Water softening process
US5152904A · kind A · utility
14Cited by
5References
7Claims
0Family size
Assignees
Inventors
Key dates
| Filing date | Jan 16, 1991 |
| Grant date | Oct 6, 1992 |
| Priority date | — |
| Expiry date | Jan 16, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F5/02
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Process for softening hard water by precipitation of calcium carbonate. The hard water is rendered alkaline, e.g. by the addition of sodium hydroxide, and is then contacted with a large excess of calcium carbonate crystals whose size does not exceed 100 microns, whereby precipitation occurs within a short contact time of the order of 2-60 seconds. Upon separation of soft water from calcium carbonate the bulk of the latter is recirculated and excessive amounts are removed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.