198 HALL AND SMITH— COLUMBIUM. 



[May 19, 



acid of definite specific gravity was added and allowed to stand in 

 contact with the hydrates for a definite time. The portion in- 

 soluble was filtered off, and the amount of oxide going into solu- 

 tion determined by precipitation with ammonium hydroxide, 

 igniting and weighing. The amount of titanium in the oxide 

 which went into solution was determined colorimetrically. 



In making these trials columbium oxyfluoride was used in which 

 the titanium oxide as compared with the columbium oxide was 

 .00095 gram Ti0 2 , or 0.41 per cent. The specific gravity of the 

 sulphuric acid used was 1.145. 



EXPERIMENTS. 



1. 1 gram ofK 2 TiF 6 , containing 0.3330 gram of Ti0 2 , was used 

 to obtain the hydrate. The latter was treated with 40 c.c. of 

 water and 70 grams of sulphuric acid. It dissolved completely in 

 fifteen minutes. 



2. 0.4450 gram of columbic oxide, in the form of hydrate, was 

 treated with 40 grams of water and 108 grams of sulphuric acid for 

 one hour. Only a slight precipitate was obtained with ammonium 

 hydroxide in the filtrate. It was not weighed but contained 

 .00032 gram of Ti0 2 , or .07 per cent, of the total oxide taken, or 

 one-sixth of the total Ti0 2 present. 



3. Columbic hydrate, containing 0.4450 gram of oxide, was 

 treated with 60 grams of water and 123 grams of sulphuric acid for 

 four hours. The portion which dissolved equaled 0.0060 gram = 

 1.33 per cent., and contained .000424 gram of Ti0 2 , or 7 per cent, 

 of the oxide dissolved and about one-fourth of the total titanium 

 present. 



4. The hydrate from three grams of columbium oxyfluoride, equiv- 

 alent to 1.35 grams of oxide, was allowed to stand in contact with 

 50 grams of water and 100 grams of sulphuric acid for seventeen 

 hours. The acid solution showed 0.0236 gram of oxide = 1.75 

 per cent., containing .000954 gram TiO, = 4 per cent, of oxide 

 dissolved or 17 per cent, of the total Ti0 2 present. 



5. Hydrate containing 0.445 g ram of oxide when treated with 

 57 grams of water and 85 grams of H 2 S0 4 (sp. gr. = 1.435) f° r 45 

 hours showed in solution 0.0500 gram =11.1 per cent., containing 

 0.0008 gram Ti0 2 =1.6 per cent, of the oxide dissolved or 43 per 

 cent, of the total Ti0 2 present. 



