Toyo Soda Manufacturing Co., Ltd.

Yoichi Hiraga

Mitsuo Kikuchi

Tsugio Murakami

Osamu Watanabe

Masaki Nakatani

Kazushige Igawa

Hiroyuki Saito

Osamu Fujii

A method for removing organic materials from a wet process phosphoric acid obtained by treating an uncalcined phosphate rock with sulfuric acid. The wet process phosphoric acid is contacted with a reducing material having a standard single electrode potential of at most 1.42 V and then further contacted with active carbon.

Method for removing organic materials from a wet process phosphoric acid

Ethyleneamines are efficiently recovered from an aqueous solution thereof by extracting them from the aqueous solution into an organic phase with an extractant selected from carbonyl group-containing organic solvents, benzyl alcohol, carboxylic acids and salts thereof, alkylphosphoric acids and salts thereof, and mixed solvents containing at least one of these extractants. The ethyleneamines in the organic phase is recovered preferably from the organic phase to the aqueous phase by incorporating an acid therein, followed by phase separation.

Process for recovering ethyleneamines

A method for solvent extraction of phosphoric acid comprises counter-currently contacting an impure phosphoric acid solution containing at least 45 wt. % of P.sub.2 O.sub.5 with a partially water-miscible solvent in the presence of sulfuric acid, and which is characterized in that

Solvent extraction method of phosphoric acid

A stable calcium hypochlorite composition and a method for the preparation thereof. The composition has a calcium hypochlorite anhydride and/or a calcium hypochlorite dihydrate used as main constituent and comprises at least 60 wt % of calcium hypochlorite; at least 5 wt % of calcium hydroxide; at least 4 wt % of water content; and 5 wt % or less of than that calcium chloride. The composition is stable and decomposes only in a less degree at a high temperature and during storage over a long period.

Stable calcium hypochlorite composition and method for manufacture

A wet process phosphoric acid obtained by an solvent extraction method with n-butanol and/or isobutanol comprises

Purification of wet process phosphoric acid

Wet process phosphoric acid prepared by treating phosphate rock with sulfuric acid is purified by extracting said wet process phosphoric acid with an organic solvent containing an equilibrium concentration of phosphoric acid in a first extraction section such that substantial extraction of phosphoric acid from said wet process phosphoric acid is prevented while the organic impurities in said wet process phosphoric acid are substantially extracted and under conditions which prohibit significant extraction of iron impurities into said solvent extractant, extracting the extracted wet process phosphoric acid of reduced organic impurity content with an organic solvent in a second extraction section, returning a portion of the solvent from the second extraction section to the solvent extraction phase of the first section, removing the organic impurities from the solvent phase which is obtained from the first extraction section, and returning at least a portion of the solvent from which the organic impurities have been removed to said second extraction section.

Purification of phosphoric acid

A method of purifying extracted phosphoric acid containing substantially no metallic impurities which comprises:

Process for removing dissolved silica from extracted phosphoric acid

Wet process phosphoric acid prepared by treating phosphate rock with sulfuric acid and separating calcium sulfate, is purified to obtain a purified phosphoric acid by (a) an acid extracting section contacting the wet process phosphoric acid and a phosphoric acid solution containing impurities obtained in the scrubbing section with an organic solvent in the presence of the hydrochloric acid required for extracting a substantial amount of the phosphoric acid component; (b) a scrubbing section contacting the extract obtained in the acid extracting section with aqueous phosphoric acid or water while maintaining the chloride ion concentration in the aqueous phase in the range of 20 to 40 g/liter as Cl; (c) an acid stripping section contacting the purified extract obtained in the scrubbing section with water and (d) an adsorbing section contacting the extracted phosphoric acid obtained in the acid stripping section with an anion-exchange resin.

Phosphoric acid purification

A process for removing sulfate ions from extracted phosphoric acid which is substantially free of metallic ion impurities and which has been prepared by extracting wet process phosphoric acid with an organic solvent which comprises: A. adjusting the extracted phosphoric acid concentration to a concentration greater than 70%; B. adding an amount of a barium compound which is less than the stoichiometric equivalent amount of barium relative to the amount of dissolved sulfate ion to form barium sulfate crystals; and C. separating said barium sulfate from the resulting slurry at a temperature less than 80.degree. C and recovering purified, extracted phosphoric acid; Wherein the amount of barium compound added is such that said purified extracted phosphoric acid contains at least 5 ppm of sulfate ions.

Process for removing sulfate ions from extracted phosphoric acid with a

A process for removing organic material from extracted phosphoric acid comprises contacting extracted phosphoric acid with a chlorate and hydrochloric acid at a temperature higher than 100.degree. C while maintaining the concentration of the extracted phosphoric acid at a value higher than 90 wt% as H.sub.3 PO.sub.4. Hydrochloric acid may also be included with the chlorate.

Process for removing organic material from wet process phosphoric acid

A process for removing sulfate ions from extracted phosphoric acid which is substantially free of metallic ion contaminants, which comprises adding less than the stoichiometric equivalent of a barium compound relative to the amount of dissolved sulfate ion to said extracted phosphoric acid to form barium sulfate crystals, adding active carbon to the resulting slurry, separating the solid components from the slurry and recovering purified phosphoric acid.

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Shinnanyo, Japan

Yoichi Hiraga