A straightforward method for determination of Al and Na in aluminosilicates using ICP OES

Abstract

The improvements on aluminosilicates dissolution through microwave-assisted acid decomposition procedures for Na and Al quantification by inductively coupled plasma optical emission spectrometry (ICP OES) are reported here. Complete dissolution of the samples is achieved employing 4 mL of HNO3 and 3-4 mL of HF thus reducing the total amount of these reactants in comparison with procedures found in the literature. Additionally, the type of crucibles used in the calcination for sample preparation step is also evaluated. Na and Al concentrations are in agreement with the expected values on the samples. Estimated silicon amount is achieved by difference of sodium and aluminum, and then Si/Al molar ratios were calculated for samples calcined in both porcelain (Si/Al is in the range 22-42) and platinum (Si/Al is in the range 27-40) crucibles, showing no difference between these procedures.