The aim of this study is to produce desiccant clay, one of an industrial product of bentonite, from a well known Ca-bentonite deposit in Turkey. The studied sample contains approximately 65-70% dioctahedral smectite (montmorillonite), 10-15% calcite and minor amounts of quartz, opal-CT, feldspar, zeolite and also 5% amorphous material. Following the characterization tests, size classification, beneficiation through hydrocyclone separation, utilization of some additives namely calcium chloride and heat treatment methods were applied to enhance the moisture adsorption capacity of bentonite to a desirable level. Studies on the determination of moisture adsorption capacities show that the original moisture adsorption capacity of untreated and clay without any additive is around 13 % (w/w). The particle size distribution of the clay has found to exert no appreciable effect on the moisture adsorption capacity. Addition of calcium chloride, upgraded the moisture adsorption capacity of the tested natural clay to the level of 33 % from a level of 13 %. The heat treated clay also indicated the optimum temperature of nearly 200°C, to obtain the best moisture adsorption capacities. The results reveal that the improvement in moisture adsorption capacity is roughly proportional to the level of impurity removal; the highest quality of hydrocyclone product yielded a desiccant clay of capturing 15 % (w/w) moisture without any additive.
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