Abstract：The rapid determination method of silicon dioxide in laterite by potassium fluosilicate titration was proposed after decomposing the sample with potassium hydroxide melting method. A series of conditions were investigated, including the decomposition of sample, the acidity of precipitation, the filtration and washing mode of precipitation (directly filtrated with absorbent cotton which was covered with little filter paper pulp) and the interference of coexisting elements. Consequently, the corresponding potassium fluosilicate titration determination method of silicon dioxide in laterite was established. Compared with the traditional potassium fluosilicate titration method (the free acid was neutralized by alkali) and perchloric acid dehydration gravimetric method, this method was rapid and easily operated. The proposed method was applied to the determination of SiO2 (5 %39 %) in five laterite samples. The relative standard deviations (RSD, n=9) were 0.45 %0.81 %, and the recoveries were 99 %100 %. Meanwhile, the data among laboratories were compared. The results were consistent with those obtained by classical gravimetric method.
