Abstract:
Gallium metal resources are dominant resources in China, but gallium reserves in China are gradually declining with increasing global demand.This study systematically collected the research and exploration results pertaining to gallium-rich deposits in China and preliminarily summarized the distribution, metallogenic mechanisms, and prospecting directions of gallium-rich deposits in China.The results indicated that gallium ore in China is mainly associated with bauxite, coal, and lead-zinc mining, with gallium in bauxite being the most important.According to the different modes of mineralization, gallium-rich deposits of industrial value in China can be divided into five types of associated deposits, sedimentary bauxite, accumulative bauxite, lateritic bauxite, coal mine deposits, and Mississippi Valley-type (MVT) lead-zinc deposits.The spatiotemporal distributions of these different types of gallium deposits were summarized.In terms of time, gallium-rich deposits in China developed in the Proterozoic, Paleozoic, Mesozoic, and Cenozoic, but mainly in Carboniferous–Triassic, Jurassic–Cretaceous, and Quaternary.Among these, gallium-rich bauxite mainly formed in the Carboniferous, Permian, and Quaternary, with the Carboniferous period being the most important.Gallium-rich lead-zinc deposits mainly formed in the Sinian and Cambrian periods.Gallium-rich coal mines mainly formed in the Carboniferous and Permian periods.Spatially, the gallium-rich deposits in China are mainly distributed in seven zones: the Jin–Yu metallogenic zone, Youjiang metallogenic zone, southwest metallogenic zone of the Yangtze landmass, Sichuan–Yunnan–Guizhou metallogenic zone, western Hunan–West Hubei metallogenic zone, eastern Hunan–West Jiangxi metallogenic zone, and the northern margin of the North China landmass.The different types of gallium-rich deposits have different metallogenic mechanisms.Generally, gallium-rich bauxite forms under weathering and sedimentation.Gallium and aluminum often exist in isomorphic forms.Gallium-rich coal mines form as a result of biochemical deposition.The gallium often exists in inorganic, organic, and mixed forms.In China, it is mainly hosted in inorganic form within boehmite, diaspore, and other minerals.Gallium-rich lead-zinc ore forms from hydrothermal fluids.Gallium in these deposits often substitutes within the lattice of sulfide minerals, dominantly sphalerite.Based on the mineralization, enrichment processes, and geological backgrounds of the different gallium deposits, this study established ideal models of gallium-rich deposits and integrated ores in coal mines, lead-zinc mines, and bauxite and considered the prospects of these deposits.Prospecting directions and key prospecting areas were proposed.The prospecting of sedimentary and accumulative bauxite should be the main direction, but other associated gallium deposits such as those of coal mines and lead-zinc mines can be considered.