When producing high grade mattes in smelter plants, copper losses in the slag are inevitable. Hence, the recovery of copper from slag has been the focus of many research projects, copper flotation being a widely used process. In the Khatoonabad converter, 200 t/d of slag are presently produced with a grade of 2.3 percent Cu. Assuming a 85 percent recovery by flotation, about 3.9 t/d copper could be produced, which is of prime importance economically. In the present work, a sample of this slag was crushed and ground in the laboratory to liberate the copper-bearing minerals. Following mineralogical studies, optimum laboratory flotation parameters were obtained, resulting in 90.27 percent recovery and 9.42 percent of copper grade for the rougher stage. At pilot scale, a pulp of 28 percent solids was floated at ph 10.5 using 40 g/t of Z6, 25 g/t of R407 and 20 g/t of MIBC and A65. A recovery of 83.52 percent was obtained for a concentrate grade of 28.36 percent Cu. In the rougher cells, the feed consisted of particles 94 percent finer than 74 microns whereas in the cleaning stage, particles were 95 percent finer than 44 microns. Based on the obtained results, the Sarcheshmeh Khatoonabad converter slag is presently being fed to the Chargonbad flotation plant, where a concentrate of 32 percent copper at 86 percent recovery is being produced.
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