The charging behavior of various oxide particles was investigated using the zeta potential, which is affected by the electronegativity of the metal ion in an oxide and the properties of the solvents. Acetone, methylethylketone, cyclohexanone, ethanol (EtOH), 1-propanol (1-PrOH) and 1-butanol (1-BuOH) were used for the bath. In the case of the I2-added ketone bath, the H+ ion concentration increased with increas ing I2 content. The zeta potential of the various oxide particles was changed to positive. The zeta potential of the oxides was large in the high H+ ion concentration bath. Accordingly, the positive charged oxide par ticles were attributed to the adsorption of H+ ion onto the particles. In the case of alcohol, included H2O generates H+ and OH-by electrolytic dissociation. Therefore, the zeta potential becomes large in the case when the electronegativity of the metal ion in oxide is low, and the H+ ion behaves as a potential determin ing ion.

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A numerical calculation method of the fluidized bed calciner for cement production including pulverized coal combustion, raw material decarbonation reaction and heat transfer was developed using the coupling simulation method of DEM -CFD (Discrete Element Method -Computational Fluid Dynamics). In addition, in order to shorten the calculation time, a coarse-grained model for DEM was used in the DEM-CFD. Based on this, the influence of the position and the number of pulverized coal blowing lines into the calciner on the characteristics of pulverized coal combustion and the property of raw material decarbonation was investigated. As a result, a modification plan to change pulverized coal blowing lines to promote pulverized coal combustion and raw material decarbonation was found from the calculation results, and the position and the number of pulverized coal blowing lines were changed from a single pulverized coal blowing line to two blowing lines in a commercial manufacture system. Then, the modified effectiveness and the validity of the numerical calculation method were verified by measuring actual gas composition and temperature distribution in the calciner before and after modifying.

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