Experimental Study On Permeability Change Rule Of Ion-absorbed Rare-earth In Ore Leaching Process

The permeability of ionic rare earth ore had a significant impact on leaching process andchanged in slope stability caused by leaching. Therefore, this paper based on darcy’s law startedfrom the aspects of electric double layer theory, at the same time, it used the indoor columnleaching constant head tests to study variation of rare earth ion permeability in percolation process.By comparing the ion-absorbed rare-earth ore and screening sample particle size range of0.075~0.09mm, this paper explored the mechanism of permeability variation in leaching. Theconclusions included:(1) Through the water penetration test in rare earth ore sample, studying the effect of microparticle migration of permeability. The study found that micro-particles migration increased theseepage stability time and the range of seepage. With the hydraulic gradient increased, the seepagefield stable time decreased and flow range ability increased. Migration of the micro particle sizeranged in roughly0~29.3μm, the upper soil particles migration distance was short, it formed microparticle concentration area in its section, micro particles of the lower soil under the action ofdynamic water pressure out of the bottom of the sample, micro particle migration migrated notobvious in central soil.(2) Through the ammonium sulfate solution prismatic leaching test in rare earth ore sample,studying the effect of ion adsorption and ion exchange reaction of permeability. The study foundthat the ion adsorption and the ion exchange reduced the permeability coefficient, micro-particlesmigrate made the permeability coefficient increase or decrease, two opposite effect existed. Whenthe hydraulic gradient is less than a critical value, Ion adsorption and ion exchange is the mainreason made permeability coefficient change. When the hydraulic gradient is more than a criticalvalue，micro-particles migration is the main reason made permeability coefficient change. theimpact of micro-particles migration on permeability coefficient increased with increasing ofhydraulic gradient. As ore’s particle size distribution was more dispersed and graded well, theseepage filed of ore had longer stable time than screening sample.