Nickel ores are mainly divided into copper-nickel sulfide ore and nickel oxide ore. Their beneficiation and smelting processes are completely different. Today, the smelting process of the former is mainly introduced.

   Method of stone selection

   Flotation is the most important method for the beneficiation of copper-nickel sulfide ores, while magnetic separation and gravity separation are usually the auxiliary beneficiation methods. Collectors and foamers are often used for flotation of copper sulfide ores. A basic principle for determining flotation process is that copper can enter nickel concentrate rather than nickel. Because the copper concentrate is lost greatly in the smelting process, and the copper in the its concentrate can be recovered completely. Copper-nickel ore flotation has the following four basic processes.

   1) Direct priority flotation or partial priority flotation process: When the copper content in ore is much higher than that in nickel, this process can be used to separate copper into a separate concentrate. The advantage of this process is that the copper concentrate with lower nickel content can be obtained directly.

   2) Mixed flotation process: Used to separate ore containing less copper than nickel, the obtained copper-nickel mixed concentrate is directly smelted into high matte.

   (3) Mixing-optimizing flotation process: flotation of copper and nickel from ore mixture, and separation of copper concentrate with low nickel content and nickel concentrate with copper from mixed concentrate. The concentrate was smelted to obtain high matte, which was then flotation separated.

  4) Mixing-preferential flotation and recovering part of nickel from tailings of mixed flotation: When the flotability of various minerals in ores varies greatly, the nickel-bearing minerals with poor flotability are further recovered from tailings after copper-nickel mixed flotation.

   Smelting of Nickel Sulfide Ore

   The selection of process flow depends on the type of raw materials, composition and product requirements. Sulfide ores are mostly smelted by matte-making. Different pyrometallurgical processes are used to produce low-nickel matte from various nickel sulfide ores. Then low-nickel matte is converted into high matte, i.e. sulfide and copper sulfide alloys. High matte is then refined by different methods in a refinery to produce different nickel products.

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