Xianlai Zeng

Recycling of Spent Lithium-Ion Battery: A Critical Review

Lithium-ion battery (LIB) applications in consumer electronics and electric vehicles are rapidly growing, resulting in boosting resources demand, including cobalt and lithium. So recycling of batteries will be a necessity, not only to decline the consumption of energy, but also to relieve the shortage of rare resources and eliminate the pollution of hazardous components, toward sustainable industries related to consumer electronics and electric vehicles. The authors review the current status of the recycling processes of spent LIBs, introduce the structure and components of the batteries, and summarize all available single contacts in batch mode operation, including pretreatment, secondary treatment, and deep recovery. Additionally, many problems and prospect of the current recycling processes will be presented and analyzed. It is hoped that this effort would stimulate further interest in spent LIBs recycling and in the appreciation of its benefits.

Novel approach to recover cobalt and lithium from spent lithium-ion battery using oxalic acid

With the booming of consumer electronics (CE) and electric vehicle (EV), a large number of spent lithium-ion battery (LIBs) have been generated worldwide. Resource depletion and environmental concern driven from the sustainable industry of CE and EV have motivated spent LIBs should be recovered urgently. However, the conventional process combined with leaching, precipitating, and filtering was quite complicated to recover cobalt and lithium from spent LIBs. In this work, we developed a novel recovery process, only combined with oxalic acid leaching and filtering. When the optimal parameters for leaching process is controlled at 150 min retention time, 95 °C heating temperature, 15 g L(-1) solid-liquid ratio, and 400 rpm rotation rate, the recovery rate of lithium and cobalt from spent LIBs can reach about 98% and 97%, respectively. Additionally, we also tentatively discovered the leaching mechanism of lithium cobalt oxide (LiCoO2) using oxalic acid, and the leaching order of the sampling LiCoO2 of spent LIBs. All the obtained results can contribute to a short-cut and high-efficiency process of spent LIBs recycling toward a sound closed-loop cycle.

Ecodesign in Consumer Electronics: Past, Present, and Future

In the past 20 years, the booming consumer electronics (CE) industry has been rapidly changing the economic and social landscape. This phenomenon is partly raised by the development of ecodesign, which is dedicated to improving the environmental performance of CE, throughout its life cycle. The theory and application of ecodesign have both been improved and expanded, owing largely to the development of more environmentally friendly materials, newly emerging technology, and legislation mandating better handling of CE—both in manufacturing and in waste treatment. Yet many challenges and opportunities remain, including the pressure that the huge CE market exerts on resources; new materials and technology such as carbon nanomaterial and the Internet of Things; the need to balance business profit with environmental impacts and benefits; and a significant shift of focus in the processing of electronic waste—from dismantling for recycling to disassembly for remanufacturing. This critical review article can help create sustainable development strategies from a local solution to global opportunities that will elevate ecodesign or design for environment to a new level in new materials selecting, CE industry development, integrated e-waste management, and legislation.

Rare Earth Elements Recovery from Waste Fluorescent Lamps: A Review

Rare earth elements (REEs) are used in a wide range of products. The global demand for REEs is growing at a rate of 3.7–8.6% annually. Yttrium (Y), europium (Eu), cerium (Ce), lanthanum (La), and terbium (Tb) are used in the phosphors for fluorescent lamps (FLs). The authors review the challenges and techniques associated with the recycling and recovery of REEs in phosphors from waste FLs. The recovery rate and grade of resultant products and the processing costs are the primary factors to be considered regarding trichromatic phosphors enrichment and monochrome phosphor separation. Currently, most researchers have focused on the recovery of Y and Eu from red phosphor using hydrometallurgy methods, and on the difficulties of leaching Ce, La, Tb, and Eu in green and blue phosphors. The final recovery rate of Y and Eu can reach more than 80%, but a higher rate is desirable, considering the total value of the REEs in FLs. Studies on improving the leaching behavior of phosphors have been conducted; however, they present problems such as energy and agents consumption, and generation of viscous solution of silicate. Some pyrometallurgy and electrometallurgy approaches are also discussed.

Environmental pollution of electronic waste recycling in India: A critical review

The rapid growth of the production of electrical and electronic products has meant an equally rapid growth in the amount of electronic waste (e-waste), much of which is illegally imported to India, for disposal presenting a serious environmental challenge. The environmental impact during e-waste recycling was investigated and metal as well as other pollutants [e.g. polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs)] were found in excessive levels in soil, water and other habitats. The most e-waste is dealt with as general or crudely often by open burning, acid baths, with recovery of only a few materials of value. As resulted of these process; dioxins, furans, and heavy metals are released and harmful to the surrounding environment, engaged workers, and also residents inhabiting near the sites. The informal e-waste sectors are growing rapidly in the developing countries over than in the developed countries because of cheapest labor cost and week legislations systems. It has been confirmed that contaminates are moving through the food chain via root plant translocation system, to the human body thereby threatening human health. We have suggested some possible solution toward in which plants and microbes combine to remediate highly contaminated sites.

Innovating e-waste management: From macroscopic to microscopic scales.

Waste electrical and electronic equipment (WEEE or e-waste) has become a global problem, due to its potential environmental pollution and human health risk, and its containing valuable resources (e.g., metals, plastics). Recycling for e-waste will be a necessity, not only to address the shortage of mineral resources for electronics industry, but also to decline environmental pollution and human health risk. To systematically solve the e-waste problem, more attention of e-waste management should transfer from macroscopic to microscopic scales. E-waste processing technology should be significantly improved to diminish and even avoid toxic substance entering into downstream of material. The regulation or policy related to new production of hazardous substances in recycled materials should also be carried out on the agenda. All the findings can hopefully improve WEEE legislation for regulated countries and non-regulated countries.

A novel dismantling process of waste printed circuit boards using water-soluble ionic liquid

Recycling processes for waste printed circuit boards (WPCBs) have been well established in terms of scientific research and field pilots. However, current dismantling procedures for WPCBs have restricted the recycling process, due to their low efficiency and negative impacts on environmental and human health. This work aimed to seek an environmental-friendly dismantling process through heating with water-soluble ionic liquid to separate electronic components and tin solder from two main types of WPCBs-cathode ray tubes and computer mainframes. The work systematically investigates the influence factors, heating mechanism, and optimal parameters for opening solder connections on WPCBs during the dismantling process, and addresses its environmental performance and economic assessment. The results obtained demonstrate that the optimal temperature, retention time, and turbulence resulting from impeller rotation during the dismantling process, were 250 °C, 12 min, and 45 rpm, respectively. Nearly 90% of the electronic components were separated from the WPCBs under the optimal experimental conditions. This novel process offers the possibility of large industrial-scale operations for separating electronic components and recovering tin solder, and for a more efficient and environmentally sound process for WPCBs recycling.

Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries

Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fouriers law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling.

Spent rechargeable lithium batteries in e-waste: composition and its implications

The amount of spent rechargeable lithium batteries (RLBs) is growing rapidly owing to wide application of these batteries in portable electronic devices and electric vehicles, which obliges that spent RLBs should be handled properly. Identification of spent RLBs can supply fundamental information for spent RLBs recycling. This study aimed to determine the differences of physical components and chemical compositions among various spent RLBs. All the samplings of RLBs were rigorously dismantled and measured by an inductive coupled plasma atomic emission spectrometer. The results indicate that the average of total weight of the separator, the anode and the cathode accounted for over 60% of all the RLBs. The weight ratio of valuable metals ranged from 26% to 76%, and approximately 20% of total weight was Cu and Al. Moreover, no significant differences were found among different manufacturers, applications, and electrolyte types. And regarding portable electronic devices, there is also no significant difference in the Co-Li concentration ratios in the leaching liquid of RLBs.

Relationship between e-waste recycling and human health risk in India: a critical review

Informal recycling of waste (including e-waste) is an emerging source of environmental pollution in India. Polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PBDEs), and heavy metals, among other substances, are a major health concern for workers engaged in waste disposal and processing, and for residents living near these facilities, and are also a detriment to the natural environment. The main objective of this review article was to evaluate the status of these impacts. The review found that, huge quantity of e-waste/waste generated, only a small amount is treated formally; the remainder is processed through the informal sector. We also evaluated the exposure pathways, both direct and indirect, and the human body load markers (e.g., serum, blood, breast milk, urine, and hair), and assessed the evidence for the association between these markers and e-waste exposure. Our results indicated that the open dumping and informal e-waste recycling systems should be replaced by the best available technology and environmental practices, with proper monitoring and regular awareness programs for workers and residents. Further and more detailed investigation in this area is also recommended.