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US 4,108,957 AGranted
Method for manufacture of phosphoric acid from phosphate rock
OwnerRobert Michelinventor
Life of this patent
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Abstract
A method is disclosed for the manufacture of phosphoric acid directly from phosphate rock wherein the crushed phosphate rock is mixed with dilute phosphoric acid to form a slurry and the slurry is then heated to produce calcium monophosphate. Thereafter, oxalic acid is added to the slurry to precipitate the calcium therein as calcium oxalate which is separated. The liquid resulting therefrom which contains the phosphoric acid from the rock is then treated conventionally to recover the phosphoric acid therein.
Claims15
A method for the manufacture of phosphoric acid from phosphate rock comprising
- (a) mixing crushed phosphate rock with a stoichiometric excess of phosphoric acid in the presence of water to form a slurry and heating the slurry at a temperature and for a period of time sufficient to convert the rock into a calcium monophosphate;
- (b) adding oxalic acid to the heated slurry to form a slurry of precipitated calcium oxalate therein;
- and
- (c) recovering the phosphoric acid from the slurry resulting from step (b).
1 more element
Dependencies are inferred from the claim text.