More than 60% of metal nickel ore resources are from copper nickel sulfide deposits. The chemical composition and mineral composition of this type of deposits are relatively simple. The main useful elements are nickel, copper, cobalt and platinum group elements. Some deposits are also associated with rare and precious metals such as gold, silver, palladium, which have good recycling value.
According to different ore types, mineral content and associated noble metal content, copper nickel sulfide ores are also different. At present, the applicable beneficiation methods include flotation, gravity separation and leaching.
Flotation method is the main method for separating copper nickel sulfide ores. The commonly used process flow is preferential flotation, mixed flotation, flash flotation, etc. floatable flotation and chemical control flotation.
Priority flotation is mainly aimed at ores with high copper content, low nickel content and simple properties. The process of "floating copper to suppress nickel" is usually adopted. The purpose of copper nickel separation is achieved by adding inhibitors of nickel sulfide minerals and efficient copper collectors. Copper concentrates with low nickel content and qualified nickel concentrates can be directly obtained.
Mixed flotation is suitable for the treatment of copper nickel sulfide ores with more magnesium silicate gangue minerals that are easy to float. Generally, the copper and nickel minerals in the mineral are floated together to obtain mixed copper nickel ore, and then the mixed ore is made into high nickel matte by flotation or smelting, and then the high nickel matte is grinded and de medicated again, and copper concentrate and nickel concentrate are separated by nickel suppression and copper flotation.
Flash flotation is suitable for copper nickel ore with uneven particle size. When copper nickel ore concentrate cannot be effectively obtained by general flotation, it is necessary to pre select and float a part of useful minerals that have been monomer dissociated or meet the particle size requirements through flash flotation before conventional flotation operation, which can effectively avoid the loss of useful minerals due to overgrinding, and realize the early recovery of useful minerals, which can not only improve the recovery rate of useful minerals, but also reduce the load circulation volume of the grinding circuit, reduce steel consumption and energy consumption.
The equally floatable flotation can also be called the separate mixed flotation method, which is suitable for the treatment of micro fine low-grade copper nickel sulfide ores. According to the different floatability of useful minerals, it is divided into two parts, namely, easy flotation and difficult flotation, and then the copper concentrate and nickel concentrate are separated according to the process flow from easy to difficult.
Electrochemical control flotation is to adopt the method of chemical agent control to change the electrochemical characteristics of flotation pulp, adjust the floatability of minerals, and realize the flotation separation of minerals. There are three potential control flotation modes:
The oxidation process of copper nickel sulfide mineral surface in grinding flotation process is controlled by oxidant;
By adjusting the pH value of the pulp, the electrochemical characteristics of the surface of copper nickel sulfide minerals are controlled to provide a reasonable flotation pulp environment;
Chemical agents are added to prevent excessive oxidation of copper nickel sulfide minerals during flotation.
However, potential control flotation will increase the amount of redox agent, which is unfavorable for subsequent flotation. In addition, installation and maintenance costs are high.
The gravity concentration method of copper nickel sulfide ore is actually a method of separating the dense and disseminated copper nickel ores by gravity concentration, separating the minerals in the form of heavy minerals and light minerals, and then flotation each mineral separately.
However, gravity separation is usually only used as an auxiliary beneficiation method, which can effectively reduce costs and recover useful ingredients to a large extent.
The leaching method is mainly suitable for treating some copper nickel sulfide ores with complex mineral composition and fine embedded particle size. Copper and nickel are separated by pressurized ammonia leaching hydrogen reduction nickel powder, acidification roasting leaching, pressurized acid leaching displacement flotation, preoxidation roasting selective reduction ammonia leaching and other methods. According to the mineral properties and characteristics, this series of methods selectively cultivate bacteria, and then use the biological oxidation of bacteria to leach useful minerals.
These are some beneficiation methods that can be applied to copper nickel sulfide ores. In the practice of the concentrator, according to the different properties of copper nickel sulfide ores, their beneficiation methods are also different. It is suggested that the beneficiation methods should be carried out first, and the suitable beneficiation methods of copper nickel sulfide ores should be customized according to the test results, so as to obtain an ideal rate of return on investment.
