Shinzo Okada

Mass Transfer and Current Distribution under Free Convection Conditions

Correlation of mass transfer with current distribution, for deposition and dissolution of metals, on vertical electrodes, under free convection conditions, is discussed. The equation of mass transfer and the Laplace equation, determining the concentration and potential distributions, respectively, are solved simultaneously. The results explain most features of observed current distributions.

Effect of the Walls of Electrolytic Cells on Current Distribution

The field in the rectangular cell with two parallel and flat plates as electrodes has been analyzed. In this paper, no consideration is given to polarization phenomena for mathematical convenience.As a numerical example, current distribution at the suiface of the electrode has been calculated in detail for the special case where distance between electrodes equals cell width. Moreover, diagrams are given to show numerical relations such as the ratio of current on inner and outer surfaces, total current distribution over the electrodes, etc., for the general case.

黒鉛電極に関する研究 (第4報):硫酸塩水溶液電解においての人造黒鉛陽極の膨潤および崩潰について

We have investigated on a rapid method of estimating the life of anode graphite at the amalgam process chlorine-caustic cell, by electrolysis of sodium sulphate solution and by electrolysis of sodium chloride solution containing sulphate.This method is based on our researches about the mechanism of corrosion of anode graphite described in the previous papers.That is to say, the corrosion in electrolysis of sodium sulphate solution under conditions of above 40°C, acidity of below 1N, and anode current density of above 5amp/dm2, and that at the amalgam process chlorine-caustic cell were of just the same mechanism, namely, the pure chemical oxidation consumption from surface of graphite crystal.The following methods were found preferable:(1) The sodium sulphate solution electrolysis method for the domestic anode graphite:The corrosion rates in mg/Ah unit of anode graphites treated for 3 hours under electrolytic conditions of sulphate concentration of Na2SO4·10H2O 100g/l, 60°C, anode current density of 10amp/dm2 are compared with each other.This method was found to be better than the other method for the domestic anode graphite.(2) The rapid method, combining electrolysis of sodium sulphate solution with electrolysis of sodium chloride solution containing sulphate, for domestic and A chesons anode graphites:The anode graphites were treated preliminarily by the above-mentioned sulphate solution electrolysis, and then treated intermediately for 2 hours under conditions of 60°C, acidity of pH 2 to 3, and anodic current density of 50amp/dm2 with sodium chloride solution of concentration of NaCl 260g/l contained sulphate of Na2SO4 25g is one liter of brine.In the last formal electrolysis, the samples are treated for 4 hours under the same condition as intermediate treatment, and the corrosion rates which were measured as difference of weight in this formal electrolysis are compared with each other.This method resulted in the best coincidence with the order obtained in long time test by amalgam process chlorine-caustic cell as for the domestic and Achesons anode graphites.

Free-diffusion Type Calomel Electrode

ガラス電極で塩濃度の小さい溶液のpHを流動下で測定する場合,しばしば測定pHの変動という障害に遭遇する。従来,専ら使用されているピンホール型およびスリーブ型甘コウ電極について,この原因を調べ,液絡部における流動電位と解した。このような点から,被測液を直接飽和塩化カリ溶液に接触させる比較電極を試作し,満足すべき結果をえた。なお,0℃で飽和塩化カリ溶液になる3.3N塩化カリ甘コウ電極の標準電位差を測定し,0.2551-0.00039(t-18)V(tは摂氏温度)なる値をえた。

A New Gas Method for the Determination of Metallic sodium

The analysis of metallic sodium heretofore has been made by the titrimetric method, employing its solution oxidized by alcohol. In using this method unsatisfactory results have been obtained, which are due to the presence of NaOH as an impurity. Therefore a more accurate method to determine the amount of hydrogen produced by the oxidation of sodium with alcohol has been carried out. In this method, the presence of NaOH or Na2CO3 in the metal does not cause any error. Since the gas analysis requires careful caution for the measurents of the gas volume which is sensitve for the change of temperature and pressure, the necessary apparatus and reagent have been investigated. The method can be operated simply in a short time with better accuracy than the titrimetric method. A table for correction of the volume of gas is presented in order to make a rapid calculation. The standerd deviation of measurements was 0. 009 % and it showed higher accuracy than the titrimetric method.

On the Compressibility of Suspended Particle

In this paper, a new relationship between compressibility of suspension and those of its components were led considering the effect of the interfacial actions at the surface of suspended particle.The approximations, showing us the possibility that the compressibility of suspended particles could be determined graphically, were obtained by using some assumptions and were verified experimentally by measurements of sound velocity in suspension and its density.The value for the compressibility of the particle in question derived from these approximations with the suitable quantity of the constant “p” was in good agreement with the values obtained by another investigators.

On the Determination of Water in Mineral Substances

We made studies on the method for determining the total water content, hygroscopic and combined, of the mineral substances. The analytical train consists of a purifying and drying train, a combustion tube-mounted in a high-temperature furnace and an absorption train. As oxygen is liberated and oxidizes ferro alloy and metal in samples by decomposition of the water contained in them due to the high temperature, the real water content can not be determined. Therefore, oxygen as the sweeping medium which passes successively through the train, was selected in order to avoid any such reaction occurring within the train. On this method the blank test was the most important and was investigated to establish satisfactory results for determining the total water content in the mineral substances. The results presented also confirm the reproducibility of the method described herein.

Studies on the Graphite Electrode, 1

The degree of graphitization of artificial graphites was estimated by the anodic swelling in electrolysis of sulphuric acid and Brodies wet-oxidation. Moreover, the mechanism of the corrosion of graphite was discussed.The results obtained are as follows;1. Swelling test:Swelled graphite by anodic treatment with sulphuric acid evolved oxygen when it was digested in alkaline solution, and the volume of oxygen suggested the degree of graphitization.2. Wet-oxidation test:Generally, lower graphitized carbon (amorphous carbon) consumed more than higer one (graphite).In artificial graphite, however, contrary to our expectations, higher graphitized graphite consumed more than lower one.The above facts availed for the estimation of the degree of graphitization.