Abstract：In this study, hydrochloric acid was added into arsenic trioxide to remove arsenic by heating. The obtained residual was dissolved with sodium hydroxide. After acidification with nitric acid, silicon could form silicon molybdenum yellow complex with molybdate at pH 0.9 using ammonium molybdate as color developerWith sulfuric acid increase the acidity,the complex was reduced to silicon molybdenum blue complex by ascorbic acid. The content of silicon dioxide was determined by spectrophotometry. The maximum absorption wavelength of silicon molybdenum blue complex was 813 nm. The relative standard deviations (RSD, n=6) were 1.6 % 1.9 %. The determination results of this method were consistent with those obtained by ICP AES.
