HIGHLY ABRASIVE AND HIGHLY TRANSPARENT SILICA FOR USE IN TOOTHPASTE AND PREPARATION METHOD THEREOF

摘要

Disclosed are a highly abrasive and highly transparent silica for use in toothpaste and a preparation method thereof. The method comprises S1: adding a sodium sulfate solution into a reaction tank and raising the temperature to 60-65ºC; S2: adding a sodium silicate solution while stirring and raising the temperature to 60-65ºC, adding a sulfuric acid solution dropwise until a pH of 8.5 to 9.5 is reached, upon which acid addition is stopped and the resulting mixture is allowed to age; S3: adding a sodium silicate solution and a sulfuric acid solution at the same time to allow reaction at a pH controlled to be 8.0-9.0, and when the addition of the sodium silicate solution is complete, continuing to add the sulfuric acid solution dropwise until a pH of 4.5 to 5.0 is reached; and S4: subjecting silica thus formed to pressure filtering, washing, spray drying, and airflow breaking to obtain the silica. The silica obtained by the method has a light transmittance of ≥90% at a refractive index in the range of 1.448 to 1.460, and a copper loss value of ≥15mg, and thus has a high light transmittance at a high refractive index, and a high abrasion and cleaning performance at the same time.