Rare Earths Enrichment And Ammonium Removing From Low Concentration Of Rare Earths Solution

With the lack of resources and the improvement of environmental protection,it is significant to extract and enrich rare earths from low concentration of rare earths solution. Extract the diffcult leaching part of REs from ion adsorption rare earth ore is a important ways to improve the recovery rate. We need to use electrolyte solution(pH<4) to leach these part of REs,but the impurity ions of leaching solution will increase. The current technologys to enrich the REs are not useful. What’s more the residual REs and ammonium in tailings will be washed out by the rain,which has a serious impact on environment. Our rearch aims at the extraction and adsorption methods to enrich rare earth from leaching solution of ion adsorption rare earth and seepage waste water of tailings.We put forward two process to enrich and precipitate REs fron acidic leaching solution by N1923. The first process is precipitate part of impurities from leaching solution; Extract of REs with the extractant(20%N1923+10%2-octanol+10%kerosene);The extraction rate of REs is over 99%; The load of rare earth is about45g/L([m(RE2O3)/V(N1923)]);The raffinate contains some impurities(Al、Mg、Ca) can be used to leaching after adjusted it’s acidity and concentration.We determined the stripping conditions of REs with mixture solution, successfully recovered REs by precipitate the stripping solution. The supernatant can recycled to make stripping agent. Pretreatment slag can be used to protonate the extranctant after dissolved by H2SO4 or NH4HSO4, realize the recycling of extractant and rocover the REs in the slag. The second process is extract REs directly without pretreatment, the extractant after stripping contact with raffinate to realize the protonation and rocovering REs from raffinate, then the raffinate used to leach again. The results show that raffinate、organic phase and supernatant in the enrichment process all can be recycled.Compared with direct precipitation method, the purity of product increased 25% and the aluminium content decreased more than 80%.We determine a method which based on chlorination and adsorption to recycle REs and dispose ammonia nitrogen from seepage pour waste water at the same time.In the presence of clay, with charging N/Cl2=1:7~1:10, adjust the pH between10.5~11,aged above 30 min, after remove the residual chlorine, the solution can emissions in standard(NH4+-N<15ppm, pH=6~9). And the concentration of REs below 0.5 ppm, the recovery rate of rare earth is more than 95%.