Phosphatic Tungstic Vanadic Acid
Phosphatic tungstic vanadic acid is a yellow complex, it isn’t sold in the market. It is usually used as indicator to determine vanadium content. It can be generated during the experiment, the color intensity is influenced by the vanadium content. Potassium and ammonium can react with phosphatic tungstic vanadic acid agent to generate phosphatic tungstic vanadic acidate or phosphotungstate precipitation. Iodide, thiocyanate ions and other reducing agents are capable of reducing vanadium phosphotungstic acid.
Phosphotungstic acid photometric determine of vanadium in the ore, the principle is vanadium (Ⅴ) in an acidic solution and capable of forming yellow phosphotungstic acid complex by reacting with phosphoric acid and sodium tungstate, and the color depth and proportional to the amount of vanadium. In addition, phosphotungstic acid is also found in determining vanadium by spectrophotometry in stone coal vanadium. Prepared mentioning that molybdenum (Ⅵ) under coloration with phosphate also generate yellow complex, but the color intensity is weak, if the amount is no more than 50 times of vanadium which has no effect on the experiment; and when the sample contains a large number of molybdenum, the other can take solution without sodium tungstate solution as reference, in order to eliminate the effects of molybdenum.