70 SOME PRINCIPLES AND METHODS OF ROCK ANALYSIS, [bull. 176. 
should bo in a small flask, is now added hydrogen peroxide to oxidize 
the titanium, and then a few drops of a soluble orthophosphate solution. 
The flask is set aside in the cold for twenty-four to forty-eight hours. 
If the color bleaches after a time, more hydrogen peroxide should be 
added. Under these circumstances the zirconium is thrown out as 
phosphate and collects as a flocculent precipitate, which at this stage 
is not always pure. No matter how small or insignificant, it is col- 
lected on a filter, ignited, fused with sodium carbonate, leached with 
water, the filter again ignited, fused with very little acid potassium 
sulphate, brought into solution in hot water with a few drops of dilute 
sulphuric acid, poured into a flask of about 20 cm. 3 capacity, a few 
drops of hydrogen peroxide and of sodium phosphate added, and the 
flask set aside. Titanium is now almost never present, and the zirco- 
nium appears after a time as a white flocculent precipitate, which can 
be collected and weighed as phosphate. For the small amounts usually 
met with it is safe to assume that it contains 50 per cent of Zr0 2 (51.8 
by theory). If the amount is rather large, it may be fused with sodium 
carbonate, leached, ignited, fused with acid potassium sulphate, repre- 
cipitated by ammonia, and weighed as Zr0 2 . Certainty as to its iden- 
tity can be had by again bringing it into solution, precipitating by 
ammonia, dissolving in hydrochloric acid, evaporating to a drop or 
two, and testing with turmeric paper or by a microchemical reaction. 
With the very smallest amounts no color can be obtained by this tur- 
meric-paper test, which, however, responds readily to as little as 1 
milligram of dioxide and with proper care for as small an amount as 
0.3 milligram (Dr. Ii. N. Stokes). No element other than thorium is 
ever likely to contaminate the zirconium thus precipitated. 
In Bailey's experiments the precipitation was not made by addition 
of a phosphate, but is said to be due solely to the hydrogen peroxide, 
the precipitate being a hydrated peroxide, Zr 2 O r „ or ZrOg. 1 My own 
efforts to secure a precipitate in acid solutions of zirconium sulphate 
by hydrogen peroxide alone were unsuccessful, perhaps for lack of a 
sufficiently strong peroxide. The ability to obtain the zirconium free 
from phosphoric acid would certainly be a great improvement on the 
method described above. 
Were it not for the necessity of working in a weakly acid solution, 
the separation of zirconium could be made in the same portion in which 
the titanium is colorimetrically determined. 
OTHER METHODS OF SEPARATING ZIRCONIUM. 
Streit and Franz 2 claim to secure complete separation of titanium 
from iron and zirconium by boiling the neutralized solutions of the 
i Bailey, Chemical News, Vol. LX, p. 6, 1889. 
2 Jour, fur prakt. Chemie, Vol. CVIII p. 65, 1869. 
