president's address — SECTION B. 119 



As far as the completion of the step from ore to copper by this type 

 of treatment is concerned, Mr. HoUway was comparatively in advance, 

 for he might as well have brought the 50 per cent, matte which he blew 

 out of a 1.8 per cent, ore, in 1878. to a finish in the same vessel, had 

 he not too exclusively devoted his attention to regulus as a final product. 

 In fact, the Bessemerising of low-grade copper ores up to blister in the 

 converter vessel in one continuous operation is altogether within easy 

 reach of accomplishment with repeated additions of charges of raw 

 ore and silica, or with a sufficiently heavy lining, but it is necessarily 

 a tedious, costly, and quantitatively unsatisfactory operation, and, 

 therefore, is not being practised. The solution of the problem is being 

 worked on from the blast-furnace side of the question for the sake of 

 the rapid reduction of a large tonnage of ore, but, as remarked, it is 

 only in embryo still. It cannot be said that the considerable difference 

 in blast pressure between blast furnace and converter is a cause of 

 failure, although this difference is a prominent trait of the two present 

 practices. There is no fundamental reason why converter blast 

 pressures should not be used in the blast furnace, and, on the other 

 hand, the converter does not exclusively depend on its higher air- 

 pressure for its action. Pressure is merely a matter of the depth of 

 matte to be penetrated for complete absorption of the atmospheric 

 oxygen. A fundamental point of difference, however, resides in the 

 respective quantities of air required, and no doubt it is somewhat 

 hopeless to expect to force the full volume demanded by the entire 

 amounts of iron and sulphur (as far as they are actually oxidised), through 

 a small accumulation of matte at the bottom of a furnace shaft, with 

 the special intention of reducing metallic copper out of it with a modicum 

 of the air, while leaving all the rest of the blast available for the column 

 of charge in the shaft above. Nor is it quite apparent how the hearth, 

 can individually be supplied with a small quantity of air for the matte, 

 and, simultaneously, the shaft, also individually, with a vastly greater 

 volume sufficient for the ore. A pneumatic equilibrium injurious to 

 the proper reduction of the matte must inevitably assert itself at once, 

 unless the two portions of the furnace are wholly isolated from each 

 other. The problem will probabl)^ find its solution along this line, 

 in other words, by a compounding into one continuously operating, 

 but double structure, of the really essential features of the furnace 

 and the converter vessel. Unless this is done it even is difficult to see 

 how the descending matte, out of the ore. can be prevented from 

 interfering with the proper precipitation of copper out of the bottom 

 layer of matte. The modern, twofold practice, where the furnace 

 matte is taken to the converter vessel in a molten condition, is, further- 

 more, so simple and convenient in every respect that it may be doubted 

 if it can be improved by the substitution of a single compound appa- 

 ratus, in which the irregularity of work in the furnace portion must 

 always hamper the efficiency of the converter portion. 



But leaving this outlook into the future, let us return to the past. 



The intentional use of raw, unroasted pyrites in the blast furnace 

 is comparatively modern. It is one of the many creations of the move- 



