A collaborative disposal system for copper-containing sludge and waste circuit boards

Abstract

The present invention discloses a coordinated disposal system for copper-containing sludge and waste circuit boards, comprising a smelting section, a grate incineration section, and a spray gun provided on the smelting section. The upper portion of the smelting section is connected and communicated with the lower portion of the grate incineration section. After pretreatment, the waste circuit boards are sent into the grate incineration section for incineration, and the ash produced by the incineration is discharged downward into the molten pool in the smelting section for smelting. After pretreatment, the copper-containing sludge is blown into the molten pool in the smelting section through the spray gun for smelting. The flue gas and air in the smelting section enter the grate incineration section to supply heat and oxygen to the grate incineration section. Compared with the prior art, the present invention has the advantages of being compact and simpler in structure, and having improved heat and mass transfer.

Description

Technical Field

[0001] The present invention belongs to the field of resource recovery and treatment, and in particular relates to a coordinated disposal system for copper-containing sludge and waste circuit boards. Background Art

[0002] Industrial sludge, especially electroplating sludge and stainless steel pickling sludge, contains a variety of metal components and has complex properties, making it a recognized public nuisance both domestically and internationally. Recovering high concentrations of metals such as copper, nickel, chromium, and iron would not only alleviate environmental pollution and achieve cleaner production, but also offer significant ecological and economic benefits. Existing treatment processes include oxygen-enriched bath smelting and blast furnace smelting. Compared to blast furnace smelting, bath smelting offers advantages such as a high degree of automation, high processing capacity, low flue gas emissions, and greater adaptability to raw materials.

[0003] With the development of the electronics industry, the amount of waste circuit boards has gradually increased, bringing with it increasingly serious environmental pollution and human health problems. Currently, there are three recycling methods for waste circuit boards, namely pyrolysis, wet recycling, and physical recycling.

[0004] Hydrometallurgy involves dissolving the metals in scrap printed circuit boards (PCBs) or metal concentrates in a medium such as strong acid or alkali (sulfuric acid, nitric acid, or ammonia / ammonium salts). The metals are then recovered through extraction, electrolysis, leaching, and distillation. While hydrometallurgical processing offers advantages such as high recovery rates and the absence of toxic and hazardous gases (such as dioxins), its development is limited by its complex processes, long recovery times, and the need for rigorous wastewater treatment.

[0005] Pyrometallurgical treatment primarily uses incineration, sintering, pyrolysis, and smelting to decompose organic matter from waste circuit boards while simultaneously recovering valuable metals. Pyrometallurgical treatment offers advantages such as simple processes, large processing capacity, and high recycling efficiency. However, its disadvantages include relatively high technical investment and complex exhaust gas treatment. Summary of the Invention

[0006] In order to overcome the above-mentioned defects in the prior art, the purpose of the present invention is to provide a coordinated disposal system for copper-containing sludge and waste circuit boards.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a coordinated disposal system for copper-containing sludge and waste circuit boards, including a smelting part, a grate incineration part and a spray gun arranged on the smelting part.

[0008] The upper portion of the smelting portion is connected and communicated with the lower portion of the grate incineration portion.

[0009] After pre-treatment, the waste circuit boards are sent to the grate incineration section for incineration, and the ash generated by the incineration is discharged downward into the molten pool in the smelting section for smelting.

[0010] After pretreatment, the copper-containing sludge is blown into the molten pool in the smelting part through the spray gun for smelting.

[0011] The flue gas and air in the smelting section enter the grate incineration section to supply heat and oxygen to the grate incineration section.

[0012] During operation, the movement of the grate promotes the incineration of the circuit boards, and its reciprocating motion pushes the ash and slag from the pyrolysis and gasification of the waste circuit boards into the molten pool in the smelting section. The smelting section and grate incineration section are connected together, which has the advantage of a compact structure.

[0013] Furthermore, compared to existing molten pool smelting furnaces, one side of the grate incineration section is directly connected to the smelting section, improving heat and mass transfer. The hot flue gas from the smelting section is discharged directly into the grate incineration section, dehydrating and drying the circuit boards inside the grate incineration section while also heating them. The resulting ash, still at a high temperature, is pushed directly into the molten pool, reducing heat loss.

[0014] Optionally, the lance extends below the liquid level of the molten pool in the smelting section. In this arrangement, the blown-in material directly enters the molten pool and is not easily carried out or lifted upwards by the action of the flue gas.

[0015] Optionally, the spray gun is installed on the top of the smelting part to form a top-blowing structure, and the spray gun is inserted vertically downward into the molten pool to prevent the molten liquid from pouring into the spray gun.

[0016] Optionally, the spray gun comprises:

[0017] a first sleeve, the interior of which forms a fuel passage;

[0018] a second sleeve sleeved outside the first sleeve, wherein a first air passage is formed between the first and second sleeves;

[0019] A third sleeve is sleeved on the outside of the second sleeve, and a charge channel is formed between the second and third sleeves for passing the pretreated copper-containing sludge;

[0020] A fourth sleeve is sleeved on the outside of the third sleeve, and a second air channel is formed between the third and fourth sleeves.

[0021] The first air channel can be used to introduce oxygen-enriched air required for smelting, and the second air channel can be used to introduce part of the air required for circuit board incineration.

[0022] The air required for incineration, mixed with flue gas, enters the grate combustion chamber, where the temperature is high, exceeding 1000°C and reaching approximately 1300°C. This eliminates the need for a separate heating system for the air entering the grate, simplifying the overall system structure. Maintaining a high temperature within the grate combustion chamber also prevents the formation of dioxins. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the coordinated disposal system of copper-containing sludge and waste circuit boards in an embodiment.

[0024] Figure 2 Schematic cross-section of the spray gun in the embodiment.

[0025] Description of the figure number:

[0026] 1. Oxygen-enriched bath smelting furnace, 10. Smelting section, 11. Grate incineration section, 12. Liquid discharge port, 13. Slag discharge port.

[0027] 2. Spray gun, 20. First sleeve, 21. Fuel channel, 22. Second sleeve, 23. First air channel, 24. Third sleeve, 25. Charge channel, 26. Fourth sleeve, 27. Second air channel.

[0028] 3. Low-temperature dryer. 4. Pneumatic conveying device. 5. Crusher. 6. Combustion chamber. 7. Waste heat boiler. 8. Flue gas purification system. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0030] refer to Figure 1 As shown, the collaborative disposal system of this embodiment mainly includes an oxygen-enriched molten pool smelting furnace 1, which includes a smelting section 10 and a grate incineration section 11.

[0031] The upper part of the smelting part 10 is connected to the lower part of the grate incineration part 11, and the smelting part 10 is also provided with a spray gun 2. During operation, the following processes are mainly involved:

[0032] After pretreatment, the copper-containing sludge is fed into the smelting section 10 through the spray gun 2. After the smelting section 10 is started, the lower part thereof is a molten pool. Optionally, the spray gun 2 extends below the liquid level of the molten pool.

[0033] After pretreatment, the waste circuit boards are sent to the grate incineration section 11 for incineration, where the organic matter therein is pyrolyzed and gasified, and the generated ash is discharged downward into the smelting section 10 for smelting.

[0034] The lower portion of the smelting section 10 is provided with a liquid discharge port 12 for discharging the molten copper obtained by smelting. The lower portion of the smelting section 10 is also provided with a slag discharge port 13 for discharging slag.

[0035] In the grate incineration section 11, the waste circuit boards undergo pyrolysis and incineration gasification, and the reciprocating motion of the grate moderately and slowly stirs the waste circuit boards to promote combustion, while gradually pushing the ash toward the smelting section to fall into the molten pool of the smelting section 10, thereby improving heat and mass transfer in the disposal of the waste circuit boards.

[0036] In some embodiments, the smelting section 10 is a substantially straight cylindrical structure, and the lance 2 is installed on the top of the smelting section 10 to form a top-blowing structure.

[0037] Optionally, in some embodiments, the spray gun 2 is a multi-layer sleeve structure nested from the inside to the outside.

[0038] refer to Figure 2 As shown, the spray gun 2 includes:

[0039] A first sleeve 20 , the interior of which forms a fuel passage 21 ;

[0040] a second sleeve 22 sleeved outside the first sleeve 20, with a first air passage 23 formed between the first and second sleeves;

[0041] A third sleeve 24 is sleeved on the outside of the second sleeve 22, and a charge channel 25 is formed between the second and third sleeves for passing the pre-treated copper-containing sludge;

[0042] A fourth sleeve 26 is sleeved on the outside of the third sleeve 24 , and a second air passage 27 is formed between the third and fourth sleeves.

[0043] The fuel channel 21 is used to blow in the fuel required for the smelting reaction, and natural gas, coal powder, etc. can be selected. When solid fuel such as coal powder is used, a carrier gas is required.

[0044] The first air passage 23 is used to introduce air to provide oxygen to the fuel. Optionally, the air introduced through the first air passage 23 is oxygen-enriched air with an oxygen concentration of 40-80%.

[0045] The second air passage 27 is used to introduce air required for pyrolysis and gasification of the waste circuit boards. Optionally, the amount of air introduced through the second air passage 27 is 25-30% of the amount of air required for incineration of the waste circuit boards.

[0046] Furthermore, to extend the life of the spray gun 2, slag is formed on the surface of the spray gun 2 during use. During the slag forming process, the fuel channel 21 and the charge channel 25 do not spray any material. The spray gun 2 is placed 10 to 200 mm above the liquid surface of the molten pool and maintained there for at least 60 seconds. At least one of the first air channel 23 and the second air channel 27 blows air toward the liquid surface of the molten pool, causing some fine slag particles to splash onto the surface of the spray gun 2. Under the action of ventilation cooling in the first air channel 23 and the second air channel 27, a condensed slag layer is formed on the surface of the spray gun 2.

[0047] Optionally, the time for keeping the lance 2 above the liquid surface of the molten pool may be several times of 60 seconds.

[0048] The condensed slag layer can isolate the spray gun 2 from the melt when the spray gun 2 is inserted below the liquid level of the molten pool, thereby protecting the spray gun 2 and increasing its service life.

[0049] Optionally, during the smelting process, the lower outlet of the lance 2 is placed 200 to 300 mm below the liquid surface of the molten pool.

[0050] In some embodiments, the copper-containing sludge is sent to a low-temperature dryer 3 for drying. The low-temperature dryer 3 is connected to the spray gun 2 by a pneumatic conveying device 4, which pneumatically conveys the dried copper-containing sludge to the spray gun 2 and blows it into the molten pool.

[0051] The scrap circuit boards are pre-processed to remove the electronic components and obtain the bare boards.

[0052] In some embodiments, the bare boards of the pre-treated waste circuit boards are fed into a crusher 5 to obtain scraps. The scraps and smelting auxiliary materials are conveyed to the grate incineration section 11. The smelting auxiliary materials include but are not limited to reducing agents and slag forming agents.

[0053] The particle size of the scraps of waste circuit boards is 10 to 30 mm.

[0054] The scraps of waste circuit boards and smelting auxiliary materials are preferably fed into the grate incineration section 11 via a water-cooled screw conveyor.

[0055] The crushed materials just input into the grate incineration section 11 are located on the surface layer and are dehydrated and dried under the action of the high-temperature flue gas discharged from the smelting section 10. The temperature of the high-temperature flue gas is nearly 1300°C, which is higher than the temperature required for pyrolysis and gasification of the crushed materials. The dried crushed materials can be pyrolyzed and gasified to achieve incineration treatment.

[0056] The upper portion of the grate burning portion 11 is connected to the combustion chamber 6 through a flue to perform secondary combustion and remove combustible gases in the flue gas.

[0057] The combustion chamber 6 can be connected to a waste heat boiler 7 to recover waste heat and part of the smoke. Optionally, the waste heat boiler 7 can output steam that is fed into the low-temperature dryer 3 for sludge drying, thereby recovering waste heat.

[0058] The waste heat boiler 7 can be connected to a flue gas purification system 8, and the flue gas discharged from the waste heat boiler 7 is processed by the flue gas purification system 8 and then discharged in compliance with emission standards.

[0059] The flue gas purification system 8 is an existing technology, which can be processed in sequence including but not limited to a quenching tower, activated carbon injection, slaked lime injection, bag filter, two-stage wet desulfurization, and wet electrostatic demisting.

[0060] The embodiments of the present invention are only used to illustrate the present invention and do not limit the scope of the claims. Other substantially equivalent alternatives that can be thought of by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A system for the coordinated disposal of copper-containing sludge and waste circuit boards, characterized in that: include: Melting Department, a grate incineration section whose lower portion is connected and communicated with the upper portion of the smelting section, and A spray gun provided on the smelting section, wherein: After pre-treatment, the waste circuit boards are sent to the grate incineration section for incineration, and the ash produced by the incineration is discharged downward into the molten pool in the smelting section for smelting; After pretreatment, the copper-containing sludge is blown into the molten pool in the smelting section through the spray gun for smelting; The flue gas and air in the smelting section enter the grate incineration section to provide heat and oxygen to the grate incineration section; The spray gun comprises: a first sleeve, the interior of which forms a fuel passage; a second sleeve sleeved outside the first sleeve, wherein a first air passage is formed between the first and second sleeves; A third sleeve is sleeved on the outside of the second sleeve, and a charge channel is formed between the second and third sleeves for passing the pretreated copper-containing sludge; a fourth sleeve sleeved outside the third sleeve, with a second air passage formed between the third and fourth sleeves; When the spray gun is used, slag may form on the surface. During the slag forming process: The fuel channel and the charge channel do not spray any material, and at least one of the first air channel and the second air channel sprays air toward the liquid surface of the molten pool, so that some fine slag particles splash onto the surface of the lance to form a condensed slag layer attached to the surface of the lance, wherein: The spray gun is placed 10 to 200 mm above the liquid surface of the molten pool and maintained for no less than 60 seconds.

2. The collaborative disposal system according to claim 1, characterized in that: The lance extends into the smelting section below the liquid level of the molten pool.

3. The collaborative disposal system according to claim 1, characterized in that: A liquid discharge port and a slag discharge port are provided at the lower portion of the smelting part.

4. The collaborative disposal system according to claim 1, characterized in that: The lance is installed on the top of the smelting part to form a top blowing structure.

5. The collaborative disposal system according to claim 1, characterized in that: The air introduced through the first air channel is oxygen-enriched air with an oxygen concentration of 40 to 80%; The amount of air introduced through the second air passage is 25-30% of the amount of air required for incineration of waste circuit boards.

6. The co-processing system according to claim 1, characterized in that: The lower outlet of the spray gun is placed 200 to 300 mm below the liquid surface of the molten pool.

7. The co-processing system according to claim 1, characterized in that: The spray gun is used to connect to a pneumatic conveying device, and the pneumatic conveying device is used to connect to a low-temperature drying machine.

8. The co-processing system according to claim 7, characterized in that: The grate incineration part is connected to the combustion chamber through a flue, the combustion chamber is connected to the waste heat boiler, and the waste heat boiler is connected to the flue gas purification system, wherein the waste heat boiler can output steam and pass it into the low-temperature drying machine.

9. The co-processing system according to claim 1, characterized in that: The pre-treated bare board scraps of the waste circuit boards and the smelting auxiliary materials are fed into the grate incineration part through a water-cooled screw conveyor.

10. The co-processing system according to claim 9, characterized in that: The particle size of the scraps of waste circuit boards is 10 to 30 mm.

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