Provided is a method of recovering phosphoric acid from a fermentation broth or a waste liquid thereof and reusing the recovered phosphoric acid in fermentation.

A method of recovering phosphoric acid from process water includes directing a process water stream having a pH and a first concentration of phosphoric acid and at least one salt into a vessel, contacting the process water stream with a sorption agent in the vessel, the sorption agent adsorbing phosphoric acid from the process water, withdrawing a first effluent including a first concentration of the at least one salt and a second concentration of phosphoric acid from the vessel, and contacting the sorption agent including the phosphoric acid with water, at least a portion of the phosphoric acid desorbing from the ion exchange media into the water to form a second effluent having a third concentration of phosphoric acid.

A method of recovering phosphoric acid from process water includes directing a process water stream having a pH and a first concentration of phosphoric acid and at least one salt into a vessel, contacting the process water stream with a sorption agent in the vessel, the sorption agent adsorbing phosphoric acid from the process water, withdrawing a first effluent including a first concentration of the at least one salt and a second concentration of phosphoric acid from the vessel, and contacting the sorption agent including the phosphoric acid with water, at least a portion of the phosphoric acid desorbing from the ion exchange media into the water to form a second effluent having a third concentration of phosphoric acid.

A method of recovering phosphoric acid from process water includes directing a process water stream having a pH and a first concentration of phosphoric acid and at least one salt into a vessel, contacting the process water stream with a sorption agent in the vessel, the sorption agent adsorbing phosphoric acid from the process water, withdrawing a first effluent including a first concentration of the at least one salt and a second concentration of phosphoric acid from the vessel, and contacting the sorption agent including the phosphoric acid with water, at least a portion of the phosphoric acid desorbing from the ion exchange media into the water to form a second effluent having a third concentration of phosphoric acid.

A method of recovering phosphoric acid from process water includes directing a process water stream having a pH and a first concentration of phosphoric acid and at least one salt into a vessel, contacting the process water stream with a sorption agent in the vessel, the sorption agent adsorbing phosphoric acid from the process water, withdrawing a first effluent including a first concentration of the at least one salt and a second concentration of phosphoric acid from the vessel, and contacting the sorption agent including the phosphoric acid with water, at least a portion of the phosphoric acid desorbing from the ion exchange media into the water to form a second effluent having a third concentration of phosphoric acid.

Disclosed herein are compositions and methods of mitigating scale in phosphoric acid and ammonium phosphate plants. Scale-mitigating compositions of the invention can be added to phosphoric acid before or during the concentration in the evaporator cycle of a phosphoric acid plant. The compositions retard the formation of scale on surfaces in contact with the phosphoric acid, and thus time between cleaning is extended and plant productivity increased. Further, the scale that forms is softer and more easily cleaned from surfaces, reducing non-operation time of the plant and/or evaporator. Methods of mitigating scale formation in phosphoric acid production and phosphoric acid handling plants are disclosed. In the methods, scales accumulate more slowly and are softer, more tractable, and more easily cleaned from surfaces to which they adhere.

Disclosed herein are compositions and methods of mitigating scale in phosphoric acid and ammonium phosphate plants. Scale-mitigating compositions of the invention can be added to phosphoric acid before or during the concentration in the evaporator cycle of a phosphoric acid plant. The compositions retard the formation of scale on surfaces in contact with the phosphoric acid, and thus time between cleaning is extended and plant productivity increased. Further, the scale that forms is softer and more easily cleaned from surfaces, reducing non-operation time of the plant and/or evaporator. Methods of mitigating scale formation in phosphoric acid production and phosphoric acid handling plants are disclosed. In the methods, scales accumulate more slowly and are softer, more tractable, and more easily cleaned from surfaces to which they adhere.

The present invention relates to a method for purifying phosphoric acid from a mixture which comprises organic compounds and water. In particular the present invention relates to a method for purifying phosphoric acid from a pulping slurry, containing or consisting of phosphoric acid, one or more organic compounds and water, comprising or consisting of the following steps: i) providing a mixture containing or consisting of phosphoric acid, one or more substance(s) S having at least one secondary carbon atom attached to an alkoxy group, one or more (further) organic compounds and water, and adjusting (if necessary) the molar ratio of phosphoric acid to the total of one or more substance(s) S, having at least one secondary carbon atom attached to an alkoxy group, in the mixture to be in the range of from 1:0.4 to 1:10, preferably to be in the range of approximately 1:0.6 to 1:4, especially preferably to be approximately 1:0.85 to 1:2, ii) heating the mixture to 25 C. or more until phase separation occurs, iii) removing the light phase, and iv) separating the phosphoric acid from the heavy phase.

The present invention relates to a method for purifying phosphoric acid from a mixture which comprises organic compounds and water. In particular the present invention relates to a method for purifying phosphoric acid from a pulping slurry, containing or consisting of phosphoric acid, one or more organic compounds and water, comprising or consisting of the following steps: i) providing a mixture containing or consisting of phosphoric acid, one or more substance(s) S having at least one secondary carbon atom attached to an alkoxy group, one or more (further) organic compounds and water, and adjusting (if necessary) the molar ratio of phosphoric acid to the total of one or more substance(s) S, having at least one secondary carbon atom attached to an alkoxy group, in the mixture to be in the range of from 1:0.4 to 1:10, preferably to be in the range of approximately 1:0.6 to 1:4, especially preferably to be approximately 1:0.85 to 1:2, ii) heating the mixture to 25 C. or more until phase separation occurs, iii) removing the light phase, and iv) separating the phosphoric acid from the heavy phase.

The present invention provides a method for the production of a metal halide adduct of S.sub.4N.sub.4, in particular a specific copper adduct of S.sub.4N.sub.4, for the visualisation of a print on an object, in particular a fingerprint on a metal object. The present invention also provides a method and apparatus for visualising a print on an object, using S.sub.2N.sub.2 obtained from a metal halide adduct of S.sub.4N.sub.4.