Abstract: As we know that the zirconium and hafnium elements have similar physical and chemical properties with the scandium, this is one of main reasons for a low purity of scandium oxide because it is difficult to separate them. In order to solve this problem, an ammonium o-iodobenzoate was used as a precipitant to remove the zirconium and hafnium impurities in scandium oxide. Different experimental parameters were optimized systematically enabling the best condition. To further verify and improve the process conditions, large scale production experiments using the industrial devices were also studied based on the laboratory result. The optimized treatment conditions were obtained when the acidity of the solution was 0.1mol/L, the amount of the precipitant was 1.1 times of the theoretical value, and the temperature was 100℃ during stirring for 30min. To recover the ammonium o-iodobenzoate, ammonia solution was used to deal with the zirconium and hafnium deposit. The FTIR、SEM and HPLC results indicated that zirconium and hafnium elements have been transformed into hydroxide precipitation and the ammonium o-iodobenzoate was recovered. The recoveries of scandium and ammonium o-iodobenzoate in industrial experiments were 99.54% and 95.19%, respectively. The removal ratio for both zirconium and hafnium was 99.6%.

Key words: ammonium o-iodobenzoate, separation, precipitation, reaction, scandium, zirconium, hafnium

摘要： 锆、铪与钪物理化学性质相似且难以分离，是导致氧化钪纯度不高的主要原因之一。为解决这一问题，本文采用邻碘苯甲酸铵作为沉淀剂，去除粗氧化钪中的锆、铪杂质，通过优化不同实验参数得到最佳工艺条件。在实验研发基础上本工艺进行工业生产，进一步验证及完善了工艺条件。得出在溶液酸度为0.1mol/L、沉淀剂加入量为理论量的1.1倍、100℃保温条件下搅拌30min时处理效果最佳。利用氨水与锆、铪沉淀反应回收沉淀剂，通过FTIR和SEM对锆和铪原沉淀与现沉淀进行表征，高效液相色谱对滤液进行分析，结果表明原沉淀物反应生成氢氧化物和邻碘苯甲酸铵。工业实验中钪和邻碘苯甲酸铵回收率分别为99.54%和95.19%，锆、铪去除率均为99.6%。

关键词: 邻碘苯甲酸铵, 分离, 沉淀, 反应, 钪, 锆, 铪