GB/T 20975.27-2018Methods for chemical analysis of aluminium and aluminium alloys—Part 27: Determination of cerium,lanthanum,scandium—Inductively coupled plasma atomic emission spectrometry method (English PDF)

Foreword

GB/T 20975 "Methods for chemical analysis of aluminium and aluminium alloys" is divided into 31 parts.

- Part 1. Determination of mercury content;

- Part 2. Determination of arsenic content;

- Part 3. Determination of copper content;

- Part 4. Determination of iron content - Orthopenanthroline photometric method;

- Part 5. Determination of silicon content;

- Part 6. Determination of cadmium content - Flame atomic absorption spectrometric method;

- Part 7. Determination of manganese content - Potassium periodate spectrophotometric method;

- Part 8. Determination of zinc content;

- Part 9. Determination of lithium content - Flame atomic absorption spectrometric method;

- Part 10. Determination of tin content;

- Part 11. Determination of lead content;

- Part 12. Determination of titanium content;

- Part 13. Determination of vanadium content - N-benzoyl- Nphenylhydroxylamine spectrophotometric method;

- Part 14. Determination of nickel content;

- Part 15. Determination of boron content;

- Part 16. Determination of magnesium content;

- Part 17. Determination of strontium content - Flame atomic absorption spectrometric method;

- Part 18. Determination of chromium content;

1 Scope

This Part of GB/T 20975 specifies the method for determination of cerium, lanthanum, scandium content in aluminium and aluminium alloys.

This Part is applicable to the determination of cerium, lanthanum, and scandium content in aluminium and aluminium alloys. The aluminium in aluminium and aluminium alloys interferes with the determination of cerium, lanthanum, and scandium. The same amount of aluminium is added to the working curve to eliminate the interference. Cerium, lanthanum, and scandium do not interfere with each other, and other coexisting elements do not interfere with the determination. Measurement range. cerium. 0.005%~0.90%; lanthanum. 0.005%~0.50%; scandium. 0.0002%~0.50%.

2 Method principle

After the sample is dissolved, in dilute hydrochloric acid medium, using inductively coupled plasma atomic emission spectrometer (ICP-AES), the content of cerium, lanthanum, and scandium elements is determined. By matrix matching method, the influence of the matrix on the measurement results is corrected.

3 Reagents and materials

Unless otherwise stated, in the analysis, only Grade 2 water is used.

3.1 Hydrogen peroxide (rho=1.10 g/mL).

3.2 Hydrochloric acid (rho=1.19 g/mL), analytically pure.

3.3 Nitric acid (rho=1.42 g/mL), analytically pure.

3.4 Argon ( >99.99%).

3.5 Hydrochloric acid (1+1).

3.6 Sodium hydroxide (200 g/L).

3.7 Aluminium [w(Al)>=99.99%], before use, dip-rinse with a small amount of acid; then WASH off the acid with water, RINSE 2~3 times with absolute ethyl alcohol, and air dry.

3.8 Aluminium matrix solution (20 mg/mL). WEIGH 10.00 g of aluminium (3.7) into a 500 mL beaker; COVER the watch glass; and ADD a total of 300 mL of hydrochloric acid (3.5) in portions. After the violent reaction is stopped, ADD a few drops of hydrogen peroxide (3.1); slowly HEAT until completely dissolved; then BOIL for a few minutes, COOL; and TRANSFER the solution to a 500 mL volumetric flask; USE water to dilute to volume, and MIX well.

3.9 Standard stock solution of cerium (1 mg/mL). WEIGH 0.3071 g of cerium oxide [w(CeO2)>=99.99%, pre-burned at 1000 °C for 1 h, and cooled in a desiccator] in a 100 mL beaker; ADD 15 mL of nitric acid (3.3). PLACE for a while and HEAT to boil; then ADD 1 mL of hydrogen peroxide (3.1); HEAT at low temperature for 4 times~5 times until complete dissolution; HEAT to boil, and COOL. TRANSFER to a 250 mL volumetric flask; USE water to dilute to volume, and MIX well.

3.10 Standard stock solution of lanthanum (1 mg/mL). WEIGH 0.2932 g of lanthanum trioxide [w(La2O3)>=99.99%, pre-burned at 1000 °C for 1 h, and cooled in a desiccator] in a 100 mL beaker; ADD 50 mL of hydrochloric acid (3.5); HEAT until complete dissolution, and COOL. TRANSFER to a 250 mL volumetric flask; USE water to dilute to volume, and MIX well.

3.11 Standard stock solution of scandium (1 mg/mL). WEIGH 0.3835 g of scandium oxide [w(Sc2O3)>=99.99%, pre-burned at 800 °C for 1 h, and cooled in a desiccator] into a 100 mL beaker; ADD 25 mL of nitric acid (3.3); dropwise ADD hydrogen peroxide (3.1) until completely dissolved. Then BOIL for a few minutes, COOL; and TRANSFER to a 250 mL volumetric flask; ADD 25 mL of nitric acid (3.3); USE water to dilute to volume, and MIX well.

3.12 Cerium standard solution. PIPETTE 10.00 mL of standard stock solution of cerium (3.9) into a 100 mL volumetric flask; USE water to dilute to volume, and MIX well, to obtain cerium standard solution A (100 µg/mL). By stepwise dilution in the same manner, cerium standard solution B (10 µg/mL) can be obtained.

3.13 Lanthanum standard solution. PIPETTE 10.00 mL of standard stock solution of lanthanum (3.10) into a 100 mL volumetric flask; USE water to dilute to volume, and MIX well, to obtain lanthanum standard solution A (100 µg/mL). […]

6 Analytical procedures