Controllable Production of Ag/Zn and Ag Particles from Hydrometallurgical Zinc Solutions

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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ACS Sustainable Chemistry and Engineering, Volume 9, issue 24
Ag/Zn and Ag particles have been successfully produced from electrolytes simulating zinc process solutions containing a high zinc concentration (65 g/L) and a negligible silver concentration (0.5-50 ppm) using a facile and sustainable electrodeposition-redox replacement (EDRR) method. Results show that the particle size and chemical composition of the deposited Ag/Zn and Ag particles can be readily controlled by varying the operating parameters such as replacement time and agitation. Electrochemical quartz crystal microbalance (EQCM) studies supported with SEM-EDS and TEM results indicate that the EDRR process consists of three regions: (I) zinc pulse deposition; (II) redox replacement between the Ag+ ions and the deposited Zn, formation of a Zn/Ag alloy structure, and competing Zn oxidation by H+ ions; and (III) further replacement between Ag+ ions and Zn (alloy) formed in the previous stage and possible silver reduction by hydrogen. The Zn (alloy) has a higher reduction potential which hinders the competingH+ reduction and sequentially improves the utilization efficiency of the sacrificial metal (Zn). Furthermore, by using the EDRR method, Ag/Zn particles could be successfully obtained from solutions with an extremely low Ag concentration of 0.5 ppm. The promising results demonstrate the feasibility of producing Ag-based functional materials utilizing trace amounts of Ag from zinc process solutions.
Funding Information: Academy of Finland projects (GoldTail (319691) and NoWASTE (297962)) are greatly acknowledged for funding this research. The RawMatTERS Finland Infrastructure (RAMI) funded by the Academy of Finland and based at Aalto University is also acknowledged. In addition, the financial support from the Chinese Scholarship Council (CSC) is gratefully acknowledged by Z.W. S.D. was supported by the Ella and Georg Ehrnrooth Foundation. J.V. acknowledges with gratitude the funding from the Academy of Finland (SUPER-WEAR: Decision number: 322214 and SUBSTAINABLE: Decision number: 334818). Publisher Copyright: © 2021 American Chemical Society. All rights reserved.
Bimetallic particles, Circular economy, Electrodeposition, Precious metal, Redox replacement
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Wang , Z , Hannula , P-M , De , S , Wilson , B P , Vapaavuori , J , Yliniemi , K & Lundström , M 2021 , ' Controllable Production of Ag/Zn and Ag Particles from Hydrometallurgical Zinc Solutions ' , ACS Sustainable Chemistry and Engineering , vol. 9 , no. 24 , pp. 8186–8197 .