The role of zinc and sulfuric acid concentrations on zinc electrowinning from industrial sulfate based electrolyte

The effects of varying simultaneously the zinc/acid concentrations at a fix ed total sulfate, on the current efficiency, energy requirements, and depos it physical characteristics for the zinc electrowinning, using Kidd Creek z inc electrolyte, were investigated. The electrowinning experiments were con ducted using a laboratory scale apparatus, at plating cycles of 24 and 30 h , a current density of 500 A m(-2) and a temperature of 38 degreesC. These conditions are typical of those applied at the Kidd Creek zinc tankhouse. T he reagents presently used at Kidd Creek, namely strontium carbonate, Sapon in, Dowfroth 250, antimony and sodium silicate, were also continuously adde d to the cell electrolyte at levels similar to Kidd Creek practice. Scannin g electron microscopy and X-ray diffraction techniques were used to charact erize the deposits with respect to morphology and preferred orientation, re spectively. Cyclic voltammetry was used to study the effect of the zinc/aci d concentrations on the polarization behaviour of the electrolyte. In addit ion, the electrical conductivity of the Kidd Creek zinc electrolyte was mea sured and compared with other industrial sulfate-based zinc electrolytes.