108 Browning, etc. — Tellurium, Arsenic, etc. 



II. 



The separation of iron in the ferric condition, thallium in the 

 thallic condition, titanium, and zirconium is made by Noyes 

 and Bray* by dissolving the hydroxides in hydrochloric acid 

 1*12 sp. gr. and shaking the solution with ether; the ferric 

 and thallic chlorides dissolving in the ether and the chlorides 

 id' titanium and zirconium being left in the water layer. The 

 iron and thallium are separated by sulphurous acid and potas- 

 sium iodide and the titanium and zirconium by sodium phos- 

 phate in the presence of hydrogen dioxide. 



This method gives good results but is slow in manipulation 

 and inconvenient and difficult to carry out successfully in the 

 hands of a large class of students lacking experience in such 

 procedures. 



As a substitute we present the following method which has 

 given satisfaction and rapidly obtained results: — 



The hydroxides are dissolved in sulphuric acid and hydro- 

 gen dioxide added, a red coloration indicating titanium. The 

 solution is then made faintly alkaline with sodium hydroxide 

 and sodium phosphate is added. Sulphuric acid containing 

 hydrogen dioxide is added to acidity, the latter reagent serving 

 to keep the titanium in the higher condition of oxidation. 

 The zirconium phosphate remains as a precipitate and is filtered 

 off. After the zirconium is removed the filtrate obtained is 

 treated with sodium hydroxide which precipitates the iron and 

 thallium. After these are removed the alkaline filtrate con- 

 taining the titanium is acidified with sulphuric acid and treated 

 with sodium sulphite and a little more sodium phosphate, when 

 the titanium phosphate appears. The precipitated hydroxides 

 or phosphates of iron and thallium are dissolved in sulphuric 

 acid, the solution treated with sodium sulphite and the thallous 

 iodide precipitated by potassium iodide. The filtrate from the 

 thallous iodide is boiled to remove sulphur dioxide, treated 

 with hydrogen dioxide and again boiled to remove iodine and 

 oxidize the iron, and then with potassium sulphocyanide to 

 identify the iron. 



*Jour. Arner. Chem. Soc, xxx, 481. 



