Hoechst Aktiengesellschaft

Renate Adrian

Alexander Maurer

Horst-Dieter Wasel-Nielen

Gero Heymer

Raban Von Schenck

Thomas Staffel

Peter Wirtz

Herbert Panter

Bernd Cox

Gunther R Schimmel

Franz-Josef Dany

Joachim Kandler

Klaus Hestermann

Alexander Tapper

Karl Merkenich

Hermann Weber

Gerhard Kalteyer

Hedwig Prell

Horst Klassen

Gunter Sorbe

Dieter Nolker

Alexander Mauer

Klaus Somme

The present invention relates to a process for the production of crystalline sodium sheet silicate with kanemite structure with the chemical formula

Process for the production of crystalline sodium sheet silicate with

In order to remove ammonia from water vapor-containing gases, in particular offgases, the gases are brought into intimate contact with warmed polyphosphoric acid, the polyphosphoric acid advantageously having a P.sub.2 O.sub.5 content of from 70 to 84% by weight and a temperature of from 120.degree. to 170.degree. C.

Process for the removal of ammonia from gases

To prepare essentially water-insoluble, chain-form ammonium polyphosphate from equimolar amounts of di- ammonium phosphate and phosphorus pentoxide in the presence of ammonia at temperatures of from 170.degree. to 350.degree. C. with constant mixing, kneading and comminution, at least some of the diammonium phosphate and phosphorus pentoxide is replaced by partially ammoniated polyphosphoric acid. A plant for carrying out this process can comprise a sealed reactor (1) which is provided with metering devices (2, 3) and feed tubes (4, 5) for phosphorus pentoxide and diammonium orthophosphate, an ammonia feed tube (8), an ammonium polyphosphate discharge tube (9) and a line for offgas. Rotatable mixing, kneading and comminution elements are provided inside the reactor (1). Furthermore, a heatable stirred tank (11) which can be charged with polyphosphoric acid via a feed line (13) is provided and can be used to remore water vapor and ammonia from the offgas flowing from the reactor (1) via the line (20) and from which partially ammoniated polyphosphoric acid can be introduced into the reactor (1) via an outlet line (17).

Process for the preparation of ammonium polyphosphate

A process for producing essentially water-insoluble, chain-type ammonium polyphosphates of the general formula (NH.sub.4 PO.sub.3).sub.n, in which n is a number from 10 to 1,000, whose 20% by weight aqueous suspension prepared at 60.degree. C. has a viscosity of less than 100 mPa.s at 20.degree. C., is indicated, which comprises allowing a reaction mixture of ammonium orthophosphate and phosphorus pentoxide to react fully at a high mixing intensity in a crumbly phase at a temperature from 100.degree. to 300.degree. C. over a period of from 10 to 60 minutes and then heat-treating the reaction material in a known manner over a period of from 50 to 200 minutes at a temperature from 200.degree. to 300.degree. C. under an ammonia atmosphere. Advantageously, the reaction is carried out in a kneader.

Process for producing ammonium polyphosphate which gives a low-viscosity

Tooth pastes contain a cleaning agent consisting of dicalcium phosphate-dihydrate. The cleaning agent has an adsorptive power of more than 60 g H.sub.2 /100 g. Disclosed is the cleaning agent and a process for making it.

Tooth pastes, cleaning agent for tooth pastes based on dicalcium

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 relates to an abrasion-resistant storable cogranulate consisting of particles with a size of about 0.2 to 2 mm and having an apparent density of 800 to 1100 g/liter, the cogranulate containing

Cogranulate of alkali metal silicate and alkali metal polyphosphate, and

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 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

Pure Maddrell salt is produced by heating sodium phosphate to temperatures of 250.degree. to 420.degree. C. The sodium phospate used as starting material is sodium trimetaphosphate or a mixture of sodium trimetaphosphate with Maddrell salt, monosodium orthophosphate or disodium pyrophosphate, the mixture containing Na and P in a molar ratio of 1:1. Prior to heating the starting material, it is admixed with 0.5 to 5 weight% of orthophosphoric acid, polyphosphoric acid, phosphorus pentoxide or at least one salt of a volatile base forming polyphosphoric acid at the temperatures specified. The resulting mixture is calcined over the period necessary to transform the starting material to Maddrell salt.

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Hurth, Germany

Renate Adrian