COAL AND IRON OF CTJTTACK. ' IJ 



I have said that no flux is added to the mixture of ore and chai'coal 

 The ash of the charcoal used in these operations. Of course there must 

 must act as a fl.ax. ^^ ^ certain amount of ash in the charcoal, which 



in all probability consists principally of carbonate of potash and soda 

 and a little lime ; and this will doubtless act, and act most effectively, 

 as an. admirable flux, taking up a part of the silica; but the quantity 

 combined with charcoal is too small to have any very appreciable effect 

 on the result in diminishing the loss of iron. 

 The chemical reactions in the furnaces are simply these. Supposing, 

 Chief reducing agent ^ ^ ^0^ generally believed by those who are the 

 carbonic oxide. ^^^^ authorities on these matters, that carbonic 



oxide is the principal agent in reducing the ore, the first result of the 

 Chemical action in application of the heat is to promote the union of 

 the furnace. ^y^e Oxygen of the air with the carbon of the 



charcoal, forming carbonic oxide (Co or 0.) The ores used being, as we 

 have already explained, almost exclusively composed of the peroxide of 

 iron and silica, the ash of the charcoal, left free by the separation of 

 the carbon, takes up a proper proportion of the silica of the ore, leaving 

 still the larger portion. At the same time the peroxide of iron is 

 resolved into oxygen and the protoxide of iron, the whole of the oxygen 

 thus set free uniting with the carbonic oxide and forming carbonic 

 acid which is driven oft. 



A portion of the remaining protoxide of iron is again fm-ther resolved 

 into oxygen and iron, the oxygen, as before, uniting with a further 

 proportion of carbonic oxide, and passing off in the state of carbonic acid, 

 and the iron remaining ; while the other portion of the protoxide unites 

 with the unreduced silica and forms the silicate of the protoxide of iron. 

 This is the ordinary slag of such furnaces, the silicate of the protoxide 

 of iron, probably in the form of the tribasic silicate Fe' bi. * 



* This is the same as the " tap cinder" of puddling furnaces, which containa no lea 

 than 55 per cent, of iron. 



O 



