Red clay application in the utilization of paper production sludge and scrap glass to fabricate ceramic materials

• Paper production sludge can be used as raw material for ceramics fabrication.
• New ceramics outclass mechanical properties of conventional materials.
• We studied new materials' structures by XRF, XRD, SEM and EDS methods.
• New structures were presented by glassy substances and some new crystalline forms.
• Industrial waste utilization provides high ecological and economic efficiency.

The article describes the compositions with red clay, as principal component, for utilization of paper production sludge and scrap glass to fabricate red ceramics at sintering temperatures of 700°, 800°, 850°, 900°, 1000°, 1050° and 1100 °C. The raw and final materials were analyzed by XRF, XRD, SEM, EDS and LAMMA methods. The flexural strength tests of obtained ceramics reached till 11.7 MPa, water absorption till 12.6%, bulk densities varied from 1.79 to 1.86 g/cm3, and shrinkage till 1.4%. These properties can be attributed to the sintering at 700° and 1100 °C of ceramics with glassy structures and small inclusions of new crystalline minerals, such as mullite, albite, orthoclase and nepheline.