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By Walter W. Bradley

Mining by hydraulic process of the important gold-bearing gravels of the Sacramento Valley in the basins of the Yuba, Bear and American rivers began in 1853, and continued at an ever-increasing rate for 30 years. In its most active days it reached an annual production of $15,000,000, and averaged $10,000,000 per year over the 30 years. During that period no provisions were made to prevent the debris from being discharged into the water courses, and ultimately large quantities of silt, sand and gravel were washed down to the lower valleys; filling channels, causing overflow of agricultural lands and difficulty in maintaining navigable depths in the Sacramento River. Agitation and suits filed because of these damages finally resulted in the injunction decision of Judge L. B. Sawyer,' in the U.S. Circuit Court, Jan. 23, 1884, which closed down practically all hydraulic mining operations not having means to restrain their debris. In 1893 (approved March 1, 1893), Congress passed the act introduced by Representative Anthony Caminetti, of California, creating the California Debris Commission, composed of three officers assigned from the Engineer Corps of the U.S. Army, and since that time it has been legal and possible within the drainage systems of Sacramento and San Joaquin rivers to conduct hydraulic mining of gold-bearing gravels behind dams built under this commission's permit and supervision. In the watersheds of the Trinity and Klamath rivers, which flow directly to the Pacific Ocean and do not affect navigation or agriculture, operating permits from the California Debris Commission are not required. There is a measure of restriction there, however, through what is known as the Trinity and Klamath River Fish and Game District. Chap. 215, Stat. 1931, in order to secure relatively clear water for the fishing season, provides that between July 15 and October 15 each year there must not be discharged into these rivers debris that will cause a turbidity greater than a content of 50 parts per million in the

Jan 1, 1937

By R. D. Nelson

The purpose of this technical note is to briefly present some data on a phenomenon—recrystallization with concurrent deformation—that has been found to occur in a plutonium. This phenomenon is unusual because a plutonium is considered brittle, not easily deformed, and not easily recrystallized; the a phase is simple monoclinic having 8 atoms per unit cell and it is stable below about 115°C. The properties of the recrystallized metal were different from the as-cast metal. Even though a plutonium is difficult to deform, Ianniello successfully rolled it' and he also observed some recrystallization at 120°C.2 Pavlick and Hanson3 detected some recovery at 109°C but they observed no recrystallization. Gardner4 and Bronisz5 studied the compression properties up to 100°C but they did not report having seen recrystallization. In the present deformation studies of electrorefined plutonium pronounced recrystallization took place concurrently with plastic deformation in compression between 24" and 115°C. The metal contained less than 300 ppm total impurities with the major impurities being 100 ppm Am, 30 ppm C, 40 ppm W, and 25 ppm U; all other impurities totaled less than 100 ppm. The compression specimens were machined to dimensions of 1.2 cm long and 0.8 cm diam from as-cast rods having a density of 19.65 g per cu cm. They were heated to the test temperature in a high-temperature silicone fluid that was evacuated to 10-4 Torr. With this procedure the specimens oxidized a negligible amount, and the temperature was maintained within ±0.2°C for times up to 3 weeks. Deformation and recrystallization

Jan 1, 1969

By J. P. Murphy, T. E. Leontis

DURING the last few years, the trend in the aircraft and automotive industries has been toward higher and higher operating engine temperatures. This has created considerable interest in the effect of temperature on the properties of alloys. In the magnesium field, it has been recognized for many years that the addition of cerium imparts high strength and good resistance to creep at elevated temperatures. Beck,1 in his treatise on-magnesium, has summarized the work of German investigators. This includes the unpublished data of Menking, showing the increase in strength and hardness of extruded alloys containing 2 to 20 per cent Ce at temperatures from 200 to 300°C. (68° to 572°F.) and the results of Vosskühler, who demonstrated the improved resistance to creep of alloys containing 6 per cent Ce plus 2 per cent Mn and 0.5 per cent Ce plus 2 per cent Mn at 150°C. (302°F.). Wellinger and Keil2 have also reported the creep properties of a forged magnesium-cerium-manganese alloy at 200° and 250°C. (392° and 482°F.). Haughton and Prytherch have determined the tensile properties of various forged magnesium alloys containing cerium, cerium plus manganese, cerium plus calcium, cerium plus nickel, cerium plus nickel plus manganese, and cerium plus cobalt plus manganese at temperatures up to 290°C. (554°F.). Magnesium-cerium alloys have been used in some commercial applications. It is reported that an alloy containing 3 per cent Ce plus 0.5 per cent Mn plus 0.5 per cent Ca is being used on a forged impeller in Great Britain. Two forged parts made from an alloy with a nominal composition of 5 per cent Ce and 2 percent Mn have been found on the German .BMW-801D aircraft engine. These two forgings consist of a supercharger impeller and a rear cam-follower guide. In this country, several types of pistons have been made experimentally in both .the cast and the forged conditions from an alloy containing 6 per cent Ce plus 2 per, cent Mn and in the cast condition from an alloy of magnesium plus 10 per cent Ce. The cast pistons have been tested in various types of internal-combustion engines, with promising results. This paper presents the results of an extensive investigation on the properties of various cerium-containing magnesium alloys in both the cast and the forged conditions. Data are presented to show the beneficial effects of increasing amounts of cerium on the mechanical properties of magnesium at elevated temperatures. The effects of heat-treatment on the properties of these alloys and the attendant changes in the microstructure are discussed. The

Jan 1, 1946

By Charles Maier

IT has long been supposed that when crystalline materials are com-minuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led to the author's attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1. The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chem-ical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the cor-rected heat of solution was less for fine material than for coarse. Con-tinuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author's work by

Jan 1, 1936

By Richard Moldenke

So FAR as the quality of the product is concerned, the history of the production of pig iron for foundry purposes is one of constant retrogression. The steps in this deterioration began with cold-blast charcoal pig iron, then anthracite iron, coke iron; then gradually warm to hot-blast coke iron, with the charcoal furnaces also heating their blast to get greater tonnages, and finally the present day hot-blast coke irons with scrap additions to the ordinary burden that, according to one European report, have gone as high as 135 per cent. Parallel with this quality retrogression is the enormous increase in furnace tonnages from about 15 tons daily to over 1000 tons per day in exceptional instances of modern practice. The key to this situation is economic pressure. The effect is a growing differentiation between furnace production for gray iron and malleable foundries and for the production of commercial steel. As the foundry is often compelled to draw upon the pig irons made for steel purposes, for economic reasons, whereas the steel industry does not draw upon foundry pig irons proper, the situation is resolving itself into one of grave consequence for the life of the gray-iron castings industry, and hence the intensive present-day feeling in foundry circles for rigid specifications to govern the quality of pig irons sold for foundry use. In the discussion of a paper on the use of scrap in the blast furnace held recently in the Institute, a very pertinent remark was made by one of the participating furnacemen, who confessed that "the things found wrong by the foundryman with his iron were beyond his depth." It may be added that those things are also beyond the depth of most foundrymen who, however, know from their results that they are getting poorer castings today with many pig irons than they did with those same brands in former years. Under the former fracture buying, the foundryman at least could select the strongest metal, as judged by the sledge, from various brands of similar fracture and pig section, and his results proved the soundness of his conclusions. With the advent of iron analysis, and in spite of the growing uniformity of the metal through greater tonnage

Jan 2, 1927

By Manning W. Cox

Van Stone mine area is situated at the head of Onion Creek on the northwest flank of Gillette Mountain, Stevens County, Washington. The di strict was found during World War I, but the mine did not come into production until 1952. Production to the end of 1965 was 2,242,960 tons of ore that yielded 10,700 tons of lead concentrates and 120,000 tons of zinc concentrates. The area is part of the Selkirk Mountains Zinc-Lead Belt, or Kootenay Arc, extending from near Revelstoke, British Columbia, to Colville, Washington. A thick but incomplete section of Paleozoic marine formations occurs in the Kootenay Arc and is overlain by marine and continental Mesozoic formations. Both are invaded by Late Mesozoic-Tertiary batholiths. The belt is characterized by open complex folding and extensive high-angle and local thrust faulting. Principal ore deposits occur in the highly deformed carbonate rocks of Cambrian age-the Maitlen (Laib) and Metaline formations. The Van Stone mine occurs along a steeply S-shaped fold lying between the Kaniksu Batholith on the west and the Rogers Mountain Fault, a northeast-trending fault on the west flank of the Gillette Mountain Anticline, to the southeast. The fold is cut by northeasttrending faults containing notoriously irregular lamprophyric, diabasic, and pebble dikes. The host rocks, lower Paleozoic dolomites, are decolorized, silicified, and silicated in the mine area. Jasperoid and tremolite are the common alteration minerals. Other gangue minerals are barite, pyrite, brucite, calcite, and, near the batholith, pyrrhotite. Ore minerals are galena, jamesonite, and sphalerite. Ore minerals occur in bunches and pods intergrown with tremolite and jasperoid. Zinc is roughly eight times more abundant than lead. The highest ore outcrops at 3870 feet elevation, and an undeterminable portion has been removed by glacial scour. The lowest drill hole penetration has reached 3220 feet elevation. Oxidation ranges up to several hundred feet in depth and may be most closely related to pre-glacial groundwater circulation. The area of the mine was completely over-ridden by Pleistocene continental glaciers, and the present erosion surface is nearly continuously blanketed by up to 150 feet of glacial outwash.

Jan 1, 1968

By H. Y. Jennings

An extensive field and laboratory experimental program was carried out to compare the waterflood behavior of carefully preserved soft and unconsolidated cores with measurements on the same cores after extraction. Results obtained from using idealized consolidated and unconsolidated porous media in which wettability could be carefully controlled were contrasted with the preserved core data. The controlled tests on idealized porous media investigated the effect of wettability, flood rate, core length, core permeability and consolidation on the displacement of high viscosity oils. It was concluded from these studies that waterfloods are more favorable when carried out with crude oil in preserved soft and unconsolidated cores than with the same cores after they have been extracted and re-saturated. Waterfloods are usually more favorable when carried out with crude oil in extracted .soft and unconsolidated cores than with refined oil of the .same viscosity in the same cores. The less favorable behavior of extracted soft and unconsolidated cores compared to preserved cores is due to alteration of the core by extraction. Preserved cores saturated with native water and oil should be used for laboratory displacement experiments because they more accurately reflect true reservoir behavior INTRODUCTION The demand for low gravity crude oil created by refinery modernization has focused attention on increasing the production of this viscous crude oil. Billions of barrels are in place in fields that are depleted, or nearly depleted, by primary production mechanisms. Since low gravity reservoirs are relatively recent, geologically, the solid matrix material is usually soft and unconsolidated sand. Such formations are also characterized by a high clay content. Evaluation of sophisticated oil recovery processes with the associated high capital investments has increased the demand for special core analysis tests on material from these soft and unconsolidated sand reservoirs. Data in this paper have resulted from an extensive field and laboratory experimental program. The initial objective vras to provide soft and unconsolidated sand cores for laboratory measurements with as little alteration as possible from their reservoir condition. A secondary objective was to compare the waterflood behavior of these carefully preserved cores with measurements on the same cores after they had been extracted and resaturated. When the comparison showed markedly different behavior the final objective was to attempt to explain the difference by making measurements on idealized porous media free of clay in which initial wettability could be carefully controlled. EXPERIMENTS MATERIALS Core Material The preserved cores used in this study were obtained with as little alteration as possible from their reservoir conditions. Special techniques were developed to satisfy this objective. The cores were cut with native crude whenever the crude had the necessary properties to satisfy the minimum drilling fluid requirements. A pure hydrocarbon chromatographic tracer was added to the crude to provide a simple, safe and inexpensive method to distinguish between oil filtrate and formation oil. Details of the tracer technique used in this study and the procedures used to handle and process the soft, unconsolidated cores have been published.' The core samples were then preserved and packaged at the well site with a dip-applied strippable plastic, or by using a rubber sleeve from a rubber-sleeve core barrel. The final step was to insure that the carefully taken and preserved samples were not altered by processing in the laboratory. Some soft and poorly consolidated sands were carefully shaped in the lab and encased in a protective mounting without disturbing their three-dimensional integrity. Many samples were so poorly consolidated that they literally flowed from the package when the seal was broken. A technique was developed to obtain cylindrical plugs from these samples by using liquid nitrogen as the drilling fluid in a conventional core-drill, drill-press assembly. The idealized porous media consisted of sintered rods of Alundum RA 139, outcrop sandstone identified as Al-hambra sandstone and packs of No. 130 Nevada sand. This sand is 95 per cent 140-200 mesh. (Physical properties of these porous media with those representative of preserved cores are in Table 1.) The natural cores and most of the idealized porous media were 1 1/2-in. in diameter and 3-in. long. The samples used to study the effect of core length were 1 1/2-in. in diameter and 12-in. long. Liquids Water and oil produced from the formations being studied were protected from the atmosphere and collected in carefully cleaned glass or plastic-lined containers. The production was free of chemical additives such as emulsion breakers and corrosion inhibitors. The crude oil was

Jan 1, 1967

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period July 10, 1916 to August 1, 1916: W. A. Barnes, San Francisco, Cal. W. J. Mead, Madison, Wis. W. L. Bell, Davenport, Fla. Charles Mentzel, San Pedro, N. M. James P. Clarke, Jr., Little Rock, Ark. H. H. Miller, New York, N. Y. R. A. Carhart, Mitchell, S. D. W. E. Pomeroy, El Paso, Tex. G. M. Colvocoresses, Humboldt, Ariz. M. K. Rodgers, Los Angeles, Cal W. E. Defty, Phoenix, Ariz. S. C. Rodgers, Guanajuato, Mex. Carl F. Dietz, Worcester, Mass. John M. Baker and Hamilton W. Baker have resigned as general manager and mine superintendent respectively of the Baker Mines Co., of Oregon. After Aug. 1, their address will be 43 Emerson St., Denver, Colo.

Jan 9, 1916

K. W. Turner, Sail Francisco, Cal. (communication to the Secretary*): The recent papers in the Transactions by Vogt,' Lindgren2 and Weed: on ore-deposits that have formed as a direct result of igneous intrusions, show that deposits of this class are widely distributed over the world, and are occasionally of commercial value. This is especially true if we consider under this head all deposits in the zone of contactrnletamorphism, the origin of which may be ascribed to the gases and vapors generated by the heat of the intrusive rock. Mr. Smith's description of the Chillagoe garnet-formations containing copper, leads one to regard these depoaits as of contactrmetamorphic origin, although he gives certain reaeons for supposing them to be of igneous origin.

Jan 1, 1904

By H. A. J. Wilkens, H. B. C. Nitze

From time to time papers treating of specific cases of Southern gold-mines and mining have appeared in the Transactions of this Institute, as well as in other journals and publications. Mr. George I?. Becker, of the United States Geological Survey, made a reconnaissance of the Southern Appalachian gold-belt during the fall of 1894; the results of his investigations are published under the title of "A Reconnoissance of the GoldFields of the Southern Appalachians," in the Sixteenth Annual Report of the Director of the United States Geological Survey, 1894-95 : Part III., " Mineral Resources of the United States." Mr. Becker has treated the subject mainly in a scientific geological manner. We present this paper to the members of the Institute as requested by the Secretary last May, with the object of covering the ground from a more practical and technical standpoint. The notes for this paper were made in a large measure from personal observations, gained chiefly during the past summer on a trip through the field. In connection with this trip we collected a suite of typical hand-specimens, representing the gold-ores and wall-rock from the more important localities. This collection forms a part of the exhibit

Jan 1, 1896

By R. H. Tien

Temperature distribution as well as position of the solidified front is solved by means of "heat balance integral", for the case of freezing a slab with time-dependent surface temperature. Numerical solutions for the cases of linear variation and exponential decay for surface temperature are given. Application also includes solidification of casting. An increased interest in the heat-transfer problem involving a change of phase has been developed in recent years. Practical problems include solidification of a casting, freezing and thawing of soil, ice formation, and others. Despite the importance of the topic, a literature search reveals relatively few solutions which may be extended to practical problems. Due to mathematical complexity, which comes from the nonlinearity of governing differential equations, exact analytical solutions which have been published are limited to a few cases with simple boundary conditions. Although numerical solutions of these problems have become available after highspeed digital computers were introduced, lack of simple and general methods of programming for computation makes this approach impractical. The case of the semi-infinite slab with constant surface temperature was solved in the 19th century. In honor of Neumann, who first found an analytical solution, this kind of problem is generally referred to as the Neumann solution. As has been shown in Fig. 1, the problem to be analyzed is the freezing of a semi-infinite region (x > 0) which is initially liquid at the melting temperature with the surface (x = 0) maintained at time-dependent temperature. This analysis can be applied to the study of many casting processes where most of the heat removal is essentially unidirectional. "Heat balance integral" which has been used by Goodman1 is employed in this analysis. The concept of "heat balance integral" is to define a quantity, d(t), called the thermal layer. Beyond this thermal layer, for all practical purposes, there is no heat transfer, and the region is at the equilibrium temperature. "Heat balance integral" is obtained by integrating the conduction equation with respect to the space variable over this thermal layer d(t). Choosing some plausible temperature distribution, usually a polynomial or a finite trigonometric series in the space variable, this integral equation becomes an ordinary differential equation, with time as the independent variable, which can be solved by classical methods. The thermal layer and "heat balance integral" are equivalent, respectively, to the boundary-layer thickness and the momentum integral in hydrodynamics. A modern account of Prandtl's concept of the boundary layer and von Karman's momentum integral may be found in Ref. 2. Although the problem considered here has been limited initially to uniform melting temperature, the present method is equally applicable to the case with arbitrary temperature distribution in the liquid. STATEMENT OF THE PROBLEM The physical situation and coordinate system used in the problem to be analyzed are shown in Fig. 1. Notations used are listed in the table of nomenclature. Let us assume a semi-infinite region extending over positive x, initially at the uniform melting temperature. At the surface x = 0, a time-dependent temperature, which has a numerical value

Jan 1, 1965

By N. A. Gokcen, J. Chipman

A revised treatment of the authors' published data eliminates the complex relation previously proposed between concentration of silicon and activity coefficient of oxygen in liquid iron. Revised values of the thermodynamic properties of the liquid solution are presented. IN a recent experimental study of the reaction SiO2 (s) = Si+ 2O; Kf, = [% Si] [% O]² [1] the authors' found a substantially constant equilibrium product in liquid iron at 1600°C of 2.8x10-5 They also reported extensive data on the reactions: SiO2 (s) + 2H2 (8) = Si- + 2H2O (g); K'2= [% Si] (H2O/H2 [2] and H, (g) + 0 = H2O (g); K'3 =( H2 O [31 (H2) [%O] From the results on reaction 3 and earlier data of Dastur² on this same reaction in the absence of silicon, they determined the activity coefficient of oxygen, f0, on the basis of the definition K3 = (H2O)/ (H2)f0 [% 0] where K, is the equilibrium constant and f0, is taken as unity in the pure Fe-0 system. Similarly values of fsi were deduced from results on reaction 2. In a more recent study" of analogous reactions in the system Fe-A1-0, it was found impossible to reconcile the results on reaction 3 with Dastur's data; accordingly the latter were ignored and the equilibrium results were extrapolated to find a value of K, at zero concentration of aluminum. This procedure failed to locate the cause of the discrepancy but it did yield reasonable values of activity coefficients. It also avoided introduction of the complex empirical relation between the oxygen activity coefficient and the concentration of the added element. The same type of discrepancy exists for system Fe-Si-0.' In the earlier paper an attempt was made to fit both sets of data by a single curved line (Fig. 6 of ref. l), the form of which is contrary to the theoretical requirement of a finite slope at infinite dilution. In the light of experience on the Fe-A1-0 system the discrepancy must be recognized as one which can be resolved only by more refined measurements. Accordingly Figs. 6 and 10 are retracted. It is pointed out also that until the discrepancy is resolved Figs. 7, 8, and 11 are subject to some uncertainty. Qualitatively the following conclusions still appear valid: 1—The activity coefficient of oxygen is reduced by addition of silicon. 2—In dilute solutions the activity coefficient of silicon increases with its concentration. 3—With respect to equilibrium in reaction 1, the above effects are approximately compensating. The discussion of K'1 in the previous paper requires no revision. It was pointed out that the constancy of the product [% Si] [% 0]² ndicated a compensating effect of the activity coefficients of silicon and oxygen. Therefore, as a very good approximation, K1 = K'1 and the following average values are suggested both for K, and K', at the temperatures 1550°, 1600°, and 1650", respectively, 1.0x10-", 2.8~10-" and 5.5 ~lo-'. Revision of the thermodynamic treatment is necessitated by the recent appearance of new data, based on a combination of combustion and solution calorimetry,' which yields for the heat of formation of low-cristobalite from the elements, the value —209,330 ±250 cal per mol at 25°C. This is about 4000 cal larger than the value previously accepted. The new value for cristobalite is used, together with Kelley's tables of high-temperature heat contents" and entropies and with Korber and Oelsen's' heat of fusion of silicon to obtain the following equation for the standard free energy of cristobalite in the temperature range 1700" to 2000°K: Si (1) + 02 (g) = Si02 (crist.); ?F° = -217,700 + 47.OT [4] The free energy of solution of 0, in liquid iron is:8 O2 (g) = 20 (in Fe); AF° = -55,860 - 1.14T [5] and these two equations are combined to give: Si (1) + 20 = SiO, (crist.); AF° = -161,840 + 48.14T [6] ?F°1873 = -71,700 cal. From the experimental value of K, = 2.8x10-5, Si + 20 = SiO2 (crist.); ?F°1873 = -39,000 cal. [7] The combination of Eqs. 6 and 7 yields the free energy change when liquid silicon dissolves in iron to form the dilute solution of unit activity (1 pct). Si (1) = Si; ?F°1873 = -32,700 cal. [8] The heat effect in this process according to Korber and Oelsen' is an evolution of 28,500 cal per gram

Jan 1, 1954

By R. A. Meussner, C. T. Fujii

Chromium solution in wustite depresses the oxygen activity in a nonideal manner and expands the lattice slightly. Gravimetric measurements of the equilibrium compositions of wustite containing 0.00 to 1.38 wt pct Cr define the oxygen potential (CO2-CO atm) and the limits of the phase field at 1000°C. These data extrapolate to a maximum solubility of 2 wt pct Cr. The lattice parameter data, room-temperature measurements of quenched samples, differ significantly from those in the literature. Both pure and chromium wus-tites contract at uniform and equal rates as the oxygen content (metal deficit) increases. The a. US metal deficit relationships are straight lines showing none of the curvature previously reported. At constant metal deficit, the a. expands by 0.002? on alloying with 0.4 to 0.5 wt pct Cr but is insensitive to further chromium additions: a small expansion rather than a marked contraction. These results require a modification of the accepted alloying mechanism. IN the high-temperature oxidation of Fe-Cr alloys in Ha-H,and CO2-CO atmospheres the vapor transfer of oxygen from the continuous wustite outer scale to the porous inner scale/alloy interface sustains the high oxidation rates.1"3 The driving force for this transport is the difference in the oxygen activity of the outer wustite and that at the inner scale/alloy interface. In pure CO2, as well as in CO2-CO atmospheres, carburization of the alloy accompanies this oxidation. Current efforts to evaluate the parameters controlling this carburization have shown that the process is not simple; i.e., the carbon concentration in the alloy initially increases rapidly, reaches a maximum, and then decreases slowly as the oxidation time is extended. This is the same pattern reported by McCoy for the more complex oxidation-carburization of stainless steels and an Fe-Cr alloy in CO2 at lower temperatures.4 These changes in the carburization process occur while the overall oxidation rate and the lattice parameters of the scale layers remain constant. If this invariance of the lattice parameter is assumed to indicate a constant scale composition and thus a constant oxygen potential, the carburization results are not easily explained. Electron microprobe traces across the thickness of these outer scales, however, have revealed distinct chromium gradients penetrating 10 to 50 µ from the inner surface where the chromium concentrations were estimated at a few tenths percent. The variation of the chromium cmcentration on the inner surface of the scale, and the resulting change of the oxygen activity, during the oxidation process is considered to be important in defining the carburization process. Thus, to gain an understanding of the complex oxidation-carburization proc- ess, it was necessary to measure the properties of wustite containing known amounts of chromium (chromium wustite). Although the general features of the Fe-Cr-0 equilibrium diagram between 900° and 1300°C have been fairly well established by Richards and white: Wood-house and White,6 Seybolt,7 and Katsura and Muan,8 there have been no detailed studies of the limits of the chromium wustite phase field or the properties of these alloyed wustites. The recent results of a limited study of chromium wustite by Levin and wagner9 indicate that more than 0.67 wt pct Cr is soluble in wustite above 850°C and that this alloying is accompanied by a substantial lattice contraction. This change in the lattice parameter was not evident in the X-ray diffraction patterns of wustite layers from the oxidation experiments;1,3 the lines were sharp even though a chromium gradient existed in the scale. The present paper describes gravimetric equilibrium experiments which delineate the boundaries of the chromium wustite single-phase field at 1000°C and define the changes in the oxygen activity and the lattice parameter of wustite as functions of chromium and oxygen contents. The lattice parameter data of chromium wustite obtained from these equilibrium and special quenching experiments differ considerably from those reported.9 Those for pure wustite show significant differences from the widely accepted data of Jette and Foote.10 Since the causes of these differences are not easily assignable, and since the literature contains many sets of data on wustite which if not in conflict are at best not in harmony, the experimental procedures are discussed in the present paper. EXPERIMENTAL Oxide Preparation. The specimens used in these studies were porous pellets compacted from high-purity (Fe,Cr)2O3 or Fe2O3 powders. These powders were prepared from electrolytic chromium (99.8 pct purity) and electrolytic iron purified by consumable-electrode, vacuum arc-melting processing (299.9 pct purity).11 The oxides were produced by standard analytical procedures: solution of the metals in acids (HC1, then HNO3 added), coprecipitation of the hydroxides (NHaOH), and filtering and washing these precipitates. Initial dehydration of the coprecipitated hydroxides was done in a porcelain evaporating dish heated by a Meker-type burner, final dehydration by firing in a recrystallized alumina crucible at 1000" to 1050°C for 20 hr in an electrically heated furnace. Spectrographic analysis detected the following impurities: silicon, 0.01 pct or less; aluminum, 0.001 pct to trace; manganese and copper, 0.0001 pct to none. Each of these levels is at least one order of magnitude lower than in commercially available CP grade ferric and chromic oxides. Fluorescence analy-

Jan 1, 1969

By M. J. Sinnot, J. C. Shyne

Low-frequency mechanical damping measurements were made to investigate internal friction in Fe-A1 alloys. The atomic ordering of the Fe-A1 system strongly influenced the stress-induced ordering internal friction. Magnetoelastic damping was also encounteyed and was shown to be reduced by the application of a static stress. THIS paper describes some damping experiments made on alloys of Fe and Al. Stress-induced ordering internal friction was measured with samples containing from 9.8 to 31.3 at. pct Al. Aluminum is soluble in a-Fe to about 50 at. pct and forms at least two long-range ordered structures, Fe3Al and Feu.' Stress-induced ordering internal friction is known to occur in many substitutional solid solutions, but few measurements of this damping effect have been made with alloy systems that have pronounced ordering tendencies. LeClair and Lomer developed expressions relating the relaxation strength of the damping process to the degree of atomic ordering and predicted that stress-induced ordering internal friction would be zero with complete ordering.' This concept was confirmed experimentally by Lulay and Wert using the system cd-Mg It is also consistent with the weak stress-induced ordering peaks observed in P -brass by Artman and in 16 wt pct Al Fe-Al by bert.' It was expected, therefore that the ordering characteristics of the system Fe-Al would strongly influence the stress-induced ordering internal friction exhibited by the experimental alloys. SAMPLE PREPARATION The alloys used in this investigation were induction melted under vacuum using high-purity melting stock. The iron was electrolytically refined Plastiron 101 which contained 99.85 wt pct Fe. The aluminum was a special 99.95 pct pure grade supplied by Alcoa. The only other raw material was spectrographically pure graphite which was used in small quantities as a deoxidant. The amount of carbon used was slightly in excess of the amount required to completely deoxidize the melt; this resulted in residual carbon contents of 0.01 to 0.02 pct in the finished alloys. The vacuum cast 2 1/2-in. diam ingots were hot rolled to 5/8-in. diam round bars. Portions of these bars were hot swaged and hot drawn to 0.050-in. diam wire. Straight pieces of the hot drawn wire were slowly heated to a temperature of 1300°C in a He atmosphere. After holding for 4 hr, the samples were allowed to cool in the furnace. This annealing treatment resulted in grain growth in the samples, the final grain size being about the same as the wire diameter. The grain boundaries were oriented perpendicularly to the wire axis, giving a bamboo grain structure. The existence of a preferred orientation could not be detected in these coarse grained samples. If the samples had a fiber structure, this probably would have been the same in all samples because of similar processing, thus the influence of crystal orientation on the relaxation strength would have been similar in all samples. The aluminum contents of the alloys are listed in Table I. EQUIPMENT The principle of the torsion pendulum was used for the internal friction measuring device. The

Jan 1, 1961

By J. J. Brown

Wilkes-Barre Meeting, Julie, runs., THE ore-hearth was the earliest type of furnace used in smelting Mississippi Valley lead-ores, which are very pure, and low in silver-content. The first smelters made no attempts to recover lead from the smoke; and since about 15 per cent. of the lead -in the charge escaped in this manner, early practice with the hearth was decidedly wasteful. At most of the large smelting-plants blast-furnaces with auxiliary roasters were substituted for the hearths long ago. But, upon the introduction of the Lewis and Bartlett bag-process for collecting fume, the ore-hearth was used by companies engaged in the manufacture -of pigments, simply on account of the large percentage of fume made by it. In fact, the extraction of lead was kept down by the use of hot blast and other devices. During recent years, however, several smelting companies have realized that the preliminary roasting of galena for the blast-furnace is not economical, and have, therefore, replaced the roasting-furnace with a modification. of the old Scotch hearth, in which a large percentage of the lead in a charge is recovered directly as pig-lead, while the remainder passes partly into fume and partly into slag low enough in sulphur to be charged into the blast-furnace without further treatment. The results obtained have proved so satisfactory, both As to recovery and operating-expense, that one eminent metallurgist has predicted the universal use of the ore-hearth on non-argentiferous ores. The-ore-hearth, thus employed as an adjunct to a blast-furnace plant, is rather a desulphurizer than a smelting-furnace proper,-the chief object being to make a blue slag suitable for the cupola-furnace. Hence, no special care is taken to obtain from it a large lead-extraction. * Head of Department of Ore Dressing and Metallurgy, Oklahoma School of Mines and Metallurgy, Wilburton, Okla.

May 1, 1911

By Richard Moldenke

So far as the quality of the product is concerned, the history of the production of pig iron for foundry purposes is one of constant retrogression. The steps in this deterioration began with cold-blast charcoal pig iron, then anthracite iron, coke iron; then gradually warm to hot-blast coke iron, with the charcoal furnaces also heating their blast to get greater tonnages, and finally the present-day hot-blast coke irons with scrap additions to the ordinary burden that, according to one European report, have gone as high as 65 per cent. Parallel with this quality retrogression is the enormous increase in furnace tonnages from about 15 to over 1000 tons per day in excep tional instances of modern practice. The key to this situation is economic pressure. The effect is a growing differentiation between furnace production for gray iron and malleable foundries and for the production of commercial steel. As the foundry is often compelled to draw upon the pig irons made for steel purposes, for economic reasons, whereas the steel industry does not draw upon foundry pig irons proper, the situation is resolving itself into one of grave consequence for the life of the gray-iron castings industry, and hence the intensive present-day feeling in foundry circles for rigid specifications to govern the quality of pig irons sold for foundry use. In the discussion of a paper on the use of scrap in the blast furnace held recently in the Institute, a very pertinent remark was made by one of the participating furnacemen, who confessed that "the things found wrong by the foundryman with his iron were beyond his depth." It may be added that those things are also beyond the depth of most foundrymen who, however, know from their results that they are getting poorer castings today with many pig irons than they did with those same brands in former years. Under the former fracture buying, the foundryman at least could select the strongest metal, as judged by the sledge, from various brands of similar fracture and pig section, and his results proved

Jan 1, 1927

By V. N. Mackiw

IN the process employed by Sherritt Gordon Mines Ltd. for the production of metallic nickel, a sul-fide concentrate is leached with ammonia and air under pressure. Following the removal of iron, copper, and other impurities, there remains a purified solution having the following analysis: 40 to 50 g per liter Ni, 200 to 400 g per liter (NH4)2 SO 4, and 20 to 30 g per liter NH3. Metallic nickel is reduced from this solution by hydrogen under pressure at 300' to 350°F in mechanically agitated autoclaves. A catalyst, ferrous sulfate, is required to initiate the first reduction. After the reduction, the depleted solution is discharged, leaving the metallic nickel in the autoclave. The nickel produced, being in a finely divided form, is used as a catalyst for the reduction of the next batch of solution. Upon repeated use the metallic nickel particles increase in size and become more compact, resulting in the production of a powder with higher apparent density. For this reason, each reduction is termed densification. Finally, when the burden of metal powder in the autoclave becomes too great to obtain effective agitation, both powder and depleted solution are discharged. The autoclave is then filled with fresh solution, ferrous sulfate catalyst added as before, and a new cycle started. The operation is described in earlier publications.1-6 A comprehensive historical review of the reduction of metals from solutions in general was given in a paper by Schaufelberger.7 The experimental data presented in this paper were taken from the work done in the Research Laboratory of Sherritt Gordon Mines Ltd. in Ottawa during the development of the process in 1951 and 1952. The results of the work were tested on a pilot plant scale in Ottawa in the period 1952 to 1953. Following laboratory and the pilot plant studies a commercial process has operated successfully since 1954 in the Nickel Refinery of Sherritt Gordon Mines Ltd. in Fort Saskatchewan, Alberta. General Experimental Technique The experiments were carried out in a stainless steel, 1-gallon, agitated autoclave designed and manufactured by Autoclave Engineers Inc. The inside dimensions of the vessel were 5 in. diam and 12 in. depth. The stirrer consisted of a 1/2 in. diam shaft 11 in. long fitted, with an axial flow type impeller (three blades bent to throw downwards) and a radial flow

Jan 1, 1958

By Robert F. Mehl

THIS essay is an attempt to present the elementary facts and ideas concerning the growth of crystals, especially of metals. Freezing, like all heterogeneous processes, is a process of nucleation and growth; it manifests itself in metallurgy primarily in the freezing of ingots. The preceding paper in this volume discusses nucleation; the paper to follow describes ingot solidification. The present paper will treat of the growth of nuclei to large crystals, embracing a long series of phenomena, many of which are familiar to metallurgists.† Crystal growth, it will be immediately noted, occurs not only in the freezing of metals, but in the freezing of all substances; and it is a prominent and familiar phenomenon in crystallization from solutions, aqueous or otherwise, and in crystallization from the vapor phase. It will be necessary to include such systems in this discussion, for so much of value to metallurgists has been learned from their study. Apart from this, so far as metals are concerned, it will be simpler to limit the discussion to the freezing of pure metals and of solid solutions. Other types of freezing-eutectic, peritectic, etc.-will be excluded, though they have much of interest and of importance. BASIC MECHANISM OF FREEZING Ideally, nucleation and growth processes can best be considered from the point of view of isothermal reaction and upon the assumption of random nucleation. In. such an ideal case, nuclei form at random, and at a characteristic rate either constant or changing with time, and grow to spherulites at a characteristic rate, constant or changing with time, Fig. I.. On the simplest assumption, the reaction rate-in this case the rate of freezing-is a resultant of these two component rates. The reaction rate equation may be written in terms of these two component rates. The formation of pearlite from austenite closely approaches this ideal case. The ideal case forms a very useful point of departure in considering real cases. Various factors of reality produce deviations from this assumed ideality. In freezing, the isotropic medium, the melt, passes to the anisotropic solid, the crystal. Crystals are lattices of atoms, and the unit cell is often referred to as a crystal unit. Rosenhain, many years ago, represented the nucleation and growth process on freezing in the manner shown in Fig. 2, feeling, intuitively, that there must be some crystal unit in crystal growth. It now appears that this may be true, though his picture requires much elaboration. The greatest deviation from ideality lies in the nonisothermal nature of the freezing process in metals. To approach this properly it should be recalled that many nonmetallic substances freeze slowly. Tammann, to whom we owe the classic approach, studied complex organic materials in which (as in the case of eutectoid steels at high

Jan 1, 1951

By Paul Pietrokowsky

THE formation of intermediate phases in the solid state reaction of titanium with silicon, germanium. and tin (of subgroup 4B in the periodic table) was the subject of a recent paper.' Further investigation of the system Ti-Sn revealed the presence of a new compound on the titanium-rich side of this phase diagram. Metallographic evidence indicated that this new phase was situated very close to 75 atomic pct Ti. The present work is concerned with the crystal structure of the intermediate phase Ti3Sn. Iodide-process titanium metal, furnished by the New Jersey Zinc Co., was used in this investigation. The metallic tin was received in powder form from Charles Hardy Inc., New York; its purity was 99.80 pct. The titanium rod was machined into small cups 1 cm in diam and about 1.5 cm in height. The tin powder was compacted, melted, and then placed in the titanium cups and alloyed by electric arc melting in a helium atmosphere. The alloys, weighing approximately 8 g, were sealed in evacuated quartz tubes and homogenized at 1030°C for 5 days. This isothermal heat treatment was terminated by a water quench from the soaking temperature. Filings of the alloyed pellets were sealed in evacuated quartz bulbs and quenched from 1030°C into liquid argon. A 14.32 cm Debye Scherrer X-ray camera was used for the powder diffraction study. The copper radiation was filtered. X-ray diffraction data for the compound Ti3Sn are given in Table I. The data were indexed on the basis of a hexagonal lattice. Good agreement between observed and calculated values of the square of the reciprocal interplanar spacings was obtained with the following expression: (1/d)2 = 0.03810 (h2 + hk + k2) + 0.04410 (l2) Unit cell parameters were calculated by the method of least squares from the reflections (20.3), (22.2), (40.1), and (42.1); ao = 5.916 & 0.004A, co = 4.764 ± 0.004A, and co/ao = 0.805. The relatively small size of the unit cell allowed the unambiguous indexing of most of the reflections from planes of large spacing. An inspection of the assigned indices (Table I) reveals the absence of (hk.l) reflections when 1 2n. A systematic absence of this type leads to the space group C 6/mmc or one of its subgroups. Assuming, for a first approximation, a linear increase in the density of titanium with the addition of tin, it follows that there are two stoichiometric molecules of Ti3Sn per unit cell. The density calculated from X-ray measurements is 5.194 g cm-'. At this point it became clear that Ti3Sn might be isomorphous with Mg3Cd. The 6 Ti and 2 Sn atoms were placed in the following positions of space group D4 6h, C 6/mmc: 6Tiin (h): X 2X 1/4; 22;; 1/4;Xx 1/4;x2x3/4; 2x x 3/4; x x 4; with x = 516 2 Sn in (c): 1/3 2/3 1/4; 2/3 1/3 3/4.

Jan 1, 1953

"Mining as an industry of Utah had its inception in the activities of United States soldiers who came to the Salt Lake valley under the command of Gen. P. E. Connor, founder of Fort Douglas, in October, 1862. Many of these soldiers were from California and naturally employed their spare time in the search for minerals. Although their military status did not permit them to make locations in their own names, they assiduously prospected the region in accordance with their own knowledge and with information conveyed to them by Indians and others. Their efforts were encouraged by their commander, who thereby fairly earned the title of father of the industry here, and by their other officers, and many discoveries that subsequently proved of great value were made by the soldiers.No systematic prospecting or mining had been done in the Territory previously, although early Mormon settlers in the southern portion had mined a little ore from time to time in order to provide supplies of lead for bullets. The Mormon leaders at that time did not encourage mining. They held that agriculture was more important and profitable for their followers.Coal was discovered and produced in 1850. Iron was discovered in 1850 and the first iron plant was in operation in 1852 in Iron County. The first non-ferrous metal production was in 1854, in Beaver County, when Isaac Grundy treated ore from the Rollins mine in what is said to have been the first lead furnace west of the Rocky Mountains. The first mineral location was the West Jordan claim in Bingham canyon, located September 17, 1863, now owned by the United States Smelting, Refining & Mining Co., and still productive. The first district organized in the state was the West Mountain (Bingham), December I 7, 1863. Other important districts of early organization are: Little Cottonwood, December 20, 1869; Big Cottonwood, July 11, 1870; American Fork, July 21, 1870; Uintah (Park City), July 8, 1871; Tintic, December 13, 1896; Ophir, August 6, 1870. The first silver-lead smelting was by J. W. Gibson at Stockton in 1866. Lieut. James Finnerty had previously erected two small trial furnaces there, but made no quantity production."

Jan 1, 1925