Method and apparatus for recycling electronic waste

Abstract

The application provides an electronic waste recycling method and device, which comprises the following steps: adding a preset weight of crude metal blocks into a rotary furnace; heating the rotary furnace to melt the crude metal blocks into crude metal melt; continuously adding electronic waste with controllable mass and composition into the rotary furnace and inputting oxygen-enriched air or pure oxygen with controllable oxygen proportion; when the molten slag in the rotary furnace reaches a preset slag line height, stopping feeding and discharging the molten slag after standing; after multiple cycles of feeding, smelting, standing and slagging, when the metal volume in the rotary furnace meets the standard, pouring the molten metal into metal ingots; and the flue gas generated by the rotary furnace is purified through a flue gas purification system. The application can achieve the purpose of realizing self-heating reaction in the furnace. Under the stirring and mixing action of the molten body in the furnace, the inorganic substances in the electronic waste are enriched in the slag, and the metal is enriched in the crude metal melt, so that the metal recovery rate is greatly improved, and the flue gas generated by the rotary furnace meets the standard after being treated by the flue gas purification system.

Description

Technical Field

[0001] This invention relates to the field of electronic waste resource utilization technology, and more specifically, to a method and apparatus for electronic waste recycling and processing. Background Technology

[0002] With the rapid development of the electronics industry, the amount of electronic waste (waste circuit boards, electronic components, etc.) has increased dramatically. Electronic waste is rich in various valuable metals such as gold, silver, copper, iron, and aluminum, but its composition is complex (containing organic matter, halogen elements, heavy metals, etc.), and traditional recycling processes suffer from low metal recovery rates. Summary of the Invention

[0003] (a) Technical problems to be solved The technical problems to be solved by this invention are: low metal recovery rate in traditional pyrometallurgical electronic waste recycling processes; insufficient conversion of the calorific value of organic matter brought in by electronic waste into heat in the furnace to maintain the self-heating reaction in the furnace; high smelting production costs; large flue gas treatment volume; difficulty in controlling pollutants such as dioxins, acid gases and heavy metals in the flue gas, which can easily cause secondary pollution; and highly corrosive flue gas that can easily cause equipment corrosion, poor operational stability, large investment in flue gas treatment facilities, and high treatment costs.

[0004] (II) Technical Solution To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for recycling and processing electronic waste, comprising the following steps: S1. Add a pre-set weight of coarse metal blocks into the rotary kiln; S2. The rotary kiln is heated to melt the crude metal block into a crude metal melt. S3. Continuously add electronic waste and slag-forming agent (smelting auxiliary material) with controllable quality and composition into the rotary kiln, and introduce oxygen-enriched air or pure oxygen with controllable oxygen ratio; specifically, by controlling the amount of electronic waste continuously added and the oxygen concentration of the oxygen-enriched air introduced, the self-heating reaction and thermal balance in the furnace are maintained, and the furnace temperature is kept within the preset temperature range so that the smelting reaction of electronic waste can continue to proceed automatically and self-heating. S4. When the molten slag in the rotary kiln reaches the preset slag line height, stop feeding and let it stand. Then discharge the molten slag. After multiple cycles of feeding, smelting, standing, and slag discharge, when the metal volume in the rotary kiln reaches the standard, cast the molten metal into metal ingots. S5. The flue gas generated by the rotary kiln is purified by the flue gas purification system.

[0005] Preferably, the flue gas generated by the rotary kiln is purified by a flue gas purification system, including the following steps: The flue gas passes sequentially through a secondary combustion chamber, a denitrification reactor, a quench tower, a deacidification tower, a dust collector, a scrubbing tower, an activated carbon adsorption box, and a chimney. In the secondary combustion chamber, the flue gas undergoes secondary combustion to decompose unburned organic matter. In the quench tower, the flue gas is rapidly cooled. In the deacidification tower, the flue gas undergoes primary deacidification. In the dust collector, the flue gas undergoes secondary deacidification. In the scrubbing tower, the flue gas undergoes secondary deacidification. Finally, residual pollutants are adsorbed in the activated carbon adsorption box, and the flue gas is discharged through the chimney.

[0006] Preferably, the flue gas enters the secondary combustion chamber, where the unburned materials continue to burn. The temperature of the secondary combustion is controlled at 850-1200℃, the oxygen content is 4-12%, and the flue gas residence time is not less than 3 seconds.

[0007] Preferably, when the flue gas is rapidly cooled in the quench tower, the flue gas temperature drops from 850-1200℃ to 140-180℃ through the quench tower; Preferably, the crude metal is one or more of copper, iron, aluminum, zinc, lead, and tin, and the crude metal melt formed by its melting serves as a heat carrier and metal collector. Specifically, copper melt has a high recovery rate for gold and silver, while iron melt can solidify harmful metals such as lead and zinc, preventing them from entering the flue gas. Different crude metals can be selected according to different application scenarios.

[0008] Preferably, in step S2, the rotary kiln is heated to a first temperature T1 = T0 + (0, 200] °C, where T0 is the melting point of the valuable metal in the electronic waste; the rotary kiln in this application is different from the rotary kiln in the prior art. Rotary kilns mainly process domestic waste, etc., and their processing capacity for thermosetting plastics is limited.

[0009] And / or in step S3, the furnace temperature is controlled to a second temperature T2=T1+[0, 300]℃, where T0 is the melting point of the valuable metal in the electronic waste.

[0010] Secondly, the present invention also provides an electronic waste recycling and processing apparatus for implementing the aforementioned electronic waste recycling and processing method. The electronic waste recycling and processing apparatus includes a rotary kiln, a feeding device, a metering feeding component, a multi-channel burner, a fume hood, and a flue. The rotary kiln is used to smelt crude metal blocks and electronic waste. The feeding device is used to add a preset weight of crude metal blocks into the rotary kiln. The metering feeding component is used to add a preset weight of electronic waste and smelting auxiliary materials (such as slagging agents) into the rotary kiln. The multi-channel burner is used to introduce one or more of fuel, air, oxygen, or oxygen-enriched air into the rotary kiln. The inlet of the fume hood faces the furnace opening of the rotary kiln. The flue connects the fume hood to a flue gas purification system.

[0011] Preferably, the rotary kiln is a top-blown rotary kiln, which can be tilted to adjust the furnace opening to a vertical feeding position, an inclined smelting position, or a slag discharge / casting position with the furnace opening lower than the furnace bottom. The vertical feeding position is equipped with the feeding device, and the inclined smelting position is equipped with the metering feeding assembly, the multi-channel combustion gun, the fume hood, and the flue.

[0012] Preferably, it also includes a slag ladle and a metal casting ingot mold, with the slag ladle and the metal casting ingot mold provided at the inclined smelting position. The slag ladle is used to collect slag waste, and the metal casting ingot mold is used to collect molten metal.

[0013] Preferably, the flue gas purification system includes a secondary combustion chamber, a quench tower, a deacidification tower, a dust collector, a scrubbing tower, an activated carbon adsorption box, and a chimney, which are connected in sequence by pipelines.

[0014] (III) Beneficial Effects The above-described technical solution of the present invention has at least the following advantages: 1. In this invention, electronic waste of controllable quality and composition is continuously added to the rotary kiln, and oxygen-enriched air or pure oxygen with a controllable oxygen ratio is introduced. This ensures that the organic matter generated by the thermal decomposition of electronic waste in the kiln is partially combusted with oxygen and that a controllable thermal balance is maintained within the kiln, thereby achieving the purpose of self-heating reaction within the kiln. Simultaneously, after the electronic waste undergoes thermal pyrolysis in the kiln, the remaining substances, except for the flue gas, melt into the slag. As the kiln rotates, the slag and crude metal in the kiln come into full contact under the action of mechanical stirring and mixing. The crude metal melt acts as a metal collector, capturing the metal droplets contained in the slag after the thermal pyrolysis of the electronic waste, significantly improving the metal recovery rate. In step S2, the rotary kiln is heated to a first temperature T1 to ensure that the crude metal melt has good fluidity and to store energy for the next step of the electronic waste decomposition reaction. In step S3, the rotary kiln is heated to a second temperature T2 to promote the decomposition of electronic waste. The crude metal melt, as a heat carrier, provides sufficient heat for the pyrolysis of electronic waste, preventing insufficient heat during the start-up reaction, which would cause a large amount of black smoke to be generated in the furnace, making it impossible for the furnace to achieve a self-heating reaction and increasing the processing requirements of the secondary combustion chamber.

[0015] 2. In this invention, flue gas enters the secondary combustion chamber and continues to undergo a secondary combustion reaction with the air or oxygen-enriched air supplied to the secondary combustion chamber. In order to maintain the temperature of the secondary combustion at 850-1200℃ and the oxygen content at 4-12%, the oxygen concentration of the oxygen-enriched air supplied to the secondary combustion chamber can be adjusted to achieve a self-heating or semi-self-heating reaction in the secondary combustion chamber, thus saving operating costs.

[0016] 3. In this invention, the flue gas purification system specifically involves the flue gas sequentially passing through a secondary combustion chamber, a quench tower, a dust collector, a scrubbing tower, an activated carbon adsorption box, and a chimney for purification, thereby achieving the removal of dioxins and NOx. xDeep purification of acidic gases, heavy metals, and particulate matter ensures that emissions meet standards.

[0017] 4. In this invention, the metering and feeding components, rotary kiln, and flue gas purification system are highly integrated, the operation is continuous and highly automated, adaptable to industrial production, and saves labor costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the electronic waste recycling and processing device provided in Embodiment 1 of the present invention.

[0020] Figure 2 This is a schematic diagram of the electronic waste recycling and processing device provided in Embodiment 2 of the present invention.

[0021] Figure 3 This is a schematic diagram of the rotary kiln in the vertical feeding position provided in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the rotary kiln in the inclined smelting position provided in an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the rotary kiln in the slag discharge position provided in an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the rotary kiln in the casting position provided in an embodiment of the present invention.

[0025] The labels for the attached figures are as follows: 1. Rotary furnace; 2. Feeding device; 3. Metering feeding assembly; 4. Multi-channel combustion gun; 5. Fume hood; 6. Flue; 7. Flue gas purification system; 8. Slag ladle; 9. Metal casting ingot mold; 11. Furnace opening; 31. Metering hopper group; 32. Airlock feed hopper; 33. Feeding gun / pipe; 41. Air; 42. Oxygen; 43. Gas fuel; 71. Secondary combustion chamber; 72. Denitrification reactor; 73. Waste heat boiler; 74. Quenching tower; 75. Dry or semi-dry deacidification tower; 76. Bag or cartridge dust collector; 77. Scrubber; 78. Activated carbon adsorption box; 79. Chimney; 741. Fan. Detailed Implementation

[0026] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0028] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments: Example 1 like Figure 1 , Figures 3-6As shown, this embodiment of the invention provides an electronic waste recycling and processing device, including a rotary kiln 1, a feeding device 2, a metering feeding component 3, a multi-channel burner 4, a fume hood 5, and a flue 6. The rotary kiln 1 is used to smelt crude metal blocks and electronic waste. The feeding device 2 is used to add a preset weight of crude metal blocks into the rotary kiln 1. The metering feeding component 3 is used to continuously and quantitatively add a preset weight of electronic waste into the rotary kiln 1. The multi-channel burner 4 is used to introduce fuel and oxygen-enriched air or pure oxygen with a controllable oxygen ratio into the rotary kiln 1. The inlet of the fume hood 5 faces the furnace opening of the rotary kiln 1. The flue 6 connects the fume hood 5 to a flue gas purification system 7. The flue gas purification system 7 includes a secondary combustion chamber 71, a quench tower 74, a dry or semi-dry deacidification tower 75, a bag filter 76, a scrubbing tower 77, an activated carbon adsorption box 78, and a chimney 79, which are connected in sequence through pipes. The secondary combustion chamber 71 is connected to the outlet of the flue 6. Specifically, the metering and feeding assembly 3 includes a metering silo group 31, an airlock feed silo 32, and a feeding gun / pipe 33. One end of the airlock feed silo 32 is connected to the metering silo group 31, and the other end is connected to the feeding gun / pipe 33. The metering silo group 31 is used to weigh and meter electronic waste. The metered electronic waste is then transported to the rotary kiln 1 through the airlock feed silo 32 and the feeding gun / pipe 33. The metering silo group 31 includes at least one electronic waste silo and one auxiliary material silo, with a metering device in each silo to achieve continuous weighing and metering of materials. The airlock feed silo 32 receives the metered material and feeds it to the rotary kiln 1 at a uniform speed through the feeding gun / pipe 33, ensuring continuous and accurate feeding. The multi-channel combustion gun 4 can be supplied with fuel (such as natural gas), air, oxygen, or oxygen-enriched air. The gas ratio is adjusted by a control valve group to achieve precise control of the furnace temperature and atmosphere.

[0030] The rotary kiln 1 is a top-blown rotary kiln. The rotary kiln 1 can be rotated to be adjusted to a vertical feeding position, an inclined smelting position, or a slag discharge / casting position. The vertical feeding position is equipped with a feeding device 2, and the inclined smelting position is equipped with a metering feeding assembly 3, a multi-channel combustion gun 4, a fume hood 5, and a flue 6.

[0031] The electronic waste recycling and processing device also includes a slag ladle 8 and a metal casting ingot mold 9. The inclined smelting position is equipped with a slag ladle 8 and a metal casting ingot mold 9. The slag ladle 8 is used to receive slag waste, and the metal casting ingot mold 9 is used to receive molten metal.

[0032] Specifically, the flue gas sequentially passes through a secondary combustion chamber 71, a quench tower 74, a dry or semi-dry deacidification tower 75, a bag filter 76, a scrubbing tower 77, an activated carbon adsorption box 78, and a chimney 79. In the secondary combustion chamber 71, the flue gas undergoes secondary combustion to decompose organic matter; in the quench tower 74, it is quenched; in the dry or semi-dry deacidification tower 75, it is rapidly cooled; in the bag filter 76, it is deacidified; and in the scrubbing tower 77, it is desorbed, and residual pollutants are adsorbed in the activated carbon adsorption box 78. Finally, the flue gas is introduced into the chimney 79 for emission by an induced draft fan. In the dry or semi-dry deacidification tower, dry lime powder is sprayed to react with acidic gases to generate solid salts, which are collected by a bag filter or cartridge filter, achieving neutralization and deacidification while inhibiting dioxin resynthesis. The flue gas then enters an alkaline scrubbing deacidification tower for further deep deacidification; finally, the flue gas enters the activated carbon adsorption box to adsorb residual pollutants, completing deep purification.

[0033] This invention also provides a method for recycling and processing electronic waste, comprising the following steps: S1. Add a pre-set weight of coarse metal blocks into the rotary kiln 1. Specifically, first rotate the rotary kiln 1 to the vertical feeding position (furnace opening 11 facing upward), and add the metered coarse metal blocks (copper, iron, aluminum, etc.) through the feeding device 2.

[0034] S2. The rotary kiln 1 is heated to melt the crude metal block into a crude metal melt. Specifically, the rotary kiln 1 is rotated to the inclined smelting position (furnace opening 11 is directly opposite the inlet of the fume hood 5), a multi-channel combustion gun 4 is inserted and ignited, and the combustion gas and combustion-supporting gas (air / oxygen-enriched air) are heated. The flue gas enters the flue gas purification system 7 through the fume hood 5 and the flue duct 6. The furnace temperature is controlled to the first temperature T1 = T0 + (0, 200]℃ to melt the crude metal. The crude metal melt serves two purposes: 1. As a heat carrier, it provides heat for the pyrolysis of electronic waste and prevents the electronic waste from carbonizing due to insufficient pyrolysis temperature; 2. As a metal collector, it collects the molten metal droplets in the slag after the electronic waste has undergone thermal pyrolysis. The organic matter in the electronic waste decomposes to produce pyrolysis combustible gas, which serves as fuel and reducing gas to maintain the smelting process.

[0035] After the furnace temperature of rotary kiln 1 reaches the target, electronic waste and smelting auxiliary materials are metered by metering bin group 31 and fed by airlock feeding bin 32, and then uniformly fed into the furnace through feeding gun / pipe 33. Specifically, during the smelting process, the fuel valve is closed, and oxygen / air / oxygen-enriched air is injected through multi-channel combustion gun 4; the combustion of pyrolysis combustible gas provides energy for the furnace temperature, and the furnace temperature is precisely controlled to the second temperature T2=T1+[0, 300]℃ by controlling the oxygen concentration and gas volume of the auxiliary combustion gas and the mass of combustible material brought in by electronic waste. A reduction reaction occurs in rotary kiln 1, and the "oxygen-deficient combustion heating" of pyrolysis combustible gas and the "reduction of unburned metal oxides" are carried out simultaneously. A flue gas composition detector is installed at the flue gas outlet of rotary kiln 1 to monitor O2, CO, and NO in real time. xSO2, CO2, H2, CH X Based on this, the ratio of combustion-supporting gas is adjusted to optimize the reaction. Melting and feeding are synchronized. After the electronic waste undergoes pyrolysis in the furnace, the remaining substances, except for the flue gas, melt into the slag. As the furnace rotates, the slag and crude metal in the furnace come into full contact under mechanical stirring and mixing. The crude metal melt acts as a metal collector, capturing the metal droplets remaining in the slag after the electronic waste's pyrolysis, achieving "metal-non-metal / slag layer" separation and significantly improving the metal recovery rate. Furthermore, the crude metal melt acts as a heat carrier, providing sufficient heat for the pyrolysis of electronic waste, preventing insufficient heat during startup that would cause a large amount of black smoke in the furnace, hindering the self-heating reaction.

[0036] S4. When the slag in rotary kiln 1 reaches the preset slag line height, stop feeding and allow it to settle before discharging the slag. After multiple cycles of feeding, smelting, settling, and slag discharge, when the metal volume in the rotary kiln reaches the target, cast the molten metal into metal ingots. Specifically, when the slag in the furnace reaches the preset height, perform the following steps: stop feeding → reduce furnace speed to settling → adjust the furnace body tilt angle and pour the slag from furnace opening 11 into the slag ladle 8; slag with a higher melting point is assisted in being discharged using a skimming device. After slag discharge, the furnace body returns to the tilted smelting position, and the "feeding-smelting" process is repeated. After multiple cycles of "feeding-smelting-slag discharge," when the metal volume in rotary kiln 1 reaches the target, perform the following steps: final slag discharge → replace the metal casting ingot mold 9 → adjust the furnace body to the casting position and cast the molten metal into metal ingots; the cast metal ingots can be further refined (e.g., refined in a separate furnace, or electrolytically refined to produce high-purity cathode copper).

[0037] S5. The flue gas generated by the rotary kiln is purified by a flue gas purification system. The flue gas sequentially passes through the secondary combustion chamber, quench tower, dry desulfurization tower, bag filter, scrubbing tower, and activated carbon adsorption box before being discharged through the chimney. Specifically, it includes the following steps: The flue gas undergoes secondary combustion and decomposition of organic matter in the secondary combustion chamber 71: the flue gas enters the secondary combustion chamber 71 after passing through the fume hood 5 and the flue duct 6; the "pulse structure" in the secondary combustion chamber enhances turbulence and prolongs the residence time of the flue gas (time ≥ 5s); air / fuel gas is introduced into the secondary combustion chamber, the temperature is raised to 1100℃, and the oxygen content is controlled at 4~12%, so as to completely decompose organic matter such as dioxins, VOCs, and particulate matter.

[0038] Rapid cooling in quench tower 74: Flue gas enters quench tower 74, atomized water comes into countercurrent contact with flue gas, and flue gas is rapidly cooled from 900-1100℃ to 140~180℃ (spanning the 200~400℃ range), inhibiting the resynthesis of dioxins catalyzed by metals such as Cu and Fe.

[0039] In the dry deacidification tower, the flue gas enters the dry deacidification tower (dry deacidification tower 75), where the acidic gas reacts with the lime powder to form a stable solid compound, resulting in a primary deacidification reaction that removes 60%-80% of the acidic gas.

[0040] Dust removal in dust collector 76: Dust-laden flue gas enters a bag filter (dust collector 76), and the dust concentration after collection by the filter bags is <10mg / m³. 3 Dust is collected and returned to the front-end smelting process to improve metal recovery rate.

[0041] Secondary acid removal is performed in scrubbing tower 77: Flue gas enters scrubbing tower 77 and is treated with either a single tower (NaOH spray) or a dual tower series (first-stage NaOH, second-stage Ca(OH)2 spray) to neutralize acidic gases such as HCl. The alkaline mist is then separated by a demister, achieving efficient removal of acidic gases with a removal rate of 98%-99.9%.

[0042] Residual pollutants are adsorbed in activated carbon adsorption box 78: Low acid and low dust flue gas (50~70℃) enters activated carbon adsorption box 78 and adsorbs dioxins, gaseous heavy metals (such as Hg), etc.

[0043] Example 2 This embodiment is based on Embodiment 1. The difference between this embodiment and Embodiment 1 is that: like Figures 2-6 As shown, the flue gas purification system 7 includes a secondary combustion chamber 71, a denitrification reactor 72, a waste heat boiler 73, a quench tower 74, a dry or semi-dry desulfurization tower 75, a bag filter 76, a scrubbing tower 77, an activated carbon adsorption box 78, and a chimney 79, which are connected in sequence by pipes. The secondary combustion chamber 71 is connected to the outlet of the flue 6.

[0044] The flue gas sequentially passes through a secondary combustion chamber 71, a denitrification reactor 72, a waste heat boiler 73, a quench tower 74, a dry or semi-dry deacidification tower 75, a bag filter 76, a scrubbing tower 77, an activated carbon adsorption box 78, and a chimney 79. In the secondary combustion chamber 71, the flue gas undergoes secondary combustion to decompose organic matter; in the denitrification reactor 72, it undergoes denitrification; in the waste heat boiler 73, it recovers waste heat; in the quench tower 74, it undergoes quenching; in the dry or semi-dry deacidification tower 75, it undergoes rapid cooling; in the dust collector 76, it undergoes deacidification; and in the scrubbing tower 77, it adsorbs residual pollutants in the activated carbon adsorption box 78. Finally, the flue gas is introduced into the chimney 79 by an induced draft fan for emission.

[0045] Denitrification in denitrification reactor 72: High-temperature flue gas enters the SNCR denitrification reactor (denitrification reactor 72), and a reducing agent (ammonia / urea solution) and NO are injected. x Reaction; NO at flue gas outlet x The detector adjusts the amount of reducing agent injected in real time to ensure NO levels are within acceptable limits. xMeets the standard.

[0046] Waste heat is recovered in waste heat boiler 73: flue gas with a temperature of 850~1200℃ after denitrification enters waste heat boiler 73, exchanges heat with water, and the flue gas temperature drops to 450~550℃; the produced saturated steam is used for power generation, heating or chemical raw materials.

[0047] The following are specific embodiments provided in this application: Example 3 Taking the processing of copper-containing electronic waste (waste circuit PCBs) as an example, the specific implementation method is explained as follows: Waste PCB (computer / mobile phone motherboard, containing 15~25% copper, 25~35% resin, and 20~30% glass fiber) → Shred to 20~30mm → Sorting out large pieces of metal, with a moisture content of ≤5%.

[0048] (a) Operating parameters of the equipment Rotary furnace 1 is selected from TBRC (top-blown rotary converter or Kaldo furnace): effective volume is 1m³. 3 The rotation speed is 0~15 r / min (0.5 r / min when melting crude metal, 5~15 r / min when smelting, and 0 r / min when settling and slag removal). Metering and feeding assembly 3: includes one set each of electronic waste bin and auxiliary material bin (metering bin group 31), with a metering accuracy of ±0.5% and an electronic waste feeding rate of 0.3~0.6t / h; Multi-channel combustion gun 4: natural gas pressure 0.3~0.5MPa, oxygen (oxygen volume fraction 99%) pressure 0.4~0.6MPa; during the start-up and heating stage, the volume ratio of fuel gas to oxygen-enriched air is 1:2, and the furnace temperature of rotary kiln 1 rises to 50°C above the copper melting point (1083°C) (i.e., T1 is 1133°C). Flue gas purification system 7: The secondary combustion chamber 71 adopts a pulse-type secondary combustion chamber: the flue gas residence time is 3s, the temperature is 1000℃, and the oxygen content is 8%; 74 quench tower: outlet flue gas temperature is 160℃; Dry desulfurization tower 75: Dry lime powder is sprayed into the dry desulfurization tower to react with acidic gas to generate solid salt; Dust collector 76 is preferably a bag dust collector: the filtration velocity is 0.8m / min, and the collected dust is returned to the TBRC furnace for reuse. Scrubbing Tower 77: A dual-tower series washing method is used, with one scrubbing tower using a 10% NaOH solution as the detergent and the other scrubbing tower using an 8% Ca(OH)2 solution as the detergent. Activated carbon adsorption box 78: Activated carbon filling amount 2-3m³ 3 .

[0049] (II) Implementation of the process Charging and Furnace Start-up: When the TBRC furnace is cold, it is moved to the vertical charging position and 0.3t of crude copper blocks (crude metal blocks) are added through the charging device 2. Then it is moved to the inclined smelting position and the multi-channel combustion gun 4 is inserted. The multi-channel combustion gun 4 introduces natural gas and oxygen into the TBRC furnace and ignites it to raise the temperature, so that the crude copper blocks are melted into copper melt (crude metal melt) and the furnace temperature is raised to 50°C above the copper melting point (1083°C) (i.e., T1 is 1133°C).

[0050] Electronic waste smelting: After the furnace temperature stabilizes at 147℃ above T1 (i.e., T2=1280℃), the metering and feeding component 3 adds copper-containing electronic waste at a rate of 300kg / h, while oxygen-enriched air is injected at the same time; the furnace temperature is maintained by combustion and reduction of pyrolysis gas, and the amount of oxygen-enriched air is adjusted by the flue gas composition detector to maintain a weak reducing atmosphere in the furnace.

[0051] Slag removal and casting: After smelting for 4 hours, the slag volume reaches the standard. Stop feeding → reduce furnace speed and let stand → adjust the tilt angle to remove slag. After repeating "feeding-smelting-slag removal" 3 times, the copper melt in the furnace reaches 4-5t. After the last slag removal, cast the copper into the metal casting mold 9 to form crude copper ingots (each ingot weighs about 1t), which will be used for subsequent anode refining and electrolytic refining for further purification. 0.3t of copper melt is reserved in the furnace for the next batch of furnace start-up melt.

[0052] (III) Flue Gas Treatment Process Secondary combustion: The flue gas enters the pulse-type secondary combustion chamber (secondary combustion chamber 71) through the water-cooled fume hood (fume hood 5) and stays for 3 seconds; preheated oxygen-enriched air is introduced into the secondary combustion chamber 71 to assist combustion, and the temperature is controlled at 1000℃ to ensure the complete decomposition of residual dioxins, VOCs and other organic matter. Rapid cooling: Flue gas at 1000℃ is cooled to 180℃ by quench tower 74, rapidly crossing the 200~400℃ range to inhibit dioxin resynthesis; Dry desulfurization tower: Dry lime powder is sprayed into the dry desulfurization tower to react with acidic gases and generate solid salts; Bag filter: The filtration velocity is 0.8 m / min, and the collected dust is returned to the TBRC furnace for reuse. Scrubbing towers: A dual-tower series washing method is adopted. The detergent in one washing tower is a 10% NaOH solution, and the detergent in the other washing tower is an 8% Ca(OH)2 solution. Deep purification: Activated carbon adsorption box 78 (activated carbon filling amount is 2-3m³) adsorbs residual dioxins and heavy metals, and the purified flue gas is discharged through the chimney. Flue gas purification effect: After treatment, the concentration of pollutants emitted from the flue gas is: dioxins < 0.1 ng I-TEQ / Nm³, NO x <50mg / Nm³, HCl <10mg / Nm³, particulate matter <5mg / Nm³, Hg <0.05mg / Nm³, meeting the "Standard for Pollution Control of Hazardous Waste Incineration" (GB18484-2020) and stricter local standards.

[0053] Through practical examples, it has been verified that a 1m³ TBRC furnace for processing waste PCBs, along with its accompanying deep flue gas purification treatment, can effectively address the pain points of traditional waste PCB processing and has the following advantages: Highly efficient and comprehensive metal recycling: Copper recovery rate ≥99.5%, heavy metals such as gold, silver, lead, and tin can be enriched in crude copper alloy ingots (avoiding loss with flue gas), and subsequent refining can be carried out in a classified manner to maximize the utilization of valuable metals in waste PCBs; avoiding the smelting of electronic waste at the melting point of crude metals, insufficient smelting temperature, large amount of PCBs cannot be fully decomposed and carbonized, the resulting high-silicon slag mixed carbides have extremely high viscosity at low temperature, causing the reaction to be unable to proceed smoothly or even stop, resulting in incomplete separation of metal and slag, long decarburization time in slag, and severe metal oxidation during the decarburization process, completely deviating from the original intention of high metal recovery rate of low temperature smelting.

[0054] High resource utilization rate: Resins and other organic matter in PCB boards are cracked and burned in a controlled proportion in the smelting furnace. The calorific value contained in the organic matter brought in by electronic waste is converted into the heat required for smelting in the furnace to maintain the self-heating reaction in the furnace, resulting in very low production costs. At the same time, the reducing atmosphere in the furnace is maintained to prevent the liquid metal from oxidizing at high temperatures. The metal recovery rate is high, and there are no valuable metals to be recovered in the slag, nor are there any heavy metal elements to be leached. It can be directly and safely landfilled.

[0055] Environmental compliance with no secondary pollution: After multiple purification processes, the levels of dioxins (<0.07ngI-TEQ / Nm³), HCl (<3mg / Nm³), and mercury (<0.01mg / Nm³) in the flue gas are far below national standards; the captured dust is recycled, and there are no valuable metals to be recovered from the slag, nor are there any heavy metal elements that can be leached out, so it can be directly and safely landfilled, with no pollutant leakage throughout the entire process; Simple to operate and high added value: The process flow is continuous (feeding-smelting-slag removal-casting); the crude copper alloy ingots produced are quickly converted into crude copper anode plates with a purity of over 98.5% after anode refining, which can be directly sent for electrolytic refining to quickly recover funds; Example 4 2m of waste copper wire 3 TBRC furnace smelting recovery and flue gas treatment process description and implementation method: Waste copper wires (scrap cables, BV wires, motor enameled wires, copper-containing plastics that cannot be separated, etc.), containing 80-96% copper (T2 / T3 copper core), 3-15% insulation layer (PVC / rubber), and a small amount of oxide impurities; cut into 8-15cm short sections using a hydraulic shearing machine (no need to peel off the insulation layer), ensuring uniform feeding.

[0056] (a) Operating parameters of the equipment Rotary furnace 1 is a TBRC furnace with an effective volume of 2m³. 3 ; Metering and feeding assembly 3: includes 2 waste copper wire hoppers and 4 auxiliary material hoppers (metering hopper group 31), which simultaneously meter and feed materials; the metering accuracy is ±0.5%, and the waste copper wire feeding rate is 2~4t / h; Multi-channel combustion lance 4: Oxygen-fuel ratio = 2 at start-up; during smelting, the oxygen-fuel ratio is adjusted to >2, using organic matter decomposed from raw materials as fuel to meet the heating needs of the smelting reaction. The TBRC furnace temperature rises to 117°C above the copper melting point (1083°C) (i.e., T1 is 1200°C). Flue gas purification system: The secondary combustion chamber 71 uses a pulse-type secondary combustion chamber: temperature 950~1050℃, flue gas residence time ≥3s, and oxygen content 7~8%. Rapid cooling: Flue gas at 1050℃ is cooled to 160℃ by quench tower 74, which inhibits the resynthesis of dioxins by crossing the 200~400℃ range; Dry or semi-dry deacidification tower 75: Dry lime powder is sprayed into the dry or semi-dry deacidification tower to react with acidic gas to generate solid salt, and the outlet temperature is 150~170℃. Dust collector 76 is preferably a bag filter: filtration velocity is 1m / s, outlet dust concentration is ≤5mg / Nm³; settled dust is collected and returned to the TBRC furnace for smelting; Scrubber 77: A single-tower scrubbing method is used. The scrubbing agent in the spray scrubbing tower is a 15% (w / w) NaOH solution. After scrubbing, the HCl content is ≤5 mg / Nm³. Activated carbon adsorption box 78: The activated carbon filling amount is 3m³. After activated carbon adsorption, the dioxin content in the flue gas is ≤0.08ngI-TEQ / Nm³.

[0057] (II) Implementation of the process Adding fuel and starting the furnace: When the TBRC furnace is in a cold state, it is moved to the vertical feeding position and a 0.5t crude copper block (crude metal block) is added through the feeding device 2. Then it is moved to the inclined smelting position, and a multi-channel combustion gun 4 is inserted. Natural gas and oxygen are introduced to ignite and heat up to about 1200℃, so that the crude copper block is melted into copper melt (crude metal melt). Continuous smelting: The furnace temperature is stabilized at T2=1250~1300℃. The metering and feeding component 3 adds the sheared waste copper wire at a rate of 2~4t / h, and simultaneously adds 50kg / h of quartz sand and 30kg of limestone. Natural gas is shut off, and only oxygen-enriched air (oxygen content of 30~99%) is injected. The furnace temperature is maintained by combustion of the insulation layer cracked gas (CH4, C2H4). The TBRC furnace rotates at a speed of 10 r / min. The copper conductor core melts and is incorporated into the melt. The insulation layer is completely decomposed, and impurities and slagging agents form slag.

[0058] Slag removal and casting: After smelting for 4-6 hours and the amount of slag reaches the standard: stop feeding → reduce furnace speed and let stand for 10-20 minutes → adjust the tilt angle and manually assist in slag removal (single slag amount is 300-500 kg, copper content ≤0.05%). After slag removal, crude copper is cast into crude copper anode plates (350 kg per piece, 97-99% purity) for subsequent electrolysis to obtain high-purity cathode copper; 0.5 t of liquid metallic copper is reserved in the furnace for use as the start-up melt for the next batch.

[0059] (III) Flue Gas Treatment Process Secondary combustion: The flue gas enters the pulse-type secondary combustion chamber through the water-cooled fume hood (fume hood 5). After secondary combustion, the flue gas temperature is 1050℃. Under this high temperature condition, the VOCs and dioxin precursors generated by the decomposition of the insulation layer are completely decomposed. The flue gas residence time is 4s to ensure that the harmful substances are completely decomposed. Rapid cooling: Flue gas at 1050℃ is cooled to 160℃ by a quench tower at 75℃, which inhibits the resynthesis of dioxins by crossing the 200~400℃ range; Dry or semi-dry deacidification tower: Dry lime powder is sprayed into the dry or semi-dry deacidification tower to react with acidic gases and generate solid salts; Dust removal and acid removal: Bag filter collects dust (for recycling), and a single scrubbing tower sprays 77 times to remove HCl (concentration 10~15%). Deep purification: The activated carbon adsorption box (with an activated carbon filling of 2~3m³) adsorbs residual dioxins and heavy metals. The purified flue gas is then discharged through a chimney (compliance indicators: dioxins <0.08ngI-TEQ / Nm³, HCl <5mg / Nm³, particulate matter <3mg / Nm³).

[0060] Through examples, it has been verified that a TBRC furnace with an effective volume of 2m³ has the following advantages in processing waste copper wires; High-efficiency energy recycling: 50-100% of natural gas is replaced by cracked gas in the insulation layer, reducing overall energy consumption by 30-50%; Stable copper recovery rate: With melt trapping and interface update design, the copper recovery rate is ≥99.9%, and the purity of the anode plate meets the requirements of electrolytic refining. Reliable environmental compliance: The targeted purification process ensures that flue gas pollutants are far below national standards, with no risk of secondary pollution.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for recycling and processing electronic waste, characterized in that, Includes the following steps: S1. Add a pre-set weight of coarse metal blocks into the rotary kiln; S2. The rotary kiln is heated to melt the crude metal block into a crude metal melt. S3. Continuously add electronic waste and smelting auxiliary materials with controllable quality and composition into the rotary kiln, and introduce oxygen-enriched air or pure oxygen with controllable oxygen ratio. S4. When the slag in the rotary kiln reaches the preset slag line height, stop feeding and let it stand before discharging the slag. After multiple cycles of feeding, smelting, standing, and slag discharge, when the metal volume in the rotary kiln reaches the standard, cast the molten metal into metal ingots. S5. The flue gas generated by the rotary kiln is purified by the flue gas purification system.

2. The electronic waste recycling and processing method as described in claim 1, characterized in that, The flue gas generated by the rotary kiln is purified by a flue gas purification system, including the following steps: The flue gas passes sequentially through a secondary combustion chamber, a quench tower, a deacidification tower, a dust collector, a scrubbing tower, an activated carbon adsorption box, and a chimney. In the secondary combustion chamber, the flue gas undergoes secondary combustion to decompose organic matter. In the quench tower, it is rapidly cooled. In the deacidification tower, it undergoes primary deacidification. In the dust collector, it undergoes dust removal. In the scrubbing tower, it undergoes secondary deacidification. In the activated carbon adsorption box, it adsorbs residual pollutants. Finally, it is discharged through the chimney.

3. The electronic waste recycling and processing method as described in claim 2, characterized in that, The flue gas enters the secondary combustion chamber, where unburned materials continue to burn. The temperature of the secondary combustion is controlled at 850-1200℃, the oxygen content is 4-12%, and the flue gas residence time is not less than 3 seconds.

4. The electronic waste recycling and processing method as described in claim 2, characterized in that, When the flue gas is rapidly cooled in the quench tower, the temperature drops from 850-1200℃ to 140-180℃. A deacidifying agent is sprayed into the deacidification tower to neutralize and deacidify the acidic gas. The gas is then collected by a dust collector, achieving neutralization and deacidification while inhibiting dioxin resynthesis. Subsequently, the flue gas enters the alkaline washing deacidification tower for further deep deacidification. Finally, the flue gas enters the activated carbon adsorption box to adsorb residual pollutants, completing deep purification.

5. The electronic waste recycling and processing method as described in claim 1, characterized in that, The crude metal is one or more of copper, iron, aluminum, zinc, lead, and tin, and the crude metal melt formed by its melting serves as a heat carrier and metal collector.

6. The electronic waste recycling and processing method as described in claim 1, characterized in that, In step S2, the rotary kiln is heated to a first temperature T1 > T0, where T0 is the melting point of the valuable metals in the electronic waste; And / or in step S3, the furnace temperature is controlled to be a second temperature T2 ≥ T1, where T1 is the first temperature for heating.

7. An electronic waste recycling and processing device, characterized in that, For implementing the electronic waste recycling and processing method as described in any one of claims 1-6, the electronic waste recycling and processing apparatus comprises: Rotary furnaces are used to melt crude metal blocks and electronic waste. A feeding device is used to add a predetermined weight of coarse metal blocks into the rotary kiln; A metering and feeding assembly is used to add a preset weight of electronic waste and smelting auxiliary materials into the rotary kiln; A multi-channel combustion lance is used to introduce one or more of fuel, air, oxygen, or oxygen-enriched air into the rotary kiln. A fume hood, the inlet of which faces the furnace opening of the rotary kiln; The flue connects the fume hood to the flue gas purification system.

8. The electronic waste recycling and processing device as described in claim 7, characterized in that, The rotary kiln is a top-blown rotary kiln. The rotary kiln can be tilted to adjust the furnace opening to a vertical feeding position, an inclined smelting position, or a slag discharge / casting position with the furnace opening lower than the furnace bottom. The vertical feeding position is equipped with the feeding device, and the inclined smelting position is equipped with the metering feeding assembly, the multi-channel combustion gun, the fume hood, and the flue.

9. The electronic waste recycling and processing device as described in claim 8, characterized in that, It also includes a slag ladle and a metal casting ingot mold. The slag ladle and the metal casting ingot mold are provided at the slag discharge / casting position. The slag ladle is used to collect slag waste, and the metal casting ingot mold is used to collect molten metal.

10. The electronic waste recycling and processing device as described in claim 8, characterized in that, The flue gas purification system includes a secondary combustion chamber, a quench tower, a deacidification tower, a dust collector, a scrubbing tower, an activated carbon adsorption box, and a chimney, all connected in sequence by pipelines.

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