Colorimetric and gravimetric determination of silicon in titanium and titanium alloys

Improved colorimetric and gravimetric methods are proposed for the determination of silicon in titanium and titanium alloys. In the colorimetric method the sample is dissolved in hydrofluoric acid. boric acid added and the; titanium oxidized with hydrogen peroxide and permanganate. The bulk of the titanium is precipitated as a crystalline precipitate by heating in boiling water, and the molybdenum color developed. A portion of the solution is filtered and the transmittance measured. In the gravimetric method the sample is fumed with milfuric acid. the silica ignited and fused with aodium carbonate, The silica is then dehydrated with perchloric acid. Thecolorimetric method is recommended for 0.003 to 1.5% silicon, and the gravimetric method for 0.3 to 5% silicon.