Abstract

The Kraft process-based paper production generates considerable amount of waste. The chemical recovery section produces lime sludge while fly ash is being generated in the boiler through combustion of biomass for electricity production. The final utilisation of such waste materials is significant concern, since landfilling is becoming less effective destination due to strict environmental regulations. Determined by this scenario, industries are considering more sustainable solutions, such as application of waste material in manufacturing of distinct products. In this work, the lime sludge and fly ash tested as raw materials for cement clinker synthesis and mortar preparation from synthesised cement clinker. Firstly, the detailed characterisation of waste materials was performed, on the basis of characterisation distinct mixtures of materials were prepared. The formulated mixtures then fired at 1000 ºC and 1100 ºC to get cementitious clinkers. The clinker was processed at relatively lower temperature than generally used in the industrial synthesis of clinker due to the presence of mineralising impurities in fly ash and lime sludge. The cement was prepared from the synthesised clinker and applied to produce the mortars that advanced in adequate mechanical strength and did not divulge signs of deterioration or durability weaknesses.

Keywords: Paper industry; Waste materials; Lime sludge; Fly ash; Clinker; Cement; Mortar