Phosphoric Acid → Phosphorus oxide (P4O10)

Participants

Reaction Steps

Phosphate rock analyzing 68% bone phosphate of lime (tricalcium phosphate) was comminuted to a fineness such that 90% passed a 100-mesh screen. It was delivered to a pre-reactor having dimensions of 3'×6' at a rate of 200 lbs per ton of product using a weigh belt. Simultaneously water at a rate of 76 lb/ton and phosphoric acid (51.4% P2O5) at a rate of 266 lb/ton were also delivered to the prereactor. The phosphoric acid feed was selected to provide a total P2O5 :CaO ratio of 2.16 by weight (equivalent to a mole ratio of 0.85). The amount of water was selected to dilute the phosphoric acid to 40.0%. Anti-foam agent 0.08 lb/ton (Defoamer 2617-M made by Southern Sizing Corporation was used; it is described as an anionic fatty emulsion), was also delivered to the pre-reactor. The mixture was heated with agitation to a temperature of 175°-210° F. by steam injection. Silicon tetrafluoride and carbon dioxide vapors released by the reactants were vented to a scrubber. The rate of feed of ingredients to the pre-reactor and the size of the digester were selected to provide a retention time of 90 minutes for a production rate of 20 tons/hour.

Provenance & Evidence