Sulfuric Acid → Phosphoric Acid

HRID 894499

Reaction equation

[S:1](=[O:5])(=[O:4])([OH:3])[OH:2].[P:6]([OH:10])([O-:9])([O-:8])=[O:7].[Ca+2:11]>>[P:6](=[O:7])([OH:10])([OH:9])[OH:8].[OH2:2].[S:1]([O-:5])([O-:4])(=[O:3])=[O:2].[Ca+2:11].[Ca+2:11].[S:1]([O-:5])([O-:4])(=[O:3])=[O:2]

Participants

Reactant 2

HCID 1118Sulfuric Acid2×

HCID 24441Calcium hydrogen phosphate

Product 2

HCID 1004Phosphoric Acid

HCID 3033839Calcium Sulfate, Hemihydrate

Procedure

Concentrated sulfuric acid is added to the slurry as it enters the second tank. Monocalcium phosphate reacts with the sulfuric acid forming phosphoric acid and calcium sulfate hemihydrate. An excess of sulfuric acid will usually be used (see Table 4). A portion of the slurry is recycled back to the first tank where more pebble rock and recycle phosphoric acid are added. Another portion of the slurry is sent to the filtration stage. The first quantity of acid recovered is product acid containing from about 40% to about 47% P2O5. The solids from the slurry after filtration, are washed and the resulting filtrate containing about 30% P2O5 is recycled back to the first tank.

Sources & evidence

ORD record: ord-3a677b7c63f643a7bb630f38c665213f
Source dataset: uspto-grants-1981_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04284614

Linked notes

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