Equipments that mainly use current and electromagnetic fields to work are called electronic equipment; discarded electronic equipment is classified as electronic waste. E-waste mainly includes discarded products from household appliances such as refrigerators, air conditioners, washing machines, and televisions, and communication electronic products such as computers. Electronic waste is commonly known as "e-waste".
There are many types of electronic waste, which can be roughly divided into two categories: one is waste electronic products that contain relatively simple materials and are less harmful to the environment.
Such as refrigerators, washing machines, air conditioners and other household appliances, as well as medical and scientific research appliances, etc. The disassembly and processing of such products are relatively simple; the other type contains relatively complex materials that are harmful to the environment. Relatively large waste electronic products, such as lead in picture tubes of computers and televisions, arsenic, mercury and other harmful substances contained in computer components. The raw materials of mobile phones contain arsenic, cadmium, lead and a variety of other long-lasting and bioaccumulative toxic substances.
Comprehensive processing of electronic waste through manual disassembly and mechanical disassembly and sorting will not only protect the natural environment, but also enable the recycling and reuse of certain resources to reduce the cost of component manufacturing. Purpose.
[Edit this paragraph] Classification of electronic waste
Electronic equipment actually includes two parts: electrical appliances and electronic appliances. Among them, household appliances are the main source of electronic waste. , is the unity of the above two parts. At present, there are hundreds of types of household appliances in the world with tens of thousands of styles and specifications, but their classification has not yet been unified in all countries around the world.
For example, the United States basically classifies household electrical appliances by complexity and size; Germany and France also classify them by size; and Japan classifies them by use bundle. In my country, they are basically classified according to their uses and are generally divided into the following 14 categories.
(1) Refrigeration appliances such as refrigerators, freezers, cold drink machines, ice machines, ice cream machines, etc.
(2) Air conditioning equipment such as air conditioners, electric fans, dehumidifiers, humidifiers, constant temperature and humidity machines, etc.
(3) Heating appliances such as space heaters, panel electric heaters, far-infrared electric heaters, electric blankets, foot warmers, etc.
(4) Kitchen appliances such as electric rice cookers, electric woks, electric frying pans, electric fryers, electric hot pots, electric steamers, electric hot pots, electric ovens, sandwich ovens, toasters, Electric oven, toaster, household magnetic water heater, household water purifier, oil fume filter, can opener, electric kettle, electric coffee pot, electric stove, microwave oven, induction stove, electric cutter, dishwasher, blender, Juice machines, peeling machines, twisting machines, mixers, forest water treatment machines, food preservers and tenderizers, etc.
(5) Cleaning equipment such as washing machines, dryers, vacuum cleaners, floor waxers, waxing polishers, window cleaners, showers, etc.
(6) Hairdressing equipment such as hair dryers, electric clippers, electric shavers, multi-purpose hairdressers, hair dryers, shavers, etc.
(7) Ironing appliances such as ordinary electric irons, temperature-adjustable irons, spray irons, jet irons, ironing machines, ironing presses, etc.
(8) Electroacoustic equipment such as radios, tape recorders, record players, amplifiers, walkie-talkies, digital records and record players, speakers, and stereo combination audio equipment.
(9) Video equipment such as televisions, video recorders, cameras, CDs, VCDs, DVDs, etc.
(10) Entertainment equipment such as electronic toys, electric toys, electronic game consoles, electronic musical instruments, fishing equipment, musical doorbells, etc.
(11) Health care appliances such as air negative ion generators, alkali ion decomposers, massagers, hypnotics, pulse therapy devices, magnetic therapy machines, far-infrared health care devices, electric toothbrushes, oral cleaners, hearing aids , electromoxibustion device, hot compress device, etc.
(12) Lighting fixtures such as chandeliers and ceiling lamps. Wall lamps, floor lamps, table lamps, spotlights and other new lamps, etc.
(13) Other appliances such as timers, program controller electronics, electric sewing machines, electric bicycles, electronic watches, electronic clocks, electronic door locks, calculators, translators, multimeters, electric meters, glue this appliance.
(14) Computers and communication equipment such as home computers, various mobile phones, pagers, telephones, etc.
[Edit this paragraph] The hazards and profit highlights of electronic waste
The advent of the information age has led to the rapid development of the electronics industry. With the rapid development of the electronics industry, electronic waste pollution is inevitably before us. Electronic waste, commonly known as "e-waste", mainly includes various electronic and electrical products such as computers, communication equipment, televisions, refrigerators, washing machines, etc. that are discarded after use.
The electronic information technology industry has become one of the fastest growing industries in my country, and the resulting electronic waste has also grown rapidly. The next 10 to 20 years will be a new peak in the growth of electronic waste. Waste The disposal and recycling of waste such as computer motherboards (PBC) and circuit boards (PWC) have become an urgent topic for research.
Electronic and electrical products are one of the fastest growing products in the 20th century. According to statistics, the number of TV sets in my country has reached 350 million, and the number of refrigerators and washing machines has reached 130 million and 170 million respectively. Moreover, with the development and innovation of science and technology, electronic products are updated faster and faster, and the service life of electronic products will be shortened accordingly, which will cause the amount of electronic waste to grow linearly.
According to relevant data, in the future, at least 5 million TV sets, 4 million refrigerators, and 5 million washing machines will be scrapped in our country every year. There will also be 5 million computers and tens of millions of mobile phones every year. Entering the elimination period. In 2002 alone, my country eliminated more than 4 million TV sets, more than 5 million washing machines, more than 5 million refrigerators, more than 6 million computers and 30 million mobile phones.
In the United States, 100 million old computers have been shelved, and it is expected that 150 million computers will be eliminated in the next ten years. A market sales survey of electronic products in Western Europe showed that in 2002, the total consumption of various electronic products was approximately 7 million tons, and the total amount of electronic waste was approximately 4 million tons, accounting for 2% of the entire European waste stream. ~3%. "American Newsweek" also reported that the discarded computer floppy disks from all over the world can be added together to form a 100-story "skyscraper" every 20 minutes.
Currently, electronic waste increases by 16% to 28% every five years, which is three times faster than the growth rate of total waste. Electronic waste is becoming a new source of hazardous waste pollution.
Electronic waste is a collection of poisons. For example, a 15-inch CRT computer monitor contains harmful substances such as cadmium, mercury, hexavalent chromium, polyvinyl chloride plastic and brominated flame retardants. Computer batteries and switches contain chromium compounds and mercury. Computer components also contain Arsenic, mercury and many other harmful substances; televisions, refrigerators, mobile phones and other electronic products also contain lead, chromium, mercury and other heavy metals; laser printers and copiers contain toner, etc. If used electronic products are discarded as general garbage into wilderness or landfill areas, the heavy metals such as lead contained in them will penetrate and pollute the soil and water quality, and circulate through the food chain of plants, animals and humans, eventually causing poisoning incidents; if Burning it will release a large amount of harmful gases such as dioxins, threatening human health. The "Guiyu phenomenon" is a living example.
Using physical methods to crush, dissociate and sort municipal solid waste has the characteristics of low investment and low environmental pollution. It is the current development trend of electronic waste treatment.
In fact, electronic waste contains many recyclable non-ferrous metals, ferrous metals, glass and other substances. Strictly speaking. These e-waste should not be called e-waste, but used electronic goods. Research and analysis results show that 286lb of copper, 11b of gold, and 441b of tin can be separated from 1 ton of randomly collected electronic boards, of which only 11b of gold is worth US$6,000 (1lb=0.45359kg). It can be said that "e-waste" contains major business opportunities. If the precious metals such as gold, silver, copper, tin, chromium, platinum, and palladium contained in "e-waste" are "removed", it will be an immeasurable sum. wealth. . For example, components such as central processing units, radiators, and hard drives in used computers are rich in precious metals such as copper, silver, gold, and aluminum; computer casings, power cords, keyboards, and mice are also rich in copper and plastic; components of air conditioners and refrigerators are also rich in copper, silver, gold, aluminum, and other precious metals. Shells and refrigeration systems contain relatively simple iron, aluminum, copper, and plastic components; other heating appliances, cleaning appliances, kitchen appliances, cosmetic appliances, and ironing appliances are also rich in large amounts of iron, plastic, etc.
Japan's Yokohama Metal Company analyzed the components of scrapped mobile phones and found that on average, every 100 grams of mobile phone body contains 14 grams of copper, 0.19 grams of silver, 0.03 grams of gold and 0.01 grams of palladium; in addition, metallic lithium can be recovered from mobile phone lithium batteries. The company has achieved considerable economic benefits by recycling a variety of precious metals from scrapped mobile phones.
The metals contained in electronic waste, especially precious metals, are dozens or even hundreds of times higher in grade than natural mineral deposits, and the recycling cost is generally lower than mining natural mineral deposits.
For example, 100g of gold can be extracted from 1 ton of old mobile phone waste batteries, while ordinary gold-containing ore can only extract 6g per ton, or more than a few dozen grams. It can be said that old mobile phones are a A very high grade gold ore. In printed circuit boards, the most common metal is copper, in addition to gold, aluminum, nickel, lead, silicon, etc., many of which are rare metals. Statistics show that the gold content in every ton of waste circuit boards reaches about 1,000g. With the improvement of technology level, 300g of gold can now be extracted from each ton of waste circuit boards, with a market price of about 30,000 yuan. The U.S. Environmental Protection Agency has confirmed that using scrap steel recovered from scrap household appliances instead of new steel obtained through mining, transportation, and smelting can reduce mining waste by 97%, reduce air pollution by 86%, water pollution by 76%, and reduce water pollution by 40%. Water consumption, saving 90% of raw materials, 74% of energy, and the performance of scrap steel and new steel are basically the same.