LiFePO_(4)-Na_(2)CO_(3)体系焙烧过程物相变化及Li、Fe回收研究  

Study on Phase Transformation in LiFePO_(4)-Na_(2)CO_(3) Roasting System and Recovery of Li and Fe

作　　者：贾鹏升 王大辉[1] 陈怀敬[2] 祁万虎 武国真 JIA Pengsheng;WANG Dahui;CHEN Huaijing;QI Wanhu;WU Guozhen(State Key Laboratory of Advance Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;College of Science,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学理学院,兰州730050

出　　处：《有色金属工程》2024年第4期90-96,共7页Nonferrous Metals Engineering

基　　金：国家自然科学基金资助项目(51864032);沈阳材料科学国家(联合)实验室-有色金属加工与再利用国家重点实验室联合基金(18LHZD002)。

摘　　要：LiFePO_(4)作为正极材料在电动汽车动力电池中获得广泛使用,报废后再利用理论和工艺是当前研究的热点问题。提出了一种采用碱性焙烧联合酸性浸出从LiFePO_(4)中提取Li、Fe的新型回收方法,并对LiFePO_(4)-Na_(2)CO_(3)体系焙烧过程中的物相变化进行了研究。结果表明:LiFePO_(4)-Na_(2)CO_(3)作用体系以质量比1∶0.67混合在800~950℃焙烧,过程是包含化合物分解反应、氧化反应及化合物生成反应等反应类型的复杂反应,焙烧产物的物相组成为Fe2O3、Fe3O4、NaLi2PO4、LiNa5(PO4)2。浸出液使用磷酸溶液(pH=0)、浸出温度50℃、浸出时间60 min、液固比为20 mL/g,并用磷酸控制浸出终止pH=1的条件下,焙烧产物中Li的浸出率均大于98%,Fe的浸出率低于9%。LiFePO_(4)is widely used as a positive electrode material in electric vehicle power batteries,and its recycling theory and process after scrapping are currently a hot research topic.This paper proposes a new recovery method for extracting Li and Fe from LiFePO_(4)using alkaline roasting combined with acidic leaching,and studies the phase transformation during the roasting process of the Na_(2)CO_(3)-LiFePO_(4)system.The results showed that the Na_(2)CO_(3)-LiFePO_(4)reaction system was mixed at a mass ratio of 1∶0.67 and calcined at 800~950℃.The process was a complex reaction involving compound chemical decomposition,oxidation reaction and compound formation reaction.The phase composition of the calcined product was Fe 2O 3,Fe_(3)O_(4),NaLi 2PO_(4),LiNa 5(PO_(4))2.Under the conditions of using phosphoric acid solution(pH=0),leaching temperature of 50℃,leaching time of 60 minutes,and liquid-solid ratio of 20 mL/g,and using phosphoric acid to control the leaching termination pH=1,the leaching rate of Li in the calcined products is greater than 98%,while the leaching rate of Fe is less than 9%.

关 键 词：废旧锂离子动力电池 LiFePO_(4) 焙烧 金属回收 物相变化 

分 类 号：TG450.40[金属学及工艺—焊接]