Lateritic nickel ore beneficiation technology and process flow

 The geological structure of laterite nickel ore is relatively complex, and the nickel content and mineral composition of different deposits are very different. It is difficult to enrich through traditional beneficiation methods. The current beneficiation methods of laterite nickel ore include nickel-sulfur process, rotary kiln-submerged arc furnace process (RKEF), sintering-blast furnace reduction process, direct reduction process, acid leaching process, etc.

Using nickel-sulfur technology, rotary kiln-submerged arc furnace process (RKEF), sintering-blast furnace reduction process, direct reduction process and other pyrometallurgical methods to enrich laterite nickel ore is limited by power supply, and there are problems such as high investment and high pollution. , using acid leaching and other chemical beneficiation processes for laterite nickel ore beneficiation is the beneficiation direction of laterite nickel ore. According to the research on different types of laterite nickel ore, the use of atmospheric pressure acid leaching, pressurized acid leaching, normal pressure + high pressure combined acid leaching to treat laterite nickel ore can obtain good beneficiation effect.

1. Atmospheric pressure acid leaching method for laterite nickel ore

Atmospheric pressure acid leaching is suitable for treating laterite nickel ore with high magnesium content, and sulfuric acid and hydrochloric acid are generally used as leaching agents. When processing, the laterite nickel ore is first ground and then made into a certain concentration of pulp, and a certain concentration of acid is added, and the temperature is controlled to leach elements such as nickel, cobalt, iron, magnesium, aluminum in the ore, and then processed after separation and washing; Use alkali to neutralize the pulp to remove impurities such as magnesium, iron, aluminum, etc. After liquid-solid separation and washing, the obtained liquid is re-precipitated to obtain nickel hydroxide and cobalt; the remaining liquid is neutralized to remove calcium, and magnesium is returned to production and production. part of the discharge. The iron in the laterite nickel ore leaching solution is converted into iron phosphate, which is further processed into lithium iron phosphate.

2. Laterite nickel ore pressure acid leaching process

The pressure acid leaching process is suitable for treating lateritic nickel ore with high limonite content and low magnesium content. First, the laterite nickel ore is finely adjusted to a stable concentration of slurry, and after preheating, leaching is carried out under a stable sulfuric acid concentration. During leaching, nickel, cobalt, iron, aluminum and other elements are dissolved together. After separation and washing, impurities such as iron and aluminum enter the slag, while nickel and cobalt remain in the solution. According to the requirements of the product plan, different processes can be used to produce high-quality nickel-cobalt hydroxide, nickel-cobalt sulfide or nickel-cobalt sulfate crystals.

3. Atmospheric pressure + high pressure combined acid leaching process for laterite nickel ore

Atmospheric pressure-high pressure two-stage acid leaching treatment of laterite nickel ore can be used for ores with different contents of magnesium in one ore body. The acid leaching process will produce excess acid after treatment, and neutralization treatment is required in the later purification process of the leaching solution, which will have varying degrees of impact on the subsequent impurity removal operations. On the basis of this process, a two-stage leaching process was studied, and the combined process of atmospheric pressure leaching and high-pressure acid leaching was used to treat laterite nickel ore. The main purpose was to neutralize the excess acid in the leachate, thereby removing part of the ferric iron. Add low-magnesium type minerals to the normal-pressure acid leaching solution of high-magnesium laterite nickel ore for two-stage high-pressure acid leaching, which can neutralize free acid.