离子型稀土矿浸出过程微细颗粒迁移规律及调控

Migration Law and Regulation of Fine Particles during Leaching of Ion-adsorption-type Rare Earth Ore

离子型稀土矿在浸出过程中浸出剂与矿石表面水合机制较为复杂,颗粒间的桥式胶结因离子吸附交换过程中存在多种作用力与分散作用而容易发生断裂,从而使微细颗粒发生迁移和重新排列,并在孔喉处沉淀,产生堵塞现象,影响离子型稀土的浸出效率。为揭示离子型稀土矿在原地浸出过程中微细颗粒的迁移规律,并找到适宜的调控方法,以龙南足洞离子型稀土矿为研究对象,采用实验室柱式溶浸法,考察了浸出剂质量浓度、黏度、流速、水力梯度、矿体高度及矿体含水率对微细颗粒迁移的影响。结果表明,离子型稀土矿浸出过程微细颗粒的迁移是影响浸出效率的重要因素之一。在外力的作用下,微细颗粒在浸出过程中易随浸出剂发生迁移运动。当调控浸出剂质量浓度低于4%,浸出剂黏度不超过1.5 mPa·s,水力梯度小于0.75,浸出剂流速低于3 mL/min,原矿含水量大于11%时,矿体中微细颗粒迁移率较低,矿体渗透性保持良好,有利于浸出液的渗流和稀土离子的浸取。

The hydration mechanism between leaching agent and ore surface is complex during leaching of ion-adsorption-type rare earth ore.The bridge cementation between particles is easy to fracture due to variety forces and dispersion during ion adsorption and exchange,so that the fine particles migrate and rearrange,and precipitate at the pore throat to produce blockage.It affects leaching efficiency of ion-adsorption-type rare earth.In order to reveal the migration law of fine particles during in-situ leaching of ion-adsorption-type rare earth ore and find appropriate control methods,typical ion-adsorption-type rare earth ore in Longnan was taken as the research object to investigate effects of leaching agent concentration,viscosity,flow velocity,hydraulic gradient,ore body height and ore body moisture content on migration of fine particles by laboratory column leaching method.The results show that migration of fine particles in ionic rare earth ore is one of the important factors affecting leaching efficiency.Under the action of external force,fine particles are easy to migrate with leaching agent during leaching.When mass concentration of leaching agent is<4%,viscosity of leaching agent is<1.5 mPa·s,hydraulic gradient is<0.75,flow rate of leaching agent is<3 mL/min,and the water content of raw ore is>11%,the mobility of fine particles in ore is low and the permeability of ore body is good.This is conducive to the seepage of leaching solution and leaching of rare earth ion.