On the Separation of Nickel and Cobalt from Manganese. 197 



sions : — 1st, that solar light does not seem to exei'cise any sensible 

 influence on the process of combustion ; and 2ndly, that varia- 

 tions in the densiiy of the air do exert a striking effect in retard- 

 ing or accelerating the rapidity of the process, the rate of burn- 

 ing augmenting with every increment of density, and vice versa ; 

 but the exact ratio between them remains to be determined. 

 Columbia, S.C, June 185/. 



XXI, On the Separation of Nickel and Cobalt from Manganese. 

 By T. H. Henry, Esq., F.R.S.* 



THE methods given by the best authorities for the separation 

 of nickel and cobalt from manganese are either inconve- 

 nient or inaccurate. The only method which affords exact 

 results is that of Ebelmen, in which the sulphides formed at a 

 high temperature are acted upon by dilute hydrochloric acid; 

 but it is both tedious and unpleasant to pass sulphuretted hy- 

 drogen over the oxides contained in a porcelain tray in a porce- 

 lain tube at a red heat; and the modification suggested by 

 Wohler, of converting the oxides into sulphides by fusing them 

 with sulphur and carbonate of soda, still furnishes the sulphide 

 of nickel in such « state that it is slightly acted upon by very 

 dilute hydrochloric acid. 



I have obtained very accurate results by a process differing 

 altogether from those described, but as simple as any. 



When chloride of ammonium and ammonia are added to a 

 warm solution of sulphate of manganese or chloride of manga- 

 nese, and afterwards phosphoric acid till the precipitation ceases, 

 the whole of the manganese is precipitated ; and after filtration 

 no precipitate or even cloudiness is produced by the addition of 

 sulphide of ammonium to the solution. The salt formed is, 

 according to Otto, NH^O 2MnO, P0H2H0, and after igni- 

 tion 2MnO + PO'^. When a solution of chloride or sulphate of 

 nickel is treated in a similar manner, no precipitate occurs, even 

 on standing a few days in a vessel lightly covered, when suffi- 

 cient chloride of ammonium and free amnionia are present. 



The following example will show the mode by which I operate. 



12"6 grs. of pure sulphate of manganese, MnO S0^ + 4H0, 

 were gently ignited, and weighed 8"73 grs. = 4*1 1 MnO. 6 grs. 

 of oxide of nickel, containing a trace of silica, were ignited and 

 weighed then 5'63 grs.; these were dissolved together in hydro- 

 chloric acid and water, and the solution diluted ; it was made 

 acid with hydrochloric acid, phosphoric acid was added, and the 

 whole heated until nearly boiling : when anmionia was added in 



* Communicated by the .\uttior. 



