In 2019, the total copper and aluminum conductors used in China were about 6.7 million tons (accounting for more than 60% of the total copper used in China) and 1.9 million tons respectively The total sales value of the wire and cable industry has reached 1.42 trillion yuan. In the large machinery industry, in addition to the automotive industry, ranking 2.

In recent years, new materials, new processes, new technologies, new equipment and new products related to advanced manufacturing of metal conductors have emerged at home and abroad.

The new standards for "recycled copper raw material" (GB/T38471-2019) and "pyrometallurgical refining of high conductivity copper rods for electricians" (NB/T10194-2019) have been promulgated and implemented in 2020. In order to ensure the quality of wire and cable conductor, energy-saving and environmental protection, to make the best use of everything, high-quality and high-cost to create the necessary conditions.

The production of electrical and electronic high-conductivity oxygen-free copper rods (UNSC10100 and C10200) by using recycled copper as raw material on the up-drawing production line is not a myth but a reality.

New Progress has been made in the pretreatment technology for the raw material of regenerated copper enamelled wire. It is of great technical and economic significance to ensure the quality of wire and cable conductors and to supply more raw materials for Non-ferrous metal and painted parts for electricians in the market.

Substantial progress has been made in the industrialization of ultra-high Purity 5N and 6N copper in China. Further improvement of purity and its detection, large-scale adjustment of price, expansion of market and no longer relying on imports are the problems that need to be further studied.

Compared with Ohno continuous casting method in Japan, "CZOCHRALKI" single crystal copper has a high conductivity of 105.6% iacs. It can be used in video/audio cable to improve the signal transmission effect.

Cuprum-silver alloy wire for overhead transmission lines can obtain high-strength and high-conductivity conductors, which can effectively increase the carrying capacity by 12% and the working temperature can reach 150 ° °C, transmission energy loss can be reduced by up to 40% . In this paper, the home-made demonstration production line of high-purity copper-silver wire, bonding wire, precision resistance and 120,000 ton/year regenerative copper raw material pyrometallurgical refining high-conductive low-oxygen copper (FRHC) direct regenerative rod is introduced.

1.High Purity Copper and silver wire foil, bonding wire and precision resistor

Copper Alloys for electrical purposes are developing in the direction of copper alloys for electronic purposes. Our country, adhering to the spirit of "independence and self-reliance, " has launched an attack, and has achieved results, i believe that in the near future will be able to keep up with the rapid development of China's electronic industry needs. Our country has organized the construction of the first ultra-pure Copper Alloy micro-wire and foil demonstration production line, which has all the independent manufacturing capacity from raw materials to finished products.

Technical Difficulties:

Improving the purity of raw material, refining and degassing, strictly controlling the oxygen content, inhibiting the formation of brittle phase at the interface, preventing grain looseness and pore enrichment, ensuring the consistency of line blank and line quality, laying a good foundation for precision machining.

The suitable multi-pass work hardening of ultra-fine wire was found by controlling the AG content properly and stably. With the increase of drawing pass, obvious fibrous tissue was formed and the composite strengthening effect was gradually revealed.

In the copper-silver system, silver can be easily replaced to form a homogeneous solid solution, which makes it difficult to improve its properties. It is necessary to improve the heat treatment process and control each process point precisely so as to achieve continuous precipitation and dispersion distribution of Cu and Ag phases, and then control the properties of the alloy.

2.120000 t/a copper regeneration raw material pyrometallurgical refining high conductivity low oxygen copper (FRHC) direct regeneration rod demonstration production line

With the support of the Ministry of Science and Technology of the People's Republic of China, the demonstration production line of direct regenerative rod making by pyrometallurgical refining of regenerated copper materials passed the inspection and acceptance of the Ministry of Science and Technology in 2014, and immediately became the key promotion project of the Ministry of Science and technology. The utility model can be used for the production of power cables, equipment cables, enamelled wires and bare copper wires, etc. 

At present, "FRHC" has become a general term in international standards. It was first incorporated into the European standard, followed by the second line of YS/T793-2012 and the third line of American standard. The direct rod-making process, equipment, technology and product quality of pyrometallurgical refining of recycled copper raw materials in China have entered the international advanced level. Green environmental protection requirements have also met the requirements of national standards.

What's new with the line:

The first high-end equipment production line in China has been developed, which is not only suitable for direct recycling of scrap copper to produce copper poles for electricians, but also suitable for producing copper poles for electricians with electrolytic copper

The production line integrates the latest technology, equipment, auxiliary facilities and automatic control at home and abroad

The automatic level control of continuous casting has been realized for the first time in several decades in China, thus reducing the Labor intensity, stabilizing the product quality and filling the domestic blank

The production line realizes the real-time and on-line quality control, ensures the consistency of stable production and product quality, and improves the "rolling, drawing and annealing" of the product

Using advanced and high-efficiency gas purification technology and combustion system to realize PLC interface control, it has the remarkable characteristics of strengthening smelting, high-efficiency impurity removal, green environmental protection and low energy consumption, the natural gas consumption index is about 75-95m3/T copper Rod. Compared with traditional scrap copper

The new type of two-roll cantilever continuous rolling mill is innovated by integration. The stand can be driven separately to realize the fast and accurate adjustment of rolling pass, and the elongation of the whole rolling system can be adjusted It solves the problem of oil-emulsion mixing for several decades in our country, prolongs the service life of Roller, reduces the production cost and improves the production efficiency

Accurate temperature control and oxygen control have been realized and the product quality has been stabilized

The automatic control of the flow, temperature and pressure of the liquid (cooling water, emulsion, lubricating oil, cleaning liquid) and the filtration of the emulsion are solved

Using the international advanced control system, we have realized a series of functions such as Interlock start-stop, loop automatic regulation, alarm, record and so on.

The new progress of FRHC copper rod production in pretreatment

"pyrolytic analysis" , also known as dry distillation, pretreatment in the regeneration of copper enameled wire stripping, tin or lead-tin Alloy in copper and aluminum on the application.

PRINCIPLE: "pyrolysis" , also known as dry distillation, is the basic thermochemical process by which organic matter is heated in isolation from air or partially burned in the presence of a small amount of oxygen to be converted into useful fuels or chemical feedstocks. "melting out" means that the liquid phase is separated from the solid phase in the melting state or in the slow cooling process due to the different melting points of various substances.

Technical Highlights:

The pyrolyzed oil and gas can be discharged in a closed system (no synthetic dioxin in the oxygen-deficient or reducing atmosphere) , and the pyrolyzed oil and gas can be condensed and purified and then burned at high temperature of 800 °c-900 °C, effectively eliminate the presence of dioxin (Dioxin Burns completely at 800 °C for 26 seconds and completely at 1000 °C for 1 second.

The oil and gas can be used as fuel for its own production, thereby maximizing energy conservation.

The resources can be fully utilized as a result of avoiding the oxidation loss of copper, and the metal recovery rate is more than 98% . The application of "pyrolytic analysis" technology in pretreatment is a new technology of independent innovation in our country, and has realized industrialization and practical application.

4.New Applications

(1) Winding wire applications: Requirements: High Strength, low resistance, good temperature resistance, diameter stability. Application: small relay, micro motor, ignition coil, micro inductor, telecommunication instrument. The cable runs from the shallow sea to the open sea

(2) DEEP-SEA APPLICATIONS: Requirements: High Strength, Long Distance, low loss, anti-interference, fatigue and so on. USES: Submarine Long Optical Cable, offshore wind power, electric composite cable, offshore oil production comprehensive (cable) and so on.

(3)Medical Applications: Requirements: non-toxic, anti-interference, anti-fatigue, extra fine, high flexibility, etc. . USES: Cardiac Cable and lead wire, brain electrode and electrode sheet, high frequency electric knife, doppler probe, endoscope, etc. 

(4)Electronic applications: Requirements: ultra-fine, ultra-thin, high conductivity, high heat resistance, stress relaxation, wear resistance. USES: connector, connecting wire, bonding wire, high precision resistance, shield plate, heat sink plate, etc. 

(5)APPLICATION OF INDUSTRIAL ROBOT CABLE: Requirements: Soft, bending resistance, tensile, waterproof, oil, acid and alkali resistance, UV resistance, fatigue resistance, wear resistance. USES: Automotive Production Lines, logistics handling, spraying, welding and high-temperature irradiation operations.

Conclusion: The Independent Innovation Research on high conductivity, high strength, high heat resistance, ultra-fine copper-silver alloy wire and foil has been successfully carried out and mass-production has been realized, it fills the gap in the application of Copper Alloy Wire and cable in integrated circuit, aerospace, ocean engineering and so on, and is the first in China.

Production of high conductive oxygen-free copper (UNSC10100 and C10200) rods on the up-drawing production line with reclaimed copper materials is not a myth but a reality. GB/T38471-2019 standard for recycled copper raw materials and NB/T10194-2019 standard for pyrometallurgical refining of high conductivity (FRHC) copper rods for electricians were implemented in 2020, it is of great technical and economic significance. The pretreatment of regenerated copper enameled wire by chemical method and retorting method is of great significance to the green production and the improvement of the quality of regenerated copper rod and wire, we should deepen the verification in the popularization and application in order to make both the supplier and the demander obtain better technical and economic results.

Substantial progress has been made in the industrialization of domestic 5N and 6N copper. It is necessary to expand the application of 8N copper in top-notch industries in the future, and to step forward to 8N copper, which has already been commercialized in the foreign sound market, and to solve the problem of analysis and certification of 8N copper. 

Source: SMM coloured information