Abstract
Rare earth elements are characterized by the high risk of their shortage resulting from limited resources.
From this reason REE constitute a group of elements of special importance for the European Union.
The aim of this study was to evaluate ashes from the burning of coal in fluidized bed boilers as an
potential source of REY . Twelve samples of fly ash and bottom ash taken from power plants in Poland
were analyzed. Tests have shown that despite some differences in chemical composition, the fly ash and
bottom ash from fluidized beds could be classified as the calsialic, low acid type. It was found that fly ashes
contained more REY than bottom ashes. Among REY , the light elements (LREY ) had the highest share in
the total REY content in both fly ashes and bottom ashes. Heavy elements (HREY ) had the lowest content.
The normalized curves plotted for fly ash samples within almost all of their entire range were
positioned above the reference level and these curves were of the L-M or H-M type. The content of the
individual REY in these samples was even twice as high as in UCC . The normalized curves plotted
for bottom ash samples were classified as of L, L-M or H type. They were positioned on the reference
level or above it. The content of the individual REY in these samples was the same or up to about
4 times lower than in UCC. It was found that the content of critical elements and of excessive elements in fly ash and bottom
ash differs, which has an effect on the value of the outlook coefficient Coutl, and which is always
higher in the case of fly ash than in the case of bottom ash. Nevertheless, the computed values of the
outlook coefficient Coutl allow both fly ash and bottom ash from fluidized beds to be regarded as promising
REY raw materials.
Go to article