154 



S. RADCLIFF. 



a matter of fact, about 50 per cent, of the concentrates 

 consist of minerals almost free from radium and uranium, 

 this being the proportion of the material fused sent to the 

 dump each week. 



An approximately ten-fold concentration of the radium 

 is therefore effected by the two simple operations of fusing 

 the concentrates and dissolving the fused product under 

 proper conditions. 



In Table IV the relative activities per unit mass of the 

 concentrates, tailings and slimes are given. 



Table IV. 



Activity per 

 unit mass. 



Uranium oxide 



1-0 



Tailings 



0-007 



Concentrates 



0*06 



Slimes 



0*25 



Crude sulphate ... 



... ll'O 



The radio-active lead separated out on smelting the 

 sulphate has an activity approximately twice that of 

 uranium oxide when three months old. 



The whole of the radium in the concentrates must dis- 

 tribute itself between the tailings and the slimes. As the 

 tailings amount to five times the weight of the slimes, it 

 appears from the relative activities of the two products 

 that 86 per cent of the radium contents of the ore is con- 

 centrated in the slimes, 14 per cent, being rejected in the 

 tailings. 



So far I have done nothing in the separation of the other 

 radio-active bodies in the ore. I hope, however, to examine 

 a portion of the radio-active lead now being stored very 

 shortly, as its activity appears too high to be wholly due 

 to radium D and its products. Rutherford 1 states that 

 "radium D is separated with the large amount of lead 



E. Butherford, The Radio-active Substances, p. 511. 



