Synthetic recrystalization matrix for converting coal ash into value added product

• Main Author: Ong, Khiaw Chong.
• Other Authors: Sun Delai, Darren
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Environmental engineering::Waste management
• Online Access: http://hdl.handle.net/10356/15963
• Institution: Nanyang Technological University

Coal ash has been recognized as a hazardous industrial waste due to its high concentration of toxic heavy metals. It is been produced in large quantities by burning of coal in thermal power stations for electrical purpose. Increasing massive amount of coal ash is forecasted, large amount of land is needed to be used for coal ash disposal sites. Moreover, the toxic contaminants will leach out to the surrounding areas causing environmental impact. Human health is greatly endangered as exposure to coal combustion waste has a ninety-nine times higher chance of having cancer than smoking a packet of cigarette each day. Eventually, coal ash will lead to both financial and environmental burdens. Utilization of coal ash in producing glass ceramic is a sustainable solution to the problems. While coal ash is being recycled for glass ceramic, there is great significant value addition as glass ceramic shows good mechanical properties and chemical resistance which is good for industrial usage. The hazardous high concentrations of heavy metals are also being immobilized chemical and physical in the glass ceramic. Moreover, different microstructure and properties of glass ceramic can be produced based on the composition of coal ash used. Experimental work has been carried out using coal ash to produce glass ceramic. Other raw materials used include sodium hydroxide, aluminium nitrate and waste glass. It is realized that all raw materials must be readily prepared in powder form and evenly mixed for good reaction and possible glass ceramic production. Produced glass ceramic shows attractive appearance and good heavy metal immobilization characteristic. It also shows great potential to stabilize other hazardous industrial wastes in its glass ceramic structure both chemically and physically. However, no crystalline phase is detected which means improvement must made for the controlled heat treatment so nucleation and crystallization are possible.