Ion adsorption type rare earth ore is an important strategic and key metal resource, which was first discovered in Ganzhou, Jiangxi Province in the 1970s. Ion adsorption type rare earth ore is rich in medium and heavy rare earth elements, which are in short supply in the world, with low radioactivity ratio and high comprehensive utilization value. The ore had been widely used in many fields such as military industry, medical treatment and aerospace, and had become the focus of extensive attention at home and abroad. Ion adsorption type rare earth mineral deposit was a rare earth rich ore deposit. After weathering, the rare earth elements migrated under leaching and finally was adsorbed on the clay mineral surface in the middle and lower part of the weathering crust, forming an ionic rare earth deposit with unique adsorption characteristics. The special metallogenic characteristics and occurrence mechanism of rare earth elements led to complex characteristics of deposit geochemistry, physical and chemical properties of ores and element distribution law, which restricted the efficient development and utilization of ion adsorption type rare earth resources. At present, a large number of theoretical and practical studies were carried out on ion adsorption type rare earth ore at domestic and abroad. The microscopic occurrence mechanism of soil elements, the optimization of in-situ leaching process, the selection of leaching agents and the regulation of their properties provided a good theoretical and practical guidance for in-situ leaching. However, the existing studies mostly focused on the optimization of technological parameters in situ leaching process and the regulation of leaching seepage process, ignoring the natural enrichment rules and differentiation characteristics of rare earth elements in different parts of the orebody. And the vertical variation law of ore specific gravity, water content, pore structure and permeability along with orebody was not organically combined with the in-situ leaching process to guide the extraction of ion adsorption type rare earth ore. The ion adsorption type rare earth in Jiangxi Province was taken as the research object. This paper systematically studied the geochemical characteristics of the deposit, the spatial distribution of rare earth elements and the ore physical properties. The results showed that Ganzhou, Jiangxi Province was located in the hilly zone of subtropical zone. The climatic characteristics and tectonic plate movement made the rare earth elements in the weathering crust granite enriched and migrated in ionic form, and adsorbed on kaolinite, illite, halloysite clay minerals surfaces, light and heavy rare earth elements differentiation obvious regularity and yttrium rich characteristics of the significant application of rare earth deposits. In vertical direction along the orebody, the content of rare earth elements showed the distribution pattern of lean ore-rich ore-lean ore. Because there was a large amount of Fe(OH)3·nH2O in the topsoil layer, which made the interlayer acidity too strong, and clay minerals tended to form clusters and neutralize charges. In this acidic environment, rare earth cations continued to permeate and migrate with the water medium, resulting in the ore layer dilution. The whole weathered layer was mainly composed of a large number of clay minerals, and the interlayer was weak acidic and the content of K2O in the whole weathered layer was reduced, which was conducive to the precipitation of rare earth cations in the solution and the enrichment of mineralization in the appropriate position. Under the influence of their own properties, some of the rare earth cations continued to migrate to the semi-regolith under the action of water medium. Due to the change of environment and the sharp reduction of clay minerals in the semi-regolith, the adsorption capacity of rare earth ions was weakened. Compared with the whole regolith, the rare earth elements were more difficult to enrich. The highest rare earth content was in weathering layer, and the deposit type belonged to shallow voltaic type. In-situ leaching, the injection well depth should be controlled in the whole weathered layer. The density and water content of ore samples were positively correlated with the content of rare earth, while the permeability coefficient was weakly negatively correlated with the content of rare earth. The ion adsorption type rare earth ore in Ganzhou, Jiangxi Province had a heavy specific weight and high water content. Appropriate addition of anti-swelling agent could significantly alleviate the mineral expansion caused by the dissolution of interlayer colloids after the clay minerals absorbed water and avoided blocking the seepage pores. The overall permeability of the orebody was poor and grain size distribution of the ore was mainly coarse and fine grains, and the fine ores had high content of clay minerals and higher surface energy, so the adsorption capacity of rare earth elements was stronger, which was more conducive to the enrichment of rare earth elements. The leaching process was easy to occur fine-particle migration phenomenon. So in-situ leaching process should control the leaching agent velocity, concentration, viscosity, hydraulic gradient and other parameters, which could change the surface force between the leaching agent and mineral particles. In addition, the addition of permeability enhancers could wet the mineral surface, improve the hydrophilicity of the mineral surface, reduce the seepage resistance and enhance the seepage effect to improve the leaching efficiency of ion adsorption type rare earth ore. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.
