1(14- Browning and Blumenthal — Decomposition of the 



Art. XVIII. — On the Decomposition of the Cerium Earth 

 Double Sulphates with the Alkali Sulphates by Fusion 

 with Charcoal; by Philip E. Browning and Philip L. 

 Blumenthal. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — ccxxii.] 



Among the best known and chief sources of the cerium earths 

 are their insoluble double sulphates with the alkali sulphates 

 obtained as a by-product in the process for the separation of 

 these earths from the earths of the yttrium group. The prob- 

 lem which has to do with the conversion of these insoluble 

 sulphates into soluble salts of the cerium earths is therefore 

 an important one. The procedure in general use brings about 

 this result by treating the double sulphate with sodium, or 

 potassium hydroxide until the cerium earths are converted to 

 the hydroxides when the alkali sulphates may be removed by 

 washing. The hydroxides are then dissolved in any conven- 

 ient acid. This method is at best tedious both in the prepara- 

 tion of hydroxides and the removal by washing of the alkali 

 sulphates. The double sulphates are sometimes digested with 

 hydrochloric acid and then treated with water, but here also 

 the process is slow in yielding soluble cerium earth material. 

 Or, the double sulphates are treated with large volumes of 

 water, frequently stirred, a method even more time consuming 

 than the others. 



The work to be described was undertaken to test the appli- 

 cation of the reduction by carbon to this problem. This 

 method has been applied to the preparation of soluble barium 

 and strontium salts from barite and celestite* and, as we dis- 

 covered late in our work, is mentioned in connection with some 

 work on cerium over fifty years ago.f As this early work 

 gave no details or numerical results and contained some state- 

 ments which our work would hardly bear out we have thought 

 best to give our results. 



The material which we used. was a crude double sulphate, a 

 technical by-product carrying appreciable amounts of calcium 

 and iron salts together with some sand. 



In order to obtain a standard to which to refer results, five 

 portions of one gram each were dissolved in from 300— i00 cm3 of 

 water by frequent stirring for several hours and the solutions 

 were precipitated in faint acidity by oxalic acid. The oxalate 

 was ignited and the oxide weighed, yielding - 3897 grm. 



* Introduction to Chemical Preparations, Erdmann-Dunlap, first edition, 

 pages 27 and 30. 



fBerzelius and Hisinger (1804), Ann. Chim. pbys., L, 259 ; Beringer (1842), 

 Liebig Ann., xlii, 135 ; Schmidt (1852), Liebig Ann., lxxxiii, 329. 



