Nickel has the characteristics of high mechanical strength, good ductility, refractory and high-temperature resistance, and high chemical stability. Therefore, it is widely used in fields such as stainless steel and new energy, and has become an indispensable metal in the construction of modern systems. There are many types of nickel ores, and according to their mineral properties, nickel ores are mainly divided into sulfide copper nickel ores and oxide nickel ores, with completely different beneficiation and processing methods. This article will discuss the beneficiation method of sulfide copper nickel ore.
Copper in copper nickel ore mainly exists in the form of chalcopyrite, while nickel mainly exists in the form of free sulfide nickel such as nickel pyrite, needle sulfide nickel ore, and purple sulfide nickel iron ore. A considerable amount of nickel exists in the form of "isomorphism" in pyrrhotite, and there is also a small amount of nickel silicate. The type of sulfide copper nickel ore is mostly magma melting type copper nickel ore. When the nickel content is above 3%, it is rich ore and can be directly smelted, while when the nickel content is below 3%, beneficiation treatment is required. In mineral processing methods, flotation is the main method, and gravity and magnetic separation are usually auxiliary.
The sulfide copper nickel ore dressing and gravity separation method utilizes the density difference of minerals to achieve mineral separation through gravity separation.
The magnetic separation rule utilizes the magnetic differences of minerals to separate magnetic minerals from non-magnetic minerals through the action of a magnetic field. In the process of nickel ore magnetic separation, effective separation can be achieved by adjusting the magnetic field strength and the operating speed of the magnetic separator based on the magnetic differences between nickel ore and impurities.
There are different flotation methods for sulfide copper nickel ore, including priority flotation, mixed flotation, and mixed optimal flotation process. Priority flotation is suitable for ores with high copper content and can directly obtain copper concentrates with low nickel content; Mixed flotation is suitable for ores with low copper content, and copper nickel concentrate is sorted after mixed flotation. The mixed optimization flotation process combines the advantages of the first two, first conducting copper nickel mixed flotation, and then sorting out copper concentrate with low nickel content and nickel concentrate with copper content to improve flotation efficiency and resource recovery rate. A basic principle for determining the flotation process is to allow copper to enter the nickel concentrate rather than nickel to enter the copper concentrate as much as possible, because nickel in the copper concentrate is lost greatly during the smelting process, while copper in the nickel concentrate can be recovered more completely.
In the beneficiation process, we need to pay special attention to different types of nickel minerals and use different flotation reagents and process conditions for them. Nickel pyrite, nickel sulfide nickel ore, and nickel containing magnetite can be effectively flotation by advanced xanthates such as butyl or pentyl. The flotation properties of these minerals are between chalcopyrite and magnetite, so good flotation results can be achieved under different medium conditions. In addition, lime is a commonly used inhibitor that has a good inhibitory effect on pyrrhotite, while excessive lime is required to inhibit nickel pyrite and nickel sulfide. Meanwhile, copper sulfate is an activator of nickel pyrite and magnetite, which helps to improve flotation efficiency.
In practical operation, the beneficiation method may need to be adjusted and optimized according to specific circumstances. Due to factors such as the properties and distribution differences of ores, the flotation effect may vary. Therefore, we need to develop corresponding process flow and beneficiation methods based on the conditions and characteristics of each individual mine to improve the nickel ore recovery rate.
