Ammonia leaching of slag from direct-to-blister copper smelting technology

Abstract

Smelting of copper concentrates in a flash furnace directly into a copper blister results in the production of slag with high copper and lead content. The recovery of these metals is carried out in an electric furnace, from which copper–lead–iron metallic alloy is then processed in a converter furnace. In the presented work, copper and lead extraction studies were carried out by hydrometallurgical route under leaching in ammonium acetate solutions. The obtained results indicate the possibility of receiving quite high copper leaching efficiency from slag with a relatively low yield for lead extraction. The use of ammonium acetate solutions with a concentration of 5 mol/dm3 leads to leaching from the slag over 80% of the copper contained in it after 90 min of the process carried out at a temperature of 70 ℃. Model calculations related to the study of the kinetics of the process indicate that after 120 min of leaching it can be expected that 90% of the copper contained in the slag could be carried out into the solution.

Keywords

• ammonia leaching
• direct-to-blister copper flash smelting
• copper recovery
• leaching kinetics