Thornton and Hay den — Separation of Zirconium. 141 



at 110° C. If it be desired to save time, the ignition can be 

 started with the precipitate moist — exercising great care, how- 

 ever, to avoid loss by spattering. With the lid not quite 

 covering the crucible, the volatile matter is cautiously smoked 

 off, the residual carbon burned away, the Meker burner applied 

 for one half hour, and the zirconium oxide weighed. The 

 ignition should be repeated, of course, until a constant weight 

 is obtained. 



In order to determine to what extent the zirconium deriva- 

 tive of nitrosophenylhydroxylamine includes fixed alkalis when 

 salts of the latter are present in the solution, zirconium deter- 

 minations were made in the presence of a large excess of 

 potassium sulphate. The mode of experimentation was the 

 same as that employed in the case of the separation of zirco- 

 nium from aluminum. Table IY shows the results of two 

 experiments. 









Table IV. 











The 



Separation of Zirconium 



from Potassium. 







Zr0 2 



K 2 



Zr0 2 





H 2 S0 4 



Volume 



No. 



taken 



taken 



found 



Error 



(1:1) 



of soln. 





grm. 



grm. 



grm. 



grm. 



grm. 



cm 3 



11. 



0-1088 



2-7027 



0-1097 



+ 0-0009 



40 



400 



12. 



0-1089 



2-7027 



0-1096 



+ 0-0007 



40 



400 



It will be observed that the gain of weight undergone by the 

 zirconium is not very large, and when one considers that the 

 amount of potassium present (calculated as oxide) is nearly 

 twenty-five times as great as the zirconium (also reckoned as 

 oxide), the tendency of the precipitate to carry down alkalis 

 need not be regarded as serious. 



It remains now only to call attention to the chief points of 

 merit possessed by this method of analysis. The precipitation 

 of zirconium by the " cupferron " reagent is quantitative. 

 From solutions strongly acidified with sulphuric acid, a clean 

 separation of zirconium from aluminum can be effected. Tar- 

 taric acid does not interfere with the precipitation so that the 

 acidified filtrate from the ferrous sulphide is in fit condition 

 for the separation of zirconium from aluminum — a fact which 

 obviates the necessity for oxidizing the organic oxyacid. The 

 precipitate comes down immediately in flocculent and readily 

 filterable condition, is little prone to include alkalis, and after 

 drying can be converted into zirconium oxide of a high degree 

 of purity. The manipulation is extremely simple and the 

 sources of error are few. 



May 26, 1914. 



