Bayer Aktiengesellschaft

Hans Kyri

Heinrich Heine

Karl Brandle

Siegfried Schneider

Jurgen Dobbers

Martin Muller

Hans-Dietrich Lauss

A precipitating agent for the dephosphatization of effluent comprising by weight about 5 to 75% of active iron (III) sulphate, about 25 to 95% of active iron (III) oxide and 0 to about 10% of anhydrous magnesium sulphate. Optionally, an alkaline constituent such as the oxide or hydroxide of calcium or magnesium may also be present and dephosphatization is effected at a pH of about 4.5 to about 8.5. Extremely low contents of residual phosphorous can be obtained in the filtrate, a precipitate containing iron and phosphorous settling out cleanly.

Precipitating agent for dephosphatizing effluent

In the purification of an ammonium fluoride solution containing silicic acid by adding iron (III) ions and precipitating the iron (III) ions at a pH above 8.5 and a concentration of free ammonia in the solution of more than about 1% by weight, the silicic acid being carried with the iron (III) ion precipitate, the improvement which comprises adding the iron (III) ions to the ammonium fluoride solution at a temperature below about 30.degree. C. and, before removal of the precipitate, to the solution a salt of at least one of the alkali metals, alkaline earth metals, zinc, aluminum and lead in such quantity that the solution becomes saturated with such salt.

Purification of ammonium fluoride solutions

In the production of a gypsum-based porous body of high strength by foaming a gypsum-water mixture, the improvement which comprises including in said mixture about 0.1 to 1 part of a water-soluble aluminum compound per 100 parts by weight of gypsum, calcium oxide or calcium hydroxide in such a quantity that the final mixture has a pH-value in the range of about 10 to 13, a decomposition catalyst, and about 0.5 to 5 parts of hydrogen peroxide, expressed as a 35% solution, per 100 parts by weight of mixture, the ratio of solids to liquid being about 1 : 0.4 - 1. The preferred aluminum compound is aluminum nitrate. The preferred decomposition catalysts are manganese compounds such as manganates or permanganates, e.g. potassium permanganate.

Growing community of inventors

Cologne, Germany

Hans Kyri