• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Method for recycling printed electronic circuit boards comprising the following steps: obtaining fragments of a printed electronic circuit board with a size less than 10 mm: mixing the fragments of the printed circuit boards with a liquid with a density between 1 and 2.8 g/cm3, stir the mixture obtained in the previous stage by applying ultrasound: and separate the different fractions produced in the previous stage. As well as a method of recovering metals of this type of plates comprising the recycling method mentioned above. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2739880A1
    申请号:ES201930822
    申请日:2019-09-24
    公开日:2020-02-04
    发明作者:Lazaro Ana Maria Mendez；Sanchez Ignacio Sanchez；Alonso Jose Manuel Fidalgo
    申请人:Universidad Politecnica de Madrid；
    IPC主号:
    专利说明:

    [0001]
    [0002]
    [0003]
    [0004] Field of the Invention
    [0005]
    [0006] The present invention is encompassed in the area of urban mining and circular economy, and its main objective is to reduce the content of plastics and fibers in electronic waste, namely printed electronic circuit boards, facilitating the subsequent recovery of the metals present in these residues by mineral, pyrometallurgical and hydrometallurgical methods.
    [0007]
    [0008] Background of the invention
    [0009]
    [0010] Printed electronic circuit boards are an important secondary source of metals of great economic value (Cu, Ag and Au, among others). However, the recovery of metals from these wastes by conventional methods, in particular mineral, pyrometallurgical or hydrometallurgical methods, presents important environmental and technological problems due to the presence of epoxy resins with flame retardants, as well as fiberglass.
    [0011]
    [0012] In particular, the presence of a high content of epoxy resins, in many cases greater than 40% by weight, causes that when these electronic wastes are subjected to high temperatures, polluting gases are emitted. On the other hand, the presence of flame retardant agents, generally compounds comprising bromine, causes the combustion of these compounds only to occur at very high temperatures. This limits the amounts of treatable printed circuits in facilities in pyrometallurgical companies. On the other hand, the presence of epoxy resins can also hinder the recovery of metals by hydrometallurgical techniques.
    [0013]
    [0014] For the recovery of metals found in printed electronic circuits, technologies from the metallurgical industry, mainly pyrometallurgical techniques, and to a lesser extent hydrometallurgical techniques are applied. However, in the techniques proposed in both fields there is no treatment that effectively separates the metal fraction from the rest of the materials, which makes it difficult to recover the metals.
    [0015] More specifically, we can say that there are currently different manufacturers of printed electronic circuit recycling lines on the market. These companies combine machines in the field of mineralurgy to reduce the size, separate metal fractions by using electromagnets and magnetic separators, and classify other components using vibration and sieving techniques. However, with these methods it is not possible to make a separation of all the elements that make up the printed electronic circuit boards, since small elements of some fractions with others are always attached.
    [0016]
    [0017] Spanish patent ES2030417 T3 describes a recycling process for high-power batteries of any construction, size and chemical composition, as well as electronic components and assembled printed circuit boards and electronic components. In this patent the components subject to recycling are pyrolyzed without a pre-treatment classification. Pyrolysis is intended to eliminate the initial materials of substances that cannot be further treated in the following additional processing. Due to this treatment, a set of gases is produced which is treated by washing. The subsequent recovery of metals is done by electrolysis.
    [0018]
    [0019] On the other hand, patent application CN101270411 proposes a method for separating the polymers by wetting and impregnating with an organic compound, in particular alcohols of different molecular size; while patent application US20050246879 proposes a method of pressing and heating until the plate is softened.
    [0020]
    [0021] Patent application CN107058747 describes a method for treating printed circuit boards with a combination of blown copper smelting enriched with oxygen. This patent describes a pretreatment of printed circuits. First, the circuits are heated to eliminate the tin that is present in them. Subsequently, a reduction in size is performed by crushing the circuits. In the next stage the smelting of the crushed elements is carried out and it is processed in ovens. One of the problems that this process presents is the generation of gases from the components that act as retarders and that are found in the printed circuits. In addition to this, since the metal fraction is not separated from the rest of the components, it is more expensive to obtain these metals in the smelting furnaces.
    [0022] The utility model CN206372924 describes a unit that allows the pretreatment of printed circuits and the separation of the materials that make them up. This treatment system incorporates blades that allow to reduce the size of the printed circuits, a magnetic separator to perform a first separation of ferrous elements, and a system of vibration and centrifugation that allows the classification of the rest of materials and their subsequent sieving . Through this process a separation of the different materials found in the printed circuits is achieved, but the release of the metal fraction, which still contains adhered plastic elements, is not achieved.
    [0023]
    [0024] Unlike the methods known to date, the method for recycling printed circuit boards of the present invention minimizes the use of organic compounds, as well as the use of high temperatures that can generate volatile, while simplifying and facilitating the subsequent recovery of metals.
    [0025]
    [0026] In the method described here, the release of the different materials found in the printed circuits (metals, fiberglass and polymers) is favored, so that the method can be used as a previous step to the mineral processes achieving a greater separation of metal fractions. This allows a better subsequent treatment by classical pyrometallurgical or hydrometallurgical methods and a greater recovery of all the elements.
    [0027]
    [0028] Description of the invention
    [0029]
    [0030] The method of the present invention makes it possible to enrich the metal fraction content by separating a large number of polymers and glass fibers from the rest of the materials, minimizing or eliminating the technical and environmental problem to which the recovery processes of the materials are currently subjected. metals present in the printed electronic circuits, and facilitating the subsequent recovery of these metals by mineral, pyrometallurgical and hydrometallurgical methods.
    [0031]
    [0032] Thus, as a result of the method described in this document, a metal concentrate with a much lower polymer and fiber content than in untreated printed electronic circuit boards is obtained. Additionally, this method allows the reuse of polymers and glass fibers separated from the metal fraction.
    [0033] The present method has as main novelty the use of ultrasonic technology applied to the process of separation of metals and organic supports. Especially advantageously, this method allows the plastic content of these electronic waste to be reduced by more than 40%.
    [0034]
    [0035] In particular, the present invention provides a method of recycling printed electronic circuit boards comprising the following steps:
    [0036] a) obtain fragments of at least one printed electronic circuit board with a size less than 10 mm, preferably less than 2 mm;
    [0037] b) mixing the fragments with an aqueous solution, preferably with a density between 1 and 2.8 g / cm3;
    [0038] c) stir the mixture obtained in the previous stage by applying ultrasound, preferably for a period exceeding 2 minutes, resulting in a densimetric separation of the main components of the printed electronic circuit board, i.e. metals, glass fibers and polymers;
    [0039] d) separation of the different fractions produced in step c).
    [0040]
    [0041] Fragments of the electronic circuit board printed in step a) of the method described herein can be obtained by fragmentation, in particular by crushing, grinding or a combination of the foregoing.
    [0042]
    [0043] Through the application of ultrasound, polymers, fibers and metals that may be included in the printed electronic circuit board fragments are separated, resulting in different fractions due to the different density of these materials. In step d) of the recycling method described herein, the different density of the materials, in particular polymers, glass fibers and metals, is used to separate them.
    [0044]
    [0045] Optionally, the method for recycling printed electronic circuit boards described herein may comprise an additional stage, where the mixing of step c) is subjected to a centrifugation process to increase the separation efficiency of the different fractions before of the physical separation of these fractions in stage d).
    [0046]
    [0047] In preferred embodiments of the present invention, the method may comprise the addition of a chemical additive that generates a gas inside the aqueous solution. In particular, an oxidizing compound to favor the separation of the fractions (metals, fibers and polymers). This oxidizing compound can be, for example, oxygen or hydrogen peroxide.
    [0048]
    [0049] In particular embodiments of the present invention, the method for recycling electronic circuit boards described herein may preferably take place by applying ultrasound with a power of 320 W, at a temperature between 20 ° C and 50 ° C, more preferably between 30 ° C and 40 ° C, for a period of time greater than 2 min, preferably equal to or greater than 10 min. In particular, it is preferred that the application of ultrasound takes place intermittently at various intervals of 2 min to 10 min duration each.
    [0050]
    [0051] The advantages of this recycling method are the following:
    [0052]
    [0053] - The possibility of using an aqueous solution that can be recirculated without the need to incorporate chemical compounds that are harmful to the environment. Consequently, no environmental pollutants are generated other than those present on the printed circuit boards themselves.
    [0054]
    [0055] - The use of ultrasound as a source of separation energy. It is a type of energy considered clean, which by means of creating cavities and shock waves within the liquid, localized and very high temperatures and pressures are reached, thus allowing the disintegration of the sample particles and the separation of their components.
    [0056]
    [0057] - The fractions produced do not suffer significant chemical changes, so the recycling method described here allows the recovery and / or reuse of the different fractions obtained from printed electronic circuit boards, in particular the metal-enriched fraction which is deposited at the bottom of the container where densimetric separation takes place by ultrasonic application.
    [0058]
    [0059] This procedure, in the sector of urban mining and urban economy, represents an important advance in the management of electronic waste since, on the one hand, it allows the recovery of the metals present in this type of waste and, on the other hand, it allows Recover plastics and fiberglass using environmentally friendly methods.
    [0060] The present invention also relates to the different fractions obtained by the method of the present invention.
    [0061]
    [0062] Likewise, the present invention also relates to a method for the recovery of metals from printed electronic circuit boards comprising:
    [0063] - i) obtain a fraction enriched in metals by means of the recycling method described in this document, and
    [0064] - ii) subjecting the metal-enriched fraction to a mineral, pyrometallurgical or hydrometallurgical process, this step being possible by any conventional procedure for the person skilled in the art.
    [0065]
    [0066] Brief description of the figures
    [0067]
    [0068] Figures 1, 2 and 3: These figures show different images obtained with an optical microscope of the fraction deposited in the background after the treatment of the printed electronic circuit board fragments according to Example 1
    [0069]
    [0070] Figures 4 and 5: These figures show different images obtained with an optical microscope of the supernatant fraction after the treatment of the printed electronic circuit board fragments according to Example 1.
    [0071]
    [0072] Examples
    [0073]
    [0074] EXAMPLE 1: A sample (0.5 grams) of fragments of printed electronic circuit boards with a size less than 2 mm was prepared.
    [0075]
    [0076] The test conditions were as described below:
    [0077] • Temperature: 35 ° C
    [0078] • Aqueous solution: 10 mL of H2O is added to the sample
    [0079] • Ultrasonic bath: it worked with a power of 320 W
    [0080] • Rehearsal time: 20 minutes (10 minutes + 10 minutes)
    [0081]
    [0082] The sample was placed in 1 glass bottle of 15 mL capacity and sealed. Then, when the temperature reached 35 ° C, the sample was introduced into the ultrasonic bath. After the first 10 minutes, it was observed how some metallic elements began to deposit in the background, while in the surface began to form a layer of glass fibers, polymers and small metal particles.
    [0083]
    [0084] The sample was reintroduced into the ultrasonic bath for another 10 minutes. At the end of time, it was observed that a separation between the plastic elements (forming a very differentiated layer at the top) and the metal elements (they were deposited at the bottom) had continued to occur.
    [0085] After significant changes were observed in the sample of fragments smaller than 2 mm, the physical separation of the different fractions of the sample was made: one from the floated part, another from the intermediate part and another from the bottom part. It was found that at the bottom the metal fraction had been deposited with almost no fiberglass presence (Figures 1,2 and 3), in the intermediate part most of the fiberglass fraction had been deposited with the presence of some elements metallic, and in the supernatant part (Figures 4 and 5) the presence of both fiberglass, polymers and small metal particles stood out. The following table shows the weights and the percentage that represents the total recovered in each fraction.
    [0086]
    [0087] SHOWS %
    [0088] FUND 39.4
    [0089] HALF 48.4
    [0090] FLOAT 12.2
    [0091]
    [0092] EXAMPLE 2: Three samples corresponding to fragments with a size larger than 2mm of mobile printed circuit boards were prepared, each of the samples of approximately 1 gram. The conditions under which the test was performed were the following:
    [0093]
    [0094] • Temperature: 35 ° C
    [0095] • Aqueous solution:
    [0096] or M1 and M2: 20 mL of H2O was introduced into two of the samples,
    [0097] or M3: 6 mL of H2O2 (30%) was introduced into another sample, and it was completed with 14 mL of H2O up to 20 mL of solvent
    [0098] • Ultrasonic bath: it works at a power of 320 W
    [0099] • Rehearsal time: 20 minutes
    [0100] • Centrifugation: 5 minutes at 1000 rpm
    [0101] The sample was introduced with the addition of an oxidizing agent (M3) and a sample with distilled water (M1) in 2 hermetically sealed glass jars and subsequently introduced into the ultrasonic bath. To compare, a third sample (M2) was kept out of the ultrasonic bath. After 20 minutes, it was observed that in the sample with H2O2 (M3) there was a better separation of the components of the printed circuit boards and, additionally, a greater amount of metals was observed at the bottom of the container.
    [0102]
    [0103] Then, the 3 samples (M1, M2 and M3) were centrifuged at 1000 rpm for 5 minutes.
    [0104]
    [0105] Once this part of the test was completed, the fraction deposited at the bottom of the floating fraction was separated and the samples were analyzed under an optical microscope. It was observed that the sample to which the oxidizing agent had been added showed a greater separation between the metal fraction and the fiber and polymer fractions.
    权利要求:
    Claims (7)
    [1]
    1. - A method for recycling printed electronic circuit boards comprising the following stages:
    a) obtain fragments of at least one printed electronic circuit board less than 10 mm in size;
    b) mix the fragments with an aqueous solution;
    c) stir the mixture obtained in the previous stage by applying ultrasound; d) separation of the different fractions produced in step c).
    [2]
    2. - The method according to claim 1, wherein the fragments obtained in step a) are smaller than 2 mm.
    [3]
    3. - The method according to any one of claims 1 to 2, wherein step a) comprises obtaining the fragments of the electronic circuit board printed by fragmentation.
    [4]
    4. - The method according to any one of claims 1 to 3, wherein the fragments are mixed with an aqueous solution with densities between 1 and 2.8 g / cm3.
    [5]
    5. - The method according to any one of claims 1 to 4, wherein step b) comprises the addition of a chemical additive that generates a gas inside the aqueous solution.
    [6]
    6. - The method according to claim 5, wherein the chemical additive is an oxidizing agent selected from the group consisting of oxygen and hydrogen peroxide.
    [7]
    7. - A method of recovering metals from printed circuit boards comprising:
    - i) obtaining a fraction enriched in metals by means of the recycling method as described in any one of claims 1 to 6, and
    - ii) subject the metal-enriched fraction to a mineral, pyrometallurgical or hydrometallurgical procedure.
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    同族专利:
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    ES2739880B2|2021-06-11|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP2003155523A|2001-11-19|2003-05-30|Sumitomo Bakelite Co Ltd|Method of recovering metal from multilayer substrate chip, and apparatus therefor|
    CN104745824A|2015-03-17|2015-07-01|昆明理工大学|Method for recovering copper from waste circuit board|
    CN105396865A|2015-12-09|2016-03-16|上海大学|Method for removing components of waste circuit board by virtue of ultrasonically-assisted acidic compound solvent|
    CN109609767A|2018-12-26|2019-04-12|北京工业大学|A kind of waste printed circuit board noble metal based on ultrasonic wave added efficiently separates recovery method|
    法律状态:
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    优先权:
    申请号 | 申请日 | 专利标题
    ES201930822A|ES2739880B2|2019-09-24|2019-09-24|METHOD FOR RECYCLING PRINTED CIRCUIT BOARDS|ES201930822A| ES2739880B2|2019-09-24|2019-09-24|METHOD FOR RECYCLING PRINTED CIRCUIT BOARDS|
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