Bk Ladenburg Gmbh

Bk Ladenburg Gmbh Gesellschaft Fuer Chemische Erzeugnisse

Hans-Georg Steinert

Alexander Maurer

Richard Taenzler

Guenter Raab

Gudrun Raab

Gerhard Schoenmann

Armin Etzel

The present invention provides a process and apparatus for the production of coarse-grained dicalcium phosphate anhydride, at least 95% of which consists of particles with a grain diameter of &gt;45 .mu.m, wherein, at a temperature of 60.degree. to 100.degree. C., a highly reactive calcium component, for example freshly slaked milk of lime or an aqueous slurry or suspension of calcium hydroxide and/or calcium carbonate, is introduced directly into the stirrer zones of a vessel containing aqueous phosphoric acid and having one or more turbulent stirrer zones. An equivalent amount of aqueous phosphoric acid is introduced into another zone of the vessel, the speed of introduction being so regulated that a pH value of 3.0 to 4.5 is obtained in the stirrer zone and the whole batch or a continuously or semi-continuously removed part thereof is cooled to 40.degree. to 60.degree. C. The removed part then is mixed with an additional calcium component, for example milk of lime, to obtain a pH value of from 5.5 to 6.8, the mixture further stirred for 10 to 60 minutes and the resultant course-grained dicalcium phosphate anhydride is filtered off and dried.

Process for the production of coarse-grained, anhydrous calcium

An apparatus for the preparation of alkali metal monofluorophosphates is disclosed. The apparatus includes a melting crucible of a platinum/rhodium alloy, devices for feeding the alkali metal fluoride and alkali metal metaphosphate or alkali metal polyphosphate raw materials into the upper part of the crucible, an outflow orifice for molten alkali metal fluorophosphate in the bottom of the crucible, a corresponding discharge orifice in the furnace, and a cooling arrangement, wherein a direct voltage is applied between the cooling arrangement and the melting crucible which is connected as the anode.

Apparatus for the preparation of alkali metal monofluorhosphates

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Eschelbronn, Germany

Hans-Georg Steinert