This document specifies the phosphorous molybdenum blue spectrophotometric method for the determination of phosphorus in ferrotungsten. This document is applicable to the determination of phosphorus content in ferrotungsten, the determination range (mass fraction): 0.010% ~ 0.080%.
GB/T 7731.4-2021 Referenced Document
GB/T 4010 Ferroallys sampling and preparation of samples for chemical analysis
GB/T 6682 Water for analytical laboratory use.Specification and test methods
GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values
GB/T 7731.4-2021 history
2021GB/T 7731.4-2021 Ferrotungsten—Determination of phosphorus content—Phosphorus molybdenum blue spectrophotometric method
1987GB/T 7731.4-1987 Methods for chemical analysis of ferrotungsten--The molybdenum blue photometric method for the determination of phosphorus content