PURPOSE: To manufacture novel spherical basic aluminum sulfate by adding a soluble sulfate to a soln. of a basic aluminum salt represented by a specified formula while keeping the soln. at a specified temp.
CONSTITUTION: A soln. of a basic aluminum salt represented by a formula Al(OH)cXd (where X is a univalent anion, c+d=3 and 0.5≤c≤2.55) is kept at 50W90°C, and a soluble sulfate is added to the soln. to obtain spherical particles of novel basic aluminum sulfate represented by a formula Al(OH)a(SO4)b.nH2O (where a+2b=3, 2.30≤a≤2.50, 0.25≤b≤0.35 and 0≤n≤10) or an aggregate of the particles. The sulfate is added at an addition rate at which addition time T required to make the molar ratio of SO4/Al in the soln. (3-c)/2 satisfies 0.5≤ T≤12. 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 0.5W2.55.
TOOYAMA SHIGEYUKI
NUMATA YOSHIHIKO
