E. Ikavalko et al., Optimised method of coal digestion for trace metal determination by atomicabsorption spectroscopy, FRESEN J AN, 363(3), 1999, pp. 314-316
Understanding the transport of trace elements through a coal-fired power pl
ant requires reliable analytical methods for these elements in all the ingo
ing and outgoing mass streams. Coal and different kinds of ashes comprise t
he most abundant mass streams in such a plant. As a continuation of our pre
vious work, we have optimised a digestion method for the AAS determination
of heavy metals in coal samples. It has become evident that complete dissol
ution of metals in coal samples and accurate results in subsequent analysis
can be obtained by means of applying pressurised digestion under microwave
heating. The combination of HNO3 (conc.) and HF (conc.) in the volume rati
o of 50:1 attacked the sample well enough, and good recoveries for all the
metals studied were obtained. Surprisingly good results were obtained also
when HNO3 alone was used as the digestion acid.