Lagoon ash

Many trace elements are present in coal ashes at concentration levels far in excess of average crustal values. Although new uses are being found for fly ashes, there remains an excess production that ends in lagoons, ash mounds and landfill sites. In the ashes produced in coal-fired power plants trace elements are present in minerals such as quartz, mullite and magnetite, but their overall contribution to the bulk is minimal. The trace elements present in the glass are quantitatively more important, but for the more volatile elements it is surface association that is particularly important, because this is the major location in the ash for some elements and they are potentially leachable. 

Singh and Kolay [32] have investigated the process simulation of ash-water interaction and its influence on various geotechnical properties (viz., compaction, consolidation, hydraulic conductivity and shear strength) of lagoon ash as a fill material for its bulk utilization. They have demonstrated that the activation of ash... 

Kolay, P.K., Singh, D.N. Characterization of alkali activated lagoon ash and its application for heavy metal retention. Fuel 8, 483-489 (2002)... 

Keywords Fly ash Hopper ash Lagoon ash Alkali activation Hydrothermal Fusion Grinding Residues Supernatant Characteristics ZeoUtization... 

As well, RFA was collected from lagoon of the thermal power plant. To differentiate the original hopper ash (OHA) and lagoon ash (OLA) from their residues obtained after alkali activation (viz., activated hopper ash, AHA, and activated lagoon ash, ALA) the samples have been designated as listed in Table 5.2. 

Though, in general, G values for the ALA and AHA samples are seen to increase with an increase in the molarity of the NaOH (M < 2.0), randomness in the value of G for the AHA with time, T is noticeable. Incidentally, the residues AHA7 (i.e., the hopper ash treated with 1.0 M NaOH solution for 36 h) and ALA6 (i.e., the lagoon ash treated with 1.0 M NaOH solution for 24 h), exhibit very high G values (2.73 and 2.53, respectively). The increase in G value can be attributed to the... 

In contrast, Table 5.37 also exhibits an increase in Si02 in some of the residues (i.e., ALA2 to ALA6) of the hopper ash, as compared to the lagoon ash. Also, AI2O3 has been noticed to be on the higher side, as compared to the OLA, in these samples except for ALAI. 

Kolay, P.K., Singh, DJ9. Effect of zeolitization on physic-chemico-mineralogical and geotechnical puptaties of the lagoon ash. Canad. Geotech. J. 38(5), 1105-1112 (2001)... 

Chapter 6 Major Findings of the Three-Step Activation Technique This chapter deals with the inferences derived from the novel method three step activation of the hopper ash, which has been ascertained to be the superior ash over the lagoon ash, as described in Chapter-5, by following hydrothermal activation method. Furthermore, this chapter also showcases the outcome of the three-step activation of the fly ash by fusion method to synthesize high grade zeolite-X. 

---