Purification process
US4208393A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 14, 1978 |
| Grant date | Jun 17, 1980 |
| Priority date | — |
| Expiry date | Sep 14, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/02
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for the treatment of aqueous sulphuric acid solutions containing dissolved ferrous sulphate comprising forming such a solution containing from 140 to 220 grams/liter free sulphuric acid in a first zone; adjusting the pH value of the solution in this zone to one in the range 3 to 4 by the addition of finely-divided calcium carbonate thereby precipitating calcium sulphate; passing the slurry thus produced to a second zone; adding to the second zone an aqueous solution of sulphuric acid containing from 3 to 80 grams/liter of free sulphuric acid; adjusting the pH value of the mixture in the second zone to one in the range 3.5 to 6 by the addition of finely-divided calcium carbonate thereby precipitating calcium sulphate and thereafter recovering from the second zone calcium sulphate suitable for use in the manufacture of plasterboard.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.