稀土冶炼副产品中提取铈的工艺研究

The Technical Study on Cerium Extraction from the By-products of Rare Earths Refinery

某矿生产工艺采用两步盐酸优溶法生产少铈富镧混合氯化稀土,同时产生大量的铈富集物中间产品。这种粗铈产品提纯困难,价格低廉,用途单一,只能用来生产稀土硅铁合金。采用硫酸溶解铈富集物,溶解完全后加入还原剂——硫脲,四价铈还原成三价铈,使混合稀土全部为三价稀土。用MgO中和除渣后用P204-煤油萃取全捞稀土,盐酸反萃取,提取出混合氯化稀土。

Two-step hydrochloric acid preferential dissolution method is adopted in rare earth ore production in Mianning,Sichuan,in order to produce the mixed rare earth oxide with less cerium but rich lanthanum,as well as the by-product that large amount of cerium concentrates. It is difficult to purify this kind of crude cerium product,which has low price,single purpose,only can be used to produce rare earth ferro-silicon alloy. Cerium concentration is dissolved by sulfuric acid,and then added the reducing agent-thiourea,therefore,the tetravalent cerium is reduced to tervalent cerium,so the mixed rare earth are all tervalent rare earth. The rare earth is extracted byP204 kerosene after MgO neutralization and residues removal,using hydrochloric acid for reextraction,so the mixed rare earth oxide can beexacted.