RAPID PHOTOMETRIC DETERMINATION OF PHOSPHORUS IN STEEL

Abstract

The procedures described were developed to provide a method for determination of the phosphorus in steel that is free from some of disadvantages in the conventional photometric method.
Dissolve a 0.1 gram sample in a 200ml Erlenmyer flask with 3ml of nitric acid (1 to 1) and 5ml of perchloric acid (60%). Evaporate to fumes and then fume for approximately 2 minutes, cool, add 60ml of water, and 0.5 gram of sodium sulfite, heat to boiling, and cool to 10 to 20°C. Precipitate the iron by the dropwise addition of ammonium hydroxide (1 to 1), and add 8ml of sulfuric acid (1 to 5). Transfer to a 100ml volumetric flask, add 5ml of ammonium molybdate solution (5%). After 1 to 2 minutes, add 10ml of sodium fluoride solution (5%) and 0.05ml of stannous chloride solution (10%). Dilute to the mark and mix. Measur the transmittancy against water at 660mμ.