Selection of reductants for extracting selenium and tellurium from degoldized solution of copper anode slimes

This paper focused on investigating high-efficient reductants of recovering selenium and tellurium from degoldizedsolution of copper anode slimes.Firstly,the effect of various reductants on recovery rates of Se and Te was investigated based onthermodynamic analysis of various metallic ions in degoldized solution.Secondly,the single factor experiments were made toinvestigate the effect of the process parameters on recovering Se and Te with hydrazine hydrate.Finally,the hydroxylaminehydrochloride was added to intensify the extraction efficiencies of Se and Te.The results indicated that hydrazine hydrate was themost suitable reductant,and the recovery rates of Se and Te are71.23%and76.50%,respectively;the recovery rates of Se and Tewere92.07%and97.81%,respectively,under the optimal process conditions of hydrazine hydrate dosage of0.2133mol/L,H+concentration of4.305mol/L,reaction temperature of85°C and reaction time of5h;the recovery rate of Se was97.59%,and that Tereached up to100%when hydroxylamine hydrochloride dosage was1.5116mol/L.

Deselenization and detellurization of precious-metal ore concentrates by swelling oxidizing roasting and successive alkaline leaching

A new technique of swelling oxidizing roasting and alkaline leaching was proposed for deselenization and detellurization of pre- cious-metal ore concentrates. Alkali-metal and alkaline-earth-metal chlorides and carbonates were preliminarily selected as swelling agents. The roasting removal rate and alkaline leaching rate of selenium and tellurium were investigated, and NaCl was selected as an appropriate swelling agent. Furthermore, the effects of various factors on the selenium gasification rate and leaching rate of selenium and tellurium were investigated. The results show that the selenium gasification rate reaches 88.41% after swelling oxidizing roasting for 2 h at 510~C using an NaC1 dosage coefficient of 100 and a sulfuric acid dosage coefficient of 1.3; the amorphous elemental tellurium is completely transformed into TeO2. The roasted product is subjected to alkaline leaching using a 100 g/L NaOH solution, which results in a selenium leaching rate of 10.51%, a total selenium removal rate of 98.92%, and a tellurium leaching rate of 97.64%. In the alkaline leaching residue, the contents of selenium, tellurium, gold, platinum, and palladium are 0.7825%, 5.492%, 8.333%, 0.2587%, and 1.113%, respectively; the precious metals are enriched approximately sixfold.