The pretreatment intention of recycling waste wires and cables is mainly to separate waste copper wires from insulation, and there are four main methods:
One is mechanical separation, which can be divided into two types.
1, processing method of roller peeler. This method is suitable for the treatment of waste wires and cables with the same diameter. This kind of equipment already exists in our country. This kind of equipment is selected by Wolfhampton factory in England to strip waste wires and cables, and the effect is very good.
Waste wires and cables are first cut into sections with a length of no more than 300 mm, and then manually sent to a special drum shredder.
The wire and cable in the drum chopper broke and peeled off, and the debris leaked from the screen hole with a diameter of 5 mm at the bottom of the drum blade. The rotating speed of the drum is 3000 rpm, the diameter of the drum is 30 inches, the gap between the drum blades and the surface of the bottom sieve plate is 65438 0.5 mm, the processing capacity of the drum chopper is 65438 0 tons/hour, and the motor power is 30 kW.
The waste leaked from the sieve hole is sent to the silo by belt, and then sent to the shaking table by vibrating feeder for sorting, and finally copper chips, mixture and plastic fibers are obtained. Copper waste can be directly used as raw material for copper smelting or copper sulfate production, and the mixture is returned to the drum chopper for treatment, and plastic fiber can be sold as a product.
Each ton of waste wire and cable can produce 450-550 kilograms of copper sheet and 450-550 kilograms of plastic. It can process 60 tons of materials in one week, producing 30 tons of copper scrap and 30 tons of plastic. Replace the blades every 30 tons of waste cables and wires. The blades are made of high-speed east-west steel.
This process has the following characteristics:
A, copper and plastic in waste wires and cables can be recycled, and the utilization degree is high;
B, the produced copper scrap contains no plastic at all, thus reducing the pollution of plastic to the atmosphere during smelting;
C, simple process, easy mechanization and automation;
The disadvantages of this equipment are high power consumption and fast blade wear during machining.
2, cutting peeling machine processing method. This method is suitable for handling heavy cables and wires, and a factory in Xiangfan, China has been able to produce this equipment.
Second, the low temperature freezing method
U.S. Pat. No.399064 1 proposes to separate the copper in the waste wire from the insulation layer by cryogenic freezing.
The low-temperature freezing method is suitable for handling wires and cables of various specifications. Waste wires and cables are frozen to make the insulation layer brittle, and then the insulation layer is separated from the copper wire by vibration crushing.
Third, chemical stripping method.
In this method, an organic solvent is selected to dissolve the insulation layer of the waste wire, so as to separate the copper wire from the insulation layer. The advantage of this method is that high quality copper wire can be obtained, but the disadvantage is that the solution is difficult to handle and the solvent price is high. The development direction of this skill is to study a useful, useful and cheap solvent.
4. Thermal decomposition method U.S. Pat. No.4,040,865 proposes to burn the insulating layer by thermal decomposition method, and then obtain copper wire.
Waste wires and cables are cut first, and then transported to the pyrolysis chamber by the feeder to participate in pyrolysis. The pyrolyzed copper wire is transported to the sealed pool at the outlet by the grate conveyor, and then loaded into the product collector. The copper wire can be used as raw material for producing refined copper.
The gas generated by pyrolysis is sent to the afterburning chamber to burn combustible substances, and then sent to the top of the reactor to absorb chlorine gas with calcium oxide and then discharged. The generated calcium chloride can be used as building materials.
Extended data:
The significance of recycling copper scrap (including copper scrap wire);
Copper and copper-based materials, whether exposed or wrapped in the final product, can be recycled at all stages of the product life cycle. Generally speaking, more than half of the waste copper used for regeneration is new waste copper. About 1/3 of all waste copper is returned to the market in the form of refined copper after reprocessing, and the other 2/3 is reused in the form of impure copper or copper alloy.
The premise of direct application of copper scrap is strict classification, stacking and sorting. The direct application of waste copper has the advantages of simplified process, simple equipment, high recovery rate, low energy consumption, low cost and light pollution. At present, waste cables and wires are a kind of old copper scrap with large quantity and high recycling rate.
In contrast, the amount of copper recovered from waste electrical appliances and automobiles is much lower, but at present, most of the research on copper scrap treatment focuses on the recovery of copper scrap from these resources.
There is no rigid standard in this respect in China, but the speed of industrialization in China is relatively fast, and the social and economic environment faced by the recycling, trade and recycling industries of waste non-ferrous metals has undergone major changes.
Not only has the variety composition of waste non-ferrous metals changed greatly, but also a large number of foreign waste non-ferrous metals and various available wastes have flooded into China, providing a rich source of raw materials for the production of non-ferrous metals in China, and also putting forward new requirements for the production and processing of recycled non-ferrous metals.
Therefore, China is also stepping up the formulation of scrap metal standards. The Classification and Technical Conditions of Copper and Copper Alloy Wastes, which was compiled by the Recycling Metals Branch of China Nonferrous Metals Industry Association, has been included in the national technical standard revision plan.
The new classification standard of copper scrap recycling will refer to the classification standard of waste nonferrous metals in the United States and the classification technical standard in Europe, and be revised according to the actual situation of China's recycled nonferrous metals industry, so as to make it more conducive to the implementation of enterprises and management departments.
Most of the copper scrap in China is imported, and now it mainly comes from the United States, Japan, Germany and Russia, among which the United States ranks first, and the United States has strict regulations on the management of copper scrap. This paper takes the classification standard of America as a typical introduction. Copper scrap in America is classified according to its purity.
The American Institute of Scrap Metal Recycling even subdivided copper and its alloys into 53 categories. In the United States, the copper material containing more than 99% Cu is usually called 1 copper, which can be directly remelted and used without further processing. Copper with a minimum copper content of 94.5% is called No.2 copper. This waste copper must be remelted before it can be used in the form of metallic copper.
Other common classification brands are lead brass, brass and low zinc brass, shell brass, automobile radiator, high copper brass (red brass), high-speed cutting brass and so on, which are widely used. Automobile waste is directly regenerated and used to reprocess brass products. It is in the form of alloy and has the same composition. For manufacturers, its main advantage is that it greatly reduces the cost of net metal consumption.