ir. A. Turner — /Separation of Vanadium. 109 



Akt. XL — The Separation of Vanadium from Phosphoric 

 and Arsenic Acids and from Uranium ; by W. A. Turner. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — cclxxix.] 



In a previous paper* the determination of vanadium when 

 present in the form of a soluble vanadate has been described. 

 It seemed desirable to make use of this determination for 

 separation of vanadium from some of the common impurities 

 with which it is associated in nature. To this end separations 

 from phosphoric and arsenic acids and from uranium have been 

 attempted and. the following pages are a record of these ex- 

 periments. 



In the separations from phosphoric and arsenic acids the pro- 

 cedure was exactly the same as in the simple determination of 

 vanadium with the exception that the precipitates required a 

 more thorough washing. This procedure is briefly as follows : 



Portions of about 25 cm 3 of the meta vanadate solution, 

 accurately weighed, were diluted to about 150-200 cm 3 . The 

 amount of phosphate or arsenate indicated was added and 

 enough sulphuric acid to make about one per cent of the 

 volume. Cupferron (the ammonium salt of nitrosophenyl- 

 hydroxylamine) was then added in six per cent solution with 

 stirring until a slight excess was present as shown by the ap- 

 pearance of a white precipitate of nitrosophenylhydroxylamine 

 (formed when cupferron comes in contact with an acid solution). 

 Two or three cubic centimeters in excess are added and the 

 precipitate is filtered without delay and washed with a one 

 per cent solution of sulphuric acid containing a little cupferron. 

 The precipitate after being allowed to drain for a time on the 

 filter is transferred to a platinum crucible, dried, ignited and 

 weighed as vanadium pentoxide. 



The vanadium used was a solution of ammonium metavana- 

 date in distilled water which when standardized by the cup- 

 ferron method gave the following result : 



25 grms. NH 4 V0 3 sol. o 0-1003 grm. V 2 6 . 



As sources of phosphoric and arsenic acids disodium hydro- 

 gen phosphate and disodium hydrogen arsenate were used. 

 The precipitates were washed fifteen times. 



The following table shows how successfully these separations 

 can be accomplished : 



Grms. NH 4 VO s 

 sol. taken 





Grms. VjOs 

 found 



Grms. 

 25 grms.' 



V2O5 per 

 NH4VO3S0I. 



A 



Impurity added 



Found 





Taken 



25-0940 



1 - 5 grms. 













Na,HP0 4 .l2H s O 



0-1008 



0-1004 





0-1003 



25-0973 



u 



0-1006 



0-1002 





0-1003 



95-0244 



1*5 £i'ins. 













Na 2 HAs0 4 .12H 2 



0-1006 



0-1005 





0-1003 



25-0841 



* This Journal (4), 



0-1007 

 xli, 339, 1916. 



0-1004 





0-1003 



