How is the economic benefit of recycling and utilizing recycled resources? In recent years, to encourage resource recycling, the country has successively introduced and implemented a series of policies. Simultaneously, with the continuous advancement in the battle against pollution prevention and control and the increasing intensity of environmental supervision, the total amount and value of recycled resources in China have shown rapid growth. According to incomplete statistics, nearly 100 million tons of recyclable resources are available in China each year, valued at over 2 trillion yuan, including over 40 million tons of scrap steel, over 30 million tons of scrap paper, over 5 million tons of scrap non-ferrous metals, 6 million tons of scrap plastic, over 50 million tires, and over 10 million tons of other scrap materials. Moreover, in recent years, China has imported over 20 million tons of various recycled resources annually. Including the waste materials self-collected and used by industrial and mining enterprises, the value of recycled resources in China could reach over 4 trillion yuan each year.
The recycling industry differs from other traditional industries, as it must not only achieve economic benefits but also consider environmental and social benefits. It is an integrated project involving economics, technology, and social management. We should learn from the advanced experience of developed countries, formulate policies and measures to encourage technological innovation and construction investment, and match strict and scientific social management methods. This will make the recycling and utilization of renewable resources a conscious action of enterprises, government agencies, groups, and all citizens, jointly creating a beautiful world of economic prosperity, a pleasant environment, and harmonious coexistence between humans and resources!
1. Copper Alloy: Refers to pure copper, including varieties such as oxygen-free copper, copper, phosphorus deoxygenated copper, and silver copper.
2. Brass: Refers to an alloy based on copper and zinc, which can be further divided into simple brass and complex brass. Among the complex brass, the third component is named for the alloy, such as nickel brass, silicon brass, etc.
3. Bronze: Refers to copper-based alloys excluding copper-nickel, copper-zinc alloys, mainly including tin bronze, aluminum bronze, and special bronze (also known as high-copper alloys).
4. Beryllium Copper: Refers to copper-nickel alloy.
1. Power Transmission: Large quantities of high-conductivity copper are required for power transmission, primarily used in power cables, busbars, transformers, switches, connectors, and junctions.
2. Electric Motor Manufacturing: In the manufacturing of electric motors, high-conductivity and high-strength copper alloys are widely used. The main copper components include stators, rotors, and shaft ends.
3. Communication Cables: Since the 1980s, due to the advantages of fiber optic cables such as high current capacity, they have continuously replaced copper cables in communication trunk lines and rapidly gained widespread application. However, converting electrical energy into light energy and the lines that deliver to the users still require a large amount of copper. With the development of the communication industry, people's reliance on communication is increasing, and the demand for both fiber optic cables and copper wires will continue to rise.
4. Residential electrical wiring
5. Electron Vacuum Devices: Electron vacuum devices primarily include high-frequency and ultra-high-frequency tubes, waveguides, magnetrons, etc., which require high-purity oxygen-free copper and dispersion-strengthened oxygen-free copper.
6. Printed Circuit Boards: Copper printed circuit boards are surface-mounted on a substrate of plastic with copper foil. The circuit layout is photographically transferred onto the copper surface. Excess material is then etched away, leaving the interconnected circuits. Holes are punched at the external connection points on the printed circuit board, where terminal ends of discrete components or other parts are inserted and soldered in place, completing the assembly of the full circuit.
7. Integrated Circuit
8. Wireframe: Copper alloys offer low cost, high strength, conductivity, and thermal conductivity, excellent workability, solderability, and corrosion resistance. Through alloying, their properties can be controlled over a wide range, making them well-suited to meet the performance requirements of wireframes. They have become an important material for wireframes and are one of the most used materials for copper in microelectronic devices.
9. Energy Industry: The utilization of solar energy also requires a significant amount of copper piping. For instance, a hotel pool near London, UK, equipped with a solar heater, can maintain water temperatures between 18~24°C during summer. The solar heater contains 784 pounds (3,56 kg) of copper piping.
10. Petrochemical Industry: Copper and many copper alloys exhibit excellent corrosion resistance in solutions, non-oxidizing acids (such as acetic acid, citric acid, fatty acids, lactic acid, oxalic acid, etc.), various alkalis excluding ammonia, and non-oxidizing organic compounds (such as oils, phenols, alcohols, etc.). Therefore, they are widely used in the petrochemical industry for manufacturing various equipment such as containers, piping systems, filters, pumps, and valves that come into contact with corrosive media. They are also utilized for their thermal conductivity in the production of evaporators, heat exchangers, and condensers. Due to copper's good ductility, it is particularly suitable for manufacturing complexly structured heat exchangers in modern chemical industries where copper piping is intricately woven. Additionally, bronze is used to produce tools in oil refining plants; its inherent non-sparking property during impact helps prevent fires.
11. Ocean Industry: Oceans cover over 70% of the Earth's surface area, and the rational development and utilization of ocean resources are increasingly valued. Seawater contains chloride ions that are easily corrosive, making many engineering metals such as steel, aluminum, and even stainless steel susceptible to corrosion. Moreover, marine biofouling can form on the surfaces of these materials, as well as on non-metals like wood and glass. Copper stands out, not only being resistant to seawater corrosion but also having bactericidal properties of the copper ions dissolved in water, which can prevent marine biofouling. Therefore, copper and copper alloys are crucial materials in the ocean industry and are widely used in desalination plants, offshore oil and gas platforms, and other coastal and underwater facilities. This includes piping systems, pumps, and valves used in desalination processes, equipment on oil and gas platforms such as bolts for splash zones and underwater use, drilling tools, anti-biofouling covers, pump valves, and piping systems, etc. The application of copper and copper alloys in ships will be discussed in a later section.
12. Vessels: Due to their excellent resistance to seawater corrosion, many copper alloys, such as aluminum bronze, manganese bronze, aluminum brass, gunmetal (tin-zinc bronze), white brass, and nickel copper alloys (Monel alloys), have become standard materials for shipbuilding. Generally, copper and copper alloys account for 2% to 3% of the gross weight of merchant ships. Most large merchant ship propellers are made of aluminum bronze or brass. The propellers of large ships weigh between 20 to 25 tons each. The propellers of the Queen Elizabeth and Queen Mary weigh up to 35 tons each.
13. Automotive: Copper usage for vehicles ranges from 10 to 21 kg per car, varying with the type and size. For compact cars, it accounts for approximately 6 to 9% of their total weight. Copper and copper alloys are primarily used in radiators, brake system piping, hydraulic units, gears, bearings, brake pads, distribution and electrical systems, washers, and various connectors, accessories, and trimmings. The radiator is the component that uses the most copper. Modern tube-fin radiators are made by welding brass strips into radiator tubes and bending thin copper strips into fins.
14. Railways: The electrification of railways requires a significant amount of copper and copper alloys. Over 2 tons of special-shaped copper wire are needed per kilometer of overhead conductors. To enhance its strength, a small amount of copper (about 1%) or silver (about of%) is often added. Additionally, the motors, rectifiers, and control, braking, electrical, and signaling systems on trains all rely on copper and copper alloys to function.
15. Planes: Copper is indispensable for the navigation of aircraft. For instance, copper materials are used in the wiring, hydraulic, cooling, and pneumatic systems of planes. Aluminum bronze tubes are employed for the bearing retainers and landing gear bearings, navigational instruments utilize antimagnetic copper alloys, and many instruments incorporate copper elastic elements, etc.
16. Mechanical Engineering: Copper components can be found in nearly all types of machinery. Apart from the extensive use of copper in motors, circuits, hydraulic and pneumatic systems, and control systems, there are also numerous transmission and fastening parts made from brass and bronze, such as gears, worm gears, worm shafts, connectors, fasteners, twist elements, screws, and nuts, which are widely used.
17. Metallurgical Equipment: The metallurgical industry is a major consumer of electrical power, often referred to as "the electric." In the construction of metallurgical plants, it is typically necessary to have a massive transmission and distribution system powered by copper, along with electric power operation equipment. In fire metallurgy, continuous casting technology has taken a leading role, with the key component, the crystallizer, mostly made of high-strength and high thermal conductivity copper alloys like chromium copper and silver copper. In electro-metallurgy, vacuum arc furnaces and electric arc furnace crucibles are made of copper tubing, while various induction heating coils are wound from copper tubing or special-shaped copper tubing, with water cooling inside.
18. Alloy Additives: Copper is an important additive element in alloys such as steel and aluminum. The addition of a small amount of copper (0.2~0.5%) to low-alloy structural steel can enhance its strength and resistance to atmospheric and marine corrosion. Copper added to corrosion-resistant cast iron and stainless steel further improves their corrosion resistance. High-nickel alloys containing about 30% copper are known as high-strength corrosion-resistant "Monel" alloys, widely used in the nuclear industry.
19. Air Conditioners and Refrigeration Units: The temperature control function of air conditioners and refrigeration units is primarily achieved through the evaporation and condensation of the copper tubes in the heat exchanger. The dimensions and heat transfer performance of the heat exchange tubes greatly determine the overall efficiency and miniaturization of the air conditioning and refrigeration systems. These machines utilize copper tubes with high thermal conductivity. By leveraging the excellent machinability of copper, we have developed and produced heat exchange tubes with internal grooves and high fins, which are used in the manufacture of heat exchangers for air conditioners, refrigeration units, chemical engineering, and waste heat recovery systems. This innovative heat exchanger design can achieve a total heat transfer coefficient up to 2-3 times higher than that of standard tubes and 1.2-1.3 times higher than that of standard low-fin tubes. It is currently in use domestically, saving 40% of copper and reducing the volume of the heat exchanger by more than one-third.
20. Watches: Currently produced watches, timers, and devices with watch mechanisms, with most of the working parts made from "watch brass." The alloy contains 1.5-2% lead, has good machinability, and is suitable for mass production.
21. Papermaking: In today's rapidly changing information society, paper consumption is substantial. While paper may seem simple on the surface, the papermaking process is actually quite complex, involving numerous steps and a variety of machinery, such as coolers, evaporators, pulpers, and paper machines. Many components, including various heat exchangers, rollers, striking rods, semi-liquid pumps, and screens, are predominantly made of steel alloys.
22. Printing: Photographic plating is used in the printing process. The polished copper plate is sensitized with light-sensitive lacquer and then photographed to form an image. The sensitized copper plate is then heated to harden the lacquer. To prevent softening from heat, a small amount of silver or arsenic is often added to the copper to increase the softening temperature. Subsequently, the plate is etched to create a printing surface with a pattern of raised and lowered dots. On a typesetting machine, type blocks made of leaded brass are used to arrange the types to create the plate, which is another important use of copper in printing. The type blocks are typically made of leaded brass, and sometimes copper or bronze are also used.
23. Brewing: Copper plays a significant role in the world of beer brewing. It is commonly used for the interior lining of malt vats and fermentation tanks. Some breweries have as many as a dozen large vats, each with a capacity exceeding 20,000 gallons. In fermentation tanks, water-cooled steel pipes are often used for cooling. Steel pipes are also used to heat the beer during brewing with steam and to transport the liquid. For distilling whiskey and other spirits, steel distillation pots are typically used. Whiskey malt requires two distillations, necessitating two large copper distillation pots.
24. Industry: Pure copper is used for all kinds of steam, boiling, and vacuum equipment, as well as a common material for eyeglass frames.
25. Pipe Systems: Copper piping offers aesthetic appeal, durability, ease of installation, safety, fire resistance, and hygiene, making it significantly more cost-effective compared to galvanized steel pipes and plastic pipes.
26. Roofing and Home Renovation: The tradition of using steel sheets for roofs and eaves in Europe is well-established. In Nordic countries, it's even used for wall decorations. Copper is excellent for its resistance to atmospheric corrosion, durability, recyclability, and good workability, allowing it to be shaped into complex forms with its attractive colors. Therefore, it's particularly suitable for home renovations. Its application on the roofs of ancient buildings like churches has a long history, still shining brightly today; and its use in modern large-scale construction, including apartments and residential buildings, is increasingly common. For example, in London, the "Commonwealth Building," a symbol of modern British architectural art, features a complex roof structure made of steel, weighing approximately 25 tons; and the Crystal Palace Sports Center, opened in 1966, boasts a wave-shaped roof made of 60 tons of steel. Statistics show that in Germany, the average annual consumption of copper sheets for roofing per person is 0.8 kg, while in the United States, it's 0.2 kg. Moreover, interior renovations such as door handles, locks, blinds, balusters, lighting fixtures, wall decorations, and kitchenware, all made of steel, are not only durable and hygienic but also add an elegant touch, making them popular among consumers.
27. Statues and Craftworks: No metal in the world is as widely used in the production of various craftworks as steel, which has been enduring and popular from ancient times to the present. In today's urban construction, a multitude of memorials, bells, cauldrons, sculptures, Buddha figures, replicas, and more, all extensively utilize cast copper alloys. Modern musical instruments, such as flutes made of white steel and saxophones made of brass, also require various copper alloys. Exquisite gold-plated and gold/silver replicas, offering great value for their price, also necessitate the use of different copper alloys.
28. Currency: Since the ancestors of humanity began using coins, copper and copper alloys have been used to manufacture them, passed down through generations to the present day. With the development of modern activities benefiting the public such as coin-operated phones, rides, and shopping, the demand for steel in coin production has only increased. In the application of copper coins, besides changing sizes, it is convenient to use different alloy compositions and alter alloy colors to produce and differentiate coins of various denominations. Common types include "silver coins" containing 25% nickel, brass coins with 20% zinc and 1% tin, and "copper" coins containing a small amount of tin (3%) and zinc (1.5%). Worldwide, the production of copper coins consumes thousands of tons of copper annually. Just the Royal Mint in London produces 700 million copper coins each year, requiring approximately 7,000 tons of metal.
29. Mainframe Computers: Information technology is the forefront of high-tech. It relies on the crystallization of modern human wisdom—the tool known as a computer—for processing and handling information that is ever-changing and abundant. The heart of a computer consists of microprocessors (which include the arithmetic and control units) and memory. These basic components (hardware) are large-scale integrated circuits, which are composed of millions of interconnected transistors, resistors, capacitors, and other components on a tiny chip. These integrated circuits are assembled using lead frames and printed circuit boards to function. As seen in the previous chapter "Applications in Electronics Industry," copper and its alloys are not only important materials for lead frames, solder, and printed circuit boards but also play a crucial role in the interconnection of the minute components within integrated circuits.
30. Superconductivity and Low Temperature: Generally, the resistance of materials (except for semiconductors) decreases with the lowering of temperature. When the temperature is reduced to a very low level, the resistance of certain materials can completely disappear, a phenomenon known as superconductivity. The temperature at which superconductivity occurs is referred to as the material's critical superconducting temperature. The discovery of superconductivity has opened up a new realm for the utilization of electricity. Since resistance is zero, a very small voltage can produce an extremely large (theoretically infinite) current, generating immense magnetic fields and forces; or, when current passes through it, there is no voltage drop and no loss of electrical energy. Clearly, its practical applications will bring about significant changes in human production and living, and it has garnered considerable attention.
31. Agricultural and pastoral applications: Compounds of steel are effective bactericidal pesticides for eliminating pests and diseases, controlling all diseases caused by molds or fungi. Besides directly treating seeds with copper dips, copper salt solutions are commonly used in orchards and farmlands. Notable ones include Bordeaux mixture (limed copper solution), named after the French grape-growing region, and Buggundy solution (soda copper solution), as well as other products like Bactocide.
32. High Energy Physics: Unveiling the mysteries of matter structure is a major fundamental scientific issue that scientists have been pursuing. Every step deeper in understanding this issue brings significant impacts to humanity. The current utilization of atomic energy is an example. Modern physics research has found that the building blocks of matter are not molecules and atoms, but quarks and leptons, which are billions of times smaller. The study of these fundamental particles often requires reaction energies hundreds of times higher than those of nuclear reactions, known as high-energy physics. Such high energies are obtained either by accelerating charged particles through long distances in a strong magnetic field to "strike" a fixed target (high-energy) or by colliding two streams of particles moving in opposite directions (collider). To achieve this, steel is used to construct long-distance channels with strong magnetic fields. Additionally, similar structures are needed in controlled thermal nuclear reaction devices. To reduce the temperature rise due to the heating caused by large currents, these magnetic channels are wound from hollow, non-standard copper rods to allow for the passage of a medium for cooling.
