China Nonferrous Metallurgy

The 40t (wet weight) mixed residue stockpiled in the rare & precious metals plant of Daye Non-ferrous Metals Smelter contains Te of appr. 7t and a small amount of base metals, as well as a thimbleful of precious metals. To achieve the goal of industrial treatment, an exploratory test has been carried out by drawing on the process route of recovering Te from the solution resulting from gold precipitation, and the following conclusions have been obtained. By adopting the process flow of HCl-chlorination with sodium chlorate-neutralizing hydrolysis, the leaching rate of Te in the mixed residue can reach above 99%, the precipitation rate can be over 77% and the Te yield rate surpasses 77%; by adopting the process flow of solution resulting from gold precipitation-chlorination with sodium chlorate-neutralizing hydrolysis-zinc-dust cementation, the leaching rate of Te can reach above 94%, the precipitation rate above 75% and the yield rate of Te above 71%. The comparison shows that the latter process flow is more applicable for actual production. It has been verified by industrial test that the Pt-Pd concentrate obtained from treating the mixed residue by the process flow of solution resulting from gold precipitation-chlorination with sodium chlorate-Pt-Pd precipitation contains Te of more than 29%, 40t Te can be recovered, and a profit of appr. 1.6564 million CNY can be realized.