Vanadiferous Minerals in Western Colorado. 137 



Again when the vanadic acid is extracted from the residue by 

 ammonia, as prescribed by Friedel and Cumenge, a little of the 

 other constituents of the residue accompany the vanadium into 

 solution. 



If the combination of the two methods is used, it is better 

 after removal of the vanadium by distillation to further treat 

 the two residues separately at first instead of to unite them at 

 once. Full details of this treatment are unnecessary and 

 would unduly extend this paper. Suffice it to say that from 

 the uranium portion the little iron and aluminum present are 

 separated by ammonium sulphide and carbonate, and after 

 removal of the latter, and acidification, the uranium can be 

 thrown down by ammonium sulphide, and then by at least two 

 precipitations by ammonia, or far better, by precipitating the 

 neutral hydrochloric solution by freshly precipitated and 

 alkali-free mercuric oxide at boiling heat, as prescribed by 

 Alibegoff.* As pointed out by von Foullon and also by Ali- 

 begoff, contrary to certain still widely disseminated statements, 

 ammonium sulphide does not afford a good separation of 

 uranium from calcium. This is perhaps especially true if the 

 solution contains any phosphorus. Again, contrary to another 

 statement, it seems perfectly possible to separate uranium com- 

 pletely from alkalies by a few ammonia precipitations. 



The finally ignited and weighed U 3 O g was redissolved in 

 nitric acid, filtered if necessary (Si0 2 , A1 2 3 , Fe 2 3 ), and divided 

 into two parts of which the one was tested for the very little 

 P„0 5 usually present, and the other for vanadium by conversion 

 into sulphate, reduction by sulphur dioxide gas, and titration 

 by very dilute permanganate solution. 



Table of Analyses of Carnotite Ores. 



I. Copper Prince Claim, Roc Creek, Montrose Co., Colo. 



According to the donor of the specimen, Mr. J. P. Duling, I-a 

 is from the same lot as that from which Mr. Poulot obtained 

 the specimens afterwards analyzed by Friedel and Cumenge. 



II. Yellow Boy Claim, La Sal Creek, Montrose Co., Colo. 

 III. Yellow Bird Claim, La Sal Creek, Montrose Co., Colo. 



The last two claims belong to the same group and the ore is 

 from the same "blanket" (Yoilleque). 



I-b and Il-b, the first analyses made, are not strictly com- 

 j)arable with the other analyses since they represent the effect 

 of warm dilute hydrochloric acid, whose greater action is shown 

 by the nearly complete solution of the ferruginous admixture. 

 Cold, dilute nitric acid was used for the other analyses. 



*Ann. Chem. u. Phar., vol. ccxxxiii, 133, 1886; Zeit. fur anal. Chemie, xxvi, 

 632, 1887. 



