Abstract：The content of aluminum in aluminum manganese alloy was directly determined by fluoride replacement complexometric titration without pre separation of iron and manganese. The samples were dissolved in hydrochloric acid and H2O2. Excessive EDTA solution was added in the presence of copper ion to complex with metals ions such as iron, manganese and copper. The solution was boiled to make aluminum completely form complex. The excessive EDTA was back titrated with lead standard solution using PAN as indicator. Fluoride was added to demask Al EDTA complex, and equivalent EDTA to aluminum was released. Then, it was titrated with standard lead solution to calculate the mass fraction of aluminum. The optimal analytical conditions were tested and obtained. This method was applied to determine aluminum in aluminum manganese alloy, and the relative standard deviation (RSD) was smaller than 0.2 %. The results were consistent with those obtained by classic alkali separation EDTA titration method. This method was used to determine the aluminum-manganese alloy sample containing 15 %-30 % aluminum in mass fraction.
