A CATHODE ASSEMBLY FOR FEEDING POWDERS INTO PLASMA OF EXPANDED DC ARCS

The cathode assembly is designed for use with the rotating wall, d.c.-arc plasma furnace. Powders are entrained with recirculated gases above the arc root in this device so that the momentum of powder suspensions and magnetofluidmechanical forces can act together to cause powders to penetrate the plasma of expanded d.c. arcs. The powder feed port is encircled by a single tungsten electrode which is shielded to a great extent from chemically reactive gases in the furnace. This assembly has been used to feed many types of powder into the plasma of expanded d.c. arc columns where they may be vaporized. It overcomes almost completely the limitations of the cathode assembly described earlier.