Patent · US Expired

Production of hematite pigments in the form of platelets

US5244649A · kind A · utility

28Cited by

7References

4Claims

0Family size

Assignee

BASF SE

Inventors

Werner Ostertag · Havelsee, DE
Christoph Schwidetzky · Ludwigshafen, DE
Norbert Mronga · Dossenheim, DE

Key dates

Filing date	Aug 23, 1990
Grant date	Sep 14, 1993
Priority date	—
Expiry date	Aug 23, 2010

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01P2006/62
WIPO fieldBasic materials chemistry
WIPO sectorChemistry

Abstract

Iron oxides in the form of platelets are produced by hydrothermal treatment of aqueous suspensions containing iron(III) hydroxide or oxide hydrates in the presence of alkali metal hydroxides and of aluminum and/or silicon compounds in two stages. The normality of the alkali is from 0 2 to 2 N in the first stage and is increased by from 0.2 to 2.5 in the second stage. The two-stage process according to the invention makes it possible to produce hematite pigments which are in the form of platelets, have increased luster, larger particle diameter, improved dispersibility and color hues which can be adjusted as desired.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.