Methods for chemical analysis of lithium carbonate,lithium hydroxide monohydrate and lithium chloride - Part 5: Determination of calcium content － Flame atomic absorption spectrometric method
1 Scope
This part of GB/T 11064 specifies the methods for determining the calcium content in lithium carbonate, lithium hydroxide monohydrate and lithium chloride.
This part is applicable to the determination of calcium content in lithium carbonate, lithium hydroxide monohydrate and lithium chloride, within the range of 0.0020%~0.35% .
2 Method summary
The test sample of lithium carbonate and lithium hydroxide are decomposed with hydrochloric acid, and test sample of lithium chloride is dissolved with water. In diluted hydrochloric acid medium, determine with air-acetylene flame and standard addition method using lanthanum salt and citric acid as releasing agents at the wavelength of 422.7nm by atomic absorption spectrometer.
3 Reagents
Unless otherwise specified, guaranteed reagents and secondary deionized water are used for purpose of this part.
3.1 Hydrochloric acid (1+1).
3.2 Lanthanum salt solution: weigh 5.864 g lanthanum oxide [w (La2O3) ≥ 99.9%], put it into a 100 mL beaker, add hydrochloric acid dropwise to make it clear (heat it if necessary), transfer it into a 500 mL volumetric flask, dilute it to scale with water, and shake it well. This solution contains 10 mg La/mL.
3.3 Citric acid solution (100 g/L): weigh 50 g citric acid and put it in a 500 mL beaker, add about 500 mL water to dissolve it, and purify it with hydrogen cation exchange resin.
3.4 Calcium standard storage solution: weigh 2.4972 g calcium carbonate [w(CaCO3) ≥ 99.9%], which is baked at 105°C for 2 h in advance and cooled to room temperature in a dryer, and put into a 250 mL beaker. Add 100 mL water, cover it with watch glass, slowly add 10 mL hydrochloric acid (3.1) from the cup mouth, heat it until calcium carbonate is completely dissolved, boil it to remove carbon dioxide, cool it to room temperature, wash the watch glass with water, transfer it into a 1 000 mL volumetric flask, dilute it to the scale with water, and shake it well. This solution contains 1.0 mg calcium per 1 mL.
3.5 Calcium standard solution: take 50.00 mL calcium standard storage solution (3.4), put it in a 500 mL volumetric flask, dilute it to the scale with water, and shake it well. This solution contains 100 μg calcium per 1 mL.
Foreword i
1 Scope
2 Method summary
3 Reagents
4 Apparatus
5 Test sample
6 Analysis procedures
7 Calculation of analysis result
8 Precision
9 Test report
