To provide a method for obtaining impurity-free high-whiteness calcium carbonate usable as a filler for paper making or a pigment for coated paper from lime sludge produced when green liquor obtained in a kraft process pulp manufacturing process is causticized by adding unslaked lime or slaked liquor obtained by reacting unslaked lime with sodium hydroxide-containing liquor.

In the method for producing calcium carbonate from the lime sludge produced by causticizing green liquor obtained in a kraft process pulp manufacturing process with unslaked lime or slaked liquor obtained by reacting unslaked lime with sodium hydroxide-containing liquor, the lime sludge is dried by passing through a cyclone using high-temperature hot air after a white liquor recovering step so that high-whiteness lime sludge freed of impurities is obtained. It is preferable that the high-temperature hot air used in the cyclone utilizes the exhaust heat of the kiln.