90 president's address — SECTION B. 



with siliceous ores. But, irrespective of this special utilisation of large- 

 converters, their size apparently has not yet reached its limit, for we 

 read of one now being experimented with at Great Falls, Montana, of 

 an elliptical cross-section, 9ft. by 10ft., which is expected to double 

 the duty of a single lining in terms of metallic copper by raising it 

 from 15 tons to 30 tons, without, at the same time, requiring more 

 than the same duration of blow. 



Needless to say, water-jacketing the vessel was experimented 

 with, v^rticularly in the eady American d.iys.(5) It is difficult to see 

 what the incentive was, in view of the fact that the loss of heat by 

 radiation is small, and a mere bagatelle compared with that suffered 

 through the escaping gases, and the loss by convection in the water 

 would have been greater. Furthermore, the endeavor to prolong the 

 life of the linings by cooling them is an elementary chemical fallacy, 

 in view of the absolutely autonomous conditions as to slag-formation, 

 and heat-development which obtain within the converter. As might 

 have been expected, the trials with the water- jacketed shell, as well 

 as of the water-cooled pipe-coil buried in the lining, both only yielded 

 failures. 



As regards the tilting mechanism, the earlier experimental forms 

 having outgrown the use of hand-power, or of direct belt-driving by 

 pulley or gearing on the converter axle, adaptations of the hydraulic 

 mechanism current in steel practice universally took the place of these. 

 At first the horizontal rack and pinion arrangement was in favor, 

 latterly the vertical one is more used, being, in fact, necessitated by 

 the special mechanical problem presented by the horizontal converter 

 mounted on rollers. But this portion of the apparatus is far from 

 perfect, involving as it does too many inefficient elements, such as 

 pressure-pumps wastefully worked, and the intervention of accumu- 

 lators or intensifiers, at best crude combinations for the supply of 

 hydraulic power, not to mention the heavy losses incident to its 

 transmission through the pipe-.system, valves, &c. Converters of the 

 present day, now being built under progressive direction, are receiving — 

 and those of the future will, preferably, always be supplied with — 

 individual electric motors direct connected to them. 



The troublesome question of the con"\^eyance of the molten pro- 

 ducts, i.e., ma.tte, slag, and bhster, to and from the vessel involved, 

 and still involves, considerable hand-labor. It assumes formidable 

 proportions where the production is large, and is now solved in such 

 establishments by the extensive use of electrically carried ladles. The 

 mo?t modern practice in regard to the slag is again to pour it into 

 casting-machines, built after the style of platform-conveyors, on which 

 it is chilled by water, and which transport it to storage-bins for blast- 

 furnacing. The blister is commonly still poured direct from the con- 

 verter into mould? mounted on carriages ruii underneath the vessel : 

 the old large ingot-shape of bars, however, having recently been re- 

 placed, for argentiferous blisters, by that of flat cakes, in which the 



(s) H. W. Hixon, " Notes on Lead and Copper Smelting and Copper-converting," 



1897. 



1 



