Bulletin of the Society of Sea Water Science, Japan
Online ISSN : 2185-9213
Print ISSN : 0369-4550
ISSN-L : 0369-4550
Volume 26 , Issue 6
Showing 1-6 articles out of 6 articles from the selected issue
  • Yukio NAGAOKA, Shiro AIDA
    1973 Volume 26 Issue 6 Pages 305-310
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
    In order to study effects of corrosion prevention by deaeration upon those materials which are used for salt-making apparatus, experiments were carried out under static condition in sea water, brine and mother liquid at room temperature for 144 hours with mild steel, copper and stainless steel, and under dynamic condition of the flow rate of 1, 2, 3.5 m/sec in saturated brine and 25-30% slurry of salts at 40°C for 240 hours with copper, aluminium brass and cupro-nickel. Results obtained were as follows.
    1. In the static test, the corrosion rate of mild steel showed a decrease in proportion to the increase of concentration of dissolved oxygen, notwithstanding the kind of liquids. The corrosion rate of copper declined in line with the increase of the concentration of dissolved oxygen, but the limited concentration of dissolved oxygen showed a tendency of controlling corrosion. The corrosion rate of stainless steel proved to be low regardless of the concentration of dissolved oxygen.
    2. In the dynamic test of saturated brine, the corrosion rate of each material showed a decline with an increase in the concentration of dissolved oxygen. The corrosion prevention rate by deaeration of copper, aluminium brass and cupro-nickel turned out to be 90, 40, 20%, respectively.
    3. In the dynamic test of 25-30% slurry, the corrosion rate of materials except copper at atmosphere showed a rise of 8-9 times, and the effect of crrosion prevention was very low. This was considered to be attributable to the fact that erosion was promoted by the abrasive action of flowing salt crystals.
    4. Ferrous sulfate was found to have corrosion controlling effects on copper and copper alloys.
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  • Kunio SUGINO, Kenzaburo OBATA, Totaro GOTO
    1973 Volume 26 Issue 6 Pages 311-315
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
    An automatic analyzer for total carbon dioxide in decarbonated sea water was developed. The apparatus is based on the fact that electric conductivity of a potassium hydroxide aqueous solution changes by absorption of carbon dioxide discharged from the sample sea water.
    The analyzer performs intermittent derminations at a half-hour cycle. Acid solution is added to a sample solution to lower the pH below 4, and the liberated carbon dioxide gas is led to the absorber, potassium hydroxide solution with nitrogen gas. Changes in electric conductivity of the absorber were proportional to the total carbon dioxide concentration of the sample.
    Reliable determinations could be performed with a 200ml sample of 35% sodium chloride solution at room temperature under the following conditions: 300ml/min flow rate of nitrogen gas, 0.005N potassium hydroxide solution, less than 40 ppm total carbon dioxide in sample.
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  • Norio TAKEUCHI, Totaro GOTO, Seiichi ISHIZAKA
    1973 Volume 26 Issue 6 Pages 316-322
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
    The crystallization rates of NaOHH·3.5H2O from a 39 wt.% sodium hydroxide aqueous solution were measured under various conditions. These serve to obtain some fundamental information on a process in which potassium is concentrated in the mother liquor by separation of crystal NaOHH·3.5H2O from a potassium-containing sodium hydroxide solution. A 39 wt.% sodium hydroxide solution was cooled to various temperatures, and then the crystallization was caused by introducing a very small crystal of NaOHH·3.5H2O as seed into the solution. The initial supercooling degree ranged from 2.45°C to 5.35°C. Some relationships such as crystallization rate, supercooling degree, amount of deposited crystal versus time were obtained.
    The results showed that:
    1. The crystallization rate increased in the early crystallization period, but decreased constantly after the maximum value.
    The maximum enlarged with an increase in the initial supercooling degree.
    2. A power of supercooling degree, n, in the equation expressing crystallization rate can be obtained by n=-(2/3) {ΔTmax. Vmax./Wvmax.(dΔT/dt) vmax.}
    3. When the crystallization rate of NaOH·3.5H2O was not influenced by newly formed crystal nuclei, the rate made a linear change to the supercooling degree.
    4. A supercooling degree, under which the amount of newly formed crystal nuclei was too little to affect the crystallization rate, was found to exist, and paralleled to about 60% of the initial supercooling degree.
    5. The number of formed crystal particles increased exponentially with an enlargement of the supercooling degree, and showed a increase of 2.6 times per one degree centigrade of the initial supercooling degree.
    6. The crystallization rate of NaOH·3.5H2O from a 39 wt.% sodium hydroxide aqueous solution was expressed by the following equation under the negligible formation of the crystal nuclei.
    V= {γs/ (ρ·γv) 2/3} ·K·W2/3.N1/3·ΔT
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  • Tsutomu MASUZAWA, Masami KAHO
    1973 Volume 26 Issue 6 Pages 323-329
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
    In order to study the vertical and horizontal distribution of the caking strength of refined salt packed in a 25 kg paper bag, a piling test was carried out with the salt piled up in 24 layers on wooden pallets and with 6 bags in one block, for three months.
    1. In the early stage of piling, those paper bags located in the middle part between the pallets and in the lower part of the layers were found unstable, but they became stable gradually as time passed.
    2. The caking strength showed a linear increase in proportion to the number of layers.
    3. The vertical distribution of caking strength was found larger in the same layer (A, B, C and D).
    4. The distribution of caking strength in one bag was large, and the highest value of caking strength was always shown in the central part of the bag.
    5. Under the piling condition where the absorption and drying of moisture occurred, no relation was found between the caking strength and the water content.
    6. A representative value of the caking strength was chosen from the central part of the bag when the highest value of caking strength was required, while it was chosen at random from the classified layer of the bag when a mean value was required.
    7. The vertical caking strength was greater than the horizontal one by 1-3 times in the same position of the bag. This was attributable to the horizontally moving action of salt particles by incumbent pressure in the bag.
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  • Yoshihiro NAKASHIMA, Nobuaki NAKAZAWA, Koichi TAWARA
    1973 Volume 26 Issue 6 Pages 330-334
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
    A small notch meter was specially designed for measurement of minor flow rates and was put into experimental use. As the result of this experimental use, the flow meter was found to have a comparatively high accuracy in the measurement of such an extremely minor flow rate as 200 kg/hr. The equation of the flow meter is as follows:
    W=2/3·√2g·ρ·B (1.349B+0.084) ·h (-2.680B+2.493) 0.05<B<0.25 (cm) 0.0<h<10.0 (cm)
    B is width of the notch, cm;
    g is acceleration of gravity, cm/sec2;
    h is height of liquid of the notch, cm;
    W is flow rate, g/sec.
    This flow meter proved to be usable for measuring dynamic hold up of a vacuum packing tower
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  • E.R. ROBERTS, David D. KAYS
    1973 Volume 26 Issue 6 Pages 335-347
    Published: 1973
    Released: February 19, 2013
    JOURNALS FREE ACCESS
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