482 



METALLUEGY. 



the different alloys with copper, a gradual 

 change in properties may be observed as the 

 latter is increased in amount. Aluminum can 

 contain 10 per cent, of copper and still re- 

 tain most of its malleability. With more than 

 10 per cent., however, it becomes brittle, but 

 retains its white color up to nearly 80 per cent. 

 A number of remarkable and useful alloys are 

 made by mixing aluminum bronzes with nickel 

 in various proportions. These compositions 

 are said to be very ductile, and to have a te- 

 nacity of from 75,000 to 100,000 pounds per 

 square inch, with about 30 per cent, elonga- 

 tion. The addition of a few per cent, of 

 aluminum to common brass greatly increases 

 its tenacity and resistance to corrosion. The 

 alloys of aluminum seem well suited for anti- 

 frictional purposes, and are unexcelled for va- 

 4 rious household uses. The golden color of the 

 5-per-cent. bronze makes it very suitable for 

 plumbers' and similar fittings, and its resistance 

 to corrosion is greater than that of the mate- 

 rials used. For cooking-utensils and even 

 table-ware, these alloys are unsurpassed in 

 color and durability. The difficulty of solder- 

 ing the bronzes and the fact that they can not 

 be welded, are drawbacks to using them for 

 small manufactured articles. Pieces can, how- 

 ever, be united by certain jewelers' solders, 

 from which soft solders may be made by add- 

 ing brass. These bronzes have been made in 

 quantities large enough for testing by melting 

 together the correct proportions of copper and 

 aluminum, but this method is not commer- 

 cially economical with the ingredients at their 

 present prices. The most economical way 

 seems to be to make the alloys themselves as a 

 first product, and reduce the alumina in the 

 presence of copper. Among the processes em- 

 ployed for this purpose is that of the Cowles 

 Electric Furnace, in which the bronze is pro- 

 duced from a charge of about 25 pounds of co- 

 rundum, 12 pounds of charcoal and carbon, and 

 50 pounds of granulated copper. In general, 

 the 10-per cent, bronze works much better and 

 cleaner than copper and takes a more beautiful 

 polish, which it retains longer. The resistance 

 to corrosion in sea and mine water does not 

 seem to be well sustained. For resisting tor- 

 sion the 10-per-cent. bronze is substantially as 

 good as wrought-iron. The heat conductivity 

 of 5- and 10-per-cent. bronzes is very high, and 

 not much less than that of copper. The fric- 

 tion in journals of bronze is less and the tem- 

 perature higher, but the heat is very great as 

 compared with box-metal. 



The success attending the use of the Cowles 

 Electric Furnace in the production of alu- 

 minum and its alloys has induced inventors to 

 turn their attention to that method of obtain- 

 ing this metal. Dr. Fiertz, of Zurich, has ob- 

 tained two Swiss patents, in one of which the 

 improvements consist in fusing and decompo- 

 sing aluminum and other light-metal com- 

 pounds in an aluminous-lined or other vessel 

 by the direct action of the electric current, 



without the aid of external heat; and in the 

 other, they consist mainly in treating cryolite 

 or other metal-bearing substances by the action 

 of an electric current in a vessel provided with 

 a suitable lime cathode, while the anode is 

 formed in the shape of a cylinder or in seg- 

 ments, and is so placed in the inside of the ves- 

 sel as to be practically excluded from contact 

 with the air. Improvements have been made 

 in the Cowles furnace itself, in the adoption of 

 means by which the varying electrical resist- 

 ance of the charge in the furnace is made the 

 primary agency in actuating and controlling 

 the feeding of the material to be smelted or re- 

 duced, and the discharging of the products. 



Dr. Kleiner, of Zurich, has invented a pro- 

 cess for producing pure aluminum immediately 

 from the ore by direct electric action. His 

 method differs essentially from that of Mr. 

 Cowles, in that the latter depends upon the 

 heat produced by the application of the electric 

 current, while in the present case the separa- 

 tion is effected by the chemical power of the 

 current. The ore employed is cryolite, a 

 double fluoride of sodium and aluminum. It 

 is ground to a fine powder, and when exposed 

 to the action of the current has its aluminum 

 removed, leaving a double fluoride of sodium 

 which is soluble in water. After the process 

 has been carried as far as is commercially eco- 

 nomical, the slag is allowed to cool, and is then 

 broken up and washed. The metal comes out 

 in lumps, the soda-salt is dissolved, and can be 

 saved for conversion into caustic soda, while 

 the unreduced ore, which is insoluble, is dried 

 and returned to the bath. 



In a recently patented French process for 

 the extraction of aluminum from its oxide by 

 the combined action of carbon, sulphide of 

 carbon, and heat, aluminous carbon is obtained 

 by mixing powdered alumina with 40 per cent, 

 by weight of powdered charcoal or lamp- 

 black; to this mixture is added a sufficient 

 quantity of any oil or tar to form a thick 

 paste. The paste is placed in a closed vessel 

 capable of standing a high temperature, and 

 is calcined to a red heat for the purpose of 

 decomposing the oil or tar, and the coherent 

 mass of aluminous carbon thus obtained is 

 broken up into small pieces. The pieces are 

 placed in a closed vessel provided with pipes, 

 one of which leads a current of gaseous sul- 

 phuret of carbon into the mass until the reac- 

 tion is complete, and the other allows of the 

 escape of the carbonic oxide produced. The 

 sulphuret of aluminum thus obtained is treated 

 at a red heat in a closed vessel having pipes, 

 with a current of carbureted hydrogen. The 

 latter unites with the sulphur, producing sul- 

 phureted hydrogen, and leaving the pure alu- 

 ininuma. 



For the reduction of alumina, G-. A. Faurie 

 makes a paste of two parts of pure and pow- 

 dered alumina with one part of petroleum, 

 which, having been beaten up, is mixed with 

 one part of sulphuric acid. When the yellow 



