370 Gooch and Havens — Volatilization of Iron Chlorides 



Art. XLII. — The Volatilization of the Iron Chlorides in 

 Analysis, and the Separation of the Oxides of Iron and 

 Aluminum; by F. A. Gooch and Franke Stuart 

 Hayens. 



[Contributions from the Kent Chemical Laboratory of Yale University — LXXXL] 



It is well known that metallic iron is easily acted upon by 

 an excess of chlorine at moderately elevated temperatures with 

 the formation of ferric chloride, and that the product of 

 the action of hydrochloric acid gas upon the metal is ferrous 

 chloride. Out of contact with air, or moisture, both chlorides 

 may be volatilized at appropriate temperatures—the ferric 

 chloride below 200° C. ; the ferrous chloride at a bright red 

 heat. If water vapor, or oxygen, or air be present during the 

 heating, both chlorides are partially decomposed with the for- 

 mation of non-volatile residues, ferric oxide or ferric oxy- 

 chloride. 



Analytical processes involving the volatilization of iron at 

 temperatures more or less elevated, in an atmosphere of chlo- 

 rine or hydrochloric acid, have been the object of considerable 

 attention. Thus, Fresenius,^ Drown and Shimer,f and Watts, % 

 have heated crude iron in chlorine to remove the metal and 

 leave the non-volatile constituents; and SainteClaire Deville§ 

 has employed hydrochloric acid to volatilize iron from mix- 

 tures of that metal with alumina (obtained by heating the 

 mixed oxides of iron and aluminum in hydrogen according to 

 Rivot),| exposing the mixture, contained in a porcelain boat 

 and placed within a porcelain tube, to the bright red heat of a 

 charcoal furnace — an operation which was bettered by Cooke's^f 

 use of a tube of platinum instead of the porcelain tube and a 

 gas blowpipe in place of the charcoal furnace. Sainte-Ciaire 

 Deville** showed, further, that ferric oxide may be converted 

 to ferric chloride and volatilized at the heat of the charcoal 

 furnace if the current of hydrochloric acid is sufficiently rapid ; 

 but the curious effect was observed that in a sufficiently limited 

 current of the acid no chloride whatever was volatilized, while 

 the amorphous oxide was converted to the highly crystalline 

 oxide of the same composition — a phenomenon which gave 

 rise to a theory of the natural formation of specular iron in 

 volcanic regions. 



Quite recently, Moyerff has made record of an unsuccessful 

 attempt (in the course of experimentation upon the volatility 



* Zeitschr. fur Anal. Chem., iv, 72. fJour. Inst. Min. Eng., viii, 513. 



i Chem. News, xlv, 279. § Ann. de Chim. et de Phys. [3], xxxviii, 23. 



1 Ann. de Chim et de Phys. [3], xxx, 188. ^[This Journal [2], xlii, 78. 



** Compt. Rend., lii, 1264. \\ Jour. Amer. Chem. Soc., xviii, 1029. 



