Recycling of waste electronic equipment resources has become a hot spot
Today's world is becoming more and more technologically advanced, and a major environmental problem is becoming more prominent. Our old, old and old TVs are often directly landfilled or not properly recycled, causing toxic substances to ooze out, causing atmospheric, soil and water pollution. At the same time, the production of new raw materials to produce new electronic equipment will generate more pollution and emit more carbon dioxide. The Global Electronic Waste Monitoring (GEM) is a joint project of UNU, the International Telecommunication Union and the International Solid Waste Association. Statistics from the project show that in 2016 alone, nearly 45 million tons of e-waste were produced globally.
As consumers frequently change products, the total amount of e-waste continues to increase, and more and more people around the world are beginning to have access to electronic devices. By 2021, the annual increase in e-waste is expected to reach 52.2 million tons. At the same time, most of these electronic wastes are not recycled. According to the Global E-Waste Monitor (GEM), two-thirds of the world's population is subject to e-waste management laws, but only 20% of e-waste is properly recycled. Reuse. About 4% of them are directly thrown into the trash can, and another 76% are either unknown or have poor recycling conditions, which will have a very negative impact on the environment and human health.
However, the value of e-waste as a resource is gradually emerging. Modern electronic products contain a variety of precious metals, including gold, copper, platinum and various rare earth elements (such as lanthanum and cerium). According to the Global Electronic Waste Monitoring (GEM), the total value of all raw materials in e-waste in 2016 is about 55 billion euros (about 440 billion yuan).
Jason Ruff, a professor of chemistry at the University of Edinburgh, said: "All electronic products contain a lot of valuable metals, so we should recycle them because it takes a lot of time to extract them from the ground and separate them from other materials. Human and material resources."
Recycling challenges
In Europe, e-waste is regulated by the Waste Electrical and Electronic Equipment (WEEE) Directive. The directive includes a series of measures to improve the collection, processing and recycling of electronic products after their useful life.
Susanna Baker, head of trade and technology at Tech UK, said that recycling e-waste from consumers remains a formidable challenge. She said: "Many small electronic devices are eventually thrown into the trash. There is a lack of measures to encourage consumers to send these e-wastes to municipal recycling facilities." Associate Professor of Environmental Science at Tsinghua University has been urban mining and e-waste management. Expert in terms. He believes that e-waste recycling is a major obstacle faced by both developed and developing countries. He pointed out that subsidies are crucial to increase the e-waste recycling ratio of retailers and manufacturers.
The total amount of e-waste in China is expected to increase from 1,500 tons in 2020 to 2,840 tons in 2030, making it a much larger source of electronic waste than the United States or the European Union. However, it has been said that China is also becoming a leading country in the mining of electronic waste cities.
Global total electronic waste (unit: million tons)
Frontier position of mining in the city
At present, the Chinese government has subsidized to promote the collection and extraction of electronic waste and its valuable materials. For example, recovering metal from a cathode ray tube (CRT) TV can earn about $13 (about 90 yuan). It has been considered that this is very important to improve the attractiveness of urban mining to Chinese businesses. The subsidy policy means that mining in China's cities is cheaper than raw mining. Professor Zeng, who has been working with Professor Li Jinhui of Tsinghua University and John Matthew of Macquarie University in Australia, predicts that the cost of obtaining the metal needed for a cathode ray tube TV through raw mining is higher than the cost of extracting these metals through urban mining. It is 13 times higher than it is. Research has also shown that for printed circuit boards (PCBs), the cost of raw mining is more than seven times that of urban mining. Currently, electronic waste recycling is mainly done through industrial smelters. For example, the printed circuit board of a notebook computer is crushed and transported to a smelter, and then copper, gold and silver are extracted therefrom. Raff said that the smelter is a high-energy-consuming industry with a high temperature of 2000 degrees Celsius and a large amount of carbon dioxide gas. The difficulty in extracting metals from e-waste is that the materials used in electronic devices are very complex and may contain different metals, glass, plastics and weld metals. Therefore, the factory must physically disassemble the electronic equipment before smelting and extraction, Raf added.
Manufacturers discover market potential
Some international electronics manufacturers have begun to focus on the urban mining industry. Technology giant Dell has used gold recovered from old computer motherboards in new computer motherboards. In addition, Dell worked with a jewelry designer to make earrings and cufflinks from recycled gold. According to research by the agency Trucost, the extracted gold is 99% lower than the environmental impact of traditional gold mining. Dell has promised that the total weight of recycled components in its products will reach 100 million pounds (about 45.36 million kilograms) by 2020. At the same time, Apple has also developed a robot that is responsible for dismantling the iPhone. Among them, the latest version of the Daisy robot can disassemble 200 iPhones per hour and dismantle and classify the recyclable parts. Apple's goal is to completely bid farewell to the original mined material during the manufacturing process. Scholars are also working hard to develop new urban mining processes. For example, a group of chemists at the University of Edinburgh developed a new compound that separates gold from other elements in the phone.
Gold is the most valuable metal in mobile phones. A ton of gold ore contains about 1 to 5 grams of gold, but the gold content of a ton of mobile phones exceeds 300 grams. In fact, about 7% of the global circulation of gold exists in electronic devices (such as the key contacts of circuit boards). The next phase of research is to work with a geoscientist. The latter is interested in developing a biological method for dissolving metals by bacteria, which can be combined with Raf's chemical separation method. In addition, Ralph also hopes to work with engineers to develop a commercial separation process. He said: "We want to make this process more environmentally friendly and replace the traditional smelting process." In addition, people are also working hard to reduce the difficulty of obtaining metal and rare earth data. Industries, research institutes, and geological survey agencies have jointly created an urban mining database. This project, called ProSUM, clarifies the maximum inventory of several specific materials, which allows users to see real-time changes in the EU's e-waste stock. For example, this project will show which metals are used and which are being used. In other words, the goal of this system is to provide decision makers with a factual basis relevant to legislation, helping the academic community to identify research priorities and innovative opportunities for raw material regeneration. At the same time, the University of Cork in Ireland is also launching a project called “RecEOL”, hoping to find a way to make urban mining more “profitable”. The goal of the project is to increase the metal recovery rate of e-waste from 70%-80% to 95%. Researchers say this is also the first technology to recycle critical and specialty metals, such as indium and germanium from printed circuit boards and liquid crystal displays. The study, demonstrated by a pilot plant, is more economically viable and environmentally friendly than existing recycling methods. The academic community has participated in this international project with a number of institutions in the industry, including the Freiburg University of Mining and Metallurgy (Germany), and the waste plastics processor Coolrec BV (Belgium), Mud Hoverton Recycling and Environmental Technology Industrial user companies of this technology such as Ltd. (Germany) and Alumisel SAU (Spain). Tech UK's Baker said: "There has been a lot of academic research on urban mining, but most of them are still in the laboratory stage and have not entered the pilot." She said: "We know the resources of the city mines, just need more Innovations help us 'mining' resources. The challenge to overcome is to find a cost-competitive approach to the exploitation of existing raw materials, while at the same time achieving stable and sufficient resource extraction to ensure the entire process Profitable and predictable. This is the next frontier."