Study On The Effect Of Fine Particle Content On The Percolation Characteristics Of Rare Earth In Situ Leach Ore Dissolution Leach Solution

The microscopic pore structures of ionic rare earth mines with different soil layers or different fines contents lead to different permeability properties.In this paper,a rare earth mine in Dingnan County,Jiangxi Province,was selected as the experimental object,and the rare earth ore with different fine particle contents was prepared according to the measured basic physical parameters of the in situ soil,and water and magnesium sulfate solution were used as leaching agents to conduct permeation experiments,full particle size sieving experiments and indoor column leaching experiments to study the permeability coefficient,micro-particle migration and pore structure distribution of rare earth ore with different fine particle contents under the column leaching conditions of water and magnesium sulfate solution.The study investigated the permeability of rare earth ores with different fine-grained contents and their pore structure evolution mechanism under different leaching solution conditions.The main research contents and results are as follows:(1)In order to investigate the change law of permeability coefficient of rare earth ores with different fines content during the leaching process,indoor permeation experiments of rare earth ores with different fines content were carried out,and the correlation between state parameters such as fines content and initial permeability coefficient was found.The results showed that the permeability coefficients of rare earths increased first and then stabilized when the ore was leached with clear water,while the permeability coefficients decreased rapidly in the first 1-2 days when the ore was leached with magnesium sulfate solution,and then stabilized.The higher the content of fine grains,the smaller the permeability coefficients of rare earth layers and the whole,the smaller the rise or fall of permeability coefficients,and the longer the time to reach stability.In semi-logarithmic coordinates,the permeability coefficients show different degrees of inhomogeneous decrease with the increase of rare earth ore fines content,average particle size and inter-pore ratio.With the increase of rare earth ore inhomogeneity coefficient,the rare earth permeability coefficient decreases linearly.(2)In order to investigate the rule of particle gradation change of rare earth ore with different fine particle contents during the leaching process,full particle size sieving experiments of rare earth ore with different fine particle contents were carried out.The results showed that: after leaching with clear water,the fines attached to the surface of coarse particles decreased,and the higher the fines content of rare earth ore,the more obvious the reduction effect;the higher the fines content of rare earth ore,the higher the fractal dimension of particles in the upper,middle and lower layers,and the fractal dimension of each rare earth ore before leaching is higher than that of its upper,middle and lower layers after leaching.The fractal dimension of the upper,middle and lower layers after leaching with magnesium sulfate solution is consistent with the results of clear water leaching,but the fractal dimension of each rare earth ore before leaching is lower than that of the upper,middle and lower layers after leaching,and the effect of particle migration in the leaching process of each rare earth ore with fine grain content is not as obvious as that of clear water leaching,indicating that the higher the fine grain content of rare earth ore,the smaller the effect of leaching activity on its particle migration.(3)In order to investigate the pore structure evolution of rare earth ores with different fines,column leaching experiments were carried out for rare earth ores with different fines.The results showed that the overall porosity of rare earth ores with different fine particle contents did not change much during the clear water leaching process,and the median pore size(0.05～1 μm)and large pore size(1～10 μm)increased;and the higher the fine particle content of rare earth ores,the lower the proportion of increase in median pore size and large pore size.During the leaching process of magnesium sulfate solution,the porosity of rare earth ore with each fine particle content showed the phenomenon of rising and then falling,and the larger pore size(1～30 μm)was transformed to smaller pore size(0～1 μm)in the early stage of leaching,and the smaller pore size was gradually transformed to larger pore size in the late stage of leaching;the higher the fine particle content of rare earth ore,the slower the rising and falling stage of porosity,and the higher the degree of transformation between larger and smaller pore size.the higher the degree of conversion.