草酸沉淀反萃余液制备大粒度氧化钕工艺研究

Preparation of large particle neodymium oxide by oxalic acid precipitation with stripping solution

以草酸为沉淀剂,P507-N235-磺化煤油-环己烷体系分离稀土过程中的氯化钕反萃余液为原料,制备了大粒度氧化钕.采用激光粒度仪结合扫描电镜对样品进行粒度、形貌分析;使用X射线衍射对前驱体煅烧样品进行物相分析,结合差热分析研究前驱体的热分解过程.沉淀过程中草酸钕前驱体粒度的主要影响因素为反应温度、搅拌速度、沉淀剂滴加速度及陈化时间,其最佳制备条件为反应温度50℃,搅拌速度300r/min,沉淀剂滴加速度9mL/min,陈化时间24h.对比实验表明,氯化钕反萃余液中残余的有机相可以有效地增大前驱体的粒度.草酸钕前驱体在煅烧温度800℃下保温2h可完全转化为Nd2O3,氧化钕粒径达到50μm以上.

The large particle neodymium oxide is prepared with oxalic acid as precipitator, and stripping solution by P507-N235-kerosene-cyclohexane system as mother solution. The particle size, morphology,phase composition and thermal stability of samples are characterized by laser particle size analyzers, including SEM,XRD and TG-DTG. The main parameters affecting the particle size of precursor in precipitation are reaction temperature, stirring velocity, feeding speed and aging time. The optimum parameters are as follows： reaction temperature, 50 ℃; stirring velocity, 300r/min; feeding speed, 9mL/min; aging time, 24h. A comparative experiment indicates that the residual organic phase in stripping solution can effectively increase the particle size of precursor. Comparative experiments show that the residual organic phase stripping solution of neodymium oxide effectively increases the particle size of precursor. The precursor decomposes completely to neodymium oxide calcined at 800 ℃ for 2h. The median particle size of final neodymium oxide is larger than50μm.