The pneumatic conveying dryer which was mentioned in the previous report, was found of practical use from the results of basic and industrial applied experiments.
From the results of the experiments, the optimum operating conditions were obtained.
The test material could be dried from 2% to 0.2% water content under the following operating conditions; feed ratio below 1.0, air temperature above 100°C, air velocity over 40m/sec. The power consumption and dried material temperature was 60KWH/T and aboye 50°C respectively.
Size reduction of crystals occured noticeably near-by the inlet while it was considered regligible when air velocity was less than about 20m/sec.
For the length of the drying column, five meters was found enough. Adhesion of impurities inside of drying column was little, when the water contents of materials dried were less than 2% and impurities below 0.8%.

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塩化カリウムを水溶液の冷却法により晶出させるとき,(Na PO₃) nとMnCl₂とを少量添加しておくと, 八面体状のKClの結晶が得られ易い. その際, 添加物は次ぎの作用をなす.
1. 添加物は結晶内に入り, 全体に分布しているが, 均等ではない.
2. 添加物の溶液中の初濃度が増えると, 結晶中に入り込む量も比例的に大きくなる. 初濃度を (NaP0₃)n 35m·mol/kg H₂0, MnCl₂ 3.5m·mol/kg H₂0 程度に上げると結晶中のN(aPO₃) n とMnCl₂との割合, P0₃/Mn=10mol ratioとなる. それ以上の初濃度では, この比は余り変らぬ.
3. 添加物が結晶中に入り込むと, 格子ひずみが起る. 含量が増すとひずみも大さくなるが, 上の初濃度以上では, ひずみは余り大きくならぬ. この点は単結晶状の大きな八面体状結晶の得られる所である.

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In our country a lot of natural-gas brine, about 1,000,000 m³/day, is pumped out. It contains the same amount of NaCl and much less Mg²⁺ and Ca²⁺ compared with sea water, and nearly no SO₄^2-. So, it must be a good raw material for salt making. In this paper, isothermal evaporation of such brine at 25°C was studied. For this purpose, the data of the heterogeneous equilibrium of the five components system, NaCl-KCl-MgCl₂-CaCl₂-H
2O were found in the table of D' Ans and the diagram was drawn on a tetrahedron axis, and the change of composition of the liquid phase due to evaporation was computed graphically. In such a way, only 6 species of salt crystals were found to come out by evaporation, namely, NaCl, KCl, MgCl₂·KCl·6H₂O, MgCl₂·6H₂O, 2MgCl₂·CaCl₂·12H₂O and CaCl₂·6H₂O. The amoumt of water to be evaporated, the amount of crystals deposited, the amount and composition of the mother liquors obtained and the composition of the crystals gain was calculated.
The authors concluded that such brine was very suitable for salt making, because more and purer salt could be obtained compared with sea water.

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The boric acid contained in bittern is absorbed in magnesium hydroxide that is precipitated from the bittern.
The present investigation was performed with particular emphasis on the various conditions of this reaction in order to utilize boric acid in bittern. The experimental results are as follows:
(1) The pH value has a remarkable effect on the absorption. When the pH was below 11, rate of absorption was high, and when its range was from.11 to 12, it was low. When the pH was above 12, absorption did not occur.
(2) The relationship between the amount of absorbed boric acid and its degree of concentration agreed with Freundlich's absorption isotherm.
(3) The effect of temperature was not so remarkable.
From the foregoing, it can be concluded that this reaction is applicable to the collection of boric acid from bittern or the production of magnesium hydroxide containing boric acid.

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Permeability of calcium ions across heterogeneous ion exchange membranes prepared from pulverized ion exchange resins was examined together with sodium ions by the use of a seven compartment cell.
Each compartment, alternately separated by cation and anion exchange membrane, was previously filled with the raw solution (mixed solution of NaCl and CaCl₂), and electrodialyses were carried out for three hours. Both ions of the sample solution of the concentrated center compartment were determined.
Permselectivity of calcium ions against sodium ions is usually larger than unity under the conditions that sulfonic and carboxylic type cation exchange resins are used as raw materials for the membranes.
Permselectivity of calcium ions shows decrease with the increase of current densities and total concentrations of raw solutions.
Permeabilities of calcium and sodium ions across sulfonic acid resin membranes are larger than those across carboxylic acid ones. At pH of the neutral medium, the permeabilities of both ions are maximum.
Permselectivity of calcium ions against sodium ions across carboxylic acid resin membranes is smaller than that across sulfonic acid ones, and these results show that there are some binding forces besides the Coulomb forces between calcium ions and carboxylic acid radical.

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We investigated the change of physical and chemical properties of various soils by admixing common salt.
The soil samples were Sand, Loam and Clay, and the quantities of salt 1, 3 and 5 weight percent.
Subjects of experimentation were as follows; Grading-test, consistency-test, expansion and shrinkage-test, shear-test and compaction-test for physical properties, and ion-exchange in soils and eluviation of admixed salt on experimental roads at Matsuyama city, Ehime prefecture.
In consequence of admixing salt, the properties of soils changed remarkably.

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For the volumetric analysis of sodium precipitated as 1-naphthylamine-8-sulfonate, several bromination titration methods were examined. Bromine was supplied from bromate and bromide decomposed with hydrochloric acid. An indirect method of determining excess bromine iodometrically sometimes gives incorrect values owing to its difficulties in controlling the reaction and in determining the end point. Potentiometric titration procedure seemed to be preferable. Hydrochloric acid and bromate-bromide solution were used as a titre, respectively, and the latter was found to be superior when a solution not less than 0.05M in concentration was employed. Hydrochloric acid was found necessary to be added sufficiently, to be about 3.5N in concentration. The reaction temperature had important influences on the reaction velocity and forms of reaction products. The optimum temperature was 50°C, and substitution of more than 3 atoms of bromine per molecule of 1-naphthylamine-8-sulfonic acid became prominent at 70°C. Under the optimum condition, analytical results were within about±1% of the calculated figures.

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A method is described for complexometric determination of sulfate, in which the sulfate is precipitated as barium sulfate. The barium sulfate is filtered off and dissolved in an excess of standard EDTA solution in the presence of sodium hydroxide or diethylamine at pH 12-12.3, the unreact reagent is back-titration with standard calcium chloride solution, methylthymolblue being used as indicator.
The procedure is simple and rapid, and the end point is very sharp. The method has been applied to the determination of sulfate in common salt, bittern, sea brine and natural gypsum.

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