公开(公告)号：DE2517713A1

公开(公告)日：1976-11-04

申请号：DE2517713

申请日：1975-04-22

Applicant: BASF AG

Inventor： OSTERTAG WERNER DR ,  WUNSCH GERT DR ,  EBENHOECH FRANZ DR ,  VOELKL ERFRIED DR ,  BOCK GUSTAV DR

IPC: C01G49/00 ,  C09C1/34

Abstract: Prodn. of a readily dispersing fine-grain, brown pigment having the formula: CrxFe2-xO3 (in which 0.1=x=1) is improved in that an aq. soln. of CrO3 (pref. concn. 45-63 wt.%) and/or gaseous CrO2Cl2 is introduced in the form of a spray into a reaction zone in presence of water vapour, gaseous Fe(CO)5 and O2; the reaction is carried out at a temp. >700 degrees C (pref. 700-1000 degrees C); and the resulting solid reaction product remains in the reaction zone for at least 1 sec. (pref. up to 10 sec.) before the withdrawal. These pigments are temp. resistant and light fast. Their prodn. is more convenient than the usual wet coprecipitation of the components, with subsequent sepn. and calcination. These are no- by-products, and high purity pigments are obtd. The colour can be easily controlled (increasing Cr content and, to a lesser extent, prolonged residence time give darker brown colouration.).