Examination of the flash smelting slag decoppering proces kinetics

Piotr Madej, Józef Czernecki, Tomasz Sak, Grzegorz Krawiec, Bogusław Onderka, Łukasz Kortyka, Katarzyna Klejnowska, Piotr Palimąka

In 1978 Copper Smelter Głogów II started using the flash smelting process to melt the copper concentrates. The parameters of the polish concentrates (low iron and sulfur content, high organic carbon content) allowed producing the blister copper directly from the concentrate in the flash smelting furnace. The single-stage flash smelting process requires high oxygen potential and therefore produces the slag containing 12 – 16 wt.-% copper. Because of the high copper content, the slag needs to be decoppered. The technology concept developed by IMN Gliwice [1 – 3] is based on the reduction of the metal oxides in the electric furnace. The thermodynamic analysis [4 – 5] indicates that the copper can be removed from the slag to the concentration up to 0.003 wt.-%. The values obtained during the industrial process (the amount of copper left after the reduction is approximately 0.5 wt.-%) indicate that the calculated value is two times lower than the Cu concentration after decoppering, thus the Cu2O reduction in the electric furnace is not taking place under the thermodynamic equilibrium conditions.