Precipitated Calcium Carbonate Manufacturing Process
Precipitated calcium carbonate is produced using the most economic process existing today. Limestone is converted into calcium oxide and carbon dioxide by means of calcination at temperatures in excess of 900°C. To ensure a high level of purity, the calcination process is carried out using natural gas. After the calcined lime has been slaked with water, the resulting milk of lime is purified and carbonated with the carbon dioxide obtained from the calcination process (See reactions below).
The process flow diagram shows precipitated calcium carbonate (PCC) production from limestone[/caption] Calcination. Initially, the limestone from a quarry is stored in bins. Typical extracted limestone contains about 75 wt.% of CaCO3. Mined limestone is crushed in a jaw crusher and calcined (burned) in a vertical-shaft lime kiln at about 1,000°C.