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By S. A., Taylor

IT is very difficult to arrive at exact figures for the cost of maintaining excess capacity of coal mines, but we can approximate the various items. To do this, I will take the Pittsburgh district of Pennsylvania and the other districts can be compared to this one. I believe we can take the depreciation item of plant ac- count as a whole and discount it over a period of 20 years; while this is high for some items it is low for others and I believe it is not far from a safe basis. This equals 5 per cent per year, and this depreciation will take place about as rapidly when not in use as when in operation. A fair value in the Pittsburgh district to- day for plant and houses is close to $4 per ton per annum. At 5 per cent this will equal 20 cents per ton per year. The item of keeping the mine in condition, free from water, etc., will be close to an average of 2y2 cents per ton per annum.

Jan 1, 1928

By A. W. Hale

IN a work published in 1838, De Morgan, the author of the article on "Probabilities,' in the Encyclopedia Metropolitana, says " The method of least squares is not yet introduced into the affairs of common life,….that many things which are demonstrable only by the higher branches of mathematics are looked upon as useless." And he mentions an instance in which "a method was suggested for estimating the relative importance of boroughs, by considering their population and contributions to the revenue com-

Jan 1, 1881

By I. H. Warren, E. Devuyst

A review of the physical and chemical aspects of the direct leaching of metal oxides has been given and com- pared to recent data of the authors and co-workers. The physical aspects, including the anisotropy of the dissolution, the hydration and the zero point of charge of some metal oxides are discussed first and then the kinetics of the dissolution of metal oxides are considered. A general mechanism of the leaching of oxides which describes most of the observed results is proposed.

Jan 1, 1973

By AIME AIME

N EARLY 1300 members and guests crowded the halls of the Engineering Societies Building during the winter meeting of the Institute just closed, and more than 600 attended the banquet. In variety of program, quality of papers, interest in discussion, and brilliance of social features, the meeting maintained the high reputation of the past. Nothing elaborate in the way of excursions was attempted, experience having proved that February weather in New York is much too uncertain to warrant extensive field trips. A sight-seeing journey up the Hudson to the Bear Mountain bridge was, however, made despite the snows of the week before and the week after. The annual business meeting, while attended by a minority of the members in the building, was marked by the display of keen interest in the work and called out several interesting discussions. The excellent reports of the committees that had organized their work and directed it along definite lines, emphasized the need of funds with which to support assistants or Fellows who shall correlate and put to the highest use the facilities of the Institute in research along technical lines. This thought was developed at the banquet by the retiring president, J. V. W. Reynders, and it is expected that the Directors will take early steps to collect a fund for this purpose. The number of the individual sessions was too great and the papers and discussions too numerous to permit mention here of all the features of inter- est. A general review only follows. The papers and detailed discussions will be printed and sent to members as promptly as possible.

Jan 1, 1926

THIS chapter and the one following deal with the heat quantities involved in open-hearth steelmaking, including the thermal efficiency of the furnace as a generator of high-temperature heat, the heat storage in the steel and slag produced and in the furnace walls, and the heats of the various chemical reactions involved in combustion, in the formation of slag, and the refining of steel. The fundamental laws to be considered are the simplification of the first two ' laws of thermodynamics as applied to problems involving sensible and potential (or latent) heat only 1. Heat input equals heat outflow plus storage. 2. Heat may be transferred only from a hotter body to a colder one. The first of these laws relates to the various heat quantities or the "heat balance" of the process. No one has as yet made an open-hearth heat balance that came out almost exactly balanced, and we assume that the cause lies in the difficulties of accurate temperature and flow-rate measurements at the high temperatures involved and the inherent complexities of flow distribution, air leakage, etc., present in any real, open-hearth furnace system. Some idea of the magnitude of the heat quantities involved can be obtained- by a brief, crude outline of the heat balance of a 90-ton heat of steel. We will assume a 60 to 70 per cent hot-metal charge in a fairly fast working and only moderately efficient furnace, burning fuel oil, with a fuel consumption of around 4 million B.t.u. per net ton. of ingots produced. The time from start of charge to tap is 9 hr. During this period, the oil burned represents 360 million B.t.u., and the sensible heat in the preheated air at the port ends is 117 million B.t.u. so that the total heat input at the ports is 477 million B.t.u. Heat stored in the steel and slag at the end of the heat, plus the various amounts absorbed by certain bath reactions, amounts to a total of 195 million B.t.u., but 120 million of this is supplied by the heat in the hot metal and by various heat--evolving reactions in the bath, so that only 75 million B.t.u. need be supplied to the bath by the flame.

Jan 1, 1944

By AIME AIME

A LUSTY baby of the Institute, the Coal Division, showed that it had acquired a full set of teeth and was capable of man's work at the Division meeting at Fairmont, W. Va., on March 26 and 27. At this second of a series of field meetings, the first of which was held in Pittsburgh last fall, the industry in the East was represented from top to bottom and good humor and enthusiasm were the predominant notes. West Virginians are always good hosts and this meeting would have proved the statement to any inclined to doubt it. The spacious auditorium of the Fairmont Hotel was arranged for the technical sessions, the hotel being headquarters for the meeting. About a hundred and twenty-five representatives were registered and in attendance when Thomas G. Fear, chairman, opened the morning session at 10 o'clock Mr. Fear first introduced Howard Eavenson, vice-chairman of the morning program, who, as chairman of the Coal Division, had labored long and cheerfully to make the meeting successful. Mr. Eavenson talked briefly on what the organization was doing, pointing out that these field meetings were designed to bring the members into closer touch with the parent Institute and give the younger engineers in the field a better opportunity to participate in the work the Institute is doing. He congratulated the various committees for their work in promoting the meeting.

Jan 1, 1931

By W. W. Vaughn, R. H. Barnett, E. E. Wilson

Soon after the search for uranium ores on the Colorado Plateau began in earnest, thousands of feet of drill core ranging from 1 1/8 to 2 1/8 in. diam became available for study. Although significant advances had been made in the technique of quantitative gamma-ray borehole logging, instrumentation was in the development stage, and complete reliance could not be placed on gamma-ray logs alone to interpret quantitatively the meaning of radioactivity in a drillhole. A method that would be faster than chemical analysis and still give reproducible and reliable results for various drill core sizes was desirable to provide additional information on the enormous footage of drill core being accumulated. A solid phosphor scintillation drill core scanner was designed and constructed. Basically the instrument was developed to measure radiation from a drill core which would not be clearly recorded by a gamma-ray logger using a Geiger tube as the sensitive element. Such data would be beneficial in constructing isorad maps to delineate ore-bearing zones. A calibration in the range 0.01 to 0.1 pct eU.,O, was provided; above 0.1 pct eU3O8 gamma-ray logs were available and were being used to calculate grade and tonnage of ore reserves. The core scanner, however, has been used to estimate equivalent uranium content of ore-grade materials containing as much as 2.2 pct eU3O8 with an accuracy of ± 10 pct, the sample being in the form of a BX drill core. Actually, an apparent calibration of eU3O8 vs counts per unit time is a straight line with a slope that is a function of the sensitive element and the geometry of the counting assembly. A true calibration that will show the expected departure from a straight line is due principally to the random nature of the pulse from a radiation source and the nonlinearity of the electron circuitry. Design and Construction: Three methods of detecting radioactivity were considered and applied in developing the core scanner now in use: 1) the Geiger tube, 2) liquid scintillation phosphors, and 3) solid scintillation phosphors. The desired sensitivity and long-term drift characteristics needed for this operation could be attained only by using solid scintillation phosphors. All three methods are discussed. Before scintillation counters were common, nine beta-gamma sensitive Geiger tubes 7/8 in. diam by 12 in. long were used, arranged to surround the drill core with tube axes parallel to the axis of the core. This arrangement of Geiger tubes was en- closed in a lead shield 1 in. thick, and provision was made to slide a 6-ft length of drill core manually into the counting chamber, one foot at a time. A count for each segment was taken with a scaler while the core remained stationary. The equivalent uranium content of the different sections of drill core could then be estimated with the aid of a calibration curve of counts per unit time vs percent equivalent uranium (eU). In rare cases the effects of the radioactivity concentrated in small areas within the core introduced errors in the readings made with the Geiger tube arrangement owing to the geometry of the measurement. The variability of counting rate due to a localized concentration of radioactivity in a spot in the wall of a drill core is illustrated in Fig. 1. This effect and the inherent low efficiency of the Geiger tube were considered major disadvantages of this counting arrangement. When liquid scintillation phosphors became available the core scanner in Fig. 2 was constructed to make a more accurate measurement of the equivalent uranium content of a sample. This instrument contains about 4 liters of liquid phosphor in a stainless steel coaxial cylinder 1 ft long, with inner and outer walls 0.060 in. and 0.125 in. thick, respectively. Four end-window type photomulti-plier tube with cathodes of 2 in. diam, immersed in the solution at right angles to the axis of the core, were used to observe light flashes in the phosphor. The liquid phosphor offered equal sensitivity to radiation originating at any point in the enclosure and represented geometrically the optimum in design. However, providing a semi-permanent leak-proof seal between the glass envelope of the phototube and the metal walls of the container proved to be a serious problem in constructing the equipment. The most effective seals were especially machined O-rings from sections of large tygon tubing. The tygon took a permanent set owing to cold flow characteristics and in most cases sealed completely. The light absorption characteristics of the liquid phosphor changed gradually with time, and after one month the counting rate had decreased to half the original value. The most sensitive liquid phosphor tested proved to be a solution containing 4 g of 2.5-diphenyloxazole and 0.01 g of 2-(1-naphthy1)-5-phenyloxazole per liter of toluene. With fresh solution in the chamber and with all photomultiplier tubes operating in parallel, the counting rate contributed by any one of the four photomultiplier tubes was about 85 pct of the counting rate from a single tube operated individually. From these observations it was concluded that owing to coincident loss and light attenuation within the liquid phosphor, the apparent sensitivity could not have been materially increased by additional phototubes. However, this approach to core

Jan 1, 1960

By D. P. Kedzie, R. A. Dodd

The fatigue strength, fatigue hardening, and effect of fatigue deformation on subsequent age hardening of supersaturated Al(Cu) solid solutions have been determined as functions of alloy composition and temperature. The fatigue strength/tensile strength ratios, determined at 150°, 25°, and -195°C, decreased with increase in alloy content for all temperatures, but the F.S./U.T.S. ratios at -195°C decreased much more rapidly than did the ratios for 150" and 25°C. This suggested that strain aging and/or age hardening occurred during tests at higher temperatures. Additionally, the F.S./U.T.S. ratios at 150°C exceeded those at 25°C for all compositions, indicating greater strengthening during fatigue at 150°C. The effect of fatigue or tensile deformation at 150°, 25°, and -195°C on subsequent age hardening showed that the deformatzon increased the rate of precipitation and indicated that mechanically produced vacancies were probably formed during deformation. Fatigue hardening was studied at 150°, 25°, and -195°C, and the effect of room-temperature rests after 10 and 100 cycles was examined. The results confirmed that strain aging occurred at the higher temperatures . DURING the last 15 years various mechanisms of fatigue crack nucleation and growth based on dislocation and vacancy interactions, operating singly or collectively, have been proposed. The probable consensus of present opinion is that the fatigue process in pure metals essentially involves dislocation interactions, and that vacancies formed by such interactions play a minor or inconsequential role. However, there is some evidence that age-hardened alloys tend to overage during fatigue, probably by local vacancy-enhanced diffusion, and strain aging also might be important in selected cases. Furthermore, it has been established that the behavior of quenched-in vacancies in Al(Cu) and other solid solutions is composition-sensitive. Therefore, it seemed worthwhile to investigate various aspects of the fatigue behavior of supersaturated Al(Cu) alloys and to examine the results in terms of vacancy-enhanced effects. EXPERIMENTAL The alloys used in this investigation were prepared from 99.994 wt pet A1 and OFHC copper, the latter containing 0.04 pet 0 as the principal impurity. Six alloys were made, containing, by actual analysis, 0.58, 0.96, 1.96, 2.85, 4.45, and 5.51 wt pet Cu. They were induction-melted in air in graphite crucibles, cast as 7-in. by 7/8-in.-diam rods in graphite molds, and hot-rolled to 5/8 in. diam. The experimental work was a three-part program involving the determination of a) 10' cycle fatigue stresses as a function of alloy composition and temperature; b) the effect of fatigue deformation on subsequent aging of the supersaturated alloys; and c) fatigue hardening as a function of alloy composition and temperature. For determining the 105 cycle fatigue stresses, a portion of the 5/8-in. stock was machined into Krouse rotating cantilever beam fatigue specimens, 2 in. in length by 1/4 in. minimum diameter. These were tested at +150°, 25°, and -195°C (liquid nitrogen) on a Krouse high-speed machine, with special weights to provide lower -than-normal loading ranges, this being necessitated by the small load requirements of those alloys of lower copper content. For the high-temperature tests a small resistance heater was designed to clear the collets and fit in between the chucks, while for the low-temperature tests a hollow nylon cylinder was used, having closed ends drilled to pass a fatigue specimen, and positioned similarly to the heater. A plexiglass container completely enclosed the fatigue machine; rubber gloves fixed to ports in the walls enabled the machine to be operated from outside the box. A tray of magnesium perchlorate dried the air in the container and prevented both atmospheric corrosion fatigue at room and elevated temperatures and troublesome ice build-up at low temperatures. A total of ten to fifteen specimens was used for each combination of alloy composition and temperature. The result of each test was plotted on a standard S-N diagram, and the next stress was selected on the basis of the trends indicated by previous specimens. In this manner a small portion of the S-N diagram was constructed, and the 105 cycle fatigue stress obtained. Small Krouse fatigue specimens were also used to study the effect of cyclic prestrain on subsequent

Jan 1, 1964

By E. F. Ketterer, D. B. Collyer, A. B. Wilder

AISI constructional alloy steels are a series of steels in which a numbering system signifies the chemical composition limits. SAE (Society of Automotive Engineers) and AISI (American Iron and Steel Institute) use basically the same numbering system. The steels contain, in part, alloy additions of chromium, molybdenum, nickel, and vanadium. They are used widely in the automotive industry but have not been adopted for high temperature service. The purpose of this investigation was to study changes in microstructure observed in typical AISI constructional alloy steels in the welded and un-welded conditions after exposure for 34,000 hr at 900" and 1050" and, in several instances, 1200°F. The tensile and creep rupture properties after exposure for 10,000 hr were also evaluated. The investigation is a continuation of the work previously discussed. Little was known concerning the existence of graphite in medium or low carbon steels before 1943. It is important to note that continued exposure at elevated temperature is required in order to develop graphite in steels. Interest in the presence of graphite in steel, and also in changes in the properties of steels after long service at elevated temperatures, developed after 1943 when a failure of a welded joint of high temperature piping was associated with the graphitization of a relatively low carbon content steel with 0.50 pct Mo,8,0 Numerous investigations have beeen made in recent years studying the relationship of this type of failure to changes in properties. Attempts have been made to evaluate the performance of a number of steels, particularly in the heat-affected zone of welds. It was the unfortunate failure of a weld-heated zone in high temperature piping in the steam-power industry which focused attention upon possible failures, and upon the need for improved steels for high temperature piping service. Investigation by the National Tube Div., U. S. Steel Corp., Lorain Works, has included a wide variety of steels in an attempt to learn the effects of numerous factors and elements upon the long time performance of steels, although many of the compositions studied will never be used at elevated temperatures.1,4-7 Included were the well established AISI steel series, which offered opportunity to test moderately high carbon content steels as well as observe the effect of nickel, chromium, molybdenum, etc., upon the properties of these well known steels. The properties of the AISI steels were also studied for comparison with the previously reported properties of the Cr-Mo steels, now used by the steam-power industry.5,7 Materials and Testing Procedure The AISI alloy steels in Table I were exposed for 10,000 and 34,000 hr at 900°, 1050°, and 1200°F.

Jan 1, 1958

By P. Chiotti, J. T. Mason

Metallographic, thermal, X-ray, and vapor-pressure data were employed in establishing the Ce-Zn phase diagram. Nine compounds and three eutectics were observed. The eutectic compositions in weight percent zinc and temperatures are 10 pct and 495"C, 37 pct and 795°C, and 56 pct and 810°C. Three of the compounds, CeZn, CeZnn, and CeZne.5, melt congru-ently at 825°, 87.505°, and 980°C, respectively; the other six compounds, CeZns, CeZns.67, CeZn4.5, CeZn5.25, CeZn,, and CeZnll, decompose peritectically at 820°, 840°, 870°, 885", 960°, and 795"C, respectively. The compound CeZn5.25 is an AB5 type with a small range of composition which lies on the zinc-rich side of the 1 to 5 stoichiometry. Zinc vapor-pressure data obtained by the dewpoint method were employed in calczilating the thermodynamic properties of both the liquid alloys and solid compounds. The data for the A critical review of the information available on the Ce-Zn system up to 1960 has been given by K. Gschneidner, Jr.' Of particular interest is the work by J. schramm2 who investigated the region between 55 and 100 wt pct Zn and reported a CeZn,, compound which decomposes peritectically at 785"C, a CeZn, compound which melts congruently at 972"C, and five temperature horizontals at 79@, 817", 840", liquid alloys were fitted to the relation from which the relation was obtained by integration. In these relations F XS is the excess partial molal free energy, N is atom fraction, and the constants c and d have the values c = (-22,000 + 7.0T) and d = 6171,000 + 74.0T). Relations for the standard free energy of formation for the solid compounds were derived from the data. At 973°K the enthalpy in kilocalories per gram-atom z)aries from —11.3 for CeZnz to —8.21 for CeZn~l and the free energy in the same units varies from —7.1 joy CeZn, to -3.82 for CeZn11. and 942°C in the region between 55 and 75 wt pct Zn. No attempt was made to identify other features of the system. I. Johnson and R. yonko3 used a fused-salt cell to measure the electromotive force between pure cerium and an alloy consisting of zinc-rich liquid in equilibrium with CeZnll. Solubility data for cerium in zinc has been reported by J. Knighton et u1 .4 Johnson and Yonko give the following equa-. tions for the mole fraction of cerium in zinc and the standard free energy of formation of CeZnll:

Jan 1, 1965

US 4,134,618-Method for restoring an underground reservoir subsequent to the solution mining of an ore body of uranium, copper, nickel, vanadium, molybdenum, silver, rhenium, or selenium. Clean water a cycled through the mined area, via the injection and production wells used during mining, at a flow rate sufficient to entrain residual dissolved solids. The solids are separated at the surface and disposed of, e g., in a deep disposal well, while clarified water is recycled C A. Kossack, assigned to Atlantic Richfield Co. Jan 16, 1979 4 pp. (299-5) Filed. 12-29-77 (865,646) US 4,155,982-In situ leaching of a subterranean uranium ore deposit The ore is leached with a dilute aqueous solution of ammonium bicarbonate containing a small amount of hydrogen peroxide in order first to convert tetravalent uranium in the ore to the hexavalent state and second to dissolve the hexavalent uranium preferentially to the other metals or elements commonly occurring In such ore The uranium- enriched leach liquor IS brought to the surface, and the uranium recovered by means of adsorption on a particulate ion exchange resin, elution with an acid, and treatment with ammonia to precipitate relatively pure ammonium diuranate. G G. Hunkin, T P. Fife, and J R Stano, assigned to Wyoming Mineral Corp. May 22, 1979. 13 pp (423-7). Filed: 10- 9-74 (51 3,445). Same: Canadian 1,027,849, dated Mar. 14, 1978. US 4,157,847-In the mining of sulfur by the Frasch process hot water accumulating above subterranean sulfur from previous mining operations is recycled downward to contact and heat additional solid subterranean sulfur. Advantageously, pressurized and superheated drive water from above ground is commingled with the underground water to raise its temperature before it is recycled downward R. L Williams, R L Latiolais, J. L Gabriel, and R. L Bouis, assigned to Freeport Minerals Co June 12, 1979. 13 pp (299- 6) Filed 7-28-77 (81 9,879). US 4,158,76%1n this method for determining the uranium content of a solution obtained in the solution mining of an underground uranium ore deposit, the intensity of gamma radiation from the Th-234 daughter of U-238 emitted by the solution is determined as it impinges on a scintillator after being passed successively through filter foils of a ytterbium- tin alloy, a lutecium-tin alloy, and a hafnium-zirconium alloy This scintillation is evaluated as a measure of the uranium content To assure that the uranium-thorium conversion has reached a stable state, the measurement should be made about three months after the uranium solution has been produced R C Smith, assigned to Westinghouse Electric Corp. June 19, 1979 11 pp. (250-255). Filed. 10-20-77 (843,770).

Jan 1, 1980

The Bougainville ore body was discovered in 1964 by a partnership of Conzinc Rio Tinto of Australia and New Broken Hill Consolidated Limited. The ore body is a porphyry copper in a fine-grained quartz diorite, which intrudes andesite volcanics and is located at an elevation of about 2, 000 ft in the Crown Prince Range of Bougainville in the Solomon Islands. Mineralization is predominantly chalcopyrite with some bornite and some gold and silver present. Rainfall in the area amounts to 200 in. (5. 08 m) per year. An active volcano is situated only 24 miles (38.4 km) from the mine, and all structures were designed to resist seismic shocks. An interesting and unique feature of the Bougainville operation was that the overburden was stripped with hydraulic monitors. Bougainville Copper, at 90,000 tpd, is the largest copper concentrator to be designed and constructed at one time; and besides the twin 54 in. by 74 in. Allis-Chalmers gyratories, it features seven 7 ft (2. 13 m) standard and fourteen 7 ft shorthead crushers, in addition to nine 18 ft diameter by 21 ft long (5. 5 m by 6. 4 m), 4250 hp, single -stage ball mills. During the design stage of the Bougainville primary crushing plant, several alternates were studied because the ore was expected to break with the production of large amounts of small-sized particles but with a minimum of fines. These alternates included two 54 in. by 74 in. gyratories with grizzlies, two 60 in. by 89 in. gyratories, and one 72 in. by 96 in. gyratory, the latter two installations without grizzlies. The two 54 in. units with grizzlies were finally selected as giving good reliability and the ability to handle the large amounts of small material in the feed. As originally installed, grizzly bars were set at 8 in. (203 mm); but, in an effort to perform more interparticle crushing in the primary and less rock-on-steel crushing in the secondaries and tertiaries, a test is underway (1976) to determine the effect of using 6 in. (152 mm) grizzly spacings (see write -up on Anaconda's crusher at Butte). The Bougainville ore is mined with 17 cu yd (13 cu m) shovels and hauled in 105, 170, and 210 st trucks to the crushers, which are equipped for two-side dumping. Up to 40% of the ore passes the grizzlies, which are equipped with splitters; and additional horizontal splitter bars are located directly above the spider caps. Because of the grizzlies, the crushers are supported by unique U-shaped enclosures, which are in turn supported by the end and center walls of the installation.

Jan 1, 1978

By W. J. Romanow

RECENT papers by Williams, Sherwood, and Boothby,1 Seybolt et al.2 Heikes; and Roberts4 attest to the increasing importance of the hexagonal ferromagnetic compound MnBi. Since the magnetic properties of MnBi crystals are highly anisotropic, it is useful and necessary to have appropriate aids for determining their orientations—a (00.1) standard stereographic projection and a corresponding table of crystallographic angles for this structure. The tables of crystallographic angles for the hexagonal system available in the literature5 are computed for c/a ratios greater than that of MnBi and cannot satisfactorily be used to find the crystallographic angles of MnBi. A table of angles between the crystallographic planes (HK.L) and (hk.1) was calculated for MnBi from the formula0 F=are cos Hh+Kk+ 1/2(Hk+hK) + 3/4 (a/c)2Ll/v(H2 + K2 + HK + 3/4 (a/c)2L2) (h2+ k2+hk + 3/4 (a/c)2l2) on an IBM Type 650 Magnetic Drum Data Processing machine. The lattice constants used are listed in Table I and are those determined by Willis and Rooksby7 at 20°C. More recently published values obtained by both X-ray and neutron diffraction"' show no difference from these significant to the calculation. From the crystallographic angles between the basal plane (00.1) and the general plane (hk.1) in Table I, an (00.1) standard stereographic projection was made for MnBi which is shown in Fig. 1. Acknowledgments The author wishes to thank R. G. Treuting and J. N. Hobstetter for their technical assistance, and Miss D. P. Booth for programing the IBM machine for the calculations. He appreciates the opportunity to read the paper of B. W. Roberts of General Electric Co. prior to its publication. References 1H. J. Williams, R. C. Sherwood, and 0. L. Boothby: Bulletin Amer. Physical Soc., 1956 vol. 1, p. 132. 2 A. U. Seybolt, H. Hangen, B. W. Roberts, and P. Yurcisin: AIME Trans., 1956, vol. 206, p. 605: Journal oF Metals, May 1956. 3R. R. Heikes: Physical Review, 1955, vol. 99, p. 446. .B. W. Roberts: A Neutron Diffraction Study of the Structures of Manganese B.W.Roberts:ANeutronDiffractionBismuthide, Physical. Review, 1956, vol. 104, p. 607. 5 A. Taylor and S. Leber: AIME Trans., 1954, vol. 200, p. 190; JouRNal of Metals February 1954. « C. S. Barrett: Structure of Metals, 2nd Ed., p. 635. McGraw-Hill Book Co. New York and London, 1952. 7B. T. M. Willis and H. P. Rooksby: Proceedings Physical Soc., London, 1954, vol. 67B, p. 290.

Jan 1, 1958

By Arnold K. Reese

It is not the purpose of the writer to set forth in these notes anything new or surprising in blast-furnace practice, but simply to lay before the Institute the somewhat unusual results obtained during a period of six consecutive months, ending April 30, 1896, at the Dover furnace of the Penn Iron and Coal Co., and to give, with these results, the conditions under which they were obtained, and all figures pertaining to that period. This plant was entirely rebuilt, on thoroughly modern and improved plans, in the spring of 1895, by Frank C. Roberts & Co., of Philadelphia.

Jan 1, 1898

By Wilhelm Borchers

IN all special branches of the chemical and metallurgical industries, in which large electric furnaces became necessary for carrying out new processes or for the improvement of old ones, the development of the electric furnaces took place on much the same lines. The endeavors to make a success of a new idea brought forth many ingenious designs, which, however, almost without exception, furnished the proof that the safest and shortest way to practical success is the utmost simplicity of construction of the necessary apparatus. Our knowledge of the qualities of materials for building electric furnaces and of the constituents of the furnace-charges, especially their electric conductivity and their chemical affinity . towards one another at high temperatures, is still far from being complete, and from this fact we must conclude that the smaller the number of elements in the construction of a furnace, the fewer the number of unreliable factors both in the construction and in the operation of the electric furnace. This conclusion deserves special attention when an electric furnace for making steel has to be chosen from the constantly growing number of inventions, inasmuch as the chief con¬stituent of steel, the element iron, is a substance which in its liquid phase has so great an affinity fir those elements which are to be removed from the charge, that it is very difficult to comply with the following conditions: 1, to beat the refining-slag to the highest point of its chemical activity ; to prevent the iron from entering the slaw, or, where this cannot be done, to make it enter so that it finally appears in the end-product

Jan 1, 1910

By CHARLES M. A. STINE

IN fighting a war the all-absorbing intent is to win. There is little time to analyze the rush of events or to appraise their consequences beyond the war's end. The united objective is, rightly, success for our arms. Yet under the pressures of a great war there may be compressed scientific, economic and social developments that might have taken many decades to achieve under less urgent conditions. Their effects on our lives and all civilization may be more wide-reaching and lasting than any military conquest. They constitute one of the must imperative incentives to victory. No American, least of all any scientist worthy the name, conceivably could endorse war as a justifiable means to progress. The destruction of life and property wrought by the present war far exceeds the havocs of a century's earthquakes. Most of mankind is burning itself on an altar of paganism. Nonetheless, one fact is inescapable Despite the recurrent malady of war history's overall course is forward. Mankind has the habit of rising phoenix-like from its own ashes to attain greater heights. Progress is immortal.

Jan 1, 1942

HIGH-GRADE manganese ore, from which manganese is obtained commercially, is not found in large quantities in any major steel-producing nation in the free world. The U. S. is a "have not" nation with respect to deposits of directly mineable high-grade manganese ore. Known resources of 48 pct Mn or better grade ore amount to less than 200,000 tons. In 1950 the U. S. steel industry consumed 1.8 million short tons of metallurgical grade manganese ore that contained about 800,000 tons of manganese. About 16 pct of the manganese content was lost in processing, so that about 650,000 tons, or 13 pounds per ton of steel actually entered into steel production. Under present practices use expands directly with steel output, and by 1975 the demand in both the U. S. and the rest of the free world is expected to be roughly 60 pet greater than in 1950. In peacetime about 80 pet of manganese consumption goes into steel production; high-manganese steel, dry cells, and chemicals account for the remainder. The manganese supply problem centers around high-grade ore for ferromanganese production. Use of ores containing less than 35 pet Mn sharply increase the costs of making ferromanganese. Use of ferro-manganese of grade below 70 pet in turn requires changes in steelmaking that increase steel cost. Under normal conditions the present small domestic production cannot be expected to increase. Major resources in the U. S. consist of 12 low-grade deposits. The cost of mining and treating these ores to extract a product as good as that yielded by imported ores is at least twice and in some cases more than four times the 1951 price of foreign ores delivered to the U. S. However, as long as trade relations and overseas shipping are not interrupted, deposits in India, Africa, and Brazil can meet steadily increasing demand at approximately present costs. Cost considerations indicate that the U. S. should continue to rely upon overseas sources for its peace-time supply, and that this situation is satisfactory. But, this does not take into account the question of how the U. S. will be able to meet its needs in war. Position of the Rest of the Free World In 1950, free world steel producers outside the United States, with a steel output of 70 million ingot tons, consumed about 1.3 million tons of metallurgical-grade ore. Their manganese ore demand, expected to increase directly with steel production, will by 1975 be about 2.3 million tons. Russia possesses over half the known manganese ore reserves of the world and is producing twice the tonnage of any other country. It supplied more than a third of the U. S. manganese requirements up to 1938 and again in 1948, but by 1950 Soviet manganese exports to the free world had virtually ceased. The free world's supply of manganese now comes mainly from India and Africa. Somewhat over 10 pet of U. S. imports came from Brazil and Cuba. Security Considerations In the event of war the U. S. might be substantially cut off from 90 pet of present sources. Reduction in manganese specifications might cut consumption by over 10 pet without seriously affecting steel quality. By elimination of losses in the production of ferromanganese savings as high as 10 pet might be possible. But, wartime manganese requirements cannot be met through conservation alone. To meet possible future emergencies the U. S. should continue its comprehensive security program for manganese, including stockpiling and research on the economic use of low-grade ore, domestic ores, the recovery of manganese from slag and the reduction of manganese requirements in steel production. If this work, including additional pilot plant operation is pursued vigorously, it should be possible in an emergency to get an adequate supply of manganese from domestic sources. The national stockpile then can be looked upon as a source of supply during the period of at least 2 years required to reach full-scale production from low-grade resources. Ferromanganese Smelting In comparison with smelting of pig iron, ferro-manganese smelting is a very wasteful process. Under present ferromanganese blast-furnace smelting practice, about 8 pet of the manganese in the furnace charge is lost to the slag, and roughly the same amount is lost to the stack gases; the total loss approaches 15 pct. Present practice is a compromise between excessive slag loss and excessive stack loss. In fact, it may be seriously questioned whether conventional blast furnace design is suitable for manganese smelting. U. S. Resources The known manganese deposits of the U. S. contain a total of 3500 million long tons of raw material and 75 million long tons of metallic manganese. More than 98 pct of this contained metal is in 12 large low-grade deposits of which the most important are those at Chamberlain, S. Dak; Cuyuna, Minn.; Aroostook County, Maine; and Artillery Peak, Ariz. Reserves of high-grade ore (48 pct Mn) amount to less than 200,000 tons. About 20 million tons of ore average over 15 pct Mn, and when grade is decreased to 10 pct Mn reserves amount to about 100 million long tons. If cut-off grade is decreased to 5 pet Mn, resources amount to 800 million long tons. Many of these low-grade ores may be beneficiated by flotation or other concentration methods. Pyrometallurgical Methods For smelting ferromanganese, it is essential to have an ore containing at least 50 pct manganese, with an Mn:Fe ratio of about 8:1. Direct smelting of 20 pct Mn concentrates is not promising. The only method that offers any promise involves two-step smelting.

Jan 1, 1952

By B. A. Kulp, R. R. Reeber

Lattice parameters for the wurtzite form of' CdS mere measured by powder X-ray diffraction techniques over the temperature range 26° to 1000 K'. A negative thermal -expansion coefficient was determined parallel and perpendicular to the c axis below 13.5°K. Near 808°K, the curves of the a, parameter, the differential thermal expansion, and the resistivitv vs absolute temperature exhibited a reversible discontinuity. j\. direct determination of the lattice parameters of CdS over an extended temperature range is of particular use in interpretation of the effects of high pressure on the band structure of semiconductor materials. For example, Langer' has studied the effects of pressure on the absorption edge of CdS from 77°K to room temperature. In order to properly interpret his results it is necessary to know the change in lattice constants as a function of temperature for the wurtzite, zincblende, and rocksalt2 modifications of this material. Thermal-expansion measurements for CdS, wurtzite phase, have previously been determined over a limited temperature range.s74'5 The zincblende phases, of other compounds with similar bonding, have been investigated by Novikova et a! .'' Previous thermal-expansion measurements for metals with hexagonal symmetry have for the most part used bulk sample techniques for low-temperature result. Most X-ray measurements at low temperature have been on materials with cubic symmetry.'jQ The use of X-ray powder-diffraction techniques offers a convenient and accurate method of measurement over a wide temperature range. The X-ray method, besides measuring unit cell size, also provides information about change in structure type and the nature of some of the stacking defects present. I) EXPERIMENTAL PROCEDURE The thermal expansion was measured by X-ray powder-diffraction techniques. Lattice parameters for the range 300" to 1000°K were determined in a 19-cm Unicam camera. From 26" to 300°K a 34-cm back-reflection camera with the Van Arkel" film arrangement was used. The sample was bonded to a copper cold finger below a helium, hydrogen, nitrogen, oxygen, dry ice, or ice brine bath in a metal cryistat. che inner bath was surrounded by another one for radiation shielding. Nitrogen was used in this outer bath for the very low-temperature runs while dry ice and acetone was used for the 195°K point. CuKa X-rays, filtered with a nickel foil, entered the cryostat through a 0.001-in.-thick aluminum window. During a typical 9-hr exposure the sample was continuously rotated through a 30-deg arc. Heat losses from the sample holder limited the minimum temperature attained to 26°K with helium in the inner dewar. Temperature calibration between 25" and 125°K was determined with an Allen Bradley 300-ohm carbon resistor. The resistor was attached to the back of the copper finger with a thin layer of silicone grease. Liquid He, HZ, N2, and O2 baths were used to calibrate the resistor. Temperature variation is estimated to be *2"K with a slightly higher uncertainty at room temperature and 264°K. The thermal expansion of high-purity germanium from 373" to 900°K was measured as a calibration for the Unicam camera. This value was compared with the known value1' for the thermal expansion. A discontinuity in the thermal-expansion coefficient of the CdS a, parameter was observed. Similar discontinuities in the resistivity and differential thermal analysis at the same absolute temperature indicate that the temperature error is *5°K in the temperature range above 500°K. Temperature errors in the Unicam camera below 500°K are appreciably higher due to large gradients in the resistance furnace. II) SAMPLE PREPARATION The CdS was Eagle Picher ultrapure grade. The crystallite size range of the as-received powder

Jan 1, 1965

By W. G. SWART

THE best estimate on reserves of iron ore in the Lake Superior district is that made, in 1920, by Mr. R. C. Allen, amounting to 2,947,225,000 tons of assured and probable ore. This includes direct- shipping or so-called merchantable ores, and those capable of beneficiation by demonstrated processes. De- ducting from this the 287,000,000 tons shipped since 1920, leaves a present reserve of approximately 2,500,- 000,000 tons, or; about 50 years' supply. The assured ore in this estimate is given as 1,560,500,000 tons, which checks Mr. Lake's estimate of 1,528,948,000 tons, or about 30 years' supply. This is not a long time in the life of the steel industry, and it can be readily appreciated that the matter is important enough to war- rant the attention it is beginning to receive. The first question that engages our attention is, What is merchantable ore? In 1902 the average of all Mesabi shipments was 56.07 per cent iron and 4.35 per cent silica. Twenty-five years later it had dropped to 51.99 per cent iron, with silica up to 7.92 per cent. It has remained around these figures for' ten or twelve years and, except for a probable rise in silica, can stay there for an indefinite period. Most of these figures I am giving cover the Mesabi Range. Including the other ranges does not change the figures greatly, and the Mesabi Range commands the situation, since it produces about 65 per cent of the total annual tonnage and, according to Mr. Allen, contains 81 per cent of the assured reserves, 50 per cent of the probable reserves, and 66 per cent of both the assured and the probable reserves.

Jan 1, 1926

By John D. Morgan

Uncertain world conditions of the present time require that this country be prepared to meet: 1) all out nuclear war with attack on the U. S.; 2) limited wars; 3) political, economic, and/or pyschological warfare. Our present position as a major world power derives in large measure from our free institutions and great industrial productivity, and this productivity in turn depends on a continuing flow of raw materials-metals, minerals, fuels, and agricultural products. The U. S., with only about 6 pct of the world's population, uses from one to two thirds of the world's annual supplies of most metals and minerals. The U. S. strategic materials stockpiling program is designed to enhance our national security position: as stated in the preamble of the Stock Piling Act, to decrease and prevent wherever possible a dangerous and costly dependence upon foreign nations for supplies of strategic and critical materials in times of national emergency.

Jan 8, 1960