GB/T 5121.7-1996 Chemical analysis methods for copper and copper alloys - Determination of nickel content

This standard specifies the method for measuring the arsenic content in copper and copper alloys. This standard is applicable to the determination of arsenic content in copper and copper alloys. Determination range: 0.0010% to 0.10%. GB/T 5121.7-1996 Chemical analysis method for copper and copper alloys Determination of nickel content GB/T5121.7-1996 Standard download decompression password: www.bzxz.net

1 Scope
National Standard of the People's Republic of China
Chemical analysis method for copper and copper alloys
Determination of arsenic content
Copper and copper alloys--Determination of arsenic content This standard specifies the method for determining the arsenic content in copper and copper alloys. GB/T 5121.7---1996
Replaces GB5121.78
G13 5122. 16
GI36520.886
GRB 8550. 15
This standard is applicable to the determination of arsenic content in copper and copper alloys. Determination range: 0.0010%~~0.10%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. The versions shown are valid at the time of publication of this standard. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB1.4--88 Standardization Guidelines for Chemical Analysis Methods Standard Code and Regulations GB1467-78 General Principles and General Regulations for Chemical Analysis Methods of Metallurgical Products GB7729-87 General Principles for Chemical Analysis of Metallurgical Products Spectrophotometric Method 3 Method Summary
The sample is dissolved with mixed acid or nitric acid. Sodium hypobromite or potassium permanganate is used to oxidize arsenic (II) to arsenic (V), which reacts with molybdate to form arsenomolybdenum heteropoly acid, which is extracted with a mixture of n-butanol and ethyl acetate, and reduced to molybdenum blue with stannous chloride. Its absorbance is measured at a wavelength of 730nm on a spectrophotometer. To prevent the interference of silicon, add hydrochloric acid to evaporate to dryness to dehydrate the silicic acid and filter it out. When the iron content is high, add the corresponding iron to the blank solution to offset its influence. Copper and other elements coexisting in copper and gold do not interfere with the determination. 4 Reagents
4.1 n-butanol.
4.2 Hydrochloric acid (pl.19 g/ml.).
4.3 Mixed acid: Mix 2 units of nitric acid (1+1) with 1 unit of hydrochloric acid (1+1). 4.4 Nitric acid (1+1).
4.5 Hydrochloric acid (1+1).
4.6 Nitric acid [c(HNO,) 1.8 mol/L]. 4.7 Nitric acid c(HNO,) --- 0.9 mol/L]4.8 Hydrochloric acid [c(HCI) = 1.8 moi/L]. 4.9 Hydrochloric acid [c(HCI) = 0.9 mol/L]. 4.10 Sodium hypobromite solution: Mix 50 mL of saturated bromine water with 100 mL of sodium hydroxide solution (10 g/L). 4.11 Ammonium molybdate solution (50g/L): Weigh 5g ammonium molybdate [(NH,)Mo,0214H.O] and place in a 150ml beaker, add 90mL water, heat to dissolve, and cool. Dilute with water to 100mL and mix. 4.12 n-Butanol-trichloromethane mixture: 1 unit volume of n-butanol and 3 units of trifluoromethane are mixed. n-Butanol-ethyl acetate mixture: n-Butanol and ethyl acetate are mixed in equal volumes. 4.13
4.14 Potassium permanganate solution (10g/1.). Approved by the State Administration of Technical Supervision on November 4, 1996 228
Implemented on April 1, 1997
GB/T5121.7: 1996
4.15 Stannous chloride solution (10 mmol/L): Weigh 1.0g of stannous chloride (SnCl.*2H)), add 20ml of 4.5% sulphuric acid, heat to dissolve, and cool. Dilute with water to 100ml and mix. Prepare on the same day. 4.16 Iron solution: weigh (.2000g pure iron (arsenic content less than 0.001%), add 10ml hydrochloric acid (4.5), add 2~3ml hydrogen peroxide (30%) dropwise, dissolve completely with slight heat, boil to remove excess hydrogen peroxide. Cool. Transfer to a 200mL volumetric flask, dilute to scale with water, and mix well. This solution contains 1mg iron per ml.
4.17 Arsenic standard stock solution: weigh 0.1320g standard arsenic oxide that has been pre-dried at 100~110C for 2h and cooled in a desiccator to room temperature, add 1 0ml sodium hydroxide solution (100g/L), heat to dissolve, and cool. Transfer to a 1000ml volumetric flask, add water to 200~300ml, add 2 drops of phenol ethanol solution (10g/1.) Neutralize with nitric acid (4.4) until the solution changes from red to colorless and pass 10ml. Dilute to scale with water and mix. This solution contains 0.1mg arsenic in 1ml. 4.18 Arsenic standard solution: Transfer 10.00ml. Arsenic standard stock solution to a 100ml volumetric flask, dilute to scale with water, mix. This solution contains 10 μg.
5 Instruments
Spectrophotometer. bzxz.net
6 Analysis steps
6.1 Sample
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Content, %
0.0010-~0.004 0
> 0. 004 0~0. 015
0. 01 ~0.040
>0.040~~0.10
Sample g
Carry out two independent determinations and take the average value. 6.2 Blank test
6.2.1 Carry out a blank test with the sample.
Total volume of test solution, ml.
Take the volume of test solution. ml.
6.2.2 When analyzing silicon bronze, transfer the iron solution so that the amount of iron is close to that in the sample. Carry out a blank test with the sample. 6.3 Determination
6.3.1 Place the sample (6.1) in a 150ml beaker, add 10mL of mixed acid, heat to dissolve and evaporate to 2~3ml, and cool. Add 10ml of hydrochloric acid (4.8) to dissolve the salts.
6.3.1.1 When the content of nitrite is not more than 0.04% , transfer the solution into a 125mL separatory funnel, wash the beaker with 20mL hydrochloric acid (4.9) in batches, add the washing liquid into the main solution, add 2mL sodium hypobromite solution, mix well. Let stand for 5min. The following is carried out according to 6.3.4~6.3.8. 6.3.1.2 When the arsenic content is greater than 0.04%, transfer the solution (6.3.1) into a 100mL volumetric flask ± 1 with hydrochloric acid (4.8), dilute to the scale. Mix well. According to Table 1, transfer the test solution into a 125mL separatory funnel, add 20mL hydrochloric acid (4.9), 2mL sodium hypobromite solution. Mix well. Let stand for 5min. The following is carried out according to 6.3.4~6.3.8. 6.3.2 When analyzing silicon bronze, place the sample (6.1) in a 150mL beaker, add 10mL mixed acid, heat to dissolve and evaporate to below, and cool. Add 5ml hydrochloric acid (4.2), evaporate to , and cool. Add 5ml hydrochloric acid (4.2), evaporate to +, and cool. Add 10ml hydrochloric acid (4.8), heat to dissolve salts. Filter with quantitative filter paper into a 125ml separatory funnel, wash the beaker and precipitate with 20ml hydrochloric acid (4.9) in batches, and add the washing liquid into the main liquid! , Add 2ml sodium hypobromate solution, and mix well. Let stand for 5min, and proceed as follows 6.3.1 to 6.3.8.229
GB/T 5121.7--1996
6.3.3 When analyzing silver and copper, place the sample (6.1) in a 150ml beaker, add 10ml nitric acid (4.4), heat to dissolve and evaporate to 2~3ml, and cool. Add 10 mL of nitric acid (4.6) to dissolve the salts, transfer to a 125 mL separatory funnel, wash the beaker with 20 mL of nitric acid (4.7) in batches, add the washing solution to the main solution, drop potassium permanganate solution until it remains slightly red, mix well. Let stand for 5 minutes. Follow 6.3.4 to 6.3.8 for the rest.
6.3.4 Add 5 mL of ammonium molybdate solution to the test solution (6.3.1.1 or 6.3.1.2 or 6.3.2 or 6.3.3), mix well. Let stand for 5 minutes. Add 2 mL of n-butanol and shake to dissolve it in the aqueous phase. 6.3.5 Add 15mL of n-butanol-chloroform mixture, shake for 30 seconds, let stand and separate, then discard the organic phase. Add 10mL of n-butanol-chloroform mixture to the aqueous phase, shake for 30 seconds, let stand and separate, then discard the organic phase. Repeat the extraction several times until all phosphorus is removed (add a few drops of tin dichloride solution to the separated organic solution. If it does not turn blue, it means that all phosphorus has been removed). 6.3.6 Add 5mL of hydrochloric acid (4.5) to the solution. Add 4mL of nitric acid (4.4) to the silver solution and mix well. Add 20mL of n-butanol-ethyl acetate mixture, shake for 1 minute, let stand and separate, then discard the aqueous phase. 6.3.7 Add 20mL of nitric acid (4.6) to the organic phase, shake for 30 seconds, let stand and separate, then discard the aqueous phase. Repeat as before. 6.3.8. Add 10mL of stannous chloride solution to the organic phase, shake for 30s, let stand to separate, and then remove the aqueous phase. Transfer the organic phase to a dried 25ml volumetric flask, dilute to scale with n-butanol, and mix well. 6.3.9 Pipette a portion of the test solution into a 1cm (2cm for 0.5g of sample) absorbent tube, and measure its absorbance at a wavelength of 730nm on a spectrophotometer using the blank solution accompanying the sample as a reference. Find the corresponding arsenic amount from the working curve. 6.4 Drawing of working curve
6.4.1 Pipette 0, 0.50, 1.00, 1.50, 2.00, 2.50 or 0, 1.00, 2.00, 3.00, 4.00, 5.00mL of arsenic standard solution into a set of 125mL separating funnels, add 20mL of hydrochloric acid (4.8) to each, add water to 30mL, add 2mL of sodium hypobromite solution, mix, and let stand for 5min. The following shall be carried out according to 6.3.4 to 6.3.8. 6.4.2 Pipette part of the test solution into 2cm (or 1cm) absorbent tube, use the reagent blank as reference, measure its absorbance at a wavelength of 730nm on the spectrophotometer, and draw the working curve with the arsenic amount as the horizontal axis and the absorbance as the vertical axis. 7 Expression of analysis results
Calculate the percentage of arsenic according to formula (1):
As(%) = mi V. × 10-
Wherein: m-the amount of the work curve, ugV. Total volume of test solution, mL;
V, the volume of the test solution, mL;
mo the mass of the sample, g.
The result is expressed to two decimal places. If the arsenic content is less than 0.10%, it is expressed to 3 decimal places; if it is less than 0.010%, it is expressed to 4 decimal places.
8 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 001 0~0. 003 0
>0. 003 0~ 0. 007 0
0. 007 0~0. 015
>0. 015~~0. 030
>0.030~0.060
>0. 060~0. 10
GB/T 5121. 7.--7996
Table 2 (End)
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