Experiments on the industrial application of drop-wise condensation by cetyl-mercaptan as promoter were performed employing thermocompression and multiple effect types of salt manufacturing apparatus.
The results showed that the over-all coefficient of heat transfer was increased by about 10% in the thermocompression type and 5% in the multiple effect type apparatus respectively compared with ordinary conditions.
But these results were a little inferior to those obtained in the course of our basic experiment already reported.
The main reason was presumed to be the increase of heat transfer resistance and the hindrance of absorption of the promoter to the surface of copper face by corrosion products such as cupric oxide, which adhered to the surface of heating tubes in these apparatus.

View full abstract

Formation of (K, NH⁴) ₂·2MgSO₄ by the addition of ammonium salts to bittern at about 100°C was utilized as a new method for the separation of potassium from bittern.
Studies were made to find out the conditions where by,(1) to separate the double salt with a good yield,(2) to precipitate Mit and potassium in filtrate as a mixed crystal of ammonium and potassium shoenites by the addition of MgSO₄·7H₂O to filtrate.
The results showed that more than 80% of potassium and 70% of NH₄ added were easily separa ted in total.
It was supposed that such a high yield of potassium was due to the resemblance in characters between potassium and NH₄ radical, and the replacement of the former by the latter.

View full abstract

Experiments were conducted on electrolytic concentration of sea water with porous heterogeneous ion exchange membranes, and the following results were obtained.
1. The consumption of electric power for producing the concentrated brine equivalent to one ton of salt is influenced by the current density, but it is also greatly influenced by the amount of brine to be produced.
2. The efficiency of the electric current differs according to the amount of brine to be produced. Accordingly, when the amount of brine is increased, the efficiency becomes higher.
3. Brine decreases its specific density as the amount is increased.
4. The above results are considered to be attributable to the porosity of the ion exchange membranes.

View full abstract