Adsorption Characteristics And Solute Transport Law Of Rare Earth Ions For Weathered Crust Elution-deposited Rare Earth Ores

To grasp the adsorbing characteristics of weathered crust elution-deposited rare earth ores and solute transport process of rare earth ions in leaching solution are of great significance for improving leaching rate of in-situ leaching mining.Firstly,various grain-sizes of weathered crust elution-deposited rare earth ore samples were obtained by sieving,and testing ionic REO grade,specific surface area,surface morphology and mineral composition etc of various ore samples,the adsorbing property for rare earth ions in the ore body was analyzed.Then through indoor column leaching experiments for the ore samples of different void ratio were carried out under constant head,the effect of void ratio on leaching rate and leaching cycle the ore resources was analyzed;and retardation factor and coefficient of hydrodynamic dispersion based on breakthrough curve were calculated.The results show that:(1)The mineral compositions of Xinfeng’s rare earth ore mine from southern Jiangxi province are kaolinite,k-feldspar,quartz,tourmaline,muscovite and garnet,and the total mass proportion of these 6 main mineral components reaches 94.82%.But the granularity of different mineral composition is obviously different,and the quality proportion of kaolinite and muscovite increases in small grain-size of rare earth ore.And the adsorption capacity of rare earth ion is positively correlated to the proportion of clay minerals such as kaolinite.(2)Based on that the adsorption capacity of rare earth ions in the concavities on the surface of ore bodies is a log-normal distribution with the aperture and grain-size,the model to analyze the relationship between the adsorption quantity of rare earth ions and the aperture of surface concavities is established.Then by using the model,the effective pore size of adsorption for Xinfeng’s rare earth ore mine in southern Jiangxi province is calculated to be 2.0~20.0 nm.(3)The leaching rate of rare earth resources for ore samples which are of different void ratios is about 90%.The larger void ratio of the ore sample is easier to penetrate,and its leaching cycle is shorter and residual rate of NH4+ is higher.Prolonging injecting time of underscreen water can effectively reduce the residual rate of NH4+.(4)For the ore samples of different void ratio,solute transport breakthrough curve is of different delay: the ore sample is easier to penetrate because of its larger void ratio,and its curve obviously shifts to the left;compared with NH4+ which participates in ion exchange and adsorption desorption,the breakthrough curve of the unreacted SO42-moves to the left.When the hydraulic gradient is 1.1 and using the first liquid injection mode,the retardation factor of ore samples which are of different void ratios is 1.16.