Method for extracting common and precious metals from discarded circuit boards

Abstract

To provide an environmentally friendly method for recycling metallic and non-metallic components from printed circuit boards (PCBs) while minimizing greenhouse gas emissions and without using processes potentially harmful to the environment. The method includes the steps of shredding PCBs, pulverizing the shredded PCBs to produce a micronized powder, removing plastics and epoxy resins from the micronized powder, leaching, precipitating and recovering Al, Fe, Zn, Ni, Cr, Cu, Au, Ag and Pd from the micronized powder and producing a filtrate from which Cu can be recovered. The solid product of the method is a concentrate of precious metals.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 364131, filed May 4, 2022, the contents of which are incorporated by reference in their entirety.

[0002] The present invention provides an environmentally friendly method for recycling metallic and non-metallic components from printed circuit boards. [Background technology]

[0003] The amount of electronic waste (e-waste) is increasing by approximately 2Mt / year worldwide. Globally, approximately 53.6Mt of e-waste was generated in 2019 alone, and it is estimated that this amount will exceed 75Mt by 2030.

[0004] The global volume of e-waste was 53.6 Mt in 2019, of which only 17.4% was collected. This volume is expected to double by 2050. The electronics industry consumes 7% of the world's total Au production, or $63 billion per year. Canada generates 741 kt of e-waste annually. E-waste contains many valuable resources, but is also a harmful pollutant. Printed circuit boards make up about 3% of e-waste by weight and contain common and precious metals, plastics, fiberglass, ceramics, and epoxy resins.

[0005] Printed circuit boards (PCBs) have an insulating substrate, typically made of epoxy resin and fiberglass, and a thin layer of copper foil covered with a layer of colored solder masking that insulates the copper traces. The conductive paths of the circuit are made of copper. PCBs should be properly disposed of when they reach the end of their life.

[0006] Precious metals extracted from discarded electronics represent a significant source of revenue, but are difficult to recover due to the complexity of their material composition.

[0007] The traditional method used to recover precious metals from printed circuit boards is incineration before metal extraction by pyrometallurgy or hydrometallurgy. Such operations result in the formation of toxic pollutants such as furans, dioxins and halogenated compounds. Most of this waste is disposed of in developing countries. Pyrometallurgy produces large amounts of greenhouse gas emissions. Also, toxic chemicals such as dioxins, furans, bromine and chlorine compounds are released during the pyrometallurgy process. Volatile metals such as Pb, Ga, Sb and As are released into the atmosphere during this process.

[0008] Hydrometallurgy is described as a method for selective extraction of metals from electronic waste by aqueous solutions, the principle of which is based on the different solubilities of tin, lead and copper in different concentrations of acid or base.

[0009] Electronic components are removed from printed circuit boards (PCBs) by dissolving the solder using acid or acid and oxidants. Ultrasonic assisted hydrometallurgy has been proposed to recover common and precious metals.

[0010] US Patent No. 5,399,633 discloses an apparatus and method for separating precious and base metals from electronic waste using hydrochloric acid and an oxidizer, dissolving solder and recovering gold flakes. After a grinding process, the copper contained in the bare circuit board is dissolved with a mixture of hydrochloric acid and hydrogen peroxide. The electronic components are pulverized separately and exposed to an acid / oxidizer solution mixture to dissolve the metals. The metals are then recovered in an electrolytic bath, i.e. precipitated.

[0011] Patent Document 2 proposes an apparatus and method for stripping solder metal and removing electronic components from PCBs by mechanical and / or thermal processes. The metals that form the solder are dissolved by a combination of acid and oxidizing agent.

[0012] Common and precious metals can also be dissolved from crushed material in a single leaching step using a mixture of acid, oxidizing agent and iodine (see US Pat. No. 5,333,633). [Prior art documents] [Patent documents]

[0013] [Patent Document 1] U.S. Pat. No. 8,551,212 [Patent Document 2] U.S. Pat. No. 9,731,368 [Patent Document 3] US Patent Publication No. 20170079146 Summary of the Invention [Problem to be solved by the invention]

[0014] There is a need to provide a means for extracting base metal and non-metallic components from printed circuit boards without using processes that are potentially environmentally harmful. [Means for solving the problem]

[0015] The present invention provides a method for recycling metallic and non-metallic components from printed circuit boards (PCBs) having solder metal and at least one copper layer, comprising the steps of: shredding the PCBs; atomizing the shredded PCBs to produce fine powder; removing plastic and epoxy resin from the fine powder; leaching, precipitating and recovering Al, Fe, Zn, Ni, Cr, Au, Ag and Pd from the fine powder; and leaching the peeled components containing Cu and preparing a filtrate in which Cu has been precipitated.

[0016] In another embodiment, the PCBs are chopped into particles having a size of 5-50 mm.

[0017] One embodiment involves washing the fine powder with caustic soda or an extractant to remove epoxy resin from the shredded PCBs and expose the solder metal and at least one copper layer of the shredded PCBs; treating the shredded and exposed PCBs in a solder leaching reactor to dissolve the solder metal and produce a solid phase and a leachate containing the recovered solder metal.

[0018] In one embodiment, the caustic soda is 1-10M NaOH, or the extractant is KOH or ammonium hydroxide.

[0019] A further embodiment is where the solder metal is dissolved in a solution of sulfonic acid under the influence of an oxidizing agent in the solder leaching reactor.

[0020] In another embodiment, the sulfonic acid is methanesulfonic acid (MSA).

[0021] In one embodiment, the oxidant is hydrogen peroxide, pure oxygen, enriched air, air, ozone, nitric acid, oxone, ammonium chlorite, ammonium chlorate, ammonium iodate, sodium hypochlorite, potassium hypochlorite, ammonium hypochlorite, sodium perchlorate, potassium perchlorate, or ammonium perchlorate.

[0022] A further embodiment is where the solder metal recovered is Sn, Pb, Al, Ag, Cu, Fe, or combinations thereof.

[0023] In one embodiment, the method further comprises recovering ferromagnetic materials comprising Fe, Ni and Co by magnetic separation of the fine powder.

[0024] In one embodiment, the solid phase is atomized to a powder of less than 2 mm.

[0025] In one embodiment, the fine powder is exfoliated at a temperature of about 90 to 150° C. using a hot extractor.

[0026] In another embodiment, the hot extraction agent is Dimethyl sulfoxide ( DMSO ) , Dimethylformamide ( DMF ) or ethylene glycol N-Methyl-2-pyrrolidone ( NMP ) It is a combination of an extractant and a catalyst.

[0027] In a further embodiment, the method further comprises the step of recovering the hot extractant from the liquid phase by vacuum stripping.

[0028] In another embodiment, the stripping member is treated with H2SO4 at a temperature of about 50-70°C.

[0029] In one embodiment, the fine powder is thermally oxidized using an oxidizing agent in a heating reactor at a temperature of 400 to 950° C. to remove plastic and epoxy resin and generate a gas phase.

[0030] In an additional embodiment, the oxidant is O2, air, or enriched air containing 21-100% O2.

[0031] In one embodiment, the shredded PCBs are treated in a reactor.

[0032] In one embodiment, the method further comprises dissolving the epoxy cleaned from the shredded PCBs to regenerate the caustic soda or the extractant.

[0033] In one embodiment, the Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, Pd and inert metals precipitated and recovered from the fine powder are treated with H2SO4 to produce a liquid phase containing dissolved Al, Zn, Fe, Ni, Cr and trace amounts of other common metals, and a solid phase containing Cu, trace amounts of other common metals, Au, Ag, Pd and inert metals.

[0034] In one embodiment, Al, Zn, Fe, Ni, Cr, and trace amounts of other common metals are precipitated from the liquid phase in a selective precipitation reactor.

[0035] A further embodiment is to leach the Cu and the remaining ordinary metals in a second leach reactor.

[0036] A further embodiment is to leach Cu using H2SO4 and a second oxidant.

[0037] In another embodiment, the second oxidant is hydrogen peroxide, pure oxygen, enriched air, air, ozone, nitric acid, oxone, ammonium chlorite, ammonium chlorate, ammonium iodate, sodium hypochlorite, potassium hypochlorite, ammonium hypochlorite, sodium perchlorate, potassium perchlorate, or ammonium perchlorate.

[0038] In one embodiment, the Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, Pd and inert metals precipitated and recovered from the fine powder are treated with H2SO4 to produce a liquid phase containing dissolved Al, Fe, Zn, Ni, Cr, and other common trace metals, and a solid phase containing Cu, other common trace metals, Au, Ag, Pd and inert metals.

[0039] Another embodiment is to precipitate Al, Fe, Zn, Ni, Cr, and other trace common metals from the liquid phase in a selective precipitation reactor.

[0040] A further aspect is that the Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, Pd and inert metals precipitated and recovered from the fine powder are treated with H2SO4 and an oxidizing agent in a single reaction step to produce a liquid phase containing dissolved Al, Fe, Zn, Ni, Cr, Cu, and a solid phase containing Au, Ag, Pd and inert metals.

[0041] A further embodiment is that the Cu is deposited in a reactor with thorough mixing.

[0042] Another embodiment is to precipitate Cu with acetone, methanol, or a combination thereof.

[0043] Another embodiment is to recover the Cu by diffusion penetration or electrowinning.

[0044] In one embodiment, the method further comprises recovering residual metals after electrodeposition of Cu.

[0045] In one embodiment, the method further comprises the step of recovering the residual metal after depositing Cu by diffusion penetration.

[0046] A further embodiment is where the residual residues are Au, Ag and Pd.

[0047] In another embodiment, the recovered residual metals are further extracted using sodium hypochlorite.

[0048] In one embodiment, the recovered residual metals are used in environmentally friendly operations, such as the CLEVR process. TM The extraction is carried out using the following formula:

[0049] Another embodiment is that the PCBs are single layer, double layer or multi-layer. Effect of the Invention

[0050] The present invention provides an environmentally friendly method for recycling metallic and non-metallic components from printed circuit boards that involves mechanical and hydrometallurgical processes to selectively extract base metals and non-metallic components from printed circuit boards (PCBs) without the use of aqua regia, cyanide techniques, or potentially environmentally harmful processes such as pyrometallurgy, resulting in minimal greenhouse gas emissions and no release of toxic compounds. [Brief description of the drawings]

[0051] Reference will now be made to the accompanying drawings, in which:

[0052] [Figure 1] FIG. 1 shows a flow diagram of a general method for recycling PCBs in an embodiment.

[0053] [Diagram 2] FIG. 2 shows a flow diagram of a general method for PCB recycling involving a thermal oxidation step in another embodiment.

[0054] [Diagram 3] FIG. 3 shows the results of heat treatment of the printed circuit board.

[0055] It is noted that throughout the accompanying drawings, like features are numbered the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] PCBs are made up of successive layers of different materials, and in simple terms they are made up of three main layers in a sandwich structure. 1. Some fiberglass fabrics have 2.One or more copper layers; 3. Bromine (Br)-containing substances (e.g., Polybrominated diphenyl ethers ( PBDE ) , Tetrabromobisphenol ( TBBPA ) , Hexabromocyclododecane ( HBCD ) , Polybrominated biphenyls ( PBB ) ) a flame-retardant bonding layer consisting of a reinforced epoxy resin layer; 4. An epoxy layer (masking) applied to the surface of the board to protect the contacts and sometimes the electronic components. It is something that is formed.

[0057] Depending on the number of copper (Cu) layers, PCBs can be single-layer, double-layer, or multi-layer.

[0058] A PCB is a support for electronic elements (resistors, capacitors, diodes, integrated circuits, etc.). The present invention provides a method for recycling PCBs that have electronic components soldered to them. As mentioned above, the composition and structure of PCBs vary depending on the electronic device.

[0059] Precious metals (PM) are used in microprocessors and electrical contacts. Contacts are covered with a thin film of Ag or Sn on Cu foil to prevent oxidation. Ag is also used on the capacitor surface. Pb, Bi, Sn, and Ag are used in welds.

[0060] As follows, the process of the present invention provides an environmentally friendly means for extracting epoxy resins, bromine compounds, and common metals such as Cu, Pb, Sn, Al, Fe, Co, and Zn. At the end of the process, the raw material is prepared for recovery of Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, and Pd. The process includes coarse shredding, masking removal, solder leaching, pulverization, stripping, acid leaching, oxidative leaching, precipitation, and electrolytic recovery of metals.

[0061] In one embodiment, this method allows the epoxy resin to be extracted and the bromine compounds removed without incineration. Thermogravimetric testing showed that the bromine compounds (TBBPA) did not decompose up to 150° C. and remained attached to the extracted epoxy resin.

[0062] The term "printed circuit board" or "PCB" means an electronic circuit consisting of a thin strip of conductive material, such as copper, etched from a layer affixed to a flat insulating sheet called a printed circuit board, on which integrated circuits, electronic devices, and other components are mounted.

[0063] The term "shredding" refers to, but is not limited to, an operation of crushing into particles having a diameter of 5 to 50 mm, for example, using a twin-shaft shredder.

[0064] The term "atomization" refers to the operation of reducing the average diameter of a solid to below the millimeter scale.

[0065] The term "leaching" refers to a chemical operation in which any solid components are dissolved into solution using a single extractant or a mixture of extractants.

[0066] The term "flotation" refers to the selective separation of components, typically solids, by exploiting the difference in density between the components and a fluid, typically water.

[0067] As shown in FIG. 1, the method includes a first step 100 of shredding (or shredding) a printed circuit board (PCB) using a shredder or the like to produce pieces of, for example, 5 to 50 mm.

[0068] PCBs are covered on the entire surface with an epoxy layer (masking material) that protects the copper circuitry. This layer has printed thereon information about the electronic components. To make the copper layer usable, this layer must be leached out. During a second step 110, the masking material is treated in caustic soda, 1-10 M NaOH, or in KOH or ammonium hydroxide (i.e. caustic wash) to remove the epoxy resin. The reaction temperature is appropriately selected (e.g. 50-120°C).

[0069] The reaction is carried out in a heated reactor with thorough mixing. The molten epoxy resin is separated from the caustic liquid phase in a separator (step 111). In an embodiment, the molten metal is allowed to precipitate and The extractant can now be regenerated (Step 121 in Figure 2)The solution is recycled to the leaching step 110. The solids are processed in a solder leaching reactor (step 120). A typical alloy composition is 63% Sn / 37% Pb. The extractant for this operation is sulfonic acid, which dissolves Sn and Pb by the effect of an oxidizing agent. Such an acid can be, for example, any sulfonic acid, but is preferably methanesulfonic acid (MSA). The oxidizing agents include, but are not limited to, hydrogen peroxide, pure oxygen, air, ozone, nitric acid, oxone, ammonium salts of chlorite or chlorite or iodate, sodium or potassium or ammonium hypochlorite, or sodium or potassium or ammonium perchlorate. Sn, Pb and / or Al are recovered at this stage. The MSA solution also contains silver as well as small amounts of copper and iron.

[0070] After solid-liquid separation and washing, the solid phase is pulverized to a powder of 2 mm or less (step 130). Ferromagnetic materials, including Fe, Ni, and Co, can be separated by magnetic separation (step 140).

[0071] The micronized composite material is then mixed with, for example, DMSO, DMF, or ethylene glycol and an extractant (NMP) and a catalyst (e.g., 1,5,7-Triazabicyclo 4.4.0 Dec-5-ene The composite is then exfoliated (step 150) using a high temperature extractant such as a combination of epoxy resin and ethylene glycol. This reaction results in the complete cleavage of the composite and the exposure of the metal. The composite is thoroughly mixed in a reactor and heated to 90-150°C. After 90 minutes, the epoxy resin is in liquid phase and the glass fibers are completely exfoliated. The metal is insoluble in the extractant. The extractant is regenerated by vacuum distillation in step 151.

[0072] After stripping, the reactor contents are filtered and washed. In step 160, the atomized stripped PCBs are treated with H2SO4 in a thoroughly stirred reactor. At this stage, most of the Al and the remaining Zn and Sn are dissolved at 50-75°C.

[0073] After the reaction, the reactor contents are decanted and further filtered. The liquid phase is transferred to a selective precipitation reactor (step 161). Al and other metals (e.g., Zn, Co, Sb) are selectively precipitated with NaOH or Ca(OH)2.

[0074] The solids from step 160 are transferred to a second leaching reactor (step 170) where leaching is carried out at 50-75°C using H2SO4 and an oxidizing agent. The oxidizing agent can be, but is not limited to, hydrogen peroxide, pure oxygen, air, enriched air, ozone, nitric acid, oxone, ammonium salts of chlorite, chlorate or iodate, sodium or potassium or ammonium hypochlorite, and sodium or potassium or ammonium perchlorate. After this leaching step, 95% of the Cu and 95% of the other common metals are removed from the atomized PCBs. The filtrate from the Cu leaching reactor is precipitated (step 171) with acetone or methanol in a thoroughly mixed reactor. This operation is called SDC (solvent displacement crystallization), which reduces the solubility of inorganic solutes with organic extractants. Polar extractant molecules have a higher affinity for water molecules than metal ions. When combined with water molecules, the metals are less soluble, resulting in precipitation. The presence of organic extractants in H2SO4 / H2O aqueous solutions reduces the dielectric constant by replacing hydrogen bonds between water molecules with alcohol-water type bonds. Extractant deposition of copper may also be replaced by diffusion infiltration into metallic iron. The remaining metal is recovered by electrodeposition or precipitation with NaOH or KOH or Ca(OH)2. 。

[0075] After the reaction, the reactor contents are decanted and further filtered. Au, Ag, and Pd are recovered using solid phase purified ordinary metals and epoxy resin. (Step 180) .

[0076] In another embodiment, the method of the present invention includes a thermal oxidation process to remove all plastic materials and epoxy resins in a PCB. (Step 150b)The term "thermal oxidation" refers to reaction with oxygen at temperatures between 400 and 950 °C. This operation is an alternative to epoxy resin removal using organic extractants. After thermal oxidation, there is a total oxidation step in which all hydrocarbons in the gas phase are oxidized to carbon dioxide and water. (Step 151b) followed by. The water produced is then condensed and the heat is recovered in a heat exchanger. In the alkaline gas scrubber, the carbon dioxide fraction is fixed as sodium carbonate and sodium bicarbonate. Fluorine, chlorine and bromine are present in the liquid phase as molecular halogens and hydrohalic acids. In another embodiment, fluorine is recovered as CaF2 by reaction with CaO.

[0077] After removing the organic components of the thermal oxidation tail gas, the halogenated acids are dissolved and the CO2 fraction is fixed as bicarbonate in an alkaline gas scrubber (step 152). "Gas scrubber" means any device designed to scrub a gas stream with an alkaline solution to remove or capture specific components.

[0078] The alkaline agent may be NaOH, CaOH, or KOH at a concentration of 1-10 M. The remaining CO2 is vented to the atmosphere and the precipitate formed during the reaction is removed by filtration. NaCl and NaBr are reused for precious metal extraction.

[0079] Fluorine is removed as CaF2 by mixing the liquid exiting the gas scrubber with CaO or Ca(OH)2. 。

[0080] In another embodiment, the thermal removal of the plastic is followed or preceded by an acid leaching process (e.g., 17 in FIG. 2) of Cu and other common metals (Fe, Al, Zn, Co, Ni, etc.). 0 This can be achieved by the following:

[0081] In another embodiment, the precious metal does not include powdered and exfoliated common metal. Discarded printed circuit boards ( WPC )The next process is, but is not limited to, the CLEVR Process, which has the advantage of being able to be carried out in a closed system, and which can recycle all chemicals in the circuit and properly use seawater. TM It is recovered using

[0082] Depending on the nature of the raw material, pre-treatment may be required prior to the extraction step.

[0083] If the oxidized mineral contains base metals to be recovered, such as copper, a water or acid leaching is carried out before the extraction step. In fact, if the controlled operating conditions of the oxidation result in the formation of mainly copper sulfate, a water leaching can be carried out instead of an acid leaching with sulfuric acid. After filtering the water or acid leaching suspension, the copper can be recovered. EXAMPLES

[0084] (Example 1: Extraction of solder metal) Small scale tests were carried out using 100 g of chopped printed circuit boards of 25 mm diameter for 120 min using 3.5 M methanesulfonic acid and 0.5 M hydrogen peroxide as extractants, at room temperature and a liquid / solid ratio of 1 / 10 kg / l.

[0085] The results are shown in Table 1. [Table 1]

[0086] After the leaching process, the solids were separated and washed with 200 ml of distilled water. The metals in the leachate and in the water were analyzed by inductively coupled plasma (ICP).

[0087] To assess the leachable metals on the printed circuit board strips, the solids were then treated with Aqua Regia at 90°C for 4 hours, at which point all metals were measurably dissolved. The sum of the metals in the methanesulfonic acid leachate, rinse water, and Aqua Regia leachate was estimated to represent the total leachable metals on the board strips.

[0088] Thus, the results in Table 1 only account for leachable metal that is not covered with epoxy resin and encapsulated in electronic components. Most of the copper is protected by the epoxy masking material and cannot be leached. For example, in Table 1, only 24% of the available copper was leached by the acid solution.

[0089] (Example 2: Removal of masking material) Solder masking, solder stop masking, or solder resist, is a thin polymeric film that is typically applied over copper to the surface of a printed circuit board to prevent oxidation and short circuits.

[0090] The mounted video card and printed circuit board from the motherboard were chopped into 5 mm diameter pieces and treated with methanesulfonic acid in the same manner as in Example 1 to extract the solder. The electronic device components and printed circuit pieces were treated with a 10% NaOH solution at 90°C for 105 minutes. After the reaction, the copper layer was completely exposed and could be recovered. Table 2 shows the test results. [Table 2]

[0091] (Example 3: Removal of organic matter by heat treatment) Printed circuit board flakes from video cards and motherboards were pulverized to a diameter of less than 1 mm. 102 g of this was placed in a horizontal quartz heater heated to a maximum temperature of 650°C. Pure oxygen was flowed through the heater at a flow rate of 5-10 LPM during the entire test. The concentrations of CO, CO2, and O2 were continuously analyzed with a gas analyzer. The results are shown in Figure 3.

[0092] Oxygen quickly started to react with the organic matter at 160°C, and its concentration decreased. At 550°C, all the oxygen supplied was consumed in the reaction. After 150 minutes, the organic matter that could react had already been exhausted, and the amount of CO2 produced had decreased to zero.

[0093] Total carbon analysis of the treated mixture showed that all plastics and epoxy resins were removed. A weight loss of 34.5% corresponds to the total organic matter of the printed circuit board.

[0094] The results are shown in Table 3. [Table 3]

[0095] (Example 4: Removal of base metals) Printed circuit boards that had been previously shredded, leached with methanesulfonic acid and pulverized to a particle size of less than 1 mm were treated with a sulfuric acid solution and with a sulfuric acid solution and peroxide.

[0096] A sample weighing 780 g treated as above was mixed with 7.8 L of 1M H2SO4 at 50°C for 4 hours. After this first treatment, the sludge was filtered and the solids were subjected to a second leaching treatment with 1.2M H2SO4 and H2O2 at 72°C for 3.5 hours. After filtration, metallic copper was still found in the solids, so they were subjected to a third leaching treatment with 2M H2SO4 and H2O2 for another 4 hours. The temperature was kept constant at 75°C. The liquid / solid ratio was 10 L / kg in all examples.

[0097] The results of the ordinary metal removal tests are shown in Table 4. [Table 4] [Industrial Applicability]

[0098] While the disclosure of the present invention has been described with reference to particular illustrated embodiments, it will be understood that the disclosure encompasses numerous modifications thereof which will be apparent to those skilled in the art. Also, while the disclosure of the present invention has been described in relation to particular embodiments, it will be understood that further modifications are possible, and the present application is intended to cover all such modifications, uses, or adaptations and advances from the disclosure as described above within the scope of known or customary practice in the art and within the scope of the appended claims.

Claims

1. 1. A method for recycling metallic and non-metallic components from printed circuit boards (PCBs) having solder metal and at least one copper layer, comprising: a) shredding the PCBs; b) atomizing the shredded PCBs to produce a fine powder; c) removing plastic and epoxy resin from the fine powder; d) leaching, precipitating and recovering the Al, Fe, Zn, Ni, Cr, Au, Ag and Pd from the fine powder while producing a stripped member; e) leaching the peeled member containing Cu to prepare a filtrate in which Cu is precipitated; A recycling method comprising the steps of:

2. 2. The method of claim 1, wherein the PCBs are shredded to a particle size of 5-50 mm.

3. 3. The method of claim 1 or 2, further comprising: washing the fine powder with caustic soda or an extractant to remove epoxy resin from the shredded PCBs and expose the solder metal and at least one copper layer of the shredded PCBs; and treating the shredded and exposed PCBs in a solder leaching reactor to dissolve the solder metal and produce a solid phase and a leachate containing the recovered solder metal.

4. 4. The method of claim 3, wherein the caustic soda is a caustic soda consisting of 1-10M NaOH or the extractant is KOH or ammonium hydroxide.

5. 5. A method according to claim 3 or 4, characterized in that the solder metal is dissolved in a solution of sulfonic acid under the influence of an oxidizing agent in the solder leaching reactor.

6. 6. The method of claim 5, wherein the sulfonic acid is methanesulfonic acid (MSA).

7. 7. The method of claim 5 or 6, wherein the oxidizing agent is hydrogen peroxide, pure oxygen, enriched air, air, ozone, nitric acid, oxone, ammonium chlorite, ammonium chlorate, ammonium iodate, sodium hypochlorite, potassium hypochlorite, ammonium hypochlorite, sodium perchlorate, potassium perchlorate, or ammonium perchlorate.

8. 8. The method of any one of claims 3 to 7, wherein the recovered solder metal is Sn, Pb, Al, Ag, Cu, Fe, or a combination thereof.

9. 4. The method of claim 3, wherein the solid phase is atomized to a powder of less than 2 mm.

10. 10. The method according to any one of claims 1 to 9, further comprising the step of recovering ferromagnetic materials comprising Fe, Ni and Co by magnetic separation of the fine powder.

11. 11. The method according to any one of claims 1 to 10, characterized in that the fine powder is exfoliated using a hot extractor at a temperature of about 90-150°C.

12. 12. The method of claim 11, wherein the hot extractant is DMSO, DMF, or a combination of ethylene glycol and NMP extractant and catalyst.

13. 13. The method of claim 11 or 12, further comprising recovering the hot extraction agent from the liquid phase by vacuum stripping.

14. The peeling member is heated at a temperature of about 50 to 70° C. ２ SO ４ 14. The method according to claim 11, further comprising treating with

15. The method according to any one of claims 1 to 10, characterized in that the fine powder is thermally oxidized with an oxidizing agent in a heating reactor at a temperature of 400 to 950 ° C to remove plastic and epoxy resin and generate a gas phase.

16. The oxidizing agent is O ２ , air, or 21 to 100% O ２ The method according to claim 15, characterized in that the enriched air comprises

17. The gas phase produced is oxidized in a catalytic reactor or in an incinerator to convert all the organic components to CO ２ and H ２ 17. The method according to claim 15 or 16, further comprising converting the oxidized carbon dioxide (CO) to O and producing exhaust gas.

18. 4. The method of claim 3 further comprising the step of dissolving the epoxy resin cleaned from the shredded PCBs and regenerating the caustic soda or the extractant.

19. 20. The method of claim 18, wherein the shredded PCBs are treated at a temperature of about 50-120°C.

20. 20. The method of claim 18 or 19, wherein the shredded PCBs are treated in a reactor.

21. The Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, Pd and inert metals precipitated and recovered from the fine powder are treated with H ２ SO ４ to produce a liquid phase containing dissolved Al, Fe, Zn, Ni, Cr and trace amounts of other common metals, and a solid phase containing Cu, trace amounts of other common metals, Au, Ag, Pd and inert metals.

22. 22. The method of claim 21, wherein Al, Fe, Zn, Ni, Cr, and trace amounts of other common metals are precipitated from the liquid phase in a selective precipitation reactor.

23. A process as claimed in any one of the preceding claims, characterized in that the Cu and remaining ordinary metals are leached in a second leaching reactor.

24. H ２ SO ４ and a second oxidizing agent to leach Cu.

25. 25. The method of claim 24, wherein the second oxidant is hydrogen peroxide, pure oxygen, air, enriched air, ozone, nitric acid, oxone, ammonium chlorite, ammonium chlorate, ammonium iodate, sodium hypochlorite, potassium hypochlorite, ammonium hypochlorite, sodium perchlorate, potassium perchlorate, or ammonium perchlorate.

26. 26. The method according to any one of claims 21 and 23 to 25, characterized in that Cu is leached at 50 to 75°C.

27. The Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, Pd and inert metals precipitated and recovered from the fine powder are treated with H in a single reaction step. ２ SO ４ and an oxidizing agent to produce a liquid phase comprising dissolved Al, Fe, Zn, Ni, Cr, Cu, and a solid phase comprising Au, Ag, Pd and an inert metal.

28. 28. The method according to any one of the preceding claims, characterized in that Cu is deposited in a reactor with thorough mixing.

29. 28. The method of any one of claims 1 to 27, wherein Cu is precipitated by acetone, methanol, or a combination thereof.

30. 28. The method according to any one of the preceding claims, characterized in that Cu is recovered by diffusion penetration or electrowinning.

31. 31. The method according to any one of claims 1 to 30, further comprising the step of recovering residual metal after Cu has been deposited by electrodeposition.

32. 32. The method according to any one of claims 1 to 31, wherein the residual metals are Au, Ag and Pd.

33. 33. The method of claim 32, wherein the recovered residual metals are further extracted using sodium hypochlorite.

34. The recovered residual metals are then subjected to the CLEVR process. ＴＭ 33. The method of claim 32, wherein the extracted

35. A method according to any one of the preceding claims, characterized in that the PCBs are single layer, double layer or multi-layer.

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