摘要
对碳酸氢铵沉淀钇时碳酸钇铵复盐结晶的形成条件与pH变化特征进行了研究 ,发现其结晶过程与平衡溶液pH有对应关系。溶液pH由碳酸钇铵结晶化反应和碳酸氢铵的水解反应所控制。根据溶液pH的变化可以判断结晶反应是否发生或完成 ,以及结晶速度的快慢和结晶的程度。X -射线衍射及差热 -热重分析结果表明 ,产物为复盐结晶 ,加料比与加料方式对结晶的形成有很大影响。
The research was mainly based on the formation condition of crystalline ammonium yttrium carbonate and the variation characteristics of pH value during the crystallization in which NH 4HCO 3 was used to precipitate yttrium ion It is found that the crystallization process is always associated with the descent of pH The pH of solution is controlled by the crystallization reaction of ammonium yttrium carbonate and the hydrolysis of NH 4HCO 3 Based on the pH variation, it can be judged whether the crystallization reaction occurs or not and the speed and the degree of crystallinity can be determined The precipitates were characterized by X-ray powder diffraction and differential thermal-thermogravimetric analysis The results show that the crystallization is the process of NH 4Y(CO 3) 2 formation and it is effected by feed ratio and feed method
出处
《中国稀土学报》
CAS
CSCD
北大核心
2000年第1期79-81,共3页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金! ( 597640 0 1 )
江西省自然科学基金!资助项目
关键词
碳酸钇铵
结晶过程
稀土元素
rare earths
ammonium yttrium carbonate
crystallization
