Method for the production of precipitated calcium carbonate with a high degree of brightness

摘要

Calcium carbonate with high brightness is prepared by treating calcium carbonate and/or the milk of lime used for its preparation by reacting milk of lime with carbon dioxide and/or at least one of the calcium-containing preliminary products used for the preparation of the milk of lime before, during and/or after this reaction with a bleaching agent which comprises at least one compound of the formula (I): A[(CR¹R²)SO_pM_(1/q)]_r (I) where the variables have the following meanings: A is NR³R⁴, NR³, N or OH; R¹, R², R³, R⁴ independently of one another, are hydrogen or an organic radical; M is ammonium or metal p is 2 or 3; q is the valency of M; and r is 1 when A = OH or NR³R⁴, is 2 when A = NR³ and is 3 when A = N; and where variables, if a mixture of compounds is used and/or r=2 or 3, are chosen independently of one another for each individual compound and/or for each [(CR¹R²)SO_pM_(1/q)] group.