The Prayon DA-HF Process is a modern process developed and industrially implemented by Prayon. It is an economic and efficient solution to produce phosphoric acid and valuable gypsum as a co-product.
It consists in the attack of the phosphate rock under dihydrate conditions. Then, the gypsum slurry is converted to hemihydrate by the addition of sulfuric acid and steam in a specific circular reactor designed by Prayon. Hemihydrate slurry is filtered on a Prayon tilting pan filter to recover a good-quality calcium sulfate.
Depending on the rock processed, the ex-filter acid strength is typically 32-34% P2O5 and the typical P2O5 recovery efficiency is 97%.