Utilisation of municipal solid wastes for mortar production

In this study we examined the thermal co-processing of municipal solid waste (MSW) and other raw materials needed for the production of clinker, and consequently of mortar, without causing environmental problems. The technique is related to a method of manufacturing mortar by firing at high temperature a mixture of mineral raw materials (limestone, clayey materials, silicates and iron oxides) together with dried and properly treated solid wastes, according to the Greek Patent 1003333. The MSW is separated into two fractions; the heavy one containing mainly earthen materials, stones, broken ceramics, glass and other similar materials and the light one containing mainly paper, wood, light plastics, leather and cloth pieces, various fibres and other similar combustible materials. The dried and crushed heavy fraction is introduced directly at the 1100 °C zone of a specific two stages rotary kiln, where it meets the mixture of the mineral raw materials. The light fraction is used with a mixture of pet-coke, in an appropriately designed jet burner to heat the rotary kiln. The clinker obtained is milled together with gypsum to produce a hydraulic mortar for building applications. The main advantages of the method are the significant volume reduction of municipal solid wastes by incineration without toxic gas emissions and the production of a valuable material. An economic analysis and evaluation was carried out. It was concluded that the installation of a unit, treating 500 t/day of MSW and producing about 433 t/day of mortar, seems to be economically profitable.