Electrodialysis reversal process and apparatus with bipolar membranes
US5240579A · kind A · utility
58Cited by
8References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 11, 1992 |
| Grant date | Aug 31, 1993 |
| Priority date | — |
| Expiry date | Mar 11, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2201/46115
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Water softening by a combination of electrodialysis and calcium carbonate precipitation. The hard feed water or alternatively recycled soft water is rendered alkaline and is then subjected to a treatment by which precipitation of calcium carbonate is induced. One way of bringing about such precipitation consists in passing the alkaline water across a cake of calcium carbonate crystals having a size not exceeding 100 microns, deposited on a filter and being in an at least fifty fold excess over the amount of calcium carbonate to be precipitated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.