DD288260A5 - METHOD FOR THE SELECTIVE DISASSEMBLY OF COMPOSITE MATERIALS - Google Patents

Abstract

The invention relates to a method for the selective decomposition of composite materials in electrical engineering / electronics. It is preferably applicable for the exposure of integrated metallic components, such as for PCB different Bestueckungsgrades, for cables u. a. m. Object of the invention are simplified Anlagenstammbaeume, reduced specific energy costs for the recovery of valuable materials from electronic waste or electronic waste and the creation of optimal conditions for further treatment and any necessary landfill accumulating Rueckstaende. The object is achieved according to the invention in that pre-shredded feed material is fed into a nip, drawn into it and subjected to combined pressure and shear forces, with a maximum of 1 m / s as guide value for the stress rate in the nip and approximately equal to the stress level large amounts of compressive, shear and tensile stress must be observed. {Procedure; Processing; electronic waste; Electronic waste; Composite materials; Wertstoffrueckgewinnung; decomposition; Conditions}

Description

be guaranteed.

2. The method according to claim 1, characterized in that the turntable is used as a grinding bowl and the surfaces of the rollers, grinding bowls and / or rotary body are used in a smooth or profiled form.

3. The method according to claim 1 and 2, characterized in that a difference of at least 0.5% of the maximum occurring speed is provided between the peripheral speeds of the rollers or between the peripheral speed of the rotary body and the corresponding rotational speed of the rolling track on the turntable.

4. The method according to claim 1 to 3, characterized in that the mechanical stress of the feed material is combined in the respective working gap with a pneumatic and / or gravity based discharge system as a transport and feeding technique for a downstream and the specific properties of the feed material accounting for sorting.

5. The method according to claim 1 to 4, characterized in that the feed material granular mineral material, preferably limestone, glass breakage and / or quartz sand, are admixed to a maximum proportion of 5 wt .-% of the total throughput.

Field of application of the invention

The invention relates to a method for the selective disassembly of composite materials of electrical engineering / electronics, in particular for the disassembly of printed circuit boards with different degree of assembly and cables. It is used in the processing of production waste and recycled material under the objective of cost-effective recovery of metallic ingredients.

Characteristic of the known state of the art

Several methods are known for recovering reusable product from waste or scrap of the electrical industry.

Resting screens

on the application of mechanical stresses, for example in the form of cutting, abrading or peeling the insulating layers of cables to expose the metallic components to be recovered and their subsequent separation,

- on the thermal decomposition in the form of cold brittleness before the targeted mechanical stress, in the form of the pyrolytic decomposition of the combustible fractions of composite materials or in the form of Veraschungsprozessen, in which, the metallic constituents are obtained from the Veraschungsrückständen and

- on the chemical dissolution of individual components of composites.

Thus, DE-OS 2328448 and 2449303 disclose the dissolution of the insulating materials of cable wastes by means of methyl-containing solvents. Pyrolytic processes have already been used for removing organic coatings of aluminum scrap on a moving grate according to DE-OS 3141423, for burning off impurities, on metal surfaces with reuse of the combustion gases according to DE-OS 3612892 and as a pre-treatment measure in the treatment of waste mixtures for decomposition lower-mineral and -rich fractions proposed according to DE-OS 3330577.

Pyrometallurgical methods and devices in the strict sense have already been proposed:

in DE-OS 3612 553 for the thermal pretreatment metal-containing waste products at temperatures up to 1000 ^c C with subsequent selective hydrometallurgischer separation of individual metal components, in DD 264716 for stage processing of batteries, printed circuit boards and electronic components by pyrolytic decomposition at 450 to 650 ° C and following Electrolysis of the pyrolysis slag, in DE-AS 2539105 for the co-combustion of

metal-containing waste and the associated melting of the metallic components, in DE-OS 2410320 for the

Abschwelen combustible layers on metals and in DE-OS 2108008 for the burning of plastic / metal Clearing with transfer of the metal into a reusable dust concentrate. For special applications, the DD 200528/1 for copper-clad PCBs will be used as inferior Copper scrap intended for remelting in a rotary kiln. The DD 258141 provides pre-shredded copper-containing Printed circuit board material at gas temperatures of 700 to 800 ⁰ C in admixture with additives to the exhaust system of a Give up furnace, perform an afterburning of the exhaust gases in a heat exchanger and wet-dusted

metallurgically treat solid copper-containing residues.

It is also known with DE-AS 2243194 the recovery of metals by smelting processed residues,

wherein pre-crushed metal and reducing agent or fuel in pelletized form the metallurgical furnace at

Working temperatures of at least 800 ° C are supplied. From various applications of known per se Kälteversprödung, for example, for cables and others Materials according to US 4251034 before impact or impact crushing, according to DD 265084 extended to predominantly

flat materials, are facing problems of economic refrigeration and the availability of cold-resistant materials for the

Equipment in corresponding treatment plants. Also known for pre-shredded materials is the use of hydrometallurgical processes in connection with Pre-enrichment stages, such as swim-sink divorce, for metal-coated plastic laminates in US 3335966

has been described. With the DE-AS 2635201 beyond the hydrometallurgical dissolution of metallic

Coating layers of base metals proposed with simultaneous separation of Isoliermaterialresten. The direct combination of integrating metal-dissolving leaching effects in suitable reagents and floating

the metal-free plastic component is known from DE-OS 2117434.

All the above-mentioned proposed solutions involve the following disadvantages:

The equipment and technological suspensions to be used for the application of the proposed devices and / or methods cause high operating costs and considerable investment sizes.

It is sometimes necessary to tolerate permanent chemical changes which adversely affect the subsequent metallurgical processing of the metals obtained, such as Cl "or ^ inclusions.

- The insulation material, such as cable insulation, is largely withdrawn for secondary use of materials.

- The known methods cause additional environmental pollution by the inevitable accumulation of liquid, dust or gaseous waste products.

It has also been proposed several times to subject the metal-containing residues to be treated to stresses with one target direction, to achieve a more or less complete exposure of the metals contained, and to avoid the disadvantages of other treatment methods.

Thus, it is known, for example, according to DE-OS 2556267 grind in a fixed gap cable insulation by means of rotating rollers or demolish or remove by intensive wear according to DE-OS 2608739 in the preheated medium, the softened insulating layers of cables.

In an industrial cable treatment plant, pre-shredded scrap cables are subjected to repeated pressure surges, for example in ball mills or hammer mills, according to DD-AP110136 until the insulation is torn by progressive wear and local plastic deformation and finally separated from the bonded metal. With this approach, specific energy consumption up to 260kWh / t is not uncommon in cable disassembly. In comparison with the crushing conditions, such as those for medium-hard rocks in modern grinding plants, resulting in specific energy consumption of a maximum of 20kWh / t, the unacceptability of the applied scrap cable preparation is clear. With DE-OS 3304391 has also been proposed to separate cable insulation by high pressure impinging water jets. Spezioll for cable scrap was inspired by DE-OS 2914184 to collect cables of finite length between rollers so that the insulation is claimed beyond the yield point and ruptures. For this purpose, various design solutions, such as profiled rolls with or without gradations according to US 3822615 and 4753001, roll inclination according to SU 1314409 and slotting or additional notching of the insulating layers with fixed or circumferential cutting tools according to SU 892 552 or DE-OS 2607943 proposed.

The well-known state of the art of electronic and / or printed circuit board scrap processing also includes reducing metal / plastic composite materials by multistage impact and / or cutting comminution to the extent that the particle size can be separated from the comminuted scrap by physical methods (DE-OS 3340165). This is also in accordance with the doctrine that impact and cutting machines are particularly well suited for elastic and tough materials (see ADOLPHI: "Grundzüge der Verfahrenstechnik", p.28).

According to the previously prevailing views, it must only be ensured by multi-stage comminution that the sufficiently large number of metal-free particles is present and, with limited mass output, a required recycling of material is ensured. The fine crushing of the thermoset base material, as it is mainly recorded in PCB scrap, due to the associated local particulate matter and heat development on the one hand and due to the existing landfill difficulties for the currently not economically usable finely divided thermosets on the other hand to such problems caused by working with several Feinzerkleinerungsstufen and with ever more intensive Aufmahlung not be degraded. It is to be estimated that the previously practiced fine comminution, for example of PCB scrap, to grain sizes of less than 0.2 mm, both because of the required crushing effort and because of the increasing risk of dust explosion considerable difficulties.

In the crushing machines used a complex particle stress takes place, without the simultaneous lifting of particles with their derived from the temperature dependence of the mechanical properties adverse consequences of the required repeal of the force and positive connection between base and coating material is achieved. Only from the preparation of hochfeiten elastic composite materials, such as tire scrap, it is known that material stresses were proposed and tested in which multiple successive pressure and shear stresses in highly elastic tire rubber cancel the form and adhesion between rubber and embedded fiber materials according to DO 251313.

In summary it can be estimated that the prior art for the treatment of composite waste electrical engineering / electronics with the aim of economic decomposition and the recovery of as many useful components a universally applicable method is not known. The main shortcomings of proposals made so far are the uncritical transfer of technical solutions of mineral processing to the secondary raw material use, the failure to dissipate energy-saving dissolution of the composite material before or during comminution, and unsustainable disposal concepts for the resulting in the composite material processing residues.

Object of the invention

The object of the invention is to provide a method for the selective decomposition of composites of electrical engineering and electronics, in particular printed circuit boards of different assembly levels and cables, with the simplified plant trunk trees, reduced energy costs for material recovery and technically manageable landfill solutions for accumulating residues can be achieved ,

Explanation of the essence of the invention

The invention is based on the technical object of providing a method for the selective disassembly of composite materials in electrical engineering / electronics, in particular printed circuit boards of different assembly levels and cables, in such a way that new process-specific combinations adapted to the specific feed material using known machine-technical solutions provide for both Cancellation of the positive and frictional connection between the different material components as well as an energetically advantageous comminution of the material to be used is achieved to the necessary extent. According to the invention the object is achieved in that roughly pre-shredded feed material formed between rotating rollers or between a rotating turntable and rolling bodies rotating thereon work gaps is abandoned. The feed material is so mechanically stressed during one or more pulls into the working gap as a result of simultaneously acting compressive, tensile and shear forces that at loading speeds of a maximum of 1.0 m / s in the working gap feed-dependent stresses in a height of about

/ Tg "umt /

be guaranteed.

This is achieved by the choice of the contact pressure of the rollers or rotary body, which is both Lagofixierung and elastic deformation of the feed material is to be secured. The setting is advantageously carried out so that the amount of compressive stress exerted on the feed material is equal to the amount of tensile stress, the shear stress in the material composite reversing shear stress T ₀ , " _{mt of} the elastically deformed feed material as a function of geometric conditions of the known comminution machine so is measured that it corresponds approximately to the normal stress acting in the nip. Essential to the invention is also that the turntable is used as a grinding bowl. It has proved to be advantageous to apply the surfaces of the grinding bowls, rollers and / or rotating bodies used in a smooth or profiled form. A special embodiment of the invention provides for a difference of at least 0.5% of the maximum occurring speed to be maintained between the circumferential speeds of the rollers or between the circumferential speed of the rotary bodies and the corresponding rotational speed of the rolling track on the turntable.

Furthermore, it is characteristic of the invention to combine the mechanical stress of the feed material in the respective working gap with a pneumatic and / or gravity-based discharge system, which is simultaneously effective as a transport and feeding technique for a nachgeachaltet and the specific properties of the feed material taking into account sorting. Ale sorting devices are preferably used per se known technical systems for separating the comminuted feed material according to the sorting characteristics grain size and / or grain bulk density.

It is also part of the essence of the invention that granular mineral material, preferably limestone, glass breakage and / or quartz sand, are admixed with the feed material up to a maximum proportion of 5% by mass of the total throughput. In addition to increasing the effectiveness of shear forces in the grinding material claimed by the comminution tools, the additives provided counteract as needed an agglomeration tendency, as can be observed for example in finely divided organic insulating materials.

embodiments

The invention will be explained in more detail below with two embodiments. This shows the

Table 1: Results of printed circuit board comminution tests with variation of the discharge and classifying conditions.

example 1

The embodiment 1 relates to the PCB in a comminution Versuchswälzmühle in which, _"IMT under stress conditions Tofuck = 6 MPa, T = 5MPaundn _Mah ibahn = 1m / s pre-crushed indeterminate circuit boards were enforced. It was achieved that at constant crushing conditions only the variation of the speed of the separator in the inner Mahlgutkreislauf between 0 (experiment 1) and 405 1 / min (experiment 3) with the intermediate 185 1 / min (experiment 2) at air flow rates of 400m ³ / h (experiment 1) and 240m ³ / h (experiments 2 and 3) was sufficient to reduce the proportion of fraction + 0.16mm from 3.3Ma% over 21.0Ma% to 56.7Ma% in the size reduction product. to rise.

The crushing result achieved in single-stage Wälzerkleinerung can be transferred in the same way to the metal separation, because even with simple air jet sighting without extreme expenses for the deposition of finest metal-free dusts from PCB base material high separation rates of the plate-like separated by the shear stress of the base copper coating are possible.

Example 2 The embodiment 2 relates to the processing of pre-shredded to about 15 ... 20mm single grain size copper and Aluminum cables with plastic and rubber cladding. Under similar load conditions as in Example 1, said cable pieces were abandoned and at Mahlbahngeschwindigkeiten by 0.5m / s claimed in a Wälzmühlo. The slip between the rotational speed of the

The driven grinding bowl and the peripheral speed of the rotating body pressed onto the grinding bowl in the corresponding rolling track was about 0.6% of the grinding bowl's rotating speed. When operating the grinding plant without

Sifter and conveying air was the claimed feedstock, consisting of crushed pieces of insulating material and light

deformed conductor material shares in the gravity discharge discharged from the grinding plant. As a result of the subsequent mechanical separation of the ground stock into individual fractions, it was noted that about 90% by weight of the metallic fractions were already digested after the one-time mill run, while the remainder required recycling.

When operating with carrier air about 40MmVh were about 90Ma .-% of the exposed non-metallic Component discharged into the exhaust system of the pilot plant, with a view of the discharged solid / air Mixture did not take place. The entire metal fraction and about 10% by weight of incompletely digested cable pieces entered the Gravity discharge. The specific electrical energy consumption for the tested process stages was about 30 kWh / t Feed material. Both in the Aufschliessversuchen with printed circuit boards as well as in the Kabelzerlegung was found that the use

granular and possibly in the processing process in the decomposition of the composites further minced mineral products, such as limestone, glass or quartz sand quartz, the Aufles improved results and above all undesirable agglomeration phenomena heated by the mechanical stress and partially softened insulation material.

It can be appreciated that it is possible by means of the simultaneous pressure and shear stress in the nip, the selective Disassembly of composite materials of electrical engineering / electronics to perform advantageous and thereby with about 15 to 20% of

To separate specific energy expenditures of known decomposition techniques and significantly reduced plant peripheries both handling-safe metal fractions and to produce relatively coarse-grained non-metallic products. For the determination of the grain size distribution in the metal-depleted crushed material, the main role is the intended one

Use of this accumulation material for subsequent processing or as cost effective and without damage to the Environment to be stored landfill.

Table 1: Results of PCB crushing tests in a test roller mill with variation of the discharge and Klassierbedingungen

d _K mm Transit totals - frequency in Ma.- ' air flow Trial 2 Vo Trial 1 85.6 Trial 3 +0.036 80.4 m ³ / h 82.3 80.9 +0.045 77.0 400 79.5 76.3 +0.050 75.6 240 66.6 71.7 +0.080 70.7 240 57.0 48.6 +0.090 67.9 21.0 32.2 +0.130 56.7 12.2 3.3 +0.200 51.7 2.5 1.7 +0.315 32.0 - - +0.500 14.6 - Test conditions: Speed of the attempt sifter 1 / min 0 Trial 1 185 Trial 2 '405 Trial 3

Claims (1)

1. A method for the selective decomposition of composite materials, preferably for the decomposition of composites of electrical engineering and electronics, such as printed circuit boards different Bestückungsgrades and cables, characterized in that roughly pre-shredded feed material abandoned between rotating rollers or between a rotating turntable and rotating therefrom rotational columns work columns and mechanically loaded during retraction into the working gap as a result of simultaneously acting compressive, tensile and shear forces such that at stress velocities of a maximum of 1.0 m / s in the working gap, load-dependent stresses at a height of approximately 'Tzug' ⁼ 'TDfuck' ⁼ '^ total'