GB/T 15072.10-1994 Chemical analysis methods for precious metals and their alloys Determination of nickel content in gold alloys GB/T15072.10-1994 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis methods for precious metals and their alloys
Determination of nickel content in gold alloys
Gold alloysDetermination of nickel contentSubject content and scope of application
This standard specifies the method for determining the nickel content in gold alloys. GB/T 15072. 10 -- 94
This standard is applicable to the determination of nickel in AuNi9, AuNiCu7.5-1.5, AuNiIn9-8, AuNiFeZr5-1.5-0.3 and AuNiFeZr9-2-0.3 alloys. Determination range: 5%~~10%. 2 References to [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 3 Method summary
The sample is dissolved in mixed acid, gold is separated by sulfurous acid reduction, nickel is precipitated by dimethylethylenediamine, and dimethylethylenedinickel is dissolved by hydrochloric acid. Add excess Na, EDTA, and dimethylphenol orange as an indicator, and back titrate with zinc chloride standard titration solution to determine the amount of nickel. 4 Reagents
4. 1 Sulfurous acid (pl. 03 g/mL).
4.2 Ammonia water (p0. 90 g/ml.).
4.3 Ammonia water (1+1).
4.4 Ammonia water (1+99).
4.5 Hydrochloric acid (1+1).
4.6 Mixed acid: 3 units of hydrochloric acid (p1.19 g/mL) and 1 unit of nitric acid (pl.42 g/ml.), prepare it when needed. 4.7 Citric acid solution (300 g/L).
4.8 Tartaric acid solution (500 g/L).
4.9 Ascorbic acid solution (50 g/L), prepare it when needed. 4.10 Sodium chloride solution (100 g/L).
Ammonium chloride solution (250 g/L).
Dimethylethylenediethanol solution (15 g/L). 4.13 Hexamethylenetetramine solution (400 g/L). 4.14 Thiourea solution (100 g/L).
1,10-Phenanthroline ethanol solution (2 g/L). 4.15
4.16 Nickel standard solution: Weigh 1.0000g of metallic nickel, place in a 250mL beaker, add 10mL of hydrochloric acid (p1.19g/mL), heat at low temperature to dissolve, evaporate to 2-3mL, add 30mL of hydrochloric acid (p1.19g/mL), transfer to a 1000ml volumetric flask, dilute to scale with water, mix evenly, this solution contains 1mg nickel per mL.
GB/T 15072.10—94
4.17 Disodium ethylenediaminetetraacetic acid (NazEDTA·2H,O) solution (0.02mol/L). 4.18 Zinc chloride standard titration solution [c(ZnCl2) 0.008mol/L]. 4.18.1 Preparation: Weigh 1.046g of metallic zinc into a 250ml beaker, add 10mL of hydrochloric acid to dissolve, evaporate to 2~~3mL. Add 5ml of hydrochloric acid (p1.19g/mL), transfer to a 2000mL volumetric flask, dilute to scale with water, and mix well. 4.18.2 Calibration: Calibration is carried out in parallel with the determination of the sample. 4.18.2.1 Titrate Na, EDTA solution according to (6.2.3). 4.18.2.2 Transfer 10.00mg of nickel standard solution, place it in a 250mL beaker, add 160mL of water, 15mL of ammonium chloride solution, and stir well. The following is carried out according to (6.2.2.2) and (6.2.3). Titrate three times in parallel. The extreme value of the volume of zinc chloride standard titration solution consumed in calibration should not exceed 0.10mL, and the average value is taken. wwW.bzxz.Net
Carry out a blank test together with the calibration.
Calculate the actual concentration of zinc chloride standard titration solution according to formula (1): m
c = (V, - V.) × 0. 058 69
Wherein; c-actual concentration of zinc chloride standard titration solution, mol/L.; mi-mass of nickel removed from nickel standard solution, g; V. Volume of zinc fluoride standard titration solution consumed by titrating NazEDTA solution, ml.; V,-volume of zinc chloride standard titration solution consumed by titrating excess Na2EDTA in nickel standard solution, ml.; (1)
0.05869-mass of nickel in grams equivalent to 1.00mL zinc chloride standard titration solution [c(ZnCl2)=1.000mol/1.1. Xylenol orange solution (2g/L).
5 Sample
The sample is processed into debris, and finally degreased with acetone, washed, dried and mixed. 6 Analysis steps
6.1 Sample
Weigh 0.1g of sample, accurate to 0.0001g. Perform two independent measurements and take the average value. 6.2 Measurement
6.2.1 Dissolution
Put the sample in a 250ml beaker, add 5ml of mixed acid, cover surface III, and heat at low temperature until completely dissolved. Remove, rinse surface IIIL and the wall of the cup with water, add 0.5mL of sodium chloride solution, and evaporate at low temperature until almost dry. Add 2mL of hydrochloric acid and evaporate to wet salt, repeat three times. Add 2 drops of hydrochloric acid, 100mL of water, boil, add 10ml of sulfurous acid, boil for 30min, and cool to room temperature. 6.2.2 Precipitate nickel
6.2.2.1 Add 70 mL of water and 15 mL of ammonium chloride solution to the gold-nickel and gold-nickel-copper test solutions and stir to make a homogenous mixture; add 70 mL of water, 1 mL of tartaric acid solution and 15 mL of ammonium chloride solution to the gold-nickel-steel test solution and stir to make a homogenous mixture; add 70 mL of water, 5 mL of citric acid solution and 15 mL of ammonium chloride solution to the gold-nickel-iron-zirconium test solution and stir to make a homogenous mixture.
6.2.2.2 Add 6 mL of dimethylethylenediamine solution, stir, and drop ammonia water (4.2) until a red precipitate appears. Continue to drop ammonia water (4.2) until pH 8 and let stand for 60 min. Filter with medium-speed quantitative filter paper, and wash the beaker and precipitate five times with ammonia water (4.4). Add 16 mL of hydrochloric acid (add 2 mL dropwise each time) to dissolve the precipitate in the original beaker, wash the filter paper five times with water, and add water to 80 mL. 6.2.3 Titration
Add 15.00mL Na2EDTA solution, 7mL hexamethylenetetramine solution, 5 drops of xylenol orange solution, adjust to 99
GB/T 15072.10-94
pH 5.8 with ammonia water (4.3) (if the sample contains copper, add 5mL thiourea solution, 2mL ascorbic acid solution, 2 drops of 1.10-phenanthroline solution, let stand for 10 minutes), and titrate with zinc chloride standard titration solution until the solution changes from yellow to purple-red as the end point. 7 Expression of analytical results
Calculate the percentage of nickel according to formula (2):
Ni(%) = eX(V.- V2) × 0. 058 69 2×100
Wherein; c—actual concentration of zinc chloride standard titration solution, mol/L, V. ---The volume of zinc chloride standard titration solution consumed by titrating Na2EDTA solution, mLV-the volume of zinc chloride standard titration solution consumed by the excess Na2EDTA in the titration test solution, mLm-the mass of the sample, g;
0.05869-the mass of nickel in grams equivalent to 1.00mL zinc chloride standard titration solution c(ZnCl2)-1.00mol/LJ. The result should be expressed to two decimal places.
8 Allowable difference
The difference in analysis results between laboratories should not exceed 0.10%. Additional remarks:
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by Kunming Precious Metals Research Institute. This standard was drafted by Kunming Precious Metals Research Institute. The main drafter of this standard is Hong Ying.
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