氟碳铈矿焙烧过程中脱氟机制的研究

Defluorination Mechanism in Bastnaesite Calcining Process

测定了La F3和La OF在饱和水蒸气气氛下1000℃焙烧3 h后的脱氟率,采用X射线衍射技术对焙烧产物进行了物相分析。测定了氟碳铈矿在饱和水蒸气气氛下700~1000℃焙烧3 h后的焙烧产物中的氟含量,并对焙烧产物进行了物相分析,对焙烧前后的氟碳铈矿进行了SEM扫描对比分析。结果表明：氟碳铈矿发生脱氟反应的过程为：REF3·RE2（CO3）3首先分解生成REF3和RE2O3,同时伴随REOF的生成,然后在有水分子的条件下,REF3,REOF相继发生脱氟反应生成RE2O3和HF。

LaF3 , LaOF and the samples of bastnaesite were calcined in saturated steam for 3 h at 700 - 1000 ℃ The defluorination rates of their products were determined and the phases of calcined products of LaF3 , LaOF and bastnaesite were analyzed by X-ray diffraction （XRD）. The scanning electron microscopy （SEM） was used for an- alyzing the change of morphology of bastnaesite before and after calcination. The research results showed that the process of defluorination of bastnaesite can be simply described as follow ： firstly, at high temperature, REF3·RE2 （ CO3 ） 3 decomposes into REF3 and RE203 , and generates REOF at the same time. Then, the defluorination reac- tion of REF3 and REOF happens one after another under the condition of enough water molecule around them.