Preparation and characterization of tungsten nanopowders from WC scrap in molten salts

• A novel process to prepare tungsten via electrolysis of WC scrap was proposed.
• The tungsten component in the WC anode was dissolved as W(II).
• The cathode reaction was controlled by the diffusion of tungsten ions.
• Pure tungsten nanopowders were obtained on the cathode.

Tungsten carbide (WC) scrap was used as a consumable anode to prepare tungsten powder in NaCl–KCl melt at 1023 K for the first time. The electrolysis process was investigated. Results showed that the tungsten component in WC anode was dissolved as W2 + into the NaCl–KCl melt. The cathode reaction was controlled by the diffusion of tungsten ions. The effect of electrolysis parameters, including the anode–cathode distance, cathode current density and different electrolysis ways (galvanostatic and potentiostatic electrolysis), on the purity and grain size of the cathode deposits was studied. It showed that a large anode–cathode distance was beneficial to the formation of pure tungsten powder at the cathode. With increasing the cathode current density, the tungsten grain size first decreased and then increased. When the cathode current density was 0.125 A cm− 2, tungsten powder with a diameter of smaller than 100 nm was obtained. Deposits prepared through galvanostatic and potentiostatic electrolysis was compared in the end.

Tungsten carbide (WC) scrap was used as a consumable anode to prepare tungsten powders in NaCl–KCl melt at 1023 K. WC was electrochemically dissolved as W2+ to supply tungsten ions, which were then discharged on the cathode and deposited as elemental tungsten. Tungsten powder with a diameter of smaller than 100 nm was obtained through the optimization of electrolysis parameters.Figure optionsDownload as PowerPoint slide