Potassium triboron pentaoxide

Endpoint summary

Additional information

It is anticipated that if Orthoboric acid, potassium salt could be isolated from the chemical matrix in which it is formed, it would

behave similarly with respect to the properties observed for boric acid itself. Boric acid was determined to be a white odourless crystalline solid. No melting point for boric acid can be defined in the range 25 - 1000 °C due to the decomposition of the substance. If heated above 100 °C, water is lost and boric acid converts initially to metaboric acid (HBO₂) and on further heating forms boric oxide (B₂O₃). A boiling point is not applicable for boric acid, which starts to give off water and decomposes at above 100 °C first forming metaboric acid and is converted into boric oxide (B2O3), which has a boiling point of 2200 °C. The relative density of boric acid is 1.49 at 23ºC. Boric acid has a vapour pressure of 0.0000099 Pa at 25ºC and log Pow of -1.09 at 22ºC. Boric acid is water soluble (49.2 g/L at 20ºC). Boric acid is not flammable, is not a pyrophoric or self-heating substance and emits no flammable gases on contact with water. A fully saturated solution of boric acid in water is a candidate for classification as a corrosive substance of UN Class 8, Packing group III (according to the UN Transport of Dangerous Goods Recommendations). Boric acid had a mean particle size distribution d50 of 74.395μm and a dissociation constant of 8.94 at 20 °C.

Studies on dustiness were performed according to CIPAC method MT 171 and showed that boric acid granular which has a particles size (d50 mm) of 0.608 (mm) was dust category 1 - nearly dust free. This sample represents the most representative of those placed on the market. Boric acid TP, which has a particle size (d50) of 119μm was dust category 2 - essentially non-dusty. Boric acid powder, which has a particle size (d50 mm) of 0.051 (mm) was dust category 3 - dusty. This sample represents the finest grade placed on the market.