Tungsten Oxide

A purity of more than 99.9% WO3 into a porcelain crucible, porcelain crucible and then placed in a muffle furnace and calcined at 800℃ 1 hour coolish placed in a desiccator, cool room temperature. Accurately weighed 0.25g tungsten trioxide into 100ml beaker, with 20% NaOH20ml, heating completely dissolved, after cooling into 250ml volumetric flask, dilute to the mark and shake, this solution was transferred to a plastic bottle dry spare. Standard curve: accurate absorption 1.00mg / ml solution 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0ml Guarantee 100ml flask were placed with 0.85N ~ NaOH complement to 10ml, plus 50 percent potassium thiocyanate 5ml, plus 1: 1HCL50ml, plus 1% TiCl32ml, diluted with water to the mark and shake for 10 minutes, measured at 721 spectrophotometer extinction 0.5cm cuvette with a wavelength of 420 nm, as a reagent blank reference, drawing working curve, the measured slope of the curve K. Solid phase analysis Weigh a sample in 50ml of 0.200 ~ 0.500g iron crucible...