RUTILE. 175 



93. RUTILE.* 

 Ti0 2 . 



In order to obtain pure titanic acid from rutile, the 

 same method may be employed as for titanic iron ; the 

 first process is especially applicable to this purpose. 



Or the very finely-powdered rutile is fused in a 

 platinum crucible with six times its weight of 

 bisulphate of potassa. The mass must then dissolve 

 completely in cold water. If the water is heated to 

 ebullition the titanic separates, and by long continued 

 boiling the precipitation is complete. Thus obtained 

 it is nearly soluble in the acids. 



Another process consists in converting the titanic 

 acid into bichloride. The very finely-powdered rutile 

 is mixed with ignited lamp-black (1J part of carbon 

 for 5 parts of rutile) and so much starch-paste as will 

 suffice to form a plastic mass. This is moulded into 

 cylinders about 1 or 2 inches long, and J of an inch 

 thick, which are slowly dried. They are then 

 thoroughly ignited in a covered crucible, and, while 

 hot, before they have absorbed any moisture, intro- 

 duced into a tube of porcelain or of hard glass. A stream 

 of dry chlorine is passed in at one end of the tube, 

 while the other opens into a cooled receiver furnished 

 with an egress-tube. As soon as the apparatus is filled 

 with chlorine, the tube is heated to bright redness, 

 and the separation carried on till no more drops of 

 bichloride of titanium distil over. The carbonic 

 oxide and excess of chlorine are passed into a small 

 quantity of alcohol, which absorbs the latter. 



The bichloride of titanium, which has a brown 

 color due to sesquichloride of iron, is poured into 

 a small tubulated retort containing some mercury or 



* Occurs most abundantly at St. Yrieix, in France, and may be 

 purchased very reasonably. 



