Boric Acid → Boric acid (HBO2), zinc salt (2:1)

Participants

Reaction Steps

An aqueous solution was prepared by dissolving 72.5 g of boric acid (B2O3 content of 56.3%) in 1000 ml of pure water. To the aqueous solution were added 95.7 g of a zinc flower (ZnO content of 99.4%) and 217.5 g of boric acid (B2O3 content of 56.3%), and were stirred and mixed together such that the molar ratio of B2O3/ZnO was 2.0. Next, the solution was stirred and reacted at 35° C. for 120 minutes. The solution was further stirred and reacted at 90° C. for 4 hours. The obtained product was filtered, washed with water and was, then, dried at 105° C. to obtain a zinc borate (sample H-1). Table 3 shows the chemical composition and properties of the thus obtained zinc borate (sample H-1), FIG. 18 shows an X-ray diffraction image thereof, and FIG. 19 shows an electron microphotograph thereof. From FIG. 18, the obtained zinc borate (sample H-1) was the one of the 2.3 type, but was in the form of mixed crystals of a heptahydrate (2ZnO.3B2O3.7H2O) and a 3.5 type zinc borate (3ZnO.5B2O3.14H2O), exhibiting a peak due to unreacted zinc oxide. The 2.3 type zinc borate was not obtained in a pure form.

Provenance & Evidence