Reduction of metal oxides by carbon in graphite furnaces . Part 1. Temporal oscillations of atomic absorption in the process of slow evaporation of Al, Bi, Cr, In, Mg, Mn, Pb, Sb, Sn and Te oxides

Abstract

Temporal oscillations in the kinetics of carbothermal reduction of oxides of 10 elements (Al, Bi, Cr, In, Mg, Mn, Pb, Sb, Sn and Te) have been observed by electrothermal atomic absorption spectrometry. Microgram amounts of the elements, as their nitrates, were evaporated with slow heating of the graphite tube. With the exception of Al, Cr and Mn, these oscillations were observed for the first time. Some of the features of this phenomenon are described, including the effects of sample mass, acidity of the solution, nature of the graphite substrate, the influence of the presence of Sr and the type of sheathing gas (He and Ar) on the characteristics of Al spikes. Similar results were obtained in two different laboratories.