president's address — SECTION B. 97 



A pendant to the above method is a similar recent one, (u) which 

 aims at the same general object of circumventing the lining, but which, 

 recognising the true role assigned to the " basic " lining, supplants the 

 latter by water-cooled furnace walls. The process is, however, con- 

 ducted in a constructionally much inferior apparatus. This virtually 

 consists of an adaptation of the old Swedish fixed converter, water- 

 cooled in the tuyere region and in other places where a chemical attack 

 of the walls might take place, which is built together with an auto- 

 matically discharging foreheartb for the separation of matte and slag, 

 the whole under one reverberating rcof. The ores to be Bessemerised 

 with the assistance of the matte bath are fed through a charging-tube 

 situated above the Bessemer dome, in which tbey are preheated by the 

 escaping gases. Blast is only driven into the converter part. A heavy 

 layer of slag is maintained on the matte, and the blast is forced in, just 

 below the contact of matte and slag, so as to cause an energetic agitation, 

 with the greatest possible utilisation of the oxygen at the most service- 

 able place, close to the point assumed to be reached by the floating 

 siliceous ingredients in the ore. This process and the one above 

 mentioned, though not of a revolutionary nature, at least are first 

 attempts of note towards an emancipation from the acid lining, and, 

 as pioneers of a difficult subject, may be remembered with some interest. 



The " Seleiieur."— We have now arrived at the present-day state 

 of the copper-converting apparatus and its application, as far as they 

 can be touched upon here. One characteristic and important innova- 

 tion, however, remains to be mentioned, though its use is limited to 

 practically only one locality. The pneu7natic copper process could not 

 be truly an accelerated Welsh process if it gave no opporttmity for the 

 formation of copper " bottoms." This deficiency in the procedure 

 and plant so far described is fully made up bv M. David's latest form 

 of converter vessel, which he has c;tlled the " selecteur " — in allusion 

 to the working scheme which it supplants. The shape of the vessel 

 employed, also evolved at Eguilles, is spherical, with a spout or nose, 

 thus again bringinc down to a recent date one of Bessemer's early 

 forms (that of 185-5, never built), the special object of which was to 

 minimise radiation. This prototype, however, was to be blown by 

 means of an inserted tube, while the selecteur is supplied with a number 

 of bottom tuyeres. These are so aligned as to coincide with the elements 

 of an hyperbolic paraboloid, the idea being for the blast to give the bath 

 a gyratory motion. Laterally, halfway up its rounded side, the vessel 

 has a smaller, hemispherical, lined pocket, bolted on externally, and so 

 arranged that, by means of a communicating channel between the two 

 cavities, a portion of the contents of the larger can be let into the 

 smaller by properly rotating the whole. By this means the copper 

 first formed — which, as in the reverberatory process, contains most of 

 the gold and a large portion of the impurities in the matte — can be 

 mechanically separated from tbe rest at an early stage in the blow, 

 thus rendering the balance of the metal so much the cleaner. The 

 sulphides of arseni c, antimony, bismuth, nickel, cobalt, tin, lead, &c. — 



(«) \ Torkar's method, Austria, 1904. 



