A New Approach for the Management of an Industrial Waste: A Case Study

Abstract

In recent years, industrial production has significantly increased and with it the amount of waste. For its management, the governments’ strategy is directed towards the reuse of the industrial waste for various benefits. Firstly, it reduces the impact on the environment. Secondly, the space of the landfills does not get over utilized. Thirdly, the natural resources are preserved and/or the import of the raw materials is reduced. Geopolymer materials have emerged as a possible solution for the valorization of industrial waste, especially the aluminosilicate industrial sludge. The sludge used in this study is generated during the treatment of industrial wastewater of a local ceramic factory. The aim of this paper is to study the relation between the material compressive strength and the quantity of silicon ion dissolved at early stage of geopolymerisation, in order to understand the effect of the dissolution rate on the development of compressive strength of an industrial sludge based geopolymer. To achieve our goal, the geopolymers samples were synthesized by adding sodium hydroxide solutions with different H2O/Na2O molar ratio (10, 11, 12 and 13) to the calcined industrial sludge. The obtained paste was poured into cylindrical PVC molds and cured at room temperature under atmospheric pressure for 7 days, then at 65 °C for 20 h. The reaction of calcined industrial sludge and NaOH leads to the formation of a new phase rich in Aluminum. The dissolution of the calcined industrial sludge increases with the decrease of H2O/Na2O molar ratio. The compressive strength of geopolymer material increases with the increase of the dissolution rate. According to the results in this work, the study proves the possibility of using the industrial sludge for manufacturing geopolymer-based materials.