POTENTIAL ROLE OF FELDSPAR FELDSPATHOID MINERALS IN SECONDARY STEELMAKING/

The need for a fluorspar replacement in secondary steelmaking operatio ns has surfaced in recent years owing to accelerated environmental con cerns and dwindling reserves. In the present work, the behaviour of th ree candidate minerals, labradorite, potassium feldspar, and nepheline syenite, has been examined to determine their relative suitability as a fluxing agent to replace fluorspar in the CaO-MgO-SiO2 system. Both rheological and static slag-dolomitic refractory experiments were und ertaken; also, an investigation into the partitioning of silicon betwe en the modified slag and metal phases was conducted. All candidates sh owed similar rheological characteristics and increased refractory life when compared with fluorspar, with the potassium feldspar being the l east aggressive with respect to the refractory, Partitioning experimen ts in which nepheline syenite replaced fluorspar suggested some moveme nt of silicon from the slag to the metal phase; this may translate int o savings in silicon based alloy additions. (C) 1997 The Institute of Materials.