| 摘要 |
<p>This invention provides a process for the conversion of hazardous hexafluoroarsenic acid or a salt thereof to an arsenate salt that can be rendered non-hazardous. In particular, hexafluoroarsenic acid or a salt thereof is converted to the solid insoluble calcium or magnesium arsenates or mixtures thereof which are water insoluble. Known stabilization technology renders the material non-hazardous. The present process involves converting hexafluoroarsenic acid or a salt thereof contained in an aqueous mixture to an insoluble arsenate salt. The process comprises the steps of: (a) adding a first compound selected from group (I) or group (II) to the aqueous mixture in an amount sufficient to substantially neutralize the aqueous mixture to a pH greater than or equal to about 10; and, if the first compound is selected from group (II), in an amount sufficient to substantially convert fluoride ions to solid water insoluble calcium or magnesium fluorides or mixtures thereof and to substantially hydrolyze the hexafluoroarsenic acid or salts thereof to solid water insoluble calcium or magnesium arsenates or mixtures thereof in subsequent step (b), and if the first compound is selected from group (I), adding a second compound from group (II) in an amount sufficient for said conversion of fluoride ions and said hydrolysis; and (b) reacting the mixture resulting from step (a) at a temperature and for a time sufficient for said conversion of fluoride ions and said hydrolysis. Prior to said step (a), the process further has the benefit of recovering the hydrogen fluoride from the starting aqueous mixture as a product if desired or for decreasing the volume of waste to be rendered non-hazardous.</p> |
