Alkali-Activated Binders Using Bottom Ash from Waste-to-Energy Plants and Aluminium Recycling Waste

Abstract

Alkali-activated binders (AABs) stand out as a promising alternative to replace ordinary Portland cement (OPC) due to the possibility of using by-products and wastes in their manufacturing. This paper assessed the potential of weathered bottom ash (WBA) from waste-to-energy plants and PAVAL® (PV), a secondary aluminium recycling process by-product, as precursors of AABs. WBA and PV were mixed at weight ratios of 98/2, 95/5, and 90/10. A mixture of waterglass (WG) and NaOH at different concentrations (4 and 6 M) was used as the alkaline activator solution. The effects of increasing NaOH concentration and PV content were evaluated. Alkali-activated WBA/PV (AA-WBA/PV) binders were obtained. Selective chemical extractions and physicochemical characterization revealed the formation of C-S-H, C-A-S-H, and (N,C)-A-S-H gels. Increasing the NaOH concentration and PV content increased porosity and reduced compressive strength (25.63 to 12.07 MPa). The leaching potential of As and Sb from AA-WBA/PV exceeded the threshold for acceptance in landfills for non-hazardous waste.

Sustainable magnesium phosphate micromortars formulated with PAVAL® alumina by-product as micro-aggregate

“…It is expected than more of 1 Mt per year of this kind of by-product are generated in Europe. It is mainly composed of aluminium-rich oxide and hydroxide phases [46,47].…”

“…Recent studies have shown the potential applications of PV in the cement, ceramic, refractory, and building industries [44][45][46]. PV is also used as a precursor source in alkali activation technology because of its high reactive aluminium content [45][46][47]. In this sense, its commercialisation is subject to its chloride content, which cannot be higher than 2%, otherwise, it could only dispose of in a landfill [48].…”

Opportunities and Barriers for Valorizing Waste Incineration Bottom Ash: Iberian Countries as a Case Study

“…The study showed that the valorization of steel and aluminum recovered from IBA enables great energy savings in the steel and aluminum industries, which are energy-intensive sectors. Moreover, the utilization of IBA to produce cement reduced the consumption of natural resources [90,119,120]. Silva et al [11] provided a literature review regarding the environmental performance of the utilization of IBA in construction-related products.…”

Effect of Temperature and Humidity on the Synthesis of Alkali-Activated Binders Based on Bottom Ash from Municipal Waste Incineration

“…Therefore, the scientific community continues to study potential applications for the valorization of IBA, to increase its value-added potential. Some of these potential applications focus on the use of IBA as a precursor in alkali-activation technology [17][18][19][20][21][22].…”