Alternatives of Copper (I) Oxide Reduction in a Copper Slag Cleaning Furnace

Abstract

As environmental, energy saving, and legislation considerations are becoming ever more important, there is evidently a demand for further improvement in slag handling and metal recovery practice. The metallurgical industry is initiating its actions into minimizing and processing of slags to achieve sustainable development and circular economy. Reduction of copper oxide is an important step of metal recovery and slag cleaning in copper production. This can be achieved by slag treatment with injected reducing agents. In this paper, it is presented a computational fluid mechanics model of tuyere and purging plug injection of reductants into slag that considers a first-order heterogenic chemical reaction to model copper oxide reduction. Using the model, it is possible to compare and optimize tuyere and purging plug arrangements in terms of time needed to reduce copper oxide content to a given value. Copper oxide reduction accomplished with the injection of different reducing media (oil, natural gas, and hydrogen) for several tuyere/plug arrangements in a slag refining furnace was simulated and the reduction performance using different reduction media was compared. It was shown that purging plugs, which may be installed at the deepest position in the furnace, create an improved gas flow pattern that results in a higher copper oxide reduction rate and decreasing in CO2 emission.KeywordsCopper-oxide reductionPurging plugsCO2 emissionDecarbonizationHydrogenReduction rate