GB/T 6150.1-2008 English PDF (GBT6150.1-2008)

This part specifies the method for determination of tungsten trioxide content in tungsten concentrates. This part applies to the determination of tungsten trioxide content in tungsten concentrates. Measuring range: ¡Ý50%. 2 Method summary spectrophotometry The sample is dissolved in hydrochloric acid, nitric acid, and perchloric acid in the presence of a small amount of ammonium fluoride, and concentrated until white smoke is emitted to drive out fluoride ions and nitrate radicals. Tungsten is precipitated in the form of tungsten acid and filtered to separate it from most coexisting elements. The tungstic acid is dissolved in ammonia water, the filtrate is evaporated to dryness, burnt, de-siliconized with hydrofluoric acid, and burnt again; after that, the amount of tungsten trioxide is weighed. The content of tungsten trioxide in the residue is determined by spectrophotometry and the result is corrected. 3 Reagents Unless otherwise stated, the reagents used in this part are analytically pure reagents that comply with national standards or industry standards, and the water used is distilled water. 3.1 Sodium peroxide. 3.2 Ammonium fluoride. 3.3 Disodium ethylenediaminetetraace