| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high purity hydrotalcite compound having powder properties suitable as an additive for a synthetic resin and a filler by subjecting an aqueous solution of water-soluble aluminum compound and an aqueous solution of a water-soluble magnesium compound and/or a water-soluble zinc compound to coprecipitation reaction and hydrothermal one and then by pH control. SOLUTION: The objective hydrotalcite compound is expressed by formula I [wherein, M2+ is Mg2+ or Zn2+; 0.2<=(x)<0.5; A2+ is CO32+ or SO42+; (m) is 0-2], has <=100 ppb uranium content, <=3μm average secondary particle diameter and <=30 m2/g and is subjected to surface treatment with a silane-based coupling agent or the like. The rejection ratio of uranium is improved by the coprecipitation reaction of an aqueous solution of a chloride, a nitrate, a sulfate or the like of Al, Mg and/or Zn under a basic condition at 10-50 deg.C while meeting the molar ratio range of raw material composition, expressed by formula II (wherein, M2 is Mg or Zn) and by subjecting the reaction product suspension to hydrothermal reaction at 90-200 deg.C for >=0.5 h and adjusting the suspension product so as to show pH 7.0-13.5. |
