Vahid Vahid Fard; Keivan Shayesteh; Pourya Abbasi; Saeid Salimi
Abstract
One of the effective and important steps of the production of Zn in zinc factories is the purification step to remove the general impurities such as cobalt, nickel, and cadmium that can cause the creation of problems in the electrowinning process. In Iran's zinc factories, firstly, at the hot purification ...
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One of the effective and important steps of the production of Zn in zinc factories is the purification step to remove the general impurities such as cobalt, nickel, and cadmium that can cause the creation of problems in the electrowinning process. In Iran's zinc factories, firstly, at the hot purification step cobalt using the manganometry method, and then at the cold purification step nickel & cadmium using the cementation method with the help of Zn powder removed. In the aim of this study is evaluated the usability of the cementation method instead of the manganometry method. In this paper, important and effective parameters such as temperature, Zn powder dosage, mixing time, amount of trioxide antimony, copper sulfate effect, particle size, zinc ions concentration, mixing speed, and pH of zinc sulfate solution were studied and optimized. The Optimal state is obtained at 85 °C, pH= 4.5, 20 mg/L Sb2O3 concentration, 8 g/L zinc dust, 600 rpm mixing speed in 75 minutes. Decreasing the particle size of zinc dust increased the removal efficiency, but increasing the amounts of copper sulfate and zinc ions caused decreasing in efficiency. Results showed that cobalt, nickel, and cadmium removal efficiencies for the manganomery method were 99%, 0%, and 20% and for the cementation method were 99.5%, 99.7%, and 99.9%, respectively. Also, results indicated that the cementation method due to the increase of soluble zinc concentration; not being removes of manganese ions; simultaneous removal of impurities such as cobalt, nickel, and cadmium in a single step; and saving time and cost, has a higher performance rather than to manganometry method.
