Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation
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 pr...
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| Format: | Article |
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MDPI AG
2021-03-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/11/3/281 |
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| author | Tomasz Suponik Dawid M. Franke Paweł M. Nuckowski Piotr Matusiak Daniel Kowol Barbara Tora |
| author_facet | Tomasz Suponik Dawid M. Franke Paweł M. Nuckowski Piotr Matusiak Daniel Kowol Barbara Tora |
| author_sort | Tomasz Suponik |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T13:23:50Z |
| format | Article |
| id | doaj.art-0f3b9c9d758242e688dda3134e831ee4 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T13:23:50Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-0f3b9c9d758242e688dda3134e831ee42023-11-21T09:46:02ZengMDPI AGMinerals2075-163X2021-03-0111328110.3390/min11030281Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic SeparationTomasz Suponik0Dawid M. Franke1Paweł M. Nuckowski2Piotr Matusiak3Daniel Kowol4Barbara Tora5Institute of Mining, Faculty of Mining, Safety Engineering and Industrial Automation, Silesian University of Technology, 2 Akademicka Street, 44-100 Gliwice, PolandInstitute of Mining, Faculty of Mining, Safety Engineering and Industrial Automation, Silesian University of Technology, 2 Akademicka Street, 44-100 Gliwice, PolandMaterials Research Laboratory, Faculty of Mechanical Engineering, Silesian University of Technology, 18A Konarskiego Street, 44-100 Gliwice, PolandKOMAG Institute of Mining Technology, 37 Pszczynska, 44-101 Gliwice, PolandKOMAG Institute of Mining Technology, 37 Pszczynska, 44-101 Gliwice, PolandFaculty of Mining and Geoengineering, AGH University of Science and Technology, 30 Mickiewicza, 30-059 Kraków, PolandThis 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.https://www.mdpi.com/2075-163X/11/3/281metals recoveryprinted circuit boardcryogenic grindingelectrostatic separationatomic emission spectroscopyscanning electron microscopy (SEM) |
| spellingShingle | Tomasz Suponik Dawid M. Franke Paweł M. Nuckowski Piotr Matusiak Daniel Kowol Barbara Tora Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation Minerals metals recovery printed circuit board cryogenic grinding electrostatic separation atomic emission spectroscopy scanning electron microscopy (SEM) |
| title | Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation |
| title_full | Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation |
| title_fullStr | Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation |
| title_full_unstemmed | Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation |
| title_short | Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation |
| title_sort | impact of grinding of printed circuit boards on the efficiency of metal recovery by means of electrostatic separation |
| topic | metals recovery printed circuit board cryogenic grinding electrostatic separation atomic emission spectroscopy scanning electron microscopy (SEM) |
| url | https://www.mdpi.com/2075-163X/11/3/281 |
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