Potash Corporation of Saskatchewan

Gary D Derdall

William R Erickson

Robin L Phinney

James D Wilson

Alfred Wong

An apparatus for producing phosphoric acid by the recovery of P.sub.2 O.sub.5 from a phosphate ore is disclosed. A slurry of a phosphate ore in an aqueous phosphoric acid solution is formed in each of a plurality of reaction zones connected in series. Phosphate ore is introduced into the first reaction zone and phosphoric acid into the last reaction zone whereby the reaction of the phosphoric acid with the ore forms a slurry of coarse solids, fine solids and monocalcium phosphate in the phosphoric acid solution. A first process stream comprising coarse solids is removed from the first reaction zone and each of the other reaction zones and is tranferred to the adjacent, successive reaction zone. A second process stream comprising fine solids is removed from the last reaction zone and the other reaction zones and is transferred into the adjacent, preceding zone in a direction which is countercurrent to the direction of flow of the first process stream and is concurrent with the direction of flow of the phosphoric acid from the last to the first reaction zones. A differential of phosphoric acid concentration is maintained between the reaction zones with the concentration decreasing in each reaction zone in the direction of flow of the first process stream.

Apparatus for producing phosphoric acid from phosphate ore

A process and apparatus for producing phosphoric acid by the recovery of P.sub.2 O.sub.5 from a phosphate ore is disclosed. A slurry of a phosphate ore in an aqueous phosphoric acid solution is formed in each of a plurality of reaction zones connected in series. Phosphate ore is introduced into the first reaction zone and phosphoric acid into the last reaction zone whereby the reaction of the phosphoric acid with the ore forms a slurry of coarse solids, fine solids and monocalcium phosphate in the phosphoric acid solution. A first process stream comprising coarse solids is removed from the first reaction zone and each of the other reaction zones and is transferred to the adjacent, successive reaction zone. A second process stream comprising fine solids is removed from the last reaction zone and the other reaction zones and is transferred into the adjacent, preceding zone in a direction which is countercurrent to the direction of flow of the first process stream and is concurrent with the direction of flow of the phosphoric acid from the last to the first reaction zones. A differential of phosphoric acid concentration is maintained between the reaction zones with the concentration decreasing in each reaction zone in the direction of flow of the first process stream.

Method for producing phosphoric acid from phosphate ore

Described herein is a process for producing potassium salts from potassium-based liquors for pulping of lignocellulosic material. The process comprises the steps of

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Saskatoon, Canada

Gary D Derdall