Extraction of rare earth and cobalt from leach residue of Nd-Fe-B waste by reductive leaching with iron powder
Extraction of rare earth and cobalt from leach residue of Nd-Fe-B waste by reductive leaching with iron powder
复制标题
DOI：
10.1016/j.hydromet.2022.105942
复制
发表时间：
2022-07-30
期刊：
影响因子：
4.7
通讯作者：
Ye, Chunlin
中科院分区：
文献类型：
--
作者：
Du, Haojie;Wang, Dong;Ye, Chunlin
采用氧化焙烧-硫酸浸出法从钕铁硼（Nd-Fe-B）磁铁废弃物中回收稀土后，从剩余浸出渣中提取稀土和钴，稀土含量约为0.67% (w/w)，钴含量约为0.36%，具有重要的环境和经济意义。然而，从低品位矿物中提取有价值的元素仍然具有挑战性。本研究的目的是在低酸性条件下，通过添加铁作为还原剂，加速Nd-Fe-B废物（MWLR）浸出渣中稀土和钴的溶解，有利于破坏主相氧化铁。为优化MWLR在硫酸体系中的浸出工艺，考察了反应温度、反应时间、硫酸用量、料液比、还原剂添加时间和还原剂用量等因素对浸出工艺的影响。Fe、Co、Nd分别为87.9%、99.7%、99.4%、73.2%和87.9%。动力学结果表明，在加入还原剂Fe的情况下，浸出过程由内部扩散和表面化学反应共同控制，转变为表面化学反应控制。本研究提出并验证了一种从MWLR中提取低品位稀土和钴的方法，并探讨了还原浸出过程的机理。
After recovering rare earth from neodymium-iron-boron (Nd-Fe-B) magnet waste via oxidation roasting-hydrochloric acid leaching, extracting rare earths and cobalt from remaining leach residue, containing about 0.67% (w/w) RE and 0.36% Co, is environmentally and economically important. However, extracting valuable elements from low-grade minerals remains challenging. The purpose of this study is to accelerate the dissolution of rare earths and cobalt from leach residue of Nd-Fe-B waste (MWLR) under low acidity by adding iron as a reductant, which is conducive to destroying the main phase iron oxide. To optimize the leaching process of MWLR in a sulfuric acid system, the effects of reaction temperature, reaction time, sulfuric acid dosage, solid/liquid (S/L) ratio, reductant addition time and reductant dosage were investigated. Circa 87.9% Fe, 99.7% Co, 99.4% Nd, 73.2% Pr and 87.9% Ce were leached. Furthermore, kinetic results indicated that the leaching process, controlled by a combination of internal diffusion and surface chemical reaction, changed to a surface chemical reaction control in the presence of Fe added as the reductant. This research proposed and verified a way to extract low-grade rare earths and cobalt from MWLR, and investigated the mechanism of reductive leaching process.