Process for removing sulfur from waste waters containing sulfuric acid
US4039649A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1975 |
| Grant date | Aug 2, 1977 |
| Priority date | — |
| Expiry date | Aug 11, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/02
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Process for recovering sulfur from waste waters containing sulfuric acid, comprising reacting in a first step, the waste water with an aqueous solution of ammonium sulfite, separating the formed sulfur dioxide from the solution, reacting the resulting solution in a second step with calcium oxide to form calcium sulfate and an aqueous ammonia solution, vaporizing ammonia therefrom, reducing the calcium sulfate by means of carbon to form calcium oxide and sulfur dioxide, contacting said vaporized ammonia with said sulfur dioxide and with water, thereby forming an aqueous solution of ammonium sulfite, which is joined to that used in the first step and recycling at least a part of the calcium oxide obtained by reduction of the calcium sulfate to the second step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.