Poster (EARTH)

[PE1-029] Cementation of Co ion from zinc concentrate leach solution followed by magnetic separation for Co recovery

○Sanghyeon Choi¹, Kyoungkeun Yoo¹ (1. Korea Maritime and Ocean University)

Keywords:Magnetic separation, cementation, Ni magnetism, zinc powder

The Zn concentrate leachate contains impurity metals such as Cu, Sb, Co, Cd, Ni, which could affect the quality of zinc metal and the current efficiency of zinc electrowinning process. Therefore, the impurities metals are removed by cementation with zinc metal to precipitate impurities with less ionization tendency than zinc. After cementation, the filter cake in the form of an intermetallic compound is composed of unreacted Zn and reduced Ni, Cu, Co and Sb. Most of these residues remain stored because there is no proper recovery method and landfills are prohibited because heavy metals are contained. Because Ni has magnetism, when magnetic separation is performed, it was expected that impurities composed of intermetallic compounds are concentrated together with Ni in magnetic fraction. This study is aimed at developing recovery process of Co from cementation precipitate by using magnetic separation. The synthetic electrolyte was prepared by adjusting the concentrations of Ni, Co, Sb and Cu of sulfate in distilled water. As the initial concentration of nickel increased, the impurity metals such as Ni, Co, Cu, Sb were concentrated to the magnetic fraction, but the zinc also concentrated. The impurity metals were concentrated about 70~74% in the magnetic fraction, while zinc was about 44% under the following conditions: [Co]=[Sb]=[Cu]=150ppm, [Ni]=300ppm, Zn powder : 10g/300ml, N₂ introduction : 300cc/min, Temperature : 85°C, pH : 3.5~4.5, Magnetic intensity : 3000G. Thus, it’s possible to recover the impurity metals, which are valuable metals such as Ni, Sb and Co, are concentrated as magnetic fraction by Ni magnetism and to recover Zn as non-magnetic fraction by using magnetic separation.