Normally the basic oxygen process for steel-making, generates slags at a rate of 120 to 150 kg/ton of steel. The actual composition of BOF slags will vary significantly, depending upon a number of factors, e.g., the sulfur and phosphorus levels required in the final product. Some steelmaking slags can be recycled to the blast furnace for recovery of the iron units they contain and because of their beneficial fluxing properties. Chemical composition, and specifically the phosphorus content, is a critical consideration in establishing the amount of BOF slags which can be recycled. It is noted that Japanese blast furnace operators rely on the supply of relatively high phosphorus Australian ores, hence, the amount of recycled slag, in Japan, has to be maintained at a relatively low level. As a consequence, there is a continuous increase in the amount of BOF slag that has to be stored or dumped by the steel plant. From the foregoing comments, it is evident that there is a strong incentive to reduce steelmaking slag volume. The key toward this end is a more effective dephosphorization reaction.In steelmaking processes, fluorspar has played an important role. The chief function of fluorspar is to aid in promoting rapid lime solution in slag in basic oxygen furnace. Fluorspar is a slag fluidizer and lowers the fusion points of the slag. Due to recent environmental requirements and health considerations, however, application CaF_2 in steelmaking processes would be very much restricted in the near future. In this paper discussion will also be made on the effect CaF_2 on phosphorus removal.
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