Amorphous sodium silicate-metal sulfate composite powder

Abstract

Amorphous sodium silicate-metal sulfate composite powder having water softening power and having small hygroscopicity, and useful as a detergent builder is provided. This amorphous sodium silicate-metal sulfate composite powder is characterized in that it contains a metal sulfate, for example, sodium sulfate, as solid solution, and when the SiO.sub.2 /Na.sub.2 O molar ratio is expressed by n and the specific surface area thereof is expressed by S (m.sup.2 /g), n and S satisfy the following expressions: 1.60.ltoreq.n.ltoreq.2.80 0.10.ltoreq.S.ltoreq.2.00 , provided that it is assumed that the molar number of Na.sub.2 O is the molar number of Na.sub.2 O based on sodium silicate, and does not contain the molar number of Na.sub.2 O based on sodium sulfate in the case where the metal sulfate is sodium sulfate. This powder is prepared by grinding sodium silicate cullet containing the metal sulfate as solid solution.

Dependencies are inferred from the claim text.