Process for preparing inorganic pigments of particular particle size
AssigneeBASF Lacke + Farben, AG
InventorsHarald Gaedcke, Guenter Etzrodt, Egon Liedek
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Abstract
Inorganic oxide pigments (ceramics) are prepared by mixing the starting materials in the presence of water and in the presence or absence of assistants, drying and subsequent calcining in a rotary furnace by processing the starting materials in the presence of water into a pumpable suspension having particle sizes of 50%<10 .mu.m and 100%<50 .mu.m, dewatering the suspension by spray drying it to leave porous granules, and calcining those granules>97% from 20 to 800 .mu.m in size.
Claims1
In a process for preparing inorganic oxide pigments by mixing starting materials in the presence of water and in the presence or absence of assistants;
- drying;
- subsequently calcining in a rotary furnace, with or without subsequent milling;
- and washing with or without drying of the calcined products, the improvement which consists essentially of:
- 1) dispersing or milling the starting materials in the presence of water to produce a pumpable aqueous suspension wherein the solids have particle sizes of 50%<10 .mu.m and 100%<50 .mu.m, the particle sizes being determined by a laser granulometer;
- 2) dewatering the produced suspension by spraying the suspension by means of a single-fluid pressure nozzle to produce porous granules which are made up of agglomerates of the particles produced in step 1);
- and
- 3) calcining those porous granules which are>97% from 20 to 800 .mu.m in size in a rotary furnace, the particle sizes of the porous granules being determined by sieve analysis.
Dependencies are inferred from the claim text.