Study On The Process And Mechanism Of Electrolytic Recycling Of Scrap Cemented Carbide By Chlorine Salt

Cemented Carbide is an alloy material comprised of carbides of high hardness refractory metals and bonded metals,produced through a powder metallurgical process.This material boasts high hardness,strength and good wear resistance,earning it the nickname"teeth of industry".With industrial production growing rapidly,so too is the production of cemented carbide scrap.As a result,a large amount of carbide scrap is produced,which if not effectively utilized,will pollute the environment and waste valuable tungsten resources.Therefore,it is of great practical significance to study the recycling of waste carbide.In this study,the molten salt electrolysis method was used to recover valuable metals from waste cemented carbide.The Na Cl-KCl molten salt electrolyte was supplemented with the active substance Na₂WO₄,and YT15 type cemented carbide scrap was used as the anode for electrolytic recovery of tungsten,cobalt and titanium metals.The electrochemical behaviour of tungsten,cobalt and titanium ions in the Na Cl-KCl molten salt system was investigated using electrochemical test methods such as cyclic voltammetry and square wave voltammetry,to study the electrode reaction mechanism of tungsten,titanium and cobalt ions in the Na Cl-KCl and Na Cl-KCl-Na₂WO₄（3%）molten salt systems.Relevant electrochemical parameters were also calculated.The study investigated the effect of electrolysis conditions on the dissolution of cemented carbide scrap.Using a company’s YT15 cemented carbide scrap as the anode and high purity graphite as the cathode in a Na Cl-KCl-Na₂WO₄（3%）molten salt electrolyte at 1023 K,the cathodic electrolysis products were analyzed.The findings were as follows:（1）This study investigated the dissolution of YT15 cemented carbide and its hard phases Ti C,WC,and binder phase Co in the Na Cl-KCl molten salt system at a temperature of 1023 K,and analyzed the electrochemical behavior of the molten salt electrolyte after electrolysis.The results showed that the binder phase Co in the cemented carbide preferentially underwent electrochemical dissolution,and the deposition potentials of Co,W,and Ti ions in Na Cl-KCl molten salt electrolyte were 0.05,-0.28,and-0.81V（vs.Pt）,respectively.（2）The study investigated the electrochemical behaviour of the dissolved Na Cl-KCl molten salt electrolyte containing Ti,W and Co ions.The results showed that the reduction processes of tungsten,cobalt and titanium ions at the tungsten working electrode in the Na Cl-KCl molten salt system were all one-step two-electron transfer reduction processes,and the electrode reactions were subject to diffusion-controlled reversible reactions.At a temperature of 1023 K,the diffusion coefficients of tungsten ions in the Na Cl-KCl molten salt system were 4.136×10^-5 cm²·s^-1,cobalt ions were 9.756×10^-6 cm²·s^-1 and titanium ions were 3.426×10^-5 cm²·s^-1.（3）The study investigated the electrochemical behaviour of tungsten ions in the Na Cl-KCl-Na₂WO₄（3%）molten salt system.The electrochemical reduction of W（VI）in this molten salt system was carried out in two steps,the first step being the reduction process of transferring two electrons and the second step being the reduction process of transferring four electrons,with a diffusion coefficient of 3.426×10^-5 cm²·s^-1.（4）Using YT15 cemented carbide waste as the anode and high-purity graphite as the cathode,the influence of different process parameters such as electrolysis voltage,current,and time on the dissolution behavior of the YT15 cemented carbide waste anode was investigated in the Na Cl-KCl-Na₂WO₄（3%）molten salt system at 1023 K.The effect of electrolysis conditions on the anodic dissolution behavior was studied,and the cathodic electrolysis products were characterized.The results showed that after 6 hours of electrolysis at a voltage of 2.0 V,small particle-shaped W,Co,and Ti metals were obtained on the cathode,with mass fractions of 1.56%,0.27%,and 0.07%,respectively.