How boric acid can be used as high temperature cosolvent

Speaking of flux, we commonly have glass flux, steel flux, glaze flux and so on. However, we can find that as long as the high temperature flux is inseparable from boric acid, but do you know why boric acid can help melt? In fact, the high temperature flux is to reduce the melting point or freezing point of other substances, promote the acceleration of melting, shorten the melting time, improve the production efficiency. In order to shorten the melting time in the process of production and processing, it is often necessary to add boric acid, because when boric acid is added to the melt, boron trioxide will be formed under the high temperature crucible furnace at about 1000℃, that is, boron oxide, the melting point is about 450℃, it is a strong solvent of acid oxide, this acid can speed up the hydrolysis and dissolution of the material. In the melting process, the impurities in the substances with high melting point can be dissolved, and boron oxide glass phase can be formed in the crystal, which can make the melting more thorough, reduce the influence of crystallization reaction, reduce the liquid phase line temperature of the battering system, promote the acceleration of melting, so as to shorten the melting time. For example, in the production of optical glass, Pyrex glass, instrument glass, etc., it has been proposed that an average of 1% boron oxide can shorten the melting time of 20%-30%.