TECHNOLOGY. 



By WILLIAM H. WAHL, Ph.D., 



Philadelphia, Pa. 



THE DUPUY DIRECT PROCESS. 



This process, which was first publicly announced at the 

 monthly meeting of the Franklin Institute in November, 

 1877, has been for nearly a year experimentally tested at 

 Pittsburgh, and with such promising results as to justify one 

 of the largest establishments of that city in erecting a plant, 

 consisting of crusher, mill, furnaces, forge, etc., to test it 

 commercially. The following gives in brief the novel feat- 

 ures of the plan. Mr. Dupuy makes a suitable mixture of 

 ground ore, flux, and coal-slack (and alkalies), and introduces 

 the same into sheet-iron canisters of annular form, so that 

 the heat of the furnace may penetrate the mixture from both 

 the outer and the inner surface. The object sought to be at- 

 tained by this plan is to secure the advantages of the close 

 pot by employing a protecting envelope wdiich will with- 

 stand the high heat required for the reduction, and which, 

 when the operation is completed, may be welded up with 

 the metal. 



The inventor describes three methods of working: the 

 process, according to the purpose for which the metal is 

 designed : 



1. For steel-making, the canisters are charged on end into 

 the furnace, on a layer of coke a few inches in thickness. 

 When reduced (in from five to seven hours), it forms a very 

 firm metallic mass, wdiich is removed and hammered, or 

 thrown into a squeezer and rolled into muck-bar. The lat- 

 ter is reheated, cut up, piled, and put into the steel-pot. 



2. The reduced metal may be remelted in a Siemens open 

 hearth, with or without the usual carbonizing bath of pig 

 and spiegel. 



3. The metal, when reduced, may be melted down in the 

 same furnace and carbonized with pig-iron. The following 



