New Clayey Deposit and Their Potential as Raw Material for Red or Structured Ceramics: Technological Characterization.

Mineralogical and technological characterization of ceramic raw materials from a new deposit located at Caxias city, Maranhão State-Brazil, was accomplished to determine their potential as raw materials for the ceramics industry in northeastern Brazil. The ceramic raw materials were collected from three different locations on the site and characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA), and thermogravimetry (TG). The XRF analysis of the fraction < 2 μm revealed that most samples had SiO (35-51 wt%), AlO (19-29 wt%), FeO (2-21 wt%), MgO (0.7 to 4.5 wt%) and KO (0.9 to 5 wt%) as components. Quartz, kaolinite, illite, hematite and montmorillonite were the main mineral phases identified. DTA and TG analysis confirmed the mineral identification. The technological potential of the ceramic raw materials was investigated by: cation exchange capacity (CEC), plastic behavior (Atterberg Limits), linear shrinkage at 950 °C (LS), flexural strength (FS), apparent porosity (AP), water absorption (WA) and bulk density (BD). The main experimental results-WA (9-17%), AP (19-31%), FS (2.0-23 MPa), and the Atterberg limits-indicated that the ceramic raw materials investigated have high potential to be used to develop mass for red or structured ceramics, such as bricks and roof tiles.