Improving bromine fixation in co-pyrolysis of non-metallic fractions of waste printed circuit boards with Bayer red mud

Chen, Ye; Zhang, Yi; Yang, Jiakuan; Liang, Sha; Liu, Kang; Xiao, Keke; Deng, Huali; Hu, Jingping; Xiao, Bo

doi:10.1016/j.scitotenv.2018.05.269

Cited by 62 publications

(11 citation statements)

References 37 publications

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“…During this process, the metallic and nonmetallic fractions of WPCBs (NMF-WPCBs) are separated with coupled mechanical processes, such as electrostatic separation, pneumatic separation and eddy-current separation. NMF-WPCBs account for 60–70 wt.% of the WPCBs and contain hybrid components, posing a major challenge to the environment (Chen et al, 2018b). Recently, explorative research has been conducted using NMF-WPCBs to prepare polymer composites (Hu et al, 2018; Kovačević et al, 2017), building materials (Kurup and Senthil Kumar, 2017; Xin et al, 2017) and absorbents (Hadi et al, 2015; Xu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs)

Yao

Xiong

et al. 2020

Waste Manag Res

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In this study, the pyrolysis behaviour of nonmetal fraction of waste printed circuit boards (NMF-WPCBs) was studied based on five model-free methods and distributed activation energy model (DAEM). The possible decomposition mechanism was further probed using the Criado method. Thermogravimetric analysis indicated that the NMF-WPCBs pyrolysis process could be divided into three stages with temperatures of 37–330°C, 330–380°C and 380–1000°C. The mass loss at different heating rate was determined as 26.85–29.98%, 13.47–24.21% and 20.43–23.36% for these stages, respectively. The activation energy ( Eα) from various model-free methods first increased with degree of conversion ( α) increasing from 0.05 to 0.275, and then decreased beyond this range. The coefficient ( R) from the Flynn–Wall–Ozawa (FWO) method was higher, and the resulting Eα fell into the range of 214.947–565.660 kJ mol−1. For the DAEM method, the average Eα value was determined as 337.044 kJ mol−1, comparable with 329.664 kJ mol−1 from the FWO method. The thermal decomposition kinetics of NMF-WPCBs could be better described by the second-order reaction.

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Section: Introductionmentioning

confidence: 99%

Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs)

Yao

Xiong

et al. 2020

Waste Manag Res

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“…Copyrolysis of metals and their oxides with WPCBs has attracted a lot of interest. The metal can be used as a catalyst for reducing the activation energy of the reaction and reducing pyrolysis energy consumption; on the other hand, it can be used to fix bromine by forming metal bromides. − The metals include the WPCB’s own metal, added metal oxide, and industrial solid waste. − The Cu and Fe metals and metal oxides (CuO, Fe 2 O 3 , PbO, ZnO) have good catalytic effects, so they can improve the quality of pyrolysis products and debromination efficiency. , Gao et al showed that in the presence of copper, the reaction activation energy (Ea) decreased from 175.62 kJ/mol to 164.45 kJ/mol, promoting the cleavage of C–Br bonds and the generation of free radicals (Br*) and the decomposition of the brominated epoxy resin …”

Section: Pyrolysis Debromination With Additivesmentioning

confidence: 99%

Debromination with Bromine Recovery from Pyrolysis of Waste Printed Circuit Boards Offers Economic and Environmental Benefits

Liu

Zhan

2023

Environ. Sci. Technol.

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Bromine is an important resource that is widely used in medical, automotive, and electronic industries. Waste electronic products containing brominated flame retardants can cause serious secondary pollution, which is why catalytic cracking, adsorption, fixation, separation, and purification have gained significant attention. However, the bromine resources have not been effectively reutilized. The application of advanced pyrolysis technology could help solve this problem via converting bromine pollution into bromine resources. Coupled debromination and bromide reutilization during pyrolysis is an important field of research in the future. This prospective paper presents new insights in terms of the reorganization of different elements and adjustment of bromine phase transition. Furthermore, we proposed some research directions for efficient and environmentally friendly debromination and reutilization of bromine: 1) precise synergistic pyrolysis should be further explored for efficient debromination, such as using persistent free radicals in biomass, polymer hydrogen supply, and metal catalysis, 2) rematching of Br elements and nonmetal elements (C/H/O) will be a promising direction for synthesizing functionalized adsorption materials, 3) oriented control of the bromide migration path should be further studied to obtain different forms of bromine resources, and 4) advanced pyrolysis equipment should be well developed.

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“…Pyrolysis is typically employed due to its energy conversion efficiencies and less severe environmental impacts as compared to combustion/incineration [64][65][66][67].…”

Section: Pyrolysismentioning

confidence: 99%

Assessment of Pre-Treatment Techniques for Coarse Printed Circuit Boards (PCBs) Recycling

et al. 2021

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Waste electrical and electronic equipment or e-waste generation has been skyrocketing over the last decades. This poses waste management and value recovery challenges, especially in developing countries. Printed circuit boards (PCBs) are mainly employed in value recovery operations. Despite the high energy costs of generating crushed and milled particles of the order of several microns, those are employed in conventional hydrometallurgical techniques. Coarse PCB pieces (of order a few centimetres) based value recovery operations are not reported at the industrial scale as the complexities of the internal structure of PCBs limit efficient metal and non-metal separation. Since coarse PCB particles’ pre-treatment is of paramount importance to enhance metal and non-metal separations, thermal, mechanical, chemical and electrical pre-treatment techniques were extensively studied. It is quite evident that a single pre-treatment technique does not result in complete metal liberation and therefore several pre-treatment flowsheets were formulated for coarse PCB particles. Thermal, mechanical and chemical pre-treatments integrated flowsheets were derived and such flowsheets are seldom reported in the e-waste literature. The potential flowsheets need to be assessed considering socio-techno-economic considerations to yield the best available technologies (BAT). In the wider context, the results of this work could be useful for achieving the United Nations sustainable development goals.

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Improving bromine fixation in co-pyrolysis of non-metallic fractions of waste printed circuit boards with Bayer red mud

Cited by 62 publications

References 37 publications

Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs)

Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs)

Debromination with Bromine Recovery from Pyrolysis of Waste Printed Circuit Boards Offers Economic and Environmental Benefits

Assessment of Pre-Treatment Techniques for Coarse Printed Circuit Boards (PCBs) Recycling

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