Crystal gypsum, magnesia and magnesium chloride were obtained as byproducts from salt making plants, and they were studied to be used as valuable and special gypsum-magnesia cement. Magnesia cement (xMgO·MgCl₂·yH₂O) is unstable owing to its weak water proofness and weak hardened strength changeable by the mixing proportion of magnesia and magnesium chloride solution, the concentration of magnesium chloride solution, the calcining temperature of light magnesia, etc.
These defects of magnesia cement were excluded by adding some parts of (1) calcined gypsum (CaSO_4·1/2H₂O) to light magnesia to make speciai gypsummagnesia cement,(2) calcined dolomite (CaO+MgO) or dolomite plaster (Ca(OH)₂+Mg(OH)₂) to make special dolomite-magnesia cement, or (3) both of light magnesia and calcined dolomite to make special gypsum-dolomitemagnesia cement. These three kinds of special magnesia cements were studied by systematically comparing with common simple magnesia cement, and the results of the first special gypsum-magnesia cement and the seeond special dolomite-magnesia cement were especially reported in the present report.

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A method of graphical calculation of the quantitative relations in the preparation of schoenite or leonite by the double decomposition or artificial carnallite with the “earthy sulphate”, was devised. By using the euilibrium diagram for the five components system of oceanic salts, i. e., Na⁺-K⁺-Mg⁺⁺-Cl^--SO₄^-H²O system saturated with NaCl, the optimum proportion of carnallite, eathy sulphate and water in the initial mixture for the double decomposition, yield of potassium, amount of schoenite or leonite obtainable, and amount of NaCl acompanying it, were computed at 0°, 10°, 15°, 25°, 40° and 55°C. By this means, the followings weie found:(1) At a ternperature, the best yield of potassium was gain, when the ratio of MgCl₂/KCl in the mothor liquor is maximum.(2) It is desirable to use the “earthy sulphate” containing the less NaCl and the more KCl, such as obtained at lower tempetature under high vacum.(3) At 0°-20°C, schoenite is obtainable, and 20°-55°C leonite is obtained,(4) The best condition to get schoenite was found at about 10°C, and leonite at 30°-40°C.(5) As the best result, yield of potassium reached. to 81% and the purity or the kalimagnesia to 88% containing 12% NaCl.

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We found that the addition of “Krilium” (Formulation No.6 of Monsante Chemical Co.) to the brine super-saturated with CaSO₄ makes sustaining of the super-saturation more effective than well knowm “Calgon”, and obtained good results at the temperature 50-70°C.

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Using Shijyoka, the floor beading area of which was 255m (15mX17m), the height of which was 5 meter, and the step hanging bamboo branches of which was 5, we performed the following examinations.
1. Distanco and amount of drops of sea water or brine scattered in the wind while one was poured.
2. Effect of making evaporation accelerated, when the original liquid was poured after making preheated.
3. Result of brine obtuined in the state of continuous concentration.

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1. Sea water free from Ca being its PH about 5 was feeded to tube boiler, 20kg/cm² press, during 19days extracting continuosly concentrated brine (Ca. 17°Bé). Acidity of feed water Were PH 5 at feeding PH 7 in preheater and PH 8 over of brine. At this condition, no scale deposits and no covasion decoquised in the boiler no coloured the brine. In the case of higher PH, deposited Mg (OH)₂ and lower PH. were covrobed the boiler.
2. Sea water free from Mg & Ca being its PH about 7 was feeded to tube boiler, 20-30kg/cm² press,(Takuma or Galbe) during long period extracting continuously conc. brine (about 17°Bé). Its PH indicates over 8 in preheater and over 11 of brine. No scale was deposited and no corrosion was recognised in the boiler.
3. Heat efficiency of the boiler between the purified sea water feeding and water feeding was no difference being a little higher the preceding.
4. No chloride was detected in the steam from boiler by neears of Ag No.3. and no chlorode was deposited in the superheater.

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The following results were obtained.
1) Pressure drop of a designed cyclone was about 4-fold to inlet velocity head, for details, it was given by the function of μ/ρ of fluids.
2) In this case, it proves that Ikemoris theoritical formula is applied for the minimum size of separated solid particles.
3) In a certain condition of the over flow pipe, it proves to form the core of a by the spiral current through the over flow pipe.

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Following the first report, the seasonal variation on the chlor content in sea water in cannals at the salt fields was investigated.

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Vol. 7 (1953) No. 5 p. 191-193
修正箇所：本文

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Vol. 7 No. 5 p. 206-210

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Vol. 7 (1953) No. 5 p. 225-226

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