4 processes for copper oxide beneficiation

Copper oxide ore is formed by long-term oxidation of copper sulfide minerals and is often found in the oxidation zone of the surface part of the ore deposit. Due to the extremely complex oxidation process, the mineral composition and structural structure of copper oxide ore are also relatively complex. The selectivity of this type of ore depends on factors such as the type of mineral, the composition of the gangue minerals, the symbiotic relationship between the minerals and the gangue, and the amount of mud.

At present, the main treatment methods for copper oxide ore include flotation, separation, leaching and combined methods. Among them, flotation is widely used because of its environmental protection, low cost and simple process.

Flotation method of copper oxide ore

1. Direct flotation of copper oxide

Direct flotation is a method of directly separating the target mineral using a collector without pre-treatment of the mineral. This method is the earliest method used in copper oxide flotation. It has certain limitations and is suitable for copper oxide with simple mineral composition and uncomplicated properties. When the direct flotation method is used to treat copper oxide ore, the selection of collectors and the amount of ore mud will directly affect the separation effect.

Although direct flotation has been used for a long time, it has high requirements for the ore to be processed. The presence of ore slime and calcium magnesium carbonate mineral content will affect its flotation effect, and the selectivity is poor. In addition, the direct flotation method has great limitations. It is mostly used for minerals with good floatability such as malachite. Minerals with poor floatability such as chrysocolla are difficult to float directly.

2. Copper oxide sulfide flotation method

Compared with direct flotation, sulfide flotation is a method of pre-treating copper oxide with a sulfiding agent (sodium sulfide, potassium sulfide, etc.) and then using a collector to sort it. The original ore reacts with the sulfiding agent, and the copper oxide surface quickly adsorbs HS- or S2- and forms a metal sulfide film, which in turn strengthens the adsorption of the collector and enhances the hydrophobicity of the mineral surface, achieving selective and efficient flotation of copper oxide minerals.

3. Separation flotation of copper oxide

The copper oxide ore is crushed to an appropriate particle size, and a certain amount of halide (salt) and reducing agent (coal powder) are added to roast under high temperature conditions. The copper in the copper oxide ore reacts with hydrogen chloride to generate volatile copper chloride, which is adsorbed on the surface and reduced to copper. The final flotation process is the separation flotation method.

Compared with the first two methods, the separation flotation method consumes more heat energy, has higher costs, and has poor working conditions. Although it can better recover valuable metals such as copper and silver from the ore, considering economic factors, it is rarely used in actual production. Therefore, this method has not been widely used.

4. Combined beneficiation and smelting of copper oxide

The combined beneficiation and smelting process is a separation process that combines metallurgy with flotation. When the ore properties are complex or the grade of low-grade copper oxide ore is difficult to be recycled by flotation or leaching, the use of the combined beneficiation and smelting method can often achieve better results.

For copper oxide ores with extremely fine embedded particles, researchers have found that the ammonia leaching-sulfide precipitation-flotation method, that is, the slurry with sulfur powder added is pressurized and leached in the presence of ammonia and carbon dioxide. Ammonia and carbon dioxide react with minerals to form copper amine complexes, which are dissolved in the slurry and immediately precipitated by sulfur atoms to form new copper sulfide. The slurry is directly distilled to recover ammonia and carbon dioxide without solid-liquid separation, and then the copper sulfide is recovered by conventional flotation, which can obtain better sorting indicators.

In summary, when the ore properties are complex, the grade is low, and the binding rate is high, the use of a single flotation method or chemical beneficiation method cannot obtain ideal sorting indicators. The use of the combined beneficiation and smelting method can give full play to the advantages of the separation process, thereby efficiently and low-cost development of difficult-to-treat ores.