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Behaviour of bentonite suspensions in non-aqueous media

Uskarcı, Togan
Bentonite is a smectite type clay mineral and swells in water. In this thesis, the effect of acetone, methyl-ethyl ketone, n-hexane on the properties of bentonite was determined by thermal analysis and water absorption tests. The tests indicated no significant change with treating bentonite with organic liquids. Because of the swelling property, only small amount of bentonite can be suspended in water. This may limit certain applications of bentonite. In this thesis, feasibility of suspending large quantities of bentonite in a non-aqueous media was studied. The concentrations for a pumpable high solid bentonite slurry were determined. As aqueous slurry showed pumpable properties up to 30-35 pounds/barrel, this concentration was as high as 125-150 pounds/barrel for acetone, 175-200 pounds/barrel for methyl-ethyl ketone and 325-350 pounds/barrel for n-hexane. Bentonite deposite has a complicated composition, containing free silica minerals, such as quartz, cristobalite, and opal; silicate minerals, such as feldspar, mica, and zeolite; carbonates or sulfates of alkaline earth metals, such as calcite, dolomite, and gypsum; and, in addition, iron compounds and humus. As mined it is primarily broken and dried and then pulverized by means of an attrition grinding machine. In this study dispersion of raw bentonite by high shear blending and shaking forces in the presence of acetone, methyl-ethyl ketone and n-hexane and eliminating the non-clay impurities by screening were studied. Many attempts have been made to provide a bentonite composition retaining the full swelling properties of the bentonite by the addition of non-aqueous liquids for obtaining a flexible waterproofing sheet. In this research the possible method for deposition of bentonite in a sponge by saturating the sponge with bentonite using organic liquids was investigated.