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Hemi-Dihydrate

About

Sophisticated process to produce phosphoric acid with a high recovery efficiency and low energy consumption

The Prayon HDH Process is a clever technology that maximizes the P₂O₅ strength in the acid and produces a high-quality gypsum.

It consists of an attack of the phosphate rock under hemihydrate conditions. Hemihydrate slurry is filtered on a Prayon tilting pan filter to recover the phosphoric acid. Then, the hemihydrate slurry is hydrated to dihydrate under specific process conditions of temperature and acidity defined by Prayon. Dihydrate slurry is filtered on a Prayon tilting pan filter to recover a high-quality calcium sulfate.

Depending on the rock processed, the ex-filter acid strength is typically 40-45% P2O5 and the typical P2O5 recovery efficiency is 98-99%.

Advantages
Why should we select Prayon HDH Process?

Highest P₂O₅ recovery

Lowest P₂O₅ in the phosphogypsum

Suitable for further applications after drying

Limited grinding of the rock

High strength phosphoric acid

Recommended
Where should Prayon HDH Process be applied?

Where medium- to high-cost rock is accessible

Where low-cost fuel oil or natural gas is available to dry the gypsum

Where gypsum disposal is limited and/or where a potential market for gypsum has been identified

Cement or plaster applications

Where steam supply is a challenge

Get in touch with our experts

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