What Is Scrap Copper?

Common questions about building copper products: Copper and the commonly used copper family have been used for hundreds of years. They are one of the oldest metal families. During this period, many questions were raised about this metal, and a lot of research work was also done on it.

Copper scrap

Common questions about building copper products: Copper and the commonly used copper family have been used for hundreds of years. They are one of the oldest metal families. During this period, many questions were raised about this metal, and a lot of research work was also done on it.

Chinese name

Copper scrap

Attributes

One of the oldest metal families

The role of copper

Watertight seams

Chemical applications

Avoid scouring copper surfaces to expose precious metals

China does not have standards for copper scrap, but with the acceleration of China's industrialization, the socio-economic environment facing the recovery, trade and recycling of waste nonferrous metals has undergone major changes. Not only the composition of the types of waste nonferrous metals The changes are large, and a large amount of foreign waste and non-ferrous metals and various types of available waste materials have flowed into the country, providing a rich source of raw materials for the production of non-ferrous metals in China.

Virtually all scrap copper can be recycled. The regeneration process is simple. First sort the collected copper scraps. There is no contaminated copper scrap or the same composition.

The variety of scrap copper is complex, and the recovery and use skills and processes are different, but it is usually divided into two parts: pre-treatment and recycling. The so-called pre-disposal is to classify the heavy waste copper, sort out other mechanically mixed waste, remove the oil on the surface of the waste copper, etc., and get a single variety and relatively pure waste copper at the end to provide excellent materials for smelting. Then the smelting process was simplified. There are many ways to recycle waste copper, which can be divided into two categories, namely the direct use and direct use of waste copper. Direct use is to directly smelt high-quality scrap copper into refined copper or copper alloys. Direct use is to exercise to remove the base metal from the waste copper, cast it into anode plates, and then electrolyze to obtain electrolytic copper.

This article introduces the main points of the treatment of waste copper wires and cables in the pre-disposal skills, and the use of recyclable parts will introduce some of the foreign recycled copper plants' processes and patents.

(I) Pre-treatment of waste wires and cables

The intention of pre-disposal of waste wires and cables is to separate the copper wire and the insulation layer. There are four main methods:

1. Mechanical separation method, which can be divided into two types.

(1) Roller peeling machine method. This method is suitable for the disposal of waste wires and cables of the same diameter. China already has such equipment. The Wolfehampton plant in the United Kingdom chose this kind of equipment to strip waste wires and cables, which works well.

Waste wires and cables are first cut into line segments not exceeding 300 mm in length, and then manually fed into a special drum shredder. In the drum shredder, the wires and cables are broken and peeled, and the debris is from the bottom of the drum blade. The sieve with a diameter of 5 mm is leaking. The rotating speed of the drum is 3000 rpm. The diameter of the drum is 30 inches. The gap between the drum blade and the bottom sieve plate is 1.5 mm. Power of 30 kilowatts. The chips leaked from the sieve holes are sent to the silo with a belt, and then the chip feeder is sent to the shaker for selection. The copper chips, mixture and plastic fibers are obtained at the end. The copper chips can be used directly as copper The material can also be used to produce copper sulfate, and the mixture is returned to the reversing drum shredder for disposal. Plastic fibers can be sold as products. Each ton of waste wire and cable can produce 450-550 kg of copper shavings and 450-550 kg of plastic. It can dispose of 60 tons of materials a week, producing 30 tons of copper scraps and 30 tons of plastics. Replace the blade every 30 tons of waste cables and wires. The blade is made of high-speed east-west steel.

This process has the following characteristics:

A. The copper and plastic in the waste wires and cables can be summarized and recovered, and the level of induction is higher;

B. The copper scrap produced does not contain plastic at all, which reduces the pollution of the plastic to the atmosphere during melting;

C. The process is simple and easy to mechanize and automate;

The disadvantages of this type of equipment are high power consumption during the process and faster blade wear.

(2) Cutting-type peeling machine processing method. This method is suitable for handling large cables and wires, and a certain plant in Xiangfan, China has been able to produce such equipment.

2. Cryogenic freezing method

U.S. Patent No. 3,991,641 proposes the use of a low-temperature freezing method to separate the copper of the waste wires from the insulation.

The cryogenic freezing method is suitable for handling wires and cables of various specifications. The waste wire and cable are frozen to make the insulation layer brittle, and then broken by vibration to separate the insulation layer from the copper wire.

3. Chemical stripping method

In this method, an organic solvent is used to dissolve the insulation layer of the waste wire and reach the intention of separating the copper wire from the insulation layer. The advantage of this method is that high-quality copper wires can be obtained, but the disadvantage is that the solution is more difficult to handle and the solvent is more expensive. The development direction of this skill is to discuss a useful solvent that is useful for selling.

4. Thermal decomposition method

U.S. Patent No. 4,040,865 proposes to use a thermal decomposition method to burn off the insulation layer and obtain a copper wire.

The waste wires and cables are cut first, and then transported to the feeder to participate in the pyrolysis chamber pyrolysis. The pyrolyzed copper wires are sent by the grate conveyor to the water outlet of the discharge port, and then loaded into the product collector. Copper wire can be used as the material for producing refined copper. The gas generated by pyrolysis is sent to the afterburning chamber to burn off the combustible materials in it, and then sent to the top of the reactor to absorb the chlorine gas during the discharge with calcium oxide. The generated calcium chloride can be used as a building material.

(2) References on the recycling process of waste copper

The Kaiser Exercise Plant in Germany is a typical recycled copper plant and a representative old enterprise. The plant is located in Tmund. It was established in 1861 and has 700 employees. The plant covers an area of about 30 square kilometers and has an annual output of 115,000 tons of electrolytic copper. It also produces copper wire ingots, copper sulfate, nickel sulfate, zinc oxide, Lead-tin alloy and other products.

1. Process clarification

The Kaiser plant uses a two-stage method and a three-stage method. The selection of this process is conducive to reducing energy consumption and improving the inductive recovery rate of valuable metals. The production equipment is traditional blast furnace, converter, stationary reverberatory furnace and conventional electrolytic equipment. The plant has two blast furnaces, with a cross-sectional area of 3.75 square meters (2.5 × 1.5 meters) in the tuyere area, a daily disposal capacity of 150 tons, and a bed energy rate of 40 tons / square meter. Day and night, the coke rate is 17%, and the blast furnace waste slag contains copper <1% . In the meantime, one blast furnace is used to dispose of copper crumbs and powdery copper-containing materials, and the materials must be turned into pellets before entering the furnace; the other blast furnace is used to dispose of yellow copper and block copper-containing slag. The blast furnace produces 75-85% of black copper in two 30-ton converters. The two anode furnaces are fixed-type reflector furnaces with a bed area of 60 square meters. The unit fuel consumption is 70-80 kg / ton anode, and the furnace is lined with chrome-magnesia bricks. During the melting process of the reverberatory furnace, oxygen oxidation and wood insertion recovery method are used.

The electrolytic starting plate is produced with titanium mother board. The electrolytic cell is covered with a plastic cover to reduce heat loss. The steam consumption is 0.8 tons / ton of copper, the current density is 200 amps / meter2, the current efficiency is 95-97%, and the power consumption is 250 degrees / ton of copper. The ingot furnace is two 85-ton fixed reverberatory furnaces, lined with chrome-magnesium bricks, oxidized with oxygen, and restored by inserting wood. The oil consumption is 80 kg / ton of copper, and the product contains oxygen <250 ppm and sulfur 20 ppm. In addition to electrolytic copper, the material is also blended with about 7% of high-grade purple copper.

2. Process characteristics

The classification of waste copper in the plant is very complete. It is separated and piled up according to grade, variety and material shape. The recovery rate of copper is high, and the lead, tin, and zinc in the quality guess can be summarized and recovered. In addition, the starting electrode production line of the copper electrolysis workshop is depicted as a stepped starting electrode sheet holder, which has unique features.

(III) Recycled copper processed copper

The grade (above 92%) of purple copper is equivalent to the fire method of the anode furnace, and then directly mixed with other copper melts and cast into rod or slab. The plant has 2,700 employees and an annual output value of 650 million marks. The main products are various types of copper tubes, copper strips, copper plates, copper alloy bars, and profiles. The monthly output of various types of copper is about 12,000 tons.

1. Process clarification. There is a shaft furnace (ASDRCO-SHAFT-RURNACE) in Good Hope Metal Products Factory. The smelting capacity of the shaft furnace can be 20 tons / hour, 1000 standard meters 3 / hour. Natural gas, and SiC lining is selected.

Shaft furnace treats differently the molten copper from different copper materials. When smelting more than 99% purple copper and cathode copper, the copper liquid enters the continuous casting machine after passing through the holding furnace, or the copper liquid is directly sent to the semi-continuous casting machine to produce various types of rod or slab. When the shaft furnace smelts 92% -99% copper scrap, the copper liquid is sent to the converter or open hearth for the essence of fire method, and then the rod or slab is produced by the continuous casting machine or semi-continuous casting machine.

2.Process characteristics.

(1) In order to ensure the quality of the products, the classification and management of scrap copper are very strict.

(2) About purple copper with copper grades between 92-99%, melted in the shaft furnace and enter the essence of the converter or open hearth furnace. The refined copper liquid is directly cast into various slabs and rods, avoiding repeated smelting, which can improve the recovery rate of copper by more than 0.2%, save fuel equivalent to 400 kg / ton of copper, and have good economic benefits.

(3) The plant has the only large-diameter copper pipe casting production system in the world, with a diameter of 300-1500 mm and a maximum length of 11,000 mm.

(IV) Recover copper from mixed waste guessing

U.S. Patent No. 3,905,556 proposes a method for disposing of high-copper mixed waste materials with large copper content fluctuations. In the process, after the high content of mixed waste is crushed-wind separation-magnetic separation-shredding treatment, three layers of coarse, medium and fine materials are screened with three layers, and the three materials are based on the amount of metal contained, If the shape and variety are different, different reselection processes are used for disposal.

(5) Recover copper from waste arsenic

U.S. Patent No. 4,149,880 proposes a method for recovering copper from arsenic-containing waste. In this method, ash containing high arsenic is slurried and then leached in an autoclave. The leachate is removed by molybdenum and replaced with iron filings. The produced sponge copper is returned to the smelting system to produce metallic copper. Then the water treatment workshop will recover the arsenic.