Masaharu Yamada

Kinetics of dissolution of noncrystalline oxides and crystalline clay minerals in a basic tiron solution

The dissolution behavior of five noncrystalline oxides, montmorillonite, kaolinite, chlorite, and sepiolite in a basic tiron solution was studied at pH 10.5 and 80°C. The results show that for montmorillonite the concentrations of Al and Fe ions dissolved in the treating solution were diminished because of cation-exchange reactions of the sample in the suspension. To explain these observations, a mass-balance equation for the specified cation in solution was formulated, which consisted of both a dissolution term and an ion-exchange term. The several parameters of this differential equation were fitted to allow the calculated results to represent the experimental findings. Using these values, an equation lacking an ion-exchange term was also solved numerically. Thus, a dissolution curve was described, which would have been obtained had no cation exchange taken place. From these equations, the error resulted from the cation-exchange capacity of samples in chemical dissolution methods can be evaluated. According to this estimation, and assuming the value for a 1-hr treatment, an error of about 15% was determined for the amount of noncrystalline components contained in the specimen in this investigation.

On the One Dimensional Transmission Properties of the Bulk Density in Mobilized Particulate Materials inside an Inclined Tube

The behavior of particulate materials in general particulate processes can not be discussed without the consideration of dynamic factors. For example, if the discharge valve of a particulate hopper is opened, it will be observed that the discontinuity boundary of the bulk density is transfered upward in it storage. This phenomenon is expected to be solved as one of the most urgent problems for the establishment of the systematic design method of a discharge valve, but has not been elucidated yet. From this standpoint, in this paper, the transmission mechanism of the bulk density in mobilized particulate materials is fundamentally and experimentally discussed. As a result, it is pointed out that the bulk density in mobilized particulate materials has the property of a kinematic wave.

Discussions on the existing particle density distribution formed around a single plunger due to its penetration

Abstract Existing particle density distribution formed around a plunger is discussed using X-ray radiographs. As a result, existing particle density is shown to propagate as a kind of dynamic wave in the powder layer. This suggestion is very interesting from the standpoint of the spatial particle density distribution in a powder layer. The main results of this study are as follows: 1. When a plunger is penetrated into a powder layer and is displaced in it, a periodical existing particle density distribution develops around the plunger. Such a density distribution can be regarded macroscopically as spatially uniform in regions relatively remote from the plunger, but periodically variable in the vicinity of the plunger head. 2. Analogous to wave phenomena, the low density zones manifest reflection at the walls, diffraction through a slit and interference between two slits. 3. It is pointed out that the rotational component of particle movement with regard to a macroscopic slip plane is a critical factor in determining particle density variations as well as in the phenomena of reflection and interference observed with the development of existing particle density distribution within a powder layer.