A corona-electrostatic technology for zinc and brass recovery from the coarse fraction of the recycling process of spent alkaline and zinc–carbon batteries
2021
Calin, Laur | Catinean, Andrei | Bilici, Mihai | Samuila, Adrian
The recycling of spent alkaline and zinc-carbon batteries aims to minimize the waste, to avoid environmental pollution, and to provide valuable secondary raw materials. The paper presents the development of a new technology, based on corona-electrostatic separation, for the recovery of zinc and brass granules from the coarse fraction obtained in the recycling process of alkaline and zinc-carbon batteries. A free-fall electrostatic separator was equipped with an extended needle-type corona electrode, to strongly charge by ion bombardment all the components of the granular mixture. The difference in density between metallic granules (zinc and brass) and other non-metallic components leads to different trajectories and makes possible their collection as separated fractions. The recovery rate and purity of the metallic fraction - as high as 99% and 92% respectively, was obtained with a 52% recovery rate the non-metallic fraction. A new electrode configuration was employed to improve the granule collection efficiency, leading to a significant increase in both the recovery rate of non-metallic fraction, and the purity of the metallic fraction - 97.6% and 99.2% respectively. The experimental results show that the proposed corona-electrostatic technology allows the recovery of about 390 kg of zinc and brass with over 99% purity from 1,000 kg of granular mixture, with an energy consumption of about 48 kWh. The corona-electrostatic technology represents a competitive alternative for the recovery of zinc and brass granules from spent alkaline and zinc-carbon batteries.
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