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US 4,305,915 AGranted
Stabilized wet process phosphoric acid
AssigneeW. R. Grace & Co.
InventorRichard N. Hill
Life of this patent
Estimating the term…
Abstract
Wet-process phosphoric acid products substantially free of post precipitation.
Claims16
As a new composition of matter, unfiltered wet-process phosphoric acid substantially free of post-precipitation, analyzing:
- ______________________________________ Component Wt. % ______________________________________ P.sub.2 O.sub.5 57-63 Solids 0-2 SO.sub.4 as H.sub.2 SO.sub.4 3.5-5 Fe.sub.2 O.sub.3 1.1-2 Al.sub.2 O.sub.3 1.1-2 Sum of CaO, SiO.sub.2 F, Na.sub.2 O, K.sub.2 O, and MgO 1.1-3.6 ______________________________________ said acid characterized in that
- (a) the solids if any remain substantially suspended and settle out in only small amounts;
- (b) the solids if any whether suspended or settled, remain soft, free-flowing, and non-caking;
- (c) said acid is readily pumped from storage and does not cake over outlets, valves, and accessory mechanisms;
- and
- (d) the said acid can be ammoniated without substantial foaming.
3 more elements
As a new composition of matter, an unfiltered wet process phosphoric acid product substantially free from post precipitation, and having the following analysis:
- ______________________________________ Wt. % ______________________________________ P.sub.2 O.sub.5 58-60 Solids 0.0-0.5 H.sub.2 SO.sub.4 3.0-6.0 CaO 0.01-0.10 SiO.sub.2 0.0-0.03 F 0.35-0.65 Fe.sub.2 O.sub.3 1.0-3.0 Al.sub.2 O.sub.3 1.0-3.0 Na.sub.2 O 0.02-0.17 K.sub.2 O 0.01-0.12 MgO 0.3-0.7 ______________________________________
- said acid characterized in that
- (a) the solids if any remain substantially suspended and settle out in only small amounts;
- (b) the solids if any whether suspended or settled, remain soft, free-flowing, and non-caking;
- (c) said acid is readily pumped from storage and does not cake over outlets, valves, and accessory mechanisms;
- and
- (d) the said acid can be ammoniated without substantial foaming.
4 more elements
A wet process phosphoric acid substantially free from post-precipitation, analyzing:
- ______________________________________ Component Wt. % ______________________________________ P.sub.2 O.sub.5 57-63 Solids 0-2 SO.sub.4 as H.sub.2 SO.sub.4 3.5-5 Fe.sub.2 O.sub.3 1.1-2 Al.sub.2 O.sub.3 1.1-2 Sum of CaO, SiO.sub.2 F, Na.sub.2 O, K.sub.2 O, and MgO 1.1-3.6 ______________________________________
- said acid characterized in that
- (1) the solids if any remain substantially suspended and settle out in only small amounts.
- (2) the solids if any whether suspended or settled, remain soft, free-flowing, and non-caking;
- (3) said acid is readily pumped from storage and does not cake over outlets, valves, and accessory mechanisms;
- and
- (4) the said acid can be ammoniated without substantial foaming, said acid having been
- made by a method that includes the steps:
- (a) to a wet process phosphoric acid having a P.sub.2 O.sub.5 content of 22 to 46 weight percent from which the suspended solids have been removed, adding 0.05 to 2.0 weight percent aluminum silicate based on the contained weight of P.sub.2 O.sub.5 in the acid to provide an aluminum silicate acid mix, said aluminum silicate being finely divided so as to be soluble in the phosphoric acid as the concentration of the acid is increased from 22-46 weight percent P.sub.2 O.sub.5 to 48-50 weight percent P.sub.2 O.sub.5 ;
- (b) concentrating the aluminum silicate acid mix to said 48-50 weight percent P.sub.2 O.sub.5 in an evaporation zone thereby to provide an aluminum silicate/acid solution;
- (c) transferring the concentrated solution to a crystallizing zone having a product stream nearly free of crystals formed in the said zone;
- (d) recovering the product stream;
- and
- (e) concentrating the product stream to about 57-63% P.sub.2 O.sub.5.
11 more elements
A wet process phosphoric acid substantially free from post-precipitation, analyzing:
- ______________________________________ Component Wt. % ______________________________________ P.sub.2 O.sub.5 57-63 Solids 0-2 SO.sub.4 as H.sub.2 SO.sub.4 3.5-5 Fe.sub.2 O.sub.3 1.1-2 Al.sub.2 O.sub.3 1.1-2 Sum of CaO, SiO.sub.2 F, Na.sub.2 O, K.sub.2 O, and MgO 1.1-3.6 ______________________________________
- said acid characterized in that
- (1) the solids if any remain substantially suspended and settle out in only small amounts;
- (2) the solids if any whether suspended or settled, remain soft, free-flowing, and non-caking;
- (3) said acid is readily pumped from storage and does not cake over outlets, valves, and accessory mechanisms;
- and
- (4) the said acid can be ammoniated without substantial foaming, said acid having
- made by a method that includes the steps:
- (a) to a wet process phosphoric acid having a P.sub.2 O.sub.5 content of 22 to 35 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 22-35 weight percent P.sub.2 O.sub.5 to 48-50 weight percent P.sub.2 O.sub.5 ;
- (b) concentrating the perlite-acid mix to said 48-50 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 a product stream containing most of the crystals formed in the said zone;
- (d) recovering the product stream;
- and
- (e) concentrating the product stream to about 57-63% P.sub.2 O.sub.5.
11 more elements
Dependencies are inferred from the claim text.