氟化钠提纯工艺研究  

Study on purification process of sodium fluoride

作　　者：李帅[1] 李天祥[1] 朱静[1] 刘松林 LI Shuai;LI Tianxiang;ZHU Jing;LIU Songlin(School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China;State Key Laboratoryof Efficient Utilization for Low Grade Phosphate Rock and Its Associated Resources,Guiyang 550014,China)

机构地区：[1]贵州大学化学与化工学院,贵州贵阳550025 [2]中低品位磷矿及其共伴生资源高效利用国家重点实验室,贵州贵阳550014

出　　处：《无机盐工业》2024年第9期90-97,共8页Inorganic Chemicals Industry

摘　　要：经过处理后的氟化钠原料中含有较多的硅酸钠杂质。为了去除其中的杂质,提高氟化钠的纯度,获得更高的工业价值。利用溶出硅胶与蒸发结晶操作过程相结合,设计了溶出硅胶-蒸发结晶提纯氟化钠工艺,提高了氟化钠的纯度,降低了硅的含量,并且改善了氟化钠产品的外观。在溶出硅胶实验中,考察了硫酸用量比、温度、时间、搅拌速率对脱硅过程的影响,并进行了正交试验。结果表明,在溶出硅胶实验中,综合效果最好的脱硅条件为硫酸的用量比(硫酸与氟化钠原料的质量比)为0.04、反应温度为25℃、反应时间为30 min、搅拌速率为300 r/min。在蒸发结晶实验中,当蒸发时间为60 min时,蒸发结晶提纯氟化钠的综合效果最好。在最佳的实验条件下,能得到纯度>98%,二氧化硅质量分数<0.5%的氟化钠产品。研究表明,硫酸与硅酸钠反应能溶出硅胶,再过滤分离能达到除硅的效果,而通过蒸发结晶,能进一步提高氟化钠的纯度。该研究可为提纯氟化钠、回收氟硅资源提供新思路。The treated sodium fluoride raw material contains many sodium silicate impurities.In order to remove the impurities in it,improve the purity of sodium fluoride and obtain higher industrial value,using silicon dioxide generation with evaporation crystallization,a process of sodium fluoride purification by silicon dioxide generationevaporation crystallization was designed to improve the purity of sodium fluoride,reduce the content of silicon,and improve the appearance of the sodium fluoride product.In the silicon dioxide generation experiment,the effects of sulfuric acid dosage ratio,temperature,time and stirring speed on the desilication process were investigated,and orthogonal experiments were carried out.The results showed that in the silicon dioxide generation experiment,the desilication conditions with the best overall performance were:sulfuric acid dosage ratio of 0.04,reaction temperature of 25℃,reaction time of 30 min,and stirring speed of 300 r/min.In the evaporation and crystallization experiment,the best overall performance of evaporation and crystallization for the purification of sodium fluoride was achieved when the evaporation time was 60 min.Under the optimal experimental conditions,a sodium fluoride product with a purity>98%and a silica mass fraction<0.5%could be obtained.The study showed that the reaction between sulfuric acid and sodium silicate could react to produce silica gel,and then filtration and separation could achieve the effect of silica removal,and the purity of sodium fluoride could be further improved by evaporation and crystallization.This study could provide new ideas for the purification of sodium fluoride and the recovery of fluorosilicon resources.

关 键 词：含氟硅渣 氟化钠提纯 脱硅 蒸发结晶 氟硅资源回收 

分 类 号：TQ124.3[化学工程—无机化工]