Vertical Shaft Kilns HarbisonWalker International
Vertical Shaft Kilns. Lime shaft kilns are stationary vertical kilns where the raw limestone enters at the top and gravity flows through three thermally zoned sections known as the preheating, calcining, and cooling zones. The process heats the limestone from ambient temperature to 900#176;C, which is the point where the carbon dioxide is driven off, leaving calcium oxide, also known as quicklime.