PRODUCTION OF LIGHT CALCIUM CARBONATE

摘要

PURPOSE:To produce the light calcium carbonate having a Hunter whiteness degree of 91-98% by using calcined lime produced with a lime sludge kiln as a raw material. CONSTITUTION:The method for producing light calcium carbonate having a Hunter whiteness degree (JIS P 8123) of 91-98% comprises mixing calcined lime produced with a lime sludge kiln by an alkaline pulp-digesting method with water; reacting the mixture with carbon dioxide; and subsequently bleaching the produced calcium carbonate with a reductive bleaching agent. The method permits to provide light calcium carbonate having a Hunter whiteness degree usable as a paper filler and capable of eliminating impurity-containing calcium carbonate which has been an industrial waste in alkaline pulp digesting method.