GB/T 223.14-2000Methods for chemical analysis of iron, steel and alloy. The N-benzoyl-N-phenylhydroxylamine extraction photometric method for the determination of vanadium content (English PDF)

Foreword

This Standard is a revised edition of GB/T 223.14-1989 Methods for Chemical Analysis

of Iron, Steel and Alloy - The N-benzoy-N-phenylhydroxylamine Extraction Photometric

Method for the Determination of Vanadium Content.

In this revised edition, the following chapters and content are added to this Standard.

"Foreword", "2 References", "5 Instruments and Equipment", "6 Sampling and Sample

Preparation" and "10 Test Report". Furthermore, the following provisions are modified.

---The previous 1 is modified into 1 (the title and content of the chapter are

modified);

---The previous 2 is modified into 3 (extraction acidity is modified);

---The previous 3 is modified into 4 (the title of the chapter is modified; explanatory

content is added);

---The previous 4.1 is modified into 7.1 (the expression of sample weighing-taking

is modified);

---The previous 5 is modified into 8 (the result calculation formula and the

description of formula content are modified).

GB/T 223 is under the general title of Methods for Chemical Analysis of Iron, Steel and

Alloy. It includes several independent parts. This Standard is Part 14.

Since the date of implementation, this Standard shall be served as a replacement of

GB 223.14-1989 Methods for Chemical Analysis of Iron, Steel and Alloy - The N-

benzoy-N-phenylhydroxylamine Extraction Photometric Method for the Determination

of Vanadium Content.

This Standard was proposed by the State Bureau of Metallurgical Industry.

This Standard shall be under the jurisdiction of National Technical Committee on Steel

of Standardization Administration of China.

The responsible drafting organization of this standard. Beijing Central Iron & Steel

Research Institute.

The participating drafting organization of this standard. Beiman Special Steel Co., Ltd.

1 Scope

This Standard specifies the N-benzoy-N-phenylhydroxylamine extraction photometric

method for the determination of vanadium content.

This Standard is applicable to the determination of vanadium content in iron, steel and

alloy under the range of 0.0050% (m/m) ~ 0.50% (m/m).

2 References

Provisions that are included in the following standards constitute the provisions of this

Standard through the reference in this Standard. When this Standard was published,

all the announced versions were valid. All the standards will be revised. Parties that

adopt this Standard shall discuss the possibility of adopting the latest versions of the

following standards.

GB/T 222-1984 Method of Sampling Steel for Determination of Chemical

Composition and Permissible Variations for Product Analysis

GB/T 6379-1986 Precision of Test Methods Determination of Repeatability and

Reproducibility for a Standard Test Method by Interlaboratory Tests

3 Method Summary

After dissolving test piece with acid, in the medium of sulfuric acid-phosphoric acid,

use potassium permanganate to oxidize vanadium and pentavalent at room

temperature. Add tantalum reagent-trichloromethane solution; extract the complex of

vanadium into trichloromethane. Then, measure the absorbance at the wavelength of

530 nm.

Interference determination of color developing solution that contains over 1 mg of

molybdenum and titanium. when hydrochloric acid concentration in the extract rises to

6 mol/L, the permissible amount of molybdenum can be raised to 2.5 mg. Use sulfuric

acid-hydrogen peroxide solution to rinse the organic phase, then, the permissible

amount of titanium can be increased to 5 mg.

8 mL of sulfuric acid (4.5) and 8 mL of phosphoric acid (4.7); continue to heat it up,

evaporate it, till it emits smoke. At this moment, if there is carbide that is not damaged,

add drops of nitric acid (4.4), then, re-evaporate it, till it emits smoke. Repeat this step

till carbide is completely damaged. Wait till it is slightly cooled down, then, add 50 mL

of water; heat it up to dissolve salt, then, cool it down to room temperature. Transfer it

into a 100 mL volumetric flask; use water to dilute to the constant volume, then, mix it

up. When there is precipitation, start dry filtration.