Application of Fly Ash and Slag Generated by Incineration of Municipal Solid Waste in Concrete

Abstract

As landfill space for the disposal of products of municipal solid waste incineration (MSWI) such as fly ash and slag becomes increasingly scarce, a reduction of disposed material is urgently required. The method of using incineration products in concrete production is explored in this paper through a feasibility study of utilizing fly ash and slag to replace cement and coarse aggregate in appropriate proportions. Results show that C30 concrete optimum replacement rates of fly ash and slag are 30% and 20%, which can meet the minimum strength requirement. The leaching concentrations of Cu, Zn, Pb, Cr, and Cd in MSWI concrete samples are determined to be less than the identification value of solid waste leaching toxicity. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses, MSWI fly ash has certain dispersion. The particle size of MSWI fly ash is determined to be close to that of the coal fly ash, and the surface morphology is irregular. The main components include SiO2, CaCO3, and Ca2SiO4, and they are similar to those present in the coal fly ash. The slag structure is loose as well as irregular, and its main component is SiO2. The SiO2 and Al2O3 in fly ash and slag participate in the hydration reaction of cement and can increase concrete strength. It is thus confirmed that fly ash and slag generated by waste incineration can be used to replace cement and coarse aggregate in appropriate proportions, and it is an effective method to solve the problem of scarcity of solid waste landfill space.

Synthesis and Characterization of Amorphous Iron Oxide Nanoparticles by the Sonochemical Method and Their Application for the Remediation of Heavy Metals from Wastewater

“…Both being volatile in nature, a major amount of Hg and Cd are eliminated from the coal at the time of combustion in the furnace. Moreover, it has been found that smaller the size of fly ash particles higher will be the concentration of heavy metals on their surface i.e., larger fly ash particles will have lesser amount of heavy metals and other elements on their surface than the small-sized fly ash particles [69,70]. In a thermal power plant, there are two types of ashes; bottom ash and fly ash [71].…”

Analysis of the Possibility of Using Slags from the Thermal Treatment of Municipal Waste as Potential Component of Cement—Case Study

“…The first stage of the valorisation process is initial seasoning to dehydrate and stabilise the slag. Then, appropriate size fractions and ferrous and non-ferrous metals are separated using a magnetic and induction separator [ 22 , 23 ]. Figure 3 presents the tested slags in the raw state (a1,b1) and after mechanical treatment (a2,b2).…”

“…The studied MSWI ashes exhibit a high concentration of chlorides and sulfates, which is an unfavourable feature for a potential concrete additive [ 21 , 22 ]. Publication [ 23 ] indicated that the MSWI slag structure is loose and irregular, and its main component is SiO 2 . The SiO 2 and Al 2 O 3 in fly ash and slag participate in the hydration reaction of cement and can increase concrete strength.…”

Recycling of Coal Fly Ash as an Example of an Efficient Circular Economy: A Stakeholder Approach

“…The coal fly ash is used in the concrete production process in China. Zeng has found the optimum substitution level in concert production as ash substitution level to be 30% and the slag substitution level to be 20% [83]. According his research the strength of concrete mixed with certain amount of coal fly ash was not diminished.…”

“…Berndt pointed out that we can spot the benefits of partial cement replacement with recycled coal fly ash. This is not only economically beneficial, but is also a very important factor towards the promotion of sustainable concrete production [83].…”