An attempt of a new method used in newly emerging waste treatment, i.e. LCD and Li-ion battery, and non-materials.

After the entry into the 21st centenary, liquid crystal display (LCD) has been currently hold the mainstream position of the flat panel displays (FPDs), and widely used in notebook computers and increasingly popularized in desktop computer monitor and TV. E.g., in China, a volume of 62.49 million units of notebook computer with LCD screen was produced in 2006, and kept rapid increase (NBSC, 2007). As LCDs are already on the market for 3-5 years lifespan, larger quantities of the LCDs are coming into their End-of-Life stage for treatment. However, many hazardous substances used in LCD, such as mercury in cold cathode fluorescent lamps (CCFL) and liquid crystal materials, would produce significant adverse impacts to human health and the eco-environment if improperly disposed (Arun B., et al., 2004; Marcelo F. C. et al., 2008; Chang T.C., et al., 2007; Veriansyah B, et al., 2007). But on the other hand, many reusable materials contained in LCD, such as glass, plastic, and precious metals (indium), could be recovered (Li J. et al., 2006, Kang H.Y. et al., 2006). Since the landfilling and incineration of scrap LCDs not only lead a waste of resources, but also generate environmental impacts, the best available technologies for treatment LCD are urgently required.

LCD panel is the main part of LCD screen after primary dismantling. Generally, LCD panel consists of a glass substrate and a back light module. The surface of glass substrate is attached with polarizing film, and the inner side is coated with functional films called as Indium-Tin Oxide (ITO). As the major functional units of LCD, glass substrate accounted for 40-50 wt%, and the back light module accounts for another 35-40 wt% (including light guide plate and backlight). The light guide plate consists of polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), a piece of prism, and a small piece of printed circuit board (PCB) (Fisher, M. et al., 2004). CCFL used as backlight is parallelly loaded along one side or both sides to length direct of the light guide plate. Metals frame (made of zinc, iron or aluminum) were usually found outside of glass substrate and back light module in order to protect structure.

By far, many recycling technologies have been studied and developed for LCD panel treatment (Fraunholc Z., 2006; Li J. et al., 2006; Steiner, 2006; Qing W., 2004; Lee, 2004)

In above-reported technologies, the mechanical crushing was usually used as the primary step for the treatment of LCD panel. While it was feasible to conduct, the recovery rate of valuable materials was quite low. Moreover, the toxic materials and recyclable materials were usually treated together, which inevitably led the removal of toxic materials ineffectively when recycling the reusable materials. Thus, how to develop innovated technologies, and transfer the laboratory scale studies to best available technologies which could be applied into industrial practice by an environmental sound method, is a huge challenge faced by recycler.

To improve the efficiency of valuable material recovery from waste LCD but with minor environmental impacts, a combination mechanical technology was proposed after the simple dismantling (see figure 7).

Aiming to remove or separate toxic substances through an environmental and feasible method and recover the valuable materials efficiently. Firstly, during the dismantling stage, PMMA, PET, PC, PCBs and CCFL were removed manually. Then, key technological processes divided into three stages have been studied respectively, including separation of the polarizing film by thermal shock method with whole glass substrate, removal of liquid crystals through ultrasonic washing after crushing, and recovery for indium metal by acid extraction.

Three key technological processes were separately studied, including separation of the polarizing film by thermal shock, removal of liquid crystals by the ultrasonic washing, and solvent extraction recovery process for indium respectively. The results show that valuable components (e.g. Indium) and harmful substance (e.g. liquid crystals) could be efficiently recovered or removed. See figure 8.

Lithium-ion batteries (LIBs) are widely used in laptops, mobile phones, video-cameras and other portable electronics. The use of LIBs (Figure 9), which consists of crust, electrodes (usually copper foil for negative electrode and aluminum foil for positive electrode), electrolyte, polymer (Contestabile, M., 2001; Lee, C. K., 2003), increased sharply in recent years because of their function update and cost decrease. It’s necessary to recycle .lithium cobalt oxide (LiCoO2), which is adopted as cathode active material, because Li and Co are both precious and hazardous to environment. Up to now, some processes have been reported to reclaim Co, Li, Cu, and Al from spent LIBs, but only a few of them stepped into industrial practices (Xu, J., 2008; Espinos D., 2004).

In the pilot project conducted in demonstration city, a new process with regarding to recover Co from spent Li-ion batteries was addressed by using a combination technology of crushing, ultrasonic washing, acid leaching and precipitation (see figure 10).

This proposed recycling process of spent LIBs could achieve a good material recovery result. The components of the separated electrodes consist of a 28.28% Co and 2.46% impurities (such as Al, Fe, and Cu). See figure 11.