Hoechst Aktiengesellschaft

Messer Griesheim Gmbh

Josef Cremer

Josef Holz

Hans Haas

Ortwin Leitzke

Erhard Albrecht

Friedrich Schulte

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 ozone content of ozone-containing gas mixtures is determined in a process wherein the ozone is converted to oxygen and which includes channeling a gas mixture containing nitrogen oxides and possibly water vapor through an adsorbent of aluminosilicate which contains 2 to 20% by weight of aluminum oxide and the aluminosilicate is of spherical shape with a particle diameter of 2 to 5 mm and a specific area of 200 to 650 m.sup.2 /g and an average pore diameter of 5 to 10 nm.

Process for determining the ozone content of ozone-containing gas

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Hurth, Germany

Josef Cremer