Section III., 1915 193] Trans. R.S.C. 



On the Separation and Determination of Nickel and Cobalt. 



By T. L. Walker, University of Toronto. 



Presented by Prof. W. H. Ellis, F. R.S.C. 



(Read May Meeting, 1915). 

 I. THE RED LEAD SEPARATION. 



In the analysis of ores and metallurgical products containing 

 nickel, the separation of this metal from iron has always constituted 

 one of the most tedious operations. In general the iron has been 

 separated by means of sodium acetate but much experience is necessary 

 to secure a quick filtering precipitate which can be easily washed. 

 In 1890 when engaged as chemist with Messrs. H. H. Vivian & Co., 

 at the Murray Mine, Sudbury, Ontario, I was advised by Alfred 

 Merry, one of the directors of the company to separate the iron by 

 means of red lead — PbsOé. In his opinion this method should be 

 employed only for such analyses as did not require the highest degree 

 of accuracy. It had been long employed in the laboratories of this 

 company in Swansea and was communicated to me as a secret method 

 devised by Mr. Merry himself and used in their works alone. Some 

 years later at my request Mr. Merry gave me permission to make 

 this method generally known. 



So far as I am aware this method of separating iron from nickel 

 and cobalt has never been published and it appeared to me desirable 

 to determine its accuracy and the best conditions for operation with 

 a view to giving it wider publicity. The results incorporated in this 

 paper have been obtained from a series of experiments carried on 

 during the past winter. 



To a hot solution containing iron, nickel, cobalt, copper and lead 

 as chlorides, add a few drops of hydrogen peroxide to change all the 

 iron to the ferric condition. Nearly neutralise by carefully adding 

 sodic carbonate and then gradually red lead while boiling in a flask. 

 It is necessary to continuously agitate the flask. Chlorine is evolved 

 with the precipitation of lead peroxide and ferric hydroxide. The 

 red lead should be added to excess as shewn by the distinct red colour 

 of the heavy precipitate. The separation of the iron is complete 

 in a few minutes. The precipitate is heavy and granular. Filter and 

 wash by décantation and finally bring the major part on to the filter, 

 washing with hot water. From the filtrate the lead and other metals 



