RARE-EARTH ELEMENTS 



555 



A major problem in the rare-earth field, however, 

 is not one of scarcity of raw materials, but rather 

 of developing a better balance in the utilization of 

 all the rare-earth elements normally recoverable 

 from the ores. The ore minerals bastnaesite and 

 monazite contain the individual rare earths in char- 

 acteristic, though somewhat variable, proportions, 

 with cerium subgroup elements predominant. Thus, 

 a ton of bastnaesite may contain about 700 pounds 

 of cerium oxide but only II/2 pounds of europium 

 oxide. These relationships, which are established by 

 the natural distribution of the elements in the ores, 

 cause no problems when the demand for mixed or 

 separated elements is roughly proportional to their 

 abundance. If, however, an unusual demand arises 

 for one specific element, as for europium, its extrac- 

 tion can result in the unavoidable production of 

 other lanthanides in excess of existing requirements. 

 Increased uses for the more abundant rare earths 

 and significant uses for some of the scarce ones 

 would be of great value in stabilizing the industry, 

 and it is in the discovery of these uses that further 

 research is needed. 



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