| 摘要 |
PROCESS FOR THE SEPARATION OF ARSENIC ACID FROM A SULFURIC ACID-CONTAINING SOLUTION The present invention provides a process for the separation of arsenic acid from a solution which comprises sulfuric acid, water, and arsenic acid. In step (a), the solution is reacted with copper or a copper-containing compound in an amount sufficient and at a temperature sufficient to produce copper arsenate. In step (b), an alkali solution is added to the solution resulting from step (a) in an amount sufficient to precipitate the produced copper arsenate and solubilize the sulfate salt of the alkali. In step (c), the precipitated copper arsenate is separated from the solution resulting from step (b). The separated copper arsenate can then be used in the preparation of intermediates which can be converted to wood preservatives. In step (d), a soluble ferric-containing compound is added to the solution resulting from step (c) in an amount sufficient to reduce residual arsenic in the solution. In step (e), the ferric arsenate formed is separated from the solution resulting from step (d). The separated ferric arsenate can be disposed of properly. The filtrate comprises about 85 to about 90 percent by weight water, about 10 to about 15 percent by weight sodium sulfate, and below about 0.79 parts per million of arsenic; this filtrate is considered nonhazardous and can be discharged to waste ponds. 6881k
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