DETERMINAÇÃO DE POTÁSSIO EM ROCHAS SILICÁTICAS POR ESPECTROMETRIA DE EMISSÃO ATÔMICA COM CHAMA APÓS DISSOLUÇÃO ASSISTIDA POR ULTRASSOM

• Main Author: Baldez,Daiane L.
• Publication Date: 2018
• Other Authors: Avila,Liziane O., Torres,Daiane P., Martinazzo,Rosane, Silveira,Carlos A. P., Vieira,Mariana A.
• Format: Article
• Language: por
• Source: Química Nova (Online)
• Download full: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422018001001095
• topic: potassium; silicate rocks; ultrasound dissolution; F AES

This work presents the development of an analytical method for sample preparation aiming at the K determination in silicate rocks (basalt, monzogranite and shale fines) following ultrasound dissolution and analysis by F AES. Sample preparation method was optimized by using fractional factorial designs. The following optimal conditions were obtained for each silicate rock: 0.1 g of sample mass for any of the three samples, and volumes of HNO3, HCl and HF, respectively, of 2.5, 0.8 and 2.5 mL for basalt; 3.5, 0.8 and 2.5 mL for monzogranite, and 2.5, 1.0 and 2.0 mL for shale fines. Sample dissolution was achieved by using the ultrasound bath at room temperature (25 °C) for 1 hour. The accuracy was evaluated through the analysis of two certified reference materials, for which there was no statistical difference between the certified and the found K concentration values (95% confidence level). The K concentrations determined were: 1.45 ± 0.01 for basalt; 4.19 ± 0.03 for monzogranite and 1.60 ± 0.02 for shale fines. The developed method presented accurate and reliable results for K amounts in silicate rocks and is simple and safe, which are important features for the implementation of a methodology as a routine analysis.