重量法测定含氟矿石中的二氧化矽,通常用二种方法以防止氟的干扰。这些方法是:(甲)在微弱的碱性溶液中,使矽酸沉淀;(乙)用硼酸阻止氟的干扰。Berzelius-Hillebrand 法属于第一种,此法费时较长。Jannasch 与 Weber 首先用硼酸阻止氟的干扰。他们用硼酸酐与含氟的矽酸盐熔化,并证明二氧化矽不致损失。Specht 重复过这个方法。所得熔物往往不易用水浸提。Schrenk 与 Ode Gravimetric determination of silica in the fluorine ore, usually two ways to prevent fluorine interference. These methods are: (A) Precipitating silicic acid in a weak basic solution; (B) Preventing fluorine interference with boric acid. Berzelius-Hillebrand law belongs to the first, this method takes longer. Jannasch and Weber first used boric acid to stop fluorine interference. They melted boric anhydride with fluorosilicate and proved that silica did not lose. Specht repeated this method. The resulting melt is often not easy to use water extraction. Schrenk and Ode