Magnetic properties of REE fluorcarbonate minerals and their implications for minerals processing
Magnetic properties of REE fluorcarbonate minerals and their implications for minerals processing
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DOI：
10.1016/j.mineng.2018.11.042
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发表时间：
2019-01
影响因子：
4.8
通讯作者：
S. Al-Ali;F. Wall;R. Sheridan;J. Pickles;Richard Pascoe
中科院分区：
文献类型：
--
作者：
S. Al-Ali;F. Wall;R. Sheridan;J. Pickles;Richard Pascoe
稀土元素被认为是电子和绿色技术的关键金属。稀土氟碳酸盐是稀土矿的主要矿物之一，常见于许多不同类型的稀土存款中，但其一些基本性质至今尚未确定。采用振动样品磁力仪（VSM）测量了纯稀土氟碳酸盐单晶矿物的磁性，并采用电子探针微量分析（EPMA）确定了其元素组成。这些结果提供了除氟碳铈矿外的稀土氟碳酸盐的磁性和磁化率的首次测量。稀土氟碳酸盐的磁化率在不同矿物之间有系统的变化，并高度依赖于矿物化学性质。它对氟碳铈矿-（Ce）是正的（顺磁性），并随着钙含量的增加而逐渐减少，对该系列中富含钙的成员--伦琴矿（röntgenite）则是负的（反磁性）。同步石-（Ce）难以测量、产生良好的信号并获得准确的读数，因为它实际上总是以<5 mg晶体的形式出现。通过对某稀土矿存款样品的磁化率测定和SQUID磁力仪的相关研究，发现该稀土矿具有反磁性矿物的特征，其原因除稀土氟碳酸盐系列矿物层状结构的变化外，还与Ca含量的增加和REE含量的降低有关。鉴于稀土氟碳酸盐的磁化率范围很广，在制定选矿流程图之前仔细确定矿物学是很重要的。
Rare earth elements (REE) are considered as critical metals for electronics and green technology. The REE fluorcarbonates are one of the main REE ore minerals, common in many different types of REE deposit and yet some of their fundamental properties have still not been determined. This study measured the magnetic properties of pure REE fluorcarbonate single crystal minerals using a vibrating sample magnetometer (VSM) and determined their elemental compositions using electron probe microanalysis (EPMA). The results provide the first measurements of the magnetic behaviour and susceptibility of REE fluorcarbonates other than bastnäsite-(Ce). The magnetic susceptibility of REE fluorcarbonates varies systematically from one mineral to another and is highly dependent on the mineral chemistry. It is positive (paramagnetic) for bastnäsite-(Ce) and gradually decreases as the amount of Ca increases in parisite-(Ce), becoming negative (diamagnetic) for the Ca-rich member of the series, röntgenite. Synchysite-(Ce) is difficult to measure, generate good signal and acquire accurate readings because it practically always occurs as <5 mg crystals. Its magnetic susceptibility in samples from a REE ore deposit was experimentally determined by magnetic separation and checked by an associated study using a SQUID magnetometer, synchysite-(Ce) behaved as a diamagnetic mineral. This can be explained by the increase of Ca content and decrease of REE content, in addition to the variations in the layered structure common to the REE fluorcarbonate series minerals. Given the wide range of magnetic susceptibility of REE fluorcarbonates, it is important that the mineralogy is determined carefully before setting up a mineral processing flow sheet.