Recovery and utilization of gypstack leachate in hemihydrate phosphoric acid process
AssigneeOccidental Chemical Corporation
InventorMichael B. Caesar
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Abstract
Disclosed is a process for treating a waste stream containing calcium sulfate by depositing said waste stream on a gypstack, collecting the leachate from the gypstack, and recovering the P.sub.2 O.sub.5 values therefrom. Also disclosed is apparatus comprising means for depositing a waste stream containing calcium sulfate on a gypstack, means for collecting the leachate from the gypstack, and means for recovering the P.sub.2 O.sub.5 values therefrom. Preferably, at least about 25% of the calcium sulfate is calcium sulfate hemihydrate.
Claims13
In a wet phosphoric acid method where P.sub.2 O.sub.5 values are recovered by dissolving phosphate rock and precipitating calcium sulfate, and pondwater containing solid calcium sulfate is deposited on a gypstack the improvement comprising increasing the recovery of said P.sub.2 O.sub.5 values from said phosphate rock comprising substituting leachate from said gypstack for at least some of said pondwater used in said method.
A method of treating a waste stream which comprises a slurry of calcium sulfate, comprising
- (a) depositing said waste stream on a stack of gypsum;
- (b) collecting leachate that has passed through said stack of gypsum;
- and
- (c) recovering P.sub.2 O.sub.5 values from said leachate.
Dependencies are inferred from the claim text.