444 



METALLURGY. 



methods is beginning to excite considerable at- 

 tention in the engineering world, because of the 

 extraordinary facility with which such articles 

 as sheets, tubes, rollers, wire, and tape for elec- 

 tric-lighting and telegraphic purposes can be 

 produced in one operation, and of qualities 

 hitherto unattainable. When an anode is com- 

 posed of a mixture or an alloy of several metals, 

 and the electric current is passed through, the 

 various compound metals are not, as a rule, oxi- 

 dized and dissolved simultaneously. They are 

 attacked in a certain order, depending upon the 

 energy which they develop when combining with 

 oxygen, and dissolved in the acid of the solu- 

 tion. The metal which is attacked first is that 

 which by its oxidation creates the greatest en- 

 ergy, or which, if used as one of the elements of 

 a primary battery, would develop the highest 

 electromotive force ; and so on in regular order. 

 In deposition the reverse order prevails, and the 

 metal is first deposited, the separation of which 

 from the solution requires the least amount of 

 energy. The list of the principal metals found 

 in combination with copper includes, in the order 

 in which they would be dissolved in the electro- 

 lytic process, manganese, zinc, iron, tin, cadmium, 

 cobalt, nickel, lead, arsenic, bismuth, antimony 

 (copper), silver, gold ; copper having only silver 

 and gold below it. The order in which they 

 are deposited may be found by reading the list 

 backward. The facility with which copper can 

 be refined is due to its low place in the list ; for 

 under the ordinary circumstances of deposition 

 the silver and gold do not oxidize and dissolve 

 in the electrolyte, but fall to the bottom of 

 the bath. The copper, though chemically pure, 

 is of a crystalline character, and possesses but 

 little cohesive strength. It is therefore, in its 

 deposited condition, unsuitable for the manu- 

 facture of goods. Numerous experiments have 

 been made for securing the deposition of copper 

 in a tough, dense, and reguline condition at the 

 same time that it is being refined. Practical 

 success has been attained by the process of the 

 Messrs. Ehnore of continuously burnishing the 

 copper while it is being deposited without re- 

 moving the cathode from the bath. A mandrel 

 of iron, or preferably of copper, is mounted on 

 insulated bearings in the tank or bath, and a 

 burnisher consisting of a small prism of agate is 

 caused to travel, like the cutting tool in a lathe, 

 along the surface of the mandrel in a direction 

 parallel to its axis. While the current is pass- 

 ing the mandrel is caused to revolve. As the 

 copper is deposited on the revolving mandrel the 

 burnisher presses with even but gentle force on the 

 surface, and breaks down the crystalline forma- 

 tion, converting the deposit into a dense regu- 

 line metal of greater specific gravity than ordi- 

 nary sheet copper. Although the copper is de- 

 posited in this process in the form of a tube, 

 the product is applicable for a considerable 

 variety of purposes. Besides articles of a cir- 

 cular section, sheet copper, tape for electric 

 lighting, pots and pans of circular section and 

 with flat or curved bottoms, cartridge cases for 

 heavy and quick-firing guns, and high-conduc- 

 tivity wire, can be produced by simply cutting and 

 drawing without melting the metal. The in- 

 genious device of severing the continuity of the 

 metal at different thicknesses of the deposit, 



either by oxidizing the surface or by interrupt- 

 ing or reversing the current, makes it possible 

 to produce several sheets upon a single mandrel 

 from the tank. 



Considerable advances have been made during 

 the past three years in reverberatory practice for 

 smelting copper. Furnaces have been enlarged, 

 better methods have been adopted for the re- 

 moval of the slag, and decided improvements 

 have been made in other directions. The great- 

 est obligations for such service are due, accord- 

 ing to E. D. Peters, in his " Modern Copper Smelt- 

 ing," to Mr. Richard Peters, of the Boston and 

 Colorado Works, at Argo, Colorado. By means 

 of them the capacity of the reverberators has 

 been increased from 10 tons to more than 28 

 tons a day. The improvements involve the con- 

 sumption of more fuel than was used in the old 

 furnaces, but the increase is considerably less in 

 proportion than the gain in capacity. 



Ferdinand Allard's method of tempering cop- 

 per has borne well the tests to which it has been 

 subjected by the British Admiralty. Officers of 

 the Canadian militia, including Major-General 

 Herbert, having examined cutting tools made by 

 it, have expressed surprise at the fine edge ani 

 hardness attained in them. The Lords of the 

 Admiralty in England manifested great satisfac- 

 tion at the results of the experiments conducted 

 with the trial sheets which the inventor sent 

 over to them. At the Canadian rifle ranges a 

 bullet fired from a distance of 40 yards was 

 shattered into fragments by its impact with the 

 hardened copper. Another bullet was flattened 

 and remained imbedded in the sheet, If lines in 

 thickness, which it merely indented a trifle, with- 

 out causing any cracking. 



An electrolytic direct process for the reduction 

 of copper and silver ores, introduced by Dr. Ilo'pf- 

 ner, is highly spoken of. The fundamental prin- 

 ciple of it is the use of chlorine. A solution of 

 protochloride of copper, mixed with chloride of 

 calcium or chloride of sodium, is subjected to the 

 action of the electric current. Besides obtaining 

 the metal electrolytically, a lixivium is produced 

 which is capable of lixiviating copper, silver, bis- 

 muth, etc., from sulphur ores, and, on its return 

 to the_precipitation apparatus, is again ready to 

 precipitate metal and produce lixiviations. 



The characteristic feature of the Siemens and 

 Halske copper process is the use of a liquid which 

 dissolves the copper contained in the ore, and 

 gives it up when subjected to the electric cur- 

 rent, whereby its solvent capacity is restored, so 

 that the same liquid may be used indefinitely. 

 The solvent agent employed is ferric sulphate, 

 which is partially reduced to the ferrous salt, 

 with an equivalent production of cupric sulphate. 

 By electrolyzing the copper, salt alone is decom- 

 posed, and the ferric sulphate is renewed. 



T. D. Bottome's process for producing refined- 

 copper castings, having all the properties of 

 tough fibrous copper of high specific gravity 

 and free from blowholes or other defects inher- 

 ent in ordinary cast copper, depends on the in- 

 troduction of metallic sodium or other alkali 

 metal into molten copper. By this the dissolved 

 gases are eliminated, and the copper has a cer- 

 tain degree of hardness imparted to it. 



Alloys. Manganine is the name of a new 

 alloy, consisting of copper, -nickel, and manga- 



