Laterite nickel grade is low and complicated etc., the output product is different, which makes that the production of nickel is more complicated, and the method is varied. Generally it can be divided into pyrogenic process, wet, metallurgy combined with beneficiation.
1 pyrogenic process
At present pyrogenic process includes reduction smelting ferronickel production and reduction smelting of sulfide production of nickel matte.
Reduction smelting ferronickel smelting process is commonly used, the rotary kiln- electric furnace reduction smelting process is a smelting process widely used in laterite smelting plant, which is reliable and mature. The main processes include drying, roasting, pre reduction, smelting and refining of electric furnace. The raw ore contains a lot of adsorbed water and crystal water, so preparation before melting is dehydration and drying. It is generally to remove the attached water in the drying kiln, in the longer rotary kiln under the higher temperature achieve the roasting and pre reduction, crystal water is further removed.
Rotary kiln-electric furnace smelting process for processing various types of nickel oxide, molten pool can reach high temperature and it is easy to control temperature, suitable for processing difficult garnierite melting, the furnace raw materials are not strictly required. slag contains less valuable metal, production is easy to control, easy to operate, easy to realize mechanization and automation.
2 Wet process
Copper and cobalt content is higher in laterite nickel ore, in order to effectively extract other valuable metals and reduce energy consumption, the use of wet process to process is more reasonable. Because of the difference of MgO content in different ore, the leaching procedure should be treated differently by wet process. When the MgO content in the ore is low, the leaching process can be leached by sulfuric acid; When the content of MgO in the ore is higher, the leaching process should be used in the leaching process.