The effect of marble waste in the production of low-temperature porous material from Alkali-activated fly ash

The production of low-cost open-pore ceramic materials from fly ash (FA) and marble waste (MW) was investigated.The effect of MW (5-40 wt.%) onthe open porosity was determined. To reduce the sintering temperature and improve the properties of porous materials, the mixtures were activated with an alkali solution. Samples pressed from FA and FA+MW mixtures were sintered at low temperature (900 °C), but sufficient strength could not be obtained. However, when these mixtureswere subjected to alkali activation, pressed and sintered at 900 °C, sufficient strength and porosity values were reached. The open porosity of the MW neat specimen was 12.70%, but it increased up to 39.91% at 40 wt.% MW, which was the highest ratio used in the literature. The main phase structure was nepheline at 0-20 wt.% MW, but gehlenite became the dominant phase at 40 wt. % MW. The compressive and flexural strength values of 40 wt.% MW added specimen was determined to be 12 and 5.35 MPa, respectively.The open-pore ceramic of high MW ratio, produced by this new alternative route, has the potential for use in water purification membranes for macro filtration purposes.