GB/T 8704.7-2009Ferrovanadium - Determination of phosphorus content - The molybdenum blue photometric method (English PDF)

Foreword

This Part replaces GB/T 8704.7-1994 "spectrophotometric determination of the amount of phosphorus chemical analysis of ferrovanadium molybdenum blue." This portion of the GB/T 8704.7-1994 comparison, the main changes are.

--- After the sample is dissolved insoluble residue filtered washings from "warm" to "warm dilute nitric acid";

--- Will increase the amount of ammonia over by "5mL", to "10mL" precipitation;

--- Amount of carrier solution of ferric chloride was added by precipitation was added 100g/L of ferric chloride solution 5mL or 8mL, to join 50g/L of ferric chloride solution 8mL;

--- The calibration curve is added to the amount of the ferric chloride solution was added a solution of ferric chloride 100g/L of 2mL, was added to 50g/L of Ferric chloride solution 5mL;

--- When the calibration curve "to blank zero" to "to correspond to the reference zero";

--- Measurement range from "< 0.25%" is replaced by "0.010% to 0.25%."

This part of pig iron and ferroalloy by the National Standardization Technical Committee.

This section is drafted. Sichuan Investment Emei Ferroalloy (Group) Co., Ltd.

1 Scope

This section GB/T 8704 provisions of the molybdenum blue spectrophotometric determination of vanadium iron phosphorus content.

This section applies to the determination of phosphorus in ferro-vanadium. Measurement range (mass fraction). 0.010% to 0.250%.

2 Normative references

The following documents contain provisions cited by GB/T 8704 to the present, constitute provisions of this section. For dated reference documents Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this section.

GB/T 4010 alloy chemical analysis and preparation of samples Principle 3 Sample with nitric acid, hydrochloric acid decomposition, oxidation of vanadium used in the ammonia medium, while phosphorus precipitation in the form of iron phosphate, was isolated by filtration. With The precipitate dissolved in nitric acid, perchloric acid after white smoke, sodium bisulfite reduced iron, phosphorus and ammonium molybdate, hydrazine sulfate produced by the reaction of phosphorus molybdenum blue, 825nm wavelength measured absorbance on a spectrophotometer. On the calibration curve Richard mass of phosphorus, calculated the sample of phosphorus content.

4 Reagents and materials

Unless otherwise indicated in the analysis using only recognized as analytical grade reagents and distilled water or its equivalent purity water.

4.1 Nitric acid, rho1.42g/mL.

4.2 Hydrochloride, rho1.19g/mL.

4.3 Perchloric acid, rho1.67g/mL.

4.4 Hydrogen peroxide, rho1.10g/mL.

4.9 sodium bisulfite solution, 100g/L. Weigh 50g of sodium bisulfite (of NaHSO3) into 600mL beaker was added 500mL Dissolved in water, and mix.

4.10 ferric chloride solution, 50g/L. Weigh 5g of ferric chloride (FeCl3 · 6H2O), placed in 400mL beaker, add 10mL hydrochloric acid (1 + 1) and 90mL water to dissolve and mix.