358 



METALLURGY. (ALLOYS.) 



products. The solvents mainly employed are sul- 

 phuric acid, hydrochloric acid, ammonia, ammo- 

 nium carbonate, magnesium chloride, calcium 

 chloride, carnallite, etc. 



The electrolytic method is attended by obsta- 

 cles that have so far not been surmounted. Among 

 them are the enormous amount of power required 

 and the difficulty of producing compact zinc. This 

 method promises better for treating alloys, and is 

 said to be carried out in a secret process at Aaron 

 Hirsch's works at Inselberg in the Harz; and it 

 has been applied to zinciferous pyrites, which, after 

 treatment for the production of sulphuric acid, are 

 intended for use as iron ore. 



Mr. H. Van F. Furman, in a paper on zinc and 

 its treatment, after remarking that extraction by 

 electrolysis of molten compounds has not so far 

 been attempted on a commercial scale, although 

 numerous methods for accomplishing it have been 

 proposed, says that most of the zinc as it comes 

 from the adapters is sufficiently pure after skim- 

 ming in the ladles to cast into bars ready for the 

 market. Such scrap metal as is produced and any 

 zinc which contains too high a percentage of lead 

 is remelted with stirring, and then allowed to 

 settle, wnen the lead collects at the bottom of 

 the kettle. 



In some places zinc ores are treated for the 

 production of marketable zinc products, such as 

 zinc oxide (zinc white), mixtures of zinc oxide, 

 lead oxide, and lead sulphate (pigment), or zinc 

 sulphate (zinc vitriol). For these processes ores 

 are selected which are not generally suitable for 

 the extraction of metallic zinc, either because they 

 contain other valuable or detrimental qualities or 

 because the percentage of zinc in them is too small. 

 The production of zinc white from the New Jersey 

 (franklinite) ores has been brought to a high 

 state of perfection by the earlier inventions of 

 Samuel C. Wetherill and the later ones of his 

 son, J. P. Wetherill. The ores, which are mixtures 

 of franklinite, willemite, zincite, and a calcite 

 gangue containing various minerals and silicates, 

 are passed over Wetherill magnetic separators, and 

 a fairly clean franklinite and a mixed or middle 

 product of franklinite and various iron and man- 

 ganese silicates are obtained. The tailings from 

 the separators pass to wet jugs,when the willemite 

 and the zincite are removed from the silicate. 

 The concentrates from the Wetherill machines 

 are sent to the zinc-oxide works, and the concen- 

 trates from the jugs (principally willemite), which 

 carry about 50 per cent, of zinc, are sent to Ger- 

 many for distillation into a very pure spelter. The 

 residues from the treatment of the franklinite in 

 Wetherill furnaces after collection of the zinc oxide 

 in bags, gathered from the pipes and other parts 

 of the furnace, contain from 1.2 to 6 per cent, 

 of zinc, and as they are rich in iron and man- 

 ganese, they are smelted in blast furnaces for 

 spiegeleisen. 



In the Bartlett process in use at Cafion City, 

 Col., ores containing 20 per cent, of zinc, after 

 being crushed, are mixed with pea coal and dust 

 coal and blown up in a blast furnace to drive off 

 the lead and the greater part of the zinc and sul- 

 phur. A cinder is formed containing the silver, 

 gold, and copper in a matte mixed with more or 

 less slag. This cinder is smelted in an inclined low 

 blast furnace with suitable ores to produce a high- 

 grade matte. The zinc in this charge may re"ach 

 from 15 to 20 per cent., and is mostly driven 

 off as fume. The fume from the " blowing up " 

 furnace and from the blast furnace is caught in 

 bags, mixed and refined in a suitable furnace, 

 whereby carbon, arsenic, sulphur, and other im- 

 purities are eliminated and a pure white pigment 



is produced, suitable after being ground in oil to 

 be used as a white-lead substitute. 



Alloys. Experiments have been made by Ser- 

 gius Kern with a number of nickel-bronze alloys, 

 with a view to the production of castings suitable 

 to be used in mechanical work, especially for dif- 

 ferent fittings in high-pressure marine boilers. 

 The alloys rusted very slightly, and in several 

 cases proved preferable to steel castings. The 

 nickel castings from the alloys designated as 

 No. 1 and No. 2 especially gave very good re- 

 sults when mechanically tested. Alloy No. 1, 

 having the composition copper 70 per cent., nickel 

 17.5 per cent., and zinc 12.5 per cent., corresponds 

 to the rules prescribed by the English Admiralty 

 for shipbuilding steel. In the cast state it gave a 

 tensile strength of 26 tons and 23 per cent, elonga- 

 tion in 2 inches; fracture fibrous; and to the 

 bending test, 67 over a radius of If inch. Alloy 

 No. 2, having a composition of copper 70 per cent., 

 nickel 20 per cent., and zinc 10 per cent., corre- 

 sponds to the English Admiralty rules for steel 

 castings. It has a tensile strength of from 28 to 

 35 tons per square inch and an elongation of 15 

 per cent, in a length of 2 inches. Its fracture is 

 fibrous, and its response to the test for bending 

 strength gave from 35 to 40 over a radius of Ijj 

 inch. The drop tests were likewise satisfactory. 

 Both alloys were prepared in the same manner, 

 using ordinary copper crucible furnaces. Nickel 

 in the form of cubes was placed upon the bottom 

 of the crucible, next to it copper-zinc alloy, and 

 on the latter some copper, and proceeding in the 

 same way till the crucible was filled. On the top 

 of the charge a layer of charcoal was placed. The 

 alloy was run into flat open molds, and the slabs 

 obtained were remelted twice before being used for 

 castings. At each melting about 0.75 per cent, of 

 zinc was added to the melted alloy when the cru- 

 cible was out of the furnace and ready to be poured 

 through the molds. The molding was done in 

 exactly the same way as regards the sand as in 

 the casting of copper articles, but, as the alloys 

 have a notable shrinkage in setting down, top ends 

 must be placed on the castings, as is done with 

 steel castings. After pouring the metal, the open 

 top ends must be immediately covered with coarse- 

 ly ground charcoal. 



Magnalium is a silver-white alloy, composed of 

 aluminum and magnesium. It is unaffected by air 

 and water. It even withstands oxygen to a great 

 extent, though alkalies attack it. Its specific 

 gravity ranges from 2 to 2.2, and its melting 

 point lies between 600 and 700 C. It " works " 

 remarkably well, and can be rolled into sheets or 

 drawn into wire. Although other alloys may be 

 formed, that used contains 100 parts of aluminum 

 and from 10 to 15 parts of magnesium. Accord- 

 ing to Mach, the value of the alloy depends on 

 the purity of the metals; and so long as alumi- 

 num was made by reduction with sodium it \VMS 

 impossible to obtain a good alloy. The reflect he 

 power is very high indeed, and, unlike most specu- 

 lum compositions, magnalium does not absorb the 

 ultra-violet. These properties, together with it* 

 low density and rigidity, make it almost an ideal 

 composition for specula. 



Attention is called in the Engineering and Min- 

 ing .Journal to the remarkable malleability and 

 ductility of alloys containing vanadium. An ad- 

 dition of 0.5 per cent, of vanadium to ordinary 

 malleable iron of about 24 J tons tenacity and 10 

 per cent, elongation gave 39 tons tenacity and 12 

 per cent, elongation in the forged bar. and 33.7 

 tons tenacity and 32 per cent, elongation after 

 annealing. A mild steel of 30 tons tenacity and 17 

 per cent, elongation gave, with 1 per cent, of vana- 



