Analysis of rejects from waste printed circuit board processing as an alternative fuel for the cement industry

2020 ◽  
pp. 0734242X2095284
Author(s):  
Amit Kumar ◽  
Maria E Holuszko ◽  
Travis Janke
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Precious Metals ◽  
Calorific Value ◽  
Alternative Fuel ◽  
Organic Content ◽  
Cement Industry ◽  
Circuit Board ◽  
Printed Circuit

Waste Printed circuit boards (PCBs) are one of the most valuable and recycled components of electronic waste due to the presence of precious metals such as copper, silver, gold and palladium. The rejects of the PCB recycling process, named non-metal fraction (NMF) have continuously been sent to landfills. Several researchers have proposed alternative use of NMF as secondary materials such as fillers in composites or as adsorbent. This study is focused on the potential application of the PCB recycling rejects as waste-derived fuel or alternative fuel in the cement industry. Approximately 2 million metric tonnes (Mt) of this waste was produced in 2014 globally and estimated to reach 6.5 million Mt in 2050. The presence of high organic matter in the NMF renders it useful as an alternative fuel. The organic content of the NMF could also potentially be increased using gravity separation and thus increasing its net calorific value. The study showed that the NMF could provide up to 21 MJ kg-1 of heating value with low heavy metal and ash concentration. A comparison with other waste-derived fuel sources is also presented in the paper.

Comparison of Leaching Processes of Gold and Copper from Printed Circuit Boards of Waste Mobile Phone

2014 ◽  
Vol 955-959 ◽  
pp. 2743-2746 ◽  
Author(s):  
Jian Feng Yin ◽  
Si Hui Zhan ◽  
He Xu
Keyword(s):  
Mobile Phone ◽  
Inductively Coupled Plasma ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Precious Metals ◽  
Optical Emission ◽  
Optimal Choice ◽  
Circuit Board ◽  
Printed Circuit

Waste mobile phone has become the largest number of electronic waste, and recycling of metals from mobile phone would ensure resource recycling and reduce environmental degradation. Based on the contents of metals analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), containing copper and precious metals such as gold, the paper compared the extraction processes of gold, copper from waste mobile phone printed circuit board (PCB). In this study, two processes, nitric acid and thiourea (NT), sulfuric acid-hydrogen peroxide and iodine (SAHPI) were used to leach copper and gold, respectively. The recovery rate of copper was found to be 96.42%, and 94.3% of the gold was leached in the former process. Similar trends were obtained for the leaching of copper and gold in the latter process, but it was lower that about 95.27% of copper was recycled, while 93.4% of gold were leached. Both the two processes were nontoxic and non-cyanide system. However, thiourea is not stable and easy to decompose in alkaline solution, and the technology has disadvantage of instability. Iodine leaching on the other hand is comparatively a environmental process. Therefore, the optimal choice is the combined process of SAHPI method, while further research is required to develop cost effective and environmentally friendly processes.

scholarly journals Estimating Recycling Return of Integrated Circuits Using Computer Vision on Printed Circuit Boards

2021 ◽  
Vol 11 (6) ◽  
pp. 2808
Author(s):  
Leandro H. de S. Silva ◽  
Agostinho A. F. Júnior ◽  
George O. A. Azevedo ◽  
Sergio C. Oliveira ◽  
Bruno J. T. Fernandes
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Decision Criterion ◽  
Economic Feasibility ◽  
Electronic Equipment ◽  
Circuit Board ◽  
Mechanical Recycling ◽  
Printed Circuit

The technological growth of the last decades has brought many improvements in daily life, but also concerns on how to deal with electronic waste. Electrical and electronic equipment waste is the fastest-growing rate in the industrialized world. One of the elements of electronic equipment is the printed circuit board (PCB) and almost every electronic equipment has a PCB inside it. While waste PCB (WPCB) recycling may result in the recovery of potentially precious materials and the reuse of some components, it is a challenging task because its composition diversity requires a cautious pre-processing stage to achieve optimal recycling outcomes. Our research focused on proposing a method to evaluate the economic feasibility of recycling integrated circuits (ICs) from WPCB. The proposed method can help decide whether to dismantle a separate WPCB before the physical or mechanical recycling process and consists of estimating the IC area from a WPCB, calculating the IC’s weight using surface density, and estimating how much metal can be recovered by recycling those ICs. To estimate the IC area in a WPCB, we used a state-of-the-art object detection deep learning model (YOLO) and the PCB DSLR image dataset to detect the WPCB’s ICs. Regarding IC detection, the best result was obtained with the partitioned analysis of each image through a sliding window, thus creating new images of smaller dimensions, reaching 86.77% mAP. As a final result, we estimate that the Deep PCB Dataset has a total of 1079.18 g of ICs, from which it would be possible to recover at least 909.94 g of metals and silicon elements from all WPCBs’ ICs. Since there is a high variability in the compositions of WPCBs, it is possible to calculate the gross income for each WPCB and use it as a decision criterion for the type of pre-processing.

scholarly journals Behavior of Waste Printed Circuit Board (WPCB) Materials in the Copper Matte Smelting Process

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 887 ◽  
Author(s):  
Xingbang Wan ◽  
Jani Fellman ◽  
Ari Jokilaakso ◽  
Lassi Klemettinen ◽  
Miikka Marjakoski
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Precious Metals ◽  
Melting Behavior ◽  
Inert Atmosphere ◽  
Circuit Board ◽  
Copper Smelting ◽  
Smelting Process ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

The amount of waste electrical and electronic equipment (WEEE) in the world has grown rapidly during recent decades, and with the depletion of primary ores, there is urgent need for industries to study new sources for metals. Waste printed circuit boards (WPCB) are a part of WEEE, which have a higher concentration of copper and precious metals when compared to primary ore sources. PCB materials can be processed using pyrometallurgical routes, and some industrial processes, such as copper flash smelting, have utilized this type of waste in limited amounts for years. For the purpose of recycling these materials through smelting processes, this work studied the behavior of WPCB scrap when dropped on top of molten slag. A series of experiments was carried out during this research at a temperature of 1350 °C, in an inert atmosphere with different melting times. The time required for complete melting of the PCB pieces was 2–5 min, after which molten alloy droplets containing Cu, Pb, Sn, Ni, Au, and Ag formed and started descending toward the bottom of the crucible. The ceramic fraction of the PCB material mixed with slag and the polymer fraction was pyrolyzed during the high-temperature experiments. The results give an understanding of PCB melting behavior and their use as a part of the smelting furnace feed mixture. However, more research is needed to fully understand how the different elements affect the process as the amount of PCB in the feed increases. The physical behavior and distribution of PCB materials in fayalite slag during the smelting process are outlined, and the results of this work form a basis for future studies about the chemical reaction behavior and kinetics when PCB materials are introduced into the copper smelting process.

Pyrolysis of Waste Printed Circuit Board Particles

2015 ◽  
Vol 4 (2) ◽  
pp. 70-75
Author(s):  
Şule Atasever ◽  
Pınar A. Bozkurt ◽  
Muammer Canel
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Circuit Board ◽  
Electronic Apparatus ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Waste Printed Circuit Board ◽  
Different Temperatures ◽  
Apparatus And Instruments

Electrical and electronic apparatus and instruments which are obsolete value in use or completion of the life can be defined as e-waste. E-waste is one of the fastest growing types of hazardous waste. Printed circuit boards a major component of this waste. In this study, printed circuit board particles of mobile phone (MPCB) were used as electronic waste. MPCB waste was obtained from a local electronic waste factory. The elemental analysis and ICP-MS analysis were performed on these electronic wastes and thereafter pyrolysis runs were carried out between 500 and 900°C in a horizontal furnace. The liquid yields were determined and compared at different temperatures.

scholarly journals Recovery of Metals from Printed Circuit Boards By Means of Electrostatic Separation

2020 ◽  
Vol 28 (4) ◽  
pp. 213-219
Author(s):  
Dawid Franke ◽  
Tomasz Suponik ◽  
Paweł M. Nuckowski ◽  
Klaudiusz Gołombek ◽  
Kamila Hyra
Keyword(s):  
Waste Management ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Negative Impact ◽  
Electronic Waste ◽  
Circuit Board ◽  
Circuit Boards ◽  
Electrostatic Separation ◽  
Printed Circuit

AbstractWithout the use of appropriate recycling technologies, the growing amount of electronic waste in the world can be a threat to the development of new technologies, and in the case of improper waste management, may have a negative impact on the environment. This is due to the fact that this waste contains large amounts of valuable metals and toxic polymers. Therefore, it should be recycled in accordance with the assumptions of the circular economy. The methods of mechanical recovery of metals from electronic waste, including printed circuits, may be widely used in the future by waste management companies as well as metal production and processing companies. That is why, a well-known and easily applicable electrostatic separation (ES) method was used to recover metals from printed circuit boards. The grain class of 0.32 - 0.10 mm, obtained after grinding the boards, was fed to a separator. Feed and separation products were analyzed by means of ICP-AES, SEM/EDS and XRD. The concentrate yield obtained after electrostatic separation amounted to 32.3% of the feed. Its density was 11.1 g/cc. Out of the 91.44% elements identified in the concentrate, over 90% were metals. XRD, SEM observations and EDS analysis confirmed the presence of non-metallic materials in the concentrate. This relatively high content of impurities indicates the need to grind printed circuit board into grain classes smaller than 0.32-0.10 mm.

Study on the Promotion Effect of Microwave-Metal Discharge on the Microwave Pyrolysis of Electronic Waste

2015 ◽  
Vol 1088 ◽  
pp. 843-847 ◽  
Author(s):  
Jing Sun ◽  
Wen Long Wang ◽  
Chun Yuan Ma ◽  
Qin Yan Yue
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Absorption Capacity ◽  
Circuit Board ◽  
Microwave Pyrolysis ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Metal Discharge ◽  
In The Beginning

This paper discussed the role of microwave-metal discharge on the microwave induced pyrolysis of electronic waste. Two kinds of waste printed circuit boards (WPCB) were selected as the representatives of electronic waste and their pyrolysis processes under both conventional and microwave heating schemes were studied comparatively to reveal the effect of metal discharge. The copper-clad laminated printed circuit board (PCB) is deficient in absorbing microwaves, leading to inefficient microwave pyrolysis of this kind of electronic waste. The discharge caused by introducing metalliferous materials with metal tips or corners in the electromagnetic fields can result in high local temperature and complement the deficiency in the microwave absorption. The pyrolytic process can be promoted greatly by the thermal effect of discharge in the beginning and the enhanced consequent wave-absorption capacity as a result of the generated pyrolytic coke.

scholarly journals Leaching of gold and silver from printed circuit board of mobile phones

2015 ◽  
Vol 68 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Patrícia Melo Halmenschlager Petter ◽  
Hugo Marcelo Veit ◽  
Andréa Moura Bernardes
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Precious Metals ◽  
Circuit Board ◽  
Circuit Boards ◽  
Aqua Regia ◽  
Printed Circuit ◽  
Ammonium Thiosulfate

Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.

scholarly journals Use of gravity separation in metals concentration from printed circuit board scraps

2014 ◽  
Vol 67 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Hugo Marcelo Veit ◽  
Nichele Cristina de Freitas Juchneski ◽  
Janine Scherer
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Economic Value ◽  
Circuit Board ◽  
Environmental Damage ◽  
Circuit Boards ◽  
New Materials ◽  
Printed Circuit ◽  
Complex Process

The amount of solid waste generated by all segments of society has increased in past decades. Annually, in Brazil, 96,000 tonnes of electronic scrap are generated from computers. The incorrect disposal of this waste creates environmental damage, generating loss of materials that could be reused and / or recycled, reducing the extraction of recyclable materials to produce new materials. The printed circuit boards (PCB) represent approximately 30% of the electronic waste generated and its recycling is a complex process, but very important for the recovery of metals of high economic value. Industrial processes for the recovery of metals from PCB are based on pyrometallurgy and hydrometallurgy. In both cases, it is possible to carry out a pretreatment that involves the use of mechanical processes. Therefore, for this paper, the concentration of the metallic fraction of PCB through the use of a Mozley concentrator was enabled. The results show that it is possible to obtain significant quantities of metals such as copper (concentration 85%), tin (95%), and silver (98%) in the fractions of interest.

Effect of Temperature in Carbothermic Reduction of Indonesian Limonite Ore Using Printed Circuit Boards as Reducing Agent

2020 ◽  
Vol 1009 ◽  
pp. 155-161
Author(s):  
Reza Miftahul Ulum ◽  
Andy Kurnia Wicaksana ◽  
Faizinal Abidin
Keyword(s):  
Carbothermic Reduction ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Reduction Process ◽  
Exothermic Peak ◽  
Reducing Agent ◽  
Circuit Board ◽  
Effect Of Temperature ◽  
Printed Circuit

In recent years, there have been increases in the production of electronic waste, such as Printed Circuit Board (PCB), because of the rapid advancement of technology. PCBs are highly valuable, as they contain metals such as copper, silver, and gold. This research aims to investigate the feasibility of using PCB, discarded from laptops as the reducing agent for the carbothermic reduction process of Indonesian limonite ore and the effect of temperature on the carbothermic reduction process, specifically on the phase transformation and the differences in microstructure. Based on the TGA-DSC result, the mixture of limonite and PCB have three endothermic peaks at 90 °C, 290 °C, 450 °C and one exothermic peak at 910 °C, whereas the mixture of limonite and coal has the same trends but the exothermic peak occurs at 1070 °C. To investigate the effect of PCB powder on the reduction of limonite ore, a carbothermic reduction experiment was carried out through the mixing of 8.0 g of limonite ore with 2.0 g of PCB powder (20 wt.%), which was then further compacted. The experiment was carried out at temperature variations of 700 °C, 900 °C, 1100 °C for 1 hour in an inert atmosphere furnace. The products of the reduction process were magnetically separated and then characterized using SEM/EDS and XRD to evaluate the differences in microstructure. This research found that PCB powder is a feasible reducing agent for the reduction of limonite ore.

Dielectric Breakdown in Printed Circuit Boards at Elevated Temperatures

1996 ◽  
Author(s):  
P. Singh ◽  
G.T. Galyon ◽  
J. Obrzut ◽  
W.A. Alpaugh
Keyword(s):  
Experimental Data ◽  
Thermal Degradation ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Elevated Temperatures ◽  
Dielectric Breakdown ◽  
Circuit Board ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Data Matching

Abstract A time delayed dielectric breakdown in printed circuit boards, operating at temperatures below the epoxy resin insulation thermo-electrical limits, is reported. The safe temperature-voltage operating regime was estimated and related to the glass-rubber transition (To) of printed circuit board dielectric. The TG was measured using DSC and compared with that determined from electrical conductivity of the laminate in the glassy and rubbery state. A failure model was developed and fitted to the experimental data matching a localized thermal degradation of the dielectric and time dependency. The model is based on localized heating of an insulation resistance defect that under certain voltage bias can exceed the TG, thus, initiating thermal degradation of the resin. The model agrees well with the experimental data and indicates that the failure rate and truncation time beyond which the probability of failure becomes insignificant, decreases with increasing glass-rubber transition temperature.

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