concentrate will be lowered. Meanwhile, this method often brings difficulties of activating highly depressed pyrite, environmental pollution and high depression of noble metal such as Au, Ag and Mo. What is more, the float ability of chalcopyrite will be decreased because of the formation of hydrogen bond. Consequently, it has aroused wide concern that there search of reagents can realize coppersulfur separation atacidic and neutral pH,and a series of novel reagents were prepared, some of which appeared good performance in laboratorial and industrial practice.Some researchers found an effective method to separate pyrite from chalcopyrite. In their research, BKY-1 was used as depressant in a wide range of pH. The following researches showed that the difference in interaction energy contributes to the selective depression. So xanthate could be used as the collector to float chalcopyrite selectively. Peng used a specially designed mill, which could control the pH throughout the grinding processing to investigate the influence of grinding conditions on the flotation of chalcopyrite and copper sulfur separation. It turned out that iron oxidation species from grinding media played a key role in depressing the float ability of chalcopyrite. The float ability of pyrite was significantly improved after grinding with mild steel medium. 30 wt% chromium medium will increase chalcopyrite float ability as well as decrease the pyrite float ability to strengthen the copper–sulfur separation effects. Martin demonstrated that nitrogen conditioning could enhance thefloatability of pyrite because of galvanic interaction. But this effect could be reversed by raising the pulp pH or introducing air. This phenomenon could be used to separate pyrite from some other sulfide ores with air. The depressing ability of small polymers with various substituted functional groups such as carboxyl, sulfonate, hydroxyl and thiourea was researched. The results showed that hydroxy had the best depressing ability for pyrite depression and carboxyl had the best mineral selectivity. Their depressing ability in pyrite was strong because of the reaction with ferric ions/hydroxides,but they had no or little depression ability for sphalerite and copper activated sphalerite. Mitchell proposed that hetero coagulation with different minerals was an effective way to selectively separate minerals involved. They discovered that pyrite had a positive zeta potential () up to its iso electric point (IEP) at pH about 2.2, while chalcopyrite has a positive up to its IEP at pH about 5.5 and the hetero coagulation of chalcopyrite with pyrite will happen between pH 2.2 and pH 5.5; thus it, is impossible to separate these two minerals.Flotation tests showed that at pH = 10 thionocarbamate had good selective flotation of chalcopyrite from pyrite. It was revealed that pulp oxidation potential (Eh) and zinc sulfateplayed an important role in copper-activated pyrite recovery.At pH 9.0 the maximal recovery of chalcopyrite and pyriterealized when the Eh was 275 and 135 mV, respectively. The maximal separation effect achieved at 275 mV and the addition of zinc sulfate could increase the mineral separation by selectively depressing pyrite flotation because large amount offerric hydroxide groups formed on the pyrite surface, while ata lower Eh, such as 38 mV, the addition of zinc sulfate would improve flotation adversely because of the large increase of Eh. So zinc sulfate is not an effective mineral depressant at lower Eh values. Chen investigated the combination of sodium