The invention belongs to the technical field of
silicon dioxide, and particularly relates to a preparation method of low-specific-surface-area high-oil-absorption-value friction type
silicon dioxide.The preparation method comprises the steps that S1, 8-12 m<3> of
ethanol aqueous solution is injected and heated to 60-70 DEG C, and stirring starts; S2, water glass and
sulfuric acid are added dropwise to carry out a parallel flow reaction, the pH value in the reaction process is controlled to be 6.0-6.8, meanwhile, absolute ethyl
alcohol is added every 5-10 minutes in the reaction process to keep the volume ratio of ethyl
alcohol to water in a
reaction system to be 1:(3-7), after the water glass is dropwise added, dropwise addition of
sulfuric acid is stopped, and stirring continues; S3, stirring and heating are stopped, aging is conducted for one hour, and pressure
filtration, washing,
drying and crushing are conducted on the on formed
silicon dioxide to prepare
silicon dioxide. The
silicon dioxide has the advantages of a low in specific surface area, a high
oil absorption value, a high water absorption amount, the friction property and the like;
toothpaste has good friction and cleaning performance after the
silicon dioxide is used, and meanwhile, the problem of expansion of the
viscosity of the
toothpaste is well solved.