the invention comprises , in one form thereof , a continuous processing apparatus for high temperature thermal treatment of granular materials . the apparatus includes a vertical conveyor means with an internal feed mechanism for transporting granular feedstock upward , an external export means for taking reacted product downward wherein said internal feed heats said granular feedstock by absorbing heat from the product flowing downward through said export means , and a heating means disposed around a top portion of said vertical conveyor means and said external export means .