When Cu converter slag is used as a raw material for iron smelting, Zn in the slag must be removed inorder to avoid the trouble in the blast furnace operation. In the slag, Zn is found as various compounds i. e. ZnO, ZnO·Fe203, ZnO·ESiO2etc.In the present experiment, CaCl2·2H2O was selected as a chloridizing reagent, and the various conditions of chloride volatilization had been investigated by using zinc ferrite and ZnO-SiO2system. The results obtained can be summarized as follows.(1) In the case of excess addition of CaCl2·2H2O (above 44.75%), the conditions of zinc ferrite formation had no effect on removal of zinc, which amounted to 99%. However, in the case of less addition (below 30%), zinc ferrite formed at low temperature was more decomposable than that formed at high temperature.(2) The coefficient of decomposition of CaCl2·2H2O was about 50% in dry air. The form of zinc volatilized by roasting with CaCl2·2H2O was zinc chloride. This was determined by chemical analysis of the condensed material at about 400·C.(3) The addition of various metal oxides such as Fe2O3, TiO2, PbO and CaO showed the increased rate of removal of zinc, on the other hand, the addition of Al2O3, Na2O and MgO showed the reverse effect.(4) Under the conditions of this experiment, optimum roasting temperature and time were 1, 000-1, 100·C and 60 minutes respectively.