从离子吸附型稀土浸出液到高浓度混合氯化稀土净化溶液  

From Leachate of Ion Adsorption Rare Earths to High Concentration of Rare Earth Chloride Purity Liquor

作　　者：胡秋雨 李艳阳 徐少东 胡晓倩 赵晴 王联建 刘艳珠[1] 周雪珍[1] 李东平[1] 李静[1] 李永绣[1] Hu Qiuyu;Li Yanyang;Xu Shaodong;Hu Xiaoqian;Zhao Qing;Wang Lianjian;Liu Yanzhu;Zhou Xuezhen;Li Dongping;Li Jing;Li Yongxiu(Institute of Rare Earths,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学稀土研究院,江西南昌330031

出　　处：《中国稀土学报》2022年第6期1045-1055,共11页Journal of the Chinese Society of Rare Earths

基　　金：国家重点研发计划项目(2019YFC0605000);国家自然科学基金项目(51864033,21978127);稀土资源利用国家重点实验室开放基金项目(RERU2019002)。

摘　　要：现行离子吸附型稀土氧化物或碳酸盐产品的质量问题突出,严重影响了后续萃取分离的效率和产品质量并产生较多的放射性废渣。本文对比研究了用石灰分别从氯化稀土和硫酸稀土溶液中沉淀稀土时沉淀率和所得产物的结晶性和质量,证明从硫酸稀土溶液中沉淀所得产物含有稀土碱式硫酸盐,煅烧氧化物的纯度只有80%~85%;而从氯化稀土溶液中沉淀稀土所获得产物为纯度更高,结晶性更好的氢氧化稀土,煅烧氧化物的纯度高于98%。提高沉淀温度,降低加料速度均有利于提高氢氧化稀土的结晶性和质量,而铝的存在会降低产物的结晶性和质量。据此,提出了以CaCl_(2)浸取离子吸附型稀土、用石灰沉淀富集和HCl溶解的方法生产无铵低铝低SO^(2-)_(4)高浓度氯化稀土料液的新技术,包括先全部沉淀再用HCl优溶和先预处理除铝再全部沉淀分离并用HCl直接溶解两种方法。所得高浓度氯化稀土料液的稀土浓度高于1mol·L^(-1),Al_(2)O_(3)含量低于30 mg·L^(-1),无检出NH_(4)^(+)和SO_(4)^(2-)离子。该技术应用不仅能够解决离子吸附型稀土矿山的氨氮污染和产品质量问题,而且对于高纯稀土分离过程的高效稳定化和清洁化具有非常重大的意义。The quality of ion adsorption rare earth(RE)concentrates is a serious problem which not only affects the extraction separation efficiency and product quality,but also produces more radioactive residues. In this paper,the precipitation rate,crystallinity and product quality of RE precipitated from their solutions of chloride and sulfate by lime were comparatively studied. The results show that the products precipitated from sulfate solution contain RE basic sulfate,the purity of the calcined oxide is only 80%~85%. However,RE(OH)_(3) with higher purity and better crystallinity can be obtained by lime precipitation method from its chloride solution,the purity of the calcined oxide is over 98%. Furthermore,the crystallinity and product quality of RE(OH)_(3) can be improved by increasing precipitation temperature and decreasing feeding speed,and be lowered by the coexisting of aluminum(Al). Therefore,a novel technology,which consists of leaching RE with calcium chloride,precipitating RE with lime and dissolving RE with hydrochloric acid,is proposed to produce REClsolution with high purity and high concentration. The process includes two basic methods:one is fully precipitating RE and Al first and then preferential dissolving RE with hydrochloride acid by controlling the pH at 4.0~4.5;another is precipitating RE and Al in stages by controlling the pH at 6 and then dissolving RE(OH)_(3) with hydrochloride acid.The analysis results show that the concentrations of RE and Al in the obtained RECl_(3) solution are over 1 mol·L^(-1)and less 30 mg·L^(-1)respectively,no ammonium and sulfate are detected. The precipitation rate of RE in leachate and the recovering rate of RE from the slag after RE preferential dissolved reaches 99%. This technology is of great significance for the stabilization and cleanliness of separation process of rare earths.

关 键 词：离子吸附型稀土 浸出液 沉淀富集 氯化稀土 石灰 

分 类 号：TD955[矿业工程—选矿] O614.33[理学—无机化学]