GB/T 5120.2-1995 Chemical analysis of crude copper - Determination of arsenic content
Some standard content:
National Standard of the People's Republic of China
Methods for chemical analysis of blister copper-Determination of arsenic contentGB/T5120.2.- 995
Replaces GB5120.3-85
Part I Method 1 Hydride Generation-Atomic Fluorescence Spectrometry 1 Subject Content and Scope of Application
This standard specifies the method for the determination of arsenic content in blister copper. This standard is applicable to the determination of arsenic content in blister copper. Determination range: 0.02%~~0.15%. 2 Reference Standards
GB1.4 Guidelines for Standardization Work Provisions for the Preparation of Chemical Analysis Methods Standards GB1467 General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products GB4470 Terminology of Flame Emission, Atomic Absorption and Atomic Fluorescence Spectrometry 3 Summary of Methods
The sample is dissolved in dilute nitric acid. In a hydrochloric acid medium, pre-reduction is performed with thiourea-ascorbic acid. In an oxide generator, the fluorescence intensity is measured on an atomic fluorescence spectrometer, and the amount of arsenic is calculated according to the standard curve method. 4 Reagents
4.1 Hydrochloric acid (p1.19g/ml.).
4.2 Nitric acid (1+1).
4.3 Thiourea-ascorbic acid mixed solution: Weigh 5.0g of thiourea and ascorbic acid, dissolve them in water, dilute to 100mL, and mix well. 4.4 Potassium borohydride solution (10g/L): Weigh 5.0g of potassium borohydride, dissolve it in sodium hydroxide solution (2g/1.), and dilute it to 500mL with the sodium hydroxide solution, and mix well. Prepare it when needed. 4.5 Arsenic standard stock solution: weigh 0.1320g of standard arsenic trioxide (pre-dried at 100-105℃ for 1h, cooled to room temperature in a desiccator) in a 100ml beaker, add 5mL of sodium hydroxide solution (200g/1), heat at low temperature to dissolve, add 5mL of water, 2mL of ethanol solution (1g/L), neutralize with sulfuric acid (1+1) until the red color just disappears, then add 2mL in excess, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. 1mL of this solution contains 100μg of arsenic. 4.6 Arsenic standard solution: transfer 20.00mL of arsenic standard stock solution to a 50ml volumetric flask, dilute to scale with water, and mix. 1mL of this solution contains 4μg of arsenic.
5 Instruments
Atomic fluorescence spectrometer, with shielded quartz furnace atomizer, glass hydride generator and arsenic special hollow cathode lamp or high-intensity hollow cathode lamp. Approved by the State Administration of Technical Supervision on October 17, 1995 and implemented on March 1, 1996.
Fluorine gas: used as shielding gas and carrier gas. Www.bzxZ.net
GB/T5120.2-1995
Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Detection limit: not more than 9×10~1\g/ml. Precision: Use 0.1g/mL standard solution to measure the fluorescence intensity 10 times, and the standard deviation should not exceed 5.0% of the average fluorescence intensity.
See Appendix A (reference) for instrument working conditions. 6 Analysis steps
6.1 Test material
Weigh 0.25g of the sample to the nearest 0.0001g. Perform two independent determinations and take the average value. 6.2 Blank test
Perform a blank test with the test material.
6.3 Determination
6.3.1 Place the test material (6.1) in a 250mL beaker, add 10mL of nitric acid, cover with a watch glass, heat to completely dissolve it and evaporate until the volume of the solution is about 5mL, remove it, wash the watch glass and the wall of the beaker with water, cool to room temperature, transfer it to a 100mL volumetric flask, dilute to the mark with water, and mix well. 6.3.2 Transfer 5.00mL of the test solution (6.3.1) to a 100mL volumetric flask, add 40mL of water, 20mL of hydrochloric acid, and 10mL of sulfuric acid-ascorbic acid mixed solution, dilute to the mark with water, and mix well. 6.3.3 Transfer 2.00mL of the test solution (6.3.2) to the hydride generator and measure its fluorescence intensity according to the instrument operation procedure. Subtract the fluorescence intensity of the blank solution accompanying the sample and find the corresponding arsenic concentration from the working curve. 6.4 Drawing of the working curve
6.4.1 Transfer 0, 1.00, 2.00, 3.00, 4.00, 5.00mL of the arsenic standard solution to a set of 100mL volumetric flasks, add 40mL of water, 20mL of hydrochloric acid, and 10mL of thiourea-ascorbic acid mixed solution, dilute to the scale with water, and mix. 6.4.2 Under the same conditions as the test sample, measure the fluorescence intensity of the standard solution series, subtract the fluorescence intensity of the "zero" concentration solution, and draw the working curve with the concentration as the horizontal axis and the corresponding fluorescence intensity as the vertical axis. 7 Expression of analysis results
Calculate the percentage of chlorinated bicarbonate according to formula (1):
As(%) = cV× 10-6
Wherein: c—the concentration of chlorinated bicarbonate obtained from the working curve, ug/mL; V—-total volume of test solution, mL
--test solution fraction ratio
m—the mass of the test material, 8.
The result is expressed to two decimal places. If the content is less than 0.1%, it is expressed to three decimal places. 8 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 1. 178
0. 020- 0. 050
>0.050~0.10
>0.10~0. 15
9 Subject content and scope of application
GB/T 5120.2—1995
Part II Method 2 Potassium iodate titration method
This standard specifies the method for determining the arsenic content in crude copper. This standard is applicable to the determination of arsenic content in crude copper. Determination range: 0.15%~1.00%. 10 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods for metallurgical products 11 Summary of methods
The sample is decomposed by acid. In a 6 mol/L hydrochloric acid medium, potassium bromide is used as a catalyst and sulfuric acid is used to reduce pentavalent arsenic to trivalent arsenic. Arsenic trichloride is separated from other elements by distillation. After arsenic trichloride is condensed and absorbed by water, it is titrated with potassium bromate standard titration solution using methyl orange as an indicator until the red color of the solution disappears. 12 Reagents
12.1 Hydrazine sulfate.
12.2 Potassium bromide.
12.3 Hydrochloric acid (p1.19 g/mL).
12.4 Hydrochloric acid (1+1).
12.5 Nitric acid (1+1).
12.6 Sulfuric acid (1+1).
12.7 Arsenic standard solution: weigh 0.2641g of standard arsenic trioxide (pre-dried at 100~～105C for 1h, placed in a desiccator, and cooled to room temperature) in a 250mL beaker, add 20ml of sodium hydroxide solution (10g/L), heat at low temperature to dissolve. Remove and cool to room temperature. Add 100mL of water and 2 drops of phenolic acid ethanol solution (1g/L), neutralize with hydrochloric acid (1+5) until the red color disappears and 2 drops are in excess. Transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix. This solution contains 0.0002g of arsenic in 1mL. 12.8 Potassium bromate standard titration solution [c(1/6KBrO:）=0.005mol/L] 12.8.1 Preparation: Weigh 0.70g potassium bromate, place in a 250mL beaker, add a small amount of water and heat to dissolve, cool slightly, transfer to a reagent bottle, dilute to 5000mL with water, and mix well.
12.8.2 Calibration: Transfer 20.00mL of arsenic standard solution to three portions, place in 300mL beakers respectively, add 100ml of water and hydrochloric acid (12.3), heat to 60-70℃, add 2 drops of methyl orange indicator, and titrate with potassium bromate standard titration solution until the red color of the solution disappears as the end point. Perform a blank test together with the calibration.
Calculate the actual concentration of potassium bromate standard titration solution according to formula (2): 179
where: c
0. 037 46-
GB/T 5120.2---1995
(V,- V.) X 0. 037 46
actual concentration of potassium bromate standard titration solution, mol/L; -mass concentration of arsenic standard solution, g/mL; volume of arsenic standard solution added, mL;
the volume of potassium bromate standard titration solution consumed in titrating arsenic standard solution during calibration, mL; -the volume of potassium bromate standard titration solution consumed in titrating blank test solution during calibration, ml. The mass of arsenic equivalent to 1.00ml potassium bromate standard titration solution [c (1/6KBrO,)--1.00mol/L, g. The relative error of the three parallel calibration values is not greater than 0.2%, take the average value, otherwise recalibrate. 9 Methyl orange indicator (1g/L)
13 Instrument
The device for titration is shown in the figure below.
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Schematic diagram of titration device
1- Electric furnace (with voltage regulator); 2 Distillation flask (250ml.), 3 Mercury thermometer; 4 Glass catheter; 5 Condenser (spherical); 6 Absorption flask (250ml.) 14 Analysis steps
14.1 Sample
According to the arsenic content of the sample, weigh 0.5~1g of sample, accurate to 0.0001g. Conduct two tests independently and take the average value. 14.2 Blank test
Carry out a blank test with the sample.
·（2）
14.3 Determination
14.3.1 Place the sample (6.1) in a 250ml beaker, add 15ml nitric acid, cover with table blood, place on a hot plate and heat at low temperature until the sample is completely dissolved and the solution evaporates to about 10ml. Add 5ml sulfuric acid, heat to a solution volume of about 1ml, remove and cool slightly. Add 10ml hydrochloric acid (12.4) to dissolve the salts at low temperature. Remove, wash the table dish and the wall of the cup with water, and cool to room temperature. 14.3.2 Transfer the test solution into a 250ml distillation flask previously filled with 2g potassium bromide and 0.5g hydrazine sulfate, and add 35ml hydrochloric acid (12.3). 180
GB/T5120.2-1995
Wash the beaker with water, and add the washing liquid into the distillation flask to make the total volume of the solution about 80ml. Connect the distillation device and heat for distillation (strictly control the distillation temperature at 105-108). Collect the distillate in a 250ml absorption bottle pre-filled with 50ml of water. When the volume of the residual liquid in the distillation bottle is about one-third of the original volume, stop distillation and cool to room temperature. 14.3.3 Remove the distillation bottle and wash the inner wall of the condenser tube with 20-50ml of water. The washing liquid is put into the absorption bottle, heated to 60-70℃, 2 drops of methyl orange indicator are added, and the solution is titrated with potassium bromate standard titration solution until the red color disappears as the end point. 15 Expression of analytical results
Calculate the percentage of the content of the monument according to formula (3):
As(%) V+-Vo) × 0.037 46 × 100m.
Wherein: C\—-actual concentration of potassium bromate standard titration solution, mol/L; V,—the volume of potassium bromate standard titration solution consumed when titrating the sample solution during the determination, mL; V.——the volume of potassium bromate standard titration solution consumed when titrating the blank test solution during the determination, l.; me
0.037 46-
Mass of sample, g;
Mass of arsenic equivalent to 1.00mL of potassium bromate standard titration solution [c(1/6KBrO,)-1.00mol/1.] The result is expressed to two decimal places,
16 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
≥>0. 15 ~~ 0. 30
0.30~~0.60
0. 60～1. 00
GB/T 5120.2--1995
Appendix·A
Instrument working conditions
(reference)
Use AFS-220 dual-channel atom fluorescence spectrometer and special arsenic hollow cathode lamp, the working conditions of the measured quantity are as shown in Table A1: Table AI
Lamp current
Negative high voltage
Additional instructions:
Carrier gas flow
Shielding gas flow
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is revised by Dazhi Nonferrous Metals Corporation. This standard is revised by Dayezhi Nonferrous Metals Corporation. Atomization temperature
Liquid addition time
The main editors of this standard Method 1: Hu Junkai, Yuan Gongqi; Method 2: Chen Xianhui, Wang Lin. 182
Delay time
Sampling time
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