GB/T 5121.11-1996 Chemical analysis methods for copper and copper alloys - Determination of chromium content
Some standard content:
1 Scope
National Standard of the People's Republic of China
Chemical analysis methods for copper and copper alloys--Determination of zinc content Copper and copper alloys--Determination of zinc content Part I Method 1 Determination of zinc content by flame atomic absorption spectrometry This standard specifies the method for determination of zinc content in copper and copper alloys. GB/T5121.11-1996
Replaces GB6121.1185
GB 6520. 986
GB 8002. 6
GB 8002. 7
GB 8550.9
This standard applies to the determination of zinc content in copper and copper alloys. Determination range: 0.0020% to 2.00%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB1.4-88 Standardization work guidelines for chemical analysis methods GB1467-78 General principles for chemical analysis methods for metallurgical products and: General provisions GB7728-87 General principles for chemical analysis of metallurgical products Flame atomic absorption spectrometry 3 Method summary
The sample is dissolved with nitric acid or nitric acid plus nitric acid and fluoric acid or hydrochloric acid plus hydrogen peroxide. Using air-acetylene flame, the atomic absorption spectrometer measures the absorbance of zinc at a wavelength of 213.8nm. When preparing the standard solution series, add the corresponding amount of copper to eliminate the interference of the matrix copper: other elements present in the alloy do not interfere with the determination. 4 Reagents
4.1 Hydrofluoric acid (pl.13g/mL).
4.2 Hydrogen peroxide (30%).
4.3 Hydrochloric acid (1+1).
4.4 Nitric acid (1+1).
4.5 Boric acid solution (40 g/L).
4.6 Copper solution: Weigh 10g pure copper (zinc content less than 0.0001%) and place it in a 500ml beaker, add 70ml nitric acid (4.4). Heat to dissolve completely, boil to remove nitrogen oxides, and cool. Transfer to a 500ml volumetric flask, dilute to scale with water, and mix well. This solution contains 20mg copper in 1ml.
4.7 Zinc standard stock solution: Weigh 0.5000g pure zinc and place it in a 250ml beaker, add 10ml nitric acid (4.4). Heat to dissolve completely, boil to remove nitrogen oxides, and cool. Transfer to a 1000ml volumetric flask, dilute to scale with water, and mix well. This solution contains 500ug zinc in 1ml.
4.8 Zinc standard solution: Pipette 20.00mL zinc standard storage solution (4.7) into a 500ml volumetric flask, add 10ml nitric acid (4.4), dilute to scale with water, and mix. This solution contains 20μg zinc in 1mL. Approved by the State Administration of Technical Supervision in 199611-04
Implementation in 199704-01
5 Instruments
Original absorption spectrometer, with zinc core cathode lamp GB/F 5127. 11 --- 7996
Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Sensitivity: The characteristic concentration of zinc in a solution that is consistent with the selected sample solution should not be greater than 0.(1/ml. Precision: When the absorbance is measured 10 times with the standard solution of the highest concentration, the standard deviation should not exceed 1.0 of the average absorbance; when the absorbance is measured 10 times with the standard solution of the lowest concentration (not the "zero" standard solution), its standard deviation should not exceed 0.5% of the average absorbance of the standard solution of the highest concentration.
Linearity of working curve: Divide the working curve into five sections according to concentration. The ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section should not be less than 0.85.
Instrument working conditions are shown in Appendix A (Suggested Appendix). 6 Analysis steps
6.1 Test sample
Weigh the sample according to Table 1. Accurate to 0.0001g. Table 1
Address, %
0. 002 0~-0. 010
0. 010-~0. 080
20.080~~0.40
+0. 40~- 2. 00
Carry out two independent determinations and take the average value. 6.2 Empty self-test
6.2.1 Perform self-test with the sample.
Total volume of solution, ml
Pipette solution volume.ml.
6.2.2 When the zinc content is not more than 0.08%, weigh a similar amount of pure copper as in the sample (the zinc content should be less than 0.0001%). Perform empty self-test with the sample.
6.3 Determination
6.3.1 Place the sample (6.1) in a false In a 150ml beaker, add 10mL nitric acid, heat to dissolve completely, boil to remove nitrogen oxides, cool. When the sample contains tin radicals of 0.5%, place sample (6.1) in a 150ml beaker, add 10ml hydrochloric acid and drop peroxide until the sample is completely dissolved, boil to remove excess peroxide, and cool. When the sample contains silicon of 0.5% or contains nitric acid insoluble matter, leave sample (6.1) in a 150ml polytetrafluoroethylene beaker, add 10ml nitric acid and 3-5 drops of fluoride acid. Heat to dissolve completely. Boil to remove nitrogen oxides. Add 10 ml of boric acid solution. Mix. Cool. 6.3.1.1 When the zinc content is less than 0.08%, transfer the solution (6.3.1) to a 100 ml volumetric flask, dilute to scale with water, and mix. 6.3.1.2 When the zinc content is greater than 0.08%, transfer the solution (6.3.1) according to Table 1 to the corresponding test bottle, dilute to scale with water, and mix. Transfer 10.00 ml of the test solution to a 100 ml volumetric flask, add 5 ml of nitric acid, and dilute to scale with water. Dilute to the scale and mix well. 6.3.2 Use air acetylene flame, atomic absorption spectrometer wavelength 213.8nm, and zero with water at the same time as the standard solution series, and measure the absorbance of the solution. Subtract the absorbance of the air solution accompanying the sample from the measured absorbance, and find the corresponding zinc concentration from the working curve. 6.4 Drawing of the working curve
6.4.7 Preparation of standard solution series
6.4.1.1 The zinc concentration is 0.0020%-0.010%2.19
GB/T 5121. 11-1996
Put 0, 1.00, 2.00, 3.00, 4.00, 5.00 ml of zinc standard solution into a set of 100 ml bottles, add 50.00 ml of copper solution and 5 ml of nitric acid, and dilute to the mark with water. Mix 6.4.1.2 If the zinc content is greater than 0.010%~0.080%, take 0, 1.00, 2.00, 4.00, 6.00, 8.00 ml of zinc standard solution. 6.4.1.3 If the zinc content is greater than 0.080%~0.40%, take 0.1.00, 2.00, 3.00, 4.00, 5.00ml of zinc standard solution and place it in a group of 100ml volumetric bottles. Add 1.2ml of copper solution and 5ml of nitric acid, dilute to the scale with water, and mix. 6.4.1.4 If the zinc content is greater than 0.40%~~2.00%, take 0.1.00, 2.00, 3.00, 4.00, 5.00ml of zinc standard solution and place it in a group of 100ml volumetric bottles. Add 1.00ml of copper solution and 5ml of nitric acid, dilute to the scale with water, and mix. 6.4.2 Use air-acetylene flame, F atomic absorption spectrometer at wavelength 213.8nm, adjust to zero with water. Measure the absorbance of the solution (6.1.1.1 or 6.4.1.2 or 6.4.1.3 or 6.4.1.4). Subtract the absorbance of the "zero" concentration solution in the standard solution series, and draw a working curve with zinc concentration as the horizontal axis and absorbance as the vertical axis. 7 Expression of analysis results
Calculate the percentage of zinc according to formula (1):
Zn(%) CV. - V. × 10-
Where; c is the zinc concentration of the sample solution obtained from the T curve·g/mL; V, is the total volume of the test solution, mL.
V. is the volume of the diluted aliquot, mL; V, is the volume of the aliquot of the test solution, mL;
mo is the mass of the sample, 8.
The results are expressed to two decimal places. If the zinc content is less than 0.10%, it is expressed to three decimal places; if it is less than 0.010%, it is expressed to four decimal places.
8 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Qiu 2. Table 2
0.0020~0.0050
>0. 005 0~0.015
>0.015~0.050
>0. 050~0. 15
0. 15~0.50
>0. 50~2. 00
9Scope
GB/T5121.111996
Part II Method 24-Methyl-pentanone-2 Extraction and separation Na2EDTA titration method for determination of zinc content This standard specifies the method for determination of zinc content in copper and copper alloys. This standard is applicable to the determination of zinc content in copper and copper alloys. Determination range: 2.00%~6.00%, 10 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB1.4-88 Standardization work guidelines for chemical analysis method standards GB1467-78 General principles and general provisions for chemical analysis methods for metallurgical products 11 Method summary
Zinc (II) and thiocyanate form complex anions in dilute hydrochloric acid medium, which are extracted and separated with 4-methyl-pentanone-2 to remove most of the interfering elements. In the hexamethylenetetramine buffer solution, a masking agent is added and monocresol orange is used as an indicator. Sodium ethylenediaminetetraacetate (CHN,O,Na?·2HO) standard solution is dripped.
12 Reagents
12.14 Methyl-pentanone-2.
12.2 Hydrogen peroxide (30%).
12.3 Hydrofluoric acid (pl.13g/ml.).
12.4 Hydrochloric acid (1+1).
12.5 Thiourea solution (100g/L).
12.6 Ammonium fluoride solution (200g/1.). Store in a plastic bottle. 12.7 Ammonium sulfate solution (500g/L).
12.8 Xylenol orange solution (2g/1.).
12.9 Buffer solution: Weigh 150g hexamethylenetetramine and dissolve it in water, add 30mL hydrochloric acid (12.1). Dilute to 500ml with water. Mix 12.10 Washing solution: Take 10mL ammonium thiourea solution (12.7), add 4mL hydrochloric acid (12.4 ), add water to 100ml., mix with a spoon 12.11 Zinc standard solution: weigh 0.5000g pure zinc and place it in a 150mL beaker, add 10ml hydrochloric acid (12.4) to dissolve, cool, transfer to a 500mL volumetric flask, dilute to scale with water and mix. This solution contains 1mg zinc per ml. 12.12 Disodium ethylenediaminetetraacetate (CHuN,OgNaz·2H,O) standard titration solution Ec (C1,HN0Na:·2H0) = 0.01mol/LJ.
12.12.1 Preparation
Weigh 7.445g disodium ethylenediaminetetraacetate (CH,NOgNa·2Hz0) and dissolve in about 200ml hot water t, Transfer to a 2000ml volumetric flask, dilute to the mark with water, and mix. 12.12.2 Calibration
Put 10.00ml zinc standard solution (12.11) in a 250ml beaker, add about 70ml water, 20ml buffer solution (12.9), 3-5 drops of xylenol orange solution (12.8), and titrate with disodium ethylenediaminetetraacetic acid (CmHi,N0Na2·2H,O) standard titration solution (12.12.1) until the solution changes from purple-red to yellow. Calculate the actual concentration of disodium ethylenediaminetetraacetic acid (CHNONa2·2H) standard titration solution according to formula (2): 251
Where: r-
GB/T 5121. 11 - 1996
VX 0.065 38
-The actual concentration of disodium ethylenediaminetetraacetate (CH,N,O,Na2·2H,O) standard titration solution, mol/l.; V,---The volume of disodium ethylenediaminetetraacetate (CH,NzNa·2H.O) standard titration solution consumed during calibration, mL-The mass of zinc equivalent to 1.00mL disodium ethylenediaminetetraacetate (CH,N.Na2HO) standard titration solution [cC.HNOAa: 0. 065 38-
2H0) = 1.000mol/1.]·g/mol Take 3 portions for calibration. The volume of disodium ethylenediaminetetraacetate (C.HNO.Na2·2HO) standard titration solution consumed during calibration should not exceed 0.10mL. Take the average value. Otherwise, recalibrate. 13 Analysis steps
13.1 Test sample
Weigh 0.200g of test sample, accurate to 0.0001g. Perform two independent determinations and take the average value. 13.2 Determination
13.2.1 Place the test sample (13.1) in a 150mL beaker, add 10ml of hydrochloric acid and 2~3ml of hydrogen peroxide, and dissolve completely with slight heat. Boil to remove excess hydrogen peroxide and cool. If the silicon content of the test sample is not less than 0.5%, place the test sample (13.1) in a 150mL polytetrafluoroethylene beaker, add 10ml of hydrochloric acid and 2~3mL of hydrogen peroxide, and dissolve with slight heat. When the test sample is basically dissolved, add 2~3 drops of hydrofluoric acid and continue to dissolve completely. Boil to remove excess hydrogen peroxide and cool. 13.2.2 Transfer the solution into a 125mL separatory funnel. Add 10mL of ammonium fluoride solution (if turbidity occurs, add 4mL of hydrochloric acid) and 40mL of thiourea solution, add water to about 70mL, and mix well. Add 10mL of ammonium thiocyanate solution, 20mL of 4-methyl-pentanone-2, shake for 2 minutes, let stand to separate, and discard the aqueous phase.
13.2.3 Add 15mL of washing liquid and 5mL of ammonium fluoride solution to the organic phase, shake for 30s, let stand to separate, and discard the aqueous phase. 13.2.4 Transfer the organic phase into a 250ml beaker, wash the separatory funnel with 50ml water, merge the washing liquid into the main solution, add 20ml buffer solution, stir vigorously for 1min, add 5ml ammonium fluoride solution, 5ml thiophene solution and 3-5 drops of xylenol orange solution, and titrate with disodium ethylaminetetraacetic acid (CHN2O.Na2·2H2O) standard titration solution until the solution changes from red to yellow. 14 Expression of analysis results
Calculate the percentage of zinc according to formula (3):
Zn(%) - :Vi× 0.065 38 ×100m
Wherein: c—actual concentration of disodium ethylenediaminetetraacetic acid (C,H1,N,O.Naz·2H,O) standard titration solution, mol/1.; V,——volume of disodium ethylenediaminetetraacetic acid (Ci.HN,O.Naz·2H,O) standard titration solution consumed during the determination, mL; m——mass of the sample, g. bzxz.net
The obtained result shall be expressed to two decimal places.
15 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 3. Table 3
>2.00~3.50
3.50~6.00
GB/T5121:11—1996
(Appendix of Suggestions)
Instrument Working Conditions
Use Hitachi 508 Atomic Absorption Spectrometer to determine the amount of zinc. The working conditions are as shown in Table A1Table A1
Input 0.18 Output 0.182 Hydrogen peroxide (30%).
12.3 Hydrofluoric acid (pl.13g/ml.).
12.4 Hydrochloric acid (1+1).
12.5 Thiourea solution (100g/L).
12.6 Ammonium fluoride solution (200g/1.). Store in a plastic bottle. 12.7 Ammonium sulfate solution (500g/L).
12.8 Xylenol orange solution (2g/1.).
12.9 Buffer solution: Weigh 150g hexamethylenetetramine and dissolve it in water, add 30mL hydrochloric acid (12.1). Dilute with water to 500ml. Mix. 12.10 Washing solution: Take 10mL ammonium thiourea solution (12.7), add 4mL hydrochloric acid (12.4), add water to 100ml. Mix. 12.11 Zinc standard solution: Weigh 0.5000g pure zinc and place it in a 150mL beaker, add 10ml hydrochloric acid (12.4) to dissolve, cool, transfer to a 500mL volumetric flask, dilute with water to the mark. Mix. This solution contains 1mg zinc in 1ml. 12.12 Disodium ethylenediaminetetraacetate (CHuN,OgNaz·2H,O) standard titration solution Ec (C1,HN0Na:·2H0) = 0.01mol/LJ.
12.12.1 Preparation
Weigh 7.445 g of disodium ethylenediaminetetraacetate (CH,NOgNa·2Hz0) and dissolve it in about 200 ml of hot water. Transfer it into a 2000 ml volumetric flask, dilute to the mark with water and mix well. 12.12.2 Calibration
Pipette 10.00 ml zinc standard solution (12.11) into a 250 ml beaker, add about 70 ml water, 20 ml buffer solution (12.9), 3-5 drops of xylenol orange solution (12.8), and titrate with disodium ethylenediaminetetraacetic acid (CmHi,N0Na2·2H,O) standard titration solution (12.12.1) until the solution changes from purple-red to yellow. Calculate the actual concentration of disodium ethylenediaminetetraacetic acid (CHNONa2·2H) standard titration solution according to formula (2): 251
Where: r-
GB/T 5121. 11 - 1996
VX 0.065 38
--The actual concentration of disodium ethylenediaminetetraacetate (CH,N,O,Na2·2H,O) standard titration solution, mol/l.; V, ---The volume of disodium ethylenediaminetetraacetate (CH,NzNa·2H.0) standard titration solution consumed during calibration, mL-The mass of zinc equivalent to 1.00mL disodium ethylenediaminetetraacetate (CH,N.Na2HO) standard titration solution [cC.HNOAa: 0. 065 38—
2H0) = 1.000mol/1.]·g/mol Take 3 portions for calibration, and the volume of disodium ethylenediaminetetraacetate (C.HNO.Na2·2HO) standard titration solution consumed during calibration should not exceed 0.10mL, and take the average value. Otherwise, recalibrate. 13 Analysis steps
13.1 Test sample
Weigh 0.200g of test sample, accurate to 0.0001g. Perform two independent determinations and take the average value. 13.2 Determination
13.2.1 Place the test sample (13.1) in a 150mL beaker, add 10ml of hydrochloric acid and 2~3ml of hydrogen peroxide, and dissolve completely with slight heat. Boil to remove excess hydrogen peroxide and cool. If the silicon content of the test sample is not less than 0.5%, place the test sample (13.1) in a 150mL polytetrafluoroethylene beaker, add 10ml of hydrochloric acid and 2~3mL of hydrogen peroxide, and dissolve with slight heat. When the test sample is basically dissolved, add 2~3 drops of hydrofluoric acid and continue to dissolve completely. Boil to remove excess hydrogen peroxide and cool. 13.2.2 Transfer the solution into a 125mL separatory funnel. Add 10mL of ammonium fluoride solution (if turbidity occurs, add 4mL of hydrochloric acid) and 40mL of thiourea solution, add water to about 70mL, and mix well. Add 10mL of ammonium thiocyanate solution, 20mL of 4-methyl-pentanone-2, shake for 2 minutes, let stand to separate, and discard the aqueous phase.
13.2.3 Add 15mL of washing liquid and 5mL of ammonium fluoride solution to the organic phase, shake for 30s, let stand to separate, and discard the aqueous phase. 13.2.4 Transfer the organic phase into a 250ml beaker, wash the separatory funnel with 50ml water, merge the washing liquid into the main solution, add 20ml buffer solution, stir vigorously for 1min, add 5ml ammonium fluoride solution, 5ml thiophene solution and 3-5 drops of xylenol orange solution, and titrate with disodium ethylaminetetraacetic acid (CHN2O.Na2·2H2O) standard titration solution until the solution changes from red to yellow. 14 Expression of analysis results
Calculate the percentage of zinc according to formula (3):
Zn(%) - :Vi× 0.065 38 ×100m
Wherein: c—actual concentration of disodium ethylenediaminetetraacetic acid (C,H1,N,O.Naz·2H,O) standard titration solution, mol/1.; V,——volume of disodium ethylenediaminetetraacetic acid (Ci.HN,O.Naz·2H,O) standard titration solution consumed during the determination, mL; m——mass of the sample, g.
The obtained result shall be expressed to two decimal places.
15 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 3. Table 3
>2.00~3.50
3.50~6.00
GB/T5121:11—1996
(Appendix of Suggestions)
Instrument Working Conditions
Use Hitachi 508 Atomic Absorption Spectrometer to determine the amount of zinc. The working conditions are as shown in Table A1Table A1
Input 0.18 Output 0.182 Hydrogen peroxide (30%).
12.3 Hydrofluoric acid (pl.13g/ml.).
12.4 Hydrochloric acid (1+1).
12.5 Thiourea solution (100g/L).
12.6 Ammonium fluoride solution (200g/1.). Store in a plastic bottle. 12.7 Ammonium sulfate solution (500g/L).
12.8 Xylenol orange solution (2g/1.).
12.9 Buffer solution: Weigh 150g hexamethylenetetramine and dissolve it in water, add 30mL hydrochloric acid (12.1). Dilute with water to 500ml. Mix. 12.10 Washing solution: Take 10mL ammonium thiourea solution (12.7), add 4mL hydrochloric acid (12.4), add water to 100ml. Mix. 12.11 Zinc standard solution: Weigh 0.5000g pure zinc and place it in a 150mL beaker, add 10ml hydrochloric acid (12.4) to dissolve, cool, transfer to a 500mL volumetric flask, dilute with water to the mark. Mix. This solution contains 1mg zinc in 1ml. 12.12 Disodium ethylenediaminetetraacetate (CHuN,OgNaz·2H,O) standard titration solution Ec (C1,HN0Na:·2H0) = 0.01mol/LJ.
12.12.1 Preparation
Weigh 7.445 g of disodium ethylenediaminetetraacetate (CH,NOgNa·2Hz0) and dissolve it in about 200 ml of hot water. Transfer it into a 2000 ml volumetric flask, dilute to the mark with water and mix well. 12.12.2 Calibration
Pipette 10.00 ml zinc standard solution (12.11) into a 250 ml beaker, add about 70 ml water, 20 ml buffer solution (12.9), 3-5 drops of xylenol orange solution (12.8), and titrate with disodium ethylenediaminetetraacetic acid (CmHi,N0Na2·2H,O) standard titration solution (12.12.1) until the solution changes from purple-red to yellow. Calculate the actual concentration of disodium ethylenediaminetetraacetic acid (CHNONa2·2H) standard titration solution according to formula (2): 251
Where: r-
GB/T 5121. 11 - 1996
VX 0.065 38
--The actual concentration of disodium ethylenediaminetetraacetate (CH,N,O,Na2·2H,O) standard titration solution, mol/l.; V, ---The volume of disodium ethylenediaminetetraacetate (CH,NzNa·2H.0) standard titration solution consumed during calibration, mL-The mass of zinc equivalent to 1.00mL disodium ethylenediaminetetraacetate (CH,N.Na2HO) standard titration solution [cC.HNOAa: 0. 065 38—
2H0) = 1.000mol/1.]·g/mol Take 3 portions for calibration, and the volume of disodium ethylenediaminetetraacetate (C.HNO.Na2·2HO) standard titration solution consumed during calibration should not exceed 0.10mL, and take the average value. Otherwise, recalibrate. 13 Analysis steps
13.1 Test sample
Weigh 0.200g of test sample, accurate to 0.0001g. Perform two independent determinations and take the average value. 13.2 Determination
13.2.1 Place the test sample (13.1) in a 150mL beaker, add 10ml of hydrochloric acid and 2~3ml of hydrogen peroxide, and dissolve completely with slight heat. Boil to remove excess hydrogen peroxide and cool. If the silicon content of the test sample is not less than 0.5%, place the test sample (13.1) in a 150mL polytetrafluoroethylene beaker, add 10ml of hydrochloric acid and 2~3mL of hydrogen peroxide, and dissolve with slight heat. When the test sample is basically dissolved, add 2~3 drops of hydrofluoric acid and continue to dissolve completely. Boil to remove excess hydrogen peroxide and cool. 13.2.2 Transfer the solution into a 125mL separatory funnel. Add 10mL of ammonium fluoride solution (if turbidity occurs, add 4mL of hydrochloric acid) and 40mL of thiourea solution, add water to about 70mL, and mix well. Add 10mL of ammonium thiocyanate solution, 20mL of 4-methyl-pentanone-2, shake for 2 minutes, let stand to separate, and discard the aqueous phase.
13.2.3 Add 15mL of washing liquid and 5mL of ammonium fluoride solution to the organic phase, shake for 30s, let stand to separate, and discard the aqueous phase. 13.2.4 Transfer the organic phase into a 250ml beaker, wash the separatory funnel with 50ml water, merge the washing liquid into the main solution, add 20ml buffer solution, stir vigorously for 1min, add 5ml ammonium fluoride solution, 5ml thiophene solution and 3-5 drops of xylenol orange solution, and titrate with disodium ethylaminetetraacetic acid (CHN2O.Na2·2H2O) standard titration solution until the solution changes from red to yellow. 14 Expression of analysis results
Calculate the percentage of zinc according to formula (3):
Zn(%) - :Vi× 0.065 38 ×100m
Wherein: c—actual concentration of disodium ethylenediaminetetraacetic acid (C,H1,N,O.Naz·2H,O) standard titration solution, mol/1.; V,——volume of disodium ethylenediaminetetraacetic acid (Ci.HN,O.Naz·2H,O) standard titration solution consumed during the determination, mL; m——mass of the sample, g.
The obtained result shall be expressed to two decimal places.
15 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 3. Table 3
>2.00~3.50
3.50~6.00
GB/T5121:11—1996
(Appendix of Suggestions)
Instrument Working Conditions
Use Hitachi 508 Atomic Absorption Spectrometer to determine the amount of zinc. The working conditions are as shown in Table A1Table A1
Input 0.18 Output 0.182.1 Place the sample (13.1) in a 150mL beaker, add 10ml hydrochloric acid, 2~3ml hydrogen peroxide, dissolve completely with slight heat. Boil to remove excess hydrogen peroxide, and cool. If the sample contains silicon content of not less than 0.5%, place the sample (13.1) in a 150mL polytetrafluoroethylene beaker, add 10ml hydrochloric acid, 2~3ml hydrogen peroxide, dissolve with slight heat, and when the sample is basically dissolved, add 2~3 drops of hydrofluoric acid and continue to dissolve completely. Boil to remove excess hydrogen peroxide, and cool. 13.2.2 Transfer the solution to a 125mL separatory funnel. Add 10mL ammonium fluoride solution (if turbidity occurs, add 4ml hydrochloric acid) 40mL thiourea solution, add water to about 70mL, and mix. Add 10ml ammonium thiocyanate solution, 20ml 4-methyl-pentanone-2, shake for 2 minutes, let stand and separate, and discard the aqueous phase.
13.2.3 Add 15 ml of washing liquid and 5 ml of ammonium fluoride solution to the organic phase, shake for 30 seconds, let stand and separate the layers, and then discard the aqueous phase. 13.2.4 Transfer the organic phase to a 250 ml beaker, wash the separatory funnel with 50 ml of water, add the washing liquid to the main solution, add 20 ml of buffer solution, stir vigorously for 1 min, add 5 ml of ammonium fluoride solution, 5 ml of thiophene solution and 3 to 5 drops of xylenol orange solution, and titrate with disodium ethylaminetetraacetic acid (CHN2O.Na2·2H2O) standard titration solution until the solution changes from red to yellow. 14 Expression of analysis results
Calculate the percentage of zinc according to formula (3):
Zn(%) - :Vi× 0.065 38 ×100m
Wherein: c—actual concentration of disodium ethylenediaminetetraacetic acid (C,H1,N,O.Naz·2H,O) standard titration solution, mol/1.; V,——volume of disodium ethylenediaminetetraacetic acid (Ci.HN,O.Naz·2H,O) standard titration solution consumed during the determination, mL; m——mass of the sample, g.
The obtained result shall be expressed to two decimal places.
15 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 3. Table 3
>2.00~3.50
3.50~6.00
GB/T5121:11—1996
(Appendix of Suggestions)
Instrument Working Conditions
Use Hitachi 508 Atomic Absorption Spectrometer to determine the amount of zinc. The working conditions are as shown in Table A1Table A1
Input 0.18 Output 0.182.1 Place the sample (13.1) in a 150mL beaker, add 10ml hydrochloric acid, 2~3ml hydrogen peroxide, dissolve completely with slight heat. Boil to remove excess hydrogen peroxide, and cool. If the sample contains silicon content of not less than 0.5%, place the sample (13.1) in a 150mL polytetrafluoroethylene beaker, add 10ml hydrochloric acid, 2~3ml hydrogen peroxide, dissolve with slight heat, and when the sample is basically dissolved, add 2~3 drops of hydrofluoric acid and continue to dissolve completely. Boil to remove excess hydrogen peroxide, and cool. 13.2.2 Transfer the solution to a 125mL separatory funnel. Add 10mL ammonium fluoride solution (if turbidity occurs, add 4ml hydrochloric acid) 40mL thiourea solution, add water to about 70mL, and mix. Add 10ml ammonium thiocyanate solution, 20ml 4-methyl-pentanone-2, shake for 2 minutes, let stand and separate, and discard the aqueous phase.
13.2.3 Add 15 ml of washing liquid and 5 ml of ammonium fluoride solution to the organic phase, shake for 30 seconds, let stand and separate the layers, and then discard the aqueous phase. 13.2.4 Transfer the organic phase to a 250 ml beaker, wash the separatory funnel with 50 ml of water, add the washing liquid to the main solution, add 20 ml of buffer solution, stir vigorously for 1 min, add 5 ml of ammonium fluoride solution, 5 ml of thiophene solution and 3 to 5 drops of xylenol orange solution, and titrate with disodium ethylaminetetraacetic acid (CHN2O.Na2·2H2O) standard titration solution until the solution changes from red to yellow. 14 Expression of analysis results
Calculate the percentage of zinc according to formula (3):
Zn(%) - :Vi× 0.065 38 ×100m
Wherein: c—actual concentration of disodium ethylenediaminetetraacetic acid (C,H1,N,O.Naz·2H,O) standard titration solution, mol/1.; V,——volume of disodium ethylenediaminetetraacetic acid (Ci.HN,O.Naz·2H,O) standard titration solution consumed during the determination, mL; m——mass of the sample, g.
The obtained result shall be expressed to two decimal places.
15 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 3. Table 3
>2.00~3.50
3.50~6.00
GB/T5121:11—1996
(Appendix of Suggestions)
Instrument Working Conditions
Use Hitachi 508 Atomic Absorption Spectrometer to determine the amount of zinc. The working conditions are as shown in Table A1Table A1
Input 0.18 Output 0.18
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