US 4,968,500 A · Continuous method for preparation of granulated sodium perborate

Abstract

The spray drying of a solution containing hydrogen peroxide and sodium metaborate to obtain primary particles which are immediately conveyed after leaving the drying zone to a granulating device and are then granulated in the presence of free and/or perborate water of crystallization. The granulated materials are dried, if necessary. The generally amorphous primary particles are converted into granulated materials with at least partially crystalline structure and significantly improved shelf life. The work is performed with advantage in a spray dryer with integrated fluid bed or in a compressing granulating device. The method is suitable for preparing perborate granulated materials with over 10% by wt., especially perborate monohydrate granular materials with 14-16% by wt. active oxygen.

Claims15

Dependent claims

A continuous method for the preparation of granulated perborate with an Oa-content of 14 to 16% by weight comprising the steps of:

spraying an aqueous solution comprising hydrogen peroxide and sodium metaborate in a molar ratio of 0.9 to 1.1 into a drying zone to form droplets, wherein no nuclei of perborate are introduced into said drying zone, drying said droplets by means of a heated gas in said drying zone to thereby form powdery, essentially amorphous sodium perborate, conveying said powdery perborate after leaving said drying zone to a separate granulating zone, separated from said drying zone, adding water in sprayed form, vapor form, in the form of perborate containing water of crystallization or in the form of sodium perborate tetrahydrate to said powdery perborate and granulating by intimately bringing into contact said water and powdery perborate.

Dependencies are inferred from the claim text.

Continuous method for preparation of granulated sodium perborate

Life of this patent

Continuous method for preparation of granulated sodium perborate

Life of this patent

Abstract

Claims15