388 



METALLURGY. (COPPER, ZINC, NICKEL ALLOYS FUELS.) 



In the Gelshart process for the electrical sepa- 

 ration of pure tin from waste fin cuttings, the 

 tin is recovered by electrolysis, and the cleansed 

 iron is sold as best scrap or is converted into 

 green copperas, which may be further converted 

 into red oxid or Nordhausen sulfuric acid. The 

 electrolyte in the stripping tanks is a l|-per-cent. 

 solution of commercial hydrochloric acid, to 

 which is added a small quantity of oil of vitriol. 

 Copper, Zinc, Nickel. In poling copper 

 Mr. E. S. Sperry leaves the reduction of cuprous 

 oxid uncompleted, in order that the traces of bis- 

 muth, arsenic, and antimony in the copper remain- 

 ing shall be present as oxids, where they are less 

 harmful than as metals. Small amounts of cu- 

 prous oxid are liable to make copper somewhat 

 cold-short, but not hot*short; hence the metal is 

 rough rolled hot and finished cold. In making 

 brass, some of the zinc is oxidized at the expense 

 of the metallic oxids contained in the copper. 

 In experiments made to see what effect the oxy- 

 gen of the copper had in brass-making the copper 

 used was oxidized by exposing it in a melted 

 condition to the air. Analysis gave from 1.2 to 

 1.52 per cent, of oxygen. Oxidation with niter 

 proved unsuccessful. The base composition of 

 the brass used was copper 60 per cent, and zinc 

 40 per cent. The experiments showed that the 

 amounts of oxygen usually contained in econom- 

 ical copper (from 0.010 to 0.012 per cent.) have 

 no harmful effect on the quality of brass intend- 

 ed for rolling into sheets; the oxygen may reach 

 even 0.55 per cent, and do no harm if specific 

 care be taken. An excessive amount of oxygen 

 causes the formation of a salamander, a mixture 

 of infusible zinc oxid and copper. If oxygen is 

 present in not sufficient amount to form a sala- 

 mander, but in the proportion of about 0.55 per 

 cent., the brass will show a tendency to crack, 

 owing to the presence of zinc oxid. 



In a process for copper-matte concentration de- 

 scribed by Thofehm and St. Seine (Oesterreiche 

 Zeitschrift), a mixture of air, superheated steam, 

 and silica is blown upon a bath of molten matte 

 or crude metal in a reverberatory furnace. A 

 rapid oxidation and scorification of the metals 

 to be removed take place in the zone of action 

 of the tuyfrres without any mingling of the slag 

 with the bath, the action of the blast being 

 to drive the slag toward the skimming doors and 

 keep the bath of metal in the blast zone uncov- 

 ered. The walls and the hearth of the furnace 

 are not affected during the scorification. The 

 process is applicable to furnaces of large size. 



The dictum that barytes in zinc ores is in- 

 jurious by causing the formation of a sulfid of 

 the zinc has been contradicted by the experiments 

 of Prof. Prest and others. The evidence of these 

 experiments is confirmed by the studies of K. 

 Sander, who charged 10 retorts with 400 kilo- 

 grams of roasted blende containing lead and 9.2 

 per cent, of barytes, and another set of 10 retorts 

 with roasted blende free from barytes, The residue 

 from the former set of retorts assayed 2.70 per 

 cent., and that from the latter 3.54 per cent, 

 of zinc. In a repetition of the experiments 

 the percentages of zinc in the residues were 2.08 

 per cent, and 2.92 per cent, respectively. 



In the application of the Mond nickel process 

 to the Sudbury pyrrhotite, the ore is roasted and 

 melted to a matte containing about 20 per cent, 

 of nickel. This is Bessemerized to a product con- 

 taining 18.62 per cent, of copper, 31.37 per cent, 

 of nickel, and 0.7 per cent, of iron. The matte 

 thus concentrated is dead roasted and treated 

 with dilute sulfuric acid, whereby about two- 

 thirds of the copper and from 1 to* 2 per cent, of 



the nickel are extracted. The residue after dry- 

 ing assays from 40 to 60 per cent, of nickel. It 

 is treated in charges of 500 kilograms with water- 

 gas in a reduction-tower at a temperature of not 

 more than 300 C. The tower is fitted with 14 

 hollow shelves heated to 250 C., on which the 

 material is raked from one to another to the 

 lowest shelves, which are cooled. The reduced 

 copper is then transferred to another similar 

 tower called the volatilizer, in which the metal 

 is treated w r ith carbon monoxid at a temperature 

 not exceeding 100 C. The residue from the 

 volatilizing tower goes back to the reducing 

 tower, and the charge is thus passed back and 

 forth from tower to tower for from eight to fif- 

 teen days. When 60 per cent, of the nickel has 

 been volatilized as carbonyl, the residue is re- 

 turned to the roasting furnace. The nickel car- 

 bonyl is treated in the decomposing apparatus, in 

 which the nickel is recovered as granules of from 

 99.4 to 99.8 per cent, purity. 



Alloys. The Committee on Alloys reported to 

 the British Association that the research for 

 which it was formed had been completed, and a 

 summary of the results had been published in the 

 Proceedings of the Royal Society. The work con- 

 sisted in a study of the chemical compounds and 

 solid substances to be found in alloys composed 

 of copper and tin. The report shows that at least 

 three series of solid solutions are formed during 

 the solidification of these alloys. The first series, 

 which may be called Alpha, consists of crystals 

 isomorphous with pure copper and varying in 

 composition from pure copper to an alloy con- 

 taining about 9 per cent, by weight of tin. These 

 alloys solidify to a uniform mass, and apparently 

 remain unchanged at all lower temperatures. The 

 second series, which may be called Beta, contains 

 percentages of tin varying from 22.5 to 32. Alloys 

 containing between 9 per cent, and 22.5 per cent, 

 of tin solidify as a complex of crystals of Alpha 

 and of Beta. But all such alloys having from 9 

 per cent, to 32 per cent, of tin undergo impor- 

 tant recrystallizations after they have wholly 

 solidified, and their final condition below 500 C. 

 is that of a complex of Alpha and of a crystalline 

 body which is probably Cu 4 Sn. Alloys from 32 

 per cent, of tin to 52 per cent, begin to solidify 

 by the formation of a third type of crystalline 

 solid substance, which may be called Gamma. 

 But the Gamma crystals break up at lower tem- 

 peratures into a complex of crystals of the body 

 Cu s Sn and another substance. The alloy of the 

 formula Cu s Sn is apparently a solid solution 

 when first solidified, and is not converted into 

 the compound until a lower temperature is 

 reached. Gamma crystals containing more than 

 41 per cent, of tin have the peculiarity that, in 

 cooling, they break up into solid Cu s Sn and a 

 liquid. Between 57 per cent, of tin and 43 per 

 cent., the first solid that forms when the liquid 

 alloy begins to solidify consists of CuSn; but 

 when the temperature falls to 400 C. these crys- 

 tals become unstable, and a reaction takes place 

 between them and the liquid, which results in 

 their partial transformation into a body which 

 is really a quite pure CuSn. Between 93 per cent, 

 and 99 per cent, of tin, the substance CuSn is the 

 first body formed during solidification. Between 

 99 per cent, and 100 per cent., tin appears to 

 crystallize first. The paper closes with a sum- 

 mary of the condition of the alloys at common 

 temperatures, it being assumed that they have 

 been cooled with sufficient slowness. 



Fuels. A paper on smokeless fuels read in the 

 Engineering Club of St. Louis, Mo., mentioned 

 powdered coal as promising to be the cheap- 



