Direct colorimetric determination of small amounts of tungsten in titanium

There is need for a rapid and accurate method for the determination of small amounts of tungsten in titanium. In this paper a direct colorimetric method is proposed for the determination of tungsten in titanium that is applicable to the range of 0.005 to 0.3 per cent. tungsten. The sample is dissolved in hydrochloric acid and the titanium and tungsten reduced with metallic zinc. Thiocyanate is added and the yellow color read at 410 millimicrons with a spectrophotometer. A study was made of the best conditions for developing the color, including the effect of varying amounts of titanium, thiocyanate and hydrochloric acid. An investigation was made to determine the proper wave length for reading the color, the stability of the color and effect of interferences.