The present work aims to prospect and study the plastic and superplastic clay deposits in the state of São Paulo, Brazil, as a source of raw materials for the ceramic tile industry and especially for the production of porcelain stoneware tiles. To achieve the proposed objectives, a geological study was carried out through the mapping and identification of the present lithologies, lithogeochemical characterization using X-ray diffraction, inductively coupled plasma optical emission spectrometry, cation-exchange capacity and organic carbon and characterization of the ceramic technological properties, including granulometric analysis by sedigraph and Brunauer–Emmett–Teller specific surface area. According to their geological characteristics, the studied deposits were classified into two types: a detrital sedimentary deposit, restricted to Quaternary alluvial sediments and Neogenic Tertiary formations and composed of silt-sandy clay and plastic, kaolinitic, refractory and silico-aluminous facies; and an alterite type, found in Permo-Carboniferous rocks of the Paraná Basin, composed of laminated/massive weathering siltstones, with the highly plastic, fluxing clay minerals illite, kaolinite and smectites. Among the targets studied in these deposits, argillaceous facies with plastic and superplastic characteristics were identified, which affect their applicability in compositions for producing porcelain stoneware tiles and stoneware.

This study focuses on the mineralogical and geotechnical characterization of northern Moroccan clays from the Tangier and Tetouan areas and compares them with the main clay deposits used in the Moroccan ceramic industry (from Meknes, Fes, Salé and Safi regions). Sampled clays were analysed by X-ray diffraction on bulk and clay (<2 μm) fractions to identify the mineralogical assemblages of the clay outcrops. Further analyses were conducted to determine the particle size distribution (laser diffraction particle analyser), the total organic matter content (Loss- On-Ignition measurements) and the Atterberg limits of the raw clays. The study aims at investigating the spatial variability of the clay samples and at evaluating their potential application as raw materials in the ceramic industry.

Tetouan and Tangier clays are characterized by diversified mineralogical assemblages (in particular a variable proportion of clay, quartz and calcite) compared with the Meknes, Fes, Salé and Safi clays (high clay content, quartz and calcite). The clay fraction of the Tetouan and Tangier samples is dominated by illite and kaolinite with variable amounts of chlorite, smectite and/or vermiculite. Illite is the dominant phase in the Meknes, Fes, Safi and Salé clays, but is associated with kaolinite. No direct relationship between the mineral assemblage composition and the lithology of the series was found.

The clays materials studied consist generally of fine particles with medium to high plasticity and low organic matter content. Due to their mineralogy, grain-size distribution and plasticity the clays appear to be suitable as raw material for the growing Morocco ceramic industry.

The present study focused on the assessment and possible applications of the clay from the Miličinica deposit, western Serbia. X-ray diffraction (XRD), Infrared (IR) spectroscopy, Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Differential Thermal Analysis and Thermogravimetry (DTA-TG) and High Temperature Microscopy (HTM) were used to characterize the clay in question. The physical properties determined were colour, plasticity, specific surface area, particle-size distribution and cation exchange capacity (CEC). Clay minerals are the main phases in the samples studied, with illite being the predominant phase and kaolinite being present in variable amounts. Quartz, feldspars, carbonates and iron-bearing minerals were also detected. Varied technological behaviours were expected because of the mineralogy (illite and iron contents), average grain size (0.6–0.7 µm), specific surface area (≈60 m2/g) and plasticity index (≈13%). The classification of the clays studied, based on the main characteristics and using appropriate diagrams, suggests that they are easily adaptable for ceramic processes.