Abstract
Nickel resources, as crucial strategic metallic mineral in China, exert profound impacts on national economic security, defense capabilities and resource sustainability. China has the largest demand for nickel in the world, but its nickel resources are scarce, accounting for merely 4.0 % of global totals, with approximately 90 % of them are difficult to mine copper nickel sulfide ores, and 10% are low-grade laterite nickel ores, resulting in significant import dependence. From a regional perspective, China's nickel resources are mainly distributed in the northwest, southwest, and northeast, with their retained reserves accounting for 76.8%, 12.1%, and 4.9% of the total national reserves, respectively. The main occurrence states of nickel ore resources are sulfide copper nickel ore and laterite nickel ore. The composition of sulfide copper nickel ore in China is basically similar, and the main minerals include nickel pyrite, needle sulfide nickel ore, purple sulfide nickel iron ore, red nickel ore, nickel containing magnetite, magnetite and chalcopyrite. Vein minerals mainly include serpentine, chlorite and talc. Nickel typically coexists with copper and cobalt in sulfide form, with froth flotation serving as the primary beneficiation method. This article mainly introduces five methods: bulk flotation, selective flotation, pre-rejection of gangue-flotation process, stage grinding-floating, flotation-gravity technology, which correspond to the treatment of sulfide copper nickel ore with different element contents and embedding relationships. The bulk flotation process has strong adaptability to ores, and the selective flotation process is suitable for sorting ores with copper grades higher than nickel grades, Pre-rejection of gangue-Flotation process is suitable for sorting ores with high vein content in the raw ore, while stage grinding-flotation process is suitable for sorting ores with complex component embedding in the ore; laterite nickel ore is divided into three parts: limonite layer, transition layer, and saprolite zones. Due to the differences in mineral composition and content of each layer, different sorting processes are required. The limonite layer has a higher content of iron and cobalt, lower content of silicon, magnesium, and nickel, and a more uniform mineral composition. Iron mainly exists in the form of goethite and hematite, while nickel is mostly present in ores containing silicon and magnesium using wet metallurgical processes; the transition layer has a content of various elements between the limonite layer and the humus layer. Nickel is mainly present in silicate minerals, with some present in iron ore species. To achieve effective recovery of valuable elements such as nickel minerals, it is necessary to use enhanced conditions such as acidity, high temperature, and reduction to fully expose each element to the reaction environment. Therefore, a wet pyrometallurgical combined process is suitable; the saprolite zones has a high content of silicon, magnesium, and nickel, low content of iron and cobalt, and extremely uneven mineral composition. The main mineral components of this layer are silicate minerals, followed by iron oxide. Using a wet process can lead to problems such as excessive dosage of chemicals, and the nickel content is high, with a melting point lower than that of iron oxide. Therefore, pyrometallurgical processes are mostly used. This article aims to provide a systematic overview of different types of nickel mineral resource sorting processes, analyze the advantages and disadvantages of each process, and propose prospects for improving the utilization of nickel ore resources, providing reference for the treatment methods of different nickel ores.
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