Method of producing granular amorphous silica
US5989510A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1996 |
| Grant date | Nov 23, 1999 |
| Priority date | — |
| Expiry date | Jun 17, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/80
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method of directly precipitating a spherical amorphous silica in a high yield by adding a carboxymethyl cellulose (CMC) as a coagulation growing agent in a step of neutralizing the alkali silicate with an acid. The CMC having a particular etherification degree and a particular polymerization degree is added in an amount of from 1 to 100% by weight reckoned as SiO.sub.2 with respect to silica in the alkali silicate, whereby the whole silica particles turn into spherical amorphous silica particles having high sphericalness. There can be obtained spherical amorphous silica particles having a BET specific surface area of from 25 to 800 m.sup.2 /g, an apparent specific gravity of from 0.1 to 0.8 and a particle diameter of from 0.2 to 50 .mu.m cheaply and in a high yield.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.