Electrochemical production of microdispersed tungsten oxide powder from technogenic waste of metallic tungsten under the influence of alternating current in ammonia carbonate solutions

A comparative analysis of the processes of electrochemical oxidation of metallic tungsten in ammonium carbonate solutions under the action of direct and sinusoidal alternating current of industrial frequency (50 Hz) was carried out with a change in current density (0.3 - 2.0 A/cm2), temperature (20 - 50 °C) and concentration of ammonium carbonate (0.5 - 1.0 M) in the electrolyte. It was revealed that the maximum oxidation rate of metallic tungsten under the action of alternating current, corresponding to its complete transition into solution, is ~960 mg/cm2 -h, but is two times lower than that when using direct current. It was found that the use of alternating current allows for the electrochemical oxidation of tungsten with the formation of a microdispersed powder based on tungsten (IV) oxide. A basic technological scheme of the process of electrochemical processing of metallic tungsten waste under the action of alternating current has been proposed and tested, allowing the production of tungsten oxide powder (with a tungsten extraction rate of ~42%) along with ammonium paratungstate.