Extraction of rare earth elements from upgraded phosphate flotation tailings
Extraction of rare earth elements from upgraded phosphate flotation tailings
复制标题
DOI：
10.19150/mmp.6464
复制
发表时间：
2016-02
影响因子：
--
通讯作者：
S. Al-Thyabat;P. Zhang
中科院分区：
文献类型：
--
作者：
S. Al-Thyabat;P. Zhang
磷酸盐岩含有微量稀土元素（RE），并且可以作为这些关键材料的二次来源，因为每年开采大量的磷酸盐岩。人们的注意力主要集中在从磷石膏中提取稀土，磷石膏中含有超过70%的磷酸盐精矿中的稀土，而从砂尾矿和泥中提取稀土的工作很少，尽管它们分别占磷酸盐基质中稀土的16%和15%。采用重选和泡沫浮选两种方法对磷浮选尾矿进行提质处理。使用实验室摇床进行重力分离，而在Denver D-12浮选槽中进行浮选。经硝酸浸出、溶剂萃取和离子交换树脂萃取稀土元素后，尾矿中磷酸盐（P2 O 5）含量为2.6%，稀土元素含量为198.1 μg/g。结果发现，摇床可以产生尾矿精矿，测定为8.6%P2O5和616 µg/g稀土元素，但只有20%的稀土回收率，而泡沫浮选产生泡沫精矿，测定为8.1%P2O5和368.2 µg/g稀土元素，稀土回收率为63.5%。用5.2 M（25%）硝酸浸出浮选精矿，然后用溶剂和离子交换树脂萃取，得到的沉淀物中稀土含量分别为0.926和0.314%，相比之下，0.716和0.213%时，表精矿使用。
Phosphate rock contains traces of rare earth elements (REEs) and can be a secondary source of these critical materials as large tonnages of phosphate rock are mined annually. Attention has mostly focused on the extraction of REEs from phosphogypsum, which contains more than 70 percent of the REEs reporting to phosphate concentrate, with only limited work conducted on REE extraction from sand tailings and slime even though they account for 16 percent and 15 percent, respectively, of REEs mined with phosphate matrix.In this work, phosphate flotation tailings were upgraded by gravity separation and froth flotation. Gravity separation was conducted using a laboratory shaking table, while flotation was conducted in a Denver D-12 flotation cell. The concentrated tailings were then leached by nitric acid followed by REE extraction with solvent and ion-exchange resin.The sand tailings were assayed as having 2.6 percent phosphate (P2O5) and 198.1 µg/g REEs. It was found that the shaking table could produce tailing concentrate assayed as having 8.6 percent P2O5 and 616 µg/g REEs but with only 20 percent REE recovery, while the froth flotation produced froth concentrate assayed as having 8.1 percent P2O5 and 368.2 µg/g REEs with 63.5 percent REE recovery. Leaching the flotation concentrate with 5.2 M (25 percent) nitric acid followed by extraction with solvent and ion-exchange resin yielded precipitates with REE contents of 0.926 and 0.314 percent, respectively, compared with 0.716 and 0.213 percent when table concentrate was used.