638 



steiger: precipitation of zirconium phosphate 



The standard zirconium solution used was made by preparing 

 from native zircon the double fluoride of zirconium and potassium. 

 After this salt had been purified by repeated crystallization it 

 was decomposed with sulphuric acid and the fluorine was driven 

 off" by heat. Its strength was determined by precipitating the 



TABLE I 

 Precipitation of ZrP207 in Presence of Sulphuric Acid 



zirconium with ammonia, filtering and igniting the precipitate, 

 and weighing the residue as oxide. The volume of the solution 

 finally used in each experiment was 100 cc, and to conform with 

 conditions met in practice, it was made up in part of hydrogen 

 peroxide. The sulphuric acid was added to the solution in vary- 

 ing quantities, and the zirconium precipitated by the addition of 

 microcosmic salt. The solutions were constantly stirred while 



