The limestone of Swabi district was used to produce precipitated calcium carbonate. The optimum calcination temperature and time was found to be 1000°C-1100°C and 3 hours to 4 hours respectively. The results show that the stirrer speed of 130 rpm is the most suitable, as higher speed causes attrition of precipitates. The required particle size of precipitates of calcium carbonate can be achieved by choosing the right concentration of calcium hydroxide suspension. The impurities provide additional nucleus for precipitate formation affecting brightness and specific gravity of the product.
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