Patent ID: 9527750
Filing Date: 2016-12-27
CPC Classification: C01B,C01F,Y10T

Claim Text:
1. A method for producing hollow nanoparticles having an average particle size of 30 to 300 nm and each comprising a shell mainly comprising calcium silicate, the method comprising: forming core-shell particles each comprising a core particle containing calcium and, on a surface of the core particle, a coating layer comprising amorphous silica; converting each coating layer of each core-shell particle into a shell mainly comprising calcium silicate by hydrothermal treatment of the core-shell particles at a hydrothermal treatment temperature in a range of equal to or greater than 150° C. and less than 200° C. for a hydrothermal treatment period of at least 120 hours; and removing each core particle from each core-shell particle while allowing each shell of each core-shell particle to remain.