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By John Jermain Porter

PAGE. I. INtroduction............ 191 I1. Derivation of Formula foR Fuel-RequiRements.... 192 1. Heat Available in the Hearth........193 a. Method of Calculation..193 b. Data for the Determination of Critical Temperature.. 195 2. Heat Necessary in the Hearth ...... 197 a. To Care for Slag..197 b. To Care for Pig-Iron...198 c. To Reduce Silicon........198 d. For Other Items.........199 3. The Effects of Rate of Driving ..... 199 4. Loss of Carbon Between Throat and Hearth.....201 a. Solubility of Coke..201 b. Carbon-Loss Due to Flux....201 c. Effects of Reducibility of Ore..202 5. The Formula as Used........203 III. The LImitations of the Formula........ 204 1. Through Effects of Irregular Furnace-Work.....204 2. Through Ratio Between Heat-Requirements in Shaft and Hearth. 20.5 IV. The Formula Applied to Actual Furnace-Records,.. 209 1. Description of Furnace-Stock........ 209 2. Furnace Dam..........210 3. Application of Formula..211 4. Average Furnace-Practice..213 V. Sources of Error........... 214 VI. SuggesTions for Practical Methods of Fuel-Economy... 215 VII. Efficiency as a Factor in Furnace-Management.... 219 1. The Efficiency Principle........ 219 2. The Application to the Blast-Furnace..220 I. Introduction. The heat-balance of the blast-furnace has been a favorite subject for discussion for many years. and its study has contributed much to our knowledge. and still possesses a certain academic interest. As a means of accounting for differences in fuel-consumption, however. it has failed utterly. and it is evident that we must look elsewhere for the means of accomplishing this end.

Jan 1, 1912

By Michel Elle, John Chipman

The equilibrium of gaseous H20-H2 mixtures with liquid iron-columbium alloys in the range 0.2 to 2.4 pct Cb shows that the activity coefficient of oxygen is strongly diminished by Cb. The oxide in equilibvium with the melt is identified as CbO2. The equi-librium constant at 1600 deg C is [%Cb][fo. % 0]2 = 2.9 x 10-4 where log fo= —0.14 [%Cb]. The deoxidizing power is comparable to that of vanadium, COLUMBIUM (niobium) is finding increasing use as an alloying element in steel. It forms several stable oxides and is removed from the steel bath by oxidizing slags. The specific oxide formed in steel-making is not known although Sazanov snd Shvarts-man,' in their study of its partition between slag and metal, have assumed this to be Cb2O5 It is the purpose of this study to determine its deoxidation equilibrium at 1600°c, the nature of the oxide formed and the interaction between columbium and oxygen in the melt. The investigation was based on the reaction H2 + O=H2O; Kl=ph2o/(pH2[%O]) [1] in which 0 signifies oxygen dissolved in the liquid Fe-Cb alloy. The method and equipment of recent studies2,3 were utilized. In brief, the molten alloy, contained in a small crucible, is held in a controlled mixture of steam, hydrogen, and argon until equilibrium is reached. It is then cooled quickly in a stream of helium and analyzed for columbium and oxygen, the latter by vacuum fusion.4 The solubility of the oxide in liquid iron is determined by visual observation of scum formation on the surface of the melt. Crucibles of MgO proved unsatisfactory because of partial reduction at the metal interface. Pure A12O3 crucibles were heavily blackened by the melt and could not be used at high concentrations of columbium. Silica crucibles were more satisfactory but these introduced some silicon into the melt thus necessitating an uncertain but small correction for its effect on the activities of the other solutes. In silica it was possible to observe the scum formation when the melt became saturated and there was no apparent reaction between scum and crucible. The procedure for saturated melts was as follows. The alloy charge composed of electrolytic iron and columbium grain was melted and held at constant temperature. The gas ratio H2O:H2 was progressively increased by raising the saturator temperature until a point was reached at which a bright film appeared on the surface and covered it completely. This film could be dissolved by raising the temperature of the melt and it reappeared when the temperature was lowered. Under a partial film covering, utilizing bare areas for temperature measurement, the melt was brought to equilibrium with the atmosphere by holding at temperature for about 1 hr as suggested by Dastur.5 INTERACTION IN THE MELT Several experiments were made without columbium to establish a base in silica crucibles. The results are shown in Table I. Except for one run, they agreed well with Floridis1 comparable results in other crucibles. The value of log K1 is taken from Table I as 0.58. This is slightly larger than Floridis' result, probably because of less elaborate safeguards against thermal diffusion. Results obtained in the Fe-Cb-0 series in which no scum formed are shown in Table 11. The equilibrium ratio Kl is defined as ph2o/(ph2[%O]). It is related to the equilibrium constant K1 as follows:

Jan 1, 1962

By John Dasher

Extrapolation is a useful technique, but it can be overdone. Seldom is it justified to study over a range of 1 to 6 and extrapolate the results to 150,000. It is especially dangerous if the extrapolation is based on a false assumption. The authors assume settlers scale-up by residence time rather than by area, admit their result (a settler depth of 7 m) is "unreasonable" and suggest longer, wider, shallower settlers might be better. Various authors have noted for a copper-LIX system a total flow basis of 2 gpm per sq ft for sizing settlers. The results of this are compared with those in the paper in [Table 7]. The authors note that flooding of their settlers was never approached. Thus the smallest unit calculated is understandably twice too big. The largest however, is 5% of the required size. I note that the figures in [Table 6] for 1/min/cm2 are based on plan area rather than cross section as titled and are wrong by l0 4. A flow of 2050 1/min/cm2 is about Mach I. It is also 10 5/3 or 46.5 times that of the little one, although the abstract says the design was based on constant flow rate per unit cross section.

Jan 1, 1977

By C. M. Tucker, Kent R. Van Horn, W. P. Sykes

RECENT investigations of the molybdenum-carbon alloys have been reported by Becker and Ebert1‡, Westgren and Phragmén2, T. Takei3, and H. Tutiya4. Takei3 studied the Mo-C system by employing metallographic and X-ray methods, and the other publications described the determination of the crystal structure of the molybdenum carbides. In exploring this system by a technique previously applied to the tungsten-carbon series5, the results of Takei were confirmed with two definite exceptions; i.e., first the composition of the eutectic, and second the nature of the carbon-fish intermediate phase. Consequently, a more thorough examination of the molybdenum-carbon constitution was initiated in an effort to correlate the data supplied by the microstructures, diffraction patterns and chemical analyses. METALLOGRAPHIC INVESTIGATION A briquette of molybdenum powder when heated in a carburizing atmosphere at 1500° to 1600° C. for several hours develops the carbon-rich layer shown in Fig. 1. The carburization was accomplished by placing the briquette in a carbon tube, which was heated in the hydrogen atmosphere of an alundum muffle wound with tungsten resistor. While the macrostructure indicates two distinct shells, and suggests the possibility of two carbon-rich phases, no evidence of this condition could be detected by the microscope, which revealed but one high-carbon constituent. This carbide forms next to the molybdenum as a relatively

Jan 1, 1935

By George W. Maynard

(Pittsburg Meeting, March, 1910.) AT the Pittsburg meeting of the Institute, May, 1879, I made the first announcement in America of the results obtained by Sidney Gilchrist Thomas and Percy C. Gilchrist, ill their efforts to eliminate phosphorus in the manufacture of steel in the Bessemer converter and the open-hearth furnace.1 The first published statement in an American newspaper was a reprint of the first Thomas-Gilchrist paper, 2 which I sent to J. C. Bayles, at that time the editor. At the suggestion of many friends who were present at the Pittsburg meeting, and others who are cognizant of the beginnings of the process in the United States, and for the information of the younger generation of the iron and steel fraternity, I have thought it eminently proper that the history of the process in detail should be given where I made the first announcement and where the process has had its largest development. During my residence in England, from April, 1873, to February, 1879, and as a member of the Iron and Steel Institute since 1874, I was present at many of its meetings during those years. At nearly -every meeting the burden of discussion was the question of the use of pig-iron containing phosphorus in the. manufacture of steel by the Bessemer or the open-hearth process. In my biographical notice of Thomas;3 read at the New York meeting of, the Institute, February, 1885, I show that the working-out of the process was not a hap-hazard or accidental inspiration, but the culmination of many years of investigation of experiments and theories which had been carried on and advanced by chemists and metallurgists at home and abroad. 1 Trans., viii., .5 (1879-80). 2 The Iron Age, vol. 22, No. 17, p. 3 (Oct. 24, 1878). 3 Trans.. xiii., 785 to 791.

Jul 1, 1910

By C. H. Frick

BEFORE presenting the main topic, as indicated by the title, this paper will give some of the high-spot history of the anthracite industry. INTRODUCTION The earliest recorded use of anthracite was in the year 1762, when a company of Connecticut pioneers discovered anthracite near the present city of Wilkes-Barre, Pennsylvania. In the early days of the industry, the coal was used only in large pieces, the smaller pieces being discarded to waste piles. As the output of the industry increased during the nineteenth century, uses were developed for somewhat smaller sizes down to and including pea coal. Early in the twentieth century, sizes smaller than pea, such as No. I and No. 2 buckwheat, were developed and used. Accu¬mulations of piles from current mining operations were still increasing; that is, the smaller sizes were still being discarded. It was not until after World War I that preparation of the so-called steam sizes began commercially. This was largely No. 3 buckwheat, which is screened through a 3f 6-in. round-hole screen and over a 332-in. or a M 6-in. round-hole screen. USE OF SMALLER SIZES The earliest recorded experience in burning the small sizes of anthracite for steam production, other than in a previous small experiment, was in the year 1913, when a size known as "boiler fuel" was introduced-a mixture of rice and barley (No. 2 and No. 3 buckwheat). At that time, there was still no method known for burning the still smaller sizes. TABLE I.-Screen Sizes Used for Small Sizes of Anthracite [ ] At the present time, various sizes down to and including No. 5 buckwheat are being prepared (Table I) from current mining and bank-reclaiming operations. The sizes of No. 4 and No. 5 buckwheat and smaller are generally being used for steam production in large boilers. The Pennsylvania Power and Light Co., following World War I, used 680,000 tons of anthracite per year, burned largely on stokers for production of steam, whereas for the year 1943 it used 1,940,000 tons of stoker sizes and 400,000 tons of smaller sizes for grinding and burning in pulverized form. This company has taken a very large part in the research and development of ways and means of burning these smaller sizes of anthracite, including the grinding of the very small sizes. This paper is particularly concerned with the latter feature.

Jan 1, 1946

By William C. Hagel

Oxygen-18 exchange between gaseous oxygen, held at a pressure of 125 mm Hg in a PL-IORh chamber, and splzeres of a Fe2O3 containing three or less grains was determined from 9000 to 1250°C. Isotope equilibrum on crystal surfaces appears to be quickly established, and the rate-determining factor is self-difiusion confbvrning to the relation D = 2.04 esp(- 77,900/RT) sq cin sec-'. Changing sphere diameters caused no detectable variation in diffusion coefficients. Oxygen ions diffuse faster than cations at low temperatures, but a crossover may occur at about 1150°C. INVESTIGATIONS by Davies et al.' and Himmel et al2 have suggested that the mechanism of iron oxidation above 600°C involves a predominance of cation migration in the wüstite (FeO) and magnetite (Fe301) layers and oxygen-ion migration in the hematite (a Fe2O3) layer. Evidence for little cation migration during hematite growth consists of: 1) the disappearance of radioactive-silver markers, presumed to vaporize from the oxide-gas interface, and 2) a large discrepancy between parabolic rate constants for magnetite oxidation and those calculated from Lindner's3 data for cation self-diffusion, D:, using Wagner's theory.4 Reversing the calculations gave anticipated self-diffusion coefficients, D:, for oxygen ions of 3.6 x 10-9 sq cm sec-1 at 1100°C and 5.9 x 10-10 sq cm sec-1 at 1000°C. Since then Kingery et a1.5 reported three values for oxygen-ion diffusion in polycrystalline, sintered hematite. These were obtained near 1200°C, at an oxygen pressure of approximately 150 mm Hg, and could be represented by the Arrhenius expression, Dg = 1 x 10 11 exp(-146,000/RT) sq cm sec-1. Extrapolation to temperatures below 1100°C infers that oxygen ions are less mobile than cations. This contradicts the aforementioned oxidation evidence and also coble7s study of the initial sintering of hematite. From the latter, apparent diffusion coefficients for the slowest rate-controlling species could be calculated, and fair agreement was found with an extension of Lindner's data for cation diffusion. Fig. 1 depicts such comparisons graphically. Three points have been included for the determinations of Himmel et al. on cation diffusion in large, natural hematite crystals surrounded by pure oxygen at atmospheric pressure. No dependence on crystal log raphic direction was noted. Since the value of 10-l4 sq cm sec-' at 1000°C actually represents an upper limit, one might interpret that there is a small decrease in D: when single crystals are employed. On the whole, however, cation diffusion appears relatively well-defined,* while the few results tension to lower temperatures. After having gained experience measuring oxygen-ion diffusion in certain glasses7 and in the corundum oxide, a Cr2O3, the purpose of this work was to determine D; values for hematite and thus possibly assist a mechanistic understanding of the kinetics of the oxidation and reduction of solid iron oxides. I) EXPERIMENTAL PROCEDURE A) Material. Hematite powder of moderately high purity was received from the Columbian Carbon Co. An accompanying lot analysis listed 0.03 H2O, 0.008 weight percents, with the remainder Fe2O3. Subsequent treatments were ball milling, drying, prepressing, and hot-pressing for 60 min at 1350°C under 5000 psi. Since graphite dies coated with a slurry of alumina were used for hot-pressing, the surrounding atmosphere at temperature was sufficiently reducing to form some magnetite on the outer surface of each cylinder. After removing any attached alumina, a stabilizing anneal of 50 hr at 1300°C in oxygen was added. The final product was nonmagnetic and exceeded 97 pct of the density (5.24 g cm-3) usually given for FezO3. On polishing cylindrical ends, counts were made of the number of grain boundary intercepts per

Jan 1, 1967

By E. J. Rapperport, M. F. Smith

A presentation of the W-Ru constitution diagram is given. Techniques utilized in the determination of phase boundary values include electron micro-probe analysis of two-phased alloys and diffusion couples, as well as normal metallographic and X-ray methods. The primary features of the diagram are: 1) a terminal solid solution of ruthenium in tungsten with a maximum solubility of 23 at. pct Ru at 2300°C; 2) a terminal solid solution of tungsten in ruthenium with a maximum solubility of 48 at. pct W at 2205°C; 3) a o phase of maximum breadth about 6 at. pct based on the composition W3Ru2 which forms peritectically from the melt at 2300°C, and which decomposes eutectoidally at 1667 °C to form a twigs ten and 0 ruthenium; 4) a eutectic at 45 at. pct Ru and 2205°C with the products being o plus ß ruthenium. THE W-Ru diagram has previously been studied only in a cursory fashion. Raub and alter' obtained a 1400°C isotherm in which they observed no intermediate phases, and on which they established the limits of solubility as 36.5 at. pct W in ruthenium and about 1.5 at. pct Ru in tungsten. In addition, Obrowski2 found a o phase forming peritectically from the melt and existing only above 1650°C. Below this temperature the phase was presumed to decompose eutectoidally. The present work finds the diagram as given in Fig. 1. I) EXPERIMENTAL PROCEDURE The materials used for alloy preparation in determining the W-Ru constitution diagram were 99.9 pct pure ruthenium powder supplied by Baker Chemical Co., and 99.9 pct pure tungsten powder from General Electric Co. Typical analyses of these elements are given in Table I. Initial alloys at 10 at. pct intervals were prepared from the metal powders by the following method. Powders sufficient for 25 g of the alloys were weighed out with an accuracy of 0.1 mg and blended mechanically. After blending, the powders were compacted, in a steel die, at approximately 30,000 psi. The compacts were sintered in an electric vacuum furnace in order to remove adsorbed gases and to achieve partial densification prior to arc-melting. Vacua of 10-4 mm Hg or less were maintained in sintering as the furnace temperature was raised to approximately 2000°C. Sintering times ranged from 10 to 20 hr. The sintered compacts were arc-melted under a protective atmosphere of purified helium. Melting was conducted on a water-cooled copper hearth, utilizing a nonconsumable tungsten electrode. In the melting process, each alloy was turned over and re-melted on opposite sides from four to six times to ensure complete melting and to eliminate gross in-homogeneities. The arc-melter used had a vacuum capability of 5 X 10-6 mm Hg, and a leak rate of about 20 -liters per hr. Chemical analysis techniques for refractory metal-platinum group metal combinations are not well-established; therefore, composition control and determination depended principally upon weight-loss observations and calculations. This consisted in weighing each alloy after sintering and after arc-melting, and calculating the maximum and minimum composition values, assuming the total weight losses to be first all tungsten, and then all ruthenium. Since composition uncertainty was directly related to weight loss, care was taken to minimize losses in handling, compacting, and melting. Prior to homogenization and equilibration the as-arc-melted alloys were analyzed in several

Jan 1, 1964

By N. A. Gokcen, S. Fujishiro

THE pressures of Mn(g) in equilibrium with Mn7C3 and graphite have been measured by McCabe and Hudson' and Butler, McCabe, and paxton2 by means of graphite, zirconia, and Ta-Mo Knudsen cells. The details of corrections in their measurements were somewhat different from those of the authors;3'4 hence, further independent results at higher temperatures seemed to be warranted. The stoichiom-etry of Mn7C3 in equilibrium with graphite and its stability up to the vicinity of 1373 °K have been satisfactorily established by Kuo and persson5 (See also Hansen and Anderko).' The method of investigation has been described elsewhere in detail.3'4 The carbide was prepared in the manner described by McCabe and Hudson. In order to avoid possible reactions with refractory oxides, only graphite cells were used for the effusion experiments. The authors' results are the runs M-1, M-2 and M-3 listed in Table I, together with those of McCabe and co-workers. The heat capacity, c;, of Mn7C3 is not known; therefore McCable et al. plotted their data as log P vs 1/T and the results were only expressed first' as, and later2 as logP=- -14220+6.06 without further thermodynamic calculations. However, it is possible to estimate closely the necessary heat capacity as follows: When H; - &98 of CrC, or MnO, is plotted vs x, corresponding to various compounds, with temperature as the parameter, it is seen that the relationship is represented by a line of very small curvature. This relationship is also followed by other compounds which do not exhibit solid state phase transformations. In view of the fact that chromium and manganese have the atomic numbers of 24 and 25 respectively, it is reasonable to assume that H; - H;ae vs x for MnC, follows the same type of lines as those for CrC, for which adequate data are available.7 Similar correlations appear to be valid for oxides of two neighboring metals for which reliable data are available. The procedure is thus to move the lines for CrC, vertically (parallel to the axis of HT - H298) until they coincide with the points for MnC1/3, the only carbide of manganese whose H; - HO298 has been

Jan 1, 1963

By Lauren A. Wright, A. E. J. Engel

Under the designations "industrial talc" and "soapstone" are included earth materials of widely different chemical and mineral compositions. Talc, the mineral, is a hydrous magnesium silicate, with a suggested theoretical formula H2Mg3(SiO3)4 or H2O.3MgO.4SiO2, which postulates 63.5 pct SiO2, 31.7 pct MgO, and 4.8 pct H20.18 Single grains or leaves of talc, however, seem to have variations in water content that range from 3.5 pct to more than 7 pct, as well as slight differences in the proportions of MgO and Si02.20 Most of the industrial talcs produced in the United States do not approach the composition given above (see Table 1), but are essen- [ ]

Jan 1, 1960

By Charles H. Kline

Industrial minerals are the Cinderella of the mining I industry. Often considered as just dirt by traditional hard-rock miners and oil drillers, these products nonetheless comprise the second largest segment of the industry and the fastest-growing one. With annual sales of $5.7 billion, industrial minerals make up 22% of the dollar value of U.S. mineral consumption. By contrast, metals account for only 11%. Fuels, of course, are dominant, representing 67%. The dollar values of production and consumption for the three segments of the industry in 1968 are shown in Table I. The growth rate of industrial minerals is shown in Table II. From 1953-1968, the current-dollar value of all U.S. mineral production increased at the average annual rate of 3.8% while that of the gross national product increased at 5.9%. Industrial minerals are the only segment of the mining industry that approached the growth of the overall economy in this period, with production values increasing 5.1% a year and apparent-consumption values 5.6% These data, expressed in current dollars, include the effects of inflation. The growth in U.S. industrial minerals production is even more striking when expressed in indexes of physical production. As shown in Table III, production of all U.S. industries increased by 4.1% a year from 1953 to 1968. The growth in production of stone and earth minerals just matched this figure. By contrast, the average annual increase for oil and gas was 2.2%: for metals, 1.6% : and for coal, only 0.6 %.

Jan 1, 1970

R. S. Shoemaker: Our first question is, is there a need for a grizzly before a primary crusher? What is its effect on crusher capacity and crusher maintenance? Is it worth the extra capital cost in a crusher installation? Vincent: ASARCO has a grizzly at Mission. Utah Copper uses grizzlies ahead of their gyratories. There is some quite abrasive ore at Mission, an argillite type of rock, which has a work index of 16.5 to 20, which is getting up toward the taconite classification. We get a life of 12- 16 million tons per set of concaves or per mantle with the grizzly ahead of the crusher. At Duval Corp., some 6 miles to the south of Mission, their crusher installation on a good, hard rock does not have a grizzly, and the last information I had is they get a life of about 2 ½ -3 million tons on their mantle and concave. At Silver Bell, our other copper unit in Arizona, they do not have a grizzly ahead of the gyratory and there they get a life of about 5-6 million tons. At Utah Copper, which we all know is a fairly soft ore, relatively speaking, they get a life of 24-27 million tons with grizzlies ahead of the crushers. I think a grizzly has a very definite effect on the life of the mantle and the concaves. As far as a jaw crusher is concerned, I think that usually it is desirable to have a grizzly if it is properly designed, which means it is self- cleaning. Otherwise I would not like to see one in the circuit.

Jan 9, 1967

By Claus G. Goetzel

PRESSING of powdered metal parts is best done in the direction of the shortest extension of the piece, to avoid too great a loss of pressing force through internal [ ] friction. As long as curved surfaces, recesses, or offsets occur only parallel to this shortest axis of pressure, no special difficulties arise: the cross sections, perpendicular to the pressure, do not vary, nor does the shape of the parts change during compression except for a gradually reduced thickness (Fig. IA). The problem becomes more difficult, however, when the curved surfaces or recesses are perpendicular to the shortest axis of the part (Fig. IB). Two processes for molding uniformly dense parts with complicated shapes from powdered metals are described in detail in this paper. Both can be employed successfully by those trained in the art. The first refers to curved parts; the second is especially adapted to parts having one or more recesses or steps. Both methods, as set forth here, are applied under the condition that presents the more difficult problem. For clarity, before description of the two practical methods, the variable factors in molding powdered metal parts will be reviewed, then an idealized procedure will be considered briefly. VARIABLE FACTORS IN MOLDING POWDERED METAL PARTS Compression Ratio Compression ratio is defined as the proportion of the final relative density of the compact to the apparent density of the powder. For iron powder of an apparent density of 3.0, for example, a compression ratio of 2 1/2 : I would be required to produce a compressed compact of 7.5 density; whereas for another iron powder having an apparent density of only I.5, a compression ratio of 5:I would be required to produce the same density. The lower the powder's apparent density, the greater must be the compression ratio for pressing compacts of high density.

Jan 1, 1945

By Lawrence Addicks

THrough the courtesy of Dr. James Douglas I am permitted to give a summary of some of the results obtained in leaching slimes tailings in a series of experiments conducted under my direction at Douglas, Ariz., during the past year. While the test run for which the data are given deals with a particular case, much of the work is general in its application and may therefore be of interest. This work was done upon the ores of the Burro Mountain Copper CO. A description of the geology of the district will be found in the paper by R. E. Somers published in this volume, p. 604. The mineral is pyrite and chalcocite very finely disseminated throughout the gangue and a characteristic of all the ores is the large amount of alumina present. A representative analysis of the particular ore under consideration would be about as follows: Cu, per cent..................... 2.35 S, per cent...................... 3.0 Ag, ounces per ton.............. 0.05 CaO, per cent.................. 0.5 Au............................ None K2O, per cent.................... 4.0 Fe, per cent..................... 1.50 SiO², per cent.................... 70.0 Alz²O³, per cent....................13.OO The leaching of the ore direct was early dismissed from consideration for the following reasons: 1. The ore would have to be quite finely crushed to liberate the mineral for leaching; concentrating after crushing would cost but a few cents a ton; and a higher total reeovery would result from leaching tailings rather than ore. 2. Rough concentration would yield a suitable material for roasting to make sulphur dioxide or sulphuric acid in connection with the leaching scheme. 3. Such a program put the question of cost vs. recovery on a basis where flotation and discarding of tailings were directly comparable. Concentrating experiments already available indicated that the tail-

Jan 1, 1916

CONTENTS PAGE ZAPFFE, CARL.-Manganiferous Iron Ores of the Cuyuna District, Minnesota. Discussed by A. K. Knickerbocker 1 MCCORMACK, C. P.-Economics of the Cuyuna Manganiferous Iron Ores. Dis-cussed by T. L. Joseph, J. Wilbur Van Evera, C. P. Perin, T. T. Read, L. E. Ives 4 READ, T. T.-Probable Error in Blast-furnace Records and Calculations Therefrom. Discussed by C. H. Herty, Jr., T. T. Read, T. L. Joseph, Ralph H. Sweetser 8 SCHWARTZ, H. A. and HIRD, (Mrs.) ANNA NICHOLSON.-Chemical Equilibria During Solidification and Cooling of White Cast Iron. Discussed by N. B. Pilling, Ralph H. Sweetser, H. M. Boylston, Albert Sauveur 10 HERTY, C. H., JR., BELYEA, A. R., BURKHART, E. H., and MILLER, C. C.-Some Factors Affecting the Elimination of Sulfur in the Basic Open-hearth Process. Discussed by Henry D. Hibbard, L. F. Reinartz,. C. H. Herty, Jr., Ancel St. John, A. L. Feild, C. R. Hayward, Ralph H. Sweetser, C. D. King, Haakon Styri, George A. Orrok 12 HIBBARD, HENRY D.-Finishing Melting Temperatures of Simple Ingot Steels. Discussed by Haakon Styri, George V. Luerssen, A. G. Zimermann, A. L. Feild, George A. Orrok, Albert Sauveur, R. F. Harrington, Henry D. Hibbard, I. A. Billiar, William J. Priestley, H. W. Gillett, W. P. Barba, Jerome Strauss, Harry H. Smith, H. LeChatelier, L. F. Reinartz 19 HERTY, C. H., JR., and TRUE, O. S.-The Reaction between Manganese and Iron Sulfide. Discussed by A. L. Field, H. S. Rawdon, C. H. Herty, Jr., T. L. Joseph, Haakon Styri 37 KAMURA, HEIHACHi.-Reduction of Iron Ores by Carbon Monoxide. Discussed by T. L. Joseph, R. Franchot, Ralph H. Sweetser, C. H. Herty, Jr 43 JOSEPH, T. L.-Effect of Sulfur on Blast-furnace Process. Discussed by R. Franchot, C. A. Meissner, T. L. Joseph, C. H. Herty, Jr., Ralph H. Sweetser, I. E. Waechter, F. N. Speller, T. T. Read 45 GOOSTRAY, JOB, HARRINGTON, R. F., and HOSMER, M. A.-Brief History of Metallurgical Practice in Cannon-making with Particular Reference to the Cast-iron Gun. Discussed by A. G. Zimermann, Geo. A. Orrok, Chas. Me-Knight, Jr., F. Brauer 51 Manganiferous Iron Ores of the Cuyuna District, Minnesota Discussion of the paper of CARL ZAPFFE, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1390-I, with MINING AND METALLURGY, December, 1924. A. K. KNICKERBOCKER,* Virginia, Minn. (written discussion).¬The author makes a broad distinction between the "black" ores (the

Jan 6, 1925

By J. W. Marx

A method is given for predicting the complete gravity drainage characteristics of arbitrarily long columns from centrifuge drainage measurements on reconstituted core samples. Oil residuals corresponding to hundreds of years of normal gravity depletion can be obtained in a few hours on the centrifuge. The gravity flow rate at any stage of the depletion process may be determined from the time correlation derived, and experimentally checked, in this study. INTRODUCTION Apart from the original observations of Muskat et al1, research publications2,3,4 on the subject of gravity drainage have been largely concerned with establishing in detail the saturation, S as a function of the height, z, in a draining column at any given time, t. Some form of numerical integration must be employed to obtain production rates and cumulative production even when S(z, t) is known. Furthermore, the relevant experimental work has been concentrated on drainage of a single wetting liquid from unconsolidated media. Since oil production usually concerns the drainage of a partially wetting liquid from consolidated media, in the presence of connate water, and since it is unlikely that sufficient information exists to establish S(z, t) in detail for any natural reservoir, the published research work appears to be, at best, only qualitatively applicable to production problems. With this in mind, the present study was undertaken by the writer. Experiments were planned whose results would have two advantages over existing measurements: 1. Observations were to be made on specific reservoir rock, reconstituted with formation water and formation oil. This would reduce their generality, from the research viewpoint, but increase their utility for production purposes. 2. The measurements were to be self-integrating, i.e., the phenomena were to be described and interpreted in terms of cumulative results. THEORETICAL DEVELOPMENT It was commonly known that centrifuging a liquid bearing porous medium increases the drainage rates and minimizes capillary end effects. The specific problem lay in selecting an acceleration, a, such that the mean residual saturation of a model cylinder was equal to the residual saturation of an arbitrarily long prototype column when the latter was drained by earth gravity alone. The physical conditions required to permit a valid scaling of model drainage time, tm with prototype drainage time, t, may be stated as follows: (a) At t = tm = O, So = Smo; (b) At t = tm? 8 Sr. = Smr.; (c) For all intermediate values of t and dS/dt=dsm/dtm whenever S = Sm; (d) S(z) = Sm(z) = a constant when t = tm = 0. 1 Here S = T I S(z)dz, where h is the length of the « Jo cylindrical column being drained and the subscripts S,Sm, and refer to model, initial, and residual systems, respectively. The first three conditions mean, simply, that an 3 vs t plot will be numerically identical with an S, vs t, plot,

Jan 1, 1957

By J. N. Ong

The oxidation of tantalum is assumed to occur by four simultaneous first-order chain reactions; solution of oxygen in the metal, nucleation and growth of a suboxide phase at the metal surface and two phase boundary processes which give rise to two different modifications of Ta2O5. A rate equation is then formulated which accounts for all principal details of oxidation behavior, unifies and correlatss the results of the principal investigations, and expresses the rate as a function of pressure, temperature, and time. For purposes of practical application, the expressions: may be used below and above 700T respectively to determine the regression rate of tantalum in cm per hr, where T is to be expressed in "K and P in atmospheres pressure of oxygm. The equations will reproduce within a factor of two all reported experimental rates in the temperature range 475" to 1400°C and pressure range 0.000026 to 40.8 atm 0. 1 HE oxidation kinetics of tantalum have been investigated thoroughly in the temperature range 50" to 1400 and pressure range 1.32 x l0-' to 40.8 atm pressure of 0,and as a result, the principal features of the oxidation of tantalum are known and have been described in considerable detail. The exposition of the characteristics of the behavior of tantalum in oxygen has been largely descriptive, with considerable attention being devoted to elucidating the structure, composition, and morphology of the resulting oxide products. The weight change vs time results have usually been reported graphically. With the exception of the linear rate below 700 C and the process of diffusion of interstitial oxygen into the metal,6'9 no effort has been made to characterize the reaction rates in functional form. It is the purpose of this paper to demonstrate that when the fundamental principles of chemical kinetics are rigorously followed, the results of the principal investigations will be correlated and unified and the oxidation rale may be expressed as an analytic function of pressure, temperature, and time. In addition to accounting for the temperature and pressure dependency of the oxidation rate, the following minor features will be accounted for as a result of the basic analysis: the initial period of nonline-arity in rate at low temperatures, which decreases with increasing temperature;3'5'7 the rate vs temperature cusps obtained at constant pressure"5 the concentration gradient of oxygen interstitially dissolved in the metal.5'7 The analysis will also be consistent with the overall chemistry of reaction and with all visual, microscopic, and X-ray observations. DEVELOPMENT OF RATE EQUATION As a fundamental basis for the treatment of metal-oxygen reaction kinetics, it will be regarded that the rate of reaction is determined by the concentration and not the activity or chemical potential. It is further assumed that all metal-oxygen reactions are first order complex chain reactions" whose rate is dependent on the concentration of an intermediate species which is a complex function of the oxygen concentration, or oxygen pressure, only. The basic rate equation is therefore: is the weight of oxygen consumed by the reaction, A is that portion of the area of the metal over which the reaction is occurring (cm2), t the time (sec), kf the rate constant for forward reaction, C the intermediate species concentration and f '([Oz]) and f (Po,) are complex functions of oxygen concentration and Oxygen pressure respectively. Reverse reactions may usually be neglected in metal-oxygen systems since a large negative free energy generally accompanies these reactions. Eq. [I] takes different forms when the rate of reaction is controlled by diffusion into or through a phase or at a phase boundary. For diffusion into the metal phase, the rate is given by1' Di is the diffusion coefficient of species diffusing into the metal phase (cm2/sec), and Q is the corre-

Jan 1, 1962

By J. E. Burke

RECENT investigations have elucidated many of the phenomena of the grain growth process, but have also revealed some conflicting and unexplained results. Beck and his co-workers1,2,3 have shown that grain growth continues with continued heating at one temperature until the average grain size approaches the thickness of the specimen, Plotting the logarithm of the average grain diameter, D, against the logarithm of the annealing time, t, they find the straight line relationship given by the equation: [D=Ktn [11] with possible small deviations at short annealing times. K and n are constants at constant temperature. On the other hand, Walker4 finds that, in alpha brass, the rate of growth falls off more rapidly than indicated by Eq I after long annealing, so that an equilibrium grain size is approached. Burke5 showed, using Walker's data, that time and temperature for grain growth are apparently related through an activation energy, H, according to the relationship: [t, Hr i '_ III t„ = R \T, - ~) [2]] where t1 and t2 are the annealing times necessary for the average grain size to increase from Do to D at temperatures T1 and T2 and R is the gas laws constant. In the case quoted, H had the value 60,000 cal per mol. The apparent validity of this relationship, at least up to 700°C, and the approximate value of H were later confirmed by Beck.' The results obtained by Beck, Kremer, Demer and Holzworth2 for aluminum and aluminum-magnesium alloys could not be satisfied by such a relationship, since the slope of the isothermal curves increased with increasing temperature. These data indicate and Beck, Holzworth and Hu6 later demonstrated experimentally that the only apparent factor controlling the rate of grain growth at constant temperature is the grain size. While many of the phenomena have been elucidated, a reasonably quantitative explanation of the process is lacking. There exists uncertainty even as to the primary driving force for grain growth, although there is a considerable body of indirect evidence that the interfacial energy of the grain boundary is responsible.7,8,10 Making implicit use of this assumption, several authors14,15 have pointed out that grain boundaries should migrate toward their center of curvature. Harker and Parker' have advanced this concept furthest, and show that one can expect grain boundary migration to occur only when the grain faces are curved, or when they meet at non-equilibrium angles. When the face is curved toward a grain A, for example, the atoms in the surface of grain B, on the other side of the boundary, are on the average more surrounded by the atoms of their lattice than the atoms on the surface of grain A. Because of thermal motion, the atoms at the interface will sometimes be attached to grain A and

Jan 1, 1948

Discussion of the paper of DWIGHT T. FARNHAM, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2357 to 2364. DAVID T. DAY, Washington, D. C.-Do you know anything about the character of that clay as to organic matter? H. RIES, Ithaca, N. Y.-No; it is a dark brownish clay, sandy in its nature. The brownish coloring is probably due to organic matter. Some lignite is also present. DONALD W. Ross.*-I have worked at the plant under consideration. I have not seen Mr. Farnham's paper; but in answering the question as to the organic matter, I might say there is practically no organic material scattered through the shale. There are, however, several layers of carbonaceous shale and rather low-grade coal interbedded with the formation. There are two very serious drawbacks-one which threatens to shut down the plant and another which merely means the expenditure of money. The first is taking care of the sediment from the washing away of the overburden. The government is doing extensive work at different points about Lake Washington with a view to creating a fresh-water harbor for Seattle. I understand that they keep at the Denny-Renton people to keep the channel of Cedar River clear. The Denny-Renton Co. can hardly help filling up the channel so long as they continue their hydraulic work, so this is probably one of their most serious problems. The other is this: There is a large percentage of what I should call micaceous shale or sandstone-a sandstone which contains a large amount of light-colored mica. Of course only a limited amount of this can be used in the manufacture of paving brick. As they shoot down the bank after the overburden of gravel and loam is washed away, these large boulders of micaceous sandstone come down. The strata have apparently been crushed where the clay pit is located so that the exact formation cannot be readily determined. These pieces of sandstone, 5 or 6 ft. in diameter, have to be blasted and removed from the shale. They bother both in the open pit and in the tunnel mining. In the tunnel mining of the shale blocks frequently cover the holes in the roof of the tunnel through which the shale is loaded into cars.

Jan 4, 1915

By K. R. Garr, D. Kramer, A. G. Pard

EXPOSURE of steels to a fast-neutron flux results in helium generation by (n,a) reactions. The elements Fe, Ni, Cr, and N are major participants in the (n,a) reaction and helium concentrations of up to 5 x 10"5 atom fraction could accrue in fuel clads after a year of service in proposed fast reactors.' Such concentrations of helium can severely reduce the ductility of alloys at temperatures of reactor service. The phenomenon of helium embrittlement has been studied in austenitic alloys which were irradiated with particles as a rapid means of producing significant helium concentrations.2-5 The pres-ent work is a continuation of those studies and is concerned with helium effects in a ferritic stainless steel. I) EXPERIMENT Small sheet tensile samples with a gage length of 0.50 in. and a cross-section of 0.009 by 0.040 in. in the gage length were punched from cold-rolled type 405 stainless steel. The composition of the steel used in this work is given in Table I. Prior to helium injection, the samples were annealed 24 hr at 760°C which caused complete recrys-tallization with a resulting grain size of 40 u. This treatment rendered the alloy completely ferritic and carbide particles, 0.5 to 2 uin size, were present at a density of 1 x 1011 cm-3, Fig. 1. These carbide particles were probably a mixture of the M7C3 and M4C types.6 Helium was injected into the samples by irradiation with a particles from a cyclotron, which produced uniform concentrations through the center two-thirds of the sample thickness. Details of this procedure were previously described.' The average helium concentration, as measured on a gas-source mass spec- 11) RESULTS A) Tensile Tests. The results of the tensile tests are given in Table I1 where the values shown are averages of two samples. There was no significant effect of helium on either the yield strength or tensile strength at 550" or 650°C but an increase in both is apparent at 750°C. Samples with helium showed a 20 pct loss in total elongation at 650°C which increased to a 55 pct loss at 750°C. The uniform elongation is not affected by helium at 550" or 650°C but shows an increase at 750°C.

Jan 1, 1970