GB/T 223.31-2008 PDF English
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Iron, steel and alloy -- Determination of arsenic content -- Distillation-molybdenum blue spectrophotometric method
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| GB/T 223.31-1994 | English | 199 |
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Methods for chemical analysis of iron, steel and alloy. The distillation-molybdenum blue spectrophotometric method for the determination of arsenic content
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| GB 223.31-1984 | English | 199 |
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Methods for chemical analysis of iron, steel and alloy--The distillation-molybdenum blue photometric method for the determination of arsenic content
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GB/T 223.31-2008: PDF in English (GBT 223.31-2008) GB/T 223.31-2008
Iron, steel and alloy. Determination of arsenic content. Distillation-molybdenum blue spectrophotometric method
ICS 77.080.01
H11
National Standards of People's Republic of China
GB/T 223.31-2008/ISO 17058..2004
Replacing GB/T 223.31-1994
Iron, steel and alloy - Determination of arsenic content
Distillation separation - molybdenum blue spectrophotometry
(ISO 17058..2004, IDT)
2008-05-13 released
2008-11-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
China National Standardization Administration released
Foreword
This part of GB/T 223 is equivalent to using ISO 17058..2004 "Determination of arsenic content of steel spectrophotometry."
For ease of use, this section made the following editorial changes.
a) Replace "this International Standard" with "this Part";
b) Use the decimal "." instead of the comma "," as the decimal point;
c) delete the preface to international standards;
d) In the "normative references", the referenced international document or the quoted specific clause is exactly the same as the domestic document,
In the document instead.
This Part Replaces GB/T 223.31-1994 "Methods for Chemical Analysis of Iron, Steel and Alloy Distillation - Determination of molybdenum blue spectrophotometry
Arsenic content. "
This section compared with GB/T 223.31-1994, the main changes made to the following.
--- Reducing agent "20mL sulfuric acid trap - potassium bromide mixed solution" to "2g sulfuric acid trap - potassium bromide mixture", while reducing the increase
Into the distillation flask acid volume, shorten the distillation time;
--- Calibration curve by the uniform use of 10μg/mL arsenic standard solution formulated for different content of the calibration curve using different concentrations
Degree of arsenic standard solution preparation;
--- Increased 2.0μg/mL arsenic standard solution.
This part of the Appendix A, Appendix B is an informative annex.
This part is proposed by China Iron and Steel Association.
This part of the National Standardization Technical Committee Steel centralized.
This section mainly drafted by. China Steel Research Technology Corporation.
The main drafters of this section. Luo Qianhua, Yu Dingzhi, Ge Ru Bin.
This part of the standard replaces the previous editions are.
--- GB/T 223.31-1984, GB/T 223.31-1994.
GB/T 223.31-2008/ISO 17058..2004
Iron, steel and alloy - Determination of arsenic content
Distillation separation - molybdenum blue spectrophotometry
Warning. Personnel using this section should have practical experience in formal laboratory work. This section does not indicate all possible security issues.
It is the user's responsibility to take appropriate safety and health measures and to ensure compliance with the requirements of the relevant state laws and regulations.
1 range
This section GB/T 223 specifies the distillation separation - molybdenum blue spectrophotometric determination of arsenic content.
This section applies to the determination of arsenic content of 0.0005% ~ 0.10% in steel and alloy.
2 Normative references
The following documents contain provisions that, through reference in this section, become the provisions of this part of GB/T 223. Any reference to the date of the citation
All subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to be reached under this section
The parties to the agreement study whether the latest versions of these documents are available. For undated references, the latest version applies to this book
section.
GB/T 6379.1 Accuracy (accuracy and precision) of measurement methods and results - Part 1. General and definitions
(GB/T 6379.1-2004, ISO 5725-1..1994, IDT)
GB/T 6379.2 Accuracy (accuracy and precision) of measurement methods and results - Part 2. Determination of the weight of standard measurement methods
Fundamentals of renaturation and reproducibility (GB/T 6379.2-2004, ISO 5725-2..1994, IDT)
GB/T 20066-2006 Sampling and sample preparation methods for the determination of chemical compositions of steel and iron (ISO 14284..1996, IDT)
ISO 385-1. 1984 Laboratory glassware burets - Part 1. Basic requirements
Laboratory glassware single standard pipette
ISO 1042..1998 Laboratory glassware Monoscript wire capacity bottles
ISO 3696. 1987 Analysis of laboratory water specifications and test methods
ISO 5725-3 Accuracy (accuracy and precision) of measurement methods and results - Part 3. Standard measurement methods Precision
Interval measurement
3 principle
The sample was dissolved in hydrochloric acid, nitric acid mixed acid, adding sulfuric acid, continue to heat to take sulfuric acid white smoke. In sulfuric acid and hydrochloric acid medium, add sulfuric acid
Hydrazine and potassium bromide reduce arsenic and separate it by distillation in the form of AsCl3. The distillate is absorbed by nitric acid and As (III) is oxidized to As (V). To
Hydrazine sulfate as a reducing agent, arsenic and ammonium molybdate blue molybdenum complexes formed. Spectrophotometry was performed at a wavelength of 840 nm.
4 Reagents and materials
In the analysis, unless otherwise stated, only certified analytical reagents and Grade III water as defined in ISO 3696. 1987 are used.
4.1 Hydrochloric acid, p approximately 1.19 g/mL.
4.2 nitric acid, p about 1.40 g/mL.
4.3 Nitric acid, ρ approximately 1.40 g/mL, diluted to 3 + 1.
4.4 Mixed acids. A volume of nitric acid (4.2) is added to four volumes of hydrochloric acid (4.1).
4.5 sulfuric acid, p about 1.84 g/mL.
4.6 sulfuric acid, ρ about 1.84g/mL, diluted to 1 +1. While cooling in the water and stirring constantly, a certain volume of sulfuric acid (4.5) min
GB/T 223.31-2008/ISO 17058..2004
Several times to join an equal volume of water.
4.7 sulfuric acid, ρ about 1.84g/mL, diluted to 1 +6. While cooling in the water and stirring constantly, a certain volume of sulfuric acid (4.5) min
Several times into six times the volume of water.
4.8 reductant powder mixture. According to a certain percentage, weighed 2.5g of hydrazine sulfate and 10g of potassium bromide, placed in a mortar, with research sticks fine, and
Mix well, spare.
4.9 ammonium molybdate solution, (NH4) 6Mo7O24 4H2O, 10 g/L.
4.10 hydrazine sulfate solution, N2H6SO4, 0.6g/L.
4.11 arsenic standard solution
4.11.1 stock solution, equivalent to 0.20g of arsenic per liter. Weigh 0.1320g arsenic trioxide (As2O3), accurate to 0.0001g, placed
100mL beaker, slowly add 10mL nitric acid (4.2), cover the watch glass, slowly heated until completely dissolved. Add 2 mL of sulfuric acid
(4.6), slowly heat up, get rid of nitrogen oxides, continue to evaporate to take a large amount of white smoke. Remove the cold, rinse the watch glass and cup wall with a little water, again
Evaporation to take a lot of white smoke. Remove the cooling, add about 10mL of water, slightly heated until the salts dissolved, the solution becomes clear so far. Cool to room temperature,
The solution was quantitatively transferred to 500mL single-labeled volumetric flask, diluted with water to the mark, and mix. This stock solution 1 mL contains 0.2 mg of arsenic.
4.11.2 Standard solution A, equivalent to 0.01g of arsenic per liter. Pipette 25.00mL stock solution (4.11.1), in 500mL single-standard line capacity
Bottle, diluted with water to the mark, mix well. When used with the time. This standard solution 1mL containing 10μg arsenic.
4.11.3 Standard solution B, equivalent to 0.002g a liter per liter. Pipette 50.00mL standard solution (4.11.2), in 250mL single standard line capacity
Bottle, diluted with water to the mark, mix well. When used with the time. This standard solution 1mL contains 2μg of arsenic.
4.12 Potassium bromide.
5 instruments and equipment
All glass feelers shall comply with Class A of ISO 385-1. 1984, ISO 648..1997 and ISO 1042..1998.
Normal laboratory equipment and the following instruments are used.
5.1 Spectrophotometer, suitable for measuring the absorbance of a solution with a 4 cm (or 1 cm) absorption cuvette at 840 nm.
5.2 Distillation unit, see Figure 1.
1 --- Erlenmeyer flask (distillation flask), 250mL;
2 --- thermometer
3 --- thermometer casing;
4 --- absorption liquid beaker, 100mL;
5 --- cooling water beaker, 1000mL;
6 --- valve.
Figure 1 set arsenic distillation unit
GB/T 223.31-2008/ISO 17058..2004
6 take samples
In accordance with GB/T 20066-2006 or appropriate national standards for steel sampling.
7 Analysis steps
7.1 Sample volume
According to Table 1 Weigh the sample, accurate to 0.1mg.
Table 1 Sample amount
Arsenic content (mass fraction) /% sample amount/g
0.0005 ~ 0.001 1.0
> 0.001 to 0.006 0.50
> 0.006 ~ 0.100 0.10
7.2 blank test
Parallel to the sample analysis, using the same analysis steps, the same quality reagents do blank test.
7.3 Determination
7.3.1 Preparation of test solution
The sample (7.1) placed in a 150mL beaker, add 10mL ~ 20mL mixed acid (4.4), cover the watch glass, slowly heated until
completely dissolved. Cooling, remove the watch glass, add 20mL sulfuric acid (4.6), cover the watch glass and leave a small mouth, so that the smoke can be discharged and evaporated
Take a lot of white smoke. Remove and cool.
7.3.2 Distillation
The test solution (7.3.1) is quantitatively transferred to a distillation flask and the watch glass and cup wall are rinsed with about 10 mL of water. If there is insoluble sulfate, plus
A small amount of water, slightly warm until the salt is completely dissolved. After cooling with water, 10 mL of hydrochloric acid (4.1) and 2.0 g of reductant powder mixture were added
(4.8), mix well. Add 10mL nitric acid (4.3) in the absorption liquid beaker, the absorption liquid beaker is placed in a chilled water cooling water beaker.
Connect the distillation device, heat the distillation flask on the low-temperature electric furnace until the temperature reaches 125 ℃ stop heating, the entire distillation process in 6min ~
Within 10min. Open the valve to prevent the solution from flowing backwards through the beaker. Remove the distillation flask, rinse the lower end of the trachea with a small amount of water, the washing liquid
Into the absorption liquid beaker. Add 3.5mL sulfuric acid (4.7), mix.
Cover the watch glass and leave a small hole to allow the smoke to drain and evaporate to a large amount of white smoke. In the process should not blister. take
, Cool down, rinse the watch glass and beaker wall with water, evaporate again to take white smoke to drive away nitrogen oxides. Remove, cool and rinse the surface with water
Dispense the solution quantitatively into a 50 mL single-labeled volumetric flask.
7.3.3 Formation of colored complexes
Add 2.5mL ammonium molybdate solution (4.9) and 2.5mL hydrazine sulfate solution (4.10) in the volumetric flask, diluted with water to the mark, and mix. in
Heated in boiling water bath for 10min, removed, cooled to room temperature.
7.3.4 Spectrophotometric determination
With water as a reference, adjust the absorbance of the spectrophotometer to zero. With 4cm (or 1cm) absorption dish, at a wavelength of about 840nm at the color
Liquid spectrophotometry.
7.4 Calibration curve establishment
7.4.1 Preparation of calibration solution
For arsenic content (mass fraction) of 0.0005% ~ 0.030% and arsenic content (mass fraction) of 0.030% ~ 0.100%, respectively, according to
Table 2 and Table 3, the corresponding volume of arsenic standard solution (4.11.2,4.11.3) added to a series of 50mL single-labeled volumetric flask. In each capacity
The volumetric flask was added 2.5mL sulfuric acid (4.7). According to 7.3.3.
7.4.2 Spectrophotometric determination
With water as a reference, adjust the absorbance of the spectrophotometer to zero. With 4cm (or 1cm) absorption dish, at a wavelength of about 840nm at a certain
GB/T 223.31-2008/ISO 17058..2004
Range calibration solution for spectrophotometric determination.
7.4.3 Calibration curve drawing
Calculate the difference between the calibration solution and the calibration blank solution in net absorbance.
The straight line passing through the origin is taken from the net absorbance and the corresponding mass of arsenic (μg).
For the arsenic content (mass fraction) of 0.0005% ~ 0.030% of the calibration solution, with 4cm dish, see Table 2.
For arsenic content (mass fraction) of 0.030% ~ 0.100% of the calibration solution, with 1cm dish, see Table 3.
Table 2
Arsenic standard solution (4.11.3)
Volume/mL
Corresponding arsenic mass/μg
Sample content of arsenic (mass fraction) /%
0.10 g sample 0.50 g sample 1.00 g sample
0a 0 0 0 0
2.0 4 0.0004
4.0 8 0.008 0.0016 0.0008
6.0 12 0.012 0.0024
8.0 16 0.016 0.0032
10.0 20 0.020 0.004
15.0 30 0.030 0.006
a blank.
Table 3
Arsenic standard solution (4.11.2) Volume/mL Corresponding arsenic mass/μg
Sample content of arsenic (mass fraction) /%
0.10g sample
0a 0 0
2.0 20 0.020
4.0 40 0.040
6.0 60 0.060
8.0 80 0.080
10.0 100 0.100
a blank.
8 results indicated
8.1 Calculation method
Using the calibration curve (see 7.4), the absorbance of the test solution and blank solution is converted to the mass of arsenic (μg).
According to formula (1) calculate As, mass fraction (%) said.
As =
100 (1)
Where.
8.2 Precision
This part of the precision test consists of eight laboratories, nine levels of arsenic levels were measured, each laboratory for each level of arsenic
Measurement of 4 times.
Note 1. The first two of four determinations are performed under the repeatability conditions specified in GB/T 6379.1, ie by the same laboratory technician, using the same instrument, the same experiment
Conditions, the same calibration, measured in the shortest possible time.
Note 2. The third and fourth determination by the Note 1 Noteworthy staff, using the same instrument, at different times (different days), with a new calibration.
GB/T 223.31-2008/ISO 17058..2004
The samples used and the average values obtained are shown in Table A 2.
The results obtained were statistically analyzed according to GB/T 6379.1, GB/T 6379.2 and ISO 5725-3.
Table 4. The data diagram is given in Appendix B.
And the results obtained the next day, according to GB/T 6379.3 laboratory reproducibility limit (RW).
Table 4 Repeatability and reproducibility limit results
Reproducibility limit
RW R
0.00050 0.000178 0.000167 0.000184
0.00100 0.000267 0.000263 0.000313
0.00200 0.000400 0.000412 0.000532
0.00500 0.000682 0.000747 0.001072
0.01000 0.001022 0.001173 0.001823
0.02000 0.001531 0.001840 0.003098
0.05000 0.002611 0.003338 0.006248
0.10000 0.003911 0.005238 0.010620
9 test report
The test report should include the following.
a) Identification of materials, laboratory and analysis date;
b) to comply with the provisions of this section;
c) analysis results and their representation;
d) the anomalies observed in the assay;
e) Actions or optional actions that may have an impact on the analysis but are not covered by this section.
GB/T 223.31-2008/ISO 17058..2004
Appendix A.
(Informative)
International cooperation test additional information
The samples used are shown in Table A 1. The detailed results of the arsenic contents obtained in international cooperation tests are shown in Table A. 2.
Table A. 2 is the result of an international analysis of steel samples conducted in eight laboratories in three countries in.1999.
The test results are reported in the.2000 ISO /T C17/SC1N1272 document. Pictorial precision data in Appendix B.
Table A. 1 used sample
No. Sample As C Si Mn Cr Ni Others
1 NISTSRM2167 0.0005 0.051 0.026 0.022 0.0015 0.002 Cu0.0014; Sn0.006; Sb0.0020
2 GSBH41009-93 0.0010 3.89 1.58 0.65 0.0081 0.0058 Ti0.042; Sb0.00016
3 GSBH40107-96 0.0022 0.24 0.24 0.49 0.013 0.015 Cu 0.017
4 JSS169-7 0.005 0.047 0.21 0.42 (0.1) 0.046 Mo 0.068; Ti (0.01); Sn (0.01)
5 BCS461 0.011 0.082 0.44 0.64 15.20 5.16
6 NISTSRM50c 0.022 0.719 0.311 0.342 4.13 0.069 V1.16; W18.44
7 GB W01361 0.037 0.318 0.325 0.348 1.93 0.204
Mo1.19; V0.301; Sn0.014;
Sb0.0086
8 BCS453 0.052 0.210 0.36 - 0.24 0.114
Cu0.15; Sn0.019; Ti0.016;
W0.30
9 BYSC18201-94 0.092 0.076 1.64 1.10 0.013 0.025
Mo0.020; Nb0.012; Sn0.009;
Pb0.0038
Table A. 2 Detailed results of arsenic levels obtained from international cooperation tests
Numbered samples
Arsenic content (mass fraction) /% precision data
Approved value
Measured value Repeatability limit Reproducibility limit
1 NISTSRM2167 0.0005 0.000517 0.000500 0.000140 0.000181 0.000221
2 GSBH41009-93 0.0010 0.001000 0.000985 0.000349 0.000360 0.000302
3 GSBH40107-96 0.0022 0.001983 0.001983 0.000379 0.000198 0.000437
4 JSS169-7 0.005 0.00513 0.00519 0.000343 0.000469 0.000648
5 BCS461 0.011 0.0100 0.0103 0.002800 0.003757 0.002892
6 NISTSRM50c 0.022 0.0223 0.0222 0.001980 0.001771 0.004606
7 GB W01361 0.037 0.0374 0.03775 0.001617 0.002914 0.005879
8 BCS453 0.052 0.0540 0.0539 0.003130 0.003130 0.005099
9 BYSC18201-94 0.092 0.0907 0.0909 0.002800 0.004246 0.009116
珡 As1. the average of the same day;
珡 As2. the average of different days.
GB/T 223.31-2008/ISO 17058..2004
Appendix B
(Informative)
Precision data illustration
X --- arsenic content (mass fraction),%;
Y --- precision (mass fraction),%.
logRW = 0.65 log 珡 As2-1.6308
logR = 0.7654 log 珡 As1-1.2084
GB/T 223.31-2008/ISO 17058..2004
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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