Contents 3 Precipitates Forming During Production

The sulphate content of wet acid is generally 2-5% and phosphoric acid losses in the precipitated calcium sulphate (phosphogypsum) are sometimes 3-10%. Most of the fluorine is evolved from the process in gaseous form during acidulation of the rock and consequent evaporation, but some remains in the calcium sulphate and the acid product. Up to 50% of the Cd impurity originally present in the ore is believed to be removed by the calcium sulphate. 

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