Physicochemical Problems of Mineral Processing, 36 (2002) 197-208 Fizykochemiczne Problemy Mineralurgii, 36 (2002) 197-208 Hidayet CEYLAN*, Cahit HİÇYILMAZ**,Taki GÜLER** COLLECTORLESS FLOTATION OF LEAD AND ZINC SULPHIDE FROM DEREKÖY ORE DEPOSITE Received March 5, 2002; reviewed and accepted May 15, 2002 A study on collectorless flotation of lead and zinc sulphide present in the Derekoy ore in the presence of sodium sulphide was performed. The parameters of the process and influence of sodium sulphide, zinc sulphide, conditioning time, pH and cleaning of concentrate were investigated. The results were compared with collector added flotation using several types of collectors. Kay words: flotation, galena , zinc sulphide, conditioning time, pH INTRODUCTION Sulphide minerals are readily amenable to flotation, but in most cases after a proper surface treatment. Thiol type collectors are most widely used to render selected constituents of a sulphide ore hydrophobic. However, at the Tsumeb concentrator in South Africa, galena and sphalerite are floated selectively from chalcopyrite without using any collector in the first 8 cells of each rougher bank (Boyce et al., 1970). Lepetic (1974) has also shown that chalcopyrite can be floated successfully by using frother alone after a dry autogenous grinding. These reports on collectorless flotation have rekindled an old controversy as to whether or not the sulphide minerals are naturally hydrophobic (Stewart and Finkelstein, 1973; Finkelstein et al., 1975; Fuerstenau, 1975; Heyes and Trahar, 1977; Gardner and Woods, 1979). Over the years, experimental evidences have suggested that hydrophobicity of sulphide minerals varies from none to that of sulfur. Gaudin (1932), Ravitz and Porter (1933), Fuerstenau (1975), Yoon (1981), Luttrell and Yoon (1984), Hayes and Ralston (1988), Matabishi et al. (2000) showed that collectorless flotation of sulphide minerals *Municipality of Çankaya, Ankara, Turkey **Middle East Technical University, Ankara, Turkey