A study on physico-chemical properties and uses of coal ash of Barapukuria Coal Fired Thermal Power Plant, Dinajpur, for environmental sustainability

The Barapukuria 2 x 125 MW Coal Fired Thermal Power Plant generates significant quantities of solid by-products which are conventionally known as fly ash. These quantities are about 0.08 million metric tons per year which is currently disposing into two designated ash ponds as a waste material. Nowadays, this ash disposal process with its safe management becomes environmental important issues and major challenges to the industry, environmentalists, scientists and so on. As a consequence, this study principally deals with the assessment of different properties and uses of coal ash for safe environment around the plant area. Thus, the prime objectives of this research are to evaluate the physical, chemical and engineering properties of coal ash for its classification, suitable options of utilizations and safe environment under direct field investigation and laboratory analysis. The results of various analysis implied that physically the color of ash is light gray but varies from gray to dark gray, where the sizes of the particles are in the ranges from <0.075 to 0.16 mm in diameter; accordingly, this ash can be classified as fine sand/silt to clay. The analyzed major and minor chemical properties of coal ash indicate good quality ash. In addition, the major compositions suggest the similar quality while the concentration of SiO2 (50.61 %), Al2O3 (38.55 %) and Fe2O3 (3.68 %) are about 90 %. The intensity level of major and minor components of this ash is SiO2 > Al2O3 > TiO2 > Fe2O3 > CaO > P2O5 > MgO > K2O > SO3 > Mn3O4 > Na2O and Mn > Zn > As > Cu > Cr > Pb > Co > Cd, respectively. In the case of engineering properties, grain size, hydraulic conductivity, consistency, compaction, compressive strength and shear strength aspects are presented. The results replicate that effect of addition of coal ash with sand and cement can improve the quality of mixtures specifically increasing the consistency, compressive strength, shear strength and bearing capacity, whereas reducing the hydraulic conductivity of concrete or soil. At the end, a concise discussion has been drawn on the prospective utilizations and management of this ash for present and future environmental sustainability around the area.