氟铝酸钾法快速测定铝合金及铝盐中铝含量的研究

Study on Rapid Determination of Aluminum Content in the Aluminum Alloy and Aluminum Salt by Using Potassium Fluoroaluminate

研究了采用氟铝酸钾法快速测定铝合金及铝盐中的含铝量。试样溶解并消除干扰后,先在pH(7～8)时,用稀NaOH溶液将Al3+沉淀为Al(OH)3,再加入KF,生成K3AlF6,并释放出游离碱。反应中析出的游离KOH溶液,以酚酞为指示剂,用HCl标准溶液滴定至终点。测定结果的RSD=0.33%,加标回收率为R=97.10%～101.06%。结果表明,改进后简单、快速、准确、干扰小,是一种既可满足于生产要求,又便于学生实验的准确而快捷的测铝方法。

The method of rapid determining aluminum content in aluminum alloy and aluminum salt by using potassium fluoroaluminate are studied. After the sample is dissolved and the disturbance eliminated, the Al^3＋ is deposited as Al（OH）3 by using thin solution of NaOH,while that remains pH （7-8）. Then,KF is added,K3AlF6 is produced and dissociated KOH is released. With phenolphthalein as the indicator and HCl as the standard solution, dissociated KOH is titrated to end point. The relative standard deviation of determination results is 0.33%, and the recovery rate of add standard is between 97.10%～101.06%. The results show that the improved method is simple, quick, accurate and with little disturbance. It is an accurate and fast way of determining aluminum content, which can not only meet the demand of production but can also be used in experiment designed. The method has achieved desired results in the experiments conducted.