Abstract: A method for recovery of salts comprises providing (210) of an initial aqueous solution comprising ions of Na, K, Cl and optionally Ca or a material which when brought in contact with water forms an initial aqueous solution comprising ions of Na, K, Cl and optionally Ca. The start material is treated (230) into an enriched aqueous solution having a concentration of CaCl2 of at least 15% by weight. The treatment (230) comprises at least one of reduction of water content and addition of Ca. The treatment (230) generates a solid mix of Na Cl and KCl. The solid mix of NaCl and KCl is separated (235) from the enriched aqueous solution, giving a depleted aqueous solution comprising ions of Ca and Cl as main dissolved substances. An arrangement for recovery of salts is also disclosed.

Abstract: A method for production of phosphate compounds comprises dissolving of a raw material comprising phosphorus, aluminium and iron, in a mineral acid. Insoluble residues from the dissolving step are separated. Iron hydroxide is added causing precipitation of phosphate compounds. The precipitated phosphate compounds are removed. The phosphate compounds are dissolved by an alkaline solution. Iron hydroxide is filtered out. Lime is added, causing precipitation of calcium phosphate. The precipitated calcium phosphate is separated. The leach solution after the separating of precipitated calcium phosphate is recycled to be used for dissolving phosphate compounds by an alkaline solution.

Abstract: A method for concentration of phosphate compounds comprises dissolving (205) of sludge ash in hydrochloric acid. Insoluble residues are separated (210), thereby forming a first leach solution. A mole ratio of phosphorus to a sum of ferric iron and aluminum in the first leach solution is controlled (215) to be larger than 1. A base is added (220) to the first leach solution in an amount causing precipitation of phosphate compounds. The precipitated phosphate compounds are removed (225) from the first leach solution. Sulphuric acid is added (240) to the first leach solution, causing precipitation of sulphate compounds. The precipitated sulphate compounds are separated (245) from the first leach solution. At least a part of the leach solution is recycled (248) as the hydrochloric acid used for the dissolving of sludge ash. Further methods for processing the precipitated phosphate compounds are presented as well as arrangements for performing the methods.

Abstract: An arrangement (100) for production of fully soluble, pure and well defined mono- or di-ammonium phosphates, comprises an extraction section (10), a stripping section (20) and end treatment arrangements (90). The extraction section performs a liquid-liquid extraction of phosphate between a feed liquid (1) comprising phosphoric acid and being essentially free from nitrate ions, and a solvent (5) having a solubility in water of less than 2%. The stripping section performs a liquid-liquid extraction of phosphate between solvent loaded with phosphate and a strip solution (4). The solvent depleted in phosphate is recirculated to the extraction section for further extraction of phosphate. The strip solution is an aqueous ammonium phosphate solution, wherein at least 80% of the ammonium phosphate is monoammonium phosphate and/or wherein the solvent is a water-immiscible alcohol.

Abstract: A method for production of ammonium phosphates includes providing (210) of a phosphorus-loaded water immiscible liquid phase, adding (212) of anhydrous ammonia to the water immiscible liquid phase, precipitating (214) of mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase and extracting (218) of the precipitated mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase. The method further includes controlling (216) of a temperature of the water immiscible liquid phase during the adding (212) and precipitating (214) to a predetermined temperature interval.

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: A method for production of ammonium phosphates includes providing (210) of a phosphorus-loaded water immiscible liquid phase, adding (212) of anhydrous ammonia to the water immiscible liquid phase, precipitating (214) of mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase and extracting (218) of the precipitated mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase. The method further includes controlling (216) of a temperature of the water immiscible liquid phase during the adding (212) and precipitating (214) to a predetermined temperature interval.

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.