Thornton, Jr. — Separation of Titanium from Iron, etc. 407 



Art. XXXIY. — The Separation of Titanium from Iron, 

 Aluminum, and Phosphoric Acid toith the Aid of the 

 Ammonium Salt of Nitrosophenylhydroxylamine ("Cup- 

 ferron "J y by William M. Thornton, Jr. 



[Contributions from the Kent Chemical Laboratoi'y of Yale Univ. — cclvii.] 



It has been shown by the author- that titanium can be 

 quantitatively precipitated in solutions moderately acidified 

 with sulphuric acid and containing also tartaric acid by the 

 ammonium salt of nitrosophenylhydroxylamine (" cupferron "). 

 Making use of this fact, an indirect separation of titanium from 

 iron has been accomplished. In this method, after precipitat- 

 ing the iron as ferrous sulphide by ammonium sulphide in the 

 presence of ammonium tartrate and filtering from the aforesaid 

 ferrous sulphide, the iron free filtrate is acidified with sulphuric 

 acid, the hydrogen sulphide boiled out, and the titanium pre- 

 cipitated in the cold by the "cupferron" reagent. The yellow 

 precipitate thus produced is collected and ignited to titanic 

 oxide. At the close of the article it was stated that it would 

 seem that there should be no great difficulty attending the 

 separation of titanium from iron, aluminum, and phosphoric 

 acid. Experiments with a view to accomplishing these separa- 

 tions have been fraught with very interesting and very gratify- 

 ing results. 



Although Schroderf has made the statement that titanium 

 and zirconium could be quantitatively precipitated by the 

 "cupferron" reagent, no experimental data have appeared on 

 the subject until Bellucci and Grassi^: showed that titanium 

 could be quantitatively thrown down by the reagent and that a 

 clean separation of titanium from aluminum could be brought 

 about by a single precipitation in acid solution. Their results 

 leave little to be desired for accuracy. But it is indeed sur- 

 prising that these writers do not give in any but the most in- 

 definite terms the acid concentration or the absolute volume of 

 the solutions in which the titanium was precipitated. They 

 say that the solution should be notably but not excessively acid 

 with either sulphuric or hydrochloric acid. Again, under the 

 separation of titanium from aluminum they say that the same 

 acidity was used for the separation as for the precipitation of 

 titanium alone, and that the precipitate was washed first by 

 decantation and then on the filter with very dilute hydrochloric 

 acid. Just how large a quantity of either of the above two 

 acids can be employed and the precipitation of the titanium 

 still be complete has not yet been determined. But the author's 

 experiments have clearly demonstrated that if the concentra- 



* This Journal, xxxvii, p. 173, 1914. 



•f Zeitschr. anorg. Chem., lxxii, 89, 1911. 



% Gazzetta Chimica Italiana, Anno xliii, Parte I, 570, 1913. 



