Process for separating arsenic acid from an aqueous mixture comprising sulfuric and arsenic acids
US5449503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1994 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Aug 26, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B17/907
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a process for recovering arsenic acid from a starting mixture comprising sulfuric and arsenic acids and water. In step (a), the starting mixture is treated with a sulfur (IV) compound which will reduce the arsenic acid to arsenic (III) compound under conditions sufficient to substantially convert the arsenic acid to arsenic (III) wherein the resulting mixture comprises arsenic (III) compound, the sulfur (IV) compound, sulfuric acid, and water. In step (b), the resulting mixture is purged with gas to substantially remove the sulfur (IV) compound from the mixture wherein the purged mixture comprises the arsenic (III) compounds, sulfuric acid, and water. In step (c), the purged mixture is treated under conditions sufficient to substantially separate the arsenic (III) compounds from the purged mixture. In step (d), the separated arsenic (III) compound is reacted with an oxidizing agent to substantially convert arsenic (III) compound to arsenic acid wherein the final mixture comprises arsenic acid, unreacted oxidizing agent, and water. In step (e), impurities are removed from the final mixture to provide substantially pure aqueous arsenic acid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.