Flotation separation of chalcopyrite using acacia gum as a novel fine quartz depressant

Recently, global carbon neutrality policies driven by climate change have heightened the demand for environmentally sustainable processes across various industries. This trend extends to the field of mineral processing, where the exploration of eco-friendly reagents, particularly for flotation processes, has emerged as a critical research focus. In this context, the present study aims to investigate, both experimentally and theoretically, the feasibility of using acacia gum (AG) as a depressant during the beneficiation of chalcopyrite from a synthetic siliceous low-grade copper ore. A higher AG adsorption onto chalcopyrite relative to quartz containing Zn (quartz-Zn) was noticed to decrease with increase in pH. Further, theoretical studies performed indicated that the complexation energies for chalcopyrite-AG and quartz-Zn-AG complexes were-346 kJ/mol and-272.6 kJ/mol and this is in tandem with the adsorption results. Additionally, the mineral-AG complexation resulted from partial covalent, conventional hydrogen bonding and other non-covalent interactions. Flotation studies conducted on chalcopyrite-quartz mixture with the weight ratio of 1:24 mimicking Mpanda Mineral Field siliceous ore, at pH 8.5 yielded Cu grade, recovery, separation efficiency and enrichment ratio of 24.7 %, 93.3 %, 92.3 % and 24.0, respectively, in presence of Zn, AG, potassium amyl xanthate, methyl isobutyl carbinol of 80 g/t, 200 g/t, 60 g/t and 25 g/t. The adsorption of AG onto activated quartz attests that the polysaccharide is a potential depressant for quartz in presence of Zn in siliceous ores.