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The growth and influence of Sherritt Gordon Mines Ltd. in the nickel producing industry has been quite phenomenal. Although the company's Lynn Lake deposit in Manitoba was actually dis- covered in 1941, it was not until 1945, when men and materials were more readily available as a result of the end of World War II, that the area was staked and news of the discovery leaked out. As a result of the discovery, Professor Frank Forward of the University of British Columbia was commissioned by Eldon Brown, then President and Man- aging Director of Sherritt, to develop a new nickel refining process. A pilot plant, based on the results of Professor Forward's research, was constructed in Ottawa, and after the successful testing of the Lynn Lake ore, Chemical Construction Co. was given a con- tract in 1952 for construction of a producing plant. By 1954, the Fort Saskatchewan refinery was operating at an annual production of 15 million lb of nickel metal in the form of briquetts or powder. Capacity has since been increased to 30 million lb.

Jan 10, 1968

By R. Kossowsky

Structural changes in Be-Cu, Be-Ni. Be - Ag, and Be-Fc alloys pressurized in a solid medium were invesligated by resistivity measurements , X-ray diffrac lion in situ and metallogvaphic examination. Some limited tests in liquid medium were also conducted. Good correlation was oblained between diauges of slope of relative resistance us pressure and changes in diffraction pattern. Metallographic examination rez:ealed that the copper, silver, and nickel alloys lwiu heauily due to the applicalion of pressure at room temperature. Using polarized light technique {1012}, {1011}, and possible {1010} twinning planes were identified. At eleuated temperature twinning was moslly confined to the {1012} planes. Although twin-ning could be promoted by application of hydroslutic pvessure (liquid medium), it was strongly enhanced by the pvesence of a nonhydvostatic shear component due to pressurizalion in a solid medium. It was further obserced that a decrease in grain size inlnibiled twinnitzg activily. A great deal of effort has been expended in recent years to render beryllium useful for structural applications. Efforts were concentrated towards a possible phase change and to promoting other than basal deformation modes. Quenching experiments to obtain the high-temperature bcc phase have failed,' nor were alloying additions successful in improving ductility of the brittle hcp phase.2 Herman et a1.3 have reported a new {1011} twinning mode in a Be-4.4 wt pct Cu alloy oriented for a C axis compression sustaining loads to 440,000 psi. A new approach using high-pressure techniques was undertaken at Curtiss-Wright, Wright Aeronautical Division Laboratories. Marder4 reported a 25 pct decrease in relative resistance of commercially pure beryllium at 92 kbar. He proposed that this discontinuity corresponded to the bcc phase found at high temperature; however, X-ray diffraction in silu did not confirm a phase transition.5 contre6 has recently shown that the bcc transition in pure beryllium is lowered to 800°C at 80 kbar accompanied by a 50 pct increase in relative resistance. The purpose of this paper is to report on one phase of an investigation of the effects of high pressures and temperatures in beryllium alloys, namely, twinning behavior in Be-Ni, Be-Cu, Be-Fe, and Be-Ag alloys pressurized to nearly 100 kbar and temperatures up to 200°C. EXPERIMENTAL METHODS Material was obtained from Nuclear Metals, Inc., in the form of a 1.5-mm-diam wire extruded in stainless-steel cladding at 1600° F. Nominal composition of the alloys is listed in Table I, and the major impurities are are given in Table 11. Pressures to 100 kbar* were ob- tained using a National Bureau of Standards type 100/400 ton tetrahedral unit supplied by Barogenics, Inc. This type of apparatus contains a retaining sleeve with a conically tapered internal surface and four pressure-intensifying anvil assemblies with tungsten carbide tips. The 10-mm-long specimen fits into a pyro-

Jan 1, 1968

By J. R. Craig, T. N. Solberg, M. A. Linden

The central and southern Appalachian Mountains were the major sources of domestically produced gold throughout the first half of the 19th century and continue to yield gold today. Small amounts of gold were probably extracted by the Indians and the Spaniards but the first documented report of gold in the region was made by Thomas Jefferson who found, in the Rappahannock River of Virginia in 1782, a 1.8 kg (4 lb) lump of gold ore that yielded 26 g (0.85 oz). Gold was subsequently discovered in North Carolina between 1793 and 1799, in Virginia in 1806, in South Carolina in 1827, in Georgia in 1829, and in Alabama about 1830 (Becker, 1894-5; Pardee and Park, 1948). Production climbed to more than 933 kg/a (30,000 oz per year) between 1830 and 1852, but dropped sharply after the California gold rush in 1849 as experienced miners moved west in search of bigger and easier stakes. The Civil War briefly halted gold mining in the Appalachians, but production rose to an average of about 249 kg/a (8,000 oz per year) from 1865 until 1878 and to about 404 kg/a (13,000 oz per year) from 1881 until 1915 when it again fell to near nil (Pardee and Park, 1948). Minor resurgences occurred in the 1930s and 1940s. Although there has been no reported production in recent years, it is likely that "weekend panners" still remove hundreds of ounces from streams annually. The total reported production for the area through 1959 is more than 77 t (2.5 million oz). This paper reports some initial findings of a long-term project designed to investigate the mineralogy, chemistry, mode of occurrence, and petrology of gold occurrences in the Appalachians. The goal of the initial phase was to determine the compositional range of gold in the Appalachians as a step toward deciding if sufficient variations were present to allow the definition of "compositional signatures." The very few published data on gold fineness in the Appalachians are based on assays that commonly include gold and silver from several mineral species. Analyses in the present study were performed on individual grains of electrum using a spot size of 10 µm x 10 µm to 100 µm X 100 µm (394 X 394 micro in. to 3,940 X 3,940 micro in.), and thus reveal the true composition of the principal precious metal-bearing phase.

Jan 1, 1984

By Michael B. Bever, John R. Anderson

Carbon may affect the alloys of copper in several ways. Provided an alloying element does not oxidize preferentially, even minute quantities of carbon dissolved in liquid alloys of high copper content will form insoluble carbon oxide gases under oxidizing conditions. Gas porosity in castings of high-copper alloys can originate in this way. In certain alloys of low copper content carbon may have considerable solubility and may be an effective deoxidizer. In these alloys carbon will tend to suppress porosity. Carbon that is dissolved in the molten alloy is likely to be retained in the solidified metal. The effects of carbon on the physical properties of the metal are determined by the form in which it is present. Depending on the alloying elements and also on the cooling rate, carbon may precipitate as graphite, may form a carbide or may remain in solid solution on cooling. As solid copper does not dissolve a measurable amount of carbon, a carbon-bearing solid solution can occur only if the copper is alloyed with a large excess of an element that forms such a solution. The effect of graphite or of carbides on the properties of an alloy will depend on the size and distribution of the precipitated particles. As Hensel pointed out in discussion,' the formation of an alloy carbide may interfere with the age-hardening properties of a copper alloy. One would also expect that the presence of carbides or of graphite will under certain conditions promote corrosion or high-temperature failure in nonferrous alloys. Since carbon has an effect on the soundness of castings and affects the structure and behavior of solid copper alloys, its solubility in the liquid alloys is of practical importance. The isothermal change of carbon solubility with alloy composition is of interest from a theoretical standpoint. The binary alloys of copper with manganese and with nickel are used industrially and serve as a base for more complex alloys. The solubility of carbon in each of these metals is known, but its solubility in their alloys has not been determined. Earlier Data The solubility of carbon in molten pure copper is about o.oooi pct at II00°C and 0.0004 pct at 1475°C.l Various authors2""6 have published data on the solubility of carbon in molten manganese. There is agreement on a value of about 6.7 pct in the temperature range r2170 to 1245°c This solubility value corresponds to the formula Mn3C. It increases very little with increasing temperature. Corson7 states that carbon is soluble in copper-manganese alloys and that the

Jan 1, 1947

By John R. Anderson, Michael B. Bever

Carbon may affect the alloys of copper in several ways. Provided an alloying element does not oxidize preferentially, even minute quantities of carbon dissolved in liquid alloys of high copper content will form insoluble carbon oxide gases under oxidizing conditions. Gas porosity in castings of high-copper alloys can originate in this way. In certain alloys of low copper content carbon may have considerable solubility and may be an effective deoxidizer. In these alloys carbon will tend to suppress porosity. Carbon that is dissolved in the molten alloy is likely to be retained in the solidified metal. The effects of carbon on the physical properties of the metal are determined by the form in which it is present. Depending on the alloying elements and also on the cooling rate, carbon may precipitate as graphite, may form a carbide or may remain in solid solution on cooling. As solid copper does not dissolve a measurable amount of carbon, a carbon-bearing solid solution can occur only if the copper is alloyed with a large excess of an element that forms such a solution. The effect of graphite or of carbides on the properties of an alloy will depend on the size and distribution of the precipitated particles. As Hensel pointed out in discussion,' the formation of an alloy carbide may interfere with the age-hardening properties of a copper alloy. One would also expect that the presence of carbides or of graphite will under certain conditions promote corrosion or high-temperature failure in nonferrous alloys. Since carbon has an effect on the soundness of castings and affects the structure and behavior of solid copper alloys, its solubility in the liquid alloys is of practical importance. The isothermal change of carbon solubility with alloy composition is of interest from a theoretical standpoint. The binary alloys of copper with manganese and with nickel are used industrially and serve as a base for more complex alloys. The solubility of carbon in each of these metals is known, but its solubility in their alloys has not been determined. Earlier Data The solubility of carbon in molten pure copper is about o.oooi pct at II00°C and 0.0004 pct at 1475°C.l Various authors2""6 have published data on the solubility of carbon in molten manganese. There is agreement on a value of about 6.7 pct in the temperature range r2170 to 1245°c This solubility value corresponds to the formula Mn3C. It increases very little with increasing temperature. Corson7 states that carbon is soluble in copper-manganese alloys and that the

Jan 1, 1947

By J. Rogers, K. L. Sutherland

THE relationships between collector and mineral, activator and mineral, and activator, collector and mineral will be considered herein. We propose to criticize current theories of flotation but we will not repeat the many pertinent arguments presented by Wark and Cox28 in 1937 in which the "chemical" or more strictly the "solubility" theory proposed by Taggart and co-workers22 is shown to be untenable. Recently Taggart, Arbiter and Kellogg24 have studied the long-chain aliphatic amines as collectors and have attempted to resuscitate the solubility theory for these particular collectors. Dean and Ambrose3 have felt that "we stumble over words" when we distinguish different mechanisms of adsorption. Our view is that nothing is more stultifying to the development of a science than attempts to force widely different phenomena into one classification. This oversimplification leads immediately to difficulties in the interpretation of results. EXPERIMENTAL PROCEDURE The response of minerals to activator and collector was determined by "captive-bubble" tests. The methods of preparation of specimens26 and of testing18 have been previously described. Results from captive-bubble tests were confirmed by flotation tests in glass-stoppered cylinders.25 The full lines shown in the figures relating solution composition to contact (flotation) distinguish solutions in which contact (flotation) is possible from those in which it is not. The curve is derived by successive approximation and the accuracy is ±0.2 pH units and ± 5 mg. per liter of collector or depressant. Solution compositions for which it was shown experimentally that contact or flotation is possible are marked by a circle, those for which it is not possible by a cross and those for which it is doubtful by a cross within a circle. It is assumed that at all other solution compositions within (without) the curve, contact or flotation is possible (not possible). After testing in the collector solution, the mineral was removed, washed, and tested by the captive-bubble method in water, or floated in a cylinder with frother only. In this way the composition of solutions in which a mineral was conditioned but in which properties of the collector solution prevented contact or flotation can be defined. The composition of solutions in which conditioning was possible lie between the full and broken curve, the experimental results being indicated on the figures by a square. The curves show the limits of composition of solution in which flotation in a cell would be possible. Many factors other than those considered in these tests determine recovery or grade of a given mineral in practice.

Jan 1, 1947

Separates of all the Technical Publications published in 1931 are available at Institute headquarters. All the papers are on file in public, university and technical libraries, and when so indicated in the list, may be found in the Transactions. Copies of these papers have been mailed to those members of the Institute who are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Institute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Additional copies are sold at the rate of I cent per page; minimum charge, 25 cents. Metal Mining Tech-nical Publi- Title Author Meeting TRanb. cation Volume No. and Page* 411-A.43 Ventilation at the Portovelo Mines, J. P. Harmon New York. T31, 83 Ecuador (18) Feb., 1931 425-A.44 Use of Models for the Study of Mining P. B. Bucky New York, Problems (28) Feb., 1931 Milling and Concentration 375-B.32 Ball Mill Studies, I (53) A. W. Fahrenwald New York, H. E. Lee Feb.. 1931 401-B.33 Experimental Flotation of Oxidized H. S. Gieser New York. Silver Ores (9) Feb., 1931 410-B.34 Flotation of Minor Gold in Large-scale E. S. Leaver New York, Copper Concentrators (32) J. A. Woolf Feb., 1931 414-B.35 Effect of Particle Size on Flotation A. M. Gaudin New York, (23) J. 0. Groh Feb., 1931 H. B. Henderson 416-B.36 Ball Mill Studies, 11.—Thermal A. W. Fahrenwald New York. Determinations of Ball Mill Effi- G. W. Hammar Feb., 1931 ciency (13) H. E. Lee W. W. Staley Iron and Steel Division 38QC.59 Open-hearth Steel Process as a Prob- E. R. Jette New York, C31, 80, 111 Iem in Chemical Kinetics (34) Feb., 1931 381-C.60 Thermodynamic Study of the Phasial Yap, Chu-Phay New York. Equi1ibriain the System Iron-car- Feb., 1931 bon (26) 382-(3.61 Influence of Dissolved Carbide on the Yap, Chu-Phay New York, Equilibria of the System Iron-car- Feb., 1931 ban (19) 383-C.62 Research on Blast-furnace Slags. R. S. McCaffery New York, Three papers (88) Co-workers Feb., 1931 384-C.63 Statistical Analysis of Blast-furnace K. S. McCaffery New York, C31, 60, 70 Data (13) R. G. Stephenson Feb., 1931

Jan 1, 1931

By C.P. Clingerman

The recent iastallation of a combination dust catcher, gas washer and precipitator at Carrie blast furnaces of the Homestead Steel Works has given very satisfactory results. The following description of the gas-cleaning installation is based on actual operating experience. When Carrie blast furnace No. 3 was rebuilt the decision was made to fine-clean all the gas produced by the furnace, because the management wanted fine-cleaned gas for fuel in the stoves and boilers. In order to keep the installation cost as low as possible, the gas-cleaning system was streamlined. All by-pass lines and goggle valves for bypass lines were eliminated from the system. A radical departure from the use of 8-in. tubes in the Cottrell-type precipitators was made by using 12-in. diameter tubes in a single compartment, the single compartment being divided into two units by a single partition wall in the top header. The Furnace Proper A few of the characteristic points and dimensions of the furnace proper are: Hearth diameter.............. 26 ft. o in. Bosh diameter............... 29 ft. 1 3/4 in. Stock-line diameter........... 20 ft. o in. Large-bell diameter........... 14 ft. 8 in. Small-bell diameter........... 6 ft. 6 in. Height of furnace from center of iron notch to bottom of large bell, closed............ 94 ft. 4 in. Height of furnace from center of iron notch to main platform ...................... 105 ft. o in. The furnace top is equipped with a MC-Kee revolving distributor, the operation of which is electrically interlocked with the skips, bell hoists, and coke-weighing and charging apparatus through a Freyn automatic charging control. The gas leaves the furnace first through four offtakes, 5 ft. 9 in. in diameter, then through uptakes that, are approximately 85 ft. high, which feed into a single down-comer that is 9 ft. in diameter. Dust Catcher The primary dust catcher installed (Fig. I) may be described as a single-cone type. The inlet pipe at the top of the dust catchei is 9 ft. in diameter; it is flared to a conical shape as it extends down inside the dust-catcher shell, which is 35 ft. in diameter, 37 ft. high on the straight side, and has a conical top and bottom. The slope of the bottom is so0 with the horizontal. The cone-shaped pipe inside the dust-catcher shell is 42 ft. high and is 19 ft. 7 in. in diameter at its bottom lip where it releases the gas inside the dust catcher. The ratio of the area of the inside cone at its bottom lip to the

Jan 1, 1943

By C. P. Clingerman

The recent iastallation of a combination dust catcher, gas washer and precipitator at Carrie blast furnaces of the Homestead Steel Works has given very satisfactory results. The following description of the gas-cleaning installation is based on actual operating experience. When Carrie blast furnace No. 3 was rebuilt the decision was made to fine-clean all the gas produced by the furnace, because the management wanted fine-cleaned gas for fuel in the stoves and boilers. In order to keep the installation cost as low as possible, the gas-cleaning system was streamlined. All by-pass lines and goggle valves for bypass lines were eliminated from the system. A radical departure from the use of 8-in. tubes in the Cottrell-type precipitators was made by using 12-in. diameter tubes in a single compartment, the single compartment being divided into two units by a single partition wall in the top header. The Furnace Proper A few of the characteristic points and dimensions of the furnace proper are: Hearth diameter.............. 26 ft. o in. Bosh diameter............... 29 ft. 1 3/4 in. Stock-line diameter........... 20 ft. o in. Large-bell diameter........... 14 ft. 8 in. Small-bell diameter........... 6 ft. 6 in. Height of furnace from center of iron notch to bottom of large bell, closed............ 94 ft. 4 in. Height of furnace from center of iron notch to main platform ...................... 105 ft. o in. The furnace top is equipped with a MC-Kee revolving distributor, the operation of which is electrically interlocked with the skips, bell hoists, and coke-weighing and charging apparatus through a Freyn automatic charging control. The gas leaves the furnace first through four offtakes, 5 ft. 9 in. in diameter, then through uptakes that, are approximately 85 ft. high, which feed into a single down-comer that is 9 ft. in diameter. Dust Catcher The primary dust catcher installed (Fig. I) may be described as a single-cone type. The inlet pipe at the top of the dust catchei is 9 ft. in diameter; it is flared to a conical shape as it extends down inside the dust-catcher shell, which is 35 ft. in diameter, 37 ft. high on the straight side, and has a conical top and bottom. The slope of the bottom is so0 with the horizontal. The cone-shaped pipe inside the dust-catcher shell is 42 ft. high and is 19 ft. 7 in. in diameter at its bottom lip where it releases the gas inside the dust catcher. The ratio of the area of the inside cone at its bottom lip to the

Jan 1, 1943

By Wilbur S. Burbank, Robert G. Leudke

The impressive western San Juan Mountains of Colorado were carved by Pleistocene and Recent erosion from a thick blanket of Tertiary volcanic rocks that rests upon a basement of metamorphic, sedimentary, and igneous rocks ranging in age from Precambrian to Tertiary. These rocks record a long, complex, and fairly complete sequence of geologic events that have affected the region through much of geologic time. The geologic history of the region includes several periods of deformation, erosion, and igneous activity; closely associated with two of these periods were two periods of mineralization. The older of these was related to Late Cretaceous-early Tertiary (Laramide) intrusive activity, and its deposits occur in the older sedimentary units. The younger, of later Tertiary age and related to the widespread middle Tertiary extrusive and intrusive activity, is the chief concern of this paper. Tertiary volcanism built a great plateau surrounding the San Juan volcanic depression, a complex of subsided crustal blocks in the vent areas. The Silverton and Lake City cauldrons, nested within the larger depression, were domed by resurgent magma that created keystone grabens along the distended crests of the domed floors and many postcauldron radial and concentric fractures, dikes, and intrusive plutons within and marginal to the cauldron sites. The postvolcanic evolution of large quantities of gases, chiefly carbon dioxide and water, propylitically altered the rocks in and around the volcanic depression prior to the younger period of ore deposition. The ore deposits, localized mainly in the radial and concentric fractures about the cauldrons and in the associated graben faults, include fissure veins, chimneys, replacements, and disseminations in volcanic and underlying basement rocks. Fissure veins, constituting the major economic source, yielded precious- and basemetal ores. Most veins are compound with sphalerite, galena, and chalcopyrite; some veins contain silver-bearing arsenical sulfosalts and free gold. These minerals occur in predominantly quartz gangue. However, gangues composed of several manganese silicates and carbonates and relatively· barren of metals are abundant locally and probably originated by alteration of rocks at roots of faults and fissures during evolution of carbonatic solutions. The bulk of the ores are hypogene and probably had their source in deep parent magmas of the shallow eruptive rocks. Total production since the early 1870's has exceeded half a billion dollars in recovered metals, with a ratio of precious- to base-metal values of about 3 to 2. Since 1930, improvements in metallurgical treatment and mining techniques have increased the base-metal yield.

Jan 1, 1968

SME Membership Directory Listings of record March 31, 1072 SOCIETY OF MINING ENGINEERS OF AIME

Jan 7, 1972

By H. O. HOPMAN

(Canal Zone Meeting, November, 1910.) I. INTRODUCTION. THE substance of this paper was prepared for the Seventh International Congress of Applied Chemistry, held in London, May, 1909, under the title, Some Developments in Blast-Roasting. In the absence of the author, a -short abstract of the paper was read, and the abstract only will appear in the proceedings of the congress. The present paper has been partly rewritten and considerably enlarged by information gained since the original was prepared ; also some illustrations have been added. Blast-roasting' is a generic term for the process of forcing air through finely-divided. metallic sulphide with the object of roasting and agglomerating in a single operation. At first the process was confined to a galena-concentrate ; lime, limestone, or gypsum was added, to serve both as a diluent to keep separate the particles of galena that they might be thoroughly oxidized, and as a flux that the partly-roasted ore might be agglomerated by the formation of some slag. Later it was extended to treat other metallic sulphides. The leading processes were the Huntington-Heberlein and the Savelsberg of Europe, and the Carmichael-Bradford of Australia. In the United States and Canada, the Huntington-Heberlein process has found application in some instances with galena-concentrates, for which it was originally intended; but this class of ore is not often treated alone, hence the process has had to be modified to suit conditions. The Savelsberg process has been transplanted to this country in about its original form. The Carmichael-Bradford is not used at present. The changes called for in the Huntington-Heberlein process to adapt it to the class of lead-bearing ores usually smelted have been the 1 A. S. Dwight, Engineering and Mining Journal, vol. lxxxv., No. 13, p. 649 (Mar. 28, 1908).

Jun 1, 1910

By B. E. Eakin, A. L. Lee, M. H. Gonzalez

Expeximental viscosity and density data of lour natural gases are presented for temperatures from WO to 340F and pressures from 100 to 8.000 psia. A correlation is also discussed and results reported. INTRODUCTION This investigation is one of several efforts by the authors to provide viscosity data for pure hydrocarbons and mixtures. Results of some pure hydrocarbons and their mix tures have been presented." Several predictive methods and correlations have also been reported.'," This paper presents the experimental viscosity and density data of four natural gases and confirms a correlation in a previous study. APPARATUS The viscometer was described previously. 2,6 A bank of stainless steel pycnometers was included to determine density in conjunction with the viscosity measurements (Fig. I). DATA AND MATERIALS The natural gases were furnished by the Atlantic Richfield Co. (Samples 1 and 21, the Continental Oil Co. (Sample 3) and the Pan American Petroleum Corp. (Sample 4). Table 1 shows the composition of these gases obtained by mass spectrometer analysis. The pure component viscosity data used in the correlation have been published."".'"', '" Experimental and calculated viscosity data for the natural gases are presented in Tables 2 through 5. CORRELATION Starling and Ellington"' have reported several semi-empirical expressions based to a certain extent on the theory of viscosity advanced by Born and Green.' The final expression presented by Starling and Ellingto'n is: i'. (micropoise) -- /t,, exp rX(7') p ..... (I) Eq. 1 was modified by Lee et 01." to represent mixture and pure component data simultaneously. This equation has the form: F = K exp [XpY] :.........(2) where K=- (7.77 i 0.0063M)Ti 122.4 + 12.9M +T .................(3) ' ' ' X= 2.57 + ---1914.5+ 0.0095M .... (4) Y = 1.11 -r 0.04 X ........(5) Over the pressure and temperature range studied in this investigation, this equation represents the data on methane, ethane, propane, n-butane and four methane-n-butane mixtures with a standard deviation* of ? 1.89 per cent. Density data by Sage and Lacey" were used to fit the equations. Eq. 2 gives reliable values of the viscosity of light hydrocarbons without prior knowledge of experimental viscosity values, but accurate density data must be available. Eq. 2 was used to predict viscosity values for the natural gases studied in this paper. The particular set of parameters contained in Eqs. 3 through 5 gave values that reproduced experimental data within 25 per cent. Needless to say, in using Eq. 2 better density values will give better viscosity results. However, those engineers who do not have accurate density values at hand or the time, or such facilities as a library, computer, etc. readily available, may feel uneasy in using Eq. 2. Therefore, the authors sought the easiest but by no means best density prediction method, which was reported by Kaf 30 years ago. A set of density values, which were calculated based on Kay's method, and a generalized compressibility factor chart were used to fit Eq. 2. The results are:

Jan 1, 1967

By M. C. Manderson

The sharp drop in world phosphate demand that took place in 1975 due to temporarily high prices, now seems to be reversing itself. And prices for both phosphate rock and phosphate fertilizers, which declined dramatically from their 1975 highs, now appear to be bottoming out. This recent price weakness has delayed new mining ventures that had been planned for completion by around 1980. While there is ample capacity to supply near-term rock needs, the stage seems to be emerging for a better supply-demand and price environment in the late 1970's and early 1980's.

Jan 1, 1979

By Douglas J. Harvey

The surface tension of lead-tellurium alloys (in the range 0 to 6.70 at. pct Te) ad lead-arsenic alloys (in the range 0 to 10.53 at. pct As) has been examined by the maximum bubble pressure method. The surface tension of high purity lead can be expressed over a range of temperatures (M.P. to 750°C) by the relationship = 512 — 0.133t. Arsenic and lellurium were both found to be surface active in lead. The surface excess concentration at 700°C was .found to be constant at 0.74 x 10-10 moles per sq cm for tellurium. The surface excess of arsenic at 700°C varied between 0.26 x 10-10 moles per sq cm at 0.16 at. pct to 1.5 x 10-10 moles per sq cm at 8.3 at. pet. The surface tension of lead has been investigated sporadically over the last 90 years. The first recorded study was made by Quincke1 who used a rather crude application of the drop-weight method. Hogness2 obtained the first reliable value for the surface tension of lead by measuring the pressure necessary to force the liquid metal from the end of a small capillary of known radius. Hogness gives the empirical formula: ?(surface tension)= 444 - 0.077 (l-327) which describes the relationship between surface tension and temperature ("C); This work was followed by that of Bircumshaw3 who applied the two-capillar maximum bubble pressure method of Sugden.4 The values published by Bircumshaw are in good agreement with those found by Hogness. Matuyama5 examined the surface tension of lead by the drop weight method. However, the values found are somewhat higher than those previously reported. More recent investigations by Greenaway6 and by Melford and oar' have resulted in data which are not in close agreement, but which are well within the expected range at most temperature levels. The study of the surface tension of lead alloys began with Drath and sauerwald8 who examined the lead-bismuth system. They found that the surface tension values of the alloys in this system deviated only slightly from the ideal mixture rule. Matuyarna5 examined the lead-antimony system. Bircumshaw the lead-tin, and the lead-indium system was studied by Hoar and Me1ford.10 The results of these investi- gations are summarized in Fig. 1. It may be seen that the data vary only slightly from the ideal mixture rule. As none of the metals studied and reported in the literature has a very interesting effect on the surface tension of lead,*the next logical step might be to examine the effect of metals of low solubility or nonmetals having some liquid solubility. Baes, and Kellogg11 have pointed out that the elements most likely to be surface active in liquid metals are ones of limited solubility in the liquid state and possessing weak intermolecular bonding forces in the solid state. Therefore, Group V, VI and VII nonmetals are most likely to be surface active. It was decided to examine the effect of a borderline metal, arsenic, and a nonmetal tellurium. Arsenic forms a eutectic with lead having a melting point of 290°C and a composition of 6.9 at. pct As.13 Pure arsenic sublimes when heated above 610°C. Even though alloying with lead lowers the vapor pressure, fumes containing arsenic are evolved at a very noticeable rate when lead-arsenic alloys are heated above 650°C. Tellurium raises the liquidus temperature of lead sharply to 904°C,14 the melting point of PbTe (lead-telluride). The solid solubility of tellurium in lead was determined by Greenwood and worner15 to be 0.0007 at. pct at room temperature. EXPERIMENTAL METHOD Surface Tension Measurement—The two capillary maximum bubble pressure method for measuring surface tension developed by Sugden,4 and used later

Jan 1, 1962

By R. M. Asimow, J. J. Svitak

Tile crilical resoll,r,d shear stress, CRSS, for slip of slow1y cooled Ag-All single crystals was measured at 201K. Tlze importance of short-range order and Suzuki sogregalion was inrestigated by deter~rlining llze ciic.cl of quenching on the CRSS. Thr obserz.ed rfrtenching effects were generally small and indicate that short-range ordcr and Slczuki srgregation do no1 account for n significant portion of the solid-solution strengthening in this system. However, all alloys slzozcwi yield drops ulhich rilere heat- lreat nrenl-sensiline THERE have been a number of mechanisms proposed to explain alloy strengthening in the Ag-Au system. The effectiveness of some of the proposed mechanisms, especially those that depend on Suzuki segregation1" or on short-range order,2-6 SRO? should be strongly dependent on heat treatment. Since internal friction investigations in this system indicate that there is stress-induced order,' we must also consider the possibility of local atomic rearrangement or short-range ordering in the stress field of a dislocation. There is not complete agreement whether these mechanisms should be most effective in raising the flow stress, in causing yield drops. or some combination of these two effects. This work was undertaken to determine the effects in the Ag-Au system of mechanisms that depend on segregation or order by using known but drastically different cooling rates following a high-temperature treatment. By comparing the critical resolved shear stress, CRSS, for slip measured after a very slow cool and again after a fast cool (quench) of the same crystal, it is possible to determine the effect of cooling rate on CRSS* and on yield drops. The single-crystal CRSS was determined at several compositions because there has been no data published across the phase field since the publication of room-temperature flow stress by Sachs and Weerts.' EXPERIMENTAL PROCEDURE Starting with materials of 99.999 pct purity, single-crystal specimens of random orientation 1.25 mm square by 4 cm long were prepared with 0, 10, 14, 25, 30. 50, 70. 75. 80, 90. and 100 at. pct Au. Crystals were grown in an inert atmosphere using a modified Bridgman technique with a growth rate of 1.5 cm per hr in a gradient of 3°C per cm. To obtain a maximum practical degree of SRO, the crystals were cooled at a rate of 275'C per hr to about 310°C and then cooled at 6°C per hr to approximately 200°C. Specimens were tested in tension immersed in an alcohol bath at -72°C (201°K) at a strain rate > = 0.003 mm"1 to determine the CRSS (7). The activation volume of several crystals was determined from the flow stress increment (72 - T1) for a tenfold increase in strain rate. The total shear strain varied from 0.05 to 2.3 pct but was generally less than 0.4 pct. After testing, each crystal was then held at 500°C for 10 min, quenched into brine at -35°C and. after storage at -71°C for 1 day, retested in tension using a procedure identical to that of the first test. The quenching apparatus, see Fig. 1, was designed to enable accurate temperature control and rapid quenching while preventing specimen contamination and accidental deformation. Test data from a specimen with a fine thermocouple spot-welded to it indicated a cooling rate of 104C per sec. The relatively low heat-treatment temperature was chosen to minimize quenching defects caused by a large vacancy

Jan 1, 1970

By C. W. Allen, L. C. Moore

THE Mather mine, of the Negaunee Mine Co., is within the limits of the City of Ishpeming, on the Marquette iron- range in Michigan's Upper Peninsula. It is named for William G. Mather, who has served as President, and Chairman of the Board, of The Cleveland-Cliffs Iron Co. for well over 50 years. The property comprises nearly the square mile of section 2, T.47 N. R.27 W., which, except for 20 acres in the northeast corner, was leased by The Cleveland-Cliffs Iron Co. to the Negaunee company. The latter is a partnership of Cleveland-Cliffs and the Bethlehem Steel Co., organized to equip the property, retaining Cliffs in charge as operator. Shipments of ore from this area are mainly through Marquette, which is 16 miles to the northeast on Lake Superior, or through Escanaba, a Lake Michigan port, 65 miles to the south. Cleveland-Cliffs, in 1943, operated 12 mines in the Lake Superior district, with shipments of 6,635,576 tons for the year. GEOLOGY The north footwall of the Marquette Range synclinorium outcrops near the north line of sec. 2, the iron formation dipping to the south at an angle of about 40º. The south side of the trough reappears at a distance of 4 ½ miles on sec. 26 and the surface geology between shows iron formation or intrusive diorites. The latter are harder than most phases of the iron formation and, as a result of glacial action, appear as buttes or low-lying hills. The general elevation of sec. 2 is about 1450 ft. above sea level, or 850ft. above Lake Superior, and the higher diorite outcroppings about 1600 ft. above sea level. The geological structure has been complicated by a series of major and minor faults, one of which may be illustrated by the diorite sheet, which tilts south with the iron formation in the north half of the section and then reappears near the center to repeat this sequence. Sectionally the geological series includes a nearly eroded capping of Goodrich quartzite followed by the considerable thickness of Negaunee iron formation, which is cut by intrusive dikes or diorite sheets, and underlain by the Siamo slates grading into quartzites. The ore deposits occur mainly in troughs formed by the intersection of impervious dikes and the footwall slate, but include locally enriched lenses or bands in the iron formation and also interbedded with the Siamo slate. The ore is a soft red hematite with an indicated dried analysis from the surface drilling to date of 61.50 per cent Fe, 0.134 per cent P, 5.40 per cent Si, 2.87 per cent Al and 0.015 per cent S. EXPLORATION A diamond-drilling campaign started in 1937 actually had its inception in 1917, when a number of shallow test holes were put down for the purpose of locating ore that might be quickly developed and mined

Jan 1, 1945

By William Campbell

(Cleveland Meeting, October, 1912.) THE structure of iron and steel, though the object of so much study and research for the past 25 years, is by no means thoroughly understood. In the first place, we have three or more distinct iron-carbon thermal diagrams, each with its own supporters, and each representing a theory of the structure and constitution of cast-iron. In the second place, by reason of the fact that austenite, the solid solution of carbon in iron, decomposes in the solid state into ferrite, or pure iron, and cementite (Fe3C), and that quenching from above this transition-range, no matter how rapid, cannot entirely prevent the change and thus preserve the austenite by itself at ordinary temperatures, it happens that under the microscope we find, in addition to the ferrite, Fe3C, and austenite, which the thermal diagram of steel requires, it series of transition-products with distinctive structures, to which have ,been given the names martensite, troostite, sorbite, etc. Now these transition-products, in addition to the solid solution, austenite, have been the source of much controversy, at times very bitter. One side would insist that, say, troostite was an entity, which the other side would deny, pointing out that it must be a transition-mixture, with a particular structure. That austenite was a solid solution of carbon in iron has been denied by one school ; we have been told that Fe24C dissolved both Fe3C and Fe, and thus gave rise to a whole series of quenching-products-all this in spite of the fact that no matter how the thermal diagrams differ in regard to cast-iron, they all agree in regard to the solid solution, austenite, for Fe24C finds no place on the diagram. Thus it happens that while the authorities fight both in regard to the iron-carbon diagram and the structures met with in hard- * Associate Professor of Metallurgy, Columbia University in the City of New York.

Dec 1, 1912

By C. A. Stetefeldt

FoR the convenience of those who do not care to enter into the details of this long essay, I begin with a summary of the most important results it presents. The extraction of silver by the lixiviation-process from ores which have been subjected to a chloridizing-roasting, is based upon the fact that silver chloride is easily soluble in solutions of sodium or calcium hyposulphite, and that silver is precipitated from such solutions by an alkaline sulphide, with regeneration of the hyposulphite salts. In case the ore contains lead a large portion of the latter is and dissolved, lead sulphate being soluble in hyposulphite solutions. If, at the same time, copper is present, the sulphides precipitated from the solution, contain silver, copper, and lead, a combination of metals not desirable for subsequent treatment. Mr. E. H. Russell, of Park City, Utah, is the inventor and the patentee in the United States and several foreign countries of a new lixiviation-process, based upon the chemical facts discussed in this paper. Mr. Russell has discovered that lead can be completely separated from a sodium hyposulphite solution, as lead carbonate, by sodium carbonate or purified soda-ash, without precipitating any copper or silver. After decanting the solution from the lead carbonate, silver and copper are obtained from it in the usual way. This method of separating lead prohibits the use of calcium poly-sulphide as a precipitant for the sulphides, because any calcium entering the regenerated lixiviationsolution would also be precipitated as a carbonate with the lead by soda-ash. Hence, a sodium sulphide must be employed. A full investigation has demonstrated that this is by no means detrimental. Sodium sulphide and hyposulphite are more advantageously used in the lixiviation-process than the corresponding calcium-salts. Another defect in the lixiviation-process consisted in the necessity of a very perfect chlorination of the silver in the ore, because silver in

Jan 1, 1885

By H. W. McQuaid, E. W. Ehn

It is usually assumed that chemical specifications are sufficient for steel to be used for case carburizing, and if the steel analyzes within the ordinary limits specified for steel for this purpose, no difficulty traceable to the steel used should be encountered in obtaining satisfactory results in the case carburizing and hardening. Much work has been done to determine the effect of various alloying elements on the rate of carbon penetration, etc. but, to our knowledge, little if anything has been published in regard to the effeet of the quality of the steel on the final results in the hardening of case-carburized steel parts. The writers believe that the structure of the case both before and after quenching is greatly affected by the actual condition of the steel itself as made, and that for good results in the case-carburizing and hardening departments, the steel should be of the best possible quality as regards non-metallic impurities. It is the purpose of this paper to prove that the presence of excess dissolved oxides in the steel, as made in the melting furnace, affects permanently the results obtained in carburizing and hardening and that it is possible that the presence of dissolved oxide call result in total unfit-ness of low-carbon steel for case hardening purposes. When races and rolls for roller bearings are made from a low-carbon steel, case carburized and hardened, it is of primary importance that the results of this treatment be of the highest quality. It is necessary, therefore, that in the case-carburizing work each detail be rigorously checked to avoid any defects which would cause the loss of much time and material. The case carburizing with which this paper deals was done in under-fired oil furnaces. The temperature of each furnace is controlled by means of a platinum platinum-rhodium thermocouple, in connection with a potentiometer indicator and potentiometer recorder. The temperature of each furnace is registered every 15 min. by an operator, who is continually checked by the automatic recorders.

Jan 1, 1922