Preparation of iron (iii) oxide pigment
AssigneeLANXESS Deutschland GmbH
InventorsWALDEMAR CZAPLIK, GUIDO KETTELER, JURGEN KISCHKEWITZ
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Abstract
The present invention relates to an improved process for producing iron oxide red pigments by the Penniman process using nitrate (also referred to as nitrate process or direct red process).
Claims19
A process for producing haematite pigments, the process comprising contacting iron, an aqueous haematite nucleus suspension containing haematite nuclei which have a particle size of 100 nm or less and a specific BET surface area of 40 m2/g to 150 m2/g (measured in accordance with DIN 66131), and an iron(II) nitrate solution in the presence of at least one oxygen-containing gas at temperatures of 70 to 99° C. to produce a suspension comprising haematite pigment.
The process according to claim, wherein the hydraulic mixing is carried out in a reactor having at least one inlet and at least one outlet for the reaction mixture in such a way that the flow velocity at the inlet of the reactor is at least 0.05 m/s, preferably at least 0.06 m/s.
Dependencies are inferred from the claim text.