PURPOSE: To obtain spherical silica fine powder controlled in a pore structure by controlling the viscosity of silicate ion-containing aq. soln. as the indication of the polymerization degree of the silicate ion and thermal decomposition temp. in a atomized combustion method.
CONSTITUTION: In the production method for the atmized combustion method spherical silica in which the aq. soln. containing the silicate ion consisting of alkoxy-silicon, water and small amount of acid is changed into misty state by an ultrasonic vibrator, then the mist is introduced to a high temp. heating combustion device together with air or gaseous oxygen to decompose by heat, the objective spherical silica powder is obtained by controlling the viscosity of silicate ion-containing aq. soln. as the indication of the polymerization degree of the silicate ion and thermal decomposition temp. The concn. of silicate ion in the silicate ion aq. soln. is within the range of 0.05-2.0mol/l. When the concn. is ≤0.05mol/l, the efficiency of an oxide powder production is low, and the concn. is ≥2.0mol/l, the gelation of the silicate ion is liable to occur according to the progress of an aging, and it becomes difficult to maintain a solution state, on the other hand, the acid amount to be added is required to be 0.01-0.03 times per the concn. of the silicate ion.
TSUNODA NORIYOSHI
MIZUSHIMA IKUTOMO
TANABE TAKAHIRO
