Environmentally Sound Recovery of Gold from Waste Electrical and Electronic Equipment Using Organic Aqua Regia
Akihiro Yoshimura, Kota Takatori, and Yasunari Matsuno
Graduate School of Engineering, Chiba University
1-33 Yayoi-cho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan
We conducted experiments using unit processes to prove the feasibility of the concept of an environmentally sound Au recovery process from waste electrical and electronic equipment (WEEE) using organic aqua regia, i.e., a propylene carbonate (PC) solution containing CuBr2 and KBr. First, the WEEE samples (memory card and mobile phone board) were finely ground. The samples were then carbonized and oxidized to decompose the polymers and oxidize the base metals. The leaching of Au from the oxidized samples was then carried out in a PC solution with 0.2 M of CuBr2 and 0.2 M of KBr over 353–373 K, followed by biphasic separation with sulfuric acid. The dissolved Au in the PC phase was recovered via ascorbic acid reduction. The mass balance of Au in the leaching was investigated. The maximum recovery ratios of Au from the memory card and mobile phone board were 79% and 83%, respectively. The cost of leaching was preliminarily estimated.
-  K. Whalen and D. Peck, “In the Loop- Sustainable, Circular Product Design and Critical Materials,” Int. J. Automation Technol., Vol.8, pp. 664-676, 2014.
-  B. Owens, “Mining: Extreme prospects,” Nature, Vol.495, S4-S6, 2013.
-  S. Syed, “Recovery of gold from secondary sources – A review,” Hydrometallurgy, Vols.115-116, pp. 30-51, 2013.
-  J. Cui and L. Zhang, “Metallurgical recovery of metals from electronic waste: a review,” J. Hazard. Mater., Vol.158, pp. 228-256, 2008.
-  J. P. Young and J. F. Derek, “Recovery of high purity precious metals from printed circuit boards,” J. Hazard. Mater., Vol.164, pp. 1152-1158, 2009.
-  T. Okabe, “Current Status of Platinum Group Metals and Recycling Technologies,” Materia Japan, Vol.46, pp. 522-529, 2007.
-  J. Shibata and A. Okuda, “Recycling Technology of Precious Metals,” Shigen-to-Sozai, Vol.118, pp. 1-8, 2002.
-  M. Matsumoto, N. Mishima, and S. Kondoh, “Tele-Inverse Manufacturing – An International E-Waste Recycling Proposal,” Int. J. Automation Technol., Vol.3, pp. 11-18, 2009.
-  Y. Kishita, E. Kunii, S. Fukushige, Y. Umeda, and J. Fujimoto, “Scenario Analysis of Global Resource Circulation with Traceability Index Targeting Sustainable Manufacturing,” Int. J. Automation Technol., Vol.3, pp. 3-10, 2009.
-  A. Yoshimura, M. Takai, and Y. Matsuno, “Novel process for recycling gold from secondary sources: Leaching of gold by dimethyl sulfoxide solutions containing copper bromide and precipitation with water,” Hydrometallurgy, Vol.149, pp. 177-182, 2014.
-  A. Yoshimura, K. Umehara, M. Takai, and Y. Matsuno, “Development of Recycling System of Precious Metals and Rare Metals Using DMSO Solvent Containing CuBr2,” J. Japan Inst. Mat. Mater., Vol.79, pp. 41-48, 2015.
-  K. Umehara and Y. Matsuno, “Fundamental Studies on a Recycling System for Precious and Rare Metals Using a Propylene Carbonate Solvent Containing CuBr2 and KBr,” Materials Trans., Vol.56, pp. 1579-1584, 2015.
-  Y. Matsuno and M. Takai, “Precious metal recovery method using copper halide-containing organic solvent system,” Japan Patent 6196662, 2017.
-  M. Chaudhry and I. Persson, “Transfer thermodynamic study on the copper(II) ion from water to methanol, acetonitrile, dimethyl sulfoxide and pyridine,” J. Chem. Soc., Faraday Trans., Vol.90, pp. 2243-2248, 1994.
-  K. Izutsu, “Electrochemistry in Nonaqueous Solutions,” Wiley-VCH., pp. 35-37, 2009.
-  A. Yoshimura and Y. Matsuno, “A novel process for the production of gold micrometer-sized particles from secondary sources,” Materials Trans., Vol.57, pp. 357-361, 2016.
-  T. Komenami, M. Sato, C. Sato, and Y. Matsuno, “Development of a Production Method for Palladium Micrometer-Sized Particles Using DMSO Solvent Containing CuCl2,” J. Japan Inst. Met. Mater., Vol.82, pp. 461-466, 2018.
-  K. Takatori, T. Mineo, Y. Nagase, R. Nagoya, K. Sakurai, H. Sasaki, K. Otabe, and Y. Matsuno, “Development of Recycling System of Gold from Secondary Resources Using Organic Aqua Regius,” J. Japan Inst. Met. Mater., Vol.82, pp. 467-475, 2018.
-  T. Yumoto and T. Shiratori, “Study on Recycling of Metals in WEEE – Investigation for making an inventory of metal components –,” J. MMIJ., Vol.125, pp. 75-80, 2009.
-  K. Takahashi, J. Nakamura, K. Otabe, M. Tsuruoka, Y. Matsuno, and Y. Adachi, “Resource Recovery from Mobile Phone and the Economic and Environmental Impact,” J. Japan Inst. Metals., Vol.73, pp. 747-751, 2009.
-  J. Mizuguchi, S. Suzuki, M. Kaneko, and H. Sakahashi, “Recent Advances in TASC (Thermal Activation of Semi-Conductors) Technology for Environmental Issues Focused on the Disassembly and Recycling of Solar Panels and Laminated Glass – A New Technology Characterized by Radical Propagation in Giant Molecules –,” Mater. Trans., Vol.56, pp. 1615-1625, 2015.