Yufeng Wu

Recent development of recycling lead from scrap CRTs: A technological review.

Cathode ray tubes (CRTs) contain numerous harmful substances with different functions. Lead is found in the funnel glass of CRTs. Improperly treated toxic lead may pose significant risks to human health and the environment. This paper reviews and summarizes existing technological processes on the recycling of lead from waste CRTs, including pyrometallurgy, hydrometallurgy, and product-regeneration. The present situation, advantages, and disadvantages of these techniques are described in detail. Generally, pyrometallurgy shows better practicability in recovery lead from waste CRT than hydrometallurgy and hydrometallurgy, in view of environmental impact, energy-consumption, product formats and safety and maturity of technology. Moreover, the gaps in the existing technologies were identified and recommendations for future research were provided.

An evaluation of the potential yield of indium recycled from end-of-life LCDs: A case study in China

With the advances in electronics and information technology, China has gradually become the largest consumer of household appliances (HAs). Increasingly, end-of-life (EOL) HAs are generated in China. EOL recycling is a promising strategy to reduce dependence on virgin production, and indium is one of the recycled substances. The potential yield of indium recycling has not been systematically evaluated in China thus far. This paper estimates the potential yield of recycled indium from waste liquid crystal displays (LCDs) in China during the period from 2015 to 2030. The quantities of indium that will be used to produce LCDs are also predicted. The estimates focus on the following three key LCD waste sources: LCD TVs, desktop computers and portable computers. The results show that the demand for indium will be increasing in the near future. It is expected that 350 tonnes of indium will be needed to produce LCDs in China in 2035. The indium recycled from EOL LCDs, however, is much less than the demand and only accounts for approximately 48% of the indium demand. The sustainable index of indium is always less than 0.5. Therefore, future indium recycling efforts should focus on the development of recycling technology and the improvement of the relevant policy.

The lead-acid battery industry in China: outlook for production and recycling

In 2013, more than four million (metric) tons (MT) of refined lead went into batteries in China, and 1.5 MT of scrap lead recycled from these batteries was reused in other secondary materials. The use of start-light-ignition (SLI), traction and energy storage batteries has spread in China in recent decades, with their proportions being 25.6%, 47.2% and 27.2%, respectively, in 2012. The total production of these batteries increased from 296,000 kVAh in 2001 to 205.23 MkVAh in 2013, with manufacturing located mainly in the middle and eastern provinces of the country. In this paper, we find that the market share of SLI batteries will decrease slightly, the share of traction batteries will continuously increase with the emergence of clean energy vehicles, and that of energy storage batteries will increase with the development of the wind energy and photovoltaic industries. Accounting for lead consumption in the main application industries, and the total social possession, it is calculated that used lead batteries could generate 2.4 MT of scrap lead in 2014, which is much higher than the 1.5 MT that was recycled in 2013. Thus, the current recycling rate is too low. It is suggested that while building large-scale recycling plants, small-scale plants should be banned or merged.

Recycling of indium from waste LCD: A promising non-crushing leaching with the aid of ultrasonic wave

The tremendous amount of end-of-life liquid crystal displays (LCDs) has become one of the prominent sources of waste electrical and electronic equipment (WEEE) in recent years. Despite the necessity of safe treatment, recycling indium is also a focus of waste LCD treatment because of the scarcity of indium. Based on the analyses of the structure of Indium Tin Oxide (ITO) glass, crushing is demonstrated to be not required. In the present research, a complete non-crushing leaching method was firstly adopted to recycle indium from waste LCDs, and the ultrasonic waves was applied in the leaching process. The results demonstrated that indium can be leached efficiently with even a low concentration of chloride acid (HCl) without extra heating. About 96.80% can be recovered in 60mins, when the ITO glass was leached by 0.8MHCl with an enhancement of 300W ultrasonic waves. The indium leaching process is abridged free from crushing, and proves to be of higher efficiency. In addition, the ultrasonic wave influence on leaching process was also explained combing with micron-scale structure of ITO glass.

Eco-friendly Selective Synergistic Extraction Rare-Earths from Waste CRT Phosphor Powder Sulfuric Acid Leachate with Imidazolium-Based Ionic Liquid [OMIm] [PF 6 ] and Extractant Cyanex272

Considering the benefits of resource, environment and economy, recycling secondary rare earth resources is becoming an extremely significant resource regeneration way. In this paper, we reported a novel synergistic extraction system combining ionic liquid [OMIm] [PF6] and extractant Cyanex272 to separate and purify the REE from the leachate of waste CRT phosphor powder. Some extraction parameters were studied including extraction acidity, the ratio of organic phase to aqueous phase, the ratio of Cyanex272 and [OMIm] [PF6], extraction time and extraction temperature. The optimal parameters of the extraction process was obtained as extraction acidity 0.2 mol/L, the ratio of organic phase to aqueous phase 1:5, the ratio of Cyanex272 and [OMIm]PF6 XC = 0.4, extraction time 10 min and extraction temperature 25 ℃. Under these conditions, REE is successfully and efficiently extracted and separated with zinc and aluminum, which revealed a potential application for REE separation and purification from electronic waste.