1822.] Method of analyzing the Ores of Nickel. 4^ 



f. This oxide was treated with muriatic acid, and the solution 

 evaporated to dryness ; the dry mass was redissolved in water, 

 which left a white powder undissolved. This powder was arse- 

 niate of peroxide of iron, which, after heating, weighed 1 part, 

 equivalent to 0*44 part of metalHc arsenic, and to 0-215 of iron^ 

 The quantity of oxide of nickel obtained was, therefore, 14*32 

 parts, equivalent to 11-27 of metalhc nickel. In that which I 

 here estimate as pure nickel, there was a small quantity of lime 

 which became evident when the solution of neutral muriate of 

 nickel was mixed with an excess of subcarbonate of ammonia; 

 but the quantity of carbonate of lime precipitated was too incon^ 

 siderable to be separated and weighed. 



The analysis then gives 



Arsenic, ef 55*50 



Sulphur, a b 12*67 



Nickel,/. 28*17 



lxon,df 3*63 



Earthy matter 0*61 



100-58 



The excess given by this analysis is undoubtedly owing to the 

 hygrometric moisture contained in the sulphuret of arsenic at 

 the time of weighing. This inconvenience would be, however, 

 easily avoided by fusing the sulphuret in vacuo, if at the time of 

 the solution of the ore, the formation of a small quantity of 

 arsenic by the action of the nitric acid upon the arseniuret 

 could be prevented ; this last circumstance renders the method 

 employed in the analysis described quite inapplicable ; for it is. 

 not a question of approximations, but of results, as accurate as^ 

 possible. 



(B.) Analysis by Means of Nitromuriatic Acid. 



The lime found in the preceding analysis made me suspect 

 a mixture of carbonate of lime with the ore. In the following; 

 analyses I have employed an ore of nickel which was powdered 

 and digested in dilute muriatic acid, until all the carbonate of 

 lime was extracted. 



a. Ten parts of the nickel ore dissolved by nitromuriatic acid^ 

 left 0-55 part undissolved; this was sulphur, which burnt with- 

 out residuum. The solution gave 6-5 parts of sulphate of barytes^ 

 equivalent to 0*897, or added to 0*55 14*4 per cent, of sulphur. 



b. The liquid was then deprived of the excess of barytes by 

 means of sulphuric acid. It was afterwards precipitated by 

 caustic potash, added in great excess. The precipitate, welt 

 washed, was re-dissolved in muriatic acid, and the solution 

 was mixed with caustic ammonia, until the oxide of nickel was 

 dissolved. The ammonia left 0*98 part of sub-arseniate of 

 iron. This dissolved in concentrated muriatic acid, without any 

 green appearance, which indicates even very small quantities ai 



