PRODUCTION OF ANHYDROUS, CRYSTALLINE BORON-OXIDE IN FLUIDIZED-BED REACTOR

Industrial production of boron oxide is via fusion of boric acid at 55 0-1000 degrees C. The glassy melt thus obtained is then cooled until s olid; crushed, ground and then sieved to allow classification accordin g to particle size and distribution. The melting of boric acid is both the most critical and costly stage of all these operations, because b oron oxide is highly corrosive to refractories and steel. Our study al lows the production of commercial quality anhydrous and crystalline bo ron oxide without the melting and other processes mentioned above. Thi s is achieved by dehydrating boric acid in a fluidized bed with a grad ual increase in the bed temperature up to 250 degrees C. During this p rocess as the bed temperature is increased gradually, particular atten tion is paid to keep the dehydration rate below a certain value to pre vent melting or sticking, and to secure the desired bulk density value of the product.