This standard specifies the method for determining the lead content in copper concentrate. This standard is applicable to the determination of lead content in copper concentrate. GB/T 3884.7-2000 Chemical analysis method for copper concentrate Determination of lead content GB/T3884.7-2000 Standard download decompression password: www.bzxz.net

GB/T3884.7—2000
This standard is a reconfirmation of GB/T3884.8—1983 "Chemical analysis method for copper concentrate - determination of lead content by EDTA volumetric method", and only its determination range is adjusted, that is, from 2.00% to 10.00% to >5.00% to 13.00%. This standard complies with:
GB/T1.1—1993 Guidelines for standardization work Unit 1: Rules for drafting and expressing standards 1 Part 1: Basic provisions for standard writing
GB/T1.4—1988 Guidelines for standardization work Rules for the preparation of chemical analysis methods GB/T1467—1978 General principles and general provisions for chemical analysis methods for metallurgical products GB/T17433—1998 Basic terminology for chemical analysis of metallurgical products This standard replaces GB/T3884.8-1983 from the date of implementation. This standard is proposed by the State Bureau of Nonferrous Metals Industry. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard is drafted by Daye Nonferrous Metals Company. This standard is drafted by Tongling Nonferrous Metals (Group) Company. The main drafters of this standard are Shao Conghe, Li Shasha and Feng Deyin. 37
1 Scope
National Standard of the People's Republic of China
Chemical Analysis Methods of Copper Concentrates
Determination of Lead Content
Methods for chemical analysis of copper concentratesDetermination of lead contentThis standard specifies the method for determination of lead content in copper concentrates. This standard is applicable to the determination of lead content in copper concentrates. Determination range: >5.00%~13.00%. 2 Principle of the method
GB/T3884.7-2000
Replaces GB/T3884.8—1983
The sample is decomposed with acid to precipitate lead into lead sulfate. Filter to separate it from the coexisting elements; add acetic acid-sodium acetate buffer solution to dissolve the lead sulfate. At pH 5.0-6.0, use xylenol orange as an indicator and titrate with Na,EDTA standard titration solution. Calculate the amount of lead from the volume of NaEDTA standard titration solution consumed.
3 Reagents
3.1 Ascorbic acid.
3.2 Anhydrous ethanol.
3.3 Hydrochloric acid (p1.19g/mL).
3.4 ​​Perchloric acid (pl.67g/mL).
3.5 Sulfuric acid (1+24).
3.6 Sulfuric acid (1+49).
3.7 Nitric acid and sulfuric acid: Mix 7 parts of nitric acid (pl.42g/mL) with 3 parts of sulfuric acid (p1.84g/mL). 3.8 Ammonia water (1+1).
3.9 Buffer solution (pH 5.5) Dissolve 150g of anhydrous sodium acetate in water, add 50mL of acetic acid, dilute to 1000mL with water, and mix. Xylenol orange indicator (5g/L).
3.11 Potassium thiocyanate solution (50g/L).
3.12. Lead standard solution: Weigh 1.0000g of metallic lead (99.99%) in a 250mL beaker, add 20mL of nitric acid (1+1), cover with blood, place on a hot plate, heat at low temperature to dissolve, and after complete dissolution, boil to drive off nitrogen oxides, remove, and cool to room temperature. Transfer to a 500mL volumetric flask, add 10mL of nitric acid (1+1), dilute to scale with water, and mix. This solution contains 2mg of lead in 1mL. 3.13 Disodium ethylenediaminetetraacetic acid (NazEDTA) standard titration solution (0.01 mol/L) 3.13.1 PreparationbZxz.net
Weigh 3.7 g NaEDTA (CiHNONa·2H,O) into a 500 mL beaker, add hot water to dissolve, cool, transfer to a 1000 mL volumetric flask, dilute to the mark with water, and mix well. 3.13.2 Calibration
Pipette three portions of 25.00 mL of the lead standard solution (3.12) and place them in 300 mL beakers respectively. Add 50 mL of water and 2 drops of xylenol orange indicator (3.10). Neutralize with ammonia water (3.8) until it turns slightly red. Add 30 mL of buffer solution (3.9) and titrate with Na2EDTA standard titration solution (3.13) until the solution changes from orange-red to bright yellow. This is the end point. Calculate the actual concentration of the Na-EDTA standard titration solution according to formula (1): co.V
Wherein: c—-actual concentration of the Na-EDTA standard titration solution, mol/LConcentration of the lead standard solution, mg/mL;
—molar mass of lead, g/mol;
V. Volume of the lead standard solution transferred, mL; V,—volume of the NaEDTA standard titration solution consumed in titrating the lead standard solution during calibration, mL. (1)
Take the average of the three calibration results. The extreme value of the three calibration results should not be greater than 4X10-5mol/L. Otherwise, recalibrate. 4 Samples
4.1 The sample particle size should not be greater than 0.082mm
4.2 The sample should be dried at 100~105℃ for 1h and then placed in a desiccator to cool to room temperature. 5 Analysis steps
5.1 Test material
Weigh 0.25g of test material to the nearest 0.0001g. Perform two independent determinations and take the average value. 5.2 Blank test
Perform a blank test with the test material.
5.3 Determination
5.3.1 Place the test material (5.1) in a 300mL beaker, moisten it with a small amount of water, add 10mL of hydrochloric acid, cover it with a watch glass, place it on a hot plate and heat it for several minutes, remove it and cool it slightly. Add 10mL of nitric and sulfuric acid mixture, heat and evaporate it until it is almost dry, remove it and cool it slightly (if the sample has a high carbon content, add 2~3mL of pernitrogen acid and continue to evaporate it until it is almost dry).
5.3.2 Add 50mL of sulfuric acid (3.5) along the wall of the beaker, boil it for several minutes to dissolve the soluble salts, cool it, add 10mL of anhydrous ethanol, and let it stand for 1h.
5.3.3 Filter with slow quantitative filter paper. Wash the precipitate several times with sulfuric acid (3.6) until the filtrate is free of red color when checked with potassium thiocyanate solution. Finally, wash the precipitate once with water and discard the filtrate. 5.3.4 Blow the precipitate into the original beaker with water, add 30mL buffer solution, cover with Table III and boil. After the lead sulfate is completely dissolved, immerse the filtrate in the solution, continue to boil for several minutes, and cool. 5.3.5 Dilute with water to about 100mL, add 0.1g ascorbic acid and 2 drops of xylenol orange indicator, and titrate with Na2EDTA standard titration solution until the solution changes from orange-red to bright yellow, which is the end point. 6 Expression of analysis results
Calculate the percentage of lead according to formula (2):
Pb(%) = c(V, - V) × 0. 207 2mo
Wherein: c--actual concentration of Na,EDTA standard titration solution, mol/L; Va
the volume of Na2EDTA standard titration solution consumed by the titration test solution during determination, mL; V. The volume of Na,EDTA standard titration solution consumed by the titration blank test bath during determination, mL; (2)
0.2072--the mass of lead equivalent to 1.00mL Na,EDTA standard titration solution [c(Na?EDTA)=1.00mol/LJ g/mol; 39
-the mass of the sample·g.
The result is expressed to two decimal places.
7 Allowable difference
GB/T3884.7-2000
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 1. Table 1
Lead content
5.00~8.00
>8.00~10.00
>10.00~13.00
Allowable difference
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