GB/T 23514-2020Methods for chemical analysis of nuclear-grade Ag-In-Cd alloys (English PDF)

2.1 Principle

The sample is dissolved with nitric acid. First use the potentiometric titration method to determine the silver content, use a composite silver electrode, and titrate to the potential with a sodium chloride standard solution End point; adjust the pH of the solution to 2.5, use PAN as an indicator, and titrate the indium with Na2EDTA standard solution; adjust the pH of the solution to 6.0, Continue to titrate cadmium with Na2EDTA standard solution.

2.2 Reagents

Unless otherwise specified, only reagents and laboratory secondary water confirmed to be analytically pure are used in the analysis.

2.2.1 Electrolytic silver (wAg>=99.99%).

2.2.2 Metal indium (wIn>=99.99%).

2.2.3 Metal cadmium (wCd>=99.99%).

2.2.4 Ammonia (rho0.90g/mL).

2.2.5 Glacial acetic acid (rho1.049g/mL).

2.2.6 Nitric acid (rho1.42g/mL).

2.2.7 Nitric acid (1 1).

2.2.8 Sodium hydroxide solution (200g/L).

2.2.9 Acetic acid-sodium acetate solution. Weigh 20g sodium acetate and dissolve in water, add 46.2mL glacial acetic acid (2.2.5), and dilute with water to 500mL, mix well.

2.2.10 PAN indicator. Weigh 0.1g PAN indicator dissolved in 100mL methanol, and mix.

2.2.11 Sodium chloride standard titration solution (c approx. 0.050mol/L). Weigh 2.92g sodium chloride (pre-burned at 560°C for 4h, then put it in a desiccator Cool to room temperature) in a 500mL beaker, add 300mL water to dissolve, transfer to a 1000mL volumetric flask, dilute with water to the mark, and mix.

2.2.12 Disodium ethylenediaminetetraacetic acid (Na2EDTA) standard titration solution (c approx. 0.010mol/L). Weigh 3.72g Na2EDTA and place In a 500mL beaker, add 300mL of water to dissolve, transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix.

2.2.13 Silver indium cadmium (AgInCd80-15-5) standard mixed solution. accurately weigh the metal that has been cleaned with organic reagents and dried in a desiccator Electrolytic silver (2.2.1) 8.0000g, metallic indium (2.2.2) 1.5000g and metallic cadmium (2.2.3) 0.5000g, put them together in a 150mL beaker, Add 50mL nitric acid (2.2.7), heat at low temperature to dissolve the sample completely, remove the nitrogen oxides, and transfer it into a 100mL brown volumetric flask. Dilute to the mark with water and mix well.

2.2.14 Calibration of the concentration of sodium chloride and Na2EDTA standard titration solution. pipette 10.00mL silver indium cadmium standard mixed solution (2.2.13) Place in a 100mL volumetric flask, dilute to the mark with water, and mix well. Pipette 4 parts of the above solution each 10.00mL into four 100mL In a beaker, dilute with water to about 40mL. The following shall be carried out according to 2.5.3.3~2.5.3.5.