Laterite Nickel Ore Beneficiation
The geological structure of laterite nickel deposits is relatively complex, and the nickel content and mineral composition of different deposits are quite different. It is difficult to enrich by traditional beneficiation methods. At present, the beneficiation methods of laterite nickel ore include nickel-sulfur process, rotary kiln-submerged arc furnace process, sintering-blast furnace reduction process, direct reduction process, acid leaching process, etc.
The above-mentioned laterite nickel ore beneficiation is greatly restricted by the power supply, and there are problems such as high investment and high pollution. The use of chemical beneficiation processes such as acid leaching for laterite nickel ore beneficiation is the beneficiation direction of laterite nickel ore. Longzhong Heavy Industry conducts research on different types of laterite nickel ore, and adopts normal pressure acid leaching, pressure acid leaching, normal pressure + high pressure combined acid leaching to treat laterite nickel ore, and a good beneficiation effect can be obtained.
1. Atmospheric pressure acid leaching of 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. During the treatment, the laterite nickel ore is first ground into a certain concentration of ore slurry, and a certain concentration of acid is added, and the temperature is controlled to make the elements such as nickel, cobalt, iron, magnesium, aluminum in the ore leached, and then separated and washed for treatment. Then use alkali to neutralize the pulp to remove impurities such as magnesium, iron, and aluminum. After liquid-solid separation and washing, the obtained liquid is re-precipitated to obtain nickel-cobalt hydroxide. The remaining liquid is re-neutralized to remove calcium, and magnesium is returned to production and a port of discharge. The iron in the leaching solution of laterite nickel ore is converted into iron phosphate, which is further processed into lithium iron phosphate.
2. Pressure acid leaching process of laterite nickel ore
The pressure acid leaching process is suitable for the treatment of laterite nickel ore with high limonite content and low magnesium content. The laterite nickel ore is ground and prepared into a stable slurry, which is leached under a stable sulfuric acid concentration after preheating. During leaching, elements such as nickel, cobalt, iron, and aluminum 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 scheme, different processes can be used to produce high-quality nickel-cobalt hydroxide, nickel-cobalt sulfide, or nickel-cobalt sulfate crystals.
3. Atmospheric+high pressure combined acid leaching process
Atmospheric pressure and 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 main purpose of using the combined process of atmospheric leaching + high-pressure acid leaching to treat laterite nickel ore is to neutralize the excess acid in the leaching solution, thereby removing part of the ferric iron. The high-magnesium type laterite nickel ore is added to the low-magnesium type mineral in the acid leaching solution at normal pressure for two-stage high-pressure acid leaching, which can neutralize the free acid.