The effects of deaeration on both the discharge and conveyance of fine powders were experimentally investigated. For this experiment, a novel screw feeder which the powders could be deaerated with was assembled and used.
As a result, the discharge rate of the fine powders from the screw feeder increased with the deaeration pressure. This is due mainly to the increase in the bulk density of the powders because of the mechanical force in the screw. A correlation of the discharge rate with deaeration was proposed within the operating range.
The performance of conveyance with deaeration was determined by the sliding rate of the powders on the inclined belt conveyor. The degree to wihich it slid decreased by treatment with deaeration under some conditions.

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The flow characteristics of fine particles in a spouted bed with a draft tube have been studied by measuring the solid hold-up in the draft tube, the bypass flow rate in the annulus, and the solids circulation rate. It was found that the gas-solid flow in the draft tube was the transport bed at high total gas flow rates.
The bypass flow rate in the annulus decreased with the total gas flow rate to a minimum and then increased with further increase in the flow rate.
On the other hand, the solids circulation rate increased with the total gas flow rate to a maximum and then decreased with further increase in the flow rate.
An empirical equation for the maximum solids circulation rate was proposed, which almost agreed with the measued ones.

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Glass beads were coated in a vibro-fluidized bed by atomizing a fine silica powder and polyvinyl alcohol solution. The coating efficiency and weight fraction of the agglomerated particles were measured under various experimental conditions, and their dependencies on the amplitude and frequency of vibration were investigated. When the humidity of outlet gas was high, the high coating efficiency and the agglomeration of core particles were observed. The efficiency of the powder coating decreased as the amplitude and the frequency increased, while agglomeration was prevented by the addition of vibration. It was confirmed that coating with high quality and high efficiency, where few agglomerates were produced and silica powder was utilized efficiently, was possible using the vibro-fluidized bed with adequate amplitude and frequency.

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The effect of organic binder adsorption on the rheological behavior of aqueous silicon nitride suspensions was studied to find the optimum powder characteristics for forming. The adsorption isotherms of polyvinylalcohol (PVA) in the suspensions were of the Langmuir type. The Si-OH group on the surface of silicon nitride particles decreased markedly due to the adsorption of PVA. This suggested the adsorption on the Brønsted acid points of the particles. The viscosity of the suspensions was controlled by the adsorption of organic binder on silicon nitride particles. The low binder affinity powder was suitable for preparing a suspension with low viscosity at high binder content in the suspension.

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The effect of surface treatment on the properties of granules of fine TiO₂ powders treated with water vapor and agglomerated by Pressure Swing Granulation was investigated. It was found that when the number of OH groups and water molecules on the powder surface was increased, the cohesive force between the particles became stronger, and large granules were obtained. Furthermore, the value of cohesive force between the particles in this study was close to the value of van der Waals force calculated based on the assumptions that the distance between particles is 1.5-4.0Å and that the force includes the polarity effect of the adsorbed water molecules.

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In order to form small spherical composite granules continuously by a simultaneous operation of granulation, grinding and separation using a single rotating conical vessel with a grinding media, experiments were carried out with CaCO₃ and SiC powder as binary solid materials, and with water as binder.
It was confirmed that the size of the composite granules decreased with increase in the feed ratio of binder to powder, and the size of SiC agglomerates contained in a composite granule depended on the volume fraction of the SiC component in the granule.

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Surface-treated microfine cements were prepared as a grouting material for use in a cement powder grouting method. This method is used in dam foundations that are hardly permeable to cement slurry. Laboratory test results revealed that decrease in the amount of size fractions coarser than 10μm and finer than 1μm in surface-treated cements remarkably improves the permeability of sand specimens. By using the cement powder grouting method with such a cement, a remarkable improvement in the water tightness of dam foundations with minute pores that are hardly permeabe to cement slurry can be achieved.

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The wettability and surface structure of precipitated silica surface loaded trimethylsilyl groups were investigated. By measuring water and nitrogen adsorptions, it was found that the non-treated sample had micro pores. The pores of diameter less than 0.8nm were not modified, while the pores of diameter from 0.8 to 0.9nm were modified by trimethylsillyl groups and closed by them. From these results, it was assumed that the former pores would become sites for water vapor as surface silanol groups after modification, and the latter pores would be independent of water adsorption. The character of the bare silica surface disappeared above a surface conversion rate of 33%. These results are deduced from a neopentane adsorption experiment. Furthermore, the water a adsorption capacity near the saturated pressure, as an index of micro-wettability, did not reach theoretical monolayer capacity above the same conversion rate (33%). It was also indicated that the preferential dispersion property as an index of macro-wettability drastically changed at a conversion rate of about 33%. From these results, it was demonstrated that the wettability is closely related to the surface structure interfering with the adsorption of water.

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A series of wet grinding experiments by a vertical type planetary ball mill with various composite grinding balls were carried out using calcite powder as the sample. From comparison of particle size distribution of the ground products using monosized grinding balls and composite grinding balls, it was found that the grinding rate for composite grinding balls of q=0.1-0.3 was improved by 27% compared with that of the small monosized grinding balls of d_B=2.58mm. The possibility of improvement was also confirmed from the experimental data using a high-G planetary ball mill of 150G.

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