磷酸铁锂正极废粉提锂后的硫酸锂除磷和除氟研究  

Study on Fluoride and Phosphate Removal from Lithium Sulfate of Spent Lithium Iron Phosphate Cathode Powder after Delithiation

作　　者：李立平 黄铿齐 李煜乾 谭泽 曾德文[2] LI Liping;HUANG Kengqi;LI Yuqian;TANG Ze;ZENG Deweng(Guangdong Guanghua Sci-tech Co.,Ltd.,Shantou 515000,China;College of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China)

机构地区：[1]广东光华科技股份有限公司,广东汕头515000 [2]中南大学化学化工学院,湖南长沙410083

出　　处：《化工技术与开发》2022年第1期67-73,77,共8页Technology & Development of Chemical Industry

基　　金：广东省重点领域研发计划项目(2020B090919003)。

摘　　要：针对废旧磷酸铁锂正极粉经硫酸浸出后得到的硫酸锂中氟、磷含量高的问题,开展了水合金属氧化物吸附除杂工作,重点研究了吸附剂种类、吸附剂用量、溶液pH、吸附温度、吸附时间、共存阴离子浓度等因素对F^(-)、PO_(4)^(3-)吸附规律的影响。结果表明,La(OH)_(3)的吸附效率优于Zr(OH)_(4)或Ce(OH)_(4)。随着吸附剂用量或溶液pH的提高,La(OH)_(3)对F^(-)、PO_(4)^(3-)的吸附容量降低;提高吸附温度或延长吸附时间有利于提高F^(-)、PO_(4)^(3-)的吸附率。此外,提高共存阴离子浓度,有利于强化对同离子的吸附,而对其他共存阴离子的吸附过程有一定的抑制作用。在溶液pH=3.0的体系中,La(OH)_(3)为用量3.0 g·L^(-1)、吸附温度60℃、吸附时间60 min的条件下,F^(-)、PO_(4)^(3-)的吸附容量为48.1mg·g^(-1)和49.8mg·g^(-1),吸附率分别为96.0%和97.4%。XRD和EDS结果表明,F^(-)、PO_(4)^(3-)在La(OH)_(3)上的吸附,主要是与OH-间发生了配体交换反应。La(OH)_(3)对F^(-)、PO_(4)^(3-)的吸附容量和选择性高,可实现深度除氟和除磷的目的。Obtained by delithiation of spent lithium iron phosphate cathode powder with sulfate acid,the high fluoride-content and phosphate-content of lithium sulfate was treated with hydrated metal oxide,and the effects of adsorbent type,dosage,pH,temperature,tine as well as co-existing anions on the adsorption performance of F^(-)and PO_(4)^(3-)were comprehensively investigated.The results showed that the adsorption rate for La(OH)_(3)was better than that of Zr(OH)_(4)or Ce(OH)_(4).It was observed that La(OH)_(3)showed lower adsorption capacity with the increase of dosage or pH.Temperature and reaction time were beneficial for the removal rate of Fand PO_(4)^(3-).In addition,high concentration of co-existing anions was beneficial for promoting the adsorption capacity of same anion,while inhibited that of co-existing anions.Under the condition including pH value was 3.0,La(OH)_(3)was 3.0 g/L,temperature was 60℃and reaction time was 60 min,adsorption capacity of F^(-)and PO_(4)^(3-)reached 48.1mg/g and 49.8mg/g,while the removal efficiency were measured as 96.0%and 97.4%,respectively.XRD characterization and EDS analysis demonstrated that F^(-)and PO_(4)^(3-)on La(OH)_(3)could be attribute to ligand exchange with OH-.The La(OH)_(3)adsorbent showed high adsorption capacity and selectivity in fluoride removal and phosphate removal,indicated a promising adsorbent in deep defluorination and dephosphorization.

关 键 词：硫酸锂 La(OH)_(3) 吸附剂 除氟 除磷 

分 类 号：X789[环境科学与工程—环境工程]