Hoechst Aktiengesellschaft

Alexander Maurer

Renate Adrian

Gero Heymer

Horst-Dieter Wasel-Nielen

Joachim Kandler

Klaus Hestermann

Klaus Schrodter

Herbert Panter

Horst Staendeke

Jurgen Stenzel

Gerhard Mietens

Karl Merkenich

Raban Von Schenck

Markus Erpenbach

Gunter Sorbe

Dieter Nolker

Herbert Beumling

The disclosure provides a process for making mixed granulates from water-soluble condensed phosphates and at least one builder salt by subjecting the components making the granulate to granulation in the presence of water. To this end, the disclosure provides:

Process for making mixed granulates from condensed phosphates and

The disclosure provides activated ammonium polyphosphate undergoing decomposition at an increased rate at temperatures within the range 300.degree. to 600.degree. C., the ammonium polyphosphate having been obtained by reacting it with melamine and/or dicyandiamide or their derivatives at 100.degree. to 200.degree. C.

Activated ammonium polyphosphate, a process for making it, and its use

The disclosure relates to a process for making linear, substantially water-insoluble ammonium polyphosphates of the general formula (NH.sub.4 PO.sub.3).sub.10-1000 by heating and continuously mixing phosphorus pentoxide and ammonium orthophosphate in the presence of ammonia and tempering the resulting reaction product over a period of several hours at 200.degree. to 400.degree. C. in the presence of ammonia. To this end, the phosphorus pentoxide and ammonium orthophosphate are subjected at 50.degree. to 150.degree. C. to the following successive operations which provide

Linear, substantially water-insoluble ammonium polyphosphates and

The disclosure relates to a process for the continuous dearsenification of polyphosphoric acid with the aid of hydrogen sulfide in a gas admission zone. To this end, the disclosure provides for the acid to be dearsenified in a gas admission zone subdivided so as to comprise at least two separate liquid matter-receiving zones, each zone being separated from the other by means of a separate gas zone; for the liquid in each of the liquid matter-receiving zones to be maintained at a level 0.1 up to 10 cm high, without admission of gas; for hydrogen sulfide which remained unreacted in the individual liquid matter-receiving zones to be collected in the respective gas zone and for it to be finely redispersed in the liquid matter-receiving zone directly upstream of the respective gas zone by allowing the hydrogen sulfide to flow through a plurality of openings into the acid, the latter being delivered from the respective liquid-matter-receiving zone into the next downstream liquid-matter-receiving zone, and introduced thereinto directly below the liquid matter level therein; for precipitated arsenic sulfide to be separated from the acid coming from the lower end of the gas admission zone, and for the filtrate obtained to be freed from gaseous hydrogen sulfide in excess.

Process for the dearsenification of polyphosphoric acid

The invention relates to a process for making long chain ammonium polyphosphate consisting essentially of crystalline modification II. To this end, a mixture of phosphorus pentoxide and ammonium orthophosphate in a molar ratio of 1:0.9 to 1:1.1 is reacted with 0.1 to 15 mol % of melamine or its condensation products selected from melam, melem or mellon, calculated as melamine, at a temperature within the range 50.degree. to 150.degree. C. in the presence of an excess of ammonia and the reaction product is heat-treated at temperatures within the range 200.degree. to 400.degree. C.

Process for making long-chain ammonium polyphosphate

The invention relates to a process for converting water-soluble, condensed phosphates of the following general formula (I)

Process for making granulated condensed phosphates

The invention relates to a process for making granulated, partially or completely hydrated alkali metal diphosphates or triphosphates. To this end, the invention provides for alkali metal diphosphates or triphosphates which consist to an extent of at least 20% of particles with a size of less than 0.045 mm and are hydrated to an extent of less than 90%, based on the phosphates' theoretical content of water of hydration, to be intensively mixed and granulated in the presence of water and an ammonium polyphosphate, this latter being used in a proportion of about 0.5 to 50 weight %, based on the quantity of water used.

Production of granular alkali metal diphosphates or triphosphates

The disclosure relates to a granulate with a particle size essentially of about 0.2 to 2 mm consisting of

Granulate of alkali metal aluminum silicate and pentasodium

The disclosure relates to a process for making granulated, hydrated alkali metal orthophosphates. To this end, the disclosure provides for one or more anhydrous or partially hydrated alkali metal orthophosphates presenting a degree of hydration of less than 90%, based on the theoretically possible degree of hydration, and containing an at least 20% proportion of particles with a size of less than 0.045 mm, to be intensively mixed and granulated with water and an ammonium polyphosphate.

Process for making granulated alkali metal orthophosphates

The invention relates to a process for making a finely dispersed, sparingly soluble salt of an oxyacid of phosphorus, having a maximum particle size of 20 .mu.m, by reacting a compound of a divalent metal with the oxyacid of phosphorus or an alkali metal or ammonium salt thereof. More particularly, finely dispersed salt consisting to an extent of at least 90% of particles with a size between 0.05 and 7 .mu.m is made. To this end, an at least 5% by weight aqueous solution or suspension of a compound of a divalent metal selected from the group Mg, Ca, Sr, Ba, Mn, Zn, Cu, Cd, Pb, Sn, Co and Ni is reacted, while maintaining a pH range of between 3 and 9 and while stirring, with an at least 2 mol % solution of at least one trivalent metal selected from the group Al, Fe and Cr in the oxyacid of phosphorus and, optionally, with an aqueous solution of an alkali metal or ammonium salt of the oxyacid of phosphorus, and the precipitated salt is separated off and dried.

Process for the manufacture of finely dispersed sparingly soluble salts

The invention relates to a corrosion-inhibiting active pigment for use in the surface protection of iron and iron alloys. The pigment consists of a mixture of calcium hydrogen phosphate dihydrate, magnesium hydrogen phosphate trihydrate and zinc oxide. More specifically, the mixture contains 2 to 98 weight % of ZnO and 98 to 2 weight % of phosphate components. These in turn contain 3 to 97 weight % of CaHPO.sub.4 .multidot.2 H.sub.2 O and 97 to 3 weight % of MgHPO.sub.4 .multidot.3 H.sub.2 O. The active pigment is suitable for use in painting compositions or lacquers.

Corrosion-inhibiting pigment and paint composition

The invention relates to the production of phosphorus-containing anticorrosive pigments with a particle size of at most 20 microns by reacting one or more calcium or magnesium compounds with phosphoric acid or acid alkali metal or ammonium phosphates by intimately mixing an aqueous suspension or solution of the reactants inside a dispersing means rotating at a speed of 3000 to 10,000 rpm. More particularly, fine pulverulent calcium and magnesium compounds are converted, with agitation, together with water and, if desired, a water-soluble alkanol to a homogeneous suspension or solution. The suspension or solution is intimately mixed, inside the dispersing means at 0.degree. to 40.degree. C. and in an approximately stoichiometric ratio, with the phosphoric acid or acid phosphate solution. Resulting and precipitated pigment is separated and dried under mild conditions while maintaining its content of water of crystallization. The anticorrosive pigment is comprised of a homogeneous mixture and/or mixed crystals of which 10 to 95 mol % is calcium hydrogen phosphate dihydrate, the balance being magnesium hydrogen phosphate trihydrate. An at least 55 weight % proportion consists of particles with a size of up to 5 microns with a BET-surface of at least 1 m.sup.2 /g.

Production of an anticorrosive pigment on phosphate basis

The invention relates to a process for making phosphorus-containing anticorrosive pigments having a size of at most 20 microns by reacting one or more compounds of magnesium, calcium, strontium, barium, zinc, aluminum, iron, chromium or manganese with an oxygen acid of phosphorus or its alkali metal or ammonium salts at temperatures within the range 10.degree. to 100.degree. C. More particularly pigments consisting to an extent of at least 90% of particles with a size between 0.05 and 8 microns are produced by introducing an aqueous suspension or solution of the reactants into a dispersing means rotating at a speed of 3000 to 10,000 rpm, reacting the reactants by intimately mixing them, and separating and drying precipitated pigment.

Production of anticorrosive pigments containing phosphorus

The invention relates to a process for freeing aqueous phosphoric acid solutions from organic contaminants. To this end, the solutions are admixed and reacted with hydrogen peroxide in the presence of a catalyst consisting of a noble metal or metal oxide being inert with respect to phosphoric acid or of a mixture of said noble metal and metal oxide.

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Hurth, Germany

Alexander Maurer