Process for preparation of abrasive precipitated silica
US6521214B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2000 |
| Grant date | Feb 18, 2003 |
| Priority date | — |
| Expiry date | Aug 16, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/60
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A process for the preparation of precipitated silica is disclosed. The precipitated silica has a refractive index from about 1.440 to about 1.450, among other properties. The silica is prepared by a method including; a first step of using an initial feedstock of water, an electrolytic salt and a fraction of the total amount of silicate employed; a second step including preneutralizing the feedstock with the acidifying agent until about 50 to 85% of the amount of M2O present has been neutralized; a third step including introducing into the preneutralized feedstock the remaining fraction of alkali metal silicate in aqueous solution and the acidifying agent, under conditions such that the pH of the reaction medium remains substantially constant and from about 8.6 to about 9.6; a fourth step including, after the addition of silicate is stopped, in continuing the addition of acidifying agent until the medium reaches a pH of about 7 to 8; a fifth step including, after maturation, in continuing the acidification of the reaction medium until a silica broth with a pH of about 3.7 to 4.6 is obtained; wherein the consolidation ratio CR of the process is less than or equal to 7, and the separa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.