GB/T 20975.4-2020 English PDFUS$189.00 · In stock
Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 20975.4-2020: Methods for chemical analysis of aluminium and aluminium alloys - Part 4: Determination of iron content Status: Valid GB/T 20975.4: Historical versions
Basic dataStandard ID: GB/T 20975.4-2020 (GB/T20975.4-2020)Description (Translated English): Methods for chemical analysis of aluminium and aluminium alloys - Part 4: Determination of iron content Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: H12 Classification of International Standard: 77.120.10 Word Count Estimation: 10,159 Date of Issue: 2020-06-02 Date of Implementation: 2021-04-01 Older Standard (superseded by this standard): GB/T 20975.4-2008 Quoted Standard: GB/T 8005.2; GB/T 8170-2008 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration Summary: This standard specifies the determination of iron content in aluminum and aluminum alloys by phenanthroline spectrophotometry and potassium dichromate titration method. This standard applies to the arbitration determination of iron content in aluminum and aluminum alloys. Determination range of phenanthroline spectrophotometry: 0.0010%��3.50%; Determination range of potassium dichromate titration method: >3.50%��65.00%. GB/T 20975.4-2020: Methods for chemical analysis of aluminium and aluminium alloys - Part 4: Determination of iron content---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. Methods for chemical analysis of aluminium and aluminium alloys--Part 4.Determination of iron content ICS 77.120.10 H12 National Standards of People's Republic of China Replace GB/T 20975.4-2008 Chemical analysis methods of aluminum and aluminum alloys Part 4.Determination of iron content 2020-06-02 released Implementation on 2021-04-01 State Administration for Market Regulation Issued by the National Standardization Management Committee ForewordGB/T 20975 "Methods for Chemical Analysis of Aluminum and Aluminum Alloys" is divided into 37 parts. ---Part 1.Determination of mercury content; ---Part 2.Determination of arsenic content; ---Part 3.Determination of copper content; ---Part 4.Determination of iron content; ---Part 5.Determination of silicon content; ---Part 6.Determination of cadmium content; ---Part 7.Determination of manganese content; ---Part 8.Determination of zinc content; ---Part 9.Determination of lithium content by flame atomic absorption spectrometry; ---Part 10.Determination of tin content; ---Part 11.Determination of lead content; ---Part 12.Determination of titanium content; ---Part 13.Determination of vanadium content; ---Part 14.Determination of nickel content; ---Part 15.Determination of boron content; ---Part 16.Determination of magnesium content; ---Part 17.Determination of strontium content; ---Part 18.Determination of chromium content; ---Part 19.Determination of Zirconium Content; ---Part 20.Determination of Gallium Content Butyl Rhodamine B Spectrophotometry; ---Part 21.Determination of calcium content; ---Part 22.Determination of beryllium content; ---Part 23.Determination of antimony content; ---Part 24.Determination of total rare earth content; ---Part 25.Determination of element content by inductively coupled plasma atomic emission spectrometry; ---Part 26.Determination of carbon content by infrared absorption method; ---Part 27.Determination of cerium, lanthanum and scandium content by inductively coupled plasma atomic emission spectrometry; ---Part 28.Determination of cobalt content by flame atomic absorption spectrometry; ---Part 29.Determination of molybdenum content thiocyanate spectrophotometric method; ---Part 30.Determination of hydrogen content by heating extraction thermal conductivity method; ---Part 31.Determination of phosphorus content molybdenum blue spectrophotometric method; ---Part 32.Determination of Bismuth Content; ---Part 33.Determination of potassium content by flame atomic absorption spectrometry; ---Part 34.Determination of sodium content by flame atomic absorption spectrometry; ---Part 35.Determination of Tungsten Content Thiocyanate Spectrophotometric Method; ---Part 36.Determination of silver content by flame atomic absorption spectrometry; --- Part 37.Determination of Niobium Content. This part is Part 4 of GB/T 20975. This section was drafted in accordance with the rules given in GB/T 1.1-2009. This part replaces GB/T 20975.4-2008 "Methods for Chemical Analysis of Aluminum and Aluminum Alloys Part 4.Determination of Iron Content) Philippine Spectrophotometry. Compared with GB/T 20975.4-2008, the main technical changes in this part are as follows except for editorial changes. --- Added standard use safety warnings; --- Modify the "range" and increase the measurement range >3.50%~65.00% (see Chapter 1, Chapter 1 of the.2008 edition); --- Added "Normative Reference Documents" (see Chapter 2); --- Added "Terms and Definitions" (see Chapter 3); ---Modified the operation of different iron content in "Phenanthroline Spectrophotometry" and Table 1 (see 4.5.4.2,.2008 edition of 6.4.2); ---Modified the working curve of "Phenanthroline Spectrophotometry" (see 4.5.5.1, 6.5.1 in.2008 edition); ---Modified the precision of "Phenanthroline Spectrophotometry" (see Chapter 4.7, Chapter 8 of the.2008 edition); --- Added the "potassium dichromate titration method" (see Chapter 5); --- Deleted "Quality Assurance and Control" (see Chapter 9 of the.2008 edition); --- Added "Test Report" (see Chapter 6). This part was proposed by China Nonferrous Metals Industry Association. This part is under the jurisdiction of the National Nonferrous Metals Standardization Technical Committee (SAC/TC243). Drafting organizations of this section. Northeast Light Alloy Co., Ltd., Non-ferrous Metal Technology and Economic Research Institute, Guangxi Liuzhou Yinhai Aluminum Co., Ltd. Co., Ltd., China Aluminum Material Application Research Institute Co., Ltd., National Recycled Non-ferrous Metal Rubber and Plastic Materials Quality Supervision and Inspection Center, Hebei Stone New Materials Co., Ltd., Chinalco Ruimin Co., Ltd., Guangdong Guanglv Aluminum Profile Co., Ltd., and Youyan Yijin New Materials Co., Ltd. The main drafters of this section. Zhou Bing, Liu Xiandong, Xi Huan, Li Zhiyun, Luo Fen, Zhang Jine, Li Biao, Li Wei, Ma Yue, Liu Chang, Pan Biao, Liu Chaofang, He Minglan, Wang Wei, Lan Zheng, Han Xiao, Zhao Shengqiang, Cao Juncheng. The previous versions of the standards replaced by this part are as follows. ---GB/T 6987.4-1986, GB/T 6987.4-2001; ---GB/T 20975.4-2008. Chemical analysis methods of aluminum and aluminum alloys Part 4.Determination of iron content Warning---Personnel using this section should have practical experience in formal laboratory work. This section does not point out all possible safety issues question. 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 ScopeThis part of GB/T 20975 specifies the phenanthroline spectrophotometric method and potassium dichromate titration method for the determination of iron in aluminum and aluminum alloys. content. This section applies to the arbitration determination of iron content in aluminum and aluminum alloys. Phenanthroline spectrophotometric determination range. 0.0010%~ 3.50%; determination range of potassium dichromate titration method. >3.50%~65.00%.2 Normative referencesThe following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated references, the latest version (including all amendments) applies to this document. GB/T 8005.2 Terminology of Aluminum and Aluminum Alloy Part 2.Chemical Analysis GB/T 8170-2008 Numerical rounding rules and the expression and determination of limit values3 Terms and definitionsThe terms and definitions defined in GB/T 8005.2 apply to this document.4 Phenanthroline spectrophotometry4.1 Method summary The sample is dissolved in hydrochloric acid and hydrogen peroxide, and the iron is reduced with hydroxylamine hydrochloride. The pH of the test solution is controlled to be 3.5-4.5, so that the divalent iron ions and the adjacent Phenanthroline forms a stable orange-red complex, and its absorbance is measured at a wavelength of 510.0nm with a spectrophotometer to determine the iron content. 4.2 Reagents Unless otherwise stated, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis. 4.2.1 Hydrogen peroxide (ρ=1.10g/mL). 4.2.2 Hydrochloric acid (5 1). 4.2.3 Hydrochloric acid (1 1). 4.2.4 Sodium hydroxide solution (200g/L), stored in plastic bottles. 4.2.5 Hydroxylamine hydrochloride solution (10g/L). 4.2.6 Phenanthroline solution (2.5g/L). Weigh 2.5g of phenanthroline (C12H8N2·H2O) or 3g of phenanthroline hydrochloride (C12H8N2·HCl·H2O) dissolved in warm water and cooled. Dilute to 1000mL with water and mix well. 4.2.7 Nickel chloride (NiCl2·6H2O) solution (1g/L). 4.2.8 Buffer solution. Weigh 272g of sodium acetate (CH3COONa·3H2O) and dissolve it with 500mL of water. After filtering, add 240mL of ice. Acetic acid (ρ=1.05g/mL), dilute to 1000mL with water, and mix well. 4.2.9 Mixed solution. Combine hydroxylamine hydrochloride solution (4.2.5), o-phenanthroline solution (4.2.6) and buffer solution (4.2.8) to (1 1 3) The product is mixed with each other and stored in a brown bottle. The storage period does not exceed four weeks. 4.2.10 Iron standard storage solution. Use a certified standard solution for preparation first. Or weigh 0.2860g of Ozone which has been burnt at 600℃ in advance Ferric fluoride [w(Fe2O3)≥99.99%], put in a.200mL beaker, add 30mL hydrochloric acid (4.2.3), heat to completely dissolve, cool, Transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix. 1mL of this solution contains 0.2mg iron. 4.2.11 Iron standard solution A. Pipette 25.00mL iron standard stock solution (4.2.10) into a 100mL volumetric flask and dilute to the mark with water. Mix well (prepared when used). 1mL of this solution contains 0.05mg iron. 4.2.12 Iron standard solution B. Pipette 25.00mL iron standard stock solution (4.2.10) into a 500mL volumetric flask and dilute to the mark with water. Mix well (prepared when used). This solution 1mL contains 0.01mg iron. 4.3 Apparatus Spectrophotometer. 4.4 Sample Process the sample into chips not larger than 1mm. 4.5 Analysis steps 4.5.1 Sample According to Table 1, weigh the sample (4.4) of the corresponding mass (m0) to the nearest 0.0001g. 4.5.2 Parallel experiment Do two tests in parallel and take the average value. 4.5.3 Blank test Do a blank test with the sample (4.5.1). 4.5.4 Determination 4.5.4.1 Place the test material (4.5.1) in a 250mL beaker, cover with a watch glass, add 25mL of hydrochloric acid (4.2.3) in batches, and wait vigorously. After the reaction, add 7 to 8 drops of hydrogen peroxide (4.2.1), if it is a pure aluminum sample, add a nickel chloride solution (4.2.7), and slowly heat until the sample is complete Dissolve completely, boil for 5 minutes, and cool. Aluminum alloys that are not easily dissolved by hydrochloric acid or have high silicon content can be dissolved in alkali. Place the sample (4.5.1) in In a 100mL silver beaker (or polytetrafluoroethylene beaker), carefully add 20mL of sodium hydroxide solution (4.2.4), and cover with a silver watch (or polytetrafluoroethylene). Vinyl fluoride cover), heat until the sample is completely dissolved, if the mass fraction of silicon in the sample is ≥4.00%, keep the test solution at a temperature slightly lower than the boiling point 20min, carefully add the amount of water lost due to evaporation, boil for 2min~3min, wash the cup wall and watch dish with water, and dilute the test solution to about 25mL, add 20mL hydrochloric acid (4.2.2), boil slightly until the solution is clear, and cool. 4.5.4.2 When the iron mass fraction is 0.0010%~0.050%, transfer the sample solution (4.5.4.1) into a 100mL volumetric flask, if not The soluble matter is filtered with medium-speed quantitative filter paper, and the precipitate is washed with hot water. When the iron mass fraction >0.050%~3.50%, the sample solution (4.5.4.1) Transfer to the corresponding volumetric flask (V0), if there is insoluble matter, filter with medium-speed quantitative filter paper, wash the precipitate with hot water, and dilute with water to Mark, mix, and then pipette the corresponding volume (V1) of the solution in a 100mL volumetric flask. 4.5.4.3 In a 100mL volumetric flask, add 25mL mixed solution (4.2.9), dilute to the mark with water, and mix. Leave it for 30 minutes. If When the mass fraction of copper in the sample is ≥5.0% or the mass fraction of zinc is ≥4.0% or the mass fraction of nickel is ≥2.0%, or the combined mass fraction of copper, zinc, and nickel ≥5%, add 25mL mixed solution (4.2.9), then add 20mL o-phenanthroline solution (4.2.6) (when drawing the working curve, also Correspondingly add 20mL o-phenanthroline solution), dilute to the mark with water, and mix. Leave it for 30 minutes. 4.5.4.4 Move part of the sample solution (4.5.4.3) into the absorption tank, and take the blank test (4.5.3) as a reference. At spectrophotometer wavelength The absorbance was measured at 510.0nm. Find the corresponding iron mass (m1) from the working curve. 4.5.5 Drawing of working curve 4.5.5.1 According to the mass fraction of iron in the sample, the preparation of the series of standard solutions is divided into the following two types. a) When the iron mass fraction is 0.0010%~0.010%. pipette 0mL, 1.00mL, 2.00mL, 5.00mL, 8.00mL, 10.00mL iron standard solution B (4.2.12), put them in a set of 100mL volumetric flasks, dilute to about 50mL, add 25mL mixed solution (4.2.9), dilute to the mark with water, and mix. Leave for 30min; b) When the iron mass fraction is >0.010%~3.50%. pipette 0mL, 1.00mL, 2.00mL, 4.00mL, 6.00mL, 8.00mL iron standard solution A (4.2.11), put them in a set of 100mL volumetric flasks, dilute to about 50mL, add 25mL mixed solution (4.2.9), dilute to the mark with water, and mix. Leave it for 30 minutes. 4.5.5.2 Move part of the series of standard solutions (4.5.5.1) into the absorption tank, and use the reagent blank solution (without iron standard solution) as the reference, and The absorbance was measured at a wavelength of 510.0nm with a spectrophotometer. Use iron mass as the abscissa and absorbance as the ordinate to draw the working curve. 4.6 Processing of test data The iron content is calculated as the mass fraction of iron wFe, calculated according to formula (1). When the iron mass fraction is less than 1.00%, the calculation result retains two significant digits; when the iron mass fraction is ≥1.00%, the calculation result is expressed as small Count the last two digits. Numerical rounding is implemented in 3.2 and 3.3 of GB/T 8170-2008. 4.7 Precision 4.7.1 Repeatability The measured value of two independent test results obtained under repeatability conditions, within the average range given below, the two test results The absolute difference does not exceed the repeatability limit r, and the case of exceeding the repeatability limit r does not exceed 5%. Repeatability limit r uses linear interpolation according to the data in Table 2 Method or extension method. 4.7.2 Reproducibility The measured values of two independent test results obtained under reproducibility conditions, within the average range given below, the two test results The absolute difference does not exceed the reproducibility limit R, and the case of exceeding the reproducibility limit R does not exceed 5%. Reproducibility limit R According to the data in Table 3, the linear internal Obtained by interpolation or extension method.5 Potassium dichromate titration method5.1 Method summary In an acidic solution, use potassium dichromate standard titration solution to directly titrate ferrous ions, and excess potassium dichromate will refer to sodium diphenylamine sulfonate. The indicator is oxidized to purple, which is the end point, and the iron content is determined by this. 5.2 Reagents Unless otherwise stated, only reagents and laboratory tertiary water confirmed to be analytically pure are used in the analysis. 5.2.1 Ammonium fluoride solution (100g/L). 5.2.2 Sulfuric acid-phosphoric acid mixed acid. In 300mL sulfuric acid (13), slowly add 10mL phosphoric acid (ρ=1.69g/mL), and mix well. 5.2.3 Potassium dichromate standard titration solution (c=0.015mol/L). Weigh 4.4130g and dry it in an electric oven at 120℃ ± 2℃ Constant amount of working standard reagent potassium dichromate (relative molecular weight 294.186), placed in a 300mL beaker, dissolved in water, and transferred to 1000mL In a volumetric flask, dilute to the mark with water and mix well. 5.2.4 Sodium diphenylamine sulfonate indicator solution (4g/L). 5.3 Specimen Process the sample into chips not larger than 1mm. 5.4 Analysis steps 5.4.1 Sample Weigh the mass (m) as 0.50g sample (5.3), accurate to 0.0001g. 5.4.2 Parallel test Do two tests in parallel and take the average value. 5.4.3 Determination 5.4.3.1 Place the sample (5.4.1) in a 400mL beaker, add 15mL ammonium fluoride solution (5.2.1), 30mL sulfuric acid-phosphoric acid mixed acid (5.2.2), heat until the sample is completely dissolved, and cool. 5.4.3.2 When the iron mass fraction is 3.50% ~ 40.00%, filter the sample solution (5.4.3.1) with filter paper (or absorbent cotton) in 500 mL In the conical beaker, wash the precipitate 6 to 7 times, and dilute the sample solution to about 150 mL. When the mass fraction of iron is >40.00%~65.00% At the time, filter the sample solution (5.4.3.1) with filter paper (or absorbent cotton) in a 250mL volumetric flask (V2), wash the precipitate 6 to 7 times, dilute with water Release to the mark and mix well. The aliquot volume (V3) is 50.00mL sample solution in a 500mL conical beaker, add 15mL sulfuric acid-phosphoric acid mixture Synthetic acid (5.2.2), diluted to about 150mL. 5.4.3.3 Add 2 to 4 drops of sodium diphenylamine sulfonate indicator solution (5.2.4), and titrate to the solution with potassium dichromate standard titration solution (5.2.3) A steady purple color is the end point. Record the volume (V) of the potassium dichromate standard titration solution (5.2.3) consumed. 5.5 Processing of test data The iron content is calculated as the mass fraction of iron wFe, calculated according to formula (2). The calculation result is expressed to two decimal places. The rounding of values shall be implemented in 3.2 and 3.3 of GB/T 8170-2008. 5.6 Precision 5.6.1 Repeatability The measured value of two independent test results obtained under repeatability conditions, within the average range given below, the two test results The absolute difference does not exceed the repeatability limit r, and the case of exceeding the repeatability limit r does not exceed 5%. Repeatability limit r uses linear interpolation according to the data in Table 4 Method or extension method. 5.6.2 Reproducibility The measured values of two independent test results obtained under reproducibility conditions, within the average range given below, the two test results The absolute difference does not exceed the reproducibility limit R, and the case of exceeding the reproducibility limit R does not exceed 5%. Reproducibility limit R is linear within Obtained by interpolation or extension method.6 Test reportThe test report should give at least the following aspects. a) The number, name and method used in this section; b) All necessary information about identification of samples, laboratory, analysis date, report date, etc.; c) Express the test results in an appropriate form; d) Abnormal phenomena during the test; e) Signatures of review and approval personnel. ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 20975.4-2020_English be delivered?Answer: Upon your order, we will start to translate GB/T 20975.4-2020_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB/T 20975.4-2020_English with my colleagues?Answer: Yes. 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