136 Hillebrand and JRansome — Camotite and Associated 



factory results. They recommended washing with water con- 

 taining ammonium nitrate. 



The other method contemplated the quantitative removal of 

 vanadium by dry hydrochloric acid gas as already described 

 (p. 131). This had been shown to be perfect for alkaline pyro- 

 vanadates by Smith and Hibbs and it was hoped might succeed 

 even with such complex mixtures as the present. The distil- 

 lations were made on the crude ore and also on the nitric acid 

 solution after filtration from the insoluble matter and evapora- 

 tion to thorough dryness. The action is immediate in the 

 cold, copious red-brown vapors coming off and condensing in 

 part as a dark red liquid in the tube. Bat repeated distilla- 

 tions and the application of heat were required to effect com- 

 plete removal of the vanadium accompanied by the arsenic and 

 molybdenum. After each distillation the contents of the boat 

 had to be evaporated with nitric acid. The blue and green 

 colorations apparent on adding this acid showed that the hydro- 

 chloric acid gas had reduced a good deal of the vanadium to a 

 lower state of valence, and in this condition it was incapable 

 of forming the volatile body. 



A somewhat more satisfactory separation sometimes resulted 

 when this distillation method was combined with that of 

 Friedel and Cumenge by subjecting both the evaporated 

 uranium nitrate solution and the residue insoluble in water to 

 the action of hydrochloric acid gas. 



The distillates obtained by either way were evaporated with 

 sulphuric acid, the arsenic and molybdenum were separated by 

 hydrogen sulphide, and the vanadium was then titrated by 

 permanganate at a temperature near boiling and again after 

 reduction by sulphur dioxide gas. In one or two cases when 

 the temperature of distillation had been high and it was feared 

 some iron had passed over, the distillates were evaporated in 

 porcelain with nitric acid, transferred to a platinum crucible, 

 evaporated therein with sulphuric acid and fused with sodium 

 carbonate. The aqueous extract was then treated as above for 

 arsenic, molybdenum and vanadium. 



The separation of Friedel and Cumenge, while perhaps ade- 

 quate for technical purposes in ores free from phosphorus,* 

 does not in my hands give perfect satisfaction even then. It 

 is impossible to prevent a little of the vanadium, also of the 

 iron and aluminum, from going with the uranium, and on the 

 other hand a little uranium may stay with the vanadium. 



* With, even only half a per cent of P 2 5 many times that amount of U0 3 is 

 rendered insoluble in water after evaporation to dryness with nitric acid. The 

 compound formed is of a lemon-yellow color, which is masked by the separated 

 vanadic acid until this has been removed by ammonia. This insoluble body was 

 treated as follows in order to arrive at the P 2 6 and U0 3 it contained. After 

 solution in nitric acid the phosphorus was precipitated by ammonium molybdate, 

 and from the filtrate the uranium by three precipitations by ammonia. 



