Introduction

Dolomitic quicklime is the name given to the quicklime formed from calcining a natural dolomitic limestone that contains nearly an equal molar weight percentage of calcium oxide to magnesium oxide. Ideally, this quicklime would contain 56% calcium oxide, 40% magnesium oxide, and 4% other major lime impurities such as iron oxide, aluminum oxide, silicon dioxide, and sulfur.






Process
The production of high calcium quicklime (magnesium oxide) requires a large amount of heat, which is generated in the kiln environment. The quarried and sized high magnesium limestone travels through a rotary kiln and is subjected to these high temperatures where the calcium carbonate begins to dissociate with the resultant formation of magnesium oxide. The minimum temperature for the dissociation of calcium carbonate is 1648oF (898oC). For practical production purposes, however, the kiln temperature range is from an initial temperture of about 1750oF (954oC) to a final temperature of about 1950oF (1066oC). These temperatures can vary dependent upon the nature of the limestone being calcined.

"Dolomitic" Limestone Calcination: