Abstract:In order to solve the problem that it was difficult to separate valuable components from waste alloy cutters efficiently, a cleaning treatment technology of “two-stage leaching, fractional crystallization and physical separation” was proposed. In this paper, the effects of technological parameters on leaching behavior of valuable metals in iron and copper leaching processes were studied, and the physical separation of diamond was also studied. The results show that, under the conditions of H₂SO₄ concentration of 130 g/L, liquid-solid ratio of 12:1, stirring speed of 300 r/min, leaching temperature of 60 ℃ and leaching time of 36 h, the leaching efficiency of iron in waste alloy cutters is 97.6%, and more than 99% of copper and 100% of diamond enter into the iron leaching residue, realizing the selective separation of iron. Under the conditions of H₂SO₄ concentration of 250 g/L, oxidant HNO₃ concentration of 23 g/L, liquid-solid ratio of 10:1, stirring speed of 300 r/min, leaching temperature of 80 ℃ and leaching time of 26 h, the leaching efficiency of copper in iron leaching residue can reach more than 99.9%, while more than 94% of tin and all diamonds enter into the copper leaching residue, realizing the high-efficiency leaching of copper. The high efficiency recovery of diamond can be achieved by shaking table separation of copper leaching tailings. The industrial test not only verifies the correctness of the laboratory research results, but also shows that the wastewater generated in the wet process can be recycled, and no wastewater is discharged in the whole process.

Key words: waste alloy; leaching; resource recovery; copper recovery; diamond