A rotary tube furnace (1) comprising an insulated heating chamber (4), the insulated heating chamber having a product discharge outlet (21) and a process tube inlet (39), a heating element (14) operatively arranged to selectively heat the heating chamber, a generally horizontally extending process tube (2) supported for rotation relative to the heating chamber, the process tube having a first portion (36) generally arranged outside of the heating chamber and a cantilevered second portion (37) extending from the first portion into the heating chamber and terminating at a discharge end (38) within the heating chamber, a feed mechanism (40) configured and arranged to feed product into the process tube, and a bearing assembly operating between a support frame (34) and the first portion of the process tube and configured and arranged to support the process tube and transmit rotational torque to the process tube.