Environmental Engineering Reference
In-Depth Information
F(1) - exchangeable fraction,
F(2) - carbonate fraction,
F(3) - oxide fraction,
F(4) - organic or sulfide fraction,
F(5) - residue
Figure 2. Distribution of chemical fraction of Cd in coal fly ash for various procedures
of sequential extraction.
Cd (exchangeable) < Cd (carbonate) < Cd (oxide) < Cd (organic, sulfide)
For remaining procedures: Rudd, BCR, Sposito, Psenner and Gatehouse
no regular dependences of Cd amount in individual chemical fraction was
obtained (Figure 2).
Results indicate on the possibility of transfer of Cd from coal fly ash to
coal fly ash environment in conditions of neutral condition or weak acid
condition (pH = 5). Obtained order of Cd fraction in coal fly ash can change in
time depending on physicochemical parameters of coal fly ash, special pH and
temperature, that lead to change of solubility of Cd compounds and their
tendency to extract from coal fly ash to coal fly ash environment.
Search WWH ::
Custom Search