The project is co-financed by REACT-EU funding for mitigating the consequences of the pandemic crisis.
Type: Specific Objective 1.1.1 "Improve research and innovation capacity and the ability of Latvian research institutions to attract external funding, by investing in human capital and infrastructure".1.1.1.1. measure “Industry-Driven Research”
Agreement No: 1.1.1.1/20/A/139
Duration: 2021. – 2023.
Project Leader: Institute of Solid State Physics, University of Latvia, Dr. Phys. Vladimirs Pankratovs.
Project partners:
- Rīgas Tehniskā Universitāte, Riga Technical University (RTU)
- SIA ZTF AERKOM
Total budget: 540 540,00 EUR
ISSP UL budget: 216 216,00 EUR
Project description:
General goal of the project: Development of suitable electrochemical recycling technology of electronic scrap (e-scrap) from printed circuit board (PCB) by alternating current (AC) of industrial frequency for the most complete extraction of all metallic components into solution and evaluation of its profitability.
The tasks of ISSP UL:
The ISSP researchers will be responsible for the implementation of the following tasks: i) Investigations of raw material impact on efficiency of metal extraction process; ii) Investigations of electrolyte impact on efficiency of metal extraction process; iii) Investigations of technical parameters on efficiency of metal extraction process; iv) Study of metal extraction process reproducibility.
Project progress
Reporting period: 01.09.2023. - 30.11.2023
30.11.2023
The following papers elaborated with the project have been published and submitted:
- E. Rania, P. Talebia, T. Pulkkinena, V. Pankratov and H. Singh, Flexible nanosheets for plasmonic photocatalysis: microwave-assisted organic synthesis of Ni–NiO@Ni2CO3(OH)2 core–shell@sheet hybrid nanostructures, Nanoscale Advances (Published in November 3, 2023) DOI: 10.1039/D3NA00583F
- V. Serga, A. Zarkov, A. Shishkin, M. Melnichuks, V. Pankratov, Regularities of noble (Au, Ag) and base metals leaching from computer PCBs in electrochemical hydrochlorination process using AC, Metals (Accepted for publication in 2023)
- E. Blumbergs, A. Shishkin, K. Markus, V. Serga, D. Goljandin, A. Klauson, V. Abramovskis, J. Baronins, A. Zarkov, V.Pankratov, Economical aspects of the mechanical pre-treatment role in the Precious Metals Recovery from Electronic Waste, Recycling (submitted in October 20, 2023)
- K. Markus, A. Wojewódzka-Wiewiórska, E. Blumbergs, A. Šiško, A. Shishkin, V. Pankratovs, “Sustainable electronic scrap management in regional contexts: a catalyst for innovative business ventures” (submitted in November 30, 2023)
The results have been reported in 9th International Scientific Conference TRENDS IN REGIONAL DEVELOPMENT IN THE EU COUNTRIES 2023, October 20, 2023 (videoconference):
- Kārlis Markus, Agnieszka Wojewódzka-Wiewiórska, Ervīns Blumbergs, Andrejs Šiško, Andrej Shishkin, Vladimirs Pankratovs, Sustainable electronic scrap management in regional contexts: a catalyst for innovative business ventures (poster presentation) https://www.lbtu.lv/sites/default/files/files/notikumi/Programme%20_TRENDS_2023__Conference_0.pdf
Reporting period: 01.06.2023. - 31.08.2023
01.09.2023
Leaching of noble and base metals under AC hydrochlorination process conditions from disintegrator-single and double crushed mixed computer PCBs and disintegrator-double crushed computer motherboards powders with particle sizes (d) < 90 µm, 90–180 µm and 180 –350 µm has been studied. The efficiency of noble and base metals leaching from disintegrator-crushed powders with d ˂ 90 µm into the electrolyte solution (CHCl = 6M) has been established at a solid-to-liquid (S/L) ratio of 2.9 g·L−1, 5.7 g·L−1, 8.6 g·L−1, 11.4 g·L−1 and 14.3 g·L−1.
The influence of HCl concentration (4 M, 6 M and 8 M) as well as the presence of NaCl (1 M and 3 M) in hydrochloric acid electrolyte solutions on the efficiency of metal electrochemical leaching has been studied. To assess the effect of electrolyte temperature on the efficiency of metal leaching, a series of experiments was carried out under the following conditions: temperature control of the electrolyte at 60°C, 70 °C and 80 °C, without forced temperature control and with air and water cooling of the electrolyte.
The impact of electric current superimposition (i=0.63 A·cm–2 and i=0.84 A·cm–2) on the system and current density values (from 0.21 A·cm–2 to 0.84 A·cm–2) at a constant electrolyte temperature (60°C, 70°C and 80°C), the experiment duration and the reuse of the electrolyte in the electrochemical process on the efficiency of metal leaching has been studied.
The research results presented in the reports 3.1, 3.2 and 3.3 are summarized.
To estimate the dispersion of the results of electrochemical leaching of Au, Ag and base metals, a series of repeated experiments under similar conditions were carried out. PCBs powders with a particle size of < 90 μm, obtained as a result of both single and double crushing in a disintegrator, were used as the object of the research. The duration of the experiments in the series ranged from 1 to 6 hours.
Disassembly of computers, removal of printed circuit boards from them, sorting by positions, weighing, crushing in a disintegrator, sorting by fractions. Preparation of the report based on the results of the completed works.
Disintegrator-single and double crushed mixed computer PCBs and disintegrator-double crushed computer mother boards powder fractions with particle sizes < 90 µm, 90-180 µm and 180-350 µm have been obtained. After chemical leaching of metals from the powders under study, the quantitative determination of individual metals in the resulting solutions has been carried out using ICP-OES. Based on the ICP-OES data, a comparative study of chemical composition of above mentioned fractions was carried out.
A comparative analysis of the morphology of the of the raw material powders has been performed based on the obtained optical images.
Compositions of solutions produced at different current densities (0,66 A·cm–2; 0,80 A·cm–2 and 0,88 A·cm-2), raw material particle sizes (< 90 µm, 90-180 µm and 180-350 µm), experiment durations (from 2 h to 6 h), hydrochloric acid concentrations (6 M and 8 M), loading options of the raw material have been studied. Moreover the compositions of the electrolyte reused in the electrochemical leaching, the electrolyte obtained as a result of electrochemical pretreatment of the raw material and subsequent electrochemical leaching have been established.
X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses of the raw material and solid residue samples after both chemical and electrochemical leaching were used for determination of elemental and phase composition, respectively. Disintegrator-single crushed mixed computer PCBs and disintegrator-double crushed computer mother boards powder fractions with a particle size < 90 µm were used as the object of study.
Reporting period: 01.03.2023. - 31.05.2023
01.06.2023
The kinetics of leaching of noble metals and non-ferrous metals in a hydrochloric acid electrolyte solution (CHCl=6M) at an alternating current density i=0.8 A/cm2 from a raw material fraction with d <90 μm and a non-conductive part content of ⁓60% obtained in a disintegrator during the double grinding process was studied. Preparation of the report "Effect of the degree of dispersion of raw materials and the volume ratio of the electrolyte on the extraction process".
The influence of the PCB powder insertion method (in the form of a dispersed phase and in contact with graphite electrodes) on the efficiency of metal leaching from the raw material mass with a particle size of 355-710 µm and a non-conductive fraction content of ⁓ 15 wt% in an electrolyte solution (CHCl=6 M) was investigated. Preparation of the report "The influence of technical parameters on the extraction process".
Prepared liquid samples according to the processes of the model experiments (from activities T3.1; T3.2; T3.3; T3.5) for the quantitative determination of metals in the electrolyte solution by the inductively coupled plasma optical emission spectrometry (ICP-OES) method.
Prepared samples of the solid residue after the processes of the model experiments (from activities T3.1.; T3.2.; T3.3.) for X-ray phase and X-ray fluorescence analysis.
The results of the studies obtained within the project are summarized and presented in the form of a scientific publication: "Study of Metal Leaching from Printed Circuit Boards by Improved Electrochemical Hydrochlorination Technique Using Alternating Current." Serga, V.; Zarkov, A.; Shishkin, A.; Elst, E.; Melnichuk, M.; Maiorov, M.; Blumberg, E.; Pankratov, V. Metals 2023, 13, 662. https://doi.org/10.3390/ met13040662.
Reporting period: 01.12.2022. - 28.02.2023
01.03.2023
The kinetics of leaching of noble metals and non-ferrous metals in a hydrochloric acid electrolyte solution (CHCl=6M) at an alternating current density I=0.6 A/cm2 and I=0 from the starting material fraction with d <90 μm and the content of the non-conducting part ⁓30% (obtained in the disintegrator once in the grinding process) in a thermostated environment at 70 °С.
The influence of alternating current density (in the range from 0.2 to 0.8 A/cm2) on the efficiency of metal leaching from the raw material fraction with d <90 μm and the content of the non-conducting part in ⁓30% electrolyte solution (CHCl=6 M) in a thermostated environment at 60 °С and 70 °С.
Prepared liquid samples according to the processes of the model experiments (from activities T3.1; T3.2; T3.3; T3.5) for the quantitative determination of metals in the electrolyte solution by the inductively coupled plasma optical emission spectrometry (ICP-OES) method.
Prepared samples of the solid residue after the processes of the model experiments (from activities T3.1.; T3.2.; T3.3.) for X-ray phase and X-ray fluorescence analysis.
Based on the obtained results, one publication is in the preparation stage.
Reporting period: 01.09.2022. - 30.11.2022
01.12.2022
Work continued on investigating the effects of PCB dispersion and 'non-metallic' (non-conductive) content. Three powdered fractions with particle size <0.09 mm, 0.09 – 0.18 mm and 0.18 – 0.35 mm with the content of the "non-metallic" part from 5 wt.% to 50 wt.% were used as objects. The transitions of noble metals (Au, Pd), non-ferrous metals (Al, Cu, Pb, Sn, Ni, Ti, Co), as well as Fe, Cr and Mn in an electrolyte solution containing hydrochloric acid in electronic scrap (particle size <0.09 mm) were studied (CHCl= 6M) kinetics at an a.c. density i = 0.88 A/cm2. In the conditions of electrochemical leaching of
metals from electronic scrap, the change of free chlorine concentration in the electrolyte solution was studied.
The influence of the concentration of hydrochloric acid (between 2 and 8 mol/L) in the electrolyte solution on the efficiency of electrochemical leaching of noble and non-ferrous metals from scrap containing ⁓ 5% by weight of non-electrically conductive fractions was studied.
The effect of current density (from 0.6 A/cm2 to 0.9 A/cm2) on the degree of leaching of noble metals and non-ferrous metals from the fraction of raw materials (d< 90 µm) in an electrolyte solution (CHCl= 6M) was studied. The influence of alternating current density on the efficiency of leaching of noble metals and non-ferrous metals from the raw material mass (crushed once in a disintegrator, d <90 μm, non-conductive part ⁓30%), used as a dispersed phase in an electrolyte solution (CHCl=8 M), under thermostatic conditions at 80 °С.
Based on the obtained results, one more manuscripts have been published:
V. Serga, A. Zarkov, E. Blumbergs, A. Shishkin, J. Baronins, E. Elsts, V. Pankratov, Leaching of gold and copper from printed circuit boards under the alternating current action in hydrochloric acid electrolytes, Metals, 12(11) (2022) 1953
Reporting period: 01.06.2022. - 31.08.2022
01.09.2022
Based on the obtained results, two manuscripts have been published:
- P. Talebi, A.A. Kistanov, E. Rani, H. Singh, V. Pankratov, V. Pankratova, G. King, M. Huttula, W. Cao, Unveiling the role of carbonate in nickel-based plasmonic core@shell hybrid nanostructure for photocatalytic water splitting, Applied Energy 322 (2022) 119461
- E. Blumbergs, V. Serga, A. Shishkin, D. Goljandin, A. Shishko, V. Zemcenkovs, K. Markus, J. Baronins, V. Pankratov, Selective Disintegration–Milling to Obtain Metal-Rich Particle Fractions from E-Waste, Metals 12 (2022) 1468
The results have also been presented and discussed at Joint International Conference Functional Materials and Nanotechnologies and Nanotechnology and Innovation in the Baltic Sea Region (FM&NT – NIBS 2022), Riga, Latvia, July 3 – July 6, 2022:
- V. Serga, M. Kuzmins, A. Zarkov, E. Elsts, V. Pankratov, Leaching of valuable metals from scrap printed circuit boards under the action of alternating current, (poster presentation) FM&NT – NIBS 2022, Book of Abstracts p. 244
- E. Blumbergs, A. Shishkin, Application of the disintegration grinding method to increase the efficiency of the processing of used printed circuit boards, (poster presentation) FM&NT – NIBS 2022, Book of Abstracts p. 248
The Latvian patent application has been successfully submitted:
V. Pankratov, E. Blumbergs, V. Serga, A. Zarkov, M. Kuzmins, PAŅĒMIENS METĀLU ELEKTROĶĪMISKAI IZSKALOŠANAI NO ELEKTRONISKAJIEM ATKRITUMIEM MAIŅSTRĀVAS IETEKMĒ SĀLSSKĀBOS ELEKTROLĪTU ŠĶĪDUMOS, Acceptance number: LVP2022000056
Reporting period: 01.03.2022. - 31.05.2022
01.06.2022
Based on the obtained results, materials for publications and participation in conferences were collected. One publication was submitted to the high-ranking journal Applied Energy. A referee report was received from reviewers indicating the need to revise the publication. A new version of the edition has been prepared and submitted. In addition, the conference abstracts were submitted to the FMNT conference, and these conference abstracts were successfully accepted for participation in the conference as poster presentations. A Latvian patent application has been prepared. The patent application has been approved by the ISSP Innovation Department. The patent application has been sent to the FORAL office for further approval.
Reporting period: 01.12.2021. - 28.10.2022
01.03.2022
During the period under review, e-scrap was studied, consisting mainly of printed circuit boards from which liquid samples were prepared by model experimental processes for the quantification of metals. X-ray phase (XRD) and X-ray fluorescence (XRF) analysis was continued, and dry residue characterization by XPS was performed. In addition, photoluminescence measurements of non-metallic nanoparticles in both liquids and solids were performed.
Reporting period: 01.09.2021. - 30.11.2021
01.12.2021
An experimental electrochemical cell with two removable graphite electrodes and an electrolyte volume of 350 ml was prepared. The material is selected and containers are made for placing the test sample. Cell testing experiments using crushed copper foil as raw material were performed. A series of model experiments were performed to investigate the effect of the dispersion of the raw material (PCB) and the content of the “non-metallic” (non-conductive) part. Three powdered fractions with particle sizes <0.09 mm, 0.09 - 0.18 mm and 0.18 - 0.35 mm with a content of “non-metallic” fraction from ⁓5% by weight to ⁓50% by weight were used as objects. Liquid samples were prepared by model experimental processes for the quantitative determination of metals in electrolyte solution by inductively coupled plasma optical emission spectrometry (ICP-OES). Solid residue samples were prepared both after opening the raw material samples and after model experimental processes to perform X-ray phase (XRD) and X-ray fluorescence (XRF) analysis, as well as characterization of the dry residue by XPS method.
Reporting period: 01.06.2021. - 31.08.2021
01.09.2021
Review of the scientific literature on XPS, XRD, microscopy and Raman spectroscopy methods for the characterization of drag and rare earth metals and metal oxides. Experimental design and testing of a laboratory electrolytic cell (V = 500 ml) in model experiments. Preparation of samples for XPS, XRD, Raman spectroscopic measurements from raw scrap materials.