scholarly journals A GROUND OF BOOTY OF COPPER IS FROM EFFLUENTS

2018 ◽  
pp. 94-98
Author(s):  
A.A. Nester
Keyword(s):  
Soil Contamination ◽  
Printed Circuit Boards ◽  
Raw Materials ◽  
Copper Production ◽  
Circuit Boards ◽  
Mathematical Methods ◽  
Etching Solution ◽  
Printed Circuit ◽  
The Given ◽  
Copper Ores

Purpose. The modern state with the booty of copper ores andproduction of copper are considered in Ukraine.The task of the article is to carry out a forecast of soil contamination with slurries of printed circuit boards and electroplating. This allows to improve the ecological safety of territories of enterprises producing boards and electroplating. The methodology. The article uses mathematical methods of calculation according to the theory of porous media physicochemical hydrodynamics. This process is described by the equation of movement and conservation of mass of matter in vertical shifts. Findings. The main result of the given work is to improve the method for determining consequences of soil contamination by sludge from PCB and electroplating producing shops. The originality. To avoid the accumulation of sludge in the territory of enterprises we propose to use the technology of spent etching solution regeneration where the selected metal is used as secondary raw materials for copper production and recovered solution is reused for etching printed circuit boards. This way almost no sludge is generated, or their quantity is negligible. Practical implications. The article helps to understand the harmfulness of sludge storage in the enterprise and shows the working method to develop recycling technologies and reuse etching solution during etching PCB.

scholarly journals Optimization of copper ammonium etching composition solutions in the production of printed circuit boards

2020 ◽  
Vol 61 (3) ◽  
pp. 36-42
Author(s):  
Ekaterina P. Boyarskih ◽  
◽  
Ludmila A. Brusnitsina ◽  
Elena I. Stepanovskih ◽  
Tatiana A. Alekseeva ◽  
...  
Keyword(s):  
Ammonium Chloride ◽  
Copper Foil ◽  
Printed Circuit Boards ◽  
Etching Rate ◽  
Metallic Copper ◽  
Etching Process ◽  
Foil Thickness ◽  
Circuit Boards ◽  
Etching Solution ◽  
Printed Circuit

Etching in the production of printed circuit boards is the process of chemical destruction of metal (mainly copper) as a result of the action of liquid or gaseous etchers on the areas of the surface of the workpiece unprotected by a protective mask (etching resist). Copper foil etching is used to form a conductive pattern of PCB by removing copper from unprotected etching resist areas. This is one of the main operations of manufacturing the PCB, since a pattern of printed elements is formed on it. During the etching process, unprotected copper from the printed circuit board by means of an oxidizer is converted into an ionic state and is connected to hydroxide and ammonium chloride, forming a solution of the copper-ammonia complex, which after oxidation with air ensures dissolution of copper. The etching solution in question contains three components: copper(II) chloride, which when reacted with metallic copper is an oxidant; Ammonia forming ammonia complexes with copper(II) and allowing copper(II) to be kept in a soluble state; Ammonium chloride, which accelerates the etching process and keeps the solution stable. Increased efficiency of copper etching in ammonia solutions is achieved at change of its composition. The purpose of the work was to study the etching rate of copper and to change the concentration of the etching solution depending on the initial concentration of copper(II) chloride in the original etching solution, as well as the effect of the pH of the etching solution on the etching rate of metallic copper. The double-sided foamed fiberglass was used as a starting material to study the etching process. The foil thickness was 30 μm. Etching of the copper foil was carried out with constant stirring of the sample in solution. The concentration of copper ions in the solution was determined by spectrophotometric method from the value of optical density of the ammonia-containing solution (D). The thickness of the release layer of metallic copper was determined by gravimetric method. As a result of this work, it has been shown that changes in the concentration of copper(II) in the solution, the etching rate, the thickness of the release coating and the pH of the solution can be used to characterize the copper etching process. It is established that the greatest increase in concentration of Cu2+ in solution is observed within the first minute with its further gradual slow increase. More obvious increase in concentration of Cu2+ in solution is observed at concentration of Cu2+ in initial solution 80 gl−1. At increase in concentration of chloride of copper(II) in solution from 40 gl−1 to values 100 gl−1 sharp increase in speed of etching of copper is observed. A further increase in copper(II) chloride concentration results in a decrease in etching rate. The pH of the etching solution is determined by the ratio of ammonia and ammonium chloride. This is due to the formation of a buffer mixture in the solution. Increasing the pH of the solution results in an increase in the etching rate followed by a decrease in the etching rate.

scholarly journals Determination of Metals’ Content in Components Mounted on Printed Circuit Boards from End-of-Life Mobile Phones

Recycling ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 20
Author(s):  
Tadeusz Gorewoda ◽  
Marcus Eschen ◽  
Jadwiga Charasińska ◽  
Magdalena Knapik ◽  
Sylwia Kozłowicz ◽  
...  
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Raw Materials ◽  
Absorption Spectrometry ◽  
Atomic Emission ◽  
Emission Spectrometry ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Valuable Metals

The electronic components mounted on the printed circuit boards (PCBs) of mobile phones represent a resource that is rich in metals, and after separation from the boards, these components could be considered secondary raw materials. The concentrations of the valuable metals are insignificant when compared with those of complete PCBs; however, they could be significantly higher in a fraction formed from the separated components. This study focused on the analysis of Ag, Au, Cu, Nd, Nb, Ni, Pb, Pd, Sn, and Ta in fractions produced by the separation of all the components mounted on PCBs from several types of mobile phones. Atomic absorption spectrometry, atomic emission spectrometry, and mass spectrometry techniques were utilized, and a comparison of five older models of “brick” phones and five modern smartphones was conducted. Additionally, 50 kg of PCBs from the current recycling market were analyzed in the same way to create a summary of the current recycling stream.

scholarly journals Mathematical methods for physical layout of printed circuit boards: an overview

OR Spectrum ◽  
2007 ◽  
Vol 30 (3) ◽  
pp. 453-468 ◽  
Author(s):  
Nadine Abboud ◽  
Martin Grötschel ◽  
Thorsten Koch
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Mathematical Methods ◽  
Printed Circuit ◽  
Physical Layout

scholarly journals Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 281
Author(s):  
Tomasz Suponik ◽  
Dawid M. Franke ◽  
Paweł M. Nuckowski ◽  
Piotr Matusiak ◽  
Daniel Kowol ◽  
...  
Keyword(s):  
Cryogenic Temperature ◽  
Printed Circuit Boards ◽  
Raw Materials ◽  
Microscopic Analysis ◽  
Sieve Analysis ◽  
Circuit Boards ◽  
Electrostatic Separation ◽  
Printed Circuit ◽  
Valuable Metals ◽  
The Impact

This paper analyses the impact of the method of grinding printed circuit boards (PCBs) in a knife mill on the efficiency and purity of products obtained during electrostatic separation. The separated metals and plastics and ceramics can be used as secondary raw materials. This is in line with the principle of circular economy. Three different screen perforations were used in the mill to obtain different sizes of ground grains. Moreover, the effect of cooling the feed to cryogenic temperature on the final products of separation was investigated. The level of contamination of the concentrate, intermediate, and waste obtained as a result of the application of fixed, determined electrostatic separation parameters was assessed using ICP-AES, SEM–EDS, XRD, and microscopic analysis as well as specific density. The yields of grain classes obtained from grinding in a knife mill were tested through sieve analysis and by using a particle size analyser. The test results indicate that using a knife mill with a 1 mm screen perforation along with cooling the feed to cryogenic temperature significantly improves the efficiency of the process. The grinding products were characterised by the highest release level of the useful substance—metals in the free state. The purity of the concentrate and waste obtained from electrostatic separation was satisfactory, and the content of the intermediate, in which conglomerates of solid metal–plastic connections were present, was very low. The yield of concentrate and waste amounted to 26.2% and 71.0%, respectively. Their purity, reflected in the content of the identified metals (valuable metals), was at the level of 93.3% and 0.5%, respectively. In order to achieve effective recovery of metals from PCBs by means of electrostatic separation, one should strive to obtain a feed composed of grains <1000 μm and, optimally, <800 μm.

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