Challenge to novel copper electrolysis process of super power saving type using resources circulation type recycling materials

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18829
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Kyushu University
• Principal Investigator: Nakano Hiroaki 九州大学, 工学研究院, 教授 (70325504)
• Co-Investigator(Kenkyū-buntansha): 谷ノ内 勇樹 九州大学, 工学研究院, 准教授 (40644521) ; 大上 悟 九州大学, 工学研究院, 助教 (90264085)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 不動態 / スライム / 銅 / アノード / 電解 / 不純物 / 添加剤 / 拡散係数

Outline of Final Research Achievements

The effect of impurities and additives in solution on the passivation of Cu anode with purity of 78.7 mass% was clarified. The passivation was significantly easy to occur with an addition of 0.596 mol・dm-3 of Ni2+ ions, and was easy to occur with the addition of As5+ and Bi3+ ions. With an addition of Ni2+ ions, the viscosity of solution increased and the diffusion coefficient of Cu2+ ions decreased. As5+ and Bi3+ ions formed the compounds of As-Sb-O and As-Bi-O system in the slime, resulting in increase in compactness of slime. The passivation was significantly promoted with an addition of Cl- ions above 1.13 mmol・dm-3. Cl- ions formed the CuCl at the upper area of slime and increased the compactness of slime, resulting in promotion of passivation.

Free Research Field

材料電気化学

Academic Significance and Societal Importance of the Research Achievements

電力コストを低減させる観点から，低品位な粗Cuについても電解精製の適応が望まれている。アノードに低品位Cuを用いる電解精製を実現するためには，アノードの不動態化と電解条件の関係を把握することが必須である。その一環として，低品位Cuアノードの不動態化に及ぼす電解液中の不純物イオン，添加剤の影響を明らかにすることができた。また，電解装置を自作して，アノード，カソードの電解液の流れおよび不動態化時のCuSO4膜の形成挙動の可視化に成功した。