PAPERS OX CHEMISTRY AND PHYSICS 227 



COXCEXTEATIOX OF KADIUM FROM CAEXOTITE 



OEES 



B. S. Hopkins and G. C. El'hle, University of Illinois 



Camotite is a potassium uranyl vanadate of essen- 

 tially the composition represented by the formula K2O. 

 2UO3.V2O5.8 H2O. All the mineral substances present are 

 valuable, but the most valuable component, radium, is 

 present in such a small proportion that it cannot be shown 

 readily in the fonnula. It requires a ton of relatively 

 rich camotite ore to produce 10 milligrams of radium. 

 It is very e^ddent then that any method which is efficient 

 in the removal of radium must be capable of effecting 

 practically 100 j^er cent extraction. It is also clear that 

 a veiy important part in the process will consist in the 

 concentration of the minute quantities of radium after 

 they have been removed from the great bulk of the or«. 



For the first step in the process, the United States 

 Bureau of Mines recommends the employment of nitric 

 acid, by the use of which practically all the radium to- 

 gether with most of the other valuable mineral consti- 

 tuents present is converted to the soluble form. The solu- 

 tion obtained in this manner is nearly neutralized, bar- 

 ium chloride is added, and the radium and barium are 

 precipitated by adding sulfuric acid. The precipitated 

 radium — barium sulfate is filtered off, and from the clean 

 solution uranium is precipitated, usually as sodium ura- 

 nate and the vanadium either as ferrous vandate or cal- 

 cium vanadate. 



The main advantage claimed for this jDrocess is the 

 high recoveiy of radium. The disadvantages arise from 

 the cost of nitric acid and the fact that there is only par- 

 tial extraction of vanadium. In large measure the cost 

 difiSculty is overcome by the fact that a very considerable 

 portion of the nitric acid may be recovered and used 

 again. If the main object in view is the extraction of 

 radium, this method is said to be especially efficient. 



The radium-barium sulfate, which contains only a very 

 small per cent of radium, must now be subjected to treat- 

 ment for the concentration of radium. The usual pro- 



