A review on use of municipal solid waste ash in concrete

摘要

It could be a possible replacement of raw material in Portland cement production. R. Kikuchi has shown that the addition of MSWI ash for clinker production will shorten the setting time and decrease workability; he suggested that a delaying agent like gypsum should be added. Cement production consumes huge quantities of energy and emits large amounts of carbon dioxide, which is the major cause of global warming. One of the advantages of using MSWI ash as raw material for cement is the reduction in carbon dioxide emissions, thus minimizing the global warming effect. Due to the fact that MSWI bottom ash and fly ash are composed of lime instead of calcium carbonate, use of them in cement production can reduce the carbon dioxide emission. There are several technical problems discouraging this application; the high chloride content will affect the product quality, and the cycling effect in the cement kilns will cause rapid clogging and corrosion inside the heat exchangers. Pre-treatment of fly ash is recommended to remove the chloride and heavy metals content, also the quantities of MSWI ash added to the process should be carefully controlled in order to ensure the process safety as well as product quality.