2 Taylor, Method of Separating Cobalt and Nickel. 



calcium) in presence of free chlorine or bromine, and that 

 nickel is not so precipitated. The following equation 

 practically represents what takes place in the case of 

 cobalt : — 



2C0CI2 + sBaCOs + Clo = C02O, + 3BaClo + 3CO2. 

 It is very probable, however, that the cobalt is converted 

 from a cobaltous to a cobaltic salt before it is precipitated 

 by the carbonate. 



According to his original description of the process. 

 Rose passed a stream of chlorine through a somewhat 

 dilute solution of the chlorides of the two metals, contain- 

 ing a considerable excess of hydrochloric acid, for several 

 hours. He then added excess of barium carbonate and 

 allowed to stand, with frequent agitation, for from 12 to 

 18 hours. By the end of that time the cobalt was all 

 converted into sesquioxide and the nickel remained in 

 solution and could be filtered off. In his remarks on 

 Rose's method (referred to above) Henry suggested the 

 use of bromine instead of chlorine. In a subsequent 

 letter {Chemical Gazette, 1855, p. 237), Henry stated that he 

 had, by keeping the temperature at 120*^ F., succeeded in 

 reducing the time required to a few hours. He considered 

 that the results, however, were not so good as those 

 obtained by Liebig's method of separation by means of 

 potassium cyanide. 



Induced principally by a desire to find a better method 

 than those usually employed for the qualitative separa- 

 tion and detection of nickel in presence of cobalt, I have 

 recently made some experiments on the action of barium 

 and calcium carbonate on solutions of the two metals, in 

 presence of chlorine and bromine. As the result of these 

 experiments, I find that the method of Rose can be 

 considerably shortened, with the result also of making it 

 much more accurate. 



