PDF(Pubmed)
Abstract：
In recent years, the demand for lithium-ion batteries (LIBs) has been increasing rapidly. Conventional recycling strategies (based on pyro- and hydrometallurgy) are damaging for the environment and more sustainable methods need to be developed. Bioleaching is a promising environmentally friendly approach that uses microorganisms to solubilize metals. However, a bioleaching-based technology has not yet been applied to recover valuable metals from waste LIBs on an industrial scale. A series of experiments was performed to improve metal recovery rates from an active cathode material (LiCoO2; LCO). (i) Direct bioleaching of ≤0.5 % LCO with two prokaryotic acidophilic consortia achieved >80 % Co and 90 % Li extraction. Significantly lower metal recovery rates were obtained at 30 °C than at 45 °C. (ii) In contrast, during direct bioleaching of 3 % LCO with consortia adapted to elevated LCO levels, the 30 °C consortium performed significantly better than the 45 °C consortium, solubilizing 73 and 93 % of the Co and Li, respectively, during one-step bioleaching, and 83 and 99 % of the Co and Li, respectively, during a two-step process. (iii) The adapted 30°C consortium was used for indirect leaching in a low-waste closed-loop system (with 10 % LCO). The process involved generation of sulfuric acid in an acid-generating bioreactor (AGB), 2-3 week leaching of LCO with the biogenic acid (pH 0.9), selective precipitation of Co as hydroxide, and recirculation of the metal-free liquor back into the AGB. In total, 58.2 % Co and 100 % Li were solubilized in seven phases, and >99.9 % of the dissolved Co was recovered after each phase as a high-purity Co hydroxide. Additionally, Co nanoparticles were generated from the obtained Co-rich leachates, using Desulfovibrio alaskensis, and Co electrowinning was optimized as an alternative recovery technique, yielding high recovery rates (91.1 and 73.6% on carbon felt and roughened steel, respectively) from bioleachates that contained significantly lower Co concentrations than industrial hydrometallurgical liquors. The closed-loop system was highly dominated by the mixotrophic archaeon Ferroplasma and sulfur-oxidizing bacteria Acidithiobacillus caldus and Acidithiobacillus thiooxidans. The developed system achieved high metal recovery rates and provided high-purity solid products suitable for a battery supply chain, while minimizing waste production and the inhibitory effects of elevated concentrations of dissolved metals on the leaching prokaryotes. The system is suitable for scale-up applications and has the potential to be adapted to different battery chemistries.
摘要：
近年来,锂离子电池（LIBs）的需求一直在快速增长。传统的回收策略（基于高温和湿法冶金）正在破坏环境，需要开发更可持续的方法。生物浸出是一种有前途的环境友好的方法，使用微生物来溶解金属。然而,基于生物浸出的技术尚未应用于工业规模的废物LIB中回收有价值的金属。进行一系列实验以提高从活性阴极材料(LiCoO2;LCO)的金属回收率。(i)用两个原核生物嗜酸性聚生体直接浸取≤0.5%LCO,达到>80%Co和90%Li提取。在30°C下获得的金属回收率明显低于在45°C下获得的金属回收率。(ii)相比之下，在使用适应升高的LCO水平的财团直接生物浸出3%LCO期间，30°C联盟的表现明显优于45°C联盟，溶解73％和93％的Co和Li，分别,在一步生物浸出过程中，83％和99％的公司和Li，分别,在两步过程中。（iii）适应的30°C财团用于低废物闭环系统（具有10％LCO）中的间接浸出。该过程涉及在产酸生物反应器（AGB）中产生硫酸，用生物酸（pH0.9）浸出LCO2-3周，Co作为氢氧化物的选择性沉淀，并将无金属液体再循环回到AGB中。总的来说,58.2%的Co和100%的Li溶解在七个阶段，并且>99.9%的溶解的Co在每个阶段之后作为高纯度Co氢氧化物被回收。此外,从获得的富Co渗滤液中产生Co纳米颗粒，使用阿拉斯加脱硫弧菌，并将Co电积优化为替代回收技术，产生高回收率(碳毡和粗钢的回收率分别为91.1%和73.6%，分别）来自含Co浓度明显低于工业湿法冶金液的生物渗滤液。闭环系统主要由混合营养的古生菌和硫氧化细菌酸性硫杆菌和氧化硫硫杆菌主导。开发的系统实现了高金属回收率，并提供了适用于电池供应链的高纯度固体产品，同时最大程度地减少废物的产生以及升高的溶解金属浓度对浸出原核生物的抑制作用。该系统适用于放大应用，并有可能适应不同的电池化学。
