Browsing by Author "Shivadhahini, S"

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item: Conference-Abstract
Experimental investigation and performance optimisation of washing cycles for pre-processing of coal fly ash
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Brinthan, K; Shivadhahini, S; Senadheera, UAG; Fernando, WAM; Jayawardena, CL; Jayasundara, DRT; Wickrama, MADMG; Jayawardena, CL
Coal Fly Ash (CFA), a by-product of thermal power plant combustion, has a profound focus among researchers due to its pozzolanic properties, porosity, wide chemical composition, and thermal stability. While being suitable for many applications (e.g., pozzolanic material, soil stabiliser, and structural fill), CFA is also a potential precursor for synthesising zeolites, broadly used in wastewater treatment. However, pre-processing is crucial due to the heterogeneous nature of CFA. This work focused on pre-processing CFA prior to wastewater treatment through continuous washing cycles at various operating temperatures. To this end, we studied the pH and conductivity of the solution after washing over multiple cycles, Sauter mean diameter, and the mineralogy of the settled CFA. The gathered results were analysed and optimised through response surface methodology. This was done to find the best combination of the number of washing cycles and temperature to remove soluble ions and increase the surface area of CFA particles. The analytical outcome revealed that five washing cycles at 70°C were adequate, with minimal soluble ions and maximum surface area. Evidently, these findings demonstrated significant improvements in the physical and chemical properties of CFA as a precursor for zeolite synthesis. Therefore, we recommend further studies on this front to extend the effective usage of CFA for the synthesis of commercial zeolites to be used for wastewater treatment.
item: Conference-Full-text
A study of underground and surface mining methods in Sri Lanka and its suitability assessment
(Department of Earth Resources Engineering, University of Moratuwa, 2021-12) Thanujan, T; Brinthan, K; Shivadhahini, S; Subasinghe, MAIIJ; Vettinathan, S; Dharmaratne, PGR; Hemalal, PVA; Chaminda, SP; Jayawardena, CL; Dissanayake, DMDOK; Jayawardena, CL
The demand for minerals is rapidly increasing with industrialization, urbanization, and population growth. Sri Lanka has the potential to penetrate the world market with its endowed rich base of minerals despite its small land area. However, selecting a suitable mining method and its optimum utilization have significant roles in the growth of the local mineral mining industry. The lack of systematic approaches in mining methods is suboptimal for the economic growth of Sri Lanka, which demands immediate investigation and reassessment of contemporary mining practices. Thus, this study aims to critique the major mining practices and evaluate their suitability through characteristics and numerical analysis. This investigation was performed for underground mining methods: cut-and-fill stoping and open-stoping; surface mining methods: open-pit, and open-cast placer mining with reference to Bogala, Kahatagaha, Aruwakkalu, and Pulmoddai, respectively. A detailed study complying with the principles of the grounded theory was conducted through a multimethod approach followed by a thematic and content analysis along with the deductive approach. Moreover, the suitability of these methods was evaluated employing the University of British Columbia method through a numerical approach. This study reveals that the selections of mining methods are appropriate for all four mines, and mining practices are modernized and traditional, complying with site-specific requirements.