Agency of Industrial Science and Technology

Japan As Represented by Director General of Agency of Industrial Science

Eiichi Abe

Shuji Tsunematsu

Hideharu Hirosue

Hideo Yamada

Kozo Inoue

A novel method is proposed for the preparation of a calcium silicate powder particularly useful as a filter aid in the filtration of an acidic aqueous liquid by virtue of the extremely high acid resistance of the calcium silicate powder. The inventive method comprises a hydrothermal reaction of a blend of a silica-containing material and calcium oxide or hydroxide in a specified molar ratio under specified reaction conditions to form calcium silicate, which is then subjected to a heat treatment at 800.degree.-1200.degree. C. for 0.5-2 hours. An improvement can be obtained in the clarity of the filtrate obtained by the filtration using the calcium silicate powder prepared by the inventive method as a filter aid when the hydrothermal reaction for the preparation thereof is conducted in an aqueous solution of potassium hydroxide in a specified concentration.

Method for the preparation of acid-resistant calcium silicate

Method and apparatus for continuously coating discrete particles in a turning fluidized bed formed in a cylindrical coating vessel with a rotary disk at the bottom thereof by blowing hot air into the vessel through air blow holes located between the circumference of the disk and cylindrical side wall of the vessel while spraying a coating material into contact with the particles in the turning fluidized bed, characterized by introducing a particulate raw material and a coating material into the turning fluidized bed at constant feed rates; and discharging coated particles at the same rate as the feed rate of the particulate raw material through a particle discharge port located at such a height as to guarantee an average residence time corresponding to a desired coating rate under given operating conditions including the feed rate of the raw material, the rotational speed of the disk and the feed rate of hot air.

Growing community of inventors

Tosu, Japan

Eiichi Abe