Abstract
Alkali-activated materials were prepared from pond ash from the Darkhan city (Mongolia) thermal power station. This ash contains about 60 wt % X-ray amorphous material in addition to quartz, mullite, hematite and magnesioferrite, and presents significant storage problems since it is accumulating in large amounts and is a hazardous waste, containing 90–100 ppm of the heavy metals As, Pb and Cr, and about 800 ppm Sr. Alkali-activated materials synthesized from the as-received pond ash achieved compressive strengths of only 3.25 MPa. Reduction of the particle size by mechanical milling for up to 30 min progressively increases the compressive strength of the resulting alkali-activated geopolymer up to 15.4 MPa. Leaching tests indicate that the combination of milling and alkali treatment does not cause the release of the hazardous heavy metals from the product, making it suitable for construction applications.
Highlights
RESUMEN: Propiedades de geopolímeros preparados a partir de cenizas de estanque
Coal combustion by-products from power stations constitute a significant amount of the total world waste, stated by some authors to be at least 750 million tonnes of fly ash being produced annually [1]
The present paper reports the effect of grinding on the microstructure of Mongolian pond ash and on the improvement of the mechanical properties of alkali activated materials produced from this starting material by grinding for varying periods to reduce its particle size
Summary
RESUMEN: Propiedades de geopolímeros preparados a partir de cenizas de estanque. Se prepararon materiales activados alcalinamente a partir de cenizas de charca de la central térmica de Darkhan (Mongolia). The properties of pond ash generally vary significantly with the coal type, burning conditions, time spent in the slurry pond and particle size separation during wet storage [13]. For this reason, only a few studies have been made of pond ash applications, including the production of geopolymers [14, 15]. Previous research on pond ash utilization has not paid much attention to the change in the physical properties of pond ashes after storage under wet conditions for prolonged periods Under these conditions, the soluble components of the ashes are dissolved, making more porous and of decreased density; upon alkaline production of geopolymers from stored pond ashes, these factors result in the absorption of a large amount of liquid phase, increasing the liquid:solid ratio of the mixture, weakening the mechanical properties of the geopolymers
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
