Copper oxide and copper sulfide flotation reagent selection

Copper is a non-ferrous base metal found in the earth's crust at an average level of 50 ppm. The average grade of copper deposits available for mining is approx. 0.4% open pit mine and 1-2% Cu underground mine, as well as many other valuable minerals and gangue minerals.

Flotation is the most widely used traditional technology for beneficiation of copper, especially sulfide minerals. Flotation is performed using different reagents and involves differences in the physical and chemical surface properties of copper minerals and gangue, separating them from each other by using various surfactants. In addition to flotation, gravity separation, leaching and selective flocculation are also used in the processing of copper ores.

1. Copper sulfide mineral

The flotation of copper sulfide ores mainly uses mercaptan collectors, such as xanthate, dithiocarbamate and dithiophosphate, which form different surface products in different copper sulfide minerals. The impact of collectors on copper sulfide was evaluated using recovery and flotation rate criteria. Flotation of copper sulfide minerals with mercapto collectors was found to be effective in the following order: xanthate > dithiophosphate = thiocarbamate > dixanthogen.

2. Copper oxide mineral

Froth flotation of copper oxide ores is a complex method and requires a sulfidation stage. Copper oxide ore has a thick hydration film surface and is difficult to contact with bubbles, which means that the flotation reaction of oxide is inferior to copper sulfide ore both technically and economically. In addition, the enrichment of copper oxide ores with low dissolution rates generally uses froth flotation after the sulfidation stage or a mixture of flotation and hydrometallurgy. Copper oxide minerals such as malachite and cuprite can be efficiently recovered using alkyl hydroxamates as collectors.

3. Mixed copper ore

The copper oxide deposit in Dali, Yunnan, China, contains 0.69% copper (0.46% and 0.23% copper in the form of copper sulfide and oxide minerals, respectively) and 11.24 g/t silver. The ore is upgraded through a sulfidation process followed by xanthate collector flotation. During the experiment, sodium sulfide was used as the vulcanizing agent (100 g/t), and butyl xanthate and dibutyl ammonium dithiophosphate were used as the combined collector.

Through the closed-circuit test, a copper concentrate with a copper grade of 18.34% and a copper recovery rate of 70.13% was obtained.