Recovering wastes from the paper industry: Development of ceramic materials

The continuous generation of industrial waste and the environmental problems it causes make it necessary to seek alternative methods for treating waste. The development of ceramic materials seems to be one such alternative. In this paper, we study the possibility of recovering two forms of waste from the paper industry, sludge from the purification of waste water and residue from cleaning the pulp. The sludge and residue can be used in ceramics, whose properties and composition permit the incorporation of such waste in their manufacture. This addition enables savings in both raw materials and energy, as these waste products have high calorific content. In both cases, the results show that increasing the content of waste increases linear expansion and water absorption and in turn reduces resistance to compression. The decrease in resistance to compression is more pronounced in the specimens prepared with paper waste than in those prepared with sludge. The results also show a decrease in thermal conductivity that is attributable to the lightening quality of both residues.