Abstract: Alkaline separation agents are added into high titania bearing blast furnace slag. Structure of perovskite in the slag is destroyed at the high temperature and co-molten slag formed is leached in water. The tests indicate that the interaction of slag and separation agents belongs in the acid一base reaction at optimum temperature ranges of 1 200~1 300℃ and TiO₂ content in the slag is reduced to a certain degree after leaching.