聚乙二醇对风化壳淋积型稀土矿浸出的影响

Effects of Polyethylene Glycol on Leaching of Weathering Crust Elution-Deposited Rare Earth Ores

针对氯化铵作为浸取剂浸取风化壳淋积型稀土时,稀土浸取速率较低和浸出周期长等问题,使用聚乙二醇(PEG)为添加剂,通过柱浸试验模拟工业生产中的原地浸出工艺,探究不同聚合度的聚乙二醇对稀土矿渗透性和稀土浸出的影响。结果表明,聚乙二醇400、聚乙二醇1000和聚乙二醇4000溶液在稀土浸出过程中表现出较好的渗透效果。采用质量分数2.00%的聚乙二醇400、聚乙二醇1000、聚乙二醇4000分别与0.20mol/L的氯化铵复配,复配浸取剂溶液在稀土矿样中的渗透速率随着水力梯度的增大呈线性增大,符合达西定律。PEG400+NH4Cl、PEG1000+NH4Cl、PEG4000+NH4Cl以及NH4Cl溶液的稀土浸出率分别为82.61%、89.12%、70.67%和88.06%,且当聚乙二醇1000作为助浸剂时,渗流速率最大,渗透效果最佳。添加了聚乙二醇1000的复配浸取剂溶液,在浸取风化壳淋积型稀土矿中稀土的反应过程符合内扩散动力学模型。研究结果对提升复配浸取剂溶液在稀土矿体中的渗流速率有重要意义。

In order to improve low leaching rate and reduce long leaching period of weathering crust elution-deposited rare earth ore with ammonium chloride as leaching agent,effects of polyethylene glycol with different degree of polymerization on permeability and leaching of rare earth ore were investigated by column leaching experiments.The results show that PEG400,PEG1000 and PEG4000 have good permeability during rare earth leaching.By mixing mass fraction of 2.00%PEG400,PEG1000,PEG4000and ammonium chloride solution of 0.20 mol/L,respectively,it is found that their permeation rates in rare earth samples rise linearly with increase of hydraulic gradient according with Darcy’s law.Leaching rate of rare earth with PEG400+NH4Cl,PEG1000+NH4Cl,PEG4000+NH4Cl and NH4Cl solution is82.61%,89.12%,70.67%and 88.06%,respectively.When polyethylene glycol 1000is used as leaching aid,permeability is the biggest and permeation effect is the best.The process of adding PEG1000compound extractant solution leaching rare earths from weathering crust elution-deposited rare earth ore meets with shrinking-core dynamical model.This study is of practical significance to improve leaching efficiency of rare earth in practical production.