Process for producing ammonium thiosulfate
US6534030B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2001 |
| Grant date | Mar 18, 2003 |
| Priority date | — |
| Expiry date | Mar 14, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2257/406
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for producing ammonium thiosulfate by contacting a feed gas containing hydrogen sulfide and ammonia with an aqueous absorbing stream containing ammonium sulfite and ammonium bisulfite to form an ammonium thiosulfate-containing solution; the absorption being controlled by monitoring the oxidation reduction potential of the absorbing stream and varying the feed rates in response to the oxidation reduction potential measurements. An ammonium bisulfide-containing aqueous stream is contacted with and absorbs sulfur dioxide to form an aqueous stream containing the ammonium sulfite and ammonium bisulfite reagents. This sulfite/bisulfite-containing stream is combined with the ammonium thiosulfate-containing solution in a vessel to produce a combined solution. A portion of the combined solution is recycled back to contact the feed gas and ammonium thiosulfate is recovered from the remaining portion of the combined solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.