Alliedsignal Inc.

Douglas G Frick

Charles L Redmon

Robert A Smith

Somanahalli N Subbanna

The present invention provides a process for the conversion of hazardous hexafluoroarsenic acid or any salt thereof to arsenic acid or salt thereof which can be rendered nonhazardous. In particular, the hexafluoroarsenic acid or salt is converted to arsenic acid or salt which can be converted to a water insoluble salt. Known insolubilization and stabilization technology then renders the material nonhazardous. The present process involves converting hexafluoroarsenic acid or salt thereof contained in an aqueous mixture to arsenic acid or salt thereof. The process comprises the steps of: (a) adding acid selected from the group consisting of sulfuric acid, arsenic acid, perchloric acid, and mixtures thereof to the aqueous mixture in an amount sufficient to catalyze the hydrolysis of the hexafluoroarsenic acid or salt thereof and raising the temperature of the aqueous mixture before, during, or after the acid addition sufficient to remove substantially all of the hydrogen fluoride in subsequent step (b); (b) passing an inert gas through the heated acid mixture steam in a quantity sufficient to remove substantially all of the hydrogen fluoride in the heated acid mixture from the heated acid mixture; and (c) separating substantially all of the hydrogen fluoride from the heated acid mixture whereupon the hexafluoroarsenic acid or salt thereof converts substantially to arsenic acid or salt thereof.

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both or Orchard Park, NY, United States of America

Douglas G Frick