The Iron Age 1902-11-20: Vol 70

ry! — & Vv ‘THB IRON AGE TuurspDay, NOvEMBER 20, 1902. The Jolly-McCormick Turbines at the « Soo.’’ The magnificent power station at the Sault Ste. Marie, which was put into commission a few weeks ago, is the largest example extant of the application and development of water power from a low head. While the preparatory work necessary to make this a success- on it showed it to be far in advance, in points of effi- ciency, power and speed, over any of the turbines then on the market. The usual method of setting turbines has been to place the wheels so as to revolve in a horizontal plane, the shafts being vertical. With the advent, however, of expansion in the electrical fields, and the applica- Pair of Turbines. Fig. 2.—View of Forebay. THE JOLLY-McCORMICK ful installation did not call forth the combined skill and efforts of hydraulic engineers in all parts of the world, as did the Niagara Falls equipment, yet it took months of experiment and study before being perfected, and as installed has at least one point of advantage over its great rival, in that the efficieucy of the turbines is far ahead of the latter. The type of turbine used in this equipment is the well-known McCormick turbine, which might well be termed the standard type in this country. When originally brought out the tests made TURBINES AT THE “S00.” tion of water power to the generating of electrical cur- rents, it became necessary to set turbine wheels in a vertical position on horizontal shafts. When the Mich- igan Lake Superior Power Company prepared their plans for the new power house this setting was finally determined on as being the most economical, and pro- posals and plans were invited from turbine builders. Up to this time all tests of wheels had been made on a vertical step at the Holyoke Water Power Company’s flume in Holyoke, Mass., which is at present the most THE IRON AGE. reliable testing station, as it was designed by Francis and constructed by Clemens Herschel. This type of flume was used by Francis to obtain his formule for ealculating water powers, which are authoritative to- day. To make tests on wheels in a horizontal setting required considerable expenditures, and an arrangement was finally entered into between the Power Company, the Webster, Camp & Lane Company, Akron, Ohio, and J. & W. Jolly, Holyoke, to design, build and test a turbine unit which should fulfill the following require- November 20, 1902 four turbines arranged in pairs, with one draft tube for each pair. Each pair is keyed to an open hearth hammered steel shaft and the two shafts are bolted together by means of forged couplings. The shafts are designed to transmit double the power of the gen- erators with the usual factors of safety. This is to pro- vide against the torsional vibrations caused by generat- ing an alternating current. Each pair of the turbines discharges into a central conical ended draft case, and the discharge is continued to the tail race by means of ay was, ||) a | | he ” 4 ee eer | CIRCULAR STEEL BULKHEAD || WITH RADIUS OF 7 FT. 3” STEEL PLATE 14" THICK | 875- KILOWATT WESTINGHOUSE ALTERNATOR Sika Sed So PaO ? oay Fee aret ey eeeeeh wo Portes a gee sess Fbge SO SOST CI SRST e d _— Pe Cree rerss SoS. SOO" oO one pd SOE SM FOREBAY WALL CONCRETE BLOCKS TAILRACE PIT Tosa D a os ape PSS WO"G 4 Fig. 4.—Elevation and Section of One Pair of Turbines. THE JOLLY-McCORMICK TURBINES AT THE “800.” hr ments: With a 16-foot head the unit must develop 568 horse-power at 180 revolutions, with an efficiency of 80 per cent., tests to be made at Holyoke under the super- vision of Prof. G. 8S. Williams of Cornell University. After many months of experimenting with improved forms of wheels and various designs of draft cases and draft tubes, the final design, as illustrated by Fig. 1, was adopted. The best results finally obtained were as follows: Head, 16 feet; speed, 180‘ revolutions per minute; horse-power, 584; efficiency, 84 per cent. These figures speak for themselves. The penstock unit, as shown in Fig. 4, a conical steel plate draft tube. The draft cases are made of cast iron and are separable in a horizontal plane parallel with the turbine shafts, making them easy of access. The center of each case is provided with a yoke or steady rest for the turbine shaft. The combined water wheel shaft is supported by three heavy cast iron pedestal girders that rest on the side or foundation walls of the penstock. The water bearings are amply large and are made from specially prepared wood blocks. These are backed with iron and can be adjusted for wear. The draft cases are supported by heavy spanning frames made from 15-inch steel I-beams. These also Bee > hy Se consists of a ee en a ee + PIES ETI GS RE a Te ok ee Ry oy ee ware. seme i ’ ga 2 Pet AA renee: WeveF THE November 20, 1902 rest on the side wall of penstock. This construction frees the arches over the tail race from the weight of the machinery. The draft case and pedestal girders are tied together on each side by longitudinal bars, making a substantial and ideal support for the running parts The turbine shaft penetrates the curved bulkhead by means of a stuffing box properly secured to the steel plates by rivets. The common horizontal gate shaft extends through the bulkhead into the dynamo room in like manner, and is provided with the necessary rig ging to manipulate the gates of the four turbines simul taneously by hand or by machinery. The turbine shaft at the end furthest from the dyna mo room is 514 inches in diameter and increases in size until it is 74 inches in diameter at the dynamo end, and is arranged to be coupled to the horizontal dynamo. Each of the four turbines is incased in a balance gate curb, while the individual gates are so poised as to di- rect the flowing water properly, and differently, at the Fig. 5.—Cross Section of Turbine. IRON AGE. 3 patterns have remained in the owners, in Holyoke, Mass. MeCormick that a log could be drawn more readily through butt first, requiring less power than if drawn top first. He learned that a stream or jet of water had its highest velocity in its center when not acted upon by other forces, and he was the first to recognize this in constructing and patenting a turbine bucket. He learned that whirls, eddies and cross currents recklessly ignore any formule that are usualy developed for their guidance; he also learned that a pattern perfect in shape for one size of runner could the shops of original learned water — ar iE tan i ae Ny : f es a a Fig. 6.—Erecting a Turbine in Penstock. Fig. 7.—View of Turbine. THB JOLLY-McCORMICK different degrees of gate opening, maintaining a high efficiency at part gate. History of the Jolly-McCormick Turbine. In the progress of any science or art, usually some one name becomes associated with its development that lends to it a stamp of genuineness in the public mind that no other name can impart. This is just as true in the development of turbine water wheels as in tele- phones, engines and pumps. John B. McCormick’s name is familiar wherever first-class turbines are known. His early life as a raftsman on the Allegheny River, his preliminary work of developing several systems of tur- bines for various manufacturers, and his final develop- ment of a full series of tested patterns in the shops of J. & W. Jolly, are matters of history. The fact that he made as high as 18 sets of patterns for some of his turbines before being able to secure the desired results is not generally known; neither is it known that it took years to develop a full series of patterns, nor that these TURBINES AT Fig. 8.—View Opposite Fig. 7, Showing Buckets. THE “SOO.” in no way guide him to a pattern for a larger or smaller size. So he patiently developed his patterns one set at a time, until they would produce a turbine satisfactory to him. His work was then only half finished, as it Was necessary to make a second set of patterns for tur- bines to turn in the opposite direction. These full series of patterns, with the data pertaining to their exact posi- tions in the turbine structure, constitute the stock in trade as far as patterns go. No published formule or system of measurements exist from which a McCor- mick turbine can be made, and his private formula was, in each case, a turbine that will furnish 25 per cent. more power at a higher speed than any competitor’s turbine, and at above 80 per cent. efficiency. To incorporate this turbine into the more modern power house has developed new problems. The ques- tion of government was not of prime importance with McCormick; hence the experience of spectalists in the way of governing gates has been added to this turbine. McCormick’s were made on tests vertical steps, while 4 THE IRON AGE. modern practice is inclined toward mounting turbines on horizontal shafts, usually in pairs. This practice, while ideal in construction, has not always been satis- factory from a power point of view; in fact, some very large installations of this kind have fallen from 10 to 25 per cent. short of their proposed power. The Michigan Lake Superior Power Company were cognizant of this fact and made use of it in their selection of Jolly-Mc- Cormick turbines mounted in draft cases designed and built by the Webster, Camp & Lane Company, Akron, Ohio. There are some essential principles in draft tube construction that are overlooked in ordinary turbine building. Past experience has clearly demonstrated that vertical step turbine tests will not hold in horizontal settings, unless correct construction is used in the whole system. It might be added that it is possible, through faulty construction, to develop no power from water that has passed the turbine, while, on the other hand, the water may be made to yield power even after it has reached the lower level or tail water. (The latter statement may provoke a smile in the novice, but it will wear away with reflection.) A close inspection of the “Soo” unit will convince that some radical change has been made from common practice. ee Electric Fire Pump in Rouen. A recent report from Consul Haynes at Rouen de- scribes an electric fire pump in use in that city. It is composed cf a centrifugal pump and of an 8 horse-power motor, which gives normally 2000 revolutions per min- ute. A continuous current of 525 volts can be applied. This inotor is well covered, so as to prevent all penetra- tion of water. Above are two bobbins: On one is wound the wire upon which the current is received, the ex- tremity being exposed in such a manner as to allow con- nection with a hook suspended from the tram or elec- trie light wire; on the other bobbin is wound the return wire, the free end being connected with a cast iron block to be fastened to one of the tramway rails. There is beneath the covering a compartment containing two circuit breakers, a circuit closer and commutator. To start the apparatus it is only necessary, after con- necting the two wires to the line giving the energy, to close the circuit and start it running slowly with the rheostatic guide. The time necessary for starting is about a minute. The bobbins on which are wound the conductors can receive 656 feet of insulated wire; if to this is added the 200 meters of hos* on the reel and the 114 feet to which the water can be thrown, it is seen that a distance of 1427 feet can be covered. The distance that the water can be thrown, nearly 115 feet, is accomplished with an orifice of 0.7 inch and a volume of 92 gallons a minute. The whole machiue can be placed on a hand cart, or on a little two wheeled wagon drawn by one horse. Its total weight, with accessories and two men on the seat, is about 22¥2 pounds. The motor and pump are not longer than a meter, and about % meter wide and % meter high. Behind the machine is a reel capable of holding 984 feet of bose, two lances, a ladder with hooks, an axe, a hydrant key, a nozzle, &c. The weight of this reel, equipped, is 727 pounds. The idea of this pump, which is the only one of its kind in France, if not in the world, was suggested to M. Robert Lefebvre, the captain of the Rouen Fire Com- pany, by a conversation he had last year with a German engineer at the Berlin Fire Extinguishing Exposition. This latter had conceived the idea of an electric pump for cleaning the walls of buildings, &c. If sand thrown by an electric pump could clean buildings, why could not water thrown in the same manner extinguish fire? In the solution of this question the electric fire pump was born. aero The Engineers’ Club of Philadelphia will celebrate its twenty-fifth anniversary at a banquet at the Union League on the evening of Saturday, December 6. An in- teresting programme is being arranged for this occasion. November 20 1902 The) Rapid Determination'' of “Molybdenum in Steel. Ze BY GEORGE AUCHY, TACONY, PHILADELPHIA. For the determination of molybdenum in steel, the writer some time ago proposed the very obvious method of separating from iron by caustic soda and reducing with zine and titrating with permanganate. Since that time several improvements in carrying out the de- tails have suggested themselves, and the method now used is as follows: A blank or dummy test must be made as follows: 0.8 gram of drillings is treated with a mixture of 15 ec. em. dilute nitric acid, 10 c. cm. concentrated hydro- chloriec acid, and 3 ¢c. cm. concentrated sulphuric acid and the liquid in a covered porcelain dish boiled down over the full flame of a Bunsen burner to the appear- ance of fumes. The fumes must be very dense. The cover must afterward be removed and thoroughly dried by itself. The residue is then’ boiled up with 50 c. cm. water; allowed to cool; poured by degrees and with shaking into 100 c. cm. of a caustic soda solution made by dissolving 1 pound of soda in about 2100 c. cm. water. The 100 c. cm. of caustic soda solution is in an 8-ounce Erlenweyer flask, provided with a file mark at 200 c. em. The liquid is diluted to this mark, well mixed by shaking the flask, and allowed to stand till settled; then filtered through a dry filter into a 100 c. cm. measuring flask till the mark is reached: then acidified with 15 c. cm. strong sulphuric acid, re- duced and titrated as in phosphorus determinations. Worked in this way the method is one of the easiest and most accurate of technical analytical processes. Brakes modifies Copp’s acid sulphate fusion method by omitting the fusion and obtaining the steel in sul- phuric acid solution by evaporation to fumes. The ad- vantage of this plan over Copp’s procedure is obvious. It also has the advantage over the writer’s method that ammonia is more convenient to use than caustic soda. But there is a very serious defect connected with Brakes’ method—one that can only be remedied in part, and that only at the expense of much time—namely, the use of 1000 c. cm. of solution for separation and filtra- tion and 500 c. cm. of solution for reduction and titra- tion. Not only is the bulk of solution unwieldly to work with, but it is also inaccurate for the reason that the reduction is apt to be incomplete when made in such a large volume of solution. That this is true is proved by the fact that Brakes finds it necessary to use the old Emmerton factor in order to obtain true results. With a low percentage of molybdenum, he would, without doubt, find that even with the use of the Emmerton fac- tor results would be too low. The stability of the re duced molybdenum solution is in proportion to its con- centration. Simple dilution will instantly change the green MO,O, solution into the port wine MO,,0,, solu- tion. The obvious remedy would seem to be to make the separation in small bulk, as does the writer in the caustic soda method. But unfortunately this cannot be done, as the separation is in that case not a complete one when ammonia is used. This is shown by the following results: In these tests 25 c. cm. of solution of steel were poured into a mixture of 100 c. cm. strong ammonia and 50 c. cm. water; diluted to 200 c. cm., filtered, and 100 ec. cm. taken for reduction and titration, after boiling off excess of ammonia. Results by the caustic soda method described in this article are also given. , Ammonia meth- od.—Separation Ammonia meth-_ in large bulk, Caustic od.—Separation reductionand soda method in small bulk of titration in small ag above de- solution.—Molyb- bulk.—Molyb- scribed.—Molyb- denum found. denum found. denum found. Per cent. Per cent, Per cent. 8.90 10.00 9.90 8.80 9.80 9.90 8.80 9.70 9.80 8.50 era 9.90 8.90 9.80 ‘cers 9.90 5.00 Molyb- denum present. Per cent. 9.90 9.90 9.90 9.90 9.90 9.90 4.95 oo Re SOOO seellae—‘a‘CséCSP od . = ee A ed ‘Ss Se ty <e VW GS ee November 20, 1902 The Electric Smelting of Iron Ore. BY A. J. ROSSI, NEW YORK. Electro-metallurgy has already taken such a promi- nent place in the manufacture of many chemical or metallurgical products and in the separation of metals or the production of their alloys that it was but natural that the thoughts of engineers should have been directed to the electric smelting of iron ore to obtain pig iron and, as some claim to or have done, even steel. Numerous patents bearing almost exclusively on special arrange- ment of the furnaces have been secured. Some have been experimented with, and to a certain extent suc- cessfully. The most sanguine have gone so far as to predict a sort of revolution in the iron industry in the near future (on a small scale); others, more skeptical, have unhesitatingly foreshadowed a dismal failure, on the score of economy if nothing else, when the electric process is to compete with the much abused blast fur- nace. We will class ourselves among the “ opportunists ” and those, more reserved, who consider that the question is well worth an impartial discussion either as to its possibility or as to the limits of successful operation. As is often the case in such matters, experts do not agree. It seems to us that the advocates of both sys- tems have gone too far. We propose in the following to set forth what we think could legitimately be expected from this electric smelting of pig iron, at least in the present state of the arts, basing our deductions on an examination of what has been published on the sub- ject, choosing only the more authentic and reliable cases as based on sound scientific discussion, and stating the results obtained by ourselves, not experimentally, but on a scale sufficiently important to be called industrial, since we smelted iron ores for pig iron, as a sort of incident of other manufactures, day and night in a continuous manner for weeks at the rate of about 1 ton or over per day. Questions Involved. The question of electric smelting may be considered under the following points: 1. Is it possible to treat directly in any electric fur- nace iron ores, magnetites, hematites or carbonates, so as to obtain from them cast iron, in a practical if not an economical manner? All metallurgists, we believe, will answer yes on this point without hesitation. It does not require discussion. It has been done by many and we have done it ourselves. o 2. The possibility of this electric treatment once ad- mitted, is the product obtained of as good quality as the one obtained from the smelting of the same ores in the blast furnace? On this score also the answer may be considered as affirmative. As far as we are person- ally concerned, we indorse this view without reserve, the price at which one can dispose of an article being for us, and as it will be admitted by all, a good criterion of its value. 8. Can the economy of such electric treatment of iron ores be compared to that of the blast furnace process and can it be of as extensive application as the latter? This is the fundamental part of the question. Arguments in Favor of Electric Smelting. In experiments carried out in Germany a few years ago with the process known as the “‘ Taussig Process,” the inventor claimed that pig iron could be manufac- tured with a plant equipped with 500 to 600 horse- power, using good iron ores containing 48 to 50 per cent. iron, at a cost of $9.65 per ton, assuming the price of ore to be $2.40 per ton, and that this price could even be very materially lessened with a large plant when operating with an electric power not less than 1000 horse-power. All this estimate is based on experiments made on a very small scale, with a power of about 20 horse-power. At the price at which pig iron was sold at the time (1894), assuming even the cost of electric smelting per ton to have been really what the inventor stated or hoped for, there was not much margin for THE IRON AGE. 5 profit, if any, but, for that matter, there was not much profit in the case of blast furnace smelting. The pig iron obtained electrically proved to be of excellent quality, tests made of it at the Royal School of Mines of Berlin having given such results as 3410 kg. tensile strength for a round bar 10 mm. (0.39 inch) in diameter, which corresponds to 28,560 pounds tensile strength per square inch. A report on these experi- ments and tests having been made to the Department of State at Washington by Frank H. Mason, Consul- General of the United States at Frankfort, they seem authentic and for this reason we have quoted them.* More recently, in an article on the same subect, which appeared in 1901 in a French publication, “The Echodes Mines et de Metallurgie,”+ the statement is made that three electric furnaces, of 500 electrical horse-power each, have been erected in the valley of Canonica in Southern Italy (were to be is probably more correct), for the manufacture of pig iron under the Stassano,patent, which bears, like the preceding, on some of the arrangements of the furnaces. The conclusions of the article are that in order to ob- tain a metric ton (1000 kg., or say 1 gross ton of 2240 pounds) of pig iron per hour 3000 horse-power are re- quired, the cost of the horse-power being 18 francs, or say $3.50, per gross ton of pig metal per hour, or 24 tons per day. If we take this figure, 3000 horse-power hours per gross ton, it gives 1 pound of pig iron per hour for each 1.33 horse-power expended, or 0.75 pound of pig iron per horse-power hour. Details of the Stassano process have appeared in sundry technical publications abroad and have been more or less reproduced in the scientific press of this country. Leaving aside all questions relating to the peculiar construction of the furnaces as not germane to our subject, at least direct- ly, we may retain from these descriptions the following: Calculations of the amount of heat necessary for the reduction of the ores, the fusion of metal and slag, &c., are taken to give 2000 calories per kilogram, equivalent to 3600 thermal units per pound of metal smelted; that in fact, based on an experiment made with 100 horse- power, 2780 horse-power should prove sufficient per metric ton hour, so that 3000 horse-power is ample for the purpose. It appears indeed from an actual test which, it is said, was made of the process in an experi- mental furnace of 100 horse-power, the energy being supplied by two dynamos of 300 horse-power each at a potential of 50 to 60 volts, that, the furnace having been preheated by passing the current through for 20 minutes before introducing the charge, there were ob- tained 8 kg. of pig iron in 35 minutes, at an expense of energy of 2.70 horse-power per kilogram, which corre- sponds to 1.23 horse-power per pound hour, or2780 horse- power per gross ton day, assuming 1 kg. equals 2.204 pounds. We might quote many other examples of tentative electric smelting, but the above will suffice for our present purpose, as establishing beyond contest, at least, the first three following points: 1. That pig iron can be smelted from ores in an electric furnace. 2. That the quality of the product is fully as good as that of the best pig iron obtained in the blast fur- nace, 3. That an electric horse-power could certainly be obtained at a cost of $3.50 hour for 3000 horse-power; that is, of $0.08744 per horse-power day, or $13.40 per year. 4. As a mere estimate, based on a test of one hour in special conditions, that such a favorable figure as 3000 horse-power per gross ton hour was considered as sufficient, which corresponds to 0.75 pound of metal per horse-power hour, or 1 pound of pig iron for 1.33 horse- power hour. The calculations from which these deduc- tions were made do not appear to us to have been made on a very sound basis, nor the practical conclusion ar- rived at sufficiently justified by a test of one hour in * Communication by Frank H. Mason, Consul-General United States at Frankfort to the Department of State, April 26, 1894 +’ Echodes Mines and Metallurgie.”” Reproduced in part by ey tg Mining Journal, October, 1901, Vol. TXXIL o. 16, p. ; ey aL ET Te ae =r we mh, i a , co Siete is cL ~ caer e | Fs _ SEC SID | a NTR. 1 7 et ees ee EY FLEET SET EE GD LM IRE A SRR pc RO ep mee ae % ru 4“ es a Loe 6 THE IRON AGE. the circumstances mentioned. But, such as they are, these figures can form the basis of the discussion which is to follow and for this reason we will retain them. Arguments Against Electric Smelting. In an article which appeared in 1901 in The Engineering News there is an_ elaborate’ discus- sion of the subject on a more scientific basis and pre- senting the question in its proper aspect. Although we take exception to the sweeping conclusions of the au- thor, we do so not on account of the figures that he gives and which are certainly too low and more than conservative, but because they cover only a part of the elements which enter into the making of the cost of manufacturing iron and have a bearing on the com- parative cost of the product as obtained by the two different processes, blast furnace and electric smelting. Broadly stated, the author correctly claims that, in order to decompose the oxides of iron of an iron ore, impregnate the metals with such other elements, car- bon, silicon, sulphur, &c., as enter in its composi- tion, and such other items as are well known to metallurgists, it is necessary to generate and supply a certain amount of heat; that heat and power being in- terchangeable, this amount of heat corresponds to a certain amount of horse-power or mechanical energy in a given time and that it is immaterial if this heat ap- pears as fuel burnt in the blast furnace or electric en- ergy developed, all of which statements are irrefutable. He states that in order to reduce 1 pound of iron from its oxides it is necessary to supply 3396 thermal units and to make pig iron, with such contingencies as have been mentioned broadly, 4000 thermal units per pound of pig metal, or per ton of 2000 pounds 8,000,000 thermal units. One horse-power being equal to 33,000 foot pounds per minute, or to 1,980,000 foot pounds per hour, equals 47,250,000 foot pounds per day. This, divided by 778 foot pounds per thermal unit (figure which he adopts as the mechanical equivalent of 1 thermal unit), corresponds to 61,080 thermal! units per horse-power day. Since we have to supply 8,000,000 thermal units in order to make 1 ton of pig iron (2000 pounds) a day, we want 131 horse-power. This is equivalent to 3144 horse-power per ton of 2000 pounds hour, or 3521 horse-power per,gross ton of pig iron hour, instead of the figure 3000 horse- power, mentioned and estimated in the Stassano process and this, he adds with perfect right, supposing the fur- nace to work theoretically perfect; that in fact, we may add, the ore would yield ail that it can theoretically produce of metal without losses of any kind. In good modern practice 1 ton of coke per ton of pig iron is considered a very satisfactory figure. At $2.50 a ton this makes for fuel per ton of pig iron by the blast furnace process an expense of $2.50. In the electric furnace the corresponding energy, 131 horse- power a day, at $20 a year per horse-power, a figure con- sidered by the author to be a minimum, corresponds to $0.0548 per horse-power day, or to a daily expense electrically of $7.29 per ton. Hence, concludes the au- thor: “Even if a process of electric iron smelting could be developed, operating nearly theoretically per- fect, it would be only a laboratory curiosity, since its cost of operation under the most favorable circum- stances would be several times as great as the cost of the present methods of reduction by the combustion of fuel in the blast furnace.” Yes, if the cost of fuel as compared to that of the electric energy were to be the only element of economy of such calculation, and even so if the cost of the electrical horse-power is $20 a year. But were the horse-power to be worth only $2.50 a year there would be equality between the two methods of smelting work- ing under the same conditions and leaving out all other items entering in the final cost and not considered by the author. Discussion. The elements of heat expended qr to be supplied in the blast furnace may be enumerated as follows: Reduction of the oxides of iron of the ore, also of a part of the silica, alkali metals, sulphur, phosphorus, of November 20, 1902 which the radicals enter into the composition of th: product. Fusion of the pig metal. Fusion of the slag. Losses in the gases escaping at the top and only partly utilized for heating the blast. Vaporization of the moisture of ores, fuel and fluxes. Decomposition of the carbonates of the ores (if any) and in all cases of the limestone used as flux. Vaporization of the moisture of the air blown in through the tuyeres. Cooling by the tuyeres. Losses by radiation. Some of these items need not be considered in electric smelting and others only to a much smaller ex- tent. Many of them depend on the composition of the ores in each case. With such ores as would be con- templated to be smelted electrically, the amount of slag may widely differ. It is clear also that such loss of heat as is carried away by the tuyeres or the volatili- zation of the moisture of the blast in the blast furnace need not be considered in the electric furnace; incident- ally the amount of carbonate of limestone to decom- pose is smaller in an electric furnace by all the quan- tity required for the ashes of the fuel, or at least two- thirds of it. The heat carried away by the gases es- caping at the top of the blast furnace is another im- portant item of loss which does not exist to the same extent, if at all, in the electric furnace, the carbon re- quired being only such as is necessary for the reduction of the oxide of iron and not being more than one-quarter to one-third of the quantity which figure in the charges of the blast furnace, assuming in the latter only 1 ton of fuel per ton of iron; no air is purposely intro- duced in the electric furnace, still less blown in with its moisture to be vaporized. We find in Ledebur’s “ Metallurgy ” that the heat ex- pended per kilogram of white pig smelted in the char- coal furnace of Voldenberg, the blast being heated to 300 degrees C., and blown in at the rate of 215.20c. m. per kilogram of pig iron, the furnace producing 15 tons a day, amounted, by calculation, to 2726 calories per kilogram, or 4907 thermal units per pound. The heat strictly required for the reduction of oxides, fusion of metal and slag figuring at 2382 calories; that carried by the gases at top to about 188, and that carried away by the vaporization of the moisture of the blast and losses at the tuyeres to about 6 per cent. of the whole 2726 calories. If we omit the latter as strictly peculiar to the working of the blast furnace we come to 2680 calories per kilogram, equivalent to 4680 thermal units per pound, or some 17 per cent. more than the 4000 thermal units assumed by the writer of the article al- luded to. The calculations of Ledebur show, by the other side of the balance sheet, that some 93 to 95 per cent. of the heat supplied was accounted for in this case. Expressed in another form for comparison with the electric process, the yield was only 93 per cent. of what it might have been theoretically, had all the heat proved effective. On the other hand, in the Ormsby furnace, running on gray iron, capacity 584 c. m., production 63 tons per day, blast at 780 degrees C., gases at 412 degrees, ores 40 per cent. of iron, Ledebur calculates that 3887 cal- ories per kilogram, equivalent to 6990 thermal units per pound of cast iron, were required, instead of 2726 calo- ries in the Voldenberg furnace. This figure repre- sented only 87 per cent. of the total heat (4448 calories) as calculated by Ledebur on the debt side of the balance sheet, which, for our purpose of comparison of the two methods, may be expressed by saying that the yield was only 87 per cent. of what the heat supplied could have theoretically yielded. In other words, this balance of heat in a blast furnace cannot be assumed @ priori for the purpose of comparison, it may vary widely with the composition of the materials entering the charge. The physical state of the ores has also a great deal to do with the matter; ores absolutely unfit for blast furnace use on this score are, on the contrary, eminently wel! adapted for the electric furnace. Assuming, from Ledebur and other metallurgists, 1796 ealories for the reduction of 1 kg. of oxide of iron (ferric [~~ wa Ss = F Qe a2aon FP wN emer ntr See VWF eo ‘}] D6 ‘ic November 20, 1902 THE IRON AGE. 7 yxide, Fe,O,), 1900 calories per kilogram of pig metal impregnated with silicon and other usual elements found in pig iron, 300 calories per kilogram for the fu- sion of 1 kg. of gray pig, 375 calories for the decompo- sition of 1 kg. of average carbonate used as fluxes and also present in the ores in some cases, and that 1 calorie equals 4 thermal units, 1 kg. equals 2.204 pounds, 1 horse-power equals 640 calories equals 2560 thermal units, let us make the calculation similar to that quoted from Ledebur of the heat which, theoretically, would have to be expended for the reduction of an iron ore such as the one we have smelted electrically for weeks n succession, omitting, however, in the estimate such tems as refer essentially to the peculiarities and re- juirements of blast furnace working as previously ob- erved. This ore, on an average, contained 57 per cent. of iron, which corresponds to 80 per cent. ferric oxide, so that there were 20 per cent. of gangue to go to slag. To 100 kg. of this ore were added, as flux, 15 kg. of limestone containing about 7 kg. of lime, magnesia, &e., so that the slag could be expected to amount to 20+ 7=27 kg., and the carbonates to decompose to 15 kg. Now, 57 kg. of iron in ore corresponds to about 60 kg. of pig iron estimated to contain on an average 95 per cent. of iron, the balance being silicon, carbon, &e. We have: Calories. Reduction of 60 kg. of pig iron X 1900 calories........ 114,000 Fusion, 60 kg. pig metal 300 calories............... 18,000 Fuse, Hele, Ze Be. X DOO CRIOPIOD. occ cccccscccncoses 13.500 Decomposition, 15 kg. carbonates X 375 calories....... y PE Cevcr nae ahrs seb beets ree kuteveeetwanarees 151,125 for 60 pounds of metal, or 2520 catories per kilogram, equivalent to 4536 thermal units per pound, but this supposes that all the heat, equivalent to the mechanical energy of the current, has been effective without losses of any kind either as heat itself or as to production of metal by incomplete reduction of the ore and conse- quent loss of iron in the slag. We may remark here that if to this figure of 4536 thermal units per kilogram we add 6 per cent. as representing items peculiar to blast furnace smelting, we find 2670 calories per kilogram equivalent to 4808 thermal units per pound, as com- pared to the 4000 thermal units estimated by the writer of the article. This examination shows clearly that the figure he has assumed is, as he states, almost a theo- retical one, not to be expected in practice. In fact, with the ore last mentioned, we find that 4808 thermal! units per pound of pig iron would be all that could be ob- tained theoretically in a blast furnace, and 4536 thermai units per pound all that an electric furnace, working perfectly, could give. Results Obtained in Practice, If we now turn to the results of actual practice, con- tinued day and night for weeks, such as we have ob- tained with a current of 200 horse-power, smelting, elec- trically, pig iron at the rate of over 1 ton a day, asa special by-product, so to speak, of other manufacture, the current not being estimated, but carefully measured with proper instruments and recorded daily for the electric power company who furnished it and were charging for it, we find that under favorable conditions we obtained from the ores, of which the composition is given above, a yield of 87 per cent. in metal and an average yield of 80 per cent. under ordinary circum- stances of running. We should remark, however, that our furnaces were not well adapted for the purpose of running continuously because they had been originally built for intermittent running. The metal was tapped at regular intervals, as with a blast furnace, though much more frequently, the size of the furnace, which we had to take as it was, not allowing the accumula- tion of more than a fraction of a ton in the hearth proper. Under these conditions, reckoning on the 200 horse- power supplied, we required per kilogram of metal ob- tained from weighed charges 2900 calories in the best runs (87 per cent.), or 5220 thermal units per pound, a figure likely to be obtained regularly with a better con- structed apparatus, and, under our less favorable con- ditions, as general average, 3150 calories per kilogram, equivalent to 5670 thermal! units per pound. Now since 1 horse-power equals 640 calories equals 2560 thermal units, the above figures correspond with 87 per cent. yield to 2 horse-power per pound hour, or 1% pound per 1 horse-power, or 186 horse-power per gross ton of pig iron in 24 hours, and with 80 per cent. yield (general average of ten weeks of running), 220 horse-power per pound hour, or 0.454 pound per horse- power hour, or 200 horse-power per gross ton in 24 hours. In short, we are justified, based on these absolutely practical results, which include losses of all kinds, by radiation, by imperfect insulation, by incomplete reduc- tion of the charges and passage of oxide of iron in the slag (results which, in fact, represent the net yield of a given amount of ore under the action of a meas- ured energy), to consider 200 horse-power per gross ton day as a practical figure easily obtained under indiffer- ent conditions of apparatus and working, and one which might likely be expected to be bettered and brought to possibly 180 horse-power under more favorable circum- stances. It is the higher figure, 200 horse-power per gross ton a day, that we will adopt as a basis in the comparisons of the two processes of smelting which we will make later. All that we have said above, relating of amount of calories required per kilogram of pig iron smelted, may be résuméd in a tabulated form as follows: Table I. $ wow Ho 85u ye she ff Pid Ses 82 888 § 2 =: a osc 2 ca a on 2am SOG Me Ga—- DTlio 6a o wt P eee & ae Su 8 ei $ Ses 5283 s2e ote & - «ee ° Calculations made on the Estimated Stassano process (a)..3,645 0.750 1.83 125 and consid- ered as con- firmed by a test of one hour on a few kilo- Calculated by the author grams. on ee es 000 0.636 1.57 146 Nance gineering News ).. 4, . . Yield of 85 Same as (b) with an esti- oa per mate of 85 per cent. aw = Wir CG aie sce cnd aes 4,700 0.541 1.84 171 one practi- cal run- ping. Voldenberg furnace, = Blast furnace calculation oa ~~ of balance of heat by . one i Lebedur (d).......... 4,750 0.550 1.85 172 in balance nam k Blast furnace same as a ae (d), calculated by Le- ee debur; 87 per cent. DF heat only heat acounted for (e).6,996 .... -+» 255 accounted for on bal- =e _— Same as (e), assuming Seaatietantn that all heat in blast oe furnace would have heat ac- been accounted for (f) .6.086 222 counted for. Calculated by us for the ‘Sen tee special ore mentioned, nace ac- on the same basis as in counted for blast furnace (g)...... 4,808 0.551 1.88 173 theoretical- Practically obtained by All charges us as a result of day also. metal and night runs for obtained: weeks; good runs 87 current per cent. yield with measured same ores as (g) (h)..5,220 0.500 2.00 186 with prop- Same as (h); average of Sesunt tee good, bad and indiffer- tric ' fur- ent runs for the whole nace. run of ten weeks in electric furnace....... 5,670 0.467 2.14 200 Do. In our furnaces, operating as they did and con- structed as they were for a specific purpose, the gas escaping at the top was carbon monoxide, which began to burn to carbon dioxide only when close to the top. It was formed in place by the burning of the particles of carbon at the expense of the oxygen of the oxide of iron of the particles of ores, which were intimately mixed with those of carbon. The furnace being open, the heat thus generated by the combustion of CO to CO, was practically lost. That it might have been utilized to prepare the charges for reduction as they were fed into the furnace is evident. To a certain extent this 2s J 4 ? e £ ~” : i ; . y , 5 e i ‘ ee ; f : , a tu ed. -, ey i : « = - ¢ i Be in , t bs f Z + et it A * ; - ob we pus o it , i Bu ee si b * h ri ips 8S ooo pean egrets? Kea EE IS <i 8 THE IRON AGE. was secured in a crude manner, but not to the full heating value of the gases and in a much less effective manner than ina blast furnace. In the latter apparatus there is also a serious loss on this score of the heat carried away by the escaping gases and still available after the preheating of the blast, but we doubt if the heat from the escaping gases in our furnaces, as con- structed for specific purposes and not specially for iron ore smelting, was utilized any further than to compen- sate for the losses by radiation. On this score, then, there would be a legitimate hope of obtaining somewhat better results as to horse-power consumption per gross ton in 24 hours than that assumed—viz.: 200 horse- power per gross ton. Cost of Power. The figure of $20 per electrical horse-power per year, which the writer of the article mentioned considers a minimum, may be called, on the contrary, almost a maximum. The current can be had at $18 per year in many places and has been offered to us at $15 for moderate amounts and at as low as $12.50 for several thousand horse-power. In certain districts as low a price as $10 per year could be obtained, and where it would be produced in place by the parties utilizing it at cost price or nearly so, certainly a figure of $8 per horse-power a year or even less does not appear to be too low. We have seen that in Italy it could be se- cured at a cost of $13.50 per year for 3000 horse-power. It is one of the elements of the comparison of the relative economy of the two processes which the writer of the article does not seem to have taken into consider- ation in his conclusions. It is also obvious that an elec- tric plant would not be established in competition with a blast furnace in a district where ores, fuel, fluxes would have to be transported from a long distance at a great cost, but, on the contrary, at the very places where ores could be had on the spot at the cost of mining, so to speak, and where the electric power could be bought or created at a reasonable price. In many districts a local industry would be justified under ad- vantageous conditions of prices of ore and current, es- pecially in such districts where the cost of transporta- tion of pig iron made in blast furnace for general use becomes an item of great importance, in fact is almost prohibitive, and where coal may be of such quality as not to be fit for blast furnace purposes. We were told by parties on the Pacific Coast that the freight charges on pig iron by railroads amounted to $10 a ton in some places. Even were it to be much less, were ores to be had in these regions (as they are) at a low price, and the parties we refer to told us they could be had at 50 cents per ton at the electric furnace, and that coal unfit for blast furnace was found in close proxim- ity, would not these favorable circumstances justify electric smelting, though they would exclude a blast furnace treatment? Water power, we were told, could also easily be made available for electric purposes at the cost of creating it. To be economical a blast fur- nace must be of certain dimensions; an electric fur- nace, within wide limits, can be made of any dimen- sions desired or the furnaces multiplied. The economy lies in the power available and not in the size of the smelting apparatus. In the northern districts of New York and in many other States of the Union, there are large deposits of ores which, on account of present lack of means of com- munication, if for no other reason, are excluded from the general market; such, for instance, are the ores that we have smelted both in the blast furnace and electric- ally. They did yield, in both cases, an iron of superior quality, particularly well adapted for specific purposes and for which we have obtained a special price. They are rich in iron (57 to 60 per cent. iron) and practically free from phosphorus and sulphur. They can be mined in open quarry for many years to come and could be delivered, we were told by the owners, at 50 to 75 cents per ton at the electric furnace (all included); char- coal, as reducing agent, is at hand:and limestone is within carting distance. Water power to the extent of possibly 20,000 horse-power could be cheaply and easily developed in these mountain ore districts. Would not, under these conditions, an electric furnace solve the November 20, 1902 present difficulties, specially if, by the smelting of these particular ores, having peculiar characteristics, a pig metal commanding a better price on the market can be and infact has been obtained from them? It is easier to build up a railroad spur for a manufactured product than one to transport all the raw materials necessary for a manufacture. We do not claim that an electric furnace or plant could be established and worked profitably anywhere or near our monster modern blast furnaces producing 500 and 700 tons per day or more; nor, at least in the present state of the arts, that they can be made of the same proportions as these metallurgical colossuses; nor that an electric installation could compete with a blast furnace with materials, ores, fuel, stone, delivered at the same price at both plants unless the electric power could be delivered at a figure lower than we can now expect; nor that, under conditions of approximate equal- ity of cost, the electric installation should in all cases be necessarily preferred, but a power of some 5000 horse-power can be developed at a comparatively moder- ate price in mountainous districts and others favorably located. Electric smelting does not require the com- plicated and expensive machinery and apparatus of a blast furnace, nor does it require, excepting the elec- trician in charge of the plant, particularly skilled labor. In other words, we do not hold that all the blast fur- naces are to be replaced by electric plants, but we claim that favorable local conditions of labor, of the supply of ore and other materials, of the electric power and of reaching markets may justify profitable work by elec- tric smelting. Another of its advantages is that, in case of trade depression and unprofitable prices, it is enough to throw off a switch to stop the works and that manufacture can be resumed at once by turning it on again without any special outlays. The addition of a few extra furnaces at a small cost allows even an increase of output if justified by the demand; fur- naces which can be built at a short notice. We believe, then, that under certain contingencies the cost of elec- trically smelted pig iron may be as low as or materially lower than that of pig iron obtained in a blast furnace. Comparison of Cost of the Two Processes. Let us then assume that where such an electric plant should be established, for a production of say 30 to 50 tons of pig iron a day, we have an ore of 57 per cent. of metallic iron, general average of mine; of limestone at $1 a ton, coke at $2.50, the ore being de livered at the electric furnace at 75 cents a ton, a price which has been made to-us and even a lower one in certain districts. Let the price of current be $10 a year per horse-power (for 365 days of 24 hours). This cannot be considered too low a figure for generating the current at cost price for its own use, thus not re- quiring the costly establishment rendered necessary for the storing and regular distribution of the current to sundry customers. In fact, in certain districts the cur- rent is offered at that price by power companies. The amount of limestone required in the case of electric smelting can certainly be taken to be the same as for the same ores smelted in a blast furnace; if any- thing it should be less, because we need not take in consideration the ashes of the fuel to the same extent to which is has to be done in the blast furnace. The- fuel (carbon in some shape) used for the electrical re- duction of the iron oxides, amounting to say one-quarter to one-third of what is required in the blast furnace. The labor, incidentals, superintendence, &c., in a blast furnace certainly vary with the daily production. These items are generally estimated at about $2 per ton and less as the output increases. It need not be any higher in the electric furnace, at any rate, and for the com- parison of the two methods the figure adopted is of sec- ondary importance. Half a ton of limestone of average composition per ton of pig iron should be considered ample in both cases with such rich ores as we will assume to be smelted— that is, Bessemer ores at