Use of triboelectric techniques for separating talc from carbonate ore

The paper focuses on the possibility of applying electric separation techniques, based on the triboelectric charge and using a free-fall chamber, for separating the talc from carbonate ore. The electric separation chamber consists of a plexiglass structure and a pair of counterposed venetian blind electrodes, each connected to a voltage generator and supplied with –25 and +25 kV respectively. Tests were conducted on binary mixtures of talc/carbonate in the –0.3+0.053 mm size class, while varying temperature, talc/carbonate feed rate and charge intensity. The talc grains tend to be negatively charged and as a result are deflected towards the positive electrode while the carbonates grains are positively charged and are deflected towards the negative electrode. The findings highlight the importance of preheating the material and of interparticle contact phenomena. The experiments have shown that it is possible to obtain satisfactory results in the separation of talc from carbonate ore preheating the feed material to temperatures over 120 °C, while using a rotating tube as a feeder of the electric separator to promote interparticle contact.