Mechanism of Protective Cover and Melting Loss of Copper Melt

A high temperature resistance furnace was used for the preparation of oxygen free copper in the atmosphere of nitrogen to solve the problems of big covering agent (charcoal) consumption, high metal loss and heavy melt pollution in the process of copper smelting. By using X-ray diffraction (XRD) and scanning electron microscopy (SEM), the slag structure, composition, morphology, copper in slag, phase morphology and metal loss were studied under the protection of the covering agents of solid alumina film, borax-cryolite and borax-carbon black, and the influence of different coating agents on copper melt and slag composition was revealed, which provided the theoretical support for reducing metal loss and charcoal consumption in the copper-smelting process. Through XRD observation, it was found that phase of smelting slag prepared with no-covering agent and with the covering agent of solid alumina film were CuO and Cu₂O; while that with the covering agent of borax-cryolite consisted of CuF₂, Cu₂O, Cu(OH)₂, Na₃AlF₆; phase of smelting slag with covering agent of borax-carbon black were borax, Al₂O₃, CuO and solid carbon. SEM study indicated that all of the different covering agents had protective effects in the process of copper smelting; phase of smelting slag and slag losses were different with different schemes; the content of copper was high in the smelting slag formed under the covering agent of borax-carbon black, and metal loss was serious.