Chemistry and Physics. 231 



SCIENTIFIC INTELLIGENCE. 

 I. Chemistry and Physics. 



1. The Recovery of Potash and Other Constituents from Sea- 

 Water Bittern. — Joel H. Hildebrand states that the total pro- 

 duction of potash in this country, calculated on the basis of K 2 0, 

 was about 14,000 tons during the first half of the year 1917, an 

 amount equal to only about 10 per cent of the normal amount 

 used before the war. He states that about 140,000 tons of 

 common salt are produced annually from sea-water in the region 

 of San Francisco Bay, and that if the potash in the mother- 

 liquor or "bittern" from this salt could be saved it would add 

 about 10 per cent to the present production of the country, while 

 a much greater yield might be obtained by utilizing also the bit- 

 terns from other regions on the Pacific Coast. Professor Hilde- 

 brand has presented a very good review of the elaborate scientific 

 study by Van't Hoff and his co-workers of the relationships of 

 the simple and double salts in deposits from ocean waters, in 

 order to make these principles easily accessible for use in solving 

 this problem. He has also worked out from laboratory experi- 

 ments a proposed process, the outline of which is as follows : 



"Evaporate bittern till boiling point becomes about 120°, and 

 density (hot) 1-35. Separate solid and liquid while hot (settling 

 tank and centrifuge). 



A. Solid. NaCl and MgS0 4 .H 2 0. 



Dissolve out NaCl with cold water (containing some 

 MgCL ? ) ; dissolve residue in hot water and cool with 

 ice machine, getting MgS0 4 .7H 2 0. 



B. Liquid. Cool. 



I. Solid carnallite (KMgCl 3 .6H 2 0) 



Extract with minimum amount of cold water 

 leaving. 



1. Solid KC1. 



2. Solution. Evaporate partly. Cool. 



a. Solid carnallite. Add to I. 



o. Solution of MgCl 2 . Add to II. 

 II. Solution, mainly MgCL. Bleach with Cl 2 and 

 remove Br,. Evaporate, cool and recover 

 MgCL.6H 2 0"." 



The process appears to be well planned, and it agrees in some 

 important features with the methods used in the German 

 potash industry. It is a question whether the large amounts 

 of magnesium salts that might be produced would be market- 

 able, and it is suggested that hydrochloric acid and the oxide 



