Experimental Investigation Of Leaching Intractable Ionic Rare Earth Ore By New Leaching Agent

With the extensive long-term development of rare earth resources, ionic rare earth oreseriously depleted, permeability variation of rare earth mine, in the leaching process, the rareearth smearing and adsorption serious, eventually leading to leaching agent consumed in largequantities, long period, and large quantity of the leachate, low concentrations of rare earth,high impurity content, lower recovery, seriously affecting the quality and resource utilizationof RE. In this study, the nature of the intractable ionic rare earth ore, the selection of theSelective, good permeability, efficient and environmentally friendly new leaching agent, onthe basis of improve the rare earth leaching rate and efficiency, reduce the impurity content,Improve the rare earth concentration, reduce the consumption of ammonium sulfate, tooptimize the leaching process, effectively improve the resource utilization of rare earth.On the basis of the nature of the intractable ionic rare earth ore, first determined theoptimal process parameters by exploring the test, followed by test the leaching agents toselect the best kind of leaching agent, then determined the best of the leaching process usethis kind of leaching agent, finally, the new rare earth ore leaching agent leaching mechanismwas discussed and researched.The optimal process parameters leaching by ammonium sulfate: column leaching,leaching agent concentration of2%, the flow rate was0.6mL/min, moisture content of7%,liquid-solid ratio is1:1, mineral density is loaded1.27kg/L(Natural loaded mine), rare earthleaching rate is88.62%, the rare earth ion content is0.73g/L, the aluminum ion content is0.085g/L.Leaching agent species results showed: compared with ammonium sulfate, whenQZX-01, QZX-02and compound leaching agent (ammonium chloride: ammoniumsulfate=7:3) as leaching agent, rare earth leaching rate increased7.53%,9.72%and4.17%.Aluminum ion concentration of reduce0.025g/L, reduce0.074g/L and increase0.028g/L.Magnesium sulfate as a leaching agent, although the aluminum ion concentration decreased,but the leaching rate of rare earth decrease28%, don’t conducive to comprehensive recoveryof rare earth. Other leaching agents leaching rare earth, the leaching rates are significantlylower. Be considered that QZX-01and QZX-02replace ammonium sulfate to leaching therare earth ore. But a larger impact on the environment of QZX-01, and QZX-02is a complexsalt of an organic acid, non-toxic, widely used in industry. Therefore, chose QZX-02as the rare earth ore leaching agent. The optimal process parameters: leaching agent concentration of2%, the ratio of QZX-02with ammonium sulfate is7:3, the flow rate is0.4mL/min,liquid-solid ratio is0.8:1, rare earth leaching rate is98.29%, the rare earth ion content is1.07g/L, the aluminum ion content is0.017g/L. Compared with the leaching by ammoniumsulfate, liquid-solid ratio decreased by20%, rare earth leaching rate increased by9.67%,aluminum ion concentration decreased by80%, there is a good leaching effect.The studies of leaching kinetics of the new leaching agent with intractable ionic rareearth ore showed: the process of the new leaching agent leaching of the rare earth orecontrolled by the internal diffusion, and the apparent activation energy of the reaction was8.59kJ/mol, compared with the7.34kJ/mol of ammonium sulfate system, higher efficiency ofthe process leaching with new leaching agent.