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WWW.PRAYON.COM

PRAYONTECHNOLOGIES

PROCESSWITHINITIAL

HEMIHYDRATEREACTION

TWO-CRYSTAL PROCESS OR PH2

[ PRAYON HEMIHYDRATE 2-CRYSTAL ]

After the first reaction in hemihydrate

mode, the product acid is separated as

a 46% P

2

O

5

with low SO

3

content. The

remaining

α-

hemihydrate, washed with

recycled liquor, is further processed

with sulphuric acid in conditions in

which

α-

hemihydrate is unstable and

recrystallises as gypsum, releasing

cocrystallised and unreacted P

2

O

5

.

THE MAIN CHARACTERISTICS OF

THE PROCESS ARE

+

high-strength phosacid

+

high P

2

O

5

recovery (> 98.5%)

RECOMMENDED FOR LOCATIONS

+

with medium - high-cost rock

+

with high-cost energy

+

with easy gypsum disposal

Phosphate

Water

Phosphoric Acid

40 to 46% P

2

O

5

Pure Calcium

Sulphate

Dihydrate

H

2

SO

4

Reaction

Recycled Acid

Digestion

DIHYDRATE

HEMIHYDRATE

Vacuum

Vacuum

Separation filter

Dihydrate

Filter

Vacuum

Flash

Cooler

Optional

Flash Cooler

Hydratation tanks