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| GB/T 223.13-2025 | 335 | Add to Cart | Auto, 9 seconds. | Iron, steel and alloy - Determination of vanadium content - Titrimetric method and spectrophotometric method | Valid |
| GB/T 223.13-2000 | 209 | Add to Cart | 3 days | Methods for chemical analysis of iron, steel and alloy. The ammonium ferrous sulfate titration method for the determination of vanadium content | |
| GB/T 223.13-1989 | RFQ | ASK | 3 days | Methods for chemical analysis of iron, steel and alloy--The ammonium ferrous sulfate titration method for the determination of vanadium content | Obsolete |
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GB/T 223.13-2025: Iron, steel and alloy - Determination of vanadium content - Titrimetric method and spectrophotometric method
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GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 77.080.01 CCS H 11 Replacing GB/T 223.13-2000, GB/T 223.14-2000 Iron, steel and alloy -- Determination of vanadium content -- Titrimetric method and spectrophotometric method (ISO 4942.2016, Steels and irons -- Determination of vanadium content -- N-BPHA spectrophotometric method, MOD) Issued on: AUGUST 29, 2025 Implemented on: MARCH 01, 2026 Issued by. State Administration for Market Regulation; Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3 Introduction... 6 1 Scope... 7 2 Normative references... 7 3 Terms and definitions... 8 4 Method One -- Ferrous ammonium sulfate titration method... 8 5 Method Two -- N-BPHA (tantalum reagent) extraction spectrophotometric method ... 13 6 Method Three -- Tantalum reagent extraction spectrophotometric method... 19 7 Test report... 24 Annex A (informative) Constituent documents of GB/T 223... 25 Annex B (informative) Comparison with ISO 4942.2016... 31 Annex C (informative) Additional information for Method One precision test... 33 Annex D (informative) Method Two precision specimen information (supplementary information for international interlaboratory testing)... 36 Iron, steel and alloy -- Determination of vanadium content -- Titrimetric method and spectrophotometric method WARNING -- Personnel using this document shall have practical experience working in a formal laboratory. This document does not address all potential safety issues. Users are responsible for taking appropriate safety and health precautions and ensuring compliance with relevant national regulations.1 Scope
This document the methods for determining vanadium content using ferrous ammonium sulfate titration and tantalum reagent extraction spectrophotometry. This document applies to the determination of vanadium content in steel and alloys. Method One is the ferrous ammonium sulfate titration method, applicable to the determination of vanadium content in steel and alloys with a mass fraction of 0.1% to 10.0%. It is not applicable to the determination of vanadium content in the following samples. a) specimens containing more than 20% cobalt (mass fraction); b) specimens containing more than 0.01% cerium (mass fraction); c) specimens containing more than 20% chromium, more than 20% manganese, or more than 18% tungsten (mass fraction), with a vanadium content less than 0.4%. Method Two is the N-BPHA (tantalum reagent) extraction spectrophotometric method, applicable to the determination of vanadium content in steel and cast iron with a mass fraction of 0.005%~0.50%. Method Three is the tantalum reagent extraction spectrophotometric method, applicable to the determination of vanadium content in steel and alloys with a mass fraction of 0.005%~0.50%.2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 6379.1, Accuracy (trueness and precision) of measurement methods and results -- Part 1.General principles and definitions (GB/T 6379.1-2004, ISO 5725- 1.1994, IDT) GB/T 6379.2, Measurement methods and results -- Accuracy (trueness and precision) -- Part 2.Determine the standard methods of measurement repeatability and reproducibility of the basic method (GB/T 6379.2-2004, ISO 5725-2.1994, IDT) GB/T 6682, Water for analytical laboratory use -- Specification and test methods (GB/T 6682-2008, ISO 3696.1987, MOD) GB/T 7729, Chemical analysis of metallurgical products -- General rule for spectrophotometric methods GB/T 12805, Laboratory glassware -- Burettes (GB/T12805-2011, ISO 385.2005, NEQ) GB/T 12806, Laboratory glassware -- One-mark volumetric flasks (GB/T 12806- 2011, ISO 1042.1998, NEQ) GB/T 12808, Laboratory glassware - One mark pipettes GB/T 20066, Steel and iron -- Sampling and preparation of samples for the determination of chemical composition (GB/T 20066-2006, ISO 14284.1996, IDT) ISO 648, Laboratory glassware -- One-mark pipettes3 Terms and definitions
This document does not contain any terms or definitions that need to be defined.4 Method One -- Ferrous ammonium sulfate titration method
4.1 Principle After the test material is dissolved in a suitable acid, vanadium is oxidized with potassium permanganate at room temperature in a sulfuric acid-phosphoric acid medium. Excess potassium permanganate is reduced with sodium nitrite. Excess sodium nitrite is decomposed with urea. Vanadium is titrated with a standard ferrous ammonium sulfate solution using benzoic acid as an indicator. 4.2 Reagents and materials In the analysis, unless otherwise specified, only analytically pure reagents and Grade II water or water of equivalent purity as specified in GB/T 6682 shall be used. 4.2.1 Hydrochloric acid. ρ is approximately 1.19 g/mL. 4.2.2 Nitric acid. ρ is approximately 1.42 g/mL. 4.2.3 Sulfuric acid (5+95). diluted with sulfuric acid (ρ approx. 1.84 g/mL). 4.2.4 Phosphoric acid. ρ is approximately 1.69 g/mL. 4.2.5 Sulfuric acid-phosphoric acid mixture. while stirring, slowly add 200 mL of sulfuric acid (ρ is approximately 1.84 g/mL) to 400 mL of water. Let cool slightly. Add 100 mL of phosphoric acid (4.2.4). Mix well. 4.2.6 Potassium permanganate solution. 3 g/L. 4.2.7 Sodium nitrite solution. 20 g/L. 4.2.8 Urea solution. 200 g/L. 4.2.9 Ferrous ammonium sulfate [(NH4)2Fe(SO4)2·6H2O] solution. 40 g/L. Weigh 40.0 g of ferrous ammonium sulfate hexahydrate [(NH4)2Fe(SO4)2·6H2O]. Dissolve in sulfuric acid (4.2.3) and dilute to 1000 mL. Mix well. 4.2.10 Benzyl anthranilic acid solution. 2 g/L. Weigh 0.2 g of benzo (o-aminobenzoic acid) into a 300 mL beaker. Add 0.2 g of anhydrous sodium carbonate. Add 20 mL of water and heat to dissolve. Dilute with water to 100 mL. Mix well. 4.2.11 Sodium arsenite solution. 5 g/L. Weigh 0.38 g of arsenic trioxide. Dissolve in 50 mL of sodium hydroxide solution (50 g/L). Neutralize with sulfuric acid (ρ is approximately 1.84 g/mL, 1+1) until the solution is neutral. Dilute with water to 100 mL. Mix well. Alternatively, sodium arsenite can be used. Weigh 0.5 g of sodium arsenite and dissolve it in water. Dilute to 100 mL. Mix well. 4.2.12 Potassium dichromate standard solution [c(1/6K2Cr2O7) = 0.01000 mol/L]. Weigh 0.4903 g of potassium dichromate, which has been pre-dried at 150°C for 1 h and cooled to room temperature in a desiccator. Place it in a 300 mL beaker. Dissolve it in water. Transfer the solution to a 1000 mL volumetric flask. Dilute to the mark with water. Mix well. 4.2.13 Ferrous ammonium sulfate standard solution {c[(NH4)2Fe(SO4)2·6H2O] = 0.01 mol/L}. 4.2.13.1 Preparation. Weigh 4.0 g of ferrous ammonium sulfate hexahydrate [(NH4)2Fe(SO4)2·6H2O]. Dissolve in sulfuric acid (4.2.3) and dilute to 1000 mL. Mix well. 4.2.13.2 Calibration and indicator calibration. Take three 250 mL Erlenmeyer flasks. Add 15 mL of sulfuric acid (ρ is approximately 1.84 g/mL) and 10 mL of phosphoric acid (4.2.4) to each. Heat to evaporate until sulfuric acid fumes are emitted. Let cool slightly. Add 50 mL of water. Cool to room The specimens used, the raw data of the precision tests, and the statistical results are listed in Tables C.1, C.2, and C.3 of Annex C. A graph of the precision data is shown in Figure C.1. The repeatability limit (r) and reproducibility limit (R) are obtained according to the equations given in Table 2. Under repeatability conditions, the absolute difference between two independent test results shall not exceed the repeatability limit (r), provided that the number of cases exceeding the repeatability limit (r) does not exceed 5%. Under reproducibility conditions, the absolute difference between two independent test results shall not exceed the reproducibility limit (R), provided that the number of cases exceeding the reproducibility limit (R) does not exceed 5%.5 Method Two -- N-BPHA (tantalum reagent) extraction
spectrophotometric method 5.1 Principle Dissolve the test material in a suitable acid. Add phosphoric acid to the solution, so as to eliminate interference from iron. Add potassium permanganate to oxidize vanadium to V(V). Excess permanganate is selectively reduced with sodium nitrite. In the presence of urea, add N-BPHA (tantalum reagent) and hydrochloric acid to form a complex. The mixture is then extracted with chloroform. Measure the absorbance at 535 nm. 5.2 Reagents Unless otherwise specified, only reagents confirmed to be analytically pure and water of Grade II or equivalent purity as specified in GB/T 6682 shall be used in the analysis. 5.2.1 Hydrochloric acid. ρ is approximately 1.19 g/mL. 5.2.2 Hydrochloric acid (4+1). add 400 mL of hydrochloric acid (5.2.1) to 100 mL of water. 5.2.3 Nitric acid. ρ is approximately 1.42 g/mL. 5.2.4 Perchloric acid. ρ is approximately 1.67 g/mL. WARNING -- Perchloric acid vapors can typically cause explosions in the presence of ammonia, nitrite fumes, or organic matter. 5.2.5 Phosphoric acid. ρ is approximately 1.69 g/mL. 5.2.6 Phosphoric acid (1+1). add 250 mL of phosphoric acid (5.2.5) to 250 mL of water. 5.2.7 Hydrochloric acid/nitric acid mixed acid (3+1). mix 300 mL of hydrochloric acid (5.2.1) with 100 mL of nitric acid (5.2.3). Prepare when needed. 5.2.8 Hydrogen peroxide solution. 30%. 5.2.9 Sodium nitrite solution. 3 g/L. 5.2.10 Urea solution. 250 g/L. 5.2.11 Sodium tripolyphosphate (Na5P3O10) solution. 100 g/L. 5.2.12 Potassium permanganate solution. 3 g/L. 5.2.13 Chloroform. 5.2.14 N-Benzoylphenyl hydroxylamine [C6H5CON(OH)C6H5] (N-BPHA, also known as tantalum reagent) - chloroform solution. 2.5 g/L. Dissolve 0.25 g of N-BPHA in 100 mL of chloroform (5.2.13). The solution shall be stored in a brown bottle. Otherwise, it shall be prepared when needed. 5.2.15 Iron solution. 10 g/L. Weigh 5.0 g of pure iron (vanadium-free or with the lowest possible and known vanadium content), accurate to 1 mg. Transfer to a 500 mL beaker. Cover with a watch glass. Add 100 mL of a hydrochloric acid/nitric acid mixture (5.2.7). After the vigorous reaction stops, heat slowly until completely dissolved. Add 100 mL of perchloric acid (5.2.4). Heat until white perchloric acid fumes appear and reflux in the beaker. Continue fuming for about 3 min. Cool. Add 100 mL of hot water. Shake to dissolve the salt. Add a few drops of hydrogen peroxide solution (5.2.8). Heat to boiling. Maintain boiling for about 2 min. After cooling, transfer to a 500 mL volumetric flask. Dilute to the mark with water. Mix well. 5.2.16 Vanadium standard solution. 1.0 g/L. Dry several grams of ammonium metavanadate (NH4VO3) in an oven at 100°C~105°C for at least 1 h. Then cool to room temperature in a desiccator. Drying at temperatures ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
