Phase-mineral and chemical composition of fractions separated from composite fly ashes at the Soma power station, Turkey
✍ Scribed by Stanislav V. Vassilev; Christina G. Vassileva; Ali I. Karayigit; Yilmaz Bulut; Andres Alastuey; Xavier Querol
- Publisher
- Elsevier Science
- Year
- 2005
- Tongue
- English
- Weight
- 950 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0166-5162
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✦ Synopsis
The phase-mineral and chemical composition of six fractions recovered from two fly ashes (FAs) produced in the Soma power station (Turkey) was characterized to predict their possible environmental concerns and potential utilization directions. A combination of conventional separation procedures including sieving, hand picking, sink-float and magnetic separations, as well as leaching and evaporation, was used to isolate the following fractions: (1) char concentrates (CCs); (2) light fractions (b1 g cm À3 ) (LFs); (3) water-soluble residues (WRs); (4) magnetic fractions (MFs); (5) nonmagnetic coarse-grained fractions (N63 Am) (NCFs); and (6) nonmagnetic fine-grained fractions (b63 Am) (NFFs). CCs (3.3-3.4%) are composed of char (61-68%) and some inorganic phases, and are highly enriched in UNSNMnNMoNFeNSb. LFs (0.4-0.8%) contain porous cenosphere, spongy, and vesicular char types (21-54%) impregnated by calcite, anhydrite, portlandite, and clay minerals. These fractions show high concentrations of SbNSeNAs. WRs (1.7-2.6%) consist of gypsum, portlandite, Ca oxalate, and calcite (92-98%), and are highly enriched in water-soluble SbNMoNSNCa. The greatest amounts (1-37%) leached from FAs reveal SbNMoNSNCaNSrNSeN(B, Na)NLi. MFs (1.4-2.3%) are concentrated in magnetite, hematite, and Fe-spinel (31-39%), and are highly enriched in MnNFeNCoNCuNNiNZnN(Mo, Yb)N(Lu, Tm, Y)N(Er, Ho, Mg)NSb. NCFs (49-56%) include mostly coarse-grained glass, quartz, calcite, and mullite, and these are the poorest in trace elements fractions. NFFs (39-47%) contain dominantly fine-grained glass, calcite, quartz, char, and mullite, and are slightly enriched in some chalcophile elements. Possible environmental concerns are related mainly to the trace element mobility in WRs, LFs, and CCs, while the potential utilization directions are connected mostly with the composition of MFs, WRs, CCs, LFs, and NFFs.