Method for the preparation of acid-resistant calcium silicate
US5750038A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1997 |
| Grant date | May 12, 1998 |
| Priority date | — |
| Expiry date | Mar 7, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J20/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.