Co-production of steel and titanium: process engineering feasibility

Abstract

Continuous smelting of ilmenite is proposed, eliminating chlorine based technology except perhaps as a means for dealing with associated radioactivity. Concentrates are fed onto the first of three melt circulation loops, in which optionally both the oxidic melt and the liquid steel layers may be circulated. Molten iron formed joins the circulating bottom layer of liquid steel, which extracts impurities including chromium, silicon, manganese, vanadium, niobium, aluminium and phosphorus. Liquid steel is withdrawn for refining before continuous casting. The oxidic melt has its carbide content increased in the second of the melt circulation loops. Continuous vacuum refining is then conducted in the third loop operating at 1 mbar using vacuum steel degassing steam jet ejector systems, yielding a theoretical (TiO₂+ZrO₂) equivalent in the titanium oxycarbide melt of ‘four nines’ (99·99%) purity at 84% recovery. The refined melt feeds the electrochemical deoxygenation reactor described in the patent literature for continuous production of liquid titanium.