Recovery of zinc from high fluorine bearing zinc oxide ore

An ever increasing demand for zinc has resulted in worldwide efforts to exploit complex and lean grade reserves of zinc oxide ore. In the present study, experiments were conducted on zinc recovery from high fluorine bearing zinc oxide ore. First, the effect of different variables on fluorine removal was investigated. Optimum experimental conditions occurred when the temperature was 1173 K, roasting time was 90 min and air flow was at a velocity of 6 m min⁻¹; the fluorine removal from the samples reached over 93%. The results obtained indicate that fluorine removal is not enhanced by adding diluted sulphuric acid or water as a binder. Second, the roasted materials were leached with a diluted sulphuric acid, and then neutralised, flocculated and finally filtrated. The residual fluorine content in the leached solutions was <38 mg L⁻¹, which satisfies the requirement of fluorine content in the leached solutions for the production of electrolytic zinc.