6 Processes for Oxidized Copper in Copper Ore

Depending on the properties of oxidized copper ores, the oxidized copper ore beneficiation methods are divided into direct flotation and sulfide flotation, mainly including fatty acid flotation, emulsion flotation, chelating agent-neutral oil flotation, etc., which are often used for oxidized copper ores with simple structure and relatively simple properties. 

For oxidized copper ores that are more difficult to select, leaching process can be used for treatment. At the current technical level, acid leaching and ammonia leaching technologies for oxidized copper are relatively mature and widely used, but the effect is still not ideal when treating fine particles that are difficult to select. 

1. Emulsion flotation method

This method mainly involves first sulfiding the copper oxide minerals, then using acrylic polymers and sodium silicate to inhibit gangue, and then adding complexing agents such as benzotriazole, toluyltriazole, mercaptobenzoxazole, and diphenylguanidine to form a stable lipophilic mineral surface, and then covering its surface with non-polar oil emulsions such as kerosene, diesel, and gasoline to form a strongly hydrophobic floatable state, and firmly adsorbing on the bubble surface to float and complete the separation.

2. Fatty acid method

Fatty acids and their soaps are suitable for the separation of malachite and azurite. Within a certain length range, the longer the hydrocarbon chain, the stronger the capture ability of its fatty acid (salt) and the less the amount used; in production practice, mixed, saturated or unsaturated carboxylic acids of C10-C20 are often used. Generally, water glass, sodium carbonate and phosphate are used as gangue inhibitors and slurry adjusters, but this method has certain limitations and is only applicable to siliceous copper oxide ores whose gangue is not carbonate; when the ore contains a large amount of iron and manganese minerals, its sorting index will deteriorate.

3. Leaching-precipitation-flotation method

This method is suitable for treating oxidized copper ores such as chrysocolla that are difficult to float or have poor sorting indexes. Because copper oxide minerals are relatively easy to dissolve in acid, the ore is ground to monomer dissociation, leached with dilute sulfuric acid with a concentration of 0.5-3%, and then replaced with iron powder to precipitate metallic copper. Then, in an acidic medium with a pH of 3.7-4.5, double yellow medicine or cresol black medicine is used to capture and precipitate metallic copper and undissolved copper sulfide minerals.

4. Ammonia leaching-sulfide precipitation-flotation method

This method is suitable for treating difficult-to-select oxidized copper ores whose gangue is carbonate. After the ore is finely ground, sulfur powder is added, and then ammonia leaching is performed. When copper oxide reacts with NH3 and CO2, it is precipitated by sulfur ions to form new copper sulfide particles. Then the ammonia is evaporated and the copper sulfide is floated by the general flotation method of copper sulfide ore.

5. Separation-flotation method

The essence of this method is to mix ore of appropriate particle size, coal powder (reducing agent) and salt (chlorinating agent) in a certain ratio, heat it to 700-800℃, and generate copper chloride that evaporates from the ore, and then is reduced to metallic copper by carbon and enriched on the surface of carbon particles. Then it is separated from the gangue by flotation. The process indicators obtained by this method are good, but the cost is very high. It is still in the industrial experimental stage.

6. Flotation-hydrometallurgy

Many oxidized copper ores and mixed copper ores are more or less difficult to select and some are easy to select. In this case, flotation is first used to recover the easily selected oxidized ore, and then the tailings or middlings are sent to hydrometallurgy.

Since the properties of ores are different, different types of copper mines use different flotation processes and flotation reagents. It is recommended that mineral processing companies conduct mineral processing experiments before mineral processing, and select appropriate mineral processing processes and reagent systems based on the properties o