Patent ID: 6143266
Filing Date: 2000-11-07
Classification: C01B,C11D

Abstract:
A method for producing a crystalline inorganic builder having the following composition in its anhydrous form:xM.sub.2 O.ySiO.sub.2.zMeO,wherein x, y and z are numerical values satisfying the following relationships: y/x is 1.0 to 4.0, z/y is not more than 1.0, M stands for Na and K, K/Na is 0.01 to 2.0, and Me stands for Ca and/or Mg, the method comprising the steps of:(a) adding water, a Na-containing compound, a K-containing compound, and at least one member of Ca-containing compounds and Mg-containing compounds to silica sand, to give a mixture;(b) subjecting the resulting mixture to a hydrothermal treatment, wherein said hydrothermal treatment is carried out under the condition of from 5 to 15 kg/cm.sup.2 G, thereby dissolving the silica sand in the mixture; and thereafter(c) baking the resulting treated mixture.