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US 4,164,550 AGranted
Production of stabilized wet process phosphoric acid
AssigneeW. R. Grace & Co.
InventorRichard N. Hill
Life of this patent
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Abstract
Treatment of wet process phosphoric acid to inhibit post-precipitation by steps including addition of an aluminum silicate material such as perlite or the like to dilute acid from which a major portion of solids has been removed, concentration of the resulting dilute acid, and removal of resulting precipitate.
Claims15
The method of preparing a wet process phosphoric acid substantially free from post-precipitation that includes the steps:
- (a) to a wet process phosphoric acid having a P.sub.2 O.sub.5 content of 36 to 46 weight percent from which the suspended solids have been removed, adding 0.05 to 2.0 weight percent of an aluminum silicate material based on the contained weight of P.sub.2 O.sub.5 in the acid to provide an aluminum silicate material-acid mix;
- said aluminum silicate material being finely divided so as to be soluble in the phosphoric acid as the concentration of the acid is increased from 36-46 weight percent P.sub.2 O.sub.5 to an increased P.sub.2 O.sub.5 within the range of 42-52 weight percent;
- (b) concentrating the aluminum silicate material-acid mix to said 42-52 weight percent P.sub.2 O.sub.5 in an evaporation zone thereby to provide an aluminum silicate material/acid solution;
- (c) transferring the concentrated solution to a crystallizing zone having an overflow stream and an underflow stream;
- (d) recovering the overflow stream and subsequently evaporating to a concentration of up to 63% P.sub.2 O.sub.5 to provide wet-process phosphoric acid substantially free of post-precipitation.
2 more elements
The method of preparing a wet process phosphoric acid substantially free from post-precipitation that includes the steps:
- (a) to a wet process phosphoric acid having a P.sub.2 O.sub.5 content of 36 to 46 weight percent from which the suspended solids have been removed, adding 0.05 to 2.0 weight percent perlite based on the contained weight of P.sub.2 O.sub.5 in the acid to provide a perlite-acid mix, said perlite being finely divided so as to be soluble in the phosphoric acid as the concentration of the acid is increased from 36-46 weight percent P.sub.2 O.sub.5 to an increased P.sub.2 O.sub.5 within the range 42-52 weight percent;
- (b) concentrating the perlite-acid mix to said 42-52 weight percent P.sub.2 O.sub.5 in an evaporation zone thereby to provide a perlite/acid solution;
- (c) transferring the concentrated solution to a crystallizing zone having an overflow stream and an underflow stream;
- (d) recovering the overflow stream and subsequently evaporating to a concentration of up to 63% P.sub.2 O.sub.5 to provide wet-process phosphoric acid substantially free of post precipitation.
1 more element
Dependencies are inferred from the claim text.