稀土精矿焙烧过程中氯化铝对氟逸出的影响

Effect of Aluminum Chloride on Fluorine Escape during Roasting of Rare Earth Concentrate

对白云鄂博稀土精矿焙烧过程中氯化铝对氟逸出的影响进行了深入研究,焙烧过程加入氯化铝实现了较好的固氟效果。首先利用同步热分析仪分析了白云鄂博稀土精矿、氯化铝和稀土精矿-氯化铝混合物的热分解过程中的质量变化和热效应的变化,白云鄂博稀土精矿与结晶氯化铝混合物热分解反应发生在100~508℃;其次,分别研究了焙烧温度、矿铝比和焙烧时间对固氟效率的影响,在矿铝比1∶1、焙烧温度510℃、焙烧时间2 h时,固氟效率达到66.9%,稀土精矿焙烧过程中氟的逸出率由22.71%降至7.51%;最后,采用X衍射射线分析仪分别对白云鄂博稀土精矿、稀土精矿的焙烧产物、稀土精矿与氯化铝的混合焙烧产物进行了物相分析,精矿中的氟以AlF_(3)形式固存在焙烧产物中。

Effect of aluminum chloride on fluorine escape during roasting of Bayan Obo rare earth concentrate was deeply studied.The addition of aluminum chloride during roasting achieved a good fluorine fixation effect.Firstly,changes of weight and thermal effect during thermal decomposition of rare earth concentrate,aluminum chloride and rare earth concentrate aluminum chloride mixture were analyzed by synchronous thermal analyzer.Thermal decomposition reaction of rare earth concentrate and crystalline aluminum chloride mixture occurs at 100-508℃.Secondly,effects of roasting temperature,ratio of ore to aluminum,and roasting time on fluorine fixation efficiency were studied.The results show that fluorine fixation efficiency is 66.9% and escape of fluorine drops from 22.71% to 7.51% under the conditions including ratio of ore to aluminum of 1∶1,roasting temperature of 510℃,and roasting time of 2 h.Finally,phase analysis of rare earth concentrate,roasting products of rare earth concentrate and mixed roasting products of rare earth concentrate and aluminum chloride were carried out by X-ray diffraction analyzer,the results show that fluorine in concentrate is fixed in roasting products in form of AlF_(3).