Thornton, Jr. — Separation of Titanium from Iron, etc. 413 



hydroxide. It should be here noted that in the light of the 

 farther experiments recorded above, this is, of course, entirely 

 unnecessary. 



On account of the small amounts of platinum that find their 

 way into the solutions during mineral and rock analysis, being- 

 derived from the platinum vessels by the attack of certain 

 fluxes (such as alkali pyrosulphate or a mixture of sodium car- 

 bonate and potassium nitrate) on prolonged fusion or by the 

 action of certain oxidizing agents (such as sodium manganate, 

 sodium chromate, etc.) on hydrochloric acid, and since Chatard* 

 in his modifications of the method of Goodif has recommended 

 the removal of platinum from the solution by hydrogen 

 sulphide prior to the final precipitation of the titanium ; it was 

 thought advisable to find out whether or not the titanic deriva- 

 tive of nitrosophenylhydroxylamine carried down appreciable 

 masses of platinum. Chlorplatinic acid was dissolved in water 

 so as to make a solution containing approximately one mgrm. 

 of platinum in every cubic centimeter. Table Y contains the 

 results of two experiments, which show that the precipitate has 

 little, if any, tendency to include platinum. 



Table V. 



The Separation of Titanium from Platinum. 



Ti0 2 Pt. taken TiO, H 2 S0 4 Volume 



taken (approx.) found Error (1:1) of soln. 



No. grm. grm. grm. grm. cm 3 cm 3 



21 0-1067 0-0100 0-1071 +0-0004 40 400 



22 0-1067 0-0100 0-1066 — O'OOOl 40 400 



The success of this analytical research has depended on three 

 very fortunate phenomena. First : the precipitate of the 

 titanium by the "cupferron" reagent is quantitative in the 

 presence of tartaric acid — a fact which obviates the necessity 

 of oxidizing the tartaric acid. Second : the separation of 

 titanium from aluminum is facilitated by tartaric acid to the 

 extent of greatly diminishing the concentration of free mineral 

 acid necessary. Third : a clean separation of titanium from 

 phosphoric acid can be accomplished under the same conditions 

 as the separation of titanium from aluminum, which seems to 

 the author remarkable when one considers the insolubility of 

 the basic phosphate of titanium even in decidedly acid media 

 and the difficulties in handling these two substances in solution. 

 The following points of merit are claimed for the method. 

 The whole analysis is accomplished by two precipitations — the 

 titanium being separated from both aluminum and phosphoric 



*Am. Chem. Jour., xiii, 109, 1891. 



fProc. Am. Acad. Arts and Sci., n.s., xii, 435, 1885. See also Hillebrand, 

 Bull. U. S. G. S., 422, 97, 107, 1910. 



