EAF-FOAMY SLAG IN STAINLESS STEEL PRODUCTION NEW EXTREMELY EFFICIENT TECHNOLOGY EASY TO HANDLE AND COST-EFFICIENT

摘要

Economy of the electric arc furnace technology is strongly dependent on the efficiency of electrical energy introduced into the metal bath. Slag foaming practice for carbon steel grades has since long time its daily application but for stainless steels not successfully yet. Production cost lowering is achieved by improved thermal efficiency and operation conditions by stabilizing of the arc activity. In consequence of such technology the refractory and electrode consumption as well as noise level is perceptible decreased. All these effects can be now achieved at the stainless steel production thanks a new patented technology of SMS Demag AG / Germany developed in common work with the AGH-University of Science and Technology in Krakow /Poland and tested industrially by Acesita S.A./ Brazil. The new technology distinguishes fundamentally in comparison with all known applied and trialled technologies working on the basis of injection procedure. The special prepared briquettes are used as reacting agent on the slag and metal phase boundary forming carbon monoxide and dioxide necessary for the foaming effect. This idea was first tested in laboratory at EAF conditions. Suitable viscosity of the slag was tested according to the normal production conditions.Controlled high foaming level covering completly the electric arc allows application highest transformer taps resulting in longer electric arcs and high temperature gradient in the range of 13-14 K/min.