396 F. S. Havens — Separation of Nickel and 



Art. XXXYIII. — On the Separation of Nickel and Cobalt 

 by Hydrochloric Acid ; by Franke Stuart Havens. 



[Contributions from the Kent Chemical Laboratory of Yale University.— LXXV.] 



A quantitative separation of nickel and cobalt by a 

 process analogous to that published from this laboratory for 

 the separation of aluminum and iron* has been put for- 

 ward in a recent paper by E. Pinerua.f The process may 

 be described briefly as follows : The hydrous chlorides of 

 nickel and cobalt (0-3-04 gms.) are dissolved in a little water 

 and to the solution are added 10 to 12 cm3 of aqueous hydrochloric 

 acid and 10 cm3 of ether, and the whole, contained in a little 

 beaker surrounded with water and ice, is saturated with gaseous 

 hydrochloric acid. The cobalt, which remains in solution, is 

 decanted off and the yellow insoluble nickel chloride washed 

 with a previously prepared solution of ether saturated with 

 hydrochloric acid gas at a low temperature. The nickel is 

 determined by known methods, preferably as the sulphate. 

 The author claims very precise results for the process, but 

 gives no experimental proof of his work. Previous to the 

 appearance of this paper my experiments upon the solubility 

 of nickel chloride in an ether-hydrochloric acid solution, such 

 as used in our process for the separation of aluminum and iron, 

 which is practically the same in proportions as that used by 

 Pinerua to effect precipitation, had shown that, while nickel 

 chloride is somewhat insoluble in such a mixture, the degree of 

 insolubility is not sufficient for a quantitative separation. Since 

 the appearance of Pinerua's work I have been over the ground 

 again and have reached the same conclusions as before, as 

 shown in the following experiments. 



When a solution of 0*2 gm. of nickel chloride (free from 

 iron and cobalt) in 7 cm3 of aqueous hydrochloric acid, was 

 saturated with hydrochloric acid gas at a temperature of —2° 

 C. (obtained by immersing the container in a mixture of ice 

 and salt) no precipitation resulted. When, however an equal 

 volume of ether was added and the whole was again saturated 

 with hydrochloric acid gas a yellow precipitate formed, while 

 the supernatent liquid still remained of a deep green color. 

 The solution was filtered quickly through asbestos in a filter 

 crucible, and the clear filtrate after evaporation with sulphuric 

 acid was electrolyzed. The metallic deposit of 0*0020 gm. 

 proved to be pure nickel ; for when dissolved in nitric acid it 

 gave no test for iron with potassium sulphocyanide or ferro- 



*Gooch and Havens, this Journal, IV, ii, 416. 

 f Gaz. Chim. Ital., xxvii, 56. 



