硫酸氢钾焙烧法回收NCM622正极材料中金属的研究

Study on Extraction of Metal from NCM622 Cathode Material by Potassium Bisulfate Roasting

高镍三元正极材料LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)因具有良好的可逆容量、好的化学稳定性等优点,近年来在高能量密度的新能源汽车车用电池中获得了产业化应用。针对新能源汽车退役动力电池正极材料NCM622中的有价金属Li,Ni,Co,Mn的高效回收,提出了一种采用NCM622与硫酸氢钾(KHSO_(4))混合后焙烧,然后水浸出提取金属元素的新型工艺,并研究了焙烧过程金属元素赋存形式的演变规律及焙烧工艺条件对金属提取率的影响。研究结果表明:NCM622和KHSO_(4)的混合物在600℃焙烧0.5 h后,Li,Ni,Co,Mn元素赋存形式不再以LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)存在,而是转变为LiKSO_(4)和Ni,Co,Mn的氧化物或硫酸盐。焙烧产物中Ni,Co,Mn倾向于以低价态+2价形式存在。当NCM622与KHSO_(4)的混合质量比为1∶4.63时,经过焙烧-水浸,Li,Ni,Co,Mn元素的浸出率分别为99.93%,97.97%,98.36%,97.13%。

In recent years,the ternary cathode material LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)with high nickel content has been industrialized in high energy density new energy vehicle batteries due to its excellent reversible capacity and chemical stability.In view of the efficient recovery of valuable metals Li,Ni,Co,Mn in the cathode material NCM622 of retired power batteries for new energy vehicles,this paper proposes a new process that uses NCM622 and potassium bisulfate(KHSO_(4))to mix and roast,and then water leaching to extract metal elements from the spent lithium ion power batteries.The research results show that after the mixture of NCM622 and KHSO_(4)is roasted at 600℃for 0.5 hours,Li,Ni,Co,and Mn elements are no longer exist in the form of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2),but transformed into LiKSO_(4),and the oxide or sulfate forms of Ni,Co,and Mn.Ni,Co,and Mn elements in the calcined products tend to exist in low valence states.When the mixed mass ratio of NCM622 and KHSO_(4)is 1∶4.63,the extraction rates of Li,Ni,Co,and Mn elements are 99.93%,97.97%,98.36%,and 97.13%after roasting and water leaching,respectively.