Process of producing magnesia with sulfuric acid recycle

US4096235A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Harry Edward Cross · Johannesburg, ZA
• Wolfgang Krieger
• Eberhard Anschutz
• Lothar Reh · Zumikon, CH
• Martin Hirsch · Friedrichsdorf, DE

Key dates

• Filing date: Oct 13, 1976
• Grant date: Jun 20, 1978
• Expiry date: Oct 13, 1996

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01F5/40
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

This invention relates to a process of producing magnesia from magnesium-containing carbonate ores, which comprises leaching with sulfuric acid, subsequently neutralizing the solution with magnesia, separating the undissolved impurities, crystallizing magnesium sulfate under pressure and above 150.degree. C so the crystals have from 1.5 to 4 moles of water per magnesium sulfate molecule and thermally decomposing the latter to form magnesia and SO.sub.2, recovering sulfuric acid from the sulfur dioxide produced in the decomposing steps and recycling the sulfuric acid to the leaching stage.