The study was carried out to examine the most suitable conditions for separation and recovery fo gypsum by means of the flotation process from gypsum scale discharged from the vacuum evaporator in saltmaking plants.
Using a previously reported method, the wettability of saturated solutions for gypsum scales are examined qualitatively to know the best collector and experimental conditions. From the results, it was ascertained that an anionic surface active agent was preferable, and especially “Auxide”,“Monogen” and turkey red oil were the best collectors for gypsum.
Many flotation tests adding a kind of collector (various concentration) in an MS-50 Type flotation machine were carried out for the solid samples and their saturated solutions obtained through washing the gypsum scale 50gr.(Sample No.V) with an artificial sea water 220cc. The agreement between results of this test and those of quantitative wettability test are approxi-mately seen.
As the conclusion, it was indicated that the addition of 4cc of 2% turkey red oil solution as a collector, and the control of pH (about 8) of concentrates were important factors from a view of flotation efficiency. A representative result of flotation process is as follows:

抄録全体を表示

From the analysis of the precipitates and their mother licuids, it was found that the minimum concentrations of K⁺ at various temperature were conciderably high to precipitate the Engel salt from the solutions of various mixing rate of MgCO₃·3H₂O and KHCO₃. They were 0.7. 0.8 and 1.05g/100ml at the temperature of 0°, 5° and 15° respectively.
As to the effect of the other salts to the precipitation of Engel Salt, it was cleared that NaCl did not decrease the precipitation rate but retarded undoutedly the velocity of precipitation, although MgCl₂ and MgSO₄ decreased considerably both rate and velocity of precipitation. Perticularly the preventing action of MgCl₂ was intense, addition of 1% decreased about 10% of precipitation rate.

抄録全体を表示

In the quantitative determination of phosphate ion by the colorimetric method of molybdenum blue with the use of stannous chloride as a reducing agent, the conditions for this reaction have been investigated in detail and the following results were obtained.
(1) The temperature of reaction affected the intensity of coloration. The error was about 1%/1°C at around 25°C, and the determination became impossible at above 70°C due to the formation of white precipitate.
(2) The concentration of acid and the concentration of ammonium molybdate showed considerable influence on the intensity of coloration. Many experiments were carried out on these problems, and the relationships among these three factors are shown by a graph. The results indicated that the optimum condition of sulfuric acid for quantitative determination was 0.65 N and that of ammonium molybdate was 0.15%
(3) A change in the amount of stannous chloride added had pract ically no effect on the intensity of coloration.

抄録全体を表示

Many pieces of cubic gelatine gel containing 5% of ricinus oil were made in the glass apparatus (Fig. 1). Table salt mixed with the antioxidants, Butylated hydroxyanisole (BHA) and Di-butyl hydroxytoluene (BHT), was scattered on the gel, and the following results were obtained.
1. Table salt mixed with 1% of BHA or BHT and salt coated with 0.01 % of BHF showed a little obstruction to the salt parmeation in 20 hours after scattering.(Fig. 2 and Fig. 5)
2. Table salt mixed with 0.02% of BHA or BHT showed no such effect.(Fig. 3 and Fig. 4)

抄録全体を表示

pH of sea water, brine and bittern decrease with increasing their concentration. From unusual low pH of the concentrated MgCl₂ solution, relations between pH and MgCl₂ concentration of sea water, brine and bittern were studied. Neutralization curves of MgCl₂ and MgSO₄ solution were obtained, and pH of the solutions of those salts were determined at various concentration. Effects of Mg(OH)₂, HCl and NaHCO₃ on pH the MgCl₂ soluion were also estimated. Factors on which pH of sea water, brine and bittern depend were partly discussed.

抄録全体を表示

Sodium salt of 1-naphthylamine-8-sulfonic acid (Peri Acid) is sparinglly soluble in cold water while magnesium salt is easily soluble. Sodium ion is then determined with magnesium 1-naphthylamine-8-sulfonate solution. This method was applied for sea water and brine. 10ml. of the reagnt solution, 12% in concentration, was added slowly to a neutralized sample solution containing 40-80 mg. of Na⁺, and the mixture was kept at 10-15° for 30 minutes. The precipitate was then filtered off and washed with 3 portions of 2-3 ml. of saturated alcoholic solution of sodium 1-naphthylamine-8-sulfonate followed by 2 portions of 1 ml. of absolute alcohol. The precipitate was heatresistant and nonhygroscopic. Heating to 105° was suitable for drying the precipitate. Effects of coexistence of cations were examined in the determination of about 70 mg. of Na⁺. K⁺ and NH⁺₄ did not inte-rfere when presented in amounts not exeeding 10 and 60 mg., respectively. Even about 2mg. of Ca⁺⁺ gave the positive error, but 10 mg. of Ca⁺⁺ did not interfere when 300 mg. of Mg-EDTA was added. Analytical procedures for sea water and brine were established Potassium contents were too small to affect the analytical results, and the interference of calsium was prevented by the addition of Mg-EDTA. About 5 hours were needed for total operations, and results obtained were satisfactory.

抄録全体を表示

Nowadays, radioactive wastes are casted into marine against our will, it is very important to inspect the distination of those elements thereafter.
In this paper, the partition coefficients of some sparingly soluble elements (as hydroxides), which might be defined as the relative ratio of an element in pelegic sediment to that in sea-water for iron was standard, was caluculated from the data of average chemical composition of sediments and the amountsoof elements in sea-water. These values were
Al=0.180, Fe=1, Ti=1.73, Mn=0.234, Cr=0.2, V=0.035, Ni=0.011, Co=0.010, Cu=0.019, Zn=0.0024, Pb=0.0055, Mo=0.00024, As=0.0000087, Th=0.15, and U=0.0001, respectively.
From the stand point of the tendencies of accumulation of those elements in sea-water, it is obvious that the element which has low partition coefficient has ordinarily high tendence of acc-umulation in sea-water. Concerning to this fact, several other estimations and the theoretical basis of the calculation were reported and discussed.

抄録全体を表示