Evaluation of the Suitability of Various Biocarbon Types to Copper Slag Reduction/Cleaning

Various ways of lowering the carbon footprint of copper production are currently examined in the copper industry. One possibility is to use biocarbon instead of fossil carbon in copper slag reduction. Biocarbon is an umbrella term that comprises of widely differing materials; the original raw materials, production technologies as well as production process parameters may vary significantly. Reactivity has been identified as one important parameter in defining the suitability of a biocarbon to slag reduction. Therefore, a set of various types of biocarbons were characterized in terms of chemical composition, moisture, and microstructure, followed by measuring their reactivities in slag reduction. The measurements were conducted in a high-temperature graphite resistance furnace and the reactivity was based on the gas evolution kinetics when the reductant was introduced onto the surface of molten model (ilmenite) slag. The characteristics influencing the reactivity of the various biocarbon types are discussed and compared to metallurgical coke as a reference case widely used in industry nowadays. The reactivity experiments were complemented with reduction experiments of a larger scale in an induction furnace and the results of both methods were compared and discussed.