Pretreatment of waste non-ferrous metals - disintegration of waste and scrap

Disintegration of scrap and scrap

The purpose of the disintegration process is to remove black metal inlays and non-metallic inlays, to decompose the various metal and alloy components that are mechanically joined, and to reduce the size of the scrap to a size that facilitates subsequent processing and transportation. weight.

Disassembly and disassembly is carried out only in the case where it is necessary to recover valuable parts and products (ball bearings, fasteners) from the waste. When disassembling and disassembling, a tongs tool, an electric nut wrench, a wind chisel and other auxiliary equipment are generally used. This disintegration usually uses a method of destruction - cutting, breaking, and breaking.

The disintegration process includes: cutting, crushing and grinding, packing and briquetting, waste cable, waste battery, waste motor and other types of recycled raw materials.

Cutting and disassembling large pieces of scrap to a specified outer shape, generally using flame cutting and mechanical shearing. Flame cutting is based on the principle that a metal ignites in an oxygen stream. In the case of flame cutting, the metal is heated to a strong oxidation temperature, and then the metal is melted in a stream of oxygen which can be blown off by the slit to produce oxides and molten metal particles. Flame cutting is suitable for scrap metal with poor thermal conductivity. At the same time, the strong oxidation temperature of metal (alloy) should be lower than its melting temperature.

The temperature required for the process is maintained by the exothermic reaction of the oxygen oxidizing metal and the exothermic fuel combustion. The heat released by the metal is 2 to 4 times higher than the heat supplied by the preheated flame. However, fuel combustion during flame cutting is necessary because the cold metal must be heated to the point where it can be oxidized with industrial oxygen. The lower the thermal conductivity of the metal, the higher the rate of flame cutting. Fuel combustion ensures concentrated heating of the cutting point metal and high velocity production of the liquid phase.

Commonly used for flame cutting oxygen and a liquid fuel (kerosene) or gas fuel (acetylene, propane - butane, natural gas or coke gas) burner for the cutter. This method is most suitable for cutting scrap parts.

The main disadvantage of flame cutting is that oxidation causes a large amount of metal loss. In addition, high thermal conductivity metals such as copper , aluminum and copper-aluminum alloys cannot be flame cut.

The large-scale waste parts are decomposed by arc cutting, and their cutting ability is 2 to 3 times higher than that of flame cutting. For arc cutting, a carbon electrode, a graphite electrode, and a metal electrode are generally used, and a direct current (rarely alternating current) device can also be used. The metal loss caused by oxidation during arc cutting is also large.

Another method of arc cutting is air-arc cutting, which has not been adopted by Soviet remanufactured non-ferrous metallurgical companies until recently. The essence of air-arc cutting is to melt the metal with an electric arc and then blow the metal away from the cut with a stream of compressed air.

In the case of air-arc cutting of copper and its alloys (Fig. 1), a positive polarity direct current is used to generate an arc, and the part is connected to the positive electrode of the power source, and if it is a carbon (graphite) electrode, it is connected to the negative electrode terminal. This ensures maximum stability of the cut and reduces the unit consumption of electrodes, electricity and air. The resulting arc melts the metal and a stream of compressed air in parallel with the electrode blows the metal away. Current and air enter the cut through the combined current-air delivery line through the pipe and terminal block. Air consumption can be adjusted with the knob. The electrodes are pressed with a lever with a ceramic splint and a spring leaf. The conductive part is protected by an insulating plate and a handle. Thus, the air-arc cutter becomes a high current electrode clip combined with the air supply unit.

The following is the technical data of the PBД-81 cutter:

Current intensity (A) 1500

Air pressure (MPa) 0.2~0.6

Air tillage at 0.4 MPa ( ^m3 / hour) 60

Carbon (graphite) electrode size (mm)
Square section 10×10, 16×16
Rectangular section 10×20, 10×30

Length (mm) 350

Figure 1 Schematic diagram of air-arc cutting

1-cut parts; 2-arc; 3-electrode; 4-air flow; 5-terminal board;

6-lever; 7-insulation board; 8-pipe; 9-handle; 10-knob; 11-current-air duct

The power supply adopts a BДу-1201 type welded rectifier with a tilted appearance. When using the BДM-1001, BДM-1101, and BДM-1601 multi-position welding rectifiers to adjust each current, add 6 to 9 ΡБ-300 balance varistor. The varistor is connected in series with the main mode, but the varistor is connected in parallel. The power supply rated current used for such cutting shall be not less than 500 amps and the operating voltage shall be 40 to 60 volts.

Large-scale scrap copper (waste refrigerators, waste heat exchangers, waste busbars, waste containers, waste ship propellers, etc.) developed by the Ural CM Kirov Institute of Technology and promoted in Kirovgrad Copper Co., Ltd. The method of disintegration, compared with flame cutting, can increase labor productivity by 5 times and can cut waste parts up to 300 mm thick. [next]

Plasma-arc cutting methods are becoming more and more widely used in various enterprises. The essence of this method is to supply a certain flow of gas (nitrogen, argon, air, hydrogen). At this time, the arc shrinks and its body is converted into a highly ionized state to generate plasma. The plasma temperature can reach 20,000 to 30,000 ° C, and the jet velocity is 2000 to 3000 m / sec. Also, if an arc is made between electrodes separate from the metal being cut, a plasma arc is generated, and if it is made between the electrode and the metal, a plasma stream is generated.

The main portion of the plasma-arc cutting device (Fig. 2) is a water-cooled plasma flow generator, and the plasma-generating gas is an argon-hydrogen mixed gas and air.

Fig. 2 Schematic diagram of plasma solitary (a), plasma flow (δ) cutting and cutting device (ь)

1-cut metal; 2-power supply; 3-oscillator; 4-variable resistor for adjusting auxiliary arc;

5-plasma flow generator; 6-plasma flow; 7-plasma arc; 8-gas cylinder; 9-balance varistor

The negatively charged electrode (cathode) is made of tungsten, which is strongly oxidized at high temperatures. To prevent oxidation, an argon or argon-hydrogen mixed gas may be used. However, these gases are expensive and scarce, and hydrogen is also in danger of explosion.

In recent years, nitrogen or air has been widely used as a gas for generating plasma. When air is used, the cylinder is no longer used because the air required for cutting is compressed air (6 × 10 ⁵ Pa) supplied directly from the factory air main. However, since the air can oxidize not only the metal to be cut but also the tungsten electrode, the tungsten electrode cannot be used.

EO Paton Welding Research Institute, Academy of Sciences of Ukraine proof, some metals such as zirconium, hafnium, beryllium, thorium can be generated at the ion temperature stable refractory oxide. This oxide prevents further oxidation of the cathode. According to this research, a device with a zirconium cathode was fabricated, which uses atmospheric action as a plasma generating gas.

The Ural CM Kirov Institute of Technology successfully used the AПP-401 device for air-plasma cutting industrial trials of scrap copper. The cutting system is shown in Table 2.

Table 1 Best working system for air-plasma cutting copper and copper alloy

Thick metal (mm)	current intensity (an)	Nozzle hole diameter (mm)	air pressure (megapascal)	Air consumption (m 3 / hour)	Cutting speed (m/min)
10	150	2.0	80	1.0	1.0
20	200	2.5	90	2.5	0.7
30	250	2.5	100	3.0	0.5
40	300	3.0	110	3.5	0.4
50	400	3.0	120	4.0	0.3

Note: The voltage is 120 to 160 volts.

Plasma-arc cutting has the advantages of high efficiency, high productivity, and low metal burning loss, and is suitable for the disintegration of copper-based and nickel -based recycled raw materials and waste high-alloy steel.

Excavation of oversized spare parts, waste armored cables, and waste wire reels, dismantling waste radiators and other various scrap metal, generally using crocodile shears and hydraulic press shears (sickle type) ). Cut small pieces of scrap with a crocodile shear (Figure 3). All kinds of shearing machines are equipped with casting stands, fixed scissors on the base, and movable cast steel slabs with scissors can swing on the shaft. There are various types of crocodile shears used by companies that have all-recycled non-ferrous metal complexes (Table 3).

Figure 3 16H-315 crocodile shear
1-frame; 2-fixed scissors; 3-active scissors; 4-compressor;
5-upper plate; 6-rab; 7-upper plate shaft; 8-coupling; 9-pulley; 10-two-stage reducer [next]

Table 3 Technical parameters of crocodile shears

index	H-313 type	Type HA-313	H-315 type	H-316 type	H-2228 type	H-2230 type	H-2311 type
Knife length (mm)	300	500	600	1000	630	300	1000
Scissors per minute	40	40	twenty two	16	40	30	20
Permissible section of the metal being cut (mm):
square	50×50	50×50	90×90	120×120	56×56	90×90	120×120
Round	60	60	100	130	63	100	130
Belt, plate	20	25	twenty two	30	20	36	40
Groove (number)	18	18	36	40	twenty four	40	40
Tube shape (diameter)	140	140	250	250	250	300	400
Motor power (kW)	14	14	14	38	13	twenty one	42

Cutting waste non-ferrous metals with a large cross section, suitable for various hydraulic shears. Figure 4 is one of many hydraulic shears. It consists of a shearing machine with scissors and squeezing device, a feeding device with silo, bin and ejector, as well as hydraulic transmission components and control system. The shearing process is divided into several stages. The raw material was dropped into the charging tank from the receiving bin, and then the raw material was sent from the charging tank to the pre-pressing chamber by a hydraulic pusher with a stress of 5 MPa, and pre-compressed with a hydraulic compactor with a stress of 32 MPa. At the end of the pre-pressing, the upper scissors is lifted, and the pusher pushes the material to the predetermined shear size (700-1200 mm) position, after which the pressed scrap metal is cut into pieces by the fixed scissors. When the last piece of metal is pushed, the pusher returns to the starting position.

Figure 4 H-2338 Hydraulic Shearing Machine
1-bin; 2-loading tank; 3-hydraulic pusher; 4-pre-pressing chamber; 5-hydraulic compactor; 6-upper knife; 7-lower knife

The H-2338 hydraulic shearing machine is semi-automated and has a large loading tank (7000 x 1600 mm) and a long knife (1650 mm) with a maximum stroke of 950 mm. The stroke of the knife is 3 to 4 per minute. Times. Using this shear, the scrap metal of the following sections can be cut: circular and square sections - 120 to 125 mm; slotted section 40 and strip and plate section - 1400 x 56 mm. Its shear capacity is 8 to 15 tons / hour.

Many regenerative non-ferrous metallurgical companies are increasingly using the AKHA-type hydraulic shear combination machine, which is produced by the Soviet Union of sub-speed forging equipment production. After the scrap metal is sent to the loading chamber (4800 × 2500 × 800 mm), it is compacted by a pre-compression machine. The size of the loading chamber becomes smaller at the end of the preload (4800 x 750 x 500 mm). The hydraulic cylinders for preloading and filling chamber glands are rated at 1500 kN. The extruded scrap metal is fed by the feeding machine into the nozzle of the shearing machine and under the scissors. The compactor further compacts the scrap metal and holds it firmly within the width of the shearer during the shearing process. The AKHA type combiner cuts pre-compressed scrap metal while continuously loading new materials.

The combination machine can produce a shear force of 3150 kN, which can cut: round section waste with a diameter of less than 100 mm; square section waste with a length of 90 mm; waste board with a thickness of 50 mm and a width of 700 mm or less . The length of the scissors is not less than 800 mm, the number of shears at rated load is 5 times per minute, and the maximum stroke of the scissors is 650 mm.

Cutting the waste radiator of cars and tractors, it is suitable to use a special hydraulic shear (Figure 5). This special hydraulic shear can be manually and semi-automatically operated. The shearing machine with a shear force of 4000 kN has a movable knife stroke of 300 mm and can cut waste radiators with a cross-section of 970×250 mm.

Figure 5 Hydraulic shears for cutting waste radiators

1-fixed scissors; 2-tablet; 3-active scissors;

4-compressor; 5-piston rod; 6-hydraulic cylinder; 7-frame; 8-rail

Crushing and grinding Waste non-ferrous metals that require crushing and grinding include casting waste and scrap, lightweight waste parts of excess size, waste and waste wires, waste stator windings, waste motors, lead- acid batteries, waste, Packed waste non-ferrous metals, etc.

According to the size of the crushed product, the crusher is divided into a coarse crusher (250 to 300 mm), a medium crusher (25 to 30 mm) and a fine crusher (less than 3 mm). Various crushers can be either general purpose or dedicated. General purpose crushers include: drop hammer crushers , jaw crushers , hammer crushers and rotor crushers. Grinding generally uses a rotor mill and a crusher. The special crusher has a tearing machine, a canning machine, and a chip roughing roller. [next]

The drop hammer crusher is suitable for crushing large-scale waste castings , slag and scum, and is classified into two types: fixed type (K-21 type, K-26 type) (Fig. 6) and mobile type (MC-32 type). Drop hammer crushing is a mechanical process that uses a falling steel body-falling hammer to break up waste. Drop weights range from 500 to 1000 kilograms to 6 to 15 tons. The maximum size of the raw material block is 1500-2000 mm, and the maximum size of the broken material block is 500-300 mm. The drop hammer crusher has a capacity to process heavy non-ferrous scrap of 2.0 to 2.5 tons per hour.

Figure 6 K-26 small drop hammer crusher

1-broken position; 2-metal frame; 3-height limiter;

4-pulley; 5-hanger; 6-drop hammer

The crocodile crusher is suitable for medium and fine crushing of slag, flux and waste battery. The crocodile crusher has a reduction ratio of 3 to 5, which is highly reliable and easy to use.

For the crushing of waste cables, waste wires, waste automobile batteries, slag, etc., it is suitable to use impact type (hammer and rotor type) crushers.

In a hammer crusher, it is broken by a hammer hinged on a rotating rotor. The magnitude of the crushing impact depends on the weight of the hammer and the rotational speed of the rotor.

In the rotor crusher, the object to be crushed is a crucible that is firmly fixed to the rotating rotor. The structure of the hammer (杵槌) type crusher is as shown in (Fig. 7). The M8-бБ crusher weighs 2310 kg and has 6 rows of 96 hammers on a 800 mm diameter rotor. The rotor speed was 1000 rpm and the loading block was 200 mm. Hammer and rotor crushers have high productivity and high reduction rates (up to 50). The crushing capacity and crushing quality depend on the type of discharge screen, the size of the mesh, the distance between the hammer and the screen. This distance can be adjusted according to the type of material being crushed. When crushing waste cables, the spacing is generally 15 to 20 mm; when breaking the waste wires, the spacing is 2 to 3 mm; when crushing the waste castings, the spacing is generally 15 to 20 mm; when breaking the waste wires, the spacing is 2 to 3 mm; When crushing waste castings, the spacing is 35 to 45 mm.

Figure 7 M8- бБ type (a ) and M6-4 Б type (δ) hammer crusher

1-chassis; 2-rotor; 3-active sag; 4-loading port; 5--feeding screen; 6-shield

Some regenerative non-ferrous metallurgical enterprises in the Soviet Union used waste mills (formerly) West German Lindeman and Hami Mill of the United States to process waste non-ferrous metals. The Hamilton Mill's crusher (Fig. 8) has a preloading device that increases the crushing capacity. The rotor of the crusher is equipped with several movable cast steel hammers, and the broken materials are discharged through the sieve. The inner lining of the crusher casing is a protective panel made of wear-resistant steel and bolted. When the cover is opened, the material can enter the crusher. Using this crusher, it is possible to process waste boards with a maximum size of 3000 x 1400 mm and a thickness of 10 mm and block waste of 1100 x 600 x 600 mm. The broken material has a mass of 0 to 150 mm. The crushing capacity of the crusher is 10-20 tons/hour. [next]

Figure 8 Hami Mill's crusher

1-Preloading device; 2-rotor; 3-active hammer; 4-cutting rod; 5-grid screen; 6-cover

Lindemann's crusher (Fig. 9) can break waste and scrap (compressed scrap car casing) with a length of 5000 mm and a width of 1400 mm. The charging is carried out by a supply roller or a belt conveyor. The Lindemann KR-175/160 crusher has a rotor with a diameter of 1750 mm and a length of 1600 mm. There are 26 hammers on the rotor, each weighing 26 kg. The rotor speed is 600 rpm. The complete plant includes a wind sorter and magnetic separation and vacuum system.

Figure 9 Schneidermann crusher schematic

1- Loading system with supply roller and belt conveyor; 2-special type casing;

3- tear and pre-crush anvil; 4-reflection and rebound back;

5- scrap block; 6-screen 7-upper screen shut-off valve; 8-large particle discharge valve;

9- enter the fine particle outlet of the vacuum system; 10-hammer; 11-transport device; 12-vibration conveyor

When crushing aluminum-containing scrap, the productivity of the equipment can reach 20 tons / hour, and the size of the broken block is 0 - 85 mm. The dust discharged from the dust suction device does not exceed 20 mg/ ^m3 .

The Belarusian Renewable Non-Ferrous Metals Authority plans to use a pipeline containing Lindemann crushers for the treatment of lead-coated or aluminum-clad and woven sheathed copper cables. The processing capacity of the assembly line is 2.5 tons / hour.

The fine crushing of the recycled raw materials uses a hammer crusher, a knife crusher, and an attritor, a mill, and a pulverizer. The ИПР type pulverizer is suitable for the fine crushing of waste electric wires before the air separation of the wind selection workers. The ИПР-450 rotor mill consists of a shear chamber, a charging port, a blanking screen, a transmission and a ventilation system. A fixed knife is mounted on the body. The rotor with the movable knife rotates in the shear chamber. The cutting distance between the knife and the rotor is adjustable from 0.3 to 0.4 mm. There is a detachable sieve in the lower part of the fuselage, and the pulverized material is discharged through the sieve. The block size of the raw material is 300 mm. The production capacity of the pulverizer is 1500-2000 kg/hr for the waste battery and 400-500 kg/hr for the waste electric wire.

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