Open AccessRecycling of Gold Using Anodic Electrochemical Deposition from Molten Salt Electrolyte
Author(s) -
Takanari Ouchi,
Shuang Wu,
Toru H. Okabe
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/aba6c5
Subject(s) - molten salt , oxidizing agent , anode , scrap , dissolution , electrolyte , electrochemistry , deposition (geology) , hazardous waste , salt (chemistry) , cathode , materials science , chemistry , inorganic chemistry , metallurgy , waste management , electrode , paleontology , organic chemistry , sediment , engineering , biology
Recycling of precious metals is becoming increasingly important as our living standards improve and electronic technologies advance. Conventional recycling processes involve multi-step hydrometallurgical treatments, in which precious metals are dissolved in aqueous solutions using a combination of strong complexing agents and oxidizing agents. However, these processes are time consuming and produce a large amount of hazardous liquid waste. Here, we present a new recycling process for Au, which is based on the direct anodic electrochemical deposition of anionic Au ions dissolved in a molten salt electrolyte. Moreover, this process is simple and does not generate harmful waste. In this process, Au is alloyed with Na to facilitate its dissolution in a molten mixture of NaCl–NaI. The existence of Au as an anionic species (Au n − ) in the molten salt was proven and its anodic deposition (oxidation reaction) by application of an anodic current was demonstrated. During the anodic deposition of Au, Na is deposited on the cathode and can be recovered and reused in the process. It is expected that this electrodeposition technique to recycle Au from scrap metal could result in the development of a new environmentally friendly Au recycling process that does not generate hazardous waste.