WO2022123438A1 - Procédé respectueux de l'environnement pour le recyclage de déchets électroniques - Google Patents

Procédé respectueux de l'environnement pour le recyclage de déchets électroniques Download PDF

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Publication number
WO2022123438A1
WO2022123438A1 PCT/IB2021/061408 IB2021061408W WO2022123438A1 WO 2022123438 A1 WO2022123438 A1 WO 2022123438A1 IB 2021061408 W IB2021061408 W IB 2021061408W WO 2022123438 A1 WO2022123438 A1 WO 2022123438A1
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WO
WIPO (PCT)
Prior art keywords
process according
previous
waste
metallic
electronic waste
Prior art date
Application number
PCT/IB2021/061408
Other languages
English (en)
Inventor
António TORRES MARQUES
Margarida Maria DA SILVA MONTEIRO BASTOS
Liliana MARQUES MARTELO
Paulo Miguel SOARES DE SOUSA
Ana Cláudia RELVAS VIEIRA DIAS
Luís Manuel GUERREIRO ALVES ARROJA
Original Assignee
Universidade Do Porto
Universidade De Aveiro
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority claimed from EP20216239.2A external-priority patent/EP4008444A1/fr
Application filed by Universidade Do Porto, Universidade De Aveiro filed Critical Universidade Do Porto
Publication of WO2022123438A1 publication Critical patent/WO2022123438A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/80—Destroying solid waste or transforming solid waste into something useful or harmless involving an extraction step
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/04—Disintegrating plastics, e.g. by milling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/005—Preliminary treatment of scrap
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B11/00—Obtaining noble metals
    • C22B11/04—Obtaining noble metals by wet processes
    • C22B11/042—Recovery of noble metals from waste materials
    • C22B11/046—Recovery of noble metals from waste materials from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B2101/00—Type of solid waste
    • B09B2101/15—Electronic waste
    • B09B2101/17—Printed circuit boards [PCB]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B2017/001—Pretreating the materials before recovery
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B2017/001—Pretreating the materials before recovery
    • B29B2017/0021—Dividing in large parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0217—Mechanical separating techniques; devices therefor
    • B29B2017/0224—Screens, sieves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0262—Specific separating techniques using electrical caracteristics
    • B29B2017/0265—Electrostatic separation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0268—Separation of metals
    • B29B2017/0272—Magnetic separation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/02—Separating plastics from other materials
    • B29B2017/0213—Specific separating techniques
    • B29B2017/0286—Cleaning means used for separation
    • B29B2017/0289—Washing the materials in liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/04—Disintegrating plastics, e.g. by milling
    • B29B2017/0424—Specific disintegrating techniques; devices therefor
    • B29B2017/044—Knives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
    • B29B17/04—Disintegrating plastics, e.g. by milling
    • B29B2017/0424—Specific disintegrating techniques; devices therefor
    • B29B2017/0484—Grinding tools, roller mills or disc mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/34—Electrical apparatus, e.g. sparking plugs or parts thereof
    • B29L2031/3425—Printed circuits
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/02—Details related to mechanical or acoustic processing, e.g. drilling, punching, cutting, using ultrasound
    • H05K2203/0228—Cutting, sawing, milling or shearing
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
    • H05K2203/0779—Treatments involving liquids, e.g. plating, rinsing characterised by the specific liquids involved
    • H05K2203/0783—Using solvent, e.g. for cleaning; Regulating solvent content of pastes or coatings for adjusting the viscosity
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/17—Post-manufacturing processes
    • H05K2203/176—Removing, replacing or disconnecting component; Easily removable component
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/17—Post-manufacturing processes
    • H05K2203/178—Demolishing, e.g. recycling, reverse engineering, destroying for security purposes; Using biodegradable materials
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/225—Correcting or repairing of printed circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/52—Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention relates to the field of electronics, chemical engineering and environment, particularly to the field of electronic waste management and methods for recycling valuable metals.
  • the present invention relates to a method for recovering valuable metals contained in waste electronic material, particularly printed circuit boards, and more particularly, to a method for recovering gold fingers from waste printed circuit boards by separating several layers using an organic solution and then separating the gold fingers from the non-metallic and base metal components using a magnetic separation process.
  • Electronic scrap components contain potentially harmful materials such as lead, cadmium, beryllium, or brominated flame retardants (BFRs). Recycling and disposal of electronic waste may involve significant risk to health of workers and their communities.
  • BFRs brominated flame retardants
  • JP2001064735A discloses a method that recovers gold and other PMs from waste PCBs of waste mobile phones.
  • the invention in JP2001064735A relates to a method and a system for collecting gold and other PMs from a portable telephone set or the like.
  • the cut is referred to as "crushing", indicating that there is not a specific technique to cut the PCBs.
  • the separation of metals is obtained via a molten metals furnace, which operate at very high temperatures.
  • Document WO 2010/055489 relates to a method for treating materials containing a mixture of plastic and metal materials in electronic waste. This method includes crushing the material (20 to 30 mm) to be treated following a pyrolysis (between 300 and 600 °C) of the crushed material. After the pyrolysis process, a first magnetic separation is performed to separate the ferrous metal fraction (iron and iron derivatives) from the non-ferrous material (aluminum and zinc).
  • a second magnetic separation is performed to the non-ferrous fraction to separate the nonferrous metal fraction from the non-magnetic residue (copper, lead, tin, fiber glass and PMs, such as Au and Pt).
  • the non-magnetic residue copper, lead, tin, fiber glass and PMs, such as Au and Pt.
  • PMs such as Au and Pt.
  • This document suggests the recovery of the PMs, namely gold, contained in the non-magnetic fraction. It is described the use of sulphuric acid followed by electrowinning to recover copper. This document does not disclose any specific procedure or method to recover a valuable metal, namely gold, from the electronic waste.
  • Document US 7867317 discloses a method for recovering valuable metals contained in waste PCBs.
  • the method uses organic solvents for liberating metal and plastic laminated in waste PCBs and then separation and recovery of the liberated metal components using an electrostatic separation process.
  • the process includes:
  • the method of the present invention presents a different cut of the waste of PCBs focused on the connecting terminals containing the gold fingers from the PCBs that allows an increase in the amount of recovered gold. Additionally, the method of the present invention allows complete separation of gold fingers, copper laminates and plastic fraction through magnetic separation.
  • the method of the present invention leads to a complete delamination of the several constituent layers of PCBs or other electronic waste allowing to obtain copper layers separated from the gold fingers and the plastic fraction.
  • the magnetic separation performed in the method of the present invention allows to easily separate the metallic fraction of the electronic waste, namely gold fingers, which contains the PM, namely gold, from the copper foils and the plastic fraction.
  • the gold fingers can be magnetized by an external magnetic field and, thus, being easily separated from the other components (copper layers and fiber glass) of the mixture.
  • the method of the present invention performs a different cut of the waste of PCBs or other electronic waste.
  • the cut of the present invention is focused on the connecting terminals containing the gold fingers from the electronic waste, particularly PCBs, allowing an increase in the amount of gold recovered.
  • the present method is performed in a low-pressure reactor.
  • the increase of the pressure in the organic swelling process decreases the time of the complete delamination of the metal and plastic laminates in waste PCBs.
  • the complete separation of the copper laminates, the gold fingers and the plastic fraction occur preferably in 30-20 minutes, half the time reported in document US7867317 (1 h).
  • the optimum conditions of the present invention were obtained using different organic solvents, preferably N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) accompanied by a gold fingers recovery ratio of 98.3 and 97.1 % respectively, via this organic swelling pressure-assisted and magnetic separation process.
  • NMP N-methyl-2-pyrrolidone
  • DMSO dimethyl sulfoxide
  • the method of the present invention regards the separation process of the obtained wet or dried metal and plastic fractions after the organic swelling.
  • the gold fingers can be easily separated and recovered from the copper laminates and the plastic fraction through a magnetic separation since they possess magnetic properties.
  • a friendly method for the complete delamination of waste PCBs consists in dissolving the brominated epoxy resin (BER) in an appropriate organic solvent 3 ' 4,5 . This dissolution allows to destroy the reinforced multi-layered PCBs structure and, thus, the enveloped metals are liberated.
  • BER brominated epoxy resin
  • One of the main advantages of this method is that the BER does not decompose and does not produce toxic gases.
  • the most critical point corresponds to the subsequent efficient separation of the various metallic elements (gold fingers and copper laminates) from the non-metallic fraction (glass fiber), which is crucial if the desirable aim is to recycle selectively all valuable components, in particular gold.
  • the present invention discloses a new method for recovering valuable metals, particularly gold, from PCBs or other electronic wastes, by separating several polymeric layers using organic solvents and separating the non-metallic and other base metal components from gold fingers using magnetic separation with sieving.
  • the choice of the waste PCBs was targeted at random access memories (RAMs), graphics and soundboards, and ethernet boards of WEEE due to the high concentration of gold on their composition.
  • RAMs random access memories
  • WEEE ethernet boards
  • End-life PCBs may contain up to 60 different chemical elements and have a metal content as high as 40% by weight.
  • PCB is a thin board made of epoxy resin and glass fiber, which is coated with a layer of thin copper laminate.
  • the metals in PCB substrate are in the forms of copper laminates (10-27% of PCB mass) and the coatings [tin, nickel, gold, silver, etc.] on the surface of copper layers, pins and holes that increase conductivity and oxidation resistance.
  • the levels of PMs vary considerable depending on the age of the device.
  • the basic structure of the PCBs is the copper layer, glass fiber- reinforced epoxy resin and several metallic materials.
  • the present work relates to a new method for recovering valuable metals, particularly gold from PCBs, by separating several non- metallic layers using an organic solution and separating non-metallic components and copper laminates from gold fingers using magnetic separation with sieving.
  • the choice of the waste PCBs is targeted at random access memories (RAMs), graphics and sound boards, and ethernet boards from personal computers and laptops due to the high concentration of gold on their composition 6 .
  • RAMs random access memories
  • graphics and sound boards graphics and sound boards
  • ethernet boards from personal computers and laptops due to the high concentration of gold on their composition 6 .
  • the person skilled in the art will acknowledge the existence of other targets as for example processors for laptops, desktops, cell phones, servers, discs and the like.
  • the scope of the present invention is not limited to the components herein described.
  • the method for liberating and recovering gold from wastes is not limited to the components herein described.
  • PCBs includes, as shown in Figure 1: a) cutting the connecting terminals containing gold fingers from the PCBs using a mechanical process (for example a guillotine or a rotary knife), b) optionally placing the cut PCBs connected terminals in an overnight process with stirring in an appropriate organic solvent, c) performing an organic swelling in a low-pressure reactor with heating and stirring and finally, d) using magnetic separation process followed by sieving to recover the gold fingers from a mixture of the copper laminates and the NMF, optionally dried previously.
  • a mechanical process for example a guillotine or a rotary knife
  • the new method of the present invention allows separating the non-metallic and the two main metallic components (gold fingers and copper laminate) from the waste PCBs by separating the several laminated layers via simple use of organic solvents and obtaining a high gold recovery ratio, via this organic swelling pressure-assisted and magnetic separation process.
  • the method of the present invention has the advantages to provide a smart process that can minimize the generation of wastes, namely, dusts and wastewaters containing metals, energy consumption and equipment space. Furthermore, other important additional advantages of the present method, when compared with the main current technologies, is based on the simplicity, time and environmentally friendly character of the process developed to recover gold with high yield from the wastes PCBs.
  • the technical feature of cutting the connecting terminals containing valuable metals from electronic waste using a mechanical process for example a guillotine, a rotary knife or a grinder is of extreme relevance.
  • the specific cut ( Figures 2 and 3) of the connecting terminals containing valuable metals from the electronic waste allows the pre-concentration of the gold from the overall amount of electronic waste and benefits the separation and recovery in the subsequent steps.
  • a different cut of the electronic waste, such as PCBs waste, focused on the connecting terminals containing the gold fingers from the waste allows an increase in the amount of recovered gold or other valuable metal.
  • the optional technical feature consists in placing the cut PCBs or other electronic waste connected terminals in a pre-swelling process with stirring in an appropriate organic solvent.
  • the specific cut performed in the electronic waste is an important aspect of the present invention since it provides a high contact surface with the organic solvent during the subsequent swelling step in the low-pressure reactor, allowing the effective separation between the gold fingers or other valuable metal layers from the copper laminates and plastics fraction under mild conditions, preferably in less than one hour, more preferably in less than 45 minutes, even more preferably in less than 30 minutes, and most preferably in 20 minutes.
  • the technical feature of performing an organic swelling in a low-pressure reactor with stirring is of the utmost importance.
  • the swelling step using organic solvents for promoting the separation of the metallic and non-metallic parts of the electronic waste belongs to the state of the art, but the optimized conditions of the present invention, namely the duration of the swelling step and the dimensions of the cut pieces provide an unexpected result.
  • the method of the present invention is performed in a low- pressure reactor and it achieves complete separation in half the time of the usual processes known from the state of the art.
  • the technical feature of isolating gold fingers from a mixture of the copper foils and the fiber glass using a magnetic separation process with sieving is also very relevant.
  • the separation process proposed for gold fingers recovery from the non-metal and other base-metal components after organic swelling using magnetic separation with sieving is novel and inventive and provides an efficient, clean and easy way to separate the gold layers from the mixture containing copper and plastic layers.
  • low-pressure reactor it shall be understood as a sealed vessel (reactor) in which the process of the present invention is performed under enough pressure to promote the technical effect of complete delamination of the waste PCBs.
  • low-pressure reactor it shall be understood that a reactor performing the process of the present invention under a pressure from 1 to 10 atm is covered. Nevertheless, this parameter shall be interpreted in the broadest manner in the sense that the pressure depends on the volume of the sealed vessel (reactor), the volume of the solvent and temperature, the type of solvent itself and all these factors combined.
  • pre-swelling it shall be understood any type of swelling performed before the swelling step of the process of the present invention.
  • organic solvent any carbon-based substance capable of dissolving or dispersing one or more other substances.
  • organic solvent it shall also be understood the mixture of two or more organic solvents as well as the mixture of different functional groups in the same molecule of organic solvent.
  • polymeric components it should be understood any plastic, resin and fiber glass components.
  • non-metallic fraction it should be understood any non-metallic components, such as fiber glass and polymeric components.
  • Figure 1 is a flow diagram of the overall procedure for recovering gold fingers (plus copper layers and other non-metallic fraction) from the waste PCBs according to the present invention.
  • Figure 2 Connector's terminals containing gold fingers before treatment (A); approximate length (B) and width (C) of connector's terminals containing gold fingers before treatment.
  • Figure 3 Schematic drawing of a cut and its average length (15 mm), average width (0.2-7.0 mm) and its average height (4 mm).
  • Figure 4 Separated components obtained after the swelling of the waste PCBs constituted by glass fibers, gold fingers and copper laminates using NMP as solvent.
  • the experimental conditions were solid/liquid ratio of 1:10, waste PCB area/size of 60 mm 2 /15x4 mm, at 150 °C for 30 min with pressure, without overnight and velocity of 1000 rpm.
  • the cut pieces are putted into an appropriate organic solvent listed below and then optionally stirred (pre-swelling process), which will help the liberation of the metallic and non-metallic components from the waste PCBs in the subsequent swelling process.
  • a cutting tool such as a grinder, a knife rotary or a guillotine
  • the cut waste of PCBs is preferably put into the organic solvent (in a solid/liquid ratio of 1:10 g/mL or preferentially 1:5 g/mL) for an optional period of 17 hours with a stirring of 600 rpm.
  • the mixture resultant from the optional pre-swelling (pre-swollen cut waste of PCBs together with the organic solvent) or the cut waste of PCBs (in a solid/liquid ratio of 1:10 g/mL or preferentially 1:5 g/mL) is preferably put into a low-pressure reactor using stirring to efficiently cause the dissolution of the BER using one or a mixture of organic solvents.
  • the solvents can be chosen among others: amides [such as dimethylformamide (DMF), dimethylacetamide (DMA), hexamethylphosphoramide (HMPA)], ketones [such as, methylethylketone (MEK), cyclohexanone, cyclopentanone, acetone], lactones [such as y-butyrolactone, y-caprolactone, y-valerolactone, s- caprolactone], sulfoxides [such as, dimethyl sulfoxide (DMSO), diethyl sulfoxide], lactamas [such as N-methylpyrrolidone (NMP), N-ethylpyrrolidone, N- propylpyrrolidone, N-buthylpyrrolidone], carboxylic acids [such as acetic acid], sulfonic acids [such as methanesulfonic acid], alcohols [such as, tetra hydrofurfuryl alcohol (TFA
  • the stirring is preferentially but not restricted performed at a rotation rate ranging from 600 to 1000 rpm at a temperature range between 60 °C to 250 °C, depending on the boiling point (Bp) of the solvent, with pressure during a sufficient period of time, in the specific case of the results presented, 30 minutes were used to efficiently cause the optimum dissolution of the BER using the organic solvent and, consequently, the liberation of the non-metallic and metallic layers.
  • the metallic and non- metallic fractions After swelling is performed, it is preferable to recover the metallic and non- metallic fractions, along with collecting the organic solvent via solid-liquid separation step. After the solid-liquid separation, the solid fraction containing the metallic and non- metallic components recovered are subject to an optional drying step, and then the gold laminates are separated from the copper foils and the non-metallic fraction using magnetic separation process with sieving. The separation process is carried out using magnetic separation.
  • the sieving process allows separating the large fibers using sieves preferably from 0.707 to 2mm, remaining the recovered gold fingers separated.
  • the copper and other base metals are separated from the non-metallic fraction recovered using an established process, such as electrostatic separation.
  • the used organic solvent is recycled by evaporation.
  • Table 1 summarizes the gold fingers recovery yield results achieved according to the present method, after organic swelling with each described solvent followed by magnetic separation.
  • the connecting terminals from the waste PCBs are cut in a size area of 60 mm 2 (15x4 mm) using a guillotine, 3g of the cut waste of PCBs is put into 30 mL of NMP (solid/liquid ratio 1:10 g/mL) into a low-pressure reactor made of stainless steel using two magnetic helical stirrers. The temperature is kept at 180 2 C and the resultant pressure achieved was about 3 atm. The stirring is performed for 30 minutes at a revolution velocity of 600 rpm. After the stirring finished, the swollen residue is separated from the organic solution via the filtering process and then dried. Subsequently, the dried residue is put into a flask under a stir plate for the separation process.
  • NMP solid/liquid ratio 1:10 g/mL
  • the separation process is carried out using a magnetic stirrer at a revolution velocity of 600 rpm for 30 minutes.
  • the gold fingers attracted to the magnet are then recovered. Additionally, to increase the recovery rate of the gold fingers, they are passed in a sieve with 2 mm and successively to another one of 0.707 mm. At the end of this method, the gold fingers are recovered with a rate of 98.3 % plus a mixture of fiber glass and copper layers.
  • the connecting terminals from the waste PCBs are cut in a size area of 60 mm 2 (15x4 mm) using a guillotine, 3g of the cut waste of PCBs is put into a goblet containing 30 mL of DMSO (solid/liquid ratio 1:10 g/mL) and, then, stirred at a rotation of 600 rpm for 17 hours (pre-swelling). After the pre-swelling, the content of the goblet is transferred into a low-pressure reactor made of stainless steel using two magnetic helical stirrers. The temperature is remained at 180 °C and the resultant pressure achieved was about 3 atm. The stirring is performed for 30 minutes at a revolution velocity of 900 rpm.
  • the swollen residue is separated from the organic solution via a solid-liquid separation and the solid is dried at a temperature of 80 °C in a vacuum oven. Subsequently, the dried residue is put into a flask under a stir plate for the separation process. The separation process is carried out using a magnetic stirrer at a revolution velocity of 600 rpm for 30 minutes. The gold fingers are attracted to the magnet and, thus, recovered from the remaining mixture. Additionally, to increase the recovery rate of the gold fingers, the dried residue is passed to a sieve with 2 mm and successively to another one of 0.707 mm. At the end of this method, the gold fingers are recovered with a rate of 97.1% plus a mixture of fiber glass and copper layers.
  • the present disclosure describes a new process to recycle valuable metals, particularly gold fingers from waste electronic material, particularly PCBs.
  • a swelling step of the cut connecting terminals containing gold from the waste PCBs, performed in a closed reactor, followed by the magnetic separation with sieving of the swollen mixture provides a rapid, efficient clean and easy way to separate the gold fingers from the other components (without dust formation).
  • copper laminates can be recovered from the non- metallic fraction by applying an electrostatic separation process of the remaining mixture.

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Abstract

La présente invention divulgue un procédé de récupération de métaux précieux à partir de déchets électroniques comprenant les étapes consistant à couper les terminaux des déchets électroniques impliquant des fractions métalliques et non métalliques à l'aide d'un procédé mécanique, la coupe étant effectuée sur les terminaux de connexion des déchets électroniques ; à placer éventuellement les terminaux de connexion de déchets électroniques coupés dans un solvant organique approprié en vue d'un pré-gonflement sous agitation pendant une nuit ; à effectuer un gonflement en milieu organique dans un réacteur à basse pression avec chauffage et de préférence sous agitation ; puis à séparer les parties en or des composants en plastique et en métal de base à l'aide d'un procédé de séparation magnétique suivi d'un tamisage.
PCT/IB2021/061408 2020-12-07 2021-12-07 Procédé respectueux de l'environnement pour le recyclage de déchets électroniques WO2022123438A1 (fr)

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US20240260199A1 (en) * 2023-01-31 2024-08-01 Vestas Wind Systems A/S Recycling printed circuit boards using swelling agent
WO2024160324A1 (fr) * 2023-01-31 2024-08-08 Vestas Wind Systems A/S Procédé de recyclage d'une structure composite dotée d'un élément contenant un métal

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