酸碱滴定法快速测定硅锰铝合金中硅

利用氟硅酸钾溶解于沸水中生成氢氟酸的原理。试样以硝酸、氢氟酸溶解，硅转化为硅氟酸，加入硝酸钾生成氟硅酸钾沉淀。经过滤、洗涤沉淀中的游离酸后，溶解于中性沸水中，生成氢氟酸，以溴麝香草酚蓝为指示剂，用氢氧化钠标准溶液滴定游离出的氢氟酸，借此测定硅锰铝合金中硅含量，其相对标准偏差小于0．0796％。

Fast Determination of Silicon in Silico-manganese-aluminum Alloy by Acid-base titration

In light of the principle of potassium fluosilicate, dissolved in boiling water, forming hydrofluoric acid, after the sample is dissolved in nitric acid or hydrofluoric acid, silicon is translated into fluosilicic acid and potassium nitrate is added to form potassium siliofluoride precipitation, which, after dissociate acid is filtrated and washed, dissolves in neutral boiling water to form hydrofluoric acid, with bromine thymol blueness as an indicator, the standard sodium hydroxide solution is used to titrate the dissociated hydrofluoric acid, by which the silicon coetent in silico-manganese-aluminum alloy is determinated, with a relative standard deviation less than 0. 0996%.