Abstract:Analytical methods for determination of Al and Si in three raw materials were discussed. Aluminum content was determined with volumetric method. Excess EDTA was added to acidic solution to form Al -EDTA complex and mask residue elements. In slightly acidic solution , the EDTA in excess was titrated with zinc chloride standard solution with xylenol orange as the indicator. Furthermore, the Al -EDTA complex was treated with ammonium fluoride and then the equal amount of EDTA was released into solution. The solution was titrated once more with zinc chloride standard solution and orange red color indicated the titration endpoint. The Al2O3 content was calculated by the volume of zinc chloride solution that was consumed. Gravimetric method was used to determine the silicon content. The melting sample was treated to form silicate precipitation. After incandesce and weighing, sulfuric acid and hydrofluoric acid were used for disposal of the silicon and then repeat incandesce and weighing. The content of SiO2 was determined according to the difference between the two weights. The two methods are both classic, accurate and reliable and can be widely used.