150 S. RADCLIFF. 



(a) Recovery of the Uranium. 

 The clear solution containing the uranium and much of 

 the iron and other bases in the concentrates, together with 

 a large amount of sodium salts, is fed into a series of vats 

 containing a measured excess of a mixture of carbonate 

 and bicarbonate of soda ; and heated and agitated by means 

 of steam jets. The iron, with most of the other bases 

 present is precipitated, while the uranium goes into solution 

 together with some of the rare earths. The bulky iron 

 precipitate is separated partly by settlement and partly by 

 means of vacuum filters. It is difficult to handle and can- 

 not be washed effectually, a portion of the uranium is 

 therefore unavoidably discarded along with this precipitate. 

 The uranium solution is made just acid with sulphuric acid, 

 heated, and the carbon dioxide expelled by a brisk current 

 of air. The uranium is then precipitated by the addition 

 of ammonia. The ammonium uranate is thickened some- 

 what in conical settling tanks and then further thickened 

 to a pulp in a hydro extractor. This pulp is dried and 

 dehydrated in large muffles. The dehydrated product is 

 broken up and washed repeatedly with hot water. This 

 treatment removes the bulk of the sodium salts, and a pro- 

 duct is obtained which on drying contains about 75 per cent, 

 of U 3 8 . An analysis of this, together with that of the 

 iron precipitate, is given in Table II. Prior to analysis the 

 iron hydroxide was twice dissolved and re-precipitated 

 with ammonia to free it from the large amount of sodium 

 salts present. The washed precipitate was dried, ignited 

 and analysed. 



Table II. 



Insoluble matter 



Titanium dioxide 



Ferric oxide ... 

 Uranoso uranic oxide 



Uranium 

 Product. 



3*0 



Iron 

 Precipitate. 



... 



8*11 



9*41 



74*65 



76*6 



2*7 



