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GB/T 21933.1-2008 English PDF (GBT21933.1-2008)

GB/T 21933.1-2008 English PDF (GBT21933.1-2008)

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GB/T 21933.1-2008: Ferronickel -- Determination of nickel content -- The dimethylglyoxime gravimetric method

GB/T 21933.1-2008
Ferronickel - Determination of nickel content - The dimethylglyoxime gravimetric method ICS 77.100
National Standards of People's Republic of China
GB/T 21933.1-2008/ISO 6352.1985
Determination of nickel, iron and nickel content
Diacetyl oxime gravimetric method
(ISO 6352.1985, IDT)
2008-05-30 released
Implementation of.2008-12-01
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Issued by China National Standardization Administration
This part of GB/T 21933 is equivalent to ISO 6352.1985 "Nickel-Iron---Determination of Nickel Content---Diacetyl Oxime Gravimetric Method." The technical content of this part is identical with ISO 6352.1985.For ease of use, this part has been modified as follows. a) The term "this International Standard" is changed to "this Part";
b) Use a decimal point "." to replace the comma "," as a decimal point in the English version; c) Delete the foreword of the international standard;
d) National standards are adopted for normative references.
Appendix A of this section is a normative appendix, and Appendix B is an informative appendix. This part was proposed by the China Iron and Steel Association.
This part is under the jurisdiction of the Metallurgical Industry Information Standards Institute. Drafting organization of this section. Shanxi Taigang Stainless Steel Co., Ltd. The main drafters of this section. Dai Xueqian, Wu Jing, Hu Jianchun.
GB/T 21933.1-2008/ISO 6352.1985
Determination of nickel, iron and nickel content
Diacetyl oxime gravimetric method
Warning. The personnel using this section should have practical experience in formal laboratory work. This section does not point out all possible security issues. The user is responsible for taking appropriate safety and health measures and ensuring compliance with the conditions stipulated by relevant national laws and regulations. 1 scope
This part of GB/T 21933 specifies the diacetyl oxime gravimetric method for the determination of nickel content in ferronickel. This section applies to the determination of nickel content in ferronickel, and the determination range (mass fraction). 15% to 60%. 2 Normative references
The clauses in the following documents have become clauses of this part by reference to this part of GB/T 21933.All dated quotations All subsequent amendments (excluding errata content) or revisions do not apply to this section, however, it is encouraged to reach The parties to the agreement study whether the latest versions of these documents can be used. For undated references, the latest version is applicable to this section.
GB/T 12805 Laboratory glass burette
GB/T 12806 Laboratory glass instrument single mark volumetric flask
GB/T 12808 single-marked pipette for laboratory glassware
GB/T 63779.1 Measurement methods and accuracy of results (accuracy and precision) Part 1.General principles and definitions (GB/T 63779.1- 2004, ISO 5725-1..1994, IDT)
GB/T 63779.2 Accuracy of measurement methods and results (accuracy and precision) Part 2.Determine the repeatability of standard measurement methods The basic method of performance and reproducibility (GB/T 6379.2-2004, ISO 5725-2.1994, IDT) GB/T 11415-1989 Laboratory sintered (porous) filter pore size, classification and designation 3 Principle
The sample is decomposed by nitric acid, and perchloric acid is dehydrated to precipitate silicon. After the silicon is removed by filtration, it is precipitated with diacetyl oxime ethanol solution in an ammoniacal tartrate medium. Nickel, after two precipitations, was dried and weighed at 150°C, and the residual nickel in the filtrate was determined by atomic absorption method. 4 Reagents and materials
Unless otherwise specified, only reagents and distilled water confirmed to be analytically pure or water of equivalent purity are used in the analysis. 4.1 Hydrochloric acid, ρ1.19g/mL.
4.2 Ammonia water, ρ0.925g/mL.
4.3 Nitric acid, ρ1.42g/mL.
4.4 Perchloric acid, ρ1.67g/mL.
4.5 Hydrofluoric acid, ρ1.13g/mL.
4.6 Acetic acid, ρ1.05g/mL.
4.7 Hydrochloric acid, 1+1.
4.8 Hydrochloric acid, 1+9.
4.9 Nitric acid, 1+1.
4.10 Acetic acid, 1+1.
GB/T 21933.1-2008/ISO 6352.1985
4.11 Hydrofluoric acid, 1+1.
4.12 Diacetyl oxime, 10g/L, ethanol solution.
4.13 Tartaric acid solution, 500g/L.
5 Instruments
Usually laboratory glassware, and the following instruments.
5.1 Filter crucible, sintered porous glass, pore size 10μm-20μm.
Note. Comply with the P16 specification specified in GB/T 11415-1989, or the commercially available G3 and G4 crucibles. 5.2 Glass beaker with a capacity of 600 mL.
5.3 The pipette, with a capacity of 50 mL and 100 mL, should comply with the Class A specified in GB/T 12808. 5.4 Volumetric flasks, with a capacity of.200ml and 1000ml, should comply with the level A specified in GB/T 12806. 5.5 Polytetrafluoroethylene (PTFE) beaker with a capacity of 600 mL, used for samples with high silicon content. 6 Take samples
6.1 The collection and preparation of laboratory samples shall be carried out in accordance with the agreed procedures. When there is a dispute, it shall be carried out in accordance with relevant national standards. 6.2 Laboratory samples are generally granular, drill chips or milling chips, and no further processing is required. 6.3 If the sample is contaminated by grease during grinding or drilling, it should be cleaned with analytical pure acetone and dried in air. 6.4 If the laboratory sample has a large difference in particle size, the sample size should be obtained after reduction. 7 Analysis steps
Warning 1.Perchloric acid fume is a strong oxidant and may cause an explosion when it encounters organic materials. All smoking processes should be suitable for use Carry out perchloric acid in a fume hood.
Warning 2.Hydrofluoric acid is a strong corrosive acid, which is very irritating and corrosive to the skin, and can cause extreme burns to the skin, which is difficult to heal. If it comes in contact with the skin, rinse immediately with water and seek medical attention. 7.1 The amount of sample
Weigh 4.0g sample, accurate to 0.001g.
7.2 Blank test
Carry out a blank test with the sample.
7.3 Preparation of the crucible
7.3.1 Put a mixture of 20mL hot hydrochloric acid (4.1), 10mL nitric acid (4.3), and 30mL water into a filter crucible (5.1) to filter, then Wash the acid substance on the crucible with warm water.
7.3.2 Place in an oven at 150°C to dry for 2 hours, cool in a desiccator for 60 minutes, and quickly weigh. Note 1.This process is suitable for processing new crucibles or cleaning old crucibles after analysis. Note 2.In order to improve accuracy, weighing crucibles and sediments should be carried out at the temperature and humidity as close as possible to the empty crucibles. 7.4 Preparation of test solution
7.4.1 Place the sample (7.1) in a 600ml beaker (5.2), add 25ml of water and 50ml of nitric acid (4.9) to decompose the sample, cover with a watch glass, Dissolve the sample (7.1) at low temperature and dissolve it as completely as possible. Note. If the nickel-iron content of silicon exceeds 1% (mass fraction), use a Teflon beaker (5.5), add 25mL water, 40mL nitric acid (4.9), and 10mL hydrochloric acid. (4.1) Treat the sample and boil slightly. In order to completely decompose the sample, add 10mL hydrofluoric acid (4.11), 40mL perchloric acid (4.4), and heat until the perchloric acid is emitted. Fume, cool, transfer all the solution to a glass beaker (5.2), heat until thick perchloric acid fume emerges, reflux at this temperature for 20 minutes, and then 7.4.2 "Remove the beaker from the electric furnace" operation.
7.4.2 After the sample is decomposed, add 40 mL of perchloric acid (4.4), heat it to emit thick perchloric acid fumes, reflux for 20 minutes at this temperature, remove and burn Cup, cool, add 20mL hydrochloric acid (4.1),.200mL hot water, filter the silicon with quantitative medium-speed filter paper, collect the filtrate in a 1,000mL volumetric flask, GB/T 21933.1-2008/ISO 6352.1985
Flush the beaker, rinse the silicon residue 3 times with hydrochloric acid (4.8), then wash it 4 times with hot water, discard the silicon residue, dilute to the mark with water, and mix well. 7.5 Determination
7.5.1 Use a pipette to transfer the test solution into a 600ml beaker (if the sample contains less than 30% nickel, aliquot 100ml of the solution, if it is higher than 30% Divide 50mL solution), make the amount of nickel in the solution be about 60mg~120mg, add water to about 300mL. 7.5.2 Add 10 mL of tartaric acid solution (4.13) to the 7.5.1 solution, and add ammonia (4.2) while stirring until the color of the solution changes from yellow Blue-green (pH value is slightly alkaline), the solution is always clear, slowly add sufficient amount of acetic acid (4.10) to restore the solution to yellow, the pH value must be Control between 4 and 5, and heat the solution to 60°C.
7.5.3 Add dimethylglyoxime (4.12) while stirring, about 4ml of dimethylglyoxime solution for every 10mg of nickel, and an excess of 20ml. 7.5.4 Add enough ammonia water to make the solution slightly alkaline (pH value is about 10), stir well for about 30 seconds, and let it stand for 30 minutes to precipitate Cohesion.
7.5.5 Filter the solution with medium-speed filter paper, wash the precipitate 5 times with warm water (40°C-50°C), retain the filtrate and perform the operation specified in 7.5.110. 7.5.6 Dissolve all the first sediment in the funnel with a hot mixture of 20mL hydrochloric acid (4.1), 10mL nitric acid (4.3) and 30mL water Dissolve into the original beaker, carefully wash the precipitate with 20 mL of mixed acid for 3 times, and wash it alternately with hot water to ensure that all the red precipitates are dissolved. Solution, and finally wash the filter paper thoroughly with hot water.
7.5.7 Re-precipitate nickel according to steps 7.5.2 to 7.5.4, using only 2mL tartaric acid solution (4.13) and excess 5mL diacetyl oxime solution (4.12).
7.5.8 Filter the precipitate with a dry and constant filter crucible (7.3.2), wash the beaker thoroughly, wash the precipitate with warm water 5 times, save the filtrate and press 7.5.10 processing.
7.5.9 Dry the crucible and precipitate in an oven at 150°C for 2h, cool in a desiccator for 60 minutes, and quickly weigh under the same conditions as 7.3.2. 7.5.10 Combine the filtrates from 7.5.5 to 7.5.8, and steam until viscous. About every 10ml to 15ml volume, add 50ml hydrochloric acid (4.1), Join in installments. Heat until the solution is clear, add 50 mL of hot water, boil, cool, transfer to a.200 mL volumetric flask, dilute with water to a minute Degree, mix well.
7.5.11 Use an atomic absorption spectrometer to determine the amount of nickel in the combined filtrate according to Appendix A. Note 1.The nickel content in the filtrate should not exceed 0.2% (mass fraction) of the nickel content of the original sample; Note 2.Excessive nickel in the filtrate indicates that the filter crucible is unqualified; Note 3.If the filtrate contains high nickel or the sensitivity of the atomic absorption analyzer is high, it is necessary to dilute the 7.5.10 filtrate before performing atomic absorption analysis. 8 Results presentation
8.1 Calculation
Calculate the mass fraction of nickel (%) according to formula (1).
f (1)
f---corrected value of nickel mass fraction in mixed filtrate;
20.32---Diacetyl oxime nickel is converted to 100 times the conversion factor of nickel. 8.2 Precision
8.2.1 Laboratory test This part has been tested by 39 analysts in 7 countries, 20 laboratories, and 8 samples with a nickel mass fraction of 21% to 41%. The samples are subjected to international comparison tests, and each laboratory provides the results of two independent analysts for each sample. GB/T 21933.1-2008/ISO 6352.1985 Test results are obtained by dividing 50 mL of test solution with (Ni) ≤ 30%, and 25 mL of test solution with (Ni)> 30%. The solution is finished After 7.5.1, overtake 100mL and 50mL, respectively, when using the prescribed method, the repeatability and reproducibility of this method may be better. 8.2.2 Statistical results
The repeatability and two reproducibility are calculated according to GB/T 6379.The calculation results are listed in Table 1.The inter-laboratory experiment report and statistical analysis are in Given in Appendix B.
Table 1 Statistical results
(Ni)/% 15~30 31~45
standard deviation
---The same analyst 狊W1
---Different analysts/same laboratory 狊W2
Different laboratories
Same laboratory reproducibility RW=2.83 S2W1+S2W2
The reproducibility of different laboratories R=2.83 S2W1+S2W2+S2Hb
Note 1.These repeatability and reproducibility results can be obtained by analyzing similar samples according to this method. Note 2.Repeatability and reproducibility data can be used as a guide to establish the error boundary. 9 Test report
The test report should include the following.
a) Identification of samples, laboratory and date of analysis, etc.;
b) The degree of compliance with the provisions of this section;
c) Analysis results and their representation;
d) Abnormal phenomena observed in the measurement;
e) Operations not included in this section that may have an impact on the analysis results, or optional operations. GB/T 21933.1-2008/ISO 6352.1985
Appendix A
(Normative appendix)
Determination of nickel content in combined filtrate by atomic absorption method A. 1 Summary
This appendix specifies the determination method for residual nickel in the combined filtrate after gravimetric determination of nickel. A. 2 Reagents
A. 2.1 Hydrochloric acid ρ1.19g/mL.
A. 2.2 Nickel standard solution
Weigh 1,000g of metallic nickel (accurate to 0.005g, (Ni)≥99.9%) in a 600mL beaker, add 40mL nitric acid (4.3) to dissolve Decompose, steam until viscous, cool, dissolve the salts with water, transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix well. This solution contains nickel 0.1g/L.
Draw 25.0 mL of the above solution, transfer it to a 250 mL volumetric flask, dilute to the mark with water, and mix. This standard solution contains nickel 0.1mg/mL.
A. 3 Apparatus
Common laboratory equipment and the following instruments.
A. 3.1 The burette, with a volume of 50 mL, with a minimum graduation of 0.05 mL, should comply with the level A specified in GB/T 12805. A. 3.2 Volumetric flasks, with a volume of.200ml, 250ml and 1000ml, should meet the level A specified in GB/T 12806. A. 3.3 The pipette, 25mL, should comply with the level A specified in GB/T 12808. A. 3.4 Atomic absorption spectrometer, equipped with air-acetylene burner and nickel hollow cathode lamp. A. 4 Operation steps
A. 4.1 Debugging of atomic absorption spectrometer
According to the requirements of the manufacturer’s instrument manual, use a nickel hollow cathode lamp at a wavelength of 232 nm to set the instrument of the atomic absorption spectrometer parameter.
Ignite the burner and adjust the flow of air and acetylene to obtain a stable and clear lean-burn flame when water is inhaled. A. 4.2 Preparation of calibration curve solution
Use a pipette to transfer 0, 2,000 mL, 5,000 mL, 10,000 mL, and 15,000 mL nickel standard solutions (A.2.2) into 5 respectively In a.200ml volumetric flask, add 50ml hydrochloric acid (A.2.1), dilute to the mark with water, and mix well. The nickel content of this calibration solution is. 0, 0.2mg, 0.5mg, 1.0mg and 1.5mg (see 7.5.10).
A. 4.3 Measurement
Start measuring the calibration solutions one by one with the zero solution as the reference, and record the absorbance value. Wash with water after each reading. Inhale Test solution (7.5.10) and record the absorbance value.
Repeat the measurement of the calibration solution and the test solution, during which the absorbance of the test solution is between the two calibration solutions. A. 4.4 Drawing of calibration curve
Draw a calibration curve based on the absorbance reading and the nickel content of the corresponding nickel calibration solution. A. 5 Results presentation
Using the calibration curve (A.4.4), the nickel content of the absorbance of the corresponding test solution can be found. GB/T 21933.1-2008/ISO 6352.1985
As described in 8.1, the nickel content f in the filtrate is expressed by mass fraction (%) and calculated according to formula (A.1). ×100 (A.1)
V --- The volume ratio of the solution.
Note 1.From the use of some atomic absorption instruments, the gain range of the photomultiplier tube can be adjusted appropriately if necessary; Note 2.There is no need to add diacetyl oxime to the standard solution, nor to steam until it becomes viscous; Note 3.If the nickel content in the filtrate is high, it should be properly diluted and corrected. GB/T 21933.1-2008/ISO 6352.1985
Appendix B
(Informative appendix)
Statistical reports of inter-laboratory tests
This part is an international comparison test conducted by 39 experimenters in 20 laboratories in 7 countries. For 8 pieces, the nickel content is between 21% and 41% (Mass score) between the commercial nickel-iron samples were analyzed. The purpose of the comparative test is to determine the repeatability according to the principle of GB/T 6379 And reproducibility within and between laboratories.
B. 1 Reference standards
ISO 3534 Statistics Vocabulary and Symbols
The precision of the ISO 5725 test method is determined by inter-laboratory tests for repeatability and reproducibility B. 2 Definition
For this appendix, the definition of ISO 3534 applies.
The item of reproducibility in the laboratory adds the content of the replacement of experimenter factors. B. 3 Design of the test plan
The purpose of this test plan is to provide as much information as possible. It is required that each laboratory have two experimenters on each sample Make a double analysis. In this way, for each laboratory, two sets of data are obtained for one sample. B. 4 Test sample
The eight ferronickel samples used in this experiment are all chips drilled or milled from the ingot. The milling chips are all pulverized with a vibration crusher. This The nickel content of these samples is between 21% and 41% (mass fraction), which represents the quality of commercial products. B. 5 Changes to the analysis program
During the test, when the nickel content is less than 30% (mass fraction), 25mL is divided into equal parts. After the completion of the test plan, the final decision to take Change to 100mL and 50mL (see 7.5.1).
B. 6 Statistical procedures
B. 6.1 Statistical test of outliers
B. 6.1.1 According to the recommendation of GB/T 6379, the Cochran test was used to compare the fluctuations of the experimenters themselves (the experimenters were Repeatability variance in double sample analysis). At a confidence level of 95%, 4 laboratories out of 3 samples were rejected. B. 6.1.2 The average fluctuation of experimenters in the laboratory is also compared in the same way. It is similar to the above procedure, except for the comparison factor. From "laboratory" to "laboratory", from "single measurement value" to "average measurement value of laboratory staff". When the confidence level is 95%, i...

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