Research On The Permeability Characteristics Of Ion-type Rare Earth Ore And Its Influence On Leaching

Ion-absorbed rare earth ores are rich in medium and heavy rare earth elements and are of great strategic value.At present,ion-absorbed rare earth ores are mainly mined by in-situ leaching technology,which is essentially the process of seepage and ion exchange of leaching agent in ore bodies.It is an important prerequisite for the efficient exploitation and utilization of ion-absorbed rare earth ores to master their permeation characteristics.At present,some ion-absorbed rare earth minerals in China are difficult to infiltrate and leach,which to some extent restricts the efficient exploitation and utilization of rare earth resources.In view of the characteristics of a certain type of ionic rare earth ore difficult to infiltrate and leach,this paper studies the change rule of the permeability of this type of ionic rare earth ore by means of constant head infiltration experiment,particle size analysis,Zeta potential analysis and scanning electron microscopy,and investigates the influence of permeability on rare earth leaching through column leaching experiment.The main research results are as follows:(1)The saturation and permeability test of water in the ion-absorbed rare earth ore was carried out to investigate the influence of ore body porosity struct and permeability head on its permeability.The results show that the migration of fine particles(< 10um)in ion-absorbed rare earth ore occurs during the permeation process,and the pore ratio of ore body and permeation head will affect the degree of migration,thus affecting the permeability of ore sample.When the pore ratio of the ore sample is 1.2 and the infiltration head is large,the particles migrate from the upper middle layer to the middle and lower layers.The permeability coefficient of the upper layer increases and the middle and lower layers decreases,the permeability coefficient of the lower layers is the minimum.When the infiltration water head is small,the particle migration distance is short,and the permeability coefficient of each layer decreases.The permeability coefficient in the upper layer > in the lower layer > in the middle layer.When the porosity ratio is 1.0,the permeability coefficients of the upper,middle and lower layers all decrease under different permeability heads.The permeability coefficient in the upper layer > in the lower layer > in the middle layer.(2)On the basis of water saturation of the ion-absorbed rare earth ore,saturation permeability tests of three leaching agents were carried out to investigate the influence of concentration and type of leaching agent on rare earth ore permeability.The results show that the higher the leaching agent concentration is,the higher the solution viscosity is,and the lower the seepage flow on ion-absorbed rare earth ore is.And at the same concentration,solution viscosity: magnesium sulfate > calcium chloride > ammonium sulfate.Due to the influence of chemical action,the infiltration of three leaching agents has different effects on the migration of particles in ion-absorbed rare earth ores.Magnesium sulfate and calcium chloride can make the mineral electric double layer strongly compression,micro particle migration was depressed,in the process of their penetration,seepage flow can maintain stability after falling fast,but with ammonium sulfate infiltration,seepage flow was continues to decline,infiltration after 56 h,permeability: calcium chloride>magnesium sulfate > ammonium sulfate.(3)The column leaching process optimization test of two ion-absorbed rare earth minerals with pore ratios of 1.2 and 1.0 was carried out.The results show that decreasing the flow rate,increasing the concentration of leaching agent and increasing the amount of wash water can improving the leaching effect of refractory rare earth ores.Under the respective optimal conditions,the rare earth leaching rates of the two kinds of pore ratios were 94.24% and 92.16%,respectively,and the rare earth concentrations of the leaching solution were 488.69mg/L and 545.45mg/L,respectively.The research results can lay a theoretical foundation for optimizing in-situ ion leaching process and promoting safe and efficient exploitation and utilization of rare earth resources.