ASTM E508 – 13 Calcium and Magnesium determination in Iron Ores by Flame Atomic Absorption Spectrometry

Scope:

This test technique is designed to serve as a check for impurity content conformity with compositional criteria. It is assumed that the work would be done in a fully equipped laboratory with suitable waste disposal processes in place.

Procedure:

With the addition of a little quantity of HNO₃, the sample is dissolved in HCl. Any insoluble residue is filtered, processed for calcium and magnesium recovery, and reintroduced to the main solution after evaporation and dehydration. The solution is aspirated into the atomic absorption spectrometer’s flame. A nitrous oxide-acetylene burner is used for calcium, whereas an air-acetylene burner is chosen for magnesium. Atomic absorption spectrometry was used to measure the absorbed energy at the resonance line of the spectrum of calcium or magnesium and compared it to the calibration solutions of the two elements. 

Specimen size:

Pulverized the analytical sample until it passed through a 150-m sieve.

Data:

Calculated the calcium and magnesium mass fractions (percentages) as follows:
Calcium or magnesium, % = (A × 200)/ (B × 10 000)
Where:
A = calcium or magnesium per mL, μg
B = sample represented in the 200-mL volume of the final test solution, g