Composition and Morphology Characteristics of Magnetic Fractions of Coal Fly Ash Wastes Processed in High-Temperature Exposure in Thermal Power Plants

Abstract

Coal-fired power stations are one of the primary sources of power generation in the world. This will produce considerable amounts of fly ash from these power stations each year. To highlight the potential environmental hazards of these materials, this study is carried out to evaluate the characterization of fly ashes produced in thermal power plants in northern Vietnam. Fly ash was firstly fractionated according to size, and the fractions were characterized. Then, each of these fractions was analyzed with regard to their mineralogical features, morphological and physicochemical properties. The analytical results indicate a striking difference in terms of the characteristics of particles. It was found that magnetic fractions are composed of magnetite hematite and, to a lower rate, mullite, and quartz. Chemical analyses indicate that the non-magnetic components mainly consist of quartz and mullite as their primary mineral phases. As the main conclusion of this research, it is found that the magnetic and non-magnetic components differ in terms of shape, carbon content and mineralogical composition. In addition, it was found that magnetic components can be characterized as more spheroidal components compared to non-magnetic ones. This comprehensive characterization not only offers a certain guideline regarding the uses of different ash fractions but it will also provide valuable information on this common combustion process.

Separation of Cenospheres from Lignite Fly Ash Using Acetone–Water Mixture

“…Those precipitates are in various sizes and shapes such as spherical and nonspherical particles, needles, small spheres with whiskers, and corrugated surfaces. Such morphological characteristics of corrugated, rough surfaces, noticeably indicated in fine fractions, are classified as crystallite depositions on the surfaces of magnetic components such as iron oxides, which are mostly found on magnetic spheres [51][52][53][54]. In cenospheres with a high iron content, part of the outer surface contains heterogeneous regions with extended linear inclusions of ferrospinels, while on the inner surface, the pores contain the underlying aluminosilicate phase [31].…”

Influence of Adding Plant Fly Ash on The Geotechnical Properties and Pollution of Sanitary Landfill Soil

“…Figure 13 shows the random and compact dense distribution of nanoparticles in the form of granular aggregations of different sizes with the appearance of other semispherical formations. Others are similar to nanorods, and the growth method of nanoparticles is roughly consistent with [18] to [19,20].…”

A Product Diffusion Model for the Extraction of Cerium and Yttrium from Magnetic Coal Fly Ash Using Citric Acid Solution

“…Meanwhile, magnetite and hematite in magnetic fly ash comes from the conversion of other iron minerals, mainly pyrite, in coal (Kukier et al, 2003). While non-magnetic fly ash usually has irregular shapes, magnetic fly ash is generally spheroidal (Vu et al, 2019). Scanning electron microscope analysis shows that magnetic fly ash from the Tanjung Awar-awar power plant corresponds to this finding since its shape tends to be spherical.…”

“…Scanning electron microscope analysis shows that magnetic fly ash from the Tanjung Awar-awar power plant corresponds to this finding since its shape tends to be spherical. These magnetic particles are formed by transforming and melting mineral matters in coal which condense into spheroidal particles and are followed by the deposition of Fe or Fe oxide from iron carbonate on the particle surface (Vu et al, 2019).…”