Thermodynamic modeling of copper ore processing into matte using borate ores

The cost of one ton of copper on the London Metal Exchange often reaches 9'000 USD. Such a high price necessitates measures aimed at maximizing the extraction of this metal into final products and minimizing losses. According to open sources, the total amount of copper in technogenic mineral formations of Kazakhmys Corporation LLP (Kazakhstan) is estimated at about 4 million tons. This study proposes measures to reduce copper losses from the pelletizing stage to smelting in metallurgical furnaces. Using full thermodynamic modeling, the effect of boron anhydride and borate ore on the processes of pelletizing, drying, roasting of copper ore concentrates, and matte production was investigated. It was found that the use of B₂O₃ is expected to increase the strength of wet pellets due to the formation of boron anhydride crystal hydrates (H₃BO₃), which bind ore particles. During drying, the hydrate loses water at 285 K, turning into boron anhydride, which melts at 723 K during roasting, forming a liquid phase. Upon cooling, this phase creates a solid sinter together with other ore components. Metallurgical processing of such boron-containing material is predicted to improve process performance and reduce matte losses due to the formation of low-viscosity, highly mobile furnace slags. The proposed borate ore contains montmorillonite, a clay mineral typical of bentonites, which ensures sufficient strength of wet pellets for transport from the pelletizing unit to the roasting equipment. The presence of low-melting borate ore in the pellets promotes the formation of a liquid phase during roasting, which solidifies into a strong sinter. As with B₂O₃, metallurgical smelting is expected to benefit from reduced matte losses due to the formation of lighter, more fluid slags. The calculations and modeling conducted confirm the high potential of the proposed approach for industrial implementation.