1 This International Standard specifies the methods to be used for the evaluation of natural calcium carbonate (chalk or limestone) ground to a dry powder for use in the rubber industry.
NOTE 1 Classification of natural calcium carbonate according to fineness and chemical purity and typical physical and
chemical properties for use in the rubber industry are given in informative annex D.
NOTE 2 This International Standard does not cover calcium carbonates prepared by precipitation from solution.
2 There are two sets of analytical methods listed in this International Standard. In the body of the text (4.8.2 to 4.8.4), the traditional spectrophotometric methods are given; these are obsolescent, time-consuming and use a chlorinated solvent. It is recommended that these methods be phased out and replaced by the atomic absorption methods listed in annexes A, B and C.