机械研磨对离子吸附型稀土矿石中稀土赋存形态的影响

Effect of Mechanical Grinding Process on the Morphology of Rare Earth Elements in Ion-adsorbed Rare Earth Ores

离子吸附型稀土矿是一类稀土元素呈水合或水合羟基吸附在黏土矿物表面的风化矿床。首次发现了这类矿石中在干法研磨条件下会导致稀土相态发生变化,通过模拟实验,证实机械研磨对矿石中离子相稀土含量变化的影响及其相态转变路径。结果表明,研磨后矿石中减少的离子相稀土主要转换为碳酸盐结合态,少数转换为铁锰结合态、腐殖酸结合态。其中,离子交换稀土减少53.48%,而碳酸盐结合态稀土增加36.05%。XRD和FTIR表明,机械研磨过程会导致黏土矿物发生结构性损伤,晶体结构受到变形,引起黏土矿物晶格破坏,出现了无序化特征。机械研磨伴随发生的机械力化学过程,可能是导致机械研磨后离子相稀土减少、稀土赋存状态变化、形态间发生转移等变化的关键原因,对于制定离子吸附型稀土矿勘查规范、矿石加工工艺、标准物质的研制流程、分析测试及黏土矿物的机械研磨机理研究等领域都具有重要的启示意义。机械研磨离子吸附型稀土矿矿石导致离子相稀土减少是这类矿床研究中一个重要的新发现。

Ion adsorption type rare earth ores(IAREO)are a type of weathered ore deposit where rare earth elements are adsorbed on the surface of clay minerals in the form of hydrated or hydrated hydroxyl groups.This study found for the first time that dry grinding conditions for this type of ore can cause changes in the rare earth phase state.Through simulation experiments,it was confirmed that mechanical grinding has an impact on the changes in the ion phase rare earth content in the ore and its phase transition path.The results showed that the reduced Ion-exchangeable(F2)in the ore after grinding are mainly converted into Carbonate-bound(F3),and a few are converted into Fe-Mn oxide-bound(F5)and Humic bound(F4).Among them,F2 decreased by 53.48%,while F3 increased by 36.05%.The evidence from XRD and FTIR indicates that the mechanical grinding process can cause structural damage to clay minerals,and the crystal structure is deformed,causing the lattice damage of clay minerals and the appearance of disordered features.The occurrence of mechanochemical processes accompanying mechanical grinding may be the key reason for the reduction of ion phase rare earths,changes in rare earth occurrence state,and transfer between forms after mechanical grinding;It has important implications for the development of exploration specifications for ion adsorption type rare earth minerals,ore processing technology,development process of standard materials,analysis and testing,and research on mechanical grinding mechanisms of clay mineral.The reduction of ion phase rare earths caused by mechanical grinding of ion adsorption type rare earth ores is an important new discovery in the deposits.