Internal baffles are plates or other barrier structures positioned inside a furnace tube to promote uniform mixing of the material being processed and to break up any clumps that may form. By disrupting the material flow, baffles increase contact between particles and the heated surface, which improves heat transfer and processing consistency. This feature is especially useful for powders or granular materials that tend to settle, stick, or agglomerate during thermal treatment in rotary or tube furnaces.