Abstract: A smelting slag from containing copper sludge (referred to as copper slag in the following) contains 3.50% copper， which mainly exists in the form of the metal copper and Cu-Ni-Sn alloy. The dissemination particle size of copper material is not uniform， of which the refractory particle size of -0.01mm accounts for about 55%.The flotation process of copper slag was studied， and the effects of grinding fineness，roughing pH and butyl xanthate dosage on flotation indexes were investigated. The open-circuit comparison tests between whole-grain flotation and sieving and flotation processes were also carried out.The results showed that under the condition of grinding fineness of 85.76% accounting for -0.075 mm with butyl xanthate as collector and terpenol oil as foaming agent， the copper concentrate with copper grade of 20.56% and copper recovery of 65.98% can be obtained by full-grain open-circuit flotation.The copper concentrate with copper grade of 15.65% and copper recovery of 56.52% and +0.15 mm product with copper grade of 22.56% and copper recovery of 18.63% were finally obtained by sieving and flotation. The comprehensive recovery of copper reached 75.15%， and the copper grade of tailings was reduced to 0.49%.The middles of the whole-grain closed circuit flotation are easy to accumulate， and the sieving and flotation closed circuit test process is stable. The final +0.15 mm product and flotation concentrate have a comprehensive copper recovery of 85.15% and a copper grade of 11.90%， which meet the smelting requirements of the furnace.

Key words: copper-bearing sludge, copper smelting slag, screening, flotation