text: A rotary kiln is a pyroprocessing device used to raise materials to a high temperature (calcination) in a continuous process.  Materials produced using rotary kilns include:
  * Cement
  * Lime
  * Refractories
  * Metakaolin
  * Titanium dioxide
  * Alumina
  * Vermiculite
  * Iron ore pellets
  They are also used for roasting a wide variety of sulfide ores prior to metal extraction.