Effects of Polyethyleneimine on Mass Transfer Process during Weathered Crust-Drenched Rare Earth Ore Leaching
Ammonium sulfate is the common leaching agent used for in-situ leaching of weathered crust elution-deposited rare earth ore,which is characterized by low mass transfer efficiency,high leaching agent consumption,and long leaching period.In order to solve the above problems,a surfactant material-polyethyleneimine(PEI)was compounded with 2.0％(mass fraction)ammonium sulfate to form a composite leaching agent,and the effects of flow rate of leaching agent,PEI concentration,temperature,and pH on the mass transfer processes of rare earths and aluminum during column leaching of weathered crust elution-deposited rare earth ore were investigated by applying the chromatographic plate theory.The results show that the mass transfer processes of the composite leaching agent for leaching rare earths and aluminum are in accordance with the Van Deemter equation,and the addition of PEI canstrengthen the mass transfer process of ammonium sulfate for rare earths and aluminum.With the increase of leaching solution temperature and pH,the theoretical plate numbers increase,the HETP decreases and the leaching mass transfer efficiency increasesfor the leaching of rare earths and aluminum.Considering that clay minerals have better pH buffering capacity,pH adjustment is not needed during the rare earth ore leaching operations.The optimal mass transfer conditions for leaching rare earths and aluminum with composite leaching agent are ammonium sulfate concentration of 2.0％(mass fraction),PEI concentration of 0.4％(mass fraction)and flow rate of 0.5 mL·min-1,and the mass transfer effects of rare earth leaching during summer operation can be enhanced.
weathered crust elution-deposited rare earth orepolyethyleneiminecomposite leaching agentleachingmass transfer
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维普
