HYDROMETALLURGICAL METHODS FOR TREATING COPPER ELECTROLYTIC SLUDGE

摘要

A hydrometallurgical method developed in the Gintsvetmet Institute for treating anode sludge and based on sulfite leaching (pH 9.2 to 9.6) of gold or hydrochloric acid leaching in the presence of an oxidizing agent permits its efficient quantitative separation from silver at the head of the process, eliminating thereby the need for production of Dore metal and its further electrolytic refining. In the process of sludge treatment, gold and silver are separated into individual high-grade products, I.e., metal powders, and their refining is, therefore, significantly simplified and can be accomplished by the use of sodium sulfite as the main reagent playing the role of a complexing agent and reductant of gold, silver and selenium. Tellurium, lead and antimony are removed from the process circuit in the form of rich intermediate products. Elimination of roasting, sintering and smelting processes improves the environmental performance of the operations and reduces the operating cost for dust recovery and off gas treatment. Investigations conducted have demonstrated that sludge from the Balkhash smelter (Kazakhstan) and Kovoguty Krompahy smelter (Slovakia) can be successfully treated using the proposed technology with recoveries into corresponding metal powders of 99.57% and 95.45% of gold and 99.5% and 98.3% of silver, respectively.