REDUCTION OF FLUORSPAR CONSUMPTION IN SECONDARY STEELMAKING

One of the most difficult problems facing the steelmaking industry tod ay is how to reduce costs while concurrently providing a more environm entally sound process. An area where this may be addressed is the sele ction of raw materials for synthetic slags. Using mineral substitution s for traditional slagmaking components may help alleviate these conce rns; however, at the same time it is essential that the final slag mai ntains an appropriate physical and chemical character and that the fin al steel product does not suffer from the change. In particular, this study presents a series of laboratory and industrial tests whereby flu orspar, in a steelmaking slag, was partially or fully replaced with a feldspathoid mineral. Results obtained from the laboratory investigati on showed that the modified synthetic slags were rheologically accepta ble and were not unduly aggressive with respect to refractory consumpt ion. The plant scale trials were successful with regard to sulphur and hydrogen levels and cleanliness of the final product, and presented n o process problems such as slag foaming or tundish clogging. The resul ts, both experimental and plant scale, are presented and discussed wit h reference to possible cost savings related to both slag additions an d ferroalloy consumption.