Abstract:
Trepca Company, as per design capacity, can produce about 90,000 t/year zinc sulfate solutions as a by-product of neutral leaching of zinc calcine. Besides zinc, these sulfate solutions contain impurities such as Cu, Cd, Co, Ni, As, Ge, Sb, Se, Te and Ag with the following average concentrations: Cu and Cd = 0.2-1.2 mg/l; Co=1.0-10mg/l; Ni =20-50 mg/l; As, Ge, Sb, Se, Te and Ag = 0.1-0.5 mg/l. Based on the above data, it is evident that the selective recovery of these metals from these solutions represent a significant economic added value. In this point of view, in order to revive and improve operation practices as per design capacity in the Trepca Company, a project is undertaken in cooperation with FLOGEN Technologies Inc. in order to increase efficiency of the process through proper control and optimization. In this paper the existing refining process within the entire flowsheet is described as per design parameters. The recovery of metals by separation and cementation in metallic forms is overviewed based on the fact that these metals have higher electro-chemical potentials than zinc. The operation factors that have the most profound effect on the process such as impurity concentration, temperature, time, etc. are described. The improvement aspects of this process through proper control and automation will be subject of a subsequent paper in the future.
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