Source : Webster's Revised Unabridged Dictionary (1913)

Limekiln \Lime"kiln`\ (l[imac]m"k[i^]ln`), n.
   A kiln or furnace in which limestone or shells are burned and
   reduced to lime.

Source : WordNet®

limekiln
     n : a kiln used to reduce naturally occuring forms of calcium
         carbonate to lime