Methods for Chemical Analysis of Lithium Carbonate, Lithium Hydroxide Monohydrate and Lithium Chloride - Part 9: Determination of Sulfate Content - Barium Sulfate Nephelometry Method
1 Scope
This part of GB/T 11064 specifies the methods for determining the sulfate content in lithium carbonate, lithium hydroxide monohydrate and lithium chloride.
This part is applicable to the determination of sulfate content in lithium carbonate, lithium hydroxide monohydrate and lithium chloride within a range of 0.0050%~0.80%.
2 Method summary
In the hydrochloric acid medium, barium ion reacts with sulfate to generate insoluble barium sulfate. With the barium sulfate in suspension for a certain time, measure its absorbance at the wavelength of 420 nm by a spectrophotometer to obtain the sulfate content.
3 Reagents
Unless otherwise specified, analytically-pure reagents and secondary deionized water are used for purpose of this part.
3.1 Hydrochloric acid (1+1): guaranteed reagent.
3.2 Hydrochloric acid (1+3): guaranteed reagent.
3.3 Ammonium hydroxide (1+3): guaranteed reagent.
3.4 Glycerol aqueous solution (1+4);
3.5 Barium chloride solution (200g/L): prepared immediately before use.
3.6 p-nitrophenol indicator solution (1g/L).
3.7 Sulfate standard storage solution: weigh 0.9075g potassium sulfate (guaranteed reagent) which has been baked at 105℃ ~ 110℃ for 2 hours in advance and cooled to room temperature in a dryer, put it in a 250mL beaker, dissolve it in water, transfer it into a 1000mL volumetric flask, dilute to the scale with water, and shake well. This solution contains 500μg of sulfate per 1mL.
3.8 Sulfate standard solution: transfer 20.00mL sulfate standard storage solution (3.7) into a 100mL volumetric flask, dilute to the scale with water, and shake well. This solution contains 100μg sulfate per 1mL.
3.9 Lithium salt matrix solution: weigh 10.00g lithium carbonate w(Li2CO3) ≥ 99.99%] in a 200mL beaker, slowly add hydrochloric acid, and after lithium carbonate is decomposed, transfer the test solution into a 100mL volumetric flask, dilute to the scale with water, and shake well.
Foreword i
1 Scope
2 Method summary
3 Reagents
4 Apparatus
5 Test sample
6 Analysis procedures
7 Calculation of analysis results
8 Precision
9 Test report
