本文關(guān)鍵詞： 廢舊鋰離子電池 正極材料 電解剝離 鋁箔 浸出 燕麥秸稈　出處：《中南大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：針對(duì)廢舊鋰離子電池正極材料回收中一些關(guān)鍵難題,論文提出電解剝離-生物質(zhì)酸浸回收新工藝。研究采用硫酸檸檬酸為電解液,帶鋁箔的正極條為陰極,鉑電極為陽(yáng)極,電解剝離-浸出,實(shí)現(xiàn)了電池粉與鋁箔剝離和部分鈷的浸出。收集殘余的浸出渣,采用燕麥秸稈粉為還原劑,用硫酸浸出渣中的鉆。新流程避免了酸浸出過程鋁箔的溶解帶來(lái)的后續(xù)分離鋁的難題,實(shí)現(xiàn)了鋁箔的資源化回收,另外新流程不需雙氧水為還原劑,過程簡(jiǎn)單經(jīng)濟(jì)安全。 論文研究了電解-硫酸剝離浸出工藝動(dòng)力學(xué)過程,研究表明浸出前期(5-30min)符合縮核模型,表觀活化能為7.32kJ/mol,后期(75-180min)為內(nèi)擴(kuò)散控制模型,表觀活化能17.05kJ/mol。電解浸出實(shí)驗(yàn)發(fā)現(xiàn),由于氧化鋁膜的溶解和氫氣泡的“吹動(dòng)”,正極電池粉在20～30min從鋁箔上剝落,此后,鈷的浸出能力逐漸減弱,電流效率逐漸降低。電解剝離最優(yōu)實(shí)驗(yàn)條件為：硫酸濃度20～30g/L,檸檬酸濃度36g/L,電流密度為200A/m2,電解剝離-浸出時(shí)間為30min。在此條件下可實(shí)現(xiàn)正極粉與鋁箔的分離,鈷的浸出率為40%左右,鋁箔溶解約2%,電流效率40～50%。 對(duì)于電解剝離后殘余的浸出渣,論文采用生物質(zhì)燕麥秸稈粉代替雙氧水作還原劑,用硫酸浸出。通過單因素實(shí)驗(yàn),得到最佳工藝條件為：液固比為10,單位質(zhì)量電池渣所需麥稈粉用量0.7g,硫酸濃度2mol/L,溫度90℃,燕麥秸稈粉粒徑為60～100目,電池渣中鉆的浸出率在99%以上。為了降低浸出液中的COD,本文設(shè)計(jì)了三級(jí)酸浸工藝,結(jié)果浸出液中Co2+的濃度達(dá)到50g/L以上,而COD濃度降至1.5g/L左右。論文對(duì)生物質(zhì)酸浸過程進(jìn)行動(dòng)力學(xué)研究,結(jié)果表明在浸出前期(0-20min)為縮核模型,而浸出后期(30～150min)受化學(xué)反應(yīng)控制為主的縮核模型控制。浸出前后粉渣的FT-IR檢測(cè)表明,燕麥秸稈粉含有豐富的木質(zhì)素、聚木糖、纖維素和半纖維素等的還原性物質(zhì),在浸出過程能替代雙氧水還原浸出鉆。 浸出液采用草酸沉鈷,工藝條件為：pH值1-2,溫度50-60℃,沉降時(shí)間1h,[C2O42-]/[Co2+]比值控制在1.05～1.1左右,鈷的沉降率達(dá)到92～95%,沉降得到草酸鈷產(chǎn)品經(jīng)分析合格。論文將草酸鉆用于制備鈷酸鋰正極材料,通過XRD分析晶格參數(shù)發(fā)現(xiàn),鈷酸鋰材料具有良好的電池性能。
[Abstract]:In view of some key problems in recovering cathode materials from waste lithium ion batteries, a new process of electrolytic stripping and recovery of biomass by acid leaching was proposed. Citric acid sulfate was used as electrolyte, positive electrode with aluminum foil as cathode and platinum electrode as anode. Electrolytic stripping and leaching of battery powder and aluminum foil and partial cobalt leaching were realized. Residual leaching slag was collected, and oat straw powder was used as reducing agent. The new process avoids the problem of the subsequent separation of aluminum caused by the dissolution of aluminum foil during acid leaching, and realizes the recovery of aluminum foil. In addition, the new process does not need hydrogen peroxide as reducing agent, and the process is simple, economical and safe. The kinetic process of electrolysis and sulfuric acid stripping leaching was studied in this paper. The results showed that the pre-leaching process was in accordance with the model of shrinking nucleus, the apparent activation energy was 7.32kJ / r / mol, the latter was 75-180min), and the apparent activation energy was 17.05kJ / mol. Due to the dissolution of aluminum oxide membrane and the "blowing" of hydrogen bubble, the positive electrode battery powder flakes off from the aluminum foil at 20 鈩，

本文編號(hào)：1547139