Process for the production of sodium perborate

US3985862A · kind A · utility

Assignee

• Deutsche Gold- und Silber-Scheideanstalt Vormals Roessler

Inventors

• Gerd Knippschild · Bad Nauheim, DE
• Hubert Schuster · Rheinfelden (Baden), DE

Key dates

• Filing date: Jun 6, 1975
• Grant date: Oct 12, 1976
• Expiry date: Jun 6, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B15/12
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Abrasion resistant and coarser sodium perborate tetrahydrate is prepared by reacting an aqueous sodium metaborate solution with aqueous hydrogen peroxide while avoiding free active oxygen and free alkali in the reaction medium. A strongly supersaturated perborate tetrahydrate solution having 200 to 700 grams/liter of perborate tetrahydrate is introduced into a previously prepared suspension of mother liquor and innoculant crystals which contains 100 to 500 grams/liter of suspension of seed crystals at such a rate that not more than 30 grams of perborate tetrahydrate grow as crystals per minute per square meter apparent innoculant surface area at 20 to 40.degree. C. and a rate of crystallization growth of not more than 100% whereupon the temperature is reduced to 15.degree. C. within 15 to 30 minutes, in a given case in a subsequent step. In another aspect of the invention the perborate is added at a point not earlier than the crystallizer.