Alite and Belite obtained from the sludge of a paper recycling process

Abstract

In this work, the feasibility of obtaining Alite and Belite with possible applications in the cement industry from the primary sludge generated by a paper recycling industry in the State of Santa Catarina, Brazil was studied. The effect of the heat treatment on the physical and chemical properties of the primary sludge was studied, when treated at 800 °C, 875 °C and 950 °C, and defined by studies using the dilatometry technique. The treated sludge at these temperatures was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), thermal dilatometry (TD), X-ray fluorescence spectroscopy (XRF), surface analysis by the method of Brunauer, Emmett, Teller (BET), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed the appearance of the Alite and Belite phases with different proportions, depending on the temperatures used during the heat treatment processes and with sufficient quality for application in the cement industry, since the optimal condition to obtain Alite is the heat treatment at 950 °C. In addition, the temperatures used were lower than those used in the conventional processes of Alite and Belite.