General properties of titanic acid, which was used as adsorbent of uranium in sea water in the previous papers, were investigated by X-ray diffraction, infra-red spectrum, electron microscope, thermoanalysis, electrophoresis and solubility in mineral acids. Four types. of titanic acid were prepared from titanic sulfate by the following procedures;neutralization at room temperature (I) or at boiling temperature (II), and homogeneous precipitation with ammonium acetate (III) or urea (IV).(I),(II) and (III) were bulky, fibrous and amorphous, containg a large quantity of adsorbed water.(IV) was, however, powderlike cubic crystal. Regardless of the types, solubility of titanic acid in hydrochloric and sulfuric acid was dependent on the concentration of the acids and temperature. Although (I) was soluble in the acids at room temperature the solubility decreased gradually as time proceeds. Surface charge of the titanic acid in sea water was negative. The experimental formula of those types were (I) TiO23/2H2O,(III) TiO25/3H2O, and (II) and (IV) TiO2H2O, respectively.
In case cation-exchange resins of H-Na and H-Ca forms are analyzed by DTA and TGA, desulfonationkes place only for H-form ion-exchange resins. Therefore, the authors took advantage of thisharacteristic behavior to study a quantitative determination method of free sulfonic group. Also, hey estimated separation factors SHNa and SHCa by this method, and confirmed that those values esulted from this method agreed with those obtained by the conventional methods.
In a multi-stage flash distillation (MSF) plant which produces fresh water from the sea, the brineeffusing from each flash chamber does not reach the equilibrium state, although it lowers theemperature due to adiabatic pressure drop. The author defined that the non-equilibrium temperature difference (ΔNTD) was the difference between the temperature of effusing brine (TB) and the temperature of saturated steam (TS) plushe boiling point elevation of the brine (ΔBPE) that is ΔNTD=TB-(TS+ΔBPE) Furthermore, the author studied on equations for mass and heat transfer phenomena in a MSF plant, and obtained as the result the equations for the calculation of the optimum performance ratio,ηHOPT and the minimum production cost of fresh water, Cmin. Using the equations and parameters for the plant and the cost shown in Table-1,ηHOPT and Cmin were calculated with a computer, and the effects of ΔNTD on ηHOPT and Cmin were estimatmted.
The decarboxylation temperature of CO2 dissolved in pure water and artificial sea-water was investigated to clarify the formation mechanism of scale which is educed as CaCO3 and Mg (OH) 2in the process of desalination dy multistage flash evaporation method. In this study, the decarboxylation temperature was determined by the differential thermal analysis (D. T. A.) instrument with a glass thermistor, which was superior in detecting the thermal reactionin the solution around the room temperature. The decarboxylation of CO2 occurres at 18.0°C in the artificial sea-water and at 31.5°C in the pure water.