152 S. RADCLIFF. 



scale, to see if the sulphates in the slime could be reduced 

 by heating the material with carbonaceous substances, or 

 else in a current of some reducing gas, but the results so 

 far have not been encouraging. 



The crude sulphate is fused with carbonate of soda in 

 large graphite pots, and the product digested with hot 

 water. The insoluble residue after picking out most of the 

 metallic lead is thoroughly washed, and heated with hydro- 

 chloric acid. The solution is evaporated to dryness to 

 dehydrate the silica, the residue moistened with acid and 

 digested with hot water and the silica filtered off. 



It was found that the method of converting the sulphates 

 to carbonates by boiling with concentrated soda solution 

 was altogether too slow, and the fusion method has the 

 further advantage of removing most of the lead in the 

 metallic state. This lead which is, of course, radio-active 

 (Table IV) is being stored for examination later. The hydro- 

 chloric acid solution, containing the radium and barium, 

 together with large amounts of lead, iron, and acid earths, 

 was formerly treated by the ordinary analytical methods 

 for the removal of the impurities prior to precipitating the 

 radium and barium as carbonates. Bulky precipitates, 

 difficult to handle and wash were obtained ; this procedure 

 has been abandoned, and a method due to Soddy 1 is now 

 used with very satisfactory results. 



The chloride solution is saturated with hydrogen chloride 

 and the barium and radium are thrown down nearly free 

 from other elements. The crystalline precipitate is filtered 

 off, freed by suction from most of the adhering liquid and 

 dried. It is dissolved in water, the small amounts of lead, 

 iron, etc., still remaining, removed, and the mixed carbon- 

 ates of barium and radium finally dissolved in hydrobromic 

 acid for fractionation. About 1500 grams of dry chloride, 



1 F. Soddy, Chemistry of Radio Elements, p. 45. 



