424- Messrs. Price and Nicholson on the Influence of the Hot-blast 



In the present communication it is not our intention to enter 

 upon the discussion of this subject generally, as we intend re- 

 serving this for a future communication, but to limit our remarks 

 to the consideration of the supposed influence of hot-blast in 

 augmenting the quantity of phosphorus, an element of almost 

 constant occurrence in pig-iron, and to the presence of which in 

 bar-iron the peculiar property of the metal known as cold short- 

 ness is attributed. 



In a paper published in the Quarterly Journal of the Chemical 

 Society*, and also in one read before the British Association in 

 ISiQtj by Mr. Wrightson, several analyses of cast iron, the pro- 

 duce of Staffordshire furnaces worked by hot, warm, and cold 

 blast, are given to prove that a larger amount of phosphoric acid 

 is reduced when hot-blast is employed. 



The increase in the per-centage of phosphorus in the ii'on 

 smelted with hot- over that with cold -blast is exhibited in the 

 following series of Mr. Wrightson's results : — 



The ores from which the iron was smelted were also analysed, 

 and found to contain the following per-centages of phosphoric 

 acid : — 



Binds. Blue flats. Penny earth. Gubbin. White iron stone. Wliite free. Black free. 



traces, traces. 1-00 0-32 095 0-90 trace. 



The increase in the amount of phosphorus indicated in the 

 above table as occurring in hot-blast iron, does not, in the ab- 

 sence of a knowledge of the relative quantities of the respective 

 ores employed, which vary as much as 1 per cent, in the quan- 

 tity of phosphoric acid which they contain, and also of an exami- 

 nation of the blast-furnace slag produced, appear to afford suf- 

 ficient proof in support of this opinion. 



Karsten %, in speaking of bog-iron ore, says that, when smelted, 

 the whole of the phosphate of iron is reduced to the state of 

 phosphide and absorbed by the iron. Berthier§, from experi- 

 ments conducted on a small scale, does not coincide with this 

 view, and considers that the difficulty of detecting small quan- 

 tities of phosphoric acid must account for its jiot appearing 



* Vol. i. p. 330. t Chem. Gaz. vol. vii. p. 4/8. 



X Handbuch der Eisenhuttenkunde, vol. ii. § 368. Berlin, 1841. 



§ Traitedes Essais par la Voie seche, vol.ii, p. 262. 



