The drying characteristics of common salt in the fluidized bed was studied using washed salt and flake salt in the single-stage test apparatus.
(1) With the increase of air velocity in column, air temperature and mean resident time of material, the water content of product became low.
(2) The heat transfer capacity coefficients on the basis of weight of material is expressed by the following experimental formula.
ha′H:=0.001Δp0.75G_T^1.25
h: film heat transfer coefficient (kcal/m²hr°C), a′: effective heat transfer area per unit weight of material (m²/kg), H: weight of the resident material per unit area (kg/m²), Δp: pressure drop in fluidized bed (kg/m²), G_T: quantity of air per unit area
(3) The heat efficiency in this type dryer was found to be equal to that of pneumatic conveying dryer.
(4) Size reduction of crystals was a little in case of flake salt. In the washed salt, the crystals was apt to agglomerate and this tendency was remarkable with the increase of air temperature or decrease of air velocity.
(5) The weight of resident material in fluidized bed was found to be equal to its pressure drop, and the relation between its material weight and height of over-flow outlet may be expressed by the following experimental formula.
H=398lu^-0.79
l: height of over-flow out let (m), u: air velocity (m/sec)
(6) From the observation of fluidized bed, the suitable air velocity was about 0.75m/sec.

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Small-scaled experiments were conducted regarding the use of a V-type mixer for mixing dry-salt with 0.1% of anti-caking agent, and as a result we selected such an operating condition as that which makes the coefficient of variation of the adding agent approximately 4%.

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Studies were made on the measuring of the dissolving rate of salt by the fall of the temperature indicated when salt was dissolved in an agitator.
This method is very simple and can easilyhe used. The results obtained by this method proved to be fairly satisfactory. Experiments in this report made the following points clear:
1. As is already well known, coeficient of mass transfer does not have any relationship with the size of grain, but it is not constant and shows an increase as the dissolving rate increases.
2. The number ofgrains, even if they are screened, is not necessarilyequivalent to that of those grains added during the process of dissolution, but when it exceeds a certain degree of dissolution, it gradually decreases until it finally diminishes.

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The quantitative analysis as to Na₂SO₄ contained in refined salt has so far been carried out by an indirect method, but in our study we made an attempt to determine the quantity of Na₂SO₄ by using Ba-EDTA.
The sample solution (20g→250ml) 25ml of refined salt prepared was mixed with approximately 15ml of water and 10ml of M/100 Ba-EDTA. After the mixed solution was heated, it was given M/100 HCI 4ml in the form of drops until it precitated at the stage of the pH of 2.0-3.0. The solution was kept stilly for about 15 minutes and cooled, and then it was given 20ml of CH₃OH and cooled for about 5 minutes. The solution containing the precipitate was titrated by M/100 MgCl₂ solution using EBT as an indicator in pH 10. In this case, the end point was easily measured by adding the already-known MgCl₂ solution and by titrating M/100 EDTA solution.
This method can also be applied to the direct quantitative analysis of MgCl₂ contained incommon salt.

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As mentioned in our previous report, we found in our former experi-ments that when sea water is concentrared by electrodialysis with heterogeneous ion exchange membranes, the amount of brine to be obtained greatly influences the retsult of the concentration. This time, therefore, we made a study as to the influence by keeping the current density constant, and obtained the following results:
1. When the amount of brine to be obtained is increased by the increase of water head difference between the both concentrated and desalted chambers, the amount of salt to be obtained shows an increase, but the concentration of brine becomes lower.
2. The decrease in the amount of brine results in the decrease of the current efficiency, and as a consequence the consumption of electricity increases.
3. When the amount of brine is increased, the voltage of cell slightly increases.

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The basic studies conducted on the utilizing of wind tunnels for investigating the character and capacity of Shijoka have already been reported by M. Hashizume, Y. Ikeda, etc. in Scientific Papers of Hofu Salt Experiment Station 10,111 (1958), 12, 76-79, 98-106 (1959).
In this report, we try to investigate, as application experiments of the results of our previous studies, the new vertical system concentrator which utilizes the high efficiency of Shijoka, by making use of the energy of natural wind.
In our experiment, guide plates were placed on the both sides of the Shijoka in order to regulate the direction of wind. Then the utilization of wind was investigated in the case those guide plateswere used for the Shijoka. In these experiments, we made a study as to how to rationalize the arrangement of Shijokas.

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As the result of our experiments conducted in order to measure the distribution of vapor pressure on the surface of evaporating water and on that of the shijo of the both model and actual shijokas, and to measure the thickness of the boundary layer of the evaporating water, the following were obtained;
(1) The following experimental formula can be established in connection with the thickness of the boundary layer (S) and the diameter of the evaporating water surface (d);
δ/d=2.06 (Pγ.Gγ) ^-0.22
Pγ.=ν/D
Gγ.=g.d³/ν²|ρ′/ρ_o-1|
ν: kinematic coef. of velocity of the air, D: coef. of vapor diffusion, g: gravity acceleration, ρ′, ρ_o: vapor density in the air of water surface and outside
(2) The thickness of the boundary layer formed on the surface of the shilo is approximately 4-6mm no matter how the conditions may change.

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A. Experiments were conducted in order to measure the diameter of the water drops falling down from the inside of the shijoka, and as a result the following relationship was made clear:
1. Diameter of water drops
The following experimental formula was obtained in connection with the relationship between the radius (r) of the water drops and that (R₁ and R₂) of the trace of the water drops marked on the filterpaper of eosin and the glass plate coated with magnesium oxide:
(1) Eosin paper
r=399.80+0.121R₁-337.36l^-0.0005R₁
(2) Magnesium oxide plate
r=-1.70+0.68R₂
2. Form of water drops
The following experimental formula was obtained in connection with the relationship between the radius (r) and the transforming rate of the water drops (b/a: b: height of the drops, a: horizontal maximum length of the drops):
b/a=1.015-0.017r-0.013r²
B. The water drops with the radius which is less than 0.02cm.occupy 50 percent of all the drops falling down from the Shijoke.

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