JOURNAL ^ 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VIII DECEMBER 4, 1918 No. 20 



CHEMISTRY. — A note on the precipitation of zirconium phos- 

 phate. George Steiger, Geological Survey. 



The recent interest in the determination of zirconium seems 

 to justify the publication of the results of some laboratory work 

 done several years ago to determine the allowable acidity of a 

 solution in which zirconium phosphate may be quantitatively pre- 

 cipitated. The work was done to determine more exactly the 

 conditions necessary when applying this method to the analysis 

 of rocks, which contain only small percentages of zirconium, and 

 although the quantities involved were small the work showed 

 that the composition of the phosphate ranges between limits so 

 wide that unless conditions of precipitation are fully determined 

 and rigorously maintained the results of such work can not be 

 used in a gravimetric determination. 



As the main object of this precipitation was the separation of 

 zirconium from titanium, iron, and other metals in a rock, no 

 effort was made to determine the conditions under which zir- 

 conium phosphate of constant composition may be precipitated. 



In determining quantities of zirconium so small as those found 

 in the average rock the analyst can obtain results that are suf- 

 ficiently accurate by assuming that the composition of the ignited 

 phosphate is ZrP207, and that it contains 46.32 per cent of Zr02. 

 The results are given in the hope that they may be of service 

 to those who are required to determine larger quantities of 

 zirconium. 



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