Studies on extraction of selenium and tellurium from copper electrolytic slimes by sublimation in vacuum

Abstract

Anode slimes obtained from the electrolytic refining of copper contain selenium and tellurium in the form of selenides and tellurides of metals, e.g., copper and silver. The slimes were treated with sulfur under vacuum; selenides and tellurides decomposed to give selenium and tellurium in metallic form which condensed on a cooler zone. Various parameters studied were temperature, time, sulfur addition, briquetting pressure, and fineness of sulfur added. The X-ray diffraction studies carried out on treated and then on untreated slime proved the reaction of sulfur with selenide and telluride of copper to give copper sulfide, selenium, and tellurium. Sulfurization at around 475°C for 60 min gives optimum recoveries.