Selective separation of hematite from quartz with sodium oleate collector and calcium lignosulphonate depressant

Iron ions activation of quartz is a tricky issue for efficiently sorting of target minerals in ferrous minerals flotation . The selection of an effective depressant is one of the most significant approaches to addressing this problem. In this study, the effects of calcium lignosulphonate (CLS), a widely studied novel depressant, on the flotation of Fe 3+ -activated quartz were investigated. The potential depression role of CLS in separating hematite from Fe 3+ -activated quartz in a sodium oleate (NaOl) flotation system was further explored. The flotation results indicated that the separation of hematite from quartz could be achieved by the selective depression of quartz in the presence of CLS. The results of zeta potential and spectroscopy analysis showed that CLS could absorb onto the surfaces of both hematite and Fe 3+ -activated quartz. The presence of CLS hindered the further adsorption of NaOl on quartz, whereas the NaOl adsorption onto hematite surfaces was limitedly affected. Compared with hematite, CLS might be more prone to react with the Fe sites on the surface of Fe 3+ -activated quartz, resulting in a relatively high final adsorption density on quartz surfaces, which was confirmed by X-ray photoelectron spectroscopy analysis and adsorption tests.