YS/T 273.16-2020Methods for chemical analysis and physical properties test of cryolite - Part 16: Determination of lithium content - Flame atomic absorption spectrometric method (English PDF)

Foreword

YS/T 273 Chemical analysis methods and physical properties of cryolite consists of the

following 17 parts:

--- Part 1: Determination of moisture content by gravimetric method;

--- Part 2: Determination of ignition loss;

--- Part 3: Determination of fluoride content;

--- Part 4: Determination of aluminum by the EDTA volumetric method;

--- Part 5: Determination of sodium by flame atomic absorption spectrometric method;

--- Part 6: Determination of silica content by the molybdenum blue photometric;

--- Part 7: Determination of iron content by orthophenantholine photometric method;

--- Part 8: Determination of sulphate content by barium sulphate gravimetric method;

--- Part 9: Determination of phosphorous pentoxide content – Molybdenum blue

photometric method;

--- Part 10: Determination of alumina content by gravity method;

--- Part 11: Determination of sulphur content by X-ray fluorescence spectrometric method;

--- Part 12: The atomic absorption spectrophotometric method for the determination of

calcium oxide content;

--- Part 13: Preparation and storage of test samples;

--- Part 14: X-ray fluorescence spectrometric method for the determination of elements

content;

--- Part 15: X-ray fluorescence spectrometric method for the determination of elements

content using pressed powder tablets;

--- Part 16: Determination of lithium content – Flame atomic absorption spectrometric

method;

--- Part 17: Determination of elements content – Inductively coupled plasma atomic

emission spectrometric method.

This Part is Part 16 of YS/T 273.

Methods for Chemical Analysis and Physical Properties Test

of Cryolite – Part 16: Determination of Lithium Content –

Flame Atomic Absorption Spectrometric Method

1 Scope

This Part specifies the method for determination of lithium content in cryolite.

This Part applies to the determination of lithium content in cryolite. Measuring range:

0.010%~1.50%.

2 Method Summary

Use perchloric acid to remove all fluorine from the test material; and then dissolve it with

hydrochloric acid and water. The test solution is measured at the wavelength of 670.8 nm of the

atomic absorption spectrometer using an air-acetyl block flame to measure the absorbance of

lithium; and the lithium content is calculated.

3 Reagents

Unless otherwise stated, only reagents and laboratory Class-III water determined to be of

analytically pure are used in the analysis.

4 Apparatus

Atomic absorption spectrometer with lithium hollow cathode lamp.

Under the best working conditions of the instrument, any instrument that can meet the following

indicators can be used:

--- Sensitivity: In a solution consistent with the matrix of the measurement test material

solution; the characteristic concentration of lithium shall be no greater than 0.028µg/mL;

--- Precision: Use the standard solution with highest concentration to measure the

absorbance for the most 10 times; and the standard deviation shall not exceed 1.0% of

the average absorbance.

Use the standard solution with lowest concentration (not the solution with zero

concentration) to measure the absorbance 10 times; and its standard deviation shall not

exceed 0.5% of the average absorbance of the standard solution with highest

concentration;

--- Standard curve linearity: In standard solutions with equal-difference concentration, the

ratio of the absorbance difference on the highest segment to the absorbance difference

on the lowest segment shall be no less than 0.7.

5 Specimen

The specimen is ground and mixed, and passed through a 75µm standard sieve; baked in an

oven at 110°C ± 5°C for 2 h; and cooled to room temperature in a desiccator.

6 Test Procedures