Hoechst Aktiengesellschaft

Hans Haas

Werner Kowalski

Theo Dahmen

Markus Erpenbach

Johannes Krause

Gunther R Schimmel

Josef Holz

Herbert Ressel

Hans Scheffer

Ben Damman

Paul De Witte

Josef Cremer

Friedrich Schulte

Herbert Landgraber

Johan Scheffer

Helmut Klee

Alkali metal polyphosphates consisting substantially of hollow spheroidal particles with an apparent density of less than 350 g/l are made. To this end, an alkali metal orthophosphate solution is forced under a pressure of 6-40 bars into a fluidization zone; the orthophosphate solution is fluidized in the fluidization zone by injecting a finely dispersed permanent gas maintained under a pressure higher than the orthophosphate solution; and the fluidized orthophosphate solution is sprayed with the aid of a plurality of single medium nozzles arranged downstream of the fluidization zone through a flame zone produced inside the spray tower. Apparatus for carrying out the process.

Spheroidal alkali metal polyphosphates of low apparent density, and

A granular hydrated product consisting completely or partially of sodium triphosphate for use in detergent and cleaning compositions is made. To this end, pulverulent sodium triphosphate containing less than 22 wgt % water is compacted by initially mixing it with a quantity of water sufficient for hydrating at most 100% of the sodium triphosphate to the hexahydrate and then continuously admitting the resulting mixture to a zone inside which it is made into solid matter under pressure.

Process for making a granular product containing sodium triphosphate

Hexagonal phosphorus pentoxide of diminished reactivity is made by burning liquid yellow phosphorus with a mixture of dry air and pure oxygen inside a combustion zone with the resulting formation of a gas stream containing phosphorus pentoxide; next, the gas stream coming from the combustion zone is passed initially through an intermediary zone indirectly cooled by means of fluidized matter and then through a condensing zone fitted with an immersion tube indirectly cooled by means of fluidized matter; the gas stream is passed through the immersion tube at a mean temperature of 450.degree. to 600.degree. C. and allowed to remain in the immersion tube over a period of 2 to 5 seconds.

Process for making phosphorus pentoxide of diminished reactivity

Alkali metal polyphosphates consisting substantially of hollow spheroidal particles with an apparent density of less than 350 g/l are made. To this end, an alkali metal orthophosphate solution is forced under a pressure of 6-40 bars into a fluidization zone; the orthophosphate solution is fluidized in the fluidization zone by injecting a finely dispersed permanent gas maintained under a pressure higher than the orthophosphate solution; and the fluidized orthophosphate solution is sprayed with the aid of a plurality of single medium nozzles arranged downstream of the fluidization zone through a flame zone peoduced inside the spray tower. Apparatus for carrying out the process.

Alkali metal polyphosphates consisting substantially of hollow spheroidal particles with an apparent density of less than 320 g/l are made. To this end, an aqueous alkali metal orthophosphate solution and an aqueous solution of an inflating agent are simultaneously forced under a pressure of 6-40 bars into a fluidization zone; the two solutions are fluidized in the fluidization zone by injecting a finely dispersed permanent gas maintained under a pressure higher than the two solutions and the fluidized solutions are sprayed with the aid of a plurality of single medium nozzles arranged downstream of the fluidization zone through a flame zone produced inside the spray tower. Apparatus for carrying out the process.

Iron and vanadium is phosphoric acid solution are reduced. To this end, the phosphoric acid solution is contacted with ferrophosphorus which is used as the reductant.

Process for reducing iron and vanadium in phosphoric acid solution

The disclosure relates to a process for making alkali metal polyphosphates, especially alkali metal triphosphates. To this end, the disclosure provides for an alkali metal phosphate solution or suspension to be forced through at least one nozzle and for them to be sprayed inside a spray tower through a flame zone produced by a one or more burners arranged in annular fashion. More particularly, the disclosure provides for fine particulate alkali metal polyphosphates, especially alkali metal triphosphates, to be additionally introduced into the spray tower from above and for them to be regularly distributed across the spray region(s) of the nozzle(s) with formation of agglomerated products. The disclosure also relates to an apparatus for carrying out the process. The apparatus is comprised of a cylindrical spray tower (1) having a tapered lower end (3) and being closed by means of a cover (2); a spray means (6) being passed centrally through the cover (2); a plurality of burners (11) and a solid matter feed means being passed through the cover concentrically with respect to the spray means (6) and so as to be spaced therefrom; and a bevelled issuing gas outlet (4) opening upwardly from the tapered end of the spray tower (1).

Process for making alkali metal polyphosphates

The disclosure relates to a process for making calciummonohydrogen phosphate dihydrate with a high degree of whiteness from pure phosphoric acid and naturally occurring calcium carbonates. More particularly, a fine-particulate calcium carbonate is suspended in water and the suspension is mixed at temperatures between 0.degree. and 60.degree. C. with phosphoric acid so as to establish a Ca/P-ratio of 0.20 up to 0.57. The phosphoric acid is added in quantities per unit time preventing the resulting mixture from foaming over. Next, solid matter constituents are separated from the mixture, after CO.sub.2 has ceased to evolve, with the resultant formation of a clear colorless acid solution. This solution and an aqueous suspension or solution of pure alkali metal and/or alkaline earth metal carbonates and/or hydroxides, are jointly introduced into a reaction zone at a reaction temperature of 20.degree. to 45.degree. C. so as to establish a pH-value initially of 2.0 to 5.0 and then, towards the end of the reaction of 6.0 to 8.0. Finally, the reaction product is filtered off, washed out, and dried in known fashion.

Process for making calciummonohydrogen phosphate dihydrate

The disclosure relates to sodium tripolyphosphate containing up to 95 weight % phase-I, 0.1 to 22 weight % water of crystallization and 0.01 to 2.0 weight %, calculated as metal, of a compound of the metals selected from calcium, magnesium, zinc or strontium, the compound yielding ions in an aqueous medium. The disclosure also relates to a process for making the tripolyphosphate, and to its uses.

Sodium tripolyphosphate, process for making it, and its use

The disclosure relates to a process for making granular sodium tripolyphosphate of high abrasion resistance. To this end, the disclosure provides for sodium orthophosphate to be subjected to a one-stage spray-drying operation inside a heated spray tower by means of a nozzle with condensation of the orthophosphate. More particularly the orthophosphate is sprayed jointly with a solution of a high molecular weight phosphate of sodium, potassium or ammonium.

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Swisttal, Germany

Hans Haas