Preparation and Electrochemical Properties of Pb-0.3wt%Ag/Pb-WC Composite Inert Anodes

We prepared Pb-0.3wt%Ag/Pb-WC（WC stands for tungsten carbide,the same below） composite inert anodes by double-pulse electrodeposition on the surface of Pb-0.3wt%Ag substrates,and investigated the electrochemical properties of the composite inert anodes,which were obtained under different forward pulse average current densities from 2 A/dm2 to 5 A/dm2 and WC concentrations from 0 g/L to 40 g/L in bath.The kinetic parameters of oxygen evolution,corrosion potential and corrosion current of the composite inert anodes were obtained in a synthetic zinc electrowinning electrolyte of 50 g/L Zn2＋ and 150 g/L H2SO4 at 35 ℃,by measuring the anodic polarization curves,Tafel polarization curves and cyclic voltammetry curves.The results show that Pb-0.3wt% Ag/Pb-WC composite inert anodes obtained under forward pulse average current density of 3 A/dm2 and WC concentration of 30 g/L in an original acid plating bath,possess higher electrocatalytic activity of oxygen evolution,lower overpotential of oxygen evolution,better reversibility of electrode reaction and corrosion resistance in [ZnSO4＋H2SO4] solution.The overpotential of oxygen evolution of the composite inert anode is 0.926 V under 500 A/m2 in [ZnSO4＋H2SO4] solution,and 245 mV lower than that of Pb-1% Ag alloy;the corrosion current of the composite inert anode is 0.95×10-4A which is distinctly lower than that of Pb-1%Ag alloy,showing the excellent corrosion resistance.

A recyclable method for titanium extraction and oxygen evolution from Ti-bearing slags

Despite its existence for more than 80 years,the titanium industry is still challenged by massive carbon emissions,high production costs,and large resource waste.More than one hundred million tons of Ti-bearing blast furnace slag(TB-slag)has been discarded in China because of the difficulty of reutilization,which requires efficient titanium extraction and recovery technologies.This paper describes a low-cost,carbon-emission-free method for Ti extraction and oxygen evolution via molten oxide electrolysis(MOE)vacuum distillation.After a comprehensive analysis of the binding energies and activities of liquid metals,the highlights of our study are as follows.1)Sb has the best preferential deposition of Ti among a series of high-Ti-affinitive liquid metal cathodes(Cu,Ni,Pb,Sn,and Sb).2)The Ir anode was first used in TB-slag with IrO_(2) formed on its surface to protect it from further corrosion.3)An alloy containing Ti and Ca can be obtained by MOE,and Ti and Ca metals can be refined by further vacuum distillation.4)A closed loop is formed in the overall process owing to the recyclable Sb cathode and continuous feeding of TB-slag into the electrolyte.This simple,low-cost,and environmentally friendly method can realize the efficient utilization of Ti resources and achieve carbon neutrality.