SN/T 5248-2020Method for determination of gold content in imported gold-loaded resin materials-flame atomic absorption spectrometry (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard was proposed and managed by the General Administration of Customs of the People's Republic of China.

Drafting organizations of this standard. Urumqi Customs of the People's Republic of China, Shanghai Tuomi Testing Technology Service Co., Ltd., Xinjiang Agriculture University College of Chemical Engineering, Beilun Customs of the People's Republic of China, Xinjiang Shuiqingqing Environmental Monitoring Technology Service Co., Ltd., Xinjiang Uyghur Autonomous Region Analysis and Testing Research Institute, Tianjin Customs of the People's Republic of China, Xinjiang University.

1 Scope

This standard specifies the atomic absorption spectrometry method for the determination of gold content in gold-loaded resin materials.

This standard applies to the determination of gold content in gold-loaded resin materials.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 602 Preparation of standard solutions for impurity determination of chemical reagents GB/T 6682 Analytical laboratory water specifications and test methods

3 Method summary

After the sample is roasted to remove sulfur and organic matter, it is dissolved with hydrochloric acid and nitric acid, and the gold, the adsorbed gold chloride complex or the After the gold bromine complex is dissolved and liberated with thiourea, its gold content is measured with a flame atomic absorption spectrometer.

4 Reagents and materials

Unless otherwise specified, only reagents confirmed to be analytically pure are used in the analysis, and the experimental water meets the first-grade water specified in GB/T 6682.

4.1 Hydrochloric acid (rho=1.19 g/mL).

4.2 Nitric acid (rho=1.42 g/mL).

4.3 Thiourea.

4.4 Bromine.

4.5 Dilute hydrochloric acid (1.9).

4.6 Gold standard stock solution (1 000 µg/mL). Prepare according to GB/T 602 method or directly use certified national standard materials.

4.7 Gold standard working solution (100 µg/mL). Pipette 10 mL of gold standard stock solution (4.6) into a 100 mL volumetric flask, and use dilute hydrochloric acid (4.5) Dilute to the mark and mix well.

4.8 Aqua regia. mix 3 parts of hydrochloric acid (4.1) and 1 part of nitric acid (4.2), and prepare when used.

4.9 Aqua regia (1.1). Mix 1 part of aqua regia (4.8) and 1 part of water, and prepare when used.

4.10 Saturated bromine water. Dissolve a certain amount of bromine (4.4) in water, partially dissolve bromine (4.4), and take the supernatant to obtain saturated bromine (4.4).

And bromine water.

4.11 Thiourea solution (10 g/L). Weigh 1 g of thiourea (4.3) and dissolve it in 100 mL of water.

4.12 Sodium hydroxide solution (10 g/L). Weigh 10 g of sodium hydroxide and dissolve it in 1 L of water.

4.13 Plastic foam. polyurethane type or polyether type, cut into blocks of 3 cm×3 cm×1 cm, rinse with water before use, Boil in sodium solution (4.12) for 15 minutes, wash with water until neutral, dry, and set aside.

5 Apparatus and equipment

5.1 Atomic absorption spectrophotometer. equipped with a gold element hollow cathode lamp.

5.2 Analytical balance. Sensitivity is 0.0001 g.

5.3 High-temperature furnace. The temperature can be controlled between 500 °C and 1 000 °C.

5.4 Electric heating plate. can be heated to.200 °C.

5.5 Oscillator.

5.6 Porcelain crucible. 30 mL.

5.7 Colorimetric tube. 25 mL.

5.8 Volumetric flask. 50 mL.

6 Sample

The particle size of the gold-loaded resin material analysis sample should be less than 0.096 mm, and it should be baked at 105 °C ± 5 °C for 2 h, and then cooled to room temperature in a desiccator for later use.

7 Analysis steps

8 Result calculation

Calculate the content of gold in the sample according to formula (1).

omegai-the content of each gold element, in micrograms per gram (µg/g);

cx-the concentration of gold in the sample solution obtained from the working curve, in micrograms per milliliter (µg/mL);

c0-the concentration of gold in the blank solution obtained from the working curve, in micrograms per milliliter (µg/mL);

V-the volume of the sample solution, the unit is milliliters (mL);

m-the mass of the sample, the unit is grams (g);

k - Dilution factor.

Note. The result is the arithmetic average of two parallel determination results, expressed to two decimal places.

9 Precision

Under repeatability conditions, the absolute difference between the two independent determination results is not more than 20% of the arithmetic mean. Under repeatability conditions, two the absolute value of a laboratory measurement result is not more than 30% of the arithmetic mean.

Appendix A

(Informative appendix)