首页|Leaching kinetics and permeability of polyethyleneimine added ammonium sulfate on weathered crust elution-deposited rare earth ores
Leaching kinetics and permeability of polyethyleneimine added ammonium sulfate on weathered crust elution-deposited rare earth ores
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At present,in-situ leaching of weathered crust elution-deposited rare earth ores(WCE-DREOs)encounter with problems such as long leaching cycles,slow infiltration rate and low product purity.In order to solve the above problems,the conventional leaching agent ammonium sulfate((NH4)2SO4)was com-pounded with polymeric surfactant polyethyleneimine(PEI)to form a composite leaching agent.The effects of leaching temperature,PEI concentration,flow rate and pH on leaching kinetics and perme-ability of rare earths(RE)and aluminum(Al)in orebody were studied.It is found that with temperature increasing,the time required to reach leaching equilibrium for both RE and Al is shortened,the apparent activation energies of RE and Al are 14.79 and 13.45 kJ/mol,respectively,and the leaching processes are in accordance with the outer diffusion control.When the concentrations of(NH4)2SO4 and PEI in the composite leaching agent are 2.0 wt％and 0.4 wt％,the time required to reach leaching equilibrium for RE and Al is about 50％shorter than that using(NH4)2SO4 alone,and the leaching efficiencies of RE are slightly higher than that of Al.Properly increasing the temperature and flow rate of the composite leaching agent can improve the leaching efficiencies of RE and Al,but pH has neglected effects on the leaching efficiencies of RE.At PEI concentrations below 0.4 wt％,the addition of PEI promotes the leaching of RE and Al.In column leaching studies of the WCE-DREO,the addition of 0.4 wt％PEI to the traditional leaching agent(NH4)2SO4 has no impact on the leaching efficiencies of RE.However,it can significantly increase the infiltration rate of WCE-DREO,shortening the leaching time per 10 mL effluent from about 30 min for(NH4)2SO4 leaching system to 20 min for the composite leaching system.The leaching time is shortened by one-third,and the leaching cost is reduced,which can provide theoretical guidance for the development and commercial implementation of novel composite leaching agent for WCE-DREO.
PolyethyleneimineKineticsRare earthsPermeabilityActivation energy
Huifang Yang、Aoyang Sha、Zhengyan He、Chenjie Wu、Yuanlai Xu、Jingjing Hu、Zhigao Xu、Ru'an Chi
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Key Laboratory for Green Chemical Process of Ministry of Education,School of Resources & Safety Engineering,Wuhan Institute of Technology,Wuhan 430073,China
Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission,College of Resources and Environmental Science,South-Central Minzu University,Wuhan 430074,China
National Natural Science Foundation of ChinaNational Key Research and Development Program of China
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