Experimental studies and pilot plant tests for acid leaching of low-grade copper oxide ores at the Tuwu Copper Mine

Tuwu Copper Mine is the largest mineral resource in Xinjiang. Due to the geographical and climatic conditions in the region, to date this resource has not been well exploited. Since 2010, the authors have been investigating the practicability of heap leaching for easy and effective copper recovery. The paper describes metallurgical studies and pilot plant tests conducted on Tuwu low-grade copper oxide ores. Laboratory tests have shown that heap leaching is suitable for these ores. The pilot plant was built in the Gobi Desert. The six heaps operated well at heights from 1.4 to 4.1 m. Detailed investigations of the permeability, copper leaching rate, acid consumption and water evaporation showed that heaps of − 40 mm ore leached for 68 days produced a copper leaching rate of up to 85.8%. Sulfuric acid consumption was 24.2 kg per ton-ore, and water consumption was 0.164 t per ton-ore, demonstrating that heap leaching - solvent extraction - electrowinning technology is feasible in the Gobi Desert.