Abstract: Process of acid attack with sulphuric acid of a phosphate source comprising calcium or not comprising calcium for a predetermined time period ranging from 20 to 180 minutes in the conditions wherein the molar ratio of sulphate from the sulphuric acid and possibly from the phosphate source to the calcium present in the phosphate source ranges from 0.6 to 0.8, and the content in P2O5 in the attack tank is of less than 6%.

Abstract: Process of acid attack with sulphuric acid of a phosphate source comprising calcium or not comprising calcium for a predetermined time period ranging from 20 to 180 minutes in the conditions wherein the molar ratio of sulphate from the sulphuric acid and possibly from the phosphate source to the calcium present in the phosphate source ranges from 0.6 to 0.8, and the content in P2O5 in the attack tank is of less than 6%.

Abstract: A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO3 equal to or less than 1.5% and a content of free P2O5, a conversion of at least part of said first slurry by heating to a temperature greater than 80° C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of ?-calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure ?-calcium sulphate hemihydrate.

Abstract: This disclosure relates to a method for the preparation of calcium monohydrogen phosphate comprising an etching in an aqueous medium, during a predetermined time period, a source of phosphate with an acid with formation of a pulp comprising an aqueous phase containing calcium phosphate in solution and a solid phase containing impurities, a first separation between said aqueous phase and said solid phase, during a predetermined time period, a neutralization of said aqueous phase at a sufficient pH to obtain a precipitation of said calcium monohydrogen phosphate, a second separation between said aqueous medium and said calcium monohydrogen phosphate, characterized in that said predetermined time period of said step a) of digestion is greater than that of said step b).

Abstract: This present invention disclosure relates to a method for the preparation of calcium monohydrogen phosphate comprising an etching in an aqueous medium, during a predetermined time period, of a phosphate source with an acid with formation of a pulp comprising an aqueous phase containing calcium phosphate in solution and a solid phase containing impurities, a first separation between said aqueous phase and said solid phase, during a predetermined time period, a neutralization of said aqueous phase at a sufficient pH to obtain a precipitation of said calcium monohydrogen phosphate, a second separation between said aqueous medium and said calcium monohydrogen phosphate, characterized in that said first separation of said step b) is carried out at a filtration rate of at least 0.1 ton of P2O5/??P/m2/day.

Abstract: A method for preparing calcium sulphate comprising a production of DCP by the attack of a source of phosphate by an acid, a digestion of the isolated DCP by the sulphuric acid under conditions giving rise to the formation of a first slurry of gypsum suspended in an acidic aqueous phase having a content of free SO3 equal to or less than 1.5% and a content of free P2O5, a conversion of at least part of said first slurry by heating to a temperature greater than 80° C. and potentially by adding sulphuric acid, with solubilisation of the gypsum crystals and recrystallisation of the solubilised calcium sulphate in a second slurry of ?-calcium sulphate hemihydrate crystals suspended in an aqueous phase based-on phosphoric acid, wherein the content of free SO3 is less than 10% by weight, and a separation between said aqueous phase and a filter cake based on particularly pure ?-calcium sulphate hemihydrate.

Abstract: A method and device for producing polyphosphoric acid burns a fuel in combustion air in a combustion chamber, sprays a spray fluid comprising substantially pure orthophosphoric acid and undertakes polymerization-condensation of the pure orthophosphoric acid. A polyphosphoric acid in the form of an acid mist accompanied by formation of gases which mix with combustion gases resulting from burning of the fuel is formed to reach a predetermined temperature, wherein the mixture causes sudden lowering of combustion gas temperature. The acid mix is separated from the gas mixture and the polyphosphoric acid is collected at a bottom of the combustion chamber and the gas mixture is outputted via a lower part of the combustion chamber separate from the collection of polyphosphoric acid.

Abstract: The invention relates to a method for producing phosphoric acid, including: attacking phosphate rock by means of sulfuric acid between 70° and 90° C. with formation of a first calcium sulfate dihydrate crystal slurry, the aqueous acid phase of said slurry having free P2O5 content between 38 and 50 wt % and free SO3 content that is less than 0.5 wt % and greater than 0.05 wt %; converting said first slurry by means of heating at a temperature greater than 90° C., thus giving rise to a second slurry formed of calcium sulfate hemihydrate crystals; and, within the second slurry, separating a produced phosphoric acid, having a free SO3 content that is less than 2%, and a calcium sulfate hemihydrate filter cake.

Abstract: A method and device for producing polyphosphoric acid burns a fuel in combustion air in a combustion chamber, sprays a spray fluid comprising substantially pure orthophosphoric acid and undertakes polymerization-condensation of the pure orthophosphoric acid. A polyphosphoric acid in the form of an acid mist accompanied by formation of gases which mix with combustion gases resulting from burning of the fuel is formed to reach a predetermined temperature, wherein the mixture causes sudden lowering of combustion gas temperature. The acid mix is separated from the gas mixture and the polyphosphoric acid is collected at a bottom of the combustion chamber and the gas mixture is outputted via a lower part of the combustion chamber separate from the collection of polyphosphoric acid.

Abstract: A method and device for producing polyphosphoric acid burns a fuel in combustion air in a combustion chamber, sprays a spray fluid comprising substantially pure orthophosphoric acid and undertakes polymerization-condensation of the pure orthophosphoric acid. A polyphosphoric acid in the form of an acid mist accompanied by formation of gases which mix with combustion gases resulting from burning of the fuel is formed to reach a predetermined temperature, wherein the mixture causes sudden lowering of combustion gas temperature. The acid mix is separated from the gas mixture and the polyphosphoric acid is collected at a bottom of the combustion chamber and the gas mixture is outputted via a lower part of the combustion chamber separate from the collection of polyphosphoric acid.

Abstract: A method for producing phosphoric acid, comprising attack in an aqueous medium of phosphated rock with sulfuric acid, with formation of a first dihydrate slurry suspended in an aqueous phase having a free P2O5 content between 38 and 50% and a free SO3 content of less than 0.5%, conversion of this first slurry by heating with recrystallization of the solubilized calcium sulfate giving rise to a second hemihydrate slurry, and separation in the second slurry between a production phosphoric acid and a hemihydrate cake, characterized in that it comprises during the attack, addition of a fluorine source in the first slurry in a content from 1% to 5% by weight of F relatively to the P2O5 contained in the phosphated rock.

Abstract: The invention relates to a filtration cell that comprises a tank with a bottom wall (2) and four side walls extending upwards from the bottom wall as well as an upward opening, the four side walls including two opposite longitudinal walls (3, 5) as well as a front facing wall (4) and a rear facing wall connecting them, a filtration bed (7) supported in the tank, an outlet opening for discharging the filtrate, and a covering flap (24) protruding outwards from the top of one of said longitudinal walls, the longitudinal wall (5) opposed to that fitted with the flap including a lower portion (25) extending upwards from the bottom wall (2) and an upper portion (26) extending slantedly upwards and inside the tank from the top of said lower portion (25), and/or the front facing wall (4) comprises a bottom portion (27) extending upwards from the bottom wall (2) and a top portion (28) extending slantedly upwards and inside the tank from the top of said bottom portion (27).

Abstract: A continuous fluid filtration device having filtration cells disposed in a carousel around a rotation axis so as to be able to pivot about a tilt axis including apparatus for discharging the filtrate from the cells with at least one outlet orifice at the bottom of each cell, a central collector and a connection allowing flow of the filtrate between the outlet orifice and the collector, where the connection for each cell includes a flexible conduit in which, in the filtration position of the cell, no area of the flexible conduit is lower than another area of the conduit situated downstream with respect to the flow of the filtrate, the flexible conduit being arranged so as not to undergo any elongation during tilting of the cell.