Oxide impurities, especially alkaline earth oxide, are removed from ti-containing slags by mixing with alkali metal carbonates, sulfates, or chlorides, reacting the mixture with so3 or so2-o2 mixtures to form sulfates of the impurities, then leaching the sulfates with water. The slag is rendered more suitable for chlorination to obtain ticl4. Thus, a ti-enriched slag was blended with 10 pct na2so4 and 2 pct powdered sugar, pelletized, and heated to 700 deg c for 7 h in a flow of 300 so3 and 100 o2 cm3/min. The treated pellets were ground and leached with water for 3 h. Impurity removal was: fe 29.8, Mgo 84.6, Cao 78.9, and mno 84 g (ed. Note: probably should be pct). Chlorination of the leached slag at 1,050 deg c for 6.5 H recovered 94.5 pct of the ti.
U.S. Pat. 4,362,557, Dec. 7, 1982; Chem. Abstr. 96:166,303H