Production of Anhydrous, Crystalline Borax in a Fluidized Bed

Abstract

Industrial production of anhydrous borax is via fusion of borax deca- or pentahydrate at 800−1000 °C. The glassy melt obtained thus is then cooled to solidify, crushed, ground, and then sieved to be classified according to its particle size and distribution. Since molten borax is highly corrosive to refractories and steel, among all these operations, the melting of borax is the most critical and the most costly. Our study gives way to production of commercial quality anhydrous and crystalline borax by eliminating melting and other above-mentioned operations. For this purpose, borax pentahydrate is dehydrated in a fluidized bed with gradually increasing the bed temperature up to 550 °C. During this process, as the bed temperature is increased gradually, particular attention is paid to keep the dehydration rate below a certain value to secure the bulk density of the product at levels greater than 0.3 g/cm3.

Effect of Silanization Time on the Surface Modification of Anhydrous Borax

“…Borates are indispensable constituents of most industrial ceramic and glass products, offering both excellent glass-forming and fluxing properties [9,10]. Anhydrous borax (Na 2 B 4 O 7 ) produced via fusion of hydrated forms of borax at approximately 1000 °C [11] is preferred to other hydrous forms in high-temperature applications since it does not cause any foaming problems arising from dehydration of the water [10]. However, anhydrite form of borax is water-soluble due to its inherent properties like the hydrated forms.…”

Characterization of surface properties of dry-coated anhydrous borax powders

“…Anhydrous borax (Na 2 B 4 O 7 ), which is produced via fusion of borax deca-or pentahydrate at approximately 1000 °C, is an indispensable boron-containing compound of most industrial ceramic and glass products, offering both excellent glass-forming and fluxing properties [1][2][3]. The anhydride form of borax is preferred to other hydrous types since it has a slower and lower solubility than its aqueous forms, and it does not cause any foaming problems arising from water dehydration in high-temperature applications [2].…”

The Effect of Surface-Treated Anhydrous Borax Additions on Hard Porcelain Properties

“…Boron oxide-bearing minerals can technologically be considered as important alternative raw materials since they have a glass-forming character and have been used in the ceramic industry to decrease the melting point, viscosity and thermal expansion of the glassy phase [9,36]. Anhydrous borax (Na 2 B 4 O 7 ) is produced via fusion of borax deca-or pentahydrate at approximately 1000 °C [37]. The anhydrite form of borax is preferred to other hydrous forms in high-temperature applications since it does not cause any foaming problems arising from water dehydration [38].…”