In running the demineralization or the concentration of electrolyte solution by electrodialysis by using ion-exchange membrane, the permselectivity between the same charge ions through ion-exchange membrane is an imporant factor. The present investigation was undertaken to determine the permselectivity of Cl- and OH- thnough anion-exchange membrane in ion-exchange transfer and to make a comparison with the Permselectivity in case of electrodialysis. As the result, it was found that the permeabilities of Cl- and OH- were about the same and that these values were very little affected by the concentration and composition of Cl- and OH- in the original solution. These results were similar to those in the electrodialysis
The present study is connected with the utilization of gypsum by-produced in the process of manufacturing sea-salt gypsum for gypsum cement. Insoluble anhydrite (II-CaSO4) was calcined at 800°C to prepare its sample from sea-salt gypsum. Then, the authors investigated, in accordance with the experimental design, effects of several kinds of accelerator for hardening and ageing conditions upon the setting time, the strength and the hydrating degree of cement. The following results were obtained: 1. The setting time of cement was the shortest when 1 wt% of potassium sulfate was added. 2. The strength was affected by the ageing conditions. 3. The strength was not always large even if the hydrating degree of cement was high.
This paper reports the results of a study conducted on the electrophoretic concentration of sea water utilizing the ion-exchange membranes prepared by “Paste method”. In this study, the authors measured those influences to be exerted by the temperature, the flow rate, the concentration and the current density of sea water upon the results of the electrophoretic concentration of sea water. Also, the authors investigated the cell voltage, the composition of the concentrated sea water and the current efficiency, and discussed them in relation to the concentration polarization developed on the sea water side of the ion-exchange membranes.
The authors made a study on the electrophoretic concentration of sea water by using the ionexchange membranes prepared by “Paste method”. As a result, they derived from the characteristic properties of the membranes, the theoretical relations which expressed the concentration and the flow rate of the concentrated sea water, the current efficiency and the cell voltage. Also, the authors measured those influences to be exerted by the species, concentration, temperature, current density, agitation degree et al of the solution upon the characteristic properties of the membranes. By using the characteristic propertiis of the membranes and the theoretical relations obtained, the authors calculated the results of the electrophoretic concentration of sea water, and made a comparison with the experimental results reported in their previous paper. As a result, a reasonable agreement was found between these results.
We studied on the crystal growth of dichloromonofluoromethane hydrate when dichloromonofluorometane liquid evaporates contacting with sea water directly in the continuous flow type, propeller stirring vessel. As the operating conditions such as amount of heat removed from the system, average circulating time of crystals in the vessel and solid content in the slurry being experimental factors, their effects for the average particle size and linear growth rate of crystals which were calculated from particle size distribution was determined. Results were summerized in the forms of following equations. Dm=0.18 tm1/3 Dm=0.17 C1/3 Q-1/3 u=0.2C-2/3 Q2/3; where Dm: average particle size (mm), tm: average circulating time (hr), C: solid content in slurry (%), Q: amount of heat removed from the system (kcal/hr l), u: linear growth rate (mm/hr). They means that the particles having the size required on the separation process was able to produce by selection of operation condition in the crystal formation process.