played a dominant role as a fuel and a reducing agent. The volume of carbonaceous materials used in steelmaking today is still modest compared with the quantities consumed in ironmaking, but steelmakers are using coal on an increasing scale to supplement their energy requirements. Coal is also the energy source and reductant used in most of the direct steelmaking processes being developed at present. However, this will not significantly change the total consumption of carbon per tonne of crude steel produced, because the first step in most of the proposed concepts is the smelting reduction of iron ore with carbonaceous materials. At present, carbon is used in steelmaking processes as a supplementary source of energy, for the reduction of iron oxides in the slag, in foamy slag practice, and for the recarburization of liquid steel.
As the resources of crude oil and natural gas diminish, and the prices of natural gas and electricity increase, the use of carbonaceous materials in steelmaking can be expected to increase, provided the costs involved in the cleaning of the off-gas to meet increasingly stringent environmental specifications can be justified economically. Future steelmaking technologies will possibly include faster processing in smaller units. Improvements in the control of these processes will be essential, and this will result in more-stringent requirements regarding the quality of the raw materials used. Volatile and mineral matter, sulphur, phosphorus, and nitrogen may become unwanted compounds in rapid, precision-melting technology, and other sources of energy may have to be substituted for coal. Hydrogen is one of these, and there are a number of reasons, including the prevention of environmental pollution, that favour the use of this clean energy source when hydrogen prices are becoming competitive. High-quality carbon is another substitute, and clean chars, or products derived from coal tars, may become sought-after materials in future steelmaking technologies.
Most carbonaceous materials used in today's steelmaking processes serve to supplement the energy input into melting furnaces, either to lower the consumption of other types of energy or to increase the melting rate. In electricarc furnaces, carbon sources are used additionally for the foamy slag practice or to lower the iron oxide in the slag, especially when low-carbon directly reduced iron is melted. For most of these applications, coal with a low content of volatile matter and sulphur is preferred. In future technologies, such as direct steelmaking from iron ore, carbonaceous materials will be the main source of energy for heating and as reductants for the ores.