The copper anode slime with high tellurium content (about 3%) is first roasted by sulfation at 250℃, then the selenium dioxide is volatilized at about 700℃, and the tellurium remains in the roasting slag. After leaching copper sulfate in the leaching slag with water and then leaching with NaOH solution, sodium tellurite can be dissolved and neutralized with sulfuric acid to form a crude tellurium oxide precipitate. After the sediment is purified, it is dissolved in the NaOH solution, and the concentration of tellurium in the solution is maintained at 100g/L. 160g/L of NaOH and then Electrowinning can prepare tellurium with a purity of 98%~99%.

tellurium leaching for electrowinning

electrowinning Cathode plate and anode plate for tellurium