Kinetics of fluid–solid reaction with an insoluble product: zinc borate by the reaction of boric acid and zinc oxide

Abstract Zinc borate having the formula of 4ZnO·B2O3·H2O has been used as a fire retardant for polymers requiring high processing temperatures since it has a high dehydration temperature (around 415°C). The effects of reaction time, reaction temperature were investigated on the heterogeneous reaction between solid zinc oxide and boric acid solution. A stoichiometric amount of zinc oxide and 5.0% excess boric acid were used in experiments and the other parameters, mixing speed (1700 rpm), the solid-liquid ratio of 20%, and the amount of seed crystal (3.9% wt) were kept constant for all experiments. A 91.1% conversion was obtained at 120°C for 5 h of reaction time. Precipitated product was filtered and washed by hot water to remove the excess boric acid. Finally it was dried until reaching to a constant mass in an air circulating oven at 105°C. Powder products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectrum and XRD pattern of powders are consistent with data of the zinc borate given in the literature. According to SEM analysis, whiskers are less than 1 μm in diameter and their lengths are in the range of 1–10 μm.

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Optimization and modeling of zinc borate (2ZnO·3B2O3·3.5H2O) production with the reaction of boric acid and zinc oxide

Journal of Industrial and Engineering Chemistry ◽

10.1016/j.jiec.2010.09.018 ◽

2011 ◽

Vol 17 (3) ◽

pp. 493-497 ◽

Cited By ~ 7

Author(s):

Osman Nuri Ata ◽

Enes Şayan ◽

Bengül Engin

Keyword(s):

Zinc Oxide ◽

Boric Acid ◽

Zinc Borate

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Scale-up synthesis of zinc borate from the reaction of zinc oxide and boric acid in aqueous medium

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2010.05.048 ◽

2010 ◽

Vol 312 (22) ◽

pp. 3361-3366 ◽

Cited By ~ 15

Author(s):

Mert Kılınç ◽

Gaye Ö. Çakal ◽

Sertan Yeşil ◽

Göknur Bayram ◽

İnci Eroğlu ◽

...

Keyword(s):

Zinc Oxide ◽

Boric Acid ◽

Aqueous Medium ◽

Scale Up ◽

Zinc Borate

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Effect of Temperature and Time on Zinc Borate Species Formed from Zinc Oxide and Boric Acid in Aqueous Medium

Industrial & Engineering Chemistry Research ◽

10.1021/ie0610243 ◽

2007 ◽

Vol 46 (8) ◽

pp. 2367-2371 ◽

Cited By ~ 20

Author(s):

H. Emre Eltepe ◽

Devrim Balköse ◽

Semra Ülkü

Keyword(s):

Zinc Oxide ◽

Boric Acid ◽

Aqueous Medium ◽

Zinc Borate ◽

Effect Of Temperature

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Effect of Zinc, Zinc Oxide and Zinc Borate on the Flammability of Polycarbonate

Journal of Fire Sciences ◽

10.1177/073490419501300305 ◽

1995 ◽

Vol 13 (3) ◽

pp. 224-234 ◽

Cited By ~ 2

Author(s):

Ramazan Benrashid ◽

Gordon L. Nelson ◽

Donald J. Ferm ◽

Leland W. Chew

Keyword(s):

Zinc Oxide ◽

Heat Release ◽

Oxygen Index ◽

Ohio State University ◽

Zinc Borate ◽

State University ◽

Dsc Studies ◽

Release Studies ◽

Chamber Studies ◽

Smoke Chamber

Polycarbonate was blended with zinc, zinc borate (2ZnO·3B2O 3·3.5H2O) and zinc oxide. Blends made of zinc/polycarbonate and especially zinc borate/polycarbonate show major improvement in oxygen index values. Ohio State University (OSU) heat release studies show reduction in heat release only for zinc borate/polycarbonate blends compared to virgin polycarbonate. No improvement in smoke suppression was observed from NBS Smoke Chamber studies for these blends. From DSC studies there was a low ering of Tg's. Thermogravimetric analyses show the blends have lower tempera ture stability in nitrogen (50% weight loss) compared to a control.

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