四川稀土矿尾砂的稀土元素和微量元素地球化学特征及开发利用意义

Geochemistry of Rare Earth and Trace Elements in Rare Earth Tailings from Sichuan Province and the Significance of the Exploitation and Utilization

四川是我国轻稀土的重要产地,稀土开采至今已有二十多年的历史,积存了大量尾砂。尾砂中仍然有丰富的稀土资源,但这部分资源究竟有多大的量、能不能再次回收,如何回收,则是当务之急。为查明稀土尾砂中各类元素的分布特征,本文对A、B、C、D四个稀土矿山的尾砂开展了稀土元素和微量元素地球化学特征的初步研究。结果表明:尾砂中稀土元素配分特征继承了原矿石,稀土氧化物含量普遍偏高(0.78%～2.12%),均超过了现行工业指标的边界品位(0.5%～1.0%),且老尾砂的稀土含量高于新尾砂;除了富集稀土元素之外,A矿区尾砂中Ba含量可达1.8%,B矿区尾砂中Sr含量超过10%,C矿区尾砂中Sr含量为2.7%。同时,不同矿区的尾砂中Mo、Bi、Pb、Ag等有用元素发生了不同程度地富集(值得综合回收利用),尤其是Mo达到了边界品位(磁选后的尾砂Mo含量达到2.275%)。本文提出,今后不仅要加强保护四川稀土尾砂,而且需对富集的有用元素采取恰当的方式加以综合回收。

Sichuan Province is one of the most important provinces in China for light rare earth element（LREE） resources,where they have been mined for more than 20 years.There is now a large volume of tailings present in the mines still containing an abundance of rare earth resources.It would be beneficial to the mine owners to recover the REEs in the tailings so an estimate of the amount would be extremely beneficial.Preliminary research has already been undertaken on the geochemistry of trace and rare earth elements in tailing samples from the A,B,C and D REE deposits.The results show that the REE distribution patterns of tailing samples are inherited from rare earth ores in REE deposits.The contents of rare earth oxides（REO） in samples are higher than the current cut-off grade（0.5%-1.0%）,and the old tailings are higher than the new.In addition to the enrichment of REEs, samples of B（Sr 10%） and C（Sr 2.7%） are also rich in Sr while A samples are rich in Ba（1.8%）.Mo,Bi, Pb and Ag are enriched in different degrees in all samples and in particular,the Mo content reached its cut-off grade,at 2.275% in the tailings of magnetic separation.It is evident from these results that it is necessary to protect tailings in rare earth mines in Sichuan Province,and to take appropriate measures to reclaim higher concentration elements.