Use of Municipal Solid Waste Incineration (MSWI) Fly Ash for Manufacturing Ecological and Energy Saving Cements
W. Luhowiak, E. H. Kadri, A. Lefevre, M. P. Petruk, and K. Sobol
Appears on pages(s):
blast furnace slag; clinker; ecological cement; gypsum; limestone; low-energy cement; municipal solid waste incineration fly ash; portland cement; zeolite
Large quantities of municipal solid waste combustion residues are produced during the incineration of municipal wastes. The necessity of utilizing (MSWI) fly ash for manufacturing ecological and energy saving cements was the aim of this investigation. A partial substitution of Portland cement clinker by MSWI fly ash and zeolite which is a common raw material in Ukraine has led to manufacture high-quality blended cements. Three mineral additives were mixed in the clinker. The systems consist of 50 to 800/c clinker, 10 to 30% blast furnace slag (BFS), 10 to 20% zeolite, and 10 to 20% MSWI fly ash, and 5% gypsum added for all systems. The study evaluated compressive strength of pastes made with these binders, along with the effects of binder proportions. The changes in strength were monitored by differential thermal analysis (DTA) and scanning electron microscope (SEM). Three endothermic peaks appear at 150°C, 400°C, 780°C due to the loss of water, modification of morphology, and carbonates decomposition. SEM was used to study the morphology of hydrating binders. Needle shape and fibre crystals of calcium hydrosilicate and tabular hexagonal plates of Ca(OH)2 were noticed. CaCO3, quartz, hydrocarboaluminates, and calcium hydrosulfoaluminates were also present. XRD patterns show that zeolite play an important part. Its presence leads to an activation of the hydration process and an acceleration of pozzolanic reaction between Ca(OH)2 and cement additives. The 5001c clinker, 30% BFS, 10010 MSWI fly ash, 10% zeolite cement system was the optimum quantity of MSWI fly ash which could be re-cycled in the manufacture of ecological and energy saving cement of high-quality.