Abstract:
Process for purifying a stream comprising phosphoric acid and a first amount of impurities, wherein: a slurry of phosphoric acid crystals in a water mother liquor is formed; the phosphoric acid crystals are separated from the mother liquor by filtration in a wash column comprising at least one filtering element (4), while a packed bed of crystals coming from the slurry forms near said filtering element (4); the separated phosphoric acid crystals are washed in the wash column by bringing a washing liquid in countercurrent to the crystals in the bed up to a wash front, where the washing liquid recrystallizes, the bed being subjected to a movement in the direction of said wash front (6b); a purified stream comprising phosphoric acid and a reduced amount of impurities is formed by melting at least part of the washed crystals; the purified stream is extracted from the wash column through a product outlet of the wash column; characterized in that water is introduced into said wash column (1), between the wash front (6b) and the product outlet and/or in a melting circuit (8,10,11,21) producing at least part of the washing liquid, and wherein the introduction of the said water decreases the equilibrium temperature of the contents of the melting circuit (8,10,11,21).
Abstract:
The present invention provides an organic phase composition comprising (f) a first solvent (S1 ) characterized by water solubility of less than 10% and by at least one of (a1 ) having a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa 1/2 and (b1 ) having a Hydrogen bonding related component of Hoy's cohesion parameter (delta-H) between 5 and 20 MPa 1/2 ; (g) a second solvent (S2) characterized by a water solubility of at least 30% and by at least one of (a2) having delta-P greater than 8 MPa 1/2 and (b2) having delta-H greater than 12 MPa 1/2 ; (h) water (i) a non-volatile strong acid, and (j) a salt thereof.
Abstract:
The wet process phosphoric acid evaporation, its clarifying, fertilizer production and fertilizer efficiency is improved in the presence of multi-component mixture of anionic surfactants and ammonium compound.
Abstract:
The present disclosure provides improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an ionic polymeric flocculating agent is added to a phosphoric acid containing composition subsequent to the addition of an organothiophosphorous heavy metal precipitating agent to said composition, particularly under gentle mixing conditions, such as between 100 and 300 rpm. The flocculating agent promotes the formation of agglomerates of the heavy metal containing precipitate, thus facilitating their removal from the composition. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.
Abstract:
A method of purifying phosphoric acid solution produced in wet process using nanofiltration. The claimed method contains the following : (a) providing wet phosphoric feed (b) subjecting the said feed to a first nanofilter (c) produce sulfate solids (d) removing the solids (e) subjecting a second nanofilter.
Abstract:
Die Erfindung betrifft ein Verfahren zur Rezyklierung von Phosphorsäurelösung aus einem Dekontaminationsbad (4), die durch radioaktive Anteile verschmutzt ist, wobei die verbrauchte Phosphorsäurelösung mit wäßriger Oxalsäurelösung verdünnt wird, um dabei Eisenoxalat abzutrennen und die Phosphorsäurelösung zur Dekontamination weiterer Anlagenteile eingesetzt wird, wobei der Eisenionengehalt in der Phosphorsäure (3b) im Dekontaminationsbad (4) kontinuierlich gemessen wird und dem Dekontaminationsbad (4) kontinuierlich Phosphorsäure (3b) entnommen und durch konzentrierte und gereinigte Phosphorsäure (3a) ersetzt wird, so daß eine bestimmte Konzentration von gelöstem Eisen im Kontaminationsbad (4) nicht überschritten wird, sowie eine Anlage zur Durchführung des Verfahrens. Die Lösung hat den Vorteil, daß in einer Anlage zur Rezyklierung einer Phosphorsäurelösung aus einem Dekontaminationsbad nur kleine Mengen der Phosphorsäurelösung im Umlauf sind, wobei das benötigte Arbeitsvolumen in den Anlagetanks erheblich reduziert wird. Daraus resultierend ist es möglich, die Reinigung von Phosphorsäurelösung von Eisen(ll)lonen aus der elektrochemischen Dekontamination mit mobilen Anlagen vorzunehmen.
Abstract:
Phosphorous ions are extracted (210) from solutions by adsorbing phosphorous ions in a scavenger and by releasing the phosphorous ions into an eluate during regeneration (230) of the scavenger. The regeneration (230) is performed by ammonia. Phosphate anions are precipitated (262) in form of tri-ammonium phosphate upon introduction (260) of excess amounts of ammonia. The ammonia remaining in solution after the precipitation of tri- ammonium phosphate is reused (266) for regenerating the scavenger.
Abstract:
The invention concerns a method for concentrating phosphoric acid consisting in precipitating a phosphoric acid salt with a precipitating agent in a solvent; separating in solid state the salt; melting a phosphoric acid salt derived from said precipitated salt, the thermal treatment comprising a salt which is that of a volatile compound with a melting point lower than that of phosphoric acid, and has a thermal decomposition temperature lower than the boiling point of phosphoric acid; thermal decomposition of the fused salt with evaporation of the volatile compound, and collecting non-evaporated concentrated phosphoric acid.
Abstract:
L'invention concerne un procédé de détermination de paramètres de mélange pour la préparation d'une solution d'acide phosphorique comprenant une teneur contrôlée en au moins un de ses constituants chimiques, dite solution à préparer, ladite solution à 5 préparer étant obtenue en mélangeant au moins deux solutions d'acide phosphorique, dites solutions à mélanger, présentant chacune une teneur différente en ledit constituant chimique, dont au moins une est un perméat résultant de la filtration d'une solution brute d'acide phosphorique au travers d'au moins une membrane de nanofiltration, ledit procédé étant caractérisé en ce qu'il comprend les étapes suivantes : 10 (1) la fourniture d'une teneur souhaitée (Tm) en ledit constituant chimique dans la solution d'acide phosphorique à préparer, et d'un volume souhaité (Vm) de ladite solution d'acide phosphorique à préparer, (2) la détermination, par un ordinateur, à partir de la teneur souhaitée (Tm) et du volume souhaité (Vm) : 15 - d'au moins une combinaison d'au moins deux solutions d'acide phosphorique parmi les solutions d'acide phosphorique à mélanger, - des volumes de chacune desdites solution d'acide phosphorique à mélanger de la combinaison, de sorte que le mélange des solutions d'acide phosphorique de la combinaison conduise 20 à la solution d'acide phosphorique à préparer.