NaOH提纯粗品磷酸锂的工艺研究  

Study on Purification of Crude Lithium Phosphate with NaOH

作　　者：黄启行 余奔 李健 刘俊才 黄灵美 张仁国 贾义旺[2] 刘其斌[2] HUANG Qi-hang;YU Ben;LI Jian;LIU Jun-cai;HUANG Ling-mei;ZHANG Ren-guo;JIA Yi-wang;LIU Qi-bin(Guizhou Weitegao New Energy Technology Co.,Ltd.,Guizhou Nayong 553300;School of Materials and Metallurgy,Guizhou University,Guizhou Huaxi 550025,China)

机构地区：[1]贵州唯特高新能源科技有限公司,贵州纳雍553300 [2]贵州大学材料与冶金学院,贵州花溪550025

出　　处：《广州化工》2024年第9期32-36,共5页GuangZhou Chemical Industry

基　　金：电池级磷酸铁的清洁生产技术研究与示范(No:黔科合支撑[2021]一般494)。

摘　　要：文章以液相共沉淀法对粗品磷酸锂进行除杂、提纯,提纯后得到电池级磷酸锂。通过单一变量法对氢氧化钠浓度、氢氧化钠溶液滴加速度与表面活性剂对反应产物中杂质含量的影响进行研究,同时,对反应体系的温度与滴定后体系的pH值对反应产物提取率的影响进行研究。实验过程依次为将粗品磷酸锂溶于稀硫酸后过滤得到锂溶液,使用氢氧化钠调节锂溶液pH,使得磷酸锂沉淀,过滤、洗涤、干燥得到高纯度磷酸锂。得到磷酸锂中的钠含量随着氢氧化钠浓度的增加和其滴定速度的增加均呈现先下降后上升的趋势;PEG主要是使磷酸锂形成多孔结构,使磷酸锂中的钠离子更易于洗出;温度主要影响磷酸锂的提取率。通过实验得出氢氧化钠浓度为3 mol/L、氢氧化钠溶液滴加速度为2000 L/h、按0.17%比例添加PEG时杂质去除率最高。反应体系温度为90℃、反应完成后体系pH值为9时粗品磷酸锂的回收率最高。将提纯得到的磷酸锂与磷酸铁合成磷酸铁锂,其电化学性能完全达到行业要求。The crude lithium phosphate was purified by liquid phase coprecipitation,and battery grade lithium phosphate was obtained after purification.The effects of sodium hydroxide concentration,sodium hydroxide solution dropping speed and surfactant on the impurity content in the reaction products were studied by single variable method.At the same time,the effects of reaction system temperature and titrated system pH on the extraction rate of reaction products were studied.The experimental process was to dissolve the crude lithium phosphate in dilute sulfuric acid and filter it to obtain lithium solution.Sodium hydroxide was used to adjust the pH of lithium solution to make lithium phosphate precipitate,after filtering,washing and drying it,high-purity lithium phosphate was obtained.The results showed that the sodium content in lithium phosphate decreased first and then increased with the increase of sodium hydroxide concentration and titration rate.PEG was mainly used to make lithium phosphate form a porous structure,so that sodium ions in lithium phosphate can be washed out more easily.Temperature mainly affected the extraction rate of lithium phosphate.The experiment showed that the impurity removal rate was the highest when the concentration of sodium hydroxide was 3 mol/L,the dropping speed of sodium hydroxide solution was 2000 L/h,and the proportion of PEG added was 0.17%.When the temperature of the reaction system was 90℃ and the pH value of the finished system was 9,the recovery rate of crude lithium phosphate was the highest.Lithium iron phosphate was synthesized from purified lithium phosphate and iron phosphate,and its electrochemical performance fully met the requirements of the industry.

关 键 词：磷酸锂 NAOH 滴加速度 

分 类 号：TQ115[化学工程—无机化工]