Patent ID: 6508877
Filing Date: 2003-01-21
Classification: B82Y,C01G,C01P,C09C

Abstract:
A process for the production of aluminum-containing iron oxide crystallization nuclei having an &agr;-FeOOH crystal structure with an aspect ratio of 2100 to 3100 by using FeCl2, comprising the steps ofa) initially adding an Al component, while stirring, in amounts of 6 to 20 mole % based on total Fe, to an iron II chloride solution with a total Fe content of 20-100 g/l, and a Fe III content of 0.1-10 mole % Fe III (based on total Fe), b) heating this mixture to a precipitation temperature between 30Â° C. and 60Â° C., c) adding a precipitating agent with an active constituent content of 2-10 equivalents per liter to the mixture, and the molar ratio Fe+Al to precipitating agent is 20%-80% of the stoichiometric amount, d) then oxidizing the precipitated suspension with an oxidizing agent at an oxidation rate of 2-50 mole %/hr. of the iron to be oxidized.