从钕铁硼废料中提取稀土工艺研究

采用氧化焙烧-盐酸分解法，研究从钕铁硼废料中提取稀土的工艺条件，探讨了焙烧温度和时间对铁的氧化率的影响，在浸出过程中考察了盐酸浓度、反应时间、反应温度以及液固比对稀土浸出率的影响，并分析了pH值和陈化时间对浸出液除杂效果的影响.结果表明:在700℃焙烧1.5 h，铁的氧化率最高，铁基本完全氧化成三价铁，在最佳浸出条件下稀土浸出率高达到99.33%，浸出液中和除杂时，调节pH值为3.5，陈化时间大于2 h，料液中非稀土杂质含量低，特别是铁仅为0.0014 g/L，浸出液完全达到稀土萃取的要求. 

Rare Earth recovery from NdFeB magnet scrap

The rare earth(RE) extraction conditions from Nd-Fe-B magnet scrap were studied by oxidation roasting -hydrochloric acid decomposition.The influence of calcination temperature and time on the iron oxidation rate was discussed in the roasting process. In the leaching process, the effects of hydrochloric acid concentration, reaction time, reaction temperature and liquid to solid ratio on leaching rate of rare earth were investigated too, and the influence of pH and the aging time of the impurity on the leaching liquid were analyzed. The results show that the oxidation rate of iron reaches maximum with calcining at 700 ℃ for 1.5 hours, and iron is completely oxidated to the trivalent iron. The RE leaching rate reaches 99.33% at the optimum conditions. After change the pH to 3.5 and the aging time to more than 2 hours for neutralization process, little impurities of Cu, Pb, Co and Fe are dissolved in the leaching solution. The Fe content in the leaching solution is only 0.0014 g/L, the rare earth leaching solution meets the requirements of RE extraction.