IRON ORES. 



BY JOHN BIRKINBINE. 



[John Birkinbino, prosident of the Franklin institute; born in Pennsylvania, ISM; 

 educated at Polyteehnic college of Pennsylvania; became assistant engineer with th<' 

 Philadelphia water works in 1870, and since has been the leading American authority 

 on this branch of engineering, having designed and constructed important water sup- 

 plies, water power and blast furnaces; is expert on iron and manganeses ores for the 

 United States geological survev; president American Institute of Mining Engineers, 

 1891-3.] 



The phenomenal record made in producing pig iron in 

 the United States naturally invites attention to the materials 

 entering into the manufacture of pig metal, the character 

 of these materials, and the sources from which they are ob- 

 tained. Fuels, iron ores, and fluxes, components of com- 

 mercial pig iron, in passing through blast furnaces, produce 

 either pig iron in merchantable form or liquid metal, to be 

 carried to Bessemer converters or open hearth furnaces. 

 In 1902 an effort was made on behalf of the Canadian govern- 

 ment in equating bonuses to iron industries, to discriminate 

 against liquid metal being classed as pig iron, but the conten- 

 tion was not sustained, and commercially the entire product 

 of blast furnaces smelting iron ore is considered and reported 

 for statistical purposes as pig iron. 



In the manufacture of pig iron a considerable quantity 

 of rolling mill cinder, roll scale, etc., is produced" which is 

 also employed practically as ore. Some blue billy or purple 

 ore, resulting from the calcination of pyrites and the resid- 

 uum from roasting ferriferous and manganiferous zinc ores, 

 are also utilized. Some iron ore is employed for other pur- 

 poses than for the manufacture of pig iron. It forms an 

 important part of the charge of many open hearth steel fur- 

 naces, and is used also for fix in puddlmg and other furnaces, 

 for flux in silver smelting, and in making metallic paints. 



The active demand for iron ore to maintain in operation 

 the blast furnaces of the United States, and the expectation 

 that this demand would continue, was responsible to a great 

 extent for the phenomenally large output of the iron ore 



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