溶剂萃取法净化磷酸中氟的研究

以三辛胺(TOA)为萃取剂净化磷酸中的氟离子,考察了稀释剂、萃取剂浓度、萃取时间、温度对萃取的影响,并研究了磷酸中杂质离子的存在对脱氟性能的影响。结果表明,在萃取剂TOA浓度0.5 mol/L(稀释剂为磺化煤油),萃取时间20 min,温度303 K,转速200 r/min,相体积比(O/A)=1∶1的条件下,脱氟率可达70%以上。磷酸中Fe3+]=0.02～0.07 mol/L,Mg2+]=0.06～0.08 mol/L范围内,对萃取脱氟是有利的,铝离子和钙离子的存在均不利于氟、磷的分离。

Removal of fluoride from phosphoric acid using solvent extraction

The most suitable technological conditions have been studied in the extraction process of removal of fluoride from phosphoric acid,in which TOA was chosen as extractan.The influences on extraction process were investigated,which involved diluent,extractant concentration,extracting time,temperature and so on.Especially,the effect of impurities on the extraction ability was considered.The results indicated that the optimum conditions of extraction process include extractant concentration CTOA=0.5 mol/L(sulfonated kerosene as diluent),extracting time was 20 min,temperature was 303 K,stirring speed was 200 r/min,phase volume ratio(O/A) was 1 ∶1.The existence of calcium ion and aluminum ion was unfavorable to removal of fluoride from phosphoric acid.However,iron ion and magnesium ion benefit defluorination in the range of =0.02～0.07 mol/L or =0.06～0.08 mol/L.