Comparative Analysis About Degradation Mechanisms of Printed Circuit Boards (PCBs) in Slow and Fast Pyrolysis: The Influence of Heating Speed

Diaz, Fabian; Flerus, Benedikt; Nagraj, Samant; Bokelmann, Katrin; Stauber, Rudolf; Friedrich, Bernd

doi:10.1007/s40831-018-0163-7

Cited by 25 publications

(14 citation statements)

References 24 publications

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“…Combustion of hydrocarbons C x H y + (x + y/4)O 2 → xCO 2 + (y/2)H 2 O (4) C x H y + (x/2)O 2 → xCO + (y/2)H 2 ∆H = −74 kJ/mol (8) The basic heating principle of the traditional pyrolysis is based upon conduction, convection, and radiation, where material is heated completely. The principal features of the conventional pyrolysis are moderate heating rate (~0.17 • C/s), reaction temperature below 600 • C, and residence time between 10 s and 10 min [19,20]. In the traditional pyrolysis, the material is heated from outside to inside and the produced syngas has a relatively high retention time, which permits secondary reactions in the gas phase, which ultimately produces increased amount of condensates [10].…”

Section: Type Reactionsmentioning

confidence: 99%

Degradation Mechanism of Nickel-Cobalt-Aluminum (NCA) Cathode Material from Spent Lithium-Ion Batteries in Microwave-Assisted Pyrolysis

Diaz

Wang

Moorthy

et al. 2018

Metals

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Recycling of Li-Ion Batteries (LIBs) is still a topic of scientific interest. Commonly, spent LIBs are pretreated by mechanical and/or thermal processing. Valuable elements are then recycled via pyrometallurgy and/or hydrometallurgy. Among the thermal treatments, pyrolysis is the most commonly used pre-treatment process. This work compares the treatment of typical cathode nickel-cobalt-aluminum (NCA) material by conventional pyrolysis, and by a microwave assisted pyrolysis. In the conventional route, the heating is provided indirectly, while via microwave the heating is absorbed by the microwaves, according to the materials properties. The comparison is done with help of a detailed characterization of solid as well as the gaseous products during and after the thermal treatment. The results indicated at least three common stages in the degradation: Dehydration and evaporation of electrolyte solvents (EC) and two degradation periods of EC driven by combustion and reforming reactions. In addition, microwave assisted pyrolysis promotes catalytic steam and dry reforming reactions, leading to the strong formation of H2 and CO.

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Section: Type Reactionsmentioning

confidence: 99%

Degradation Mechanism of Nickel-Cobalt-Aluminum (NCA) Cathode Material from Spent Lithium-Ion Batteries in Microwave-Assisted Pyrolysis

Diaz

Wang

Moorthy

et al. 2018

Metals

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“…In this paper, the basic idea is to include the process of indium volatilization into a current recycling concept for WEEE with as little effort as possible. The main requirement for this, indeed, is the application of a pyrolysis step in the WEEE processing route which provides several other-probably more substantial-advantages [3,16]. Based on this fact, however, a simultaneous indium separation would be a great feature.…”

Section: Discussionmentioning

confidence: 99%

“…However, this polymer fraction probably contains BFR, which can influence the whole process and act as a halogenation agent in situ unless the polymers are not removed. In one of our preceding papers, we investigated the temperature dependence of the gaseous and solid pyrolysis products during the thermal decomposition of printed circuit boards (PCB) [16]. It was found that elevated temperatures and a high heating rate have a considerable influence on the decomposition mechanism of the organics and thus on the composition of the pyrolysis gas.…”

Section: Motivation and Innovative Approach Of This Workmentioning

confidence: 99%

Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Flerus

Swiontek

Bokelmann

et al. 2018

Metals

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The present study focuses on the pyrolysis of discarded smartphone displays in order to investigate if a halogenation and volatilization of indium is possible without a supplementary halogenation agent. After the conduction of several pyrolysis experiments it was found that the indium evaporation is highly temperature-dependent. At temperatures of 750 • C or higher the indium concentration in the pyrolysis residue was pushed below the detection limit of 20 ppm, which proved that a complete indium volatilization by using only the halides originating from the plastic fraction of the displays is possible. A continuous analysis of the pyrolysis gas via FTIR showed that the amounts of HBr, HCl and CO increase strongly at elevated temperatures. The subsequent thermodynamic consideration by means of FactSage confirmed the synergetic effect of CO on the halogenation of indium oxide. Furthermore, HBr is predicted to be a stronger halogenation agent compared to HCl.

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“…The last group of elements, i.e., the scarce elements, are mainly bound in the slag. However, depending on the chemical reactions inside the furnace, halides may also be formed and lost to the off gas [4]. Although the recycling process is quite well developed and plenty of research was done in that field, the distribution of scarce elements is still not fully understood, and an efficient recovery method is yet to be developed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Recyclability of a WEEE Slag by Means of Integrative X-Ray Computer Tomography and SEM-Based Image Analysis

et al. 2020

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Waste of electrical and electronic equipment (WEEE) is one of the fastest growing waste streams globally. Therefore, recycling of the valuable metals of this stream plays a vital role in establishing a circular economy. The smelting process of WEEE leads to significant amounts of valuable metals and rare earth elements (REEs) trapped in the slag phase. The effective manipulation of this phase transfer process necessitates detailed understanding and effective treatment to minimize these contents. Furthermore, an adequate process control to bring these metal contents into structures that make recycling economically applicable is required. Within the present study, a typical slag from a WEEE melting process is analyzed in detail. Therefore, the material is investigated with the help of X-ray computed tomography (XCT) and scanning electron microscopy (SEM)-based mineralogical analysis (MLA) to understand the typical structures and its implications for recycling. The influencing factors are discussed, and further processing opportunities are illustrated.

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Comparative Analysis About Degradation Mechanisms of Printed Circuit Boards (PCBs) in Slow and Fast Pyrolysis: The Influence of Heating Speed

Cited by 25 publications

References 24 publications

Degradation Mechanism of Nickel-Cobalt-Aluminum (NCA) Cathode Material from Spent Lithium-Ion Batteries in Microwave-Assisted Pyrolysis

Degradation Mechanism of Nickel-Cobalt-Aluminum (NCA) Cathode Material from Spent Lithium-Ion Batteries in Microwave-Assisted Pyrolysis

Thermochemical Modelling and Experimental Validation of In Situ Indium Volatilization by Released Halides during Pyrolysis of Smartphone Displays

Evaluation of Recyclability of a WEEE Slag by Means of Integrative X-Ray Computer Tomography and SEM-Based Image Analysis

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