412 Thornton, Jr. — Separation of Titanium from iron, etc. 



Table IV. 

 The Separation of Titanium from Iron, Aluminum, and Phosphoric Acid. 



Ti0 2 Fe^O.-: AI0O3 P 2 5 Ti0 2 H0SO3 Tartaric Volume 



taken taken taken taken found Error (1:1) acid ofsoln. 

 Xo. grm. grra. grm. grm. grm. grm. cm 3 grm. cm 3 



15 0-1065 0-2036 0-1127 0-0154 0-1070 +0-0005 30 2 400 



16 0-1066 0-2036 0-1127 0-0151 0-1068 +0-0002 30 2 400 



17 0-1065 0-1018 0-1127 0-0153 01067 +0-0002 40 2 400 



18 0-1067 0-1018 0-1127 0-0153 0-1069 +0-0002 40 2 400 



19 0-1066 0-2267 0-2254 0-0153 01069 +0-0003 40 2-5 400 



20 01066 0-2267 0-2254 0-0153 0-1073 +0-0007 40 2-5 400 



the solution has become colorless. Unless the iron is thus 

 reduced before precipitation, titanium will be in part thrown 

 down also.* Ammonium hydroxide is then added in decided 

 excess and more hydrogen sulphide introduced until the iron 

 has been completely thrown out as ferrous sulphide — leaving 

 the solution, however, alkaline to test-paper. The ferrous 

 sulphide is filtered off and washed with very dilute colorless 

 ammonium sulphide about ten times. To the filtrate is then 

 added 40 cm3 of sulphuric acid (1:1) and the hydrogen sulphide 

 thus liberated boiled out. After cooling to room temperature 

 the solution is made up with water to 400 cm3 and a 6 per cent 

 solution of " cupferron " added slowly with constant stirring. 

 The beaker is then set aside for the precipitate to settle. 

 After the precipitate has subsided the supernatant liquid is 

 tested by adding a few drops of the reagent. The formation 

 of a white precipitate of nitrosophenylhydroxylamine indicates 

 that the reagent had been added in excess ; whereas the forma- 

 tion of a yellow turbidity shows the precipitation to be incom- 

 plete. It is well also to test the filtrate. The precipitate is 

 collected on a paper filter — using gentle suction, and washed 

 twenty times with hydrochloric acid (made by diluting 100 cm3 

 of acid of sp. g. — 1"20 to one liter). After having been sucked 

 free of drainage water at the pump, the precipitate and filter 

 are placed in a tared platinum cruciblef and dried at 110° C. 

 With the crucible not quite covered by the lid the ignition is 

 begun with a very small flame. After the first violent gush 

 of smoke the heat is raised a little, when the destructive dis- 

 tillation will proceed quietly. After burning away the carbon, 

 the residual titanic oxide is brought to constant weight over 

 the Meker burner. In the paper;}; previous to this, where the 

 separation of titanium and iron only was under consideration, 

 the author has directed that the acidified filtrate from the 

 ferrous sulphide be partially neutralized with ammonium 



*Cathrein, A., Zeitschr. Kryst., vi, 243, 1882; vii, 250, 1883. 

 f A quartz crucible is also satisfactory for the ignition. 

 X Loc. cit. 



