Wenzhi He

Cathode ray tube (CRT) recycling: current capabilities in China and research progress.

It is estimated that approximately 6,000,000 scrap TVs and 10,000,000 personal computers are generated each year in China. Cathode ray tubes (CRTs) from these machines consist of 85% glass (65% panel, 30% funnel and 5% neck glass). The leaded glass (funnel-24%, neck-30%) may seriously pollute the environment if it is not properly disposed of. In this paper, the past, current and future status of CRT dismantling technologies as well as the CRT glass recycling situation in China are presented and discussed. Recycling technology for waste CRTs in China is still immature. While the conventional CRT dismantling technologies have disadvantages from both economic and environmental viewpoints, some of the new and emerging treatments such as automatic optical sorting facilities that have been applied in developed countries offer advantages, and therefore should be transferred to China in the next few years to solve the CRT pre-processing problem. Meanwhile, because the demand for CRT glass closed-loop recycling is extremely limited, the authorities should take effective measures to improve CRT glass recycling rates and to facilitate a match to local conditions. Moreover, we also provide a broad review of the research developments in recycling techniques for CRT cullet. The challenge for the future is to transfer these environmentally friendly and energy-saving technologies into practice.

Leaching lithium from the anode electrode materials of spent lithium-ion batteries by hydrochloric acid (HCl)

Spent lithium-ion batteries (LIBs) are considered as an important secondary resource for its high contents of valuable components, such as lithium and cobalt. Currently, studies mainly focus on the recycling of cathode electrodes. There are few studies concentrating on the recovery of anode electrodes. In this work, based on the analysis result of high amount of lithium contained in the anode electrode, the acid leaching process was applied to recycle lithium from anode electrodes of spent LIBs. Hydrochloric acid was introduced as leaching reagent, and hydrogen peroxide as reducing agent. Within the range of experiment performed, hydrogen peroxide was found to have little effect on lithium leaching process. The highest leaching recovery of 99.4wt% Li was obtained at leaching temperature of 80°C, 3M hydrochloric acid and S/L ratio of 1:50g/ml for 90min. The graphite configuration with a better crystal structure obtained after the leaching process can also be recycled.

Hydrogen Production from Biomass Wastes by Hydrothermal Gasification

Abstract Biomass is a useful feed material for energy and chemical resources. Hydrothermal gasification of biomass wastes has been identified as a possible system for producing hydrogen. Supercritical and subcritical water has attracted much attention as an environmentally benign reaction medium and reactant. The main objective of this study is to assess and introduce the hydrothermal gasification of biomass wastes containing various quantities of the model compounds and real biomass. The decomposition of biomass, as a basis of hydrothermal treatment of organic wastes, is introduced. To eliminate chars and tars formation and obtain higher yields of hydrogen, catalyzed hydrothermal gasification of biomass wastes is summarized.

The development of WEEE management and effects of the fund policy for subsidizing WEEE treating in China

The consumption of electrical and electronic equipment is surging, so is the generation of waste electrical and electronic equipment (WEEE). Due to the large quantity, high potential risk and valuable capacity of WEEE, many countries are taking measures to regulate the management of WEEE. The environmental pollution and human health-harming problems caused by irregular treatment of WEEE in China make the government pay more and more attention to its management. This paper reviews the development of WEEE management in China, introduces the new policy which is established for WEEE recycling and especially analyzes the effectiveness of the policy, including huge recovery, formation of new recycling system, strict supervision to related enterprises, and the stimulation to public awareness. Based on the current achievement, some recommendations are given to optimize the WEEE management in China.

Estimating the impact of the home appliances trade-in policy on WEEE management in China

The ever-increasing amount of waste electric and electronic equipment (WEEE) has become a global problem. In view of the deleterious effects of WEEE on the environment and the valuable materials that can be reused in them, many countries have focused their attention on the management of WEEE and the recovery technologies of WEEE. The Chinese government has been active in creating a legislative and institutional framework to realize WEEE recycling. In June 2009, Chinese government launched home appliances and electronics trade-in implementation solution. This paper elaborates the home appliances trade-in policy and its significant impact on the WEEE management. The trade-in policy is not only conducive to expanding the consumption demand and promoting the balance of domestic and overseas demand, but also favorable to improving the energy efficiency and reducing environmental pollution. Under this policy, China has successfully established an effective WEEE recycling system, using the financial means and network design. Experiences gained from the trade-in policy have shown that management systems of WEEE need to be designed and implemented in a multi-stakeholder dialogue.

Recovering copper from spent lithium ion battery by a mechanical separation process

Based on the structure of lithium-ion batteries (LIBs), the electrode materials were separated from spent LIBs with aim to recycle all valuable components as possible. The spent LIBs were dismantled first, then the mechanical pulverization and sieving process was adopted in the separation of anodes. Owing to low bonding force between graphite carbon particles and copper foil, graphite carbon can easily drop off and be separated when anode materials were struck. The results showed that after shredding and sieving, most copper was concentrated in the particle size above 0.59 mm (below 30 mesh), the copper recovery rate reached 93.10 wt %, and the content of copper was 95.40 % at the condition of 3 min pulverization. Further separation of the anode scraps from 0.590 mm to 0.177 mm was carried out using fluidized bed technology. Approximately 92.30 wt % of copper in anode particles from 0.590 mm to 0.177 mm can be recovered by a gas-fluidized bed separator at the selected optimal gas velocity (1.00 m·s−1).

The situation of waste mobile phone management in developed countries and development status in China

With the rapid development of electronic industry and improvement of living standards, a large number of waste mobile phones were generated. According to statistics, approximately 400million waste mobile phones are generated each year in the world, and 25% of that are contributed by China. Irregular disposal of waste mobile phones will do great harm to environment and human health, while at the same time recycling of them has the potential for high profits. Given the enormous quantity, great harm and resource properties, developed countries have taken necessary measures to manage waste mobile phones. As the largest developing country, China has also set out to pay close attention to waste mobile phones. This paper reviewed the situation ofwaste mobile phone management in the developed countries, focused on the development of waste mobile phone management in China, and analyzed existing problems. In light of the successful experience of the developed countries, some suggestions were proposed to promote the waste mobile phone management in China and worked as a valuable reference for other countries.

The integrated design and optimization of a WEEE collection network in Shanghai, China

An integrated formal collection and recycling network is a significant concern to achieve efficient management of waste electrical and electronic equipment (WEEE). This study, which aimed to investigate the present problems of WEEE recycling in China, proposes the application of a comprehensive solution approach to address a complete WEEE collection and transportation network in Shanghai, China. The methodologic steps regard three things: identification of WEEE collection sites and transit sites with quadratic optimizing models solved by exact algorithm; vehicle routing planning with a modified ant colony algorithm; and defining of minimum transportation cycles and proper shipping arrangements. The rounded WEEE collection network is presented as technical support and a demonstration of further planning and construction of the WEEE recycling system in China.

An assessment on Shanghai's energy and environment impacts of using MARKAL model

Energy is essential for the development of a city. The energy structure of China, dominated by coal, has caused serious problems, such as resource depletion, environmental pollution, and climate change. These problems have posed severe challenges to the sustainable development of mega—cities such as Shanghai. In order to ensure security of energy supply and alleviate the corresponding environmental pollution, these cities should effectively restructure their energy supply. This paper quantitatively analyzed the future energy consumption demand in Shanghai and its effects on environmental quality based on the MARKAL model with the aim of providing theoretical support for the government decision regarding energy policy, energy technology, adjustment of energy supply structure, etc. Different scenarios have been set up in light of the natural gas distributed supply system, clean and efficient coal-fired power technologies, energy-saving of industrial boilers technologies, Integrated Gasification Combined Cycle (advanced power generation technology), and wind power technologies. The results obtained by the MARKAL model show that total consumption of the whole society energy in Shanghai will reach 143 572 700 tons of standard coal in 2015, and 199 645 800 tons of standard coal in 2020. Thus, the future demand for energy consumption is huge astronomical, with about an average annual growth rate of 4%. The consumption of coal and other primary energy could decline by improving the energy efficiency and increasing renewable energy use, which would reduce pollutants emissions. At the same time, Shanghai should continue research on carbon dioxide emissions technology and its application in response to climate change.

Resource recovery from waste LCD panel by hydrothermal transformation of polarizer into organic acids

Based on the significant advantages of hydrothermal technology, it was applied to treat polarizer from the waste LCD panel with the aim of transforming it into organic acids (mainly acetic acid and lactic acid). Investigation was done to evaluate the effects of different factors on yields of organic acids, including the reaction temperature, reaction time and H2O2 supply, and the degradation process of polarizer was analyzed. Liquid samples were analyzed by GC/MS and HPLC, and solid-phase products were characterized by SEM and FTIR. Results showed that at the condition of temperature 300 °C and reaction time 5 min, the organic materials reached its highest conversion rate of 71.47% by adding 0.2 mL H2O2 and acetic acid was dominant in the products of organic acids with the yield of 6.78%. When not adding H2O2 to the system, the yields of lactic and acetic acid were respectively 4.24% and 3.80% at a nearly equal degree, they are suitable for esterification to form ethyl lactate instead of separating them for this case. In the hydrothermal process, polarizer was first decomposed to monosaccharides, alkane, etc., and then furfural and acids are produced with further decomposition.