High temperature rotating vacuum kiln and method for heat treating solid particulate material under a vacuum

The present invention relates to a rotary vacuum kiln for the treatment of solid particulate material under conditions of high temperature and under a high vacuum. A rotating vacuum kiln for heat treating solid particulate material under vacuum conditions uses a rotating refractory metal cylindrical vessel with a cool inlet zone, hot intermediate zone, and cool exit zone, with a first series of inner radiation shields provided at the hot intermediate zone adjacent to the cool inlet zone and a second series of inner radiation shields provided at the hot intermediate zone adjacent the cool exit zone to protect those two zones from the high temperatures in the hot intermediate zone. Heat for the hot intermediate zone of the cylindrical vessel is provided indirectly by electrical resistance heaters that surround the vessel and outer radiation shields are provided about the heaters to direct heat to the cylindrical vessel.