PURPOSE: To manufacture basic aluminum slufate having a radial shape by adding a soluble sulfate to a soln. of a basic aluminum salt represented by a specified formula under specified conditions.
CONSTITUTION: A soluble sulfate is added to a soln. of a basic aluminum salt represented by a formula Al(OH)cXd (where X is a univalent anion, c+d=3 and 1.89≤c≤2.55) at an addition rate at which addition time T required to make the molar ratio of SO4/Al (3-c)/2 satisfies 0≤T<1.50 and one of equations T≥ -14c+28 and c>1.90 to obtain radial basic aluminum sulfate represented by a formula Al(OH)a(SO4)b.2H2O (where a+2b=3, 2.34≤a≤2.50, 0.25≤b≤0.33 and 0≤n≤10). The basic aluminum salt soln. is prepared by adding an alkali soln. to a soln. of an aluminum salt of a univalent anion by an amount required to adjust the molar ratio of OH/Al in the soln. to 1.89W2.55, and the soluble sulfate is added at <50°C.
TOOYAMA SHIGEYUKI
NUMATA YOSHIHIKO
