Method for manufacturing alkali chromates from chromium ore

US5505918A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Uwe Arndt · Cologne, DE
• Michael Batz · Leichlingen, DE
• Rainer Bellinghausen · Neunburg vorm Wald, DE
• Hans-Dieter Block · Cologne, DE
• Heinrich Helker · Krefeld, DE
• Norbert Lonhoff · Leverkusen, DE
• Hans-Heinrich Moretto · Cologne, DE
• Hans-Georg Nieder-Vahrenholz · Pulheim, DE
• Hans Rinkes · Neunburg vorm Wald, DE
• Bernhard Spreckelmeyer · Johannesburg, ZA
• Rainer Weber · Leverkusen, DE

Key dates

• Filing date: Sep 28, 1994
• Grant date: Apr 9, 1996
• Expiry date: Sep 28, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01G37/14
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method for manufacturing alkali chromates by the reacting of chromium ore with alkali compounds and oxidation in an atmosphere containing at least 50% oxygen is described, in which the mixture consisting of chromium ore, alkali compound and optionally leaning materials is heated in a first stage in an atmosphere containing not more than 5 vol. % oxygen to a temperature between 1000.degree. and 1 400.degree. C., and in a second stage is oxidized at a lower temperature of 900.degree. to 1 070.degree. C. with supply of an atmosphere containing at least 50% oxygen.