Patent ID: 9650298
Date: 2017-05-16
CPC Classifications: C04B

Claim:
1. Process for the preparation of a hardening accelerator composition, containing calcium silicate hydrate, by reaction of a water-soluble calcium compound, optionally calcium salt, with a water-soluble silicate compound, the reaction of the water-soluble calcium compound with the water-soluble silicate compound being carried out in the presence of an aqueous solution which contains a plasticizer for hydraulic binders, selected from the group of (A) comb polymers, (B) polycondensates containing (I) at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing a polyether side chain and (II) at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing at least one phosphoric acid ester group, (C) lignosulphonates and/or (D) β-naphthalene sulphonate formaldehyde condensates (BNS), characterized in that the reaction of the water-soluble calcium compound with the water-soluble silicate compound is being carried out in the presence of apatite and that the molar ratio of calcium to phosphorus in the hardening accelerator is from 25/1 to 400/1.