In this study, iron selectivity behaviour of copper smelter slag (CSS) flotation tailings (38.08% Fe, 0.35% Cu, 4.48% Zn, 0.16% Co, 0.37% S) having fayalite and magnetite as major minerals was investigated with hematitization baking and base metals leaching methods using mineralogical and chemical analyses. For selectivity of iron, it was baked at temperatures of 650-690-700-710-730°C. The aim of the baking is to transform the almost all of the iron in the fayalite into the oxidized (non-soluble) form and the base metals into the sulphated (soluble) form. The temperature that had the lowest hematitization rate of iron was found to be 650°C, and the highest temperature was found to be 730°C. To examine the dissolution behaviour of baked CSS flotation tailing was leached at 50°C at a 1/10 (w/v) for 1 hour by using water. After baking at 690°C calcine and leaching residue, S values were determinated to be approximately 17% and 9%, respectively. Baking made at 7000C, amount of sulfate also decreased to 10% and S content was measured as 4% of its leaching residue. As a result of this study, 6900C/7000C was determined as optimum conditions of hematitization baking and base metals were extracted selectively when the iron was remained at leaching residue in Fe2O3 phase. It was determined that, hematitization is high and the sulphates of the base metals are preserved at 7000C temperature. The fayalite phase completely decomposed into Si-O/Fe-O/Zn-S-O/Co-S-O compounds at 7000C baking which was the highest iron selective and base metals dissolute temperature.