China Nonferrous Metallurgy

Firstly, thermodynamic calculation was used to obtain the relationship between the Gibbs free energy and time of the main reaction when smelting Kaldor slag. It showed that under the condition of temperature 750~1500℃, with coke as reducing agent and limestone as flux, all main reactions could occur, and finally copper-nickel alloy and calcium silicate slag could be obtained. On this basis, combined with difference in reducibility of different elements in Kaldor slag, granular coal was used as a reducing agent, and Kaldor slag was selectively reduced and smelted in a DC electric arc furnace to obtain qualified copper-nickel alloy and discarded slag. The test results showed that under the conditions of smelting temperature of 1420℃, reducing agent rate of 10%, flux rate of 15%, and settling time of 60 minutes, high-grade copper-nickel alloys were obtained, and the alloy grades were all greater than 90.00%; the recovery rates of copper and nickel were both greater than 98.50%, and the content of nickel and copper in the slag were reduced to 0.15% and 0.32% respectively, achieving one-step extraction of valuable metals from the slag. The research is conducive to improving the secondary resource recovery rate of non-ferrous metals, and lays a theoretical and practical foundation for smelting of Kaldor slag in the DC electric arc furnace.