|Calcination Process||CaCO3||CaO + CO2|
|Slaking of Quicklime||CaO + H2O||Ca(OH)2|
|Carbonation||Ca(OH)2 + CO2||CaCO3 + H2O|
Limestone is converted into calcium oxide and carbon dioxide by means of calcinations at temperatures in excess of 900°C. To ensure a high level of purity, the calcinations process is carried out using natural gas.
The temperature, flow of Natural Gas and Fresh Air has to be controlled properly to ensure the high quality Calcium Oxide. Unless the calcinations process is done properly, the quality of the product can not be maintained. The first and the Foremost important process of manufacturing Calcium Carbonate is Calcinations.
The Calcium Oxide (Calcined Lime) derived through the Calcinations process is then slacked with water to obtain Calcium Hydroxide (Milk of Lime). The resultant slurry contains some impurities and to remove the impurities it is passed through a wire mesh which removes some un burnt or over burnt lime hence a better quality is ensured.
The purified milk of lime is then carbonated with Carbon Dioxide which is derived during the first process of Calcinations. This process ensures the Calcium Carbonate and water. Proper temperature and concentration has to be maintained during this process to ensure desired product. The resultant mixture of calcium carbonate and water is again passed through the wire mess to remove any impurity if still left.
The drying is a physical process and no chemical changes to the material are made at this stage. The final stage of the process is water solid separation; water is to be removed from calcium carbonate. this process is completed in two stages viz. making cake by use of centrifuge which contains around 30% moisture. The cake then is dried through a spindle dryer where the material travels with hot air at a temperature of more than 300o C.
The material is then packed in HDPE bags at the outlet. The material is packed in inner laminated HDPE bags to ensure no further quality problems to the material.