Five Major Chemical Methods for Processing Refractory Copper Oxide Ores

Floating flotation can treat most copper oxide minerals, but for low-grade copper oxide ores—particularly those where the primary copper-bearing minerals are chalcopyrite and cuprite—flotation often fails to achieve satisfactory results. In such cases, chemical beneficiation methods may be employed to process the copper oxide minerals.

(1) Acid Leaching of Copper Oxides

Acid leaching serves as the primary hydrometallurgical approach for treating refractory copper oxide ores. This method is applicable when the ore contains only minimal carbonate gangue.

(2) Copper Oxide Ammonia Leaching

Ammonia leaching is suitable for treating low-grade copper oxide ores containing substantial alkaline, siliceous, and iron gangue minerals, along with significant clay content. Copper extraction via ammonia leaching involves using ammonia-containing solvents—typically ammonia or ammonium salts as leaching agents—to dissolve the copper metal and its compounds present in the ore material into solution. Subsequently, appropriate methods are employed to precipitate the copper. When treating low-grade and difficult-to-process oxidised copper minerals, this method achieves high copper recovery rates, and the reagents can be regenerated and recycled. The ammonia leaching method is not only suitable for oxidised copper ores but also possesses unique advantages in processing copper sulphide concentrates, complex copper sulphide ores, scrap copper, steel furnace slag, tailings, and other copper-bearing materials.

(3) Bacterial Leaching of Copper Oxides

Bacterial copper leaching constitutes a biological mineral processing technique utilising microbial action. Through bacterial activity, it accelerates the extraction of valuable metals from metallic minerals and ores. This method is suitable for treating silicate-type copper oxide ores, as well as copper sulphide and oxide ores with relatively low carbonate content.

(4) Dissociation-Floating Process for Copper Oxides

The separation-flotation method is suitable for treating copper oxide ores containing significant quantities of chalcopyrite and cuprite. The separation process is relatively complex, involving repeated gas-phase and solid-phase reactions. Regarding the mechanism and kinetics of the separation process. The dissociation process occurs in three stages: first, at 700°C, salt reacts with crystalline water in the ore to produce hydrogen chloride; second, hydrogen chloride reacts with copper oxide minerals to form volatile cuprous chloride; finally, cuprous chloride vapour is adsorbed onto carbon particles, where hydrogen reduces it to sponge copper while regenerating hydrogen chloride gas.

(5) Integrated Beneficiation-Smelting Process for Copper Oxides

The integrated beneficiation-metallurgy method combines the advantages of mineral processing and metallurgical techniques to treat copper oxide ores. This approach yields excellent results for refractory copper oxide ores. Based on the properties of different minerals within the ore, flotation is employed to recover easily floatable copper sulphide minerals, while hydrometallurgy is used to recover readily leachable copper oxide minerals. The complementary strengths of these two methods achieve high recovery rates throughout the entire process.