432 



METALLURGY. 



perforating iron plates, etc., and for the reduction 

 of metals from their oxides. Among the metals 

 that have been obtained in this manner are chro- 

 mium, magnesium, iron, titanium, barium, wolfram, 

 molybdenum, nickel, cobalt, and vanadium. Alloys 

 of barium with lead and with iron, ferrotitanium, 

 and other alloys have also been made. 



Among the various practicable applications of 

 this reducing action of aluminum, Mr. A. E. Hunt, 

 of the Pittsburg Reduction Company, mentions its 

 employment in the production of steel castings; from 

 2 to 5 ounces of aluminum per ton suffice to remove 

 oxygen from the steel, and so to obviate to a great 

 extent the formation of blow holes in the castings. 

 A little aluminum added from time to time to the 

 baths of molten zinc used in galvanizing removes 

 the oxide and keeps the baths fluid. The addition 

 of a little aluminum in making brass castings in- 

 creases their soundness in a similar way. Alumi- 

 num is used instead of brass for a multitude of 

 small and stamped objects that do not require to 

 be soldered, while no trustworthy method of per- 

 manently soldering it seems to have been found yet. 

 It may probably be used as a conductor of elec- 

 tricity, though at present the advantage in price 

 lies with copper. 



A hand car built by a St. Louis company as a 

 specimen has the wheels, body, and walking beam 

 made of an aluminum alloy of great strength and 

 lightness, and the axles of steel tubing. By means 

 of these and other improvements such as gearing 

 of the bicycle pattern admitting of adjustments for 

 the speed desired, ball bearings, and hub brakes 

 it is believed that two men will be easily able to 

 run the car for a limited time at a speed of from 20 

 to 35 miles an hour. The new car will weigh not 

 more than 150 pounds, or about one third as much 

 as the ordinary hand car, and one man will be able 

 to lift it on or off the track. 



An experiment in the use of aluminum for horse- 

 shoes has been tried in the Finland Dragoons of the 

 Russian army. One foot of the horse is shod with 

 aluminum and the other three feet with ordinary 

 shoes. The aluminum shoe has 2 ounces in weight 

 to its credit, is not more costly, and wears longer 

 than the ordinary shos, while it is not so easily 

 affected by mud and moisture. 



In one of the electrical installations at Niagara 

 Falls aluminum is used, in place of copper, for the 

 conductors connecting the dynamos at the bottom 

 of the shaft with the plant on top of the cliff. 

 According to a description in the " Western Elec- 

 trician," the bars used are 25 feet long and half an 

 inch thick, four being used in parallel, bolted and 

 riveted together every 25 feet. At the top they are 

 connected with aluminum cables U inch in diam- 

 eter, and covered with india-rubber insulation. The 

 total weight of these aluminum conductors is about 

 22,000 pounds, while the same work would require 

 48.000 pounds of copper. 



Copper and Nickel. In the electrolytic process 

 for purifying and refining copper, as described by 

 Dr. Thomas Ewan, the copper containing from 0.3 

 to 2 per cent., or sometimes more, impurity is cast 

 into plates, which are suspended, about 3or4 inches 

 apart, in large lead-lined wooden boxes. Between 

 each pair of plates a thin sheet of pure copper issus- 

 pendcd, and the solution, containing from 15 to 20 

 per cent, of crystallized copper sulphate and from 5 

 to 6 per cent, of sulphuric acid, is run in. The im- 

 pure copper plates form the soluble anode, and the 

 thin sheets receive the pure copper. The electrical 

 energy needed to carry out the process is from 0.1 to 

 0.2 electrical horse power per hour per pound of cop- 

 per deposited. Of the impurities in the anodes, gold, 

 silver, and part of the arsenic and antimony remain 

 undissolved, while iron, nickel, and the remainder 



of the arsenic and antimony pass into the solution. 

 The two latter metals are deposited along with the 

 copper when they are allowed to accumulate too 

 largely in the solution, especially if the amount of 

 free acid is small. The solution must therefore be 

 purified from time to time, and this forms the main 

 difficulty of the process. 



Nickel can be obtained pure by grinding up sul- 

 phide nickel ore and subjecting it to heat in an elec- 

 tric furnace. The sulphur is entirely eliminated, 

 and the nickel is separated from the iron. Copper 

 also has been separated from a matte of copper, 

 nickel, and iron when smelted electrically. The 

 furnace consists of cast-iron drums 10 feet in diam- 

 eter and 2 feet long, mounted on a shaft and slowly 

 rotated by a hand worm-gear ; the electrodes are 

 carbons 4 feet long and 4 inches square. The 2 elec- 

 trodes of 4 pencils each are separated by a space of 

 8 inches, the axis being the axis of the furnaces. 

 As the ore is reduced the resultant metal lowers the 

 resistance of the furnace, and when the latter is 

 slowly rotated the metal is drawn away from the 

 electrodes, and fresh ore is brought between them 

 to be acted upon. Notwithstanding the height of 

 the temperature reached, it is under complete con- 

 trol. 



Dr. Thomas Ewan says, in a paper on " The In- 

 dustrial Applications of Electro-chemistry," that 

 while it is perfectly easy to deposit a very thin film 

 of nickel by electrolysis, the metal peels off if a 

 thicker deposit is attempted. According to Foerster, 

 however, tough, homogeneous plates of nickel of any 

 thickness may be deposited from aqueous solutions 

 of the sulphate or chloride if they are heated to 

 from 50 to 90 C. The nickel, however, is not so 

 pure as copper similarly obtained, cobalt and iron 

 occurring in the refined metal in about the same 

 quantities as in the unrefined. Electrotype nickel 

 is now a commercial article; part of it is obtained 

 from alloys of copper and nickel containing a con- 

 siderable amount of sulphur, which are used as 

 anodes, the copper being first deposited, while the 

 nickel goes into solution, from which it is subse- 

 quently deposited. 



Tin and Zinc. For the electrolytic removal of 

 tin from tin plate, the tinned scrap is suspended in 

 iron baskets which form the anode, and the tin is 

 deposited in the spongy form on sheet-iron cathodes, 

 the electrolyte being a solution containing from 10 

 to 15 per cent, of sodium chloride, to which a little 

 caustic soda is added from time to time to prevent 

 the precipitation of stannous oxide. The solution 

 is warmed to 40 or 50 C., and since tin dissolves 

 under these circumstances independently of the 

 electric current, it is necessary occasionally to evap- 

 orate the solution and work up the residue for so- 

 dium stannate. 



At the Crefeld silk factory, Rhenish Prussia, is a 

 plant for recovering tin from tin-plate scrap. In 

 order to make white and colored silk heavier and 

 more agreeable to the touch, it is boiled in a solu- 

 tion of chloride of tin. The pure chloride, which, 

 of course, is most suitable for the process, being too 

 expensive, tin-plate scrap is used for the chemical 

 manufacture of a chloride. The tin is recovered 

 from the scrap electrolytically. and the impure tin 

 thus obtained is worked up further to chloride of 

 tin. 



The history of the electro-metallurgy of zinc is 

 pronounced by Dr. Thomas Ewan mainly a record 

 of failures. When deposited from neutral or 

 slightly acid solutions, zinc is very prone to sepa- 

 rate in a spongy form, probably by the formation 

 of traces of oxide. This maybe remedied by the 

 presence of reducing agents or by vigorous circula- 

 tion of the solution, and is promoted by the pres- 

 ence of metals more electro-negative than zinc, 



