How is the economic benefit of recycling and utilizing renewable resources? In recent years, with the state's encouragement of resource recycling through the successive introduction and implementation of various policies, and with the continuous advancement in the battle against pollution prevention and control as well as the increasing intensity of environmental supervision, China's total amount and value of renewable resource recycling have shown rapid growth. According to incomplete statistics, nearly 100 million tons of renewable resources are recyclable 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 scrap tires, and over 10 million tons of other scrap materials. Moreover, in recent years, China has imported over 20 million tons of various renewable resources annually. Including the waste materials collected and used by industrial and mining enterprises, the annual value of renewable resource recycling and utilization in China can reach over 4 trillion yuan.
The再生resource industry differs from other traditional industries; in addition to achieving economic benefits, it must also consider environmental and social benefits. It is an integrated project involving economics, technology, and social management. We should draw on advanced experience from developed countries to formulate policies and measures that encourage technological innovation and construction investment, complemented by rigorous and scientific social management methods. This will make the recycling and reuse of resources a conscious effort of enterprises, agencies, groups, and all citizens, collectively creating a world of economic prosperity, beautiful environments, and harmonious coexistence between humans and resources!
1. Copper: Refers to pure copper, mainly including oxygen-free copper, red copper, phosphorus deoxidized 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, nickel brass and silicon brass, named after the third component, are particularly notable.
3. Bronze: Refers to copper-based alloys other than copper-nickel and copper-zinc alloys, mainly including tin bronze, aluminum bronze, and special bronze (also known as high copper alloys).
4. White Brass: Refers to copper-nickel alloy.
1. Power Transmission: Large quantities of high-conductivity copper are consumed in power transmission, primarily used in power cables, busbars, transformers, switches, connectors, and terminal blocks, etc.
2. Electric Machine Manufacturing: In electric machine manufacturing, high-conductivity and high-strength copper alloys are widely used. The main copper components include stators, rotors, and shaft ends, etc.
3. Communication Cables: Since the 1980s, fiber optic cables have been rapidly replacing copper cables in communication trunk lines due to their high capacity and other advantages. However, converting electrical energy into light energy and transmitting it to the end-users still requires a significant amount of copper. As the communication industry grows, the reliance on communication increases, 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 made by adhering copper foil to a plastic substrate as the base. The circuit layout is then photochemically transferred onto the copper surface. Excess material is removed through etching, leaving the interconnected circuit paths. Holes are punched in the printed circuit board at points for external connections, and the terminals of discrete components or other parts are inserted and soldered into place, completing the assembly of the entire circuit.
Integrated Circuit
8. Wire Frame: Copper alloys offer low cost, high strength, conductivity, and thermal conductivity, excellent processing properties, 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 wire frames. They have become an important material for wire frames and are currently the most widely used copper material 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. This 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 except ammonia, and non-oxidizing organic compounds (such as oils, phenols, alcohols, etc.). Therefore, they are extensively used in the petrochemical industry for manufacturing various equipment, including containers, pipeline 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 plasticity, it is particularly suitable for manufacturing complexly structured heat exchangers with intertwined copper pipes in modern chemical industries. Additionally, bronze is used to produce tools in oil refining factories; it is non-sparking upon impact, preventing the occurrence of fires.
11. Ocean Industry: With the ocean covering over 70% of the Earth's surface, the rational development and utilization of marine resources are increasingly valued. Seawater contains chloride ions that are corrosive, making many engineering metals like steel, aluminum, and even stainless steel susceptible to corrosion. Additionally, marine organisms can foul the surfaces of these materials, as well as non-metals like wood and glass. Copper, however, stands out, not only being resistant to seawater corrosion but also having antibacterial properties of copper ions in solution, which can prevent marine biofouling. Therefore, copper and its alloys are crucial materials in the ocean industry, 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 and drilling tools for splash zones and underwater use, anti-biofouling covers, pump valves, and piping systems, among others. The application of copper and copper alloys in ships will be discussed in the following section.
12. Ships: Due to their excellent resistance to sea water corrosion, many copper alloys, such as aluminum bronze, manganese bronze, aluminum brass, gun metal (tin-zinc bronze), white copper, and nickel copper alloys (Monel alloys), have become standard materials for shipbuilding. Generally, copper and copper alloys account for 2% to 3% of the self-weight of merchant ships. Most large merchant ships' propellers are made of aluminum bronze or brass. Each propeller for a large ship weighs 20 to 25 tons. The propellers of the Queen Elizabeth and Queen Mary each weigh up to 35 tons.
13. Automotive: Copper used in cars ranges from 10 to 21 kilograms per vehicle, varying with the type and size of the car, accounting for approximately 6 to 9% of the car's weight in compact cars. Copper and copper alloys are primarily used in radiators, brake system piping, hydraulic equipment, gears, bearings, brake pads, electrical and power distribution systems, washers, and various fittings, 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 greatly increases the demand for copper and copper alloys. Over two tons of special-shaped copper wire are required per kilometer of overhead conductor. To enhance its strength, a small amount of copper (about 1%) or silver (about of%) is often added. Moreover, the electric motors, rectifiers, and control, braking, electrical, and signaling systems on trains all rely on copper and copper alloys to function.
15. Planes: The navigation of planes also relies on copper. For instance, copper materials are used in wiring, hydraulics, cooling, and pneumatic systems within the plane. Aluminum bronze tubes are used for bearing retainers and landing gear bearings, navigational instruments employ anti-magnetic copper alloys, and many instruments utilize 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 systems, pneumatic systems, and control systems, there are numerous copper alloys, like brass and bronze, used for transmission and fastening parts, such as gears, worm gears, worms, connectors, fasteners, twists, screws, nuts, etc. They are ubiquitous.
17. Metallurgical Equipment: The metallurgical industry is a major consumer of electrical power, often referred to as the "power" industry. In the construction of metallurgical plants, it is typically necessary to have a large-scale transmission and distribution system, as well as power operation equipment, that rely on copper for operation. In fire metallurgy, continuous casting technology has become dominant, with key components such as crystallizers often made of high-strength and high-conductive copper alloys like chrome copper and silver copper. In electro-metallurgy, vacuum arc furnaces and electroslag furnace water-cooled crucibles are manufactured using copper tubing. Various induction heating coils are wound from copper tubes or special-shaped copper tubes, with water circulation for cooling.
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. Adding copper to corrosion-resistant cast iron and stainless steel can further improve their corrosion resistance. High-nickel alloys containing about 30% copper are known for their high strength and corrosion resistance, referred to as "Monel" alloys, and are widely used in the nuclear industry.
19. Air Conditioners and Refrigeration Machines: The temperature control function of air conditioners and refrigeration machines is primarily achieved through the evaporation and condensation of copper tubes in the heat exchangers. The size and thermal conductivity of the heat exchange tubes greatly determine the overall efficiency and miniaturization of the air conditioning and refrigeration systems. High thermal conductivity non-standard copper tubes are used in these machines. By utilizing the excellent machinability of copper, newly developed and produced heat exchange tubes with internal grooves and high fins have been created, used for the heat exchangers in air conditioners, refrigeration machines, chemical industry, and waste heat recovery systems. These tubes can increase the total thermal conductivity coefficient of the new heat exchangers up to 2-3 times that of ordinary tubes and 1.2-1.3 times that of ordinary low-fin tubes. They are already in use domestically, saving 40% of copper and reducing the volume of the heat exchangers by over one-third.
20. Watches: The watches, timers, and devices with clock mechanisms currently produced, the majority of which are manufactured using "clockcase brass." The alloy contains 1.5-2% lead, boasts good machinability, and is suitable for mass production.
21. Papermaking: In today's rapidly changing information society, there is a high demand for paper consumption. Although paper appears simple on the surface, the papermaking process is actually quite complex, involving numerous steps and a variety of machinery, such as coolers, evaporators, pulpers, paper machines, and more. Many of the components, such as various heat exchanger tubes, roller wheels, striking bars, semi-liquid pumps, and meshes, are mostly made of steel alloys.
22. Printing: Photographic plating is used in the printing process with copper plates. The polished surface of the copper plate is sensitized with light-sensitive lacquer and then a photographic image is formed on it. The sensitized copper plate needs to be 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. Next, the plate is etched to create a printing surface with a pattern of raised and recessed dots. On an automatic typesetter, type molds made of leaded brass are used to arrange the characters to form the plate, which is another important application of copper in printing. The type molds 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 as the inner lining of malthouses and fermentation tanks. Some breweries have as many as a dozen large barrels, each exceeding 20,000 gallons in capacity. In fermentation vats, water-cooled steel pipes are often used for cooling. Steel pipes are also used to heat the brew with steam and to transfer the liquid through them. For distilling whiskey and other spirits, steel stills are typically employed. Whiskey malt needs to be distilled twice, requiring two large copper stills.
24. Industrial: Pure copper is used for all types of steam, boiling, and vacuum equipment. Copper alloys are also commonly used for eyeglass frames, etc.
25. Pipe Systems: Copper piping offers numerous advantages such as 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: It is traditional in Europe to use steel for roofs and eaves, even for decorative wall finishes in Scandinavian countries. Copper boasts excellent resistance to atmospheric corrosion, durability, recyclability, and good workability, allowing it to be easily shaped into complex designs, with its attractive colors making it ideal for home renovations. Its application on the roofs of ancient buildings like churches has a long history and still shines brightly today; it's also increasingly used in the construction of modern large buildings, including apartments and residential complexes. For instance, in London, the "Commonwealth Institute," a landmark of modern British architectural art, has a complex steel roof weighing approximately 25 tons; the Crystal Palace sports center, which opened in 1966, features a steel roof weighing 60 tons in a wavy design, etc. Statistics show that in Germany, the average annual consumption of copper roofing per person is 0.8 kilograms, and in the U.S., it's 0.2 kilograms. Moreover, for interior home renovations, such as door handles, locks, blinds, railings, lighting fixtures, wall decorations, and kitchenware, using steel products is not only durable and hygienic for disinfection but also adds an elegant touch, making them highly favored by people.
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 throughout history. In today's urban construction, a multitude of memorials, bells, cauldrons, sculptures, Buddha figures, replicas, and more are extensively made with cast copper alloys. Modern musical instruments, such as flutes made of white steel and saxophones made of brass, also require various copper alloys. Exquisite, affordable gold-plated and gold/silver imitation jewelry also necessitates the use of different copper alloys.
Coins: Since the ancestors of humanity began using coins, copper and copper alloys have been used to manufacture them, passed down through generations and continuing to this day. With the development of modern activities like automatic coin-operated phones, public transportation, and shopping for the public, the demand for coin-making steel 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 various denominations. Common types include "silver" coins containing 25% nickel, brass coins with 20% zinc and 1% tin, and "copper" coins with 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. Chinese Computer: Information technology is the pioneer of high technology. It relies on the crystallization of modern human wisdom—the computer tool—to process and handle the ever-changing and immense amount of information. The heart of the computer is composed of the microprocessor (including the arithmetic and control units) and memory. These basic components (hardware) are large-scale integrated circuits, which are tiny chips with millions of interconnected transistors, resistors, capacitors, and other elements, enabling rapid numerical computations, logical operations, and massive information storage. These integrated circuit chips need to be assembled with lead frames and printed circuit boards to function. As seen in the previous chapter "Applications in the Electronics Industry," copper and its alloys are not only important materials for lead frames, solder, and printed circuit boards; they also play a crucial role in the interconnection of the tiny components of integrated circuits.
30. Superconductivity and Low Temperature: Generally, the resistance of materials (except for semiconductors) decreases with decreasing temperature. When the temperature is lowered significantly, the resistance of certain materials can completely vanish, a phenomenon known as superconductivity. The temperature at which superconductivity occurs is referred to as the superconducting critical temperature of the material. 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 flows through it, there is no voltage drop and no energy loss. Clearly, its practical applications will bring about significant changes in human production and living, and it has garnered considerable attention.
31. Applications in Agriculture and Animal Husbandry: Steel compounds 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 mixtures are commonly used in orchards and farmlands. Notable ones include Bordeaux mixture (limed copper solution), named after the French vineyards, and Buggundy mixture (soda copper solution), as well as others like Zinol.
32. High Energy Physics: Unveiling the mysteries of matter structure is a major fundamental issue that scientists have been striving to solve. Every step deeper in understanding this issue brings significant impacts to humanity. The current utilization of atomic energy is one such example. Modern physics research has already discovered that the smallest units of matter are not molecules and atoms, but quarks and leptons, which are billions of times smaller. Now, research on these fundamental particles often requires reaction energies hundreds of times higher than those in nuclear reactions, known as high energy physics. Such high energies are obtained either by accelerating charged particles over long distances in a strong magnetic field and "colliding" them against a fixed target (high energy) or by colliding two streams of particles moving in opposite directions (colliders). To achieve this, steel is used to construct long-distance strong magnetic field channels. Additionally, similar structures are needed in controlled thermal nuclear reaction devices. To reduce the temperature rise caused by the heating from large currents, these magnetic channels are wound from hollow, non-standard copper rods to allow for medium circulation and cooling.
