RADIUM AND URANIUM 

 THEIR ORES AND OCCURRENCE IN NATURE 



BY R. A. F. PENROSE JR 



INTRODUCTION 



The following article is intended to give a short description of 

 the occurrence of radium and uranium in nature. The brief space 

 available for it does not permit the discussion of all the chemical 

 and physical phenomena manifested in the origin of radium from 

 the disintegration of uranium through the intermediate element 

 ionium, and of the various products of the disintegration of radium 

 itself, with the formation of various more or less temporary prod- 

 ucts, and with perhaps the eventual production of lead. These 

 subjects are treated in many published papers and textbooks. The 

 present article is confined largely to a discussion of the minerals 

 and other ores from which radium and uranium are derived, and 

 of their geographic and geologic distribution. 



RELATION OF RADIUM AND URANIUM 



Radium is a metal and is a product of the disintegration in nature 

 of the metal uranium. Both radium and uranium are elements. 

 Radium has been isolated in its metallic state, but is not used in 

 that form and is known better in the form of its salts, among the 

 most important of which, so far as their uses are concerned, are 

 the bromide, chloride and sulphate. 



Wherever uranium occurs in nature, radium is associated with 

 it in certain definable quantities. Uranium can contain, however, 

 only a certain maximum amount of radium at a time, and when it 

 has reached this stage, the radium and uranium ratio is said to be 

 in equilibrium. In this condition the amount of radium per gram 

 of uranium has been calculated by Rutherford to be 3.4 x icr 7 

 gram. 1 This corresponds to 1 gram of radium element to about 

 3000 kilograms of uranium element, or 1 part of radium element to 

 about 3,000,000 parts of uranium element. Uranium minerals as 

 mined are usually impure and carry only a small percentage of 

 uranium element, so that the ratio between radium and the crude 

 uranium ore may be 1 to several or many times 3,000,000. 



1 E. Rutherford, Radio-Active Substances and Their Radiations, p. 462. 



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