A series of laboratory batch flotation tests was conducted on a suite of calcium-ferrite-based slags made in continuous pilot plant smelting trials. The smelting tests were conducted as part of a wider CSIRO Minerals' research project aimed at developing a single-stage continuous copper making process. The slags treated included two moderately reduced low copper slags, an oxidised high copper slag and a very reduced low copper self-pulverising slag. The total copper content of the slags varied from 5.2 percent to 15.1 percent Cu. The copper was present in the form of metallic copper, oxide copper and copper ferrite phases with the dominant phase in all slags being metallic copper. The slags were crushed, ground, wet screened at 210 or 75 mu m to remove coarse metallic particles of copper, and floated at natural pH (about pH 11) using reagents and conditions appropriate for the selective recovery of the copper phases. In rougher-scavenger tests on the slags total copper recoveries between 80 percent and 87 percent were obtained for three of the slags tested. The best result for the fourth slag (low copper self-pulverising slag) was 74 percent copper recovery. Coarse copper metal was present in the flotation tails for this test suggesting the pre-flotation screen size was too coarse. Further optimisation of the grinding and flotation conditions for this slag should yield an improved copper recovery. Minor differences in copper/iron selectivity for the flotation tests on the four slags were observed with the low copper slag giving the most selective result and the high copper slag the least selective result. These trends were generally consistent with the kinetic data obtained in the flotation tests and the given copper mineralogy for the different slag types.
展开▼
