The GB/T 7731.9-2008 standard specifies two methods for the determination of bismuth content in ferrotungsten: bismuth iodide photometry and Inductance coupled plasma atomic emission spectroscopy (AES). Bismuth iodide photometry is suitable for bismuth content in the range of 0.010% to 0.060%. Samples are treated with nitric acid and hydrofluoric acid, bismuth is settled with ammonium hydroxide, and its Absorbance measurement is performed at a wavelength of 450 nm. Inductance coupled plasma atomic emission spectroscopy (AES) is suitable for bismuth content in the range of 0.010% to 0.15%, providing high-precision analytical results. Both methods can be used to ensure that the bismuth content in ferrotungsten meets mass requirements.
| Status | Active |
|---|---|
| CCS | H11 | ICS | 77.100 |
| Release Date | 2008-08-19 00:00:00 | Implementation Date | 2009-04-01 00:00:00 |