Study of Taza's Miocene marl applications in heavy clay industry

The Miocene marl (MM) or calcareous clays in the southern Rif groove is one of the geological resources located in the region of Taza (Morocco). The aim of this work is to investigate the use this widely available raw material as an alternative resource in the heavy clay industry. For this purpose, physical, chemical (X-ray fluorescence, XRF), mineralogical (X-ray diffraction, XRD), microscopic analyses (SEM, petrography), and thermal analysis (DTA-TG) coupled with Fourier transform infrared spectroscopy (FTIR) were performed on the raw material. Analysis of the fired samples was carried out through optical microscopy and geotechnical tests. Geochemical analysis reveals that major constitutive elements as oxides are mainly SiO2 (similar to 47%), Al2O (similar to 14%), and CaO (similar to 7%). Mineralogical analysis shows that the marl includes low content (similar to 26%) of clay minerals (illite, smectite, and kaolinite), whereas non-clay minerals (quartz, calcite, and dolomite) make up to similar to 73%. In order to evaluate the performance of MM in heavy clay industry, the test data were analyzed according to reference diagrams from literature. The results from ternary diagrams indicate that the raw material falls inside the bricks industrial domain. In addition, tests performed on the product show that the raw material can be used for bricks manufacturing, including the adequate firing behaviour (red bricks) and required mechanical strength (18 to 21 MPa). Hence, bricks firing at 900 degrees C provided suitable mechanical properties rather than that fired at 1000 degrees C and 1100 degrees C.