PRODUCTION AND CONCENTRATION OF SILICA SOL

Japanese Patent JP3446057

B2

PURPOSE: To economically and easily obtain aq. alkaline silica sols with the lowest energy consumption by being reacted in a multistage cascade and conducting the concn. by ultrafiltration, while continuously adding acidic fresh sols and an alkaline reagent to an aq. colloidal silica sol soln.
CONSTITUTION: The acid fresh sols, which incorporate 4 to 8 wt.% SiO2 with pH 2 to 4 in a particle form 2 to 4 nm, are added to a starting medium which incorporates the aq. colloidal silica sol soln. of pH ≥8 containing 2 to 14 wt.% SiO2 having 4 to 16 nm particle size, and simultaneously, the alkaline reagent in the quantity, with which the pH value is not lowered below pH 8 over the entire process, is added to this starting medium at ≥60°C. The addition of the acid fresh sols and the alkaline reagent are continued until the average size of the particle attains >4 nm. The particles are designed to be expanded in a multistage cascade, the first stage incorporates the staring medium and in which compsns. to be added are continuously supplied. For concn., the ultrafiltration is carried out with an alkali-resistant film with a cutoff value of ≤30,000 dalton, preferably ≤15,000 dalton.

Ube Brekaw
Andreas Nickel
Hans-Dater Block
Hans-Heinrich Morett
Peter Schmitt
Peter Schoever
Bernard Ludofushi

JP13253193A

September 16, 2003

May 11, 1993

Click for automatic bibliography generation  

Bayer Aktiengesellschaft

B01D61/14; B01D71/00; B01J13/00; C01B33/143; C01B33/148; C01B33/151; (IPC1-7): C01B33/143; B01D61/14

JP5490100A
JP63285112A
JP1126216A
JP627622A

Heikichi Odashima

Previous Patent: DEVICE FOR DIVIDING DATA

Next Patent: PNEUMATIC TIRE WITH REDUCED ROLLING RESISTANCE