离子间的相互作用对离子吸附型稀土浸出行为的影响

Effect of Ionic Interaction on Leaching Behavior of Ion-Adsorption Type Rare Earth Ore

为深化离子吸附型稀土矿浸取机制，从溶液化学的角度对稀土的浸出行为进行了研究。实验中采用不同浓度氯盐及硫酸盐（阳离子为：Na^＋，NH4^＋，Mg^2＋）作为浸取剂对高钇重稀土矿进行了静态浸取，并利用离子相互作用理论对浸出结果进行了分析。结果表明：低浓度时，浸取剂对稀土的浸出能力与其阳离子的吸附能力一致，SO4^2-较Cl^-对稀土表现出更强的配位助浸作用。反之，提升浸取剂浓度时，离子间逐渐增强的静电作用会抑制稀土的浸出，尤其对于高价态阳离子；此时SO4^2-对浸取阳离子的络合作用明显，生成的络合离子会对稀土的浸出造成屏蔽。因此，对稀土浸出行为特性的研究中有必要考虑到浸取剂本身的阴、阳离子特性。

To further research extraction mechanism, the extraction characteristic of rare earth elements from ion-adsorption type rare earth ore in different leaching conditions was studied from the aspect of solution chemistry. Here, NaCl, Na2SO4, NH4Cl, （ NH4 ）2SO4, MgCl2 and MgSO4 were adopted as leaching agents to extract rare earth from a heavy rare earth ore and this extraction was analyzed according to the Debye-Htickel ionic electrostatic interactions theory. The result showed that the order of rare earth extraction was mainly in accordance with their cation exchange capability when leaching agents were in low concentration; SO4^2- presented obvious coordination activation to rare earth extraction. With concentration of leaching agents increasing, the increased ionic interaction in leac- hing solutions could restrain rare earth extraction, especially to cations with high valence; the increased complexation between SO4^2- and cations could form a shielding to restrain the leaching process. So, the characteristic of cations and anions contained in the leac- hing agent should be considered to assess the behavior of rare earth elements during the leaching process.