SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2019, Vol. 27 ›› Issue (5): 1191-1199.DOI: 10.1016/j.cjche.2018.09.005

• Energy, Resources and Environmental Technology • 上一篇    下一篇

An energy saving and fluorine-free electrorefining process for ultrahigh purity lead refining

Xuan Zhang, Junqing Pan, Yanzhi Sun, Yongjun Feng, Huixia Niu   

  1. State Key Laboratory of Chemical Resource Engineering, Beijing Engineering Center for Hierarchical Catalysts, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
  • 收稿日期:2018-06-27 修回日期:2018-08-28 出版日期:2019-05-28 发布日期:2019-06-27
  • 通讯作者: Junqing Pan
  • 基金资助:
    Supported by the National Natural Science Foundation of China (21676022) and the Fundamental Research Funds for the Central Universities (BHYC170A & JD701).

An energy saving and fluorine-free electrorefining process for ultrahigh purity lead refining

Xuan Zhang, Junqing Pan, Yanzhi Sun, Yongjun Feng, Huixia Niu   

  1. State Key Laboratory of Chemical Resource Engineering, Beijing Engineering Center for Hierarchical Catalysts, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
  • Received:2018-06-27 Revised:2018-08-28 Online:2019-05-28 Published:2019-06-27
  • Contact: Junqing Pan
  • Supported by:
    Supported by the National Natural Science Foundation of China (21676022) and the Fundamental Research Funds for the Central Universities (BHYC170A & JD701).

摘要: The present paper reports a new fluoride-free and energy-saving lead electrolytic refining process in order to solve the serious problems of the existing Betts lead electrorefining process, such as low production efficiency, high energy consumption and fluorine pollution. In the process, a mixed solution of perchloric acid and lead perchlorate (HClO4-Pb(ClO4)2) with the additives of gelatin and sodium lignin sulfonate is employed as the new electrolyte. The cathodic polarization curves show that HClO4 is very stable, and there is no any reduction reaction of HClO4 during the electrolytic process. The redox reactions of lead ions in HClO4 solution are very reversible with an ultrahigh capacity efficiency, so the HClO4 acts as a stable support electrolyte with higher ionic conductivity than the traditional H2SiF6 electrolyte. The results of the scale-up experiments show that under the optimal conditions of 2.8 mol·L-1 HClO4, 0.4 mol·L-1 Pb(ClO4)2 and electrolysis temperature of 45℃, the energy consumption is as low as 24.5 kW·h·(t Pb)-1, only about 20% of that by Betts method at the same current density of 20 mA·cm-2, and the purity of the refined lead is up to 99.9992%, much higher than that specified by Chinese national standard (99.994%, GB/T 469-2013) and European standard (99.99%, EN 12659-1999).

关键词: Lead refining, Perchloric acid, Fluoride-free, Electrorefining process

Abstract: The present paper reports a new fluoride-free and energy-saving lead electrolytic refining process in order to solve the serious problems of the existing Betts lead electrorefining process, such as low production efficiency, high energy consumption and fluorine pollution. In the process, a mixed solution of perchloric acid and lead perchlorate (HClO4-Pb(ClO4)2) with the additives of gelatin and sodium lignin sulfonate is employed as the new electrolyte. The cathodic polarization curves show that HClO4 is very stable, and there is no any reduction reaction of HClO4 during the electrolytic process. The redox reactions of lead ions in HClO4 solution are very reversible with an ultrahigh capacity efficiency, so the HClO4 acts as a stable support electrolyte with higher ionic conductivity than the traditional H2SiF6 electrolyte. The results of the scale-up experiments show that under the optimal conditions of 2.8 mol·L-1 HClO4, 0.4 mol·L-1 Pb(ClO4)2 and electrolysis temperature of 45℃, the energy consumption is as low as 24.5 kW·h·(t Pb)-1, only about 20% of that by Betts method at the same current density of 20 mA·cm-2, and the purity of the refined lead is up to 99.9992%, much higher than that specified by Chinese national standard (99.994%, GB/T 469-2013) and European standard (99.99%, EN 12659-1999).

Key words: Lead refining, Perchloric acid, Fluoride-free, Electrorefining process