甲基磺酸体系粗铅电解精炼的电沉积行为与概念验证运行

Electro-deposition behavior and proof-of-concept operation in methanesulfonic acid-based crude lead electro-refining

提出一种替代传统氟硅酸体系的甲基磺酸(MSA)体系,它具有挥发性低、腐蚀性低、热稳定性良好和导电性高的优点,能够实现绿色高效铅电解精炼。探讨基于MSA体系的粗铅电精炼(MPR)电沉积行为,包括其运行机理、反应可逆性、形核和生长模式。基于循环伏安法(CV)和计时电流法(CA),揭示受扩散控制且不可逆的MPR铅沉积过程,建立MPR铅沉积形核和生长的瞬态成核理论模型。MPR小规模验证性运行实现了104.22 kW·h/t Pb的能耗和99.24%的电流效率,相较于H_(2)SiF_(6)体系的120 kW·h/t Pb能耗与95%电流效率,具有竞争性。MPR小规模运行获得了纯度99.9925%且光滑致密的铅沉积层,满足铅锭纯度99.97%的标准(GB/T 469—2013)。

A promising methanesulfonic acid(MSA)system,in lieu of conventional fluosilicic acid system,for green and efficient electro-refining of Pb,was proposed,due to its low volatility,low corrosivity,desired thermal stability and high conductivity.The electro-deposition behavior of the MSA-based Pb electro-refining(MPR)was explored,including its operation mechanism,reaction reversibility,nucleation,and growth mode.Based on cyclic voltammetry(CV)and chronoamperometry(CA),the diffusion-controlled and irreversible lead deposition process of MPR was revealed,and the theoretical model of MPR lead deposition nucleation and growth with transient nucleation was established.The bench-scale proof-of-concept operation of MPR achieved energy consumption of 104.22 kW·h/t Pb and current efficiency of 99.24%,which was competitive with the energy consumption of 120 kW·h/t Pb and current efficiency of 95%for H_(2)SiF_(6)system.The bench-scale operation of MPR obtained a smooth and compact deposit sample with Pb purity of 99.9925%,which satisfied the standard of Pb ingot(GB/T 469-2013)of 99.97%.