Printed Circuit Board Powder Research Articles

Property Enhancement of Waste Printed Circuit Boards Powders Reinforced Polypropylene by In Situ Magnesium Hydroxide Impregnation from Waste Lye.

Using alkali pretreatment can effectively remove residual variable-valence metals from non-metallic powder (WPCBP) in waste printed circuit boards. However, substantial amounts of waste lye are generated, which causes secondary pollution. On this basis, this study innovatively utilized waste alkali lye to prepare nano-magnesium hydroxide. When the dispersant polyethylene glycol 6000 was used at a dosage of 3 wt.% of the theoretical yield of magnesium hydroxide, the synthesized nano-magnesium hydroxide exhibited well-defined crystallinity, good thermal stability and uniform particle size distribution, with a median diameter of 197 nm. Furthermore, the in situ method was selected to prepare WPCBP/Mg(OH)2 hybrid filler (MW) and the combustion behavior, thermal and mechanical properties of PP blends filled with MW were evaluated. The combustion behavior of the PP/MW blends increased with the increasing hybrid ratio of Mg(OH)2, and the MW hybrid filler reinforced PP blends showed better thermal and mechanical properties compared to the PP/WPCBP blends. Furthermore, the dynamic mechanical properties of the PP/MW blends were also increased due to the improved interfacial adhesion between the MW fillers and PP matrix. This method demonstrated high economic and environmental value, providing a new direction for the high value-added utilization of WPCBP.

Effect of e-waste nanofillers on the mechanical, thermal, and wear properties of epoxy-blend sisal woven fiber-reinforced composites

Abstract Lignocellulosic biomass extracted from plants that contain rich amounts of cellulose, hemicellulose, and lignin content can replace synthetic fibers in many engineering applications and is biodegradable. However, e-waste is rapidly evolving into one of the most serious environmental issues in the world owing to the presence of several toxic compounds that can contaminate the environment and pose a threat to human health. Printed circuit boards (PCBs) are one of the major components available in e-waste. In this research work, waste PCB (WPCB) powder is mixed in suitable proportions of 5%, 10%, 15%, and 20% with a lignocellulosic sisal woven fabric fiber mat, and blended with epoxy resin using the vacuum-assisted hand lay-up method. To determine the effect of particle size on the fabricated composites, mechanical, thermal, water absorption, surface roughness, and wear tests were conducted. It was found that the composition that contains 15% nanofiller composites gave better results in mechanical testing than the composition that contains 10% microfiller composites. Pin-on disc wear test and differential scanning calorimetric thermal test results show that 10% microfiller composites show better outcome results than 15% nanofiller composites. Testing values indicate that lignocellulosic sisal fiber composites with WPCB nano- and microfillers can be substituted for many engineering applications instead of being disposed of in landfills.

Corrosion Resistant Coating from Nano Printed Circuit Board Powder for the Reinforced Concrete Structures

Corrosion in steel leads to the deterioration of reinforced concrete structures due to chemical reactions between steel and its surrounding atmosphere. In this paper, a novel anticorrosive powder was derived from the waste Printed Circuit Board (PCB) and manually coated on the steel rebar of the reinforced concrete specimen. The corrosion-resistant efficiency of the developed nano PCB-coating on the steel bars was studied by polarization, electrochemical impedance spectroscopy, and accelerated corrosion technique. Also, the applicability of the nano PCB-coated rebar as reinforcement in the concrete environment was investigated. From the results, it was observed that the nano PCB-coated specimens exhibited 3.5 times reduced rate of corrosion and lost only 46.15% strength and 52.5% diameter under the accelerated rate of 6 V after 48 hours. The presence of nano PCB powder improved the corrosion-resistant behaviour of the steel rebar by 1.65 times of the noncoated specimen. Also, the nano PCB-coating reduced the loss in residual yield strength of the corroded steel rebar by 32% lesser than the noncoated specimens and exhibited similar corrosion-resistant properties as that of the existing zinc coating. In addition to the corrosion resistance, the nano PCB-coated steel rebar exhibited almost similar adhesion with concrete as that of the commercial zinc coating which is 7% lower than uncoated steel rebars. It was inferred from this research work that the proposed anticorrosive coating prepared from the waste nano PCB powder showed better corrosion-resistant behaviour and reduced the overall cost of coating by 42%, which ensures economy and serviceability.

Production and characterization of a polysaccharide/polyamide blend from Pseudomonas atacamensis M7D1 strain for enhanced oil recovery application

Bio-based polymers have better salt and temperature tolerance than most synthetic polymers. The biopolymer solutions have high viscosity, which can lead to reducing the fingering effect and soaring the oil recovery rate. This work aims to produce and characterize a biopolymer from Pseudomonas Atacamensis M7D1 strain, modify the biopolymer yield using Printed Circuit Boards (PCBs) powder as an outer tension in the growth medium, and finally, evaluate the produced biopolymer function for Enhanced Oil Recovery (EOR) purposes. Using PCBs powder to trigger bacteria for higher production yield increases the biopolymer production rate eleven times higher than pure growth medium without additives. Different analyses were performed on the biopolymer to characterize its properties; Gel Permeation Chromatography (GPC) indicated that the produced biopolymer has an average molecular weight of 3.6 × 105 g/mol. This macromolecule has high thermal resistivity and can tolerate high temperatures. Thermal analysis (TGA/DSC) shows only 69.27 % mass lost from 25 °C to 500 °C. The viscosity of 0.5 wt% biopolymer solution equals 3cp, 3 times higher than water. The glass micromodel flooding result shows that biopolymer solution with 0.5 wt% concentration has a 42 % recovery rate which is 24 % higher than water flooding.

Base Metals Extraction from Printed Circuit Boards by Pressure Acid Leaching

Printed circuit boards (PCBs) are a valuable source of raw materials for metal recycling considering that base metal concentration analyses have confirmed that PCB powders are multimetallic in nature and contain high concentrations of Cu, Zn, Ni, and Fe. Given that minerals are not renewable resources, these metals can be recycled through hydrometallurgical processes. In this study, we determined that 2 M sulfuric acid, 0.55 MPa oxygen pressure, and a temperature of 90 °C represent the optimal conditions for leaching of Cu, Zn, and Ni of PCBs, obtaining the highest observed values of recovery of greater than 90% for Zn and 98% for Cu and Ni. The characterization of PCBs by SEM–EDS analyses showed that plates mainly consist of Cu, Ni, and Zn. PCBs can be seen as a potential secondary resource for the recovery of copper, nickel, and zinc. The best potential and pH conditions for the extraction of Cu, Zn, and Ni were also determined on the basis of thermodynamic diagrams.

Effects of waste printed circuit board powder on strength, durability and microstructure of cement-based materials

A large number of waste printed circuit boards(WPCB) have caused extremely serious pollution problems to the environment. Two different particle sizes of waste printed circuit boards powders are incorporated into the cement-based material as an admixture to study its effect on the mechanical strength and durability of the cement-based material. The results show that WPCB powder can improve the compressive strength and flexural strength of cement-based materials. At the same time, WPCB powder can improve the freeze-thaw resistance and sulfate corrosion resistance of cement-based materials. The study also finds that when the mechanical strength and durability of the mortar are optimal, the content of fibrous WPCB powder is 1%, while the content of granular WPCB powder is 2.5%. The article also analyzes the improvement mechanism of WPCB powder on the mechanical properties and durability of cement mortar through porosity test, FTIR test and SEM test. The test results provide further theoretical research on the application of waste circuit boards in cement-based materials, and provide a new solution for reducing the pollution of WPCB to the environment.

Facile path for copper recovery from waste printed circuit boards via mechanochemical approach

Recycling copper (Cu0) from waste printed circuit boards (PCBs) is a prevalent challenge. Here, we propose a new pathway and reveal mechanisms for recovering Cu0 from waste PCBs via a mechanochemical approach. The successful application of mechanical force avoids using inorganic acid in the Cu0 recovery process. Our work demonstrates that ferric chloride (FeCl3) was superior to ferric sulfate and ferric nitrate as a solid-phase reagent for Cu0 recovery due to chloride complexation. Under the induction of mechanical force, the Cu0 in the waste PCBs was oxidized by Fe3+ and complexed by Cl¯ to form a meta-stable cuprous chloride, which was susceptible to leaching in an acidic liquid-phase system constructed by hydrolysis of ferric salt. Further mechanism analysis reveals that in the mechanochemical solid-phase reaction, Cu0, metallic impurities, metal oxides, and carbon materials from waste PCBs could also reduce Fe3+ to Fe2+. The optimum conditions for Cu0 recovery from waste PCB powder with FeCl3 as a solid-phase reagent were: rotational speed of 500 rpm, Cu0:Fe3+ molar ratio of 1:20, and reaction time of 120 min, achieving the highest recovery of 99.6 wt%. This study presents a facile path for Cu0 recovery from waste PCBs for resource circulation.

Fabrication and Mechanical Properties of High-Durability Polypropylene Composites via Reutilization of SiO2 In-Situ-Synthesized Waste Printed Circuit Board Powder.

This paper focuses on the characterization of the physico-chemical properties, surface modification, residual copper content and in situ hybrid inorganic particle modification of polypropylene (PP) composites reinforced by waste printed circuit board powder (WPCBP). A series of WPCBP/SiO2 hybrids (TSW) were prepared by a sol–gel method at different pH values. Characterization results revealed the in situ generation of SiO2 on the surface of WPCBP, and showed that with an increase in pH value, the size of SiO2 particles increased gradually and the copper content decreased in the TSW powder. The mechanical properties, oxidation induction time (OIT) and thermal properties of PP composites were improved by reinforcement with TSW, which might be ascribed to the formation of serrated interfaces. This work not only develops a powerful method to enhance the properties of PP/WPCBP composites, but also provides an environmentally sustainable approach to the high-added-value reutilization of WPCBP.

Novel Development of Corrosion Resistant Paint Using Printed Circuit Board from Modern Electronic Wastes

The growth in the industrial technology and communication sectors has enhanced the usage of electronic gadgets exponentially. Thus, it becomes highly essential to find new solution to utilize or dispose these e-wastes, in order to reduce the e-waste generation. Various reports mentioned that the major component of these e-wastes is their Printed Circuit Boards. Therefore, a new ideology is proposed to use these boards to produce a new coating with good corrosion resistance. At first the boards were separated from the discarded electronic appliances and various electrical elements were separated from these boards. Then the plain circuit boards are pulverized into fine particles and mixed with paint in 3 different proportions ranging from 1:4 to 1:2. The resulting mix was applied over the steel specimen and tested for corrosion resistance. The assessment was done in the aspects of contact angle, weight loss percentage, potentio dynamic polarization technique and electro chemical impedance spectroscopy. From the results it was clear that increase in the addition of printed circuit powder content in the corrosion proof paint coating enhanced the efficiency of the corrosion resistant behaviour 3.5 times than the specimen with uncoated steel specimens. This development of corrosion resistant behaviour of printed circuit powder was attributed from the inertness offered by the presence of silicon dioxides towards the corrosive fluids. Although, the coating of 1:2 proved to be optimum to protect the steel elements from the aggressive corrosion environment, by considering the workability aspects the 1:3 combination was suggested for the innovative development of anti-corrosion paint coating from the e-waste resources.
 HIGHLIGHTS
 
 Life cycles of every electronic wastes end with the hazardous challenging disposals
 Innovative utilizations of these electronic wastes for the corrosion resistant structural applications were detailed
 An anti corrosive coating for steel reinforcement was developed from the waste printed circuit boards
 Coating by printed circuit board powder enhanced 3.5 times more protection from the corrosion
 
 GRAPHICAL ABSTRACT

Recovery of copper and valuable metals from E-waste via hydrometallurgical method

Hydrometallurgical processes such as sulphuric acid leaching for recovering metal from waste from electrical and electronic equipment (WEEE), especially metal-rich printed circuit board (PCB), have provided a route for WEEE recycling. This study investigated the effect of the rate of oxidants (hydrogen peroxide) addition in volume per hour and temperature on the extraction of copper and other valuable metals from waste printed circuit board (WPCB). The optimum condition for the extraction of copper and valuable metal in sulphuric acid leaching were determined. The crushed and ground WPSB were leached in the sulphuric acid solution using hydrogen peroxide as an oxidant. The influence of two parameters; temperature (30 °C and 75 °C) and rate of oxidant addition (20 ml/hr and 60 ml/hr) were investigated against the extraction of copper (Cu, 30 wt%), aluminium (Al, 10.5 wt%), iron (Fe, 2.4 wt%), and zinc (Zn, 0.2 wt%). Scanning electron microscope-backscattered electron (SEM-BSE) image shows that shredding PCB into sizes smaller than 2.00 mm is sufficient to expose laminated copper components for an efficient sulphuric acid leaching process. The optimal condition for high extraction of copper was 1.5 M sulphuric acid, with 30 % hydrogen peroxide at rate 60 ml/hr, for ∼ 10 g of PCBs powder with a solid–liquid ratio of 1:10 for 1 h at temperature 75 °C.High percentage of extraction has been achieved in sulphuric acid media within 1 h (Cu (98 %), Al (52 %), Fe (52 %), Zn (92 %).

Copper recovery from waste printed circuit boards by the flotation-leaching process optimized using response surface methodology

ABSTRACT Recycling of waste printed circuit boards (PCBs) receives increasing attention due to abundant metallic resources and significant environmental threats. This work proposes a process for copper recovery from PCBs by froth flotation and oxidation leaching. Copper grade is improved from 38.70% to 68.34% with the recovery of 88.76% by froth flotation, and froth flotation is significantly influenced by copper liberation and particles dispersion of PCB powders. Process variables of oxidation leaching are examined by response surface methodology (RSM). A reliable mathematical model is obtained to predict the response as a function of independent variables and their interactions. Oxidation leaching is remarkably influenced by experimental variables, and the interactions between sulfuric acid and hydrogen peroxide are significant. Optimum conditions are achieved as sulfuric acid 1.0 mol/L, hydrogen peroxide 17%, temperature 50°C, and time 234 minutes, and the maximum leaching ratio of Cu is up to 99.94%, indicating that oxidation leaching is an effective method for Cu recovery from PCBs. Implications: Recycling of waste printed circuit boards (PCBs) receives increasing attention due to abundant metallic resources and significant environmental threats. This work proposes a novel process for copper recovery from PCBs by froth flotation and oxidation leaching. Froth flotation is efficient to enrich copper in metal fractions. Process variables of oxidation leaching are examined by response surface methodology (RSM). A reliable mathematical model is obtained to predict the response as a function of independent variables and their interactions. The froth flotation-oxidation leaching process is practicable and effective for copper recovery from waste printed circuit boards. This study significantly contributes to recycling metal resources from waste PCBs. We believe that this work will attract a broad readership and lead others to follow our approach.

Selective leaching of copper from waste printed circuit boards (PCBs) using glycine as a complexing agent

<p>In this research, the selective leaching of copper from waste printed circuit boards (PCBs) using glycine as a complexing agent was investigated. PCBs were pulverized and sieved, which allowed obtaining a PCBs powder of particle size fraction ≤ 1mm. The PCBs powder has been characterized by several techniques before and after leaching. In order to understand the copper extraction process, the reaction mechanisms, and to determine the optimal leaching parameters, the effects of a range of parameters during copper leaching were investigated, including leaching time, solid-to-liquid ratio, mechanical stirring rate, leaching temperature and glycine concentration. Copper leaching from PCBs waste powder was identified as a complex four-stage gas-liquid-solid process that is carried out slowly under ambient conditions. Glycine shows a very significant selectivity for copper during leaching process allowing dissolving copper from PCBs waste with a percentage of 92.8% under ambient conditions.</p>

Utilization of waste printed circuit board powder in concrete over conventional concrete

Generating waste in the current society is an emphasis to handle and segregate the E-waste materials to avoid the environmental impact and control the pollution. From the viewpoint of the construction industry, we care about the Manufacturing of cement industries and demolition waste results in evident pollution effects. The limelight of the research is eliminating the solid waste, and to engross this waste materials in the Concrete. The Printed Circuit Board (PCB) from all the Electrical devices is crushed and converted into ash which is utilized as the replacement for the fine aggregate to a certain percentage of replacement. The presence of silicon (Si) content in the PCB helps to fulfill the requirement as similar to the fine aggregate. Today lots of electrical and electronic waste from households like motherboard from the computer peripheral, video games, damaged or crashed television, home theatres, etc., the PCB which is destroyed from those products is not reused or recycled for the new products. On focus to the dumping of such electrical waste, it is processed and converted into fine powder to utilize as fine aggregate (FA) in the concrete specimens. Natural fine aggregate can be reduced to a certain limitation by using the crushed PCB powder as a replacement with 3%,5%, 10%, 15%, 20% and, 25% by weight. It is found that the strength of the concrete is improved and PCB can be partially used as fine aggregate replacement.

Study of the electrochemical behavior of printed circuit boards (PCBs) leaching solutions using glycine and copper recovery by electrodeposition from leachate solutions

The present work focuses on the study of the electrochemical behavior of printed circuit boards (PCBs) leaching solutions using glycine and copper recovery by electrodeposition from leachate solutions. The recovery is done in a minimum number of steps and under ambient conditions of temperature and pressure. Printed circuits boards (PCBs) were pulverized and sieved, which allowed to obtain a PCBs powder of particle size fraction ≤ 1 mm. X-ray fluorescence spectroscopy analysis was used for PCBs powder characterization before and after leaching. The copper leaching has been carried out from PCBs powder in the open air, under ambient conditions of temperature and pressure using a buffer solution of glycine. UV–Vis spectrophotometry and atomic absorption spectrophotometry were utilized to determine the efficiency of copper leaching. Cyclic sweep voltammetry and chronoamperometry were employed to obtain informations on the electrochemical behavior of metals in the leaching solutions and then compared to that of synthetic solutions containing Cu (II) ions. UV–Visible spectrophotometry was used to determine the nature of the formed complex. Electrodeposition technique was applied in order to recover copper in powder form. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were employed to examine the surface morphology and chemical composition of electrodeposited copper. The leaching solutions show exactly the same electrochemical behavior as the synthetic cupric solutions with two reduction peaks and a single oxidation peak, which demonstrates the high selectivity of glycine for copper. The chronoamperometric results confirm those obtained by voltammetry. UV–Visible spectrophotometry showed that the complex formed is [Cu(Gly)2] for the synthetic solutions as well as for the leachate solutions. Selective copper leaching was achieved with an efficiency of 92.5%. The resulting leachate solution was used directly for copper electrodeposition allowing the recovery of metallic copper as a pure product.

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

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.

Bioleaching of gold from waste printed circuit boards by alkali-tolerant Pseudomonas fluorescens

This paper evaluated the ability of Pseudomonas fluorescens to leach gold from waste printed circuit boards (WPCBs). Gold was recovered as gold-cyanide complex and cyanide was produced by Pseudomonas fluorescens. In this paper, the effect of pH on gold leaching efficiency was studied, the P.fluorescens was domesticated to grow at higher pH (pH 8 and 9), and the concentration of cyanide ions (CN−) available for bioleaching was increased in alkaline pH. The results showed that at 0.67% w/v pulp density of pretreated waste printed circuit boards powder, mutated bacteria attained gold biorecovery of 27% at pH 9, while the unadapted bacteria only 23% of bioleaching efficiency was achieved. Results revealed that bioleaching efficiency of gold from waste printed circuit boards decreased with the increase of pulp density, and 0.33% w/v pulp density had the maxnium influence to bioleaching efficiency of gold, which could reach 42%. In the two-step bioleaching process, the initial amounts of bacteria had a certain impact on the leaching efficiency, and 3.33% v/v of the initial bacterial liquid was a suitable addition. The type of substrate also affected the leaching bioleaching efficiency. The leaching efficiency in the later stage of gold leaching will be greatly improved to 54%, when glycine and methionine were added to the medium for cyanide production. This may be due to positive effect by the methionine, which could regulate the glycine pool of the cells.

Effects of decoppering pretreatment on accelerated weathering behaviors of waste printed circuit boards powders reinforced polypropylene composites

ABSTRACTWaste printed circuit boards powders (WPCBP), the critical by‐products in the dispose process of waste electrical and electronic equipment, were selected as reinforcing fillers in polypropylene (PP) composites, which brought forward a new way to reuse WPCBP for a sustainable world. However, the multivalent metals in WPCBP could accelerate the degradation of PP molecule chains. In this study, nitric acid was selected as copper removal to pretreat WPCBP, and most of the metals were removed after decoppering pretreatment, which was evidenced by X‐ray fluorescence (XRF). The ensuing compound was characterized by oxidation induction time, scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical analysis. As expected, the accelerate weathering behaviors of PP composite with nitric acid treated WPCBP were substantially improved, for instance, the notched impact strength and tensile strength of untreated PP/WPCBP composite after 21 days thermal aging were just 0.85KJ/m2 and 9.3 MPa, while the PP composite with 6 wt % nitric acid‐treated WPCBP was 3.47KJ/m2 and 32.1 MPa. We envisage this facile strategy, that is, using proper concentration of nitric acid to pretreat WPCBP could improve the accelerate weathering properties of PP/WPCBP composites, which would broaden the potential applications of WPCBP in polymer compounds. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48224.

Electrochemical extraction of tin and copper from acid leachate of printed circuit boards using copper electrodes

This paper presents new results for the recycling of electronic waste, specifically those from printed circuit boards (PCBs) of obsolete computers of the Federal University of Rio Grande do Norte. The main objective of this study is the comprehension of the extraction process of tin and cop per from PCBs by a hydrometallurgical route followed by electrodeposition using copper electrodes. PCBs powder were leached using 1N HNO3 and 3N HCl (aqua regia) aqueous solutions. The process permitted the extraction of all tin present on the PCBs. The electrodeposition processes were performed with currents from 0.5 to 1.5 A, at a constant time of 60 min, with and without mechanical stirring, and with different concentrations of leachate. The results showed that diluting the leachate favors the extraction of tin from the solution. At certain conditions we were able to extract approximately 100% of the tin, copper and lead present in the leachate.

Mechano-microbial systems: An ecofriendly approach for copper bioleaching from waste printed circuit board.

Waste printed circuit board (PCB) is attracting serious concerns because the recycling of its valuable metallic portion is made difficult by the existence of hazardous substances. The objective of the present study was to develop a simplified approach for copper bioleaching from waste PCB. In this context, we intended mechano-microbial systems symbolized as SET-I (spore suspension + potato dextrose broth medium + waste PCB powder), SET-II (pre-cultured until the logarithmic phase, without waste PCB powder), and SET-III (fungal metabolites produced at stationary phase). The results of bioleaching studies showed that the developed method achieved the highest copper leaching of 85% by the SET-III approach. This study provides an insight for bioleaching copper from waste PCB. Furthermore, this approach can be established as an ecofriendly method for copper bioleaching by using an integrated system.

A new chelating resin from waste printed circuit board powder

An aminated resin was prepared by using the waste printed circuit board(WPCB) powder-with brominated epoxy resin as the polymer matrix material- pretreated with acid and alkali- then modified using diethylenetriamine. A novel chelating resin containing a dithiocarbamate(DTC) group was synthetized with the reaction by the aminated resin- carbon disulfide and Sodium hydroxide. It was characterized by FTIR and 13C NMR. The adsorption effects of the modified materials on heavy metal ions were investigated, and the results showed that DTC-WPCB have well adsorption performance on Ag+.