Process for puffing borax

Abstract

A rotary inclined tubular drier for puffing or expanding borax and a process for the production of puffed or expanded borax beads of desired physical characteristics. A rotatable tube is mounted on bearing wheels and surrounded by a fixed, close-fitting, insulated tube having electrical heating elements running lengthwise attached to its inside wall. The rotatable tube is fed continuously with granular borax feedstock by a vibratory feeder from its higher end and the puffed borax is discharged into a discharge chute from the lower end of the tube. A counter current of dry air is maintained by a suction hood at the high end of the tube, and borax is prevented from adhering to the interior of the tube by an adjustable, spring-loaded, internal scraper. The temperature of the drier is controlled by means of a pyrometer incorporated into a scraper support rod on the interior of the tube. Puffed borax beads of particularly desirable characteristics for detergent use are produced from sodium tetraborate pentahydrate by heating the drier to 220.degree.-450.degree.F and adjusting the angle of incline and rate of rotation so as to provide a 45-90 second residence time in the drier for the borax.

Dependencies are inferred from the claim text.