A Detailed Explanation of Common Copper Ore Beneficiation Processes

Copper possesses excellent electrical and thermal conductivity, wear resistance and tensile strength, making it highly versatile and widely used in numerous sectors such as defence manufacturing, mechanical engineering, construction and electrical equipment. With the continuous growth in industrial demand for copper, efficient and cost-effective ore beneficiation technologies for various types of copper ore have become increasingly critical. For copper ores of different compositions and types, such as oxidised copper ores and mixed copper ores, the industry has developed a range of mature separation processes, including flotation-hydrometallurgy, ammonia leaching-sulphide precipitation-flotation, emulsion flotation and dissociative flotation, which can be selected according to the specific properties of the ore.

I. Flotation-Hydrometallurgy

Hydrometallurgy is a highly practical mainstream process in copper ore beneficiation, primarily divided into acid hydrometallurgy and ammonia hydrometallurgy, with the choice of process based on the mineral composition of the ore. For silicate-type copper ores, acid hydrometallurgy is suitable, offering mature technology, low costs and outstanding economic efficiency; for carbonate-type copper ores, ammonia hydrometallurgy is employed, providing more stable separation results. For complex mixed copper ores and oxidised copper ores, it is necessary to first add reagents such as sodium sulphide to subject the ore to sulphidation modification, converting difficult-to-process oxidised copper into easily processable sulphide copper. This is then combined with flotation to achieve concentration; during flotation, xanthate is typically selected as the collector to ensure separation efficiency.

II. Ammonia Leaching – Sulphidation Precipitation – Flotation Process

This process is specifically designed for carbonate-type copper ores and offers exceptional adaptability. The core stages comprise ammonia leaching modification, sulphidation precipitation and flotation enrichment. During production, the ore is first ground to the required particle size, mixed uniformly with powdered sulphur, and then immersed in an ammonia solution to undergo a reaction. Under the action of the ammonia solution, the copper oxide and carbon dioxide in the ore react with the ammonia water. Subsequently, through the evaporation of the ammonia solution, sulphide ions are precipitated, forming high-purity copper sulphide particles. Finally, in a weakly acidic environment with a pH of approximately 6, flotation is carried out on the copper sulphide precipitate to efficiently recover copper minerals, effectively addressing the challenges of high processing difficulty and low recovery rates associated with carbonate copper ores.

III. Flotation Method

The emulsion flotation method is a refined separation process for complex copper ores, achieving precise separation through surface modification of the minerals. During operation, copper minerals are first subjected to oxidation or sulphidation pretreatment, followed by the addition of acrylic polymers to suppress gangue minerals. This is combined with complexing agents such as thiophenylbenzazole and diphenylguanidine to form a stable, oil-loving film on the surface of the copper minerals. Subsequently, a non-polar emulsion is introduced, significantly enhancing the hydrophobicity of the copper minerals. This allows them to remain stably suspended in the pulp, ensuring complete separation from gangue impurities and ultimately achieving the final concentration stage. This process offers high selectivity, effectively reducing gangue carryover and improving the grade of the copper concentrate.

IV. Dissociation-Floating Method

The dissociation-floating method is primarily suitable for difficult-to-process copper oxide ores and constitutes a composite process combining thermal modification with flotation. First, the copper oxide ore is crushed, mixed thoroughly with sodium chloride and pulverised coal in a specific ratio, and fed into a roasting furnace for roasting at a constant temperature of approximately 850°C. Under high-temperature conditions, the copper components are converted into gaseous copper chloride. Upon cooling, the copper chloride is reduced to metallic copper and adsorbed onto the surface of carbon particles. Finally, xanthate is used as a collector, and metallic copper can be efficiently recovered through a conventional flotation process. This process offers high stability and is highly effective in upgrading low-grade, difficult-to-process oxidised copper ores.

In summary, the mineral structures and occurrence states of different types of copper ores vary considerably, and the corresponding beneficiation processes each have their own specific focus. In actual production, it is necessary to flexibly match separation technologies based on ore composition and mineral types. This can effectively improve copper resource recovery rates, reduce beneficiation costs, and achieve the efficient utilisation of copper ore resources.