Calcination of Limestone May02

Calcination of Limestone...

Calcination of Limestone Calcination or calcining is a thermal treatment process to bring about a thermal decomposition. The process takes place below the melting point of the product. The name calcination is derived from the Latin word ‘Calcinare’ which mean to burn lime. Limestone is a naturally occurring mineral. It exists nearly all over the world. The chemical composition of this mineral varies greatly from region to region as well as between different deposits in the same region. Therefore, the end product from each natural deposit is different.  Typically limestone is composed of calcium carbonate (CaCO3), magnesium carbonate (MgCO3), silica (SiO2), alumina (Al2O3), iron (Fe), sulphur (S) and other trace elements. Limestone is one of the most basic raw materials employed in the steel industry and is used both in iron making and steel making processes. Lime (CaO) is one of the oldest chemicals known to man and the process of lime production is one of the oldest chemical industries. Quicklime was produced in US as early as 1635 in Rhode Island. Technical progress which was non existing in centuries past, has rapidly advanced the lime industry during the last fifty years in the area of process methods and design. Limestone deposits are wide distributed. The limestone from the various deposits differs in physical chemical properties and can be classified according to their chemical composition, texture and geological formation. Limestone is generally classified into the following types: High calcium – The carbonate content is composed mainly of calcium carbonate with a magnesium carbonate content not more than 5 % (usually less).  Magnesium – This contains magnesium carbonate to about 5 – 20%. Dolomitic -This is also known as dolomite and contains over 20 % of MgCO3. However the maximum MgCO3 content does not exceed...