Phosphorus oxide (P4O10) → Phosphoric Acid

Participants

Reaction Steps

25 kg/hr of acid and 3 kg of recycled scrubbing raffinate were treated, at temperatures between 20° and 30°C, in a system comprising two mixers with settling tanks, with 158 kg/hr of anhydrous amyl alcohol originating from an OXO reaction. 184 kg/hr of an alcoholic phosphoric acid solution and 2 kg of an almost solid raffinate were obtained. The raffinate, which contained 3.2 weight % of P2O5, based on the P2O5 used, was decanted and discarded. The alcoholic phosphoric acid solution saturated with water was scrubbed in a countercurrent operation, in a system comprising six mixers provided with settling tanks, by means of 2.8 kg/hr of circulated purified phosphoric acid containing 23.4 weight % of P2O5. The resulting scrubbing raffinate was combined with crude acid and the whole was treated once again with the alcohol. The purified alcoholic phosphoric acid solution was contacted, in a system comprising eight mixers provided with settling tanks, with 19 kg/hr of water. 30 kg/hr of purified phosphoric acid containing 23.4 weight % of P2O5 was thus obtained, together with 171 kg/hr of alcohol saturated with water. The alcohol, which contained less than 0.1 % of phosphoric acid, was dehydrated by distilling it under a pressure of 100 mm of mercury. 13 kg/hr of water containing approximately 1 % of residual alcohol was obtained. It was recycled and used for the re-extraction of phosphoric acid from the alcoholic phosphoric acid solution. The phosphoric acid was analyzed and found to contain the following impurities in ppm based on % P2O5 :Fe <30 Mn 2 SiO2 <100Al <50 As 1 F <100Ca <20 SO4 <500Mg <20V 5______________________________________

Provenance & Evidence