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A soil's physical properties, mineral types, and pore structure significantly influence the shape and properties of the soil-water characteristic curve (SWCC). This study investigated the effects of the soil's physical properties and mineral types on the SWCC and pore-size distribution (PSD). Eight different soils from an alluvial deposit in Istanbul and Adapazarı/Türkiye were used in the study. The test samples were prepared by compaction at optimum water content (OWC) and wet side of optimum water content (wet of OWC). The samples were prepared by consolidation from the slurry. The PSDs of the samples were calculated using the SWCCs and evaluated with scanning electron microscope (SEM) analysis. In addition, the mineral types of all soils were determined by X-ray diffraction analysis. The soil which contains illite-type minerals has higher matric suction than containing kaolin-type. The effect of the clay percentage is more pronounced in silty soils than in plasticity and activity. Soil suction increased with decreasing compaction water content in clayey soils. The air entry water contents rose as the void ratio, liquid limit, clay content, and plasticity increased. The compaction conditions affected the macropore structure more than the micropore structure. In addition, the ratio of macro-micro pore sizes increased with the rise of the compaction water content. [ABSTRACT FROM AUTHOR]

Clay minerals need to be dispersed with blungers before their utilization in the related industries due to their plastic properties, and size reduction is carried out in a wet medium. Clay minerals also contain impurities such as nonplastic materials in their structure. Mechanical dispersion parameters are important in the separation of clay group minerals (halloysite and kaolinite) from their typical non-clayey gangue minerals (quartz and goethite). In this study, the removal of impurities from halloysite ore obtained from Kızıldam, Turkey, was examined in terms of mechanical dispersion parameters, namely, feed size, blunging time and speed, pulp concentration, pulp temperature, and the aging process. The effect of these parameters on halloysite dispersion was determined by particle size, chemical, and mineralogical analysis, and optical and scanning electron microscope images. The results obtained from the studies of the mechanical dispersing and particle size distribution of the products indicated that the optimum dispersion parameters were determined as −10 mm feed size, 8 h, and 1000 rpm blunging time, and speed, 35% pulp concentration at 25 °C pulp temperature. Under these optimum conditions, a 72.3% amount of −38 μm clay product containing 35.6% of halloysite, 46.5% of kaolinite, 12.0% quartz, 1.9% goethite, 0.9% gibbsite, and 3.2% other minerals were obtained from the halloysite ore, having 30.5% of halloysite, 43.4% of kaolinite, 19.1% quartz, 2.9% goethite, 1.4% gibbsite, and 2.7% other minerals. In this study, it was understood that feed size, pulp concentration, blunging time, and speed were important parameters, while pulp temperature and the aging process had no significant effect on the mechanical dispersion of Kızıldam halloysite. In addition, impurities such as quartz and iron-bearing minerals were separated from the ore by blunging and sieving. [ABSTRACT FROM AUTHOR]