Dichlorodifluoromethane (R-12), monochlorodifluoromethane (R-22), and dichloromonofluoromethane (R-21) were all able to form hydrate compounds under profitable conditions. As a part of basic experiments for the hydrate process, we measured their solubilities for water and NaCl solutions, taking pressures, temperatures, and salt concentrations as experimental factors. The results obtained from those experiments were as follows.
1) At 20°C, 1 atm., solubilities for pure water were R-12:0.03%, R-21:1.2%, and R-22:0.38%, and increased linearly with pressures.
2) On the salt concentrations of solutions N, we obtained the following equation. KN=log S/S_o(K: const., S, S_o: solubilities for NaCl solutions and pure water, respectively)
3) The thermal coefficient of solubilities was negative, and when pressures and salt concentrations were kept constant, the following relations were recognized. ΔH/R=-dlog S/d (1/T)
By these relations, heats of dissolution ΔH were calculated (R-12:5.9, R-21:10.1, R-22:7.3kcal/g mol), and moreover with those values, it was possible to correct the heats of hydrate formation.
4) Activity coefficients γ amounted to several thousands for R-12 and several hundreds for R-21. When only salt concentrations were kept constant, γ decreased with the increases of solubilities and could be drawn on a curved line.

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A dry magnetic separator has been applied to remove iron particles contaminated in common salt. But the dry separator is not used for “Common Grade Salt” containing more than 2% of moisture. In this experiment, a comparison on the removal was made among three types of wet magnetic separators in the sludge of salt, Filter type, Plate type and Drum type.
The results were;
1) The Filter Type Separator was the best removing 99.8% and 96% of added iron particles (3mg/kg raw dry salt) in the sludge feed 1.8 tons per hour and 13 tons per hour, respectively.
2) The results of Plate type and Drum type were 60-70% and 70-80% in the sludge feed less than 5 tons per hour.
3) The Filter type separator removed the contaminated iron particles to the quality of “Refine Salt”(0.04mg/iron particleskg Refine Salt)
4) As shown in 1)-3), the wet magnetic separator is applicable to the salt manufacturing factory for the removal of iron particles in the sludge of salt.

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A comparison was made on the effects of sodium chloride and calcium chloride in connection with the melting and break-up of ice on road surface with salt, and the following results were obtained:
1. The effectiveness of calcium chloride was rapid, but that of sodium chloride was slow to the melting of ice.
2. Calcium chloride was higher in the melting effect but was weaker in its penetration into ice at the early stage as compared with sodium chloride, while the total ice break-up with sodium chloride was greater than that with calcium chloride.
3. When salt was applied to ice, the distribution of linear increasing temperature was obtained with sodium chloride and the exponential one with other salts such as MgCl₂and CaCl₂.

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Cellulose phosphate as cation-exchanger was prepared by the following method; 25g of urea was dissolved to 18.2g of 75% phosphoric acid, and this solution was mixed with 5g of cellulose (paper pulp) uniformly. The mixture was held at 170°C for 1hr., washed with water and dried at 90°C.
The product is a weak yellow fibrous material containing 10-11% phosphorous (P) and has the value of about 4 meq (Fe³⁺)/g as the maximum ion exchange capacity.

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[in Japanese]

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