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[(CR.sup.1R.sup.2)SO.sub.pM.sub.(1/q)].sub.r (I) where the variables
have the following meanings:
TABLE-US-00001
A is NR.sup.3R.sup.4, NR.sup.3, N or OH;
R.sup.1, R.sup.2, R.sup.3, R.sup.4 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 NR.sup.3R.sup.4, is 2 when A = NR.sup.3
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 [(CR.sup.1R.sup.2)SO.sub.pM.sub.(1/q)] group.