Papers by Author: Meng Ying Li

Abstract: This paper describes the synthesis and surface characterization of a new silica white prepared from a high Si:Al fine powder by using the sulfuric acid precipitation method. In the beginning, water and alkali are added to the sieved high Si:Al fine powder. The mixed liquid is then heated until it is boiling and left alone at the same temperature for 2.5 hours before it is filtrated. Applying liquid NaCl (20%) to the filtrated solution before it is heated to 80°C. Applying certain amount of surfactant and H₂SO₄ (20%) while maintaining the temperature at 80°C for 3 hours before it is washed, precipitated, filtrated, and dried to produce the final product of silica white. Examinations with XRD and IR show that the silica white is amorphous silicon. It has a PH value of 7-7.5 determined by aqueous suspension method, a white index of 96% and above, a volume average particle diameter of 4.6 - 7.1 µm, a specific surface area of 95.5-103.1 m2/g, an oil absorption rate of 4.34-4.87 ml/g, and a LOI (loss on ignition) of 5.12% at 1000°C. The synthesized silica white has a satisfying uniformity of particle sizes, meeting standard of HG/T 3061-1999.

Abstract: Type-A zeolites molecular sieve is prepared after crystallization of the type-A zeolites molecular sieve precursor, which is prepared from Stellerite, at temperature of 90 ~ 100°C for 6 hours. It has a complete structure, with crystallinity of 98%, volume average particle size of 3.72µm and particle size distribution which is less than 10µm over 90%. Multi-member rings structure in the type-A zeolites molecular sieve cover each other, forming the cage (β-cage, α-cage, octahedral cage) structure. Nuclei and nanometer particles are formed after the further congregation reaction, and then gather and grow, result in the formation of nanometer crystal particles and transformation to micrometer particles.