With the continuous increase in demand for nickel ore and the deepening of the development of nickel sulfide ore, the development of laterite nickel ore has gradually become a new trend in the development of nickel ore. 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 mineral processing methods. The current mineral processing 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.
Three methods of mineral processing of laterite nickel ore
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 mineral processing for laterite nickel ore mineral processing is the mineral processing direction of laterite nickel ore.
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.
Pressure acid leaching process of laterite nickel ore
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.
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, which needs to be neutralized in the later purification process of the leaching solution, which will have varying degrees of impact on the subsequent impurity removal operations. Based on the two processes of high-pressure acid leaching, a two-stage leaching process is studied. The combined process of atmospheric pressure leaching and high-pressure acid leaching is used to treat laterite nickel ore. The main purpose is to neutralize the excess acid in the leaching solution, 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.
In actual production, different lateritic nickel ores have different properties and mineral compositions, and cannot be copied blindly. It is recommended that mine owners do a good job of mineral processing tests, clarify the nature of the deposit, and formulate a mineral processing plan in a targeted manner to obtain ideal economic benefits.