Flotation separation of chalcopyrite from talc using a new depressant carrageenan

As a typical gangue mineral in many sulfide deposits, naturally hydrophobic talc needs to be depressed by adding depressants to achieve a good flotation separation. Conventional talc depressants lack selectivity, resulting in the depression of both talc and sulfide minerals. In this study, carrageenan was applied as a selective depressant for talc. The mechanism of carrageenan in the flotation separation of chalcopyrite from talc when using collector sodium butyl xanthate (SBX) was investigated. Micro-flotation results showed that carrageenan can efficiently and selectively depress talc and barely influenced the flotation of chalcopyrite. The artificial mixed minerals flotation results further confirmed that carrageenan was a selective depressant for talc. A concentrate with Cu grade of 32.42 % was obtained at 91.86 % recovery from their artificial mixtures of minerals. The flotation results indicated that carrageenan exhibited stronger depressing ability than the conventional talc depressants of CMC and guar gum, suggesting it could become a promising potential depressant in the selective flotation separation of chalcopyrite from talc. Adsorption mechanism of carrageenan on the surface of talc was investigated using zeta potential measurements, adsorption measurements, FTIR measurements, XPS measurements and Langmuir adsorption model. The zeta potential measurements and adsorption measurements indicated that carrageenan selectively adsorbed on talc surface and therefore changed the zeta potentials. The FTIR results and XPS tests illustrated that the adsorption of carrageenan on talc occurred through physical interactions rather than chemical complexation. Langmuir adsorption modeling confirmed the major role of hydrophobic interaction.