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By A. S. Nowick, E. S. Machlin

ONE of the main criteria used to rate the heat-resisting properties of alloys is stress rupture.1 During a stress-rupture test a tensile specimen is held under a constant load at a constant temperature until it fractures. The chief measurement made during this test is the time required for rupture at the specific test stress and temperature. It was found empirically from a series of stress-rupture tests at a constant temperature that when the logarithm of the time for rupture is plotted against the logarithm of stress a straight line is obtained within experimental error.2~3 This method of showing stress-rupture data has been adopted by many investigators and the KACA.4 By interpolation and extrapolation from these plots, values of the stresses required to rupture the specimens (the rupture strengths) in 10, 100, and 1000 hr are obtained for specific temperatures. Alloys are then rated for a particular application on the basis of their rupture strengths at the rupture life that most nearly represents the application. Inasmuch as stress rupture is an important criterion in rating heat-resisting alloys, it would be advantageous to know the quantitative dependence of the time for rupture on stress, temperature, com- position, and structure. In order to obtain this information, an investigation was made at the KACA Cleveland laboratory during the spring of 1945. The theory of rate processes was used because it has been found to apply to certain processes such as chemical reactions, viscous flow, and creep that occur at a definite rate for given conditions. It was thought that stress rupture was such a process. An equation was derived that gives, for a given com- position and structure, the dependence of the time for rupture on stress and temperature. The investigation is part of a general program to provide information that will lead ultimately to the development of better alloys in order that the efficiency and power output of gas turbines used in aircraft propulsion can be increased. THEORY The theory of rate processes will first be discussed as a general theory. It will then be shown that if stress rupture of heat-resisting alloys can be treated as a rate process, certain equations must be satisfied. Later sections will then show that these equations are satisfied. General Theory of Rate Processes The theory of rate processes5 eveloped by Eyring and others has been applied to chemical reactions as well as to other processes such as viscosity of liquids and diffusion. In every case in which rate- process theory can be applied, there is a small subdivision, so that the macroscopic process is the net effect of all the small processes. This smallest subdivision is called the "unit process.'' For example, in a chemical reaction the unit process is

Jan 1, 1947

By Alfred H. Bell, George V. Cohee

In 1941 Illinois produced 134,139,000 bbl. of oil, or 9.5 per cent of the total for the United States, and ranked fourth among the states. The production for 1941 declined 9.2 per cent from the previous year's total of 147,647,000 bbl. Daily average production for 1941 was 366,000 bbl. At the beginning of the year daily production was slightly more than 326,000 bbl. and it remained at appoximately that amount until June, when there was a slight increase. The increase continued until the peak of 431,260 bbl. daily was reached for the week ending Oct. 4. Daily average production at the end of the year was approximately 387,500 barrels. The increased production during the last half of 1941 was largely due to the rapid development of the Johnsonville field, Wayne County, the Rural Hill field, Hamilton County, and the Benton field, Franklin County—new fields discovered in the current year (Fig' 1)—and the Woodlawn pool, discovered in 1940. Discoveries In 19 counties in southern Illinois, 44 new fields were discovered in 1941 (Fig. 2 and Table 2), and extensions to 40 fields were successfully completed (Table 3). At the end of the year there were 10,496 wells in the fields discovered since Jan. I, '937, as compared with 71965 wells at the end Of '940. The area proved for production in the new fields increased from 78,040 acres at the beginning of 1941 to 97,483 acres at the end of the year (Table I)—an increase of 19,433 acres, of which 9,955 acres are in the fields discovered during the current year, and the remainder of 9,478 acres in extensions to pools discovered earlier. Drilling During the past year, 3838 wells were completed in Illinois (Table 4), of which 2912 were oil producers, 13 were gas producers and 913 were dry holes; 76 per cent of the wells drilled were producers. Of the total number drilled, 591 wells are classified as "wildcat" and of these 84 (1 in 7) were successful in obtaining production. The results of an investigation to ascer-tain the reason for the locations of the wildcat wells are set forth in Table 5. Of the 591 wildcat wells, the 292 known to have been located by scientific methods were 21.6 per cent successful. The total footage of wildcat wells drilled in 1941 was 1,341,743 ft., of which a total of 216,995 ft. was drilled in successful wells. Exploration MEthods Subsurface geology and geophysics, largely the reflection seismograph, are still the principal methods used in exploration and development in the state. The number of seismograph parties operating throughout the year was as follows: seven parties on Jan. I, 1941; five on Apr. I; four On July I; eight on Oct. I; fifteen on Jan. 1: 1942.

Jan 1, 1942

By Alfred H. Bell, George V. Cohee

In 1941 Illinois produced 134,139,000 bbl. of oil, or 9.5 per cent of the total for the United States, and ranked fourth among the states. The production for 1941 declined 9.2 per cent from the previous year's total of 147,647,000 bbl. Daily average production for 1941 was 366,000 bbl. At the beginning of the year daily production was slightly more than 326,000 bbl. and it remained at appoximately that amount until June, when there was a slight increase. The increase continued until the peak of 431,260 bbl. daily was reached for the week ending Oct. 4. Daily average production at the end of the year was approximately 387,500 barrels. The increased production during the last half of 1941 was largely due to the rapid development of the Johnsonville field, Wayne County, the Rural Hill field, Hamilton County, and the Benton field, Franklin County—new fields discovered in the current year (Fig' 1)—and the Woodlawn pool, discovered in 1940. Discoveries In 19 counties in southern Illinois, 44 new fields were discovered in 1941 (Fig. 2 and Table 2), and extensions to 40 fields were successfully completed (Table 3). At the end of the year there were 10,496 wells in the fields discovered since Jan. I, '937, as compared with 71965 wells at the end Of '940. The area proved for production in the new fields increased from 78,040 acres at the beginning of 1941 to 97,483 acres at the end of the year (Table I)—an increase of 19,433 acres, of which 9,955 acres are in the fields discovered during the current year, and the remainder of 9,478 acres in extensions to pools discovered earlier. Drilling During the past year, 3838 wells were completed in Illinois (Table 4), of which 2912 were oil producers, 13 were gas producers and 913 were dry holes; 76 per cent of the wells drilled were producers. Of the total number drilled, 591 wells are classified as "wildcat" and of these 84 (1 in 7) were successful in obtaining production. The results of an investigation to ascer-tain the reason for the locations of the wildcat wells are set forth in Table 5. Of the 591 wildcat wells, the 292 known to have been located by scientific methods were 21.6 per cent successful. The total footage of wildcat wells drilled in 1941 was 1,341,743 ft., of which a total of 216,995 ft. was drilled in successful wells. Exploration MEthods Subsurface geology and geophysics, largely the reflection seismograph, are still the principal methods used in exploration and development in the state. The number of seismograph parties operating throughout the year was as follows: seven parties on Jan. I, 1941; five on Apr. I; four On July I; eight on Oct. I; fifteen on Jan. 1: 1942.

Jan 1, 1942

By Hermann Schmalzried, Carl Wagner

UPON heating a metal oxide or sulfide in H2, first only oxygen or sulfur is removed from the surface. Thus the metal/nonmetal ratio in the oxide or sulfide increases and the thermodynamic activity of the metal increases accordingly. For the formation of metallic nuclei, a certain super saturation is necessary, i.e., the activity of the metal must become greater than unity. Once nuclei of the metal have been formed, the supersaturation is supposed to decrease. Even under steady-state conditions of a reduction process, however, the activity of the metal inside an oxide or sulfide phase must be greater than unity in order to have a driving force for the individual steps of the reduction process. As an example, consider the reduction of Ag2S with a high mobility of cations and electrons. As shown schematically in Fig. 1, the reduction process involves the following steps:' 1) sulfur removal along the entire Ag2S surface in form of H2S, 2) migration of Ag' ions and electrons from the Ag2S surface to nuclei of metallic silver, 3) transfer of Ag+ ions and electrons from the Ag2S phase to the metal. For a finite rate of step 3, the activity of silver in Ag2S next to the Ag2S-Ag interface must be greater than unity. Moreover, for a finite rate of step 2, the activity of silver at the gas-Ag2S interface must be still somewhat greater. Theoretical considerations lead to the tentative conclusion that at least under steady-state conditions the supersaturation will be rather low.' To test this conclusion, the average activity aAg of silver in a Ag2S tablet about 2 mm thick with a diameter of 5 mm was followed as a function of time by measuring the electromotive force E of the cell Pt I Ag | Agl I Ag2S I Pt where AgI is used as a solid electrolyte in which only Ag+ ions are mobile. The activity aAg is calculated as aAg=exp(-EF/RT) Since the diffusion coefficient for transport of silver in Ag2S is very high (- 3 . l0-2 sq cm per sec),3 the average activity aAg is representative for both the bulk and the surface of the Ag2S tablet. Experiments were conducted at about 400°C. The cell was surrounded by an aluminum block in order to secure a uniform temperature and to eliminate thermoelectric effects. With the help of a potentiometer, first a potential of 0.16 v was applied to the above cell in argon in order to obtain a well defined initial state with a Ag/S ratio close to 2.000.~ Then the cell was disconnected from the potentiometer and a gentle stream of H2 was passed along the Ag2S surface. In view of the removal of sulfur in form of H2S, the electromotive force E decreased within 20 to 30 min to zero corresponding to a Ag/S ratio of 2.003 and became negative, indicating a value of aAg> 1. A representative plot electromotive force E vs time is shown in Fig. 2. The minimum of the electromotive force characteristic of the onset of

Jan 1, 1963

By H. O. Hofman

(Canal Zone Meeting, November, 1910.) I. INTRODUCTION. IN a previous paper,1 The Behavior of Calcium Sulphate at Elevated Temperatures with Some Fluxes, we published the results of our investigation, into the behavior of calcium sul-phate in air; that, is, under oxidizing conditions. The results as a whole hold good for a neutral atmosphere, or one which has no chemical effect upon calcium sulphate. The present paper deals with the behavior of calcium sulphate under reducing conditions, the reducing-agents employed being carbon monoxide and carbon, and the changes the calcium sulphide formed undergoes when it is subjected to an oxidizing-roast. Technical literature deals very sparingly with the subject. The information furnished by the recent leading chemical manuals is general. Thus Dammer,2 Moissan,3 and Abbegg,4 quote Berthier as having reduced, in 1823, calcium sulphate with carbon, and Stammer as having done the same in 1851 with carbon monoxide; Gmelin Kraut 5 add Leplay and Laurent (1848) as third investigators. Metallurgical authorities confine their statements to the known fact of reduction by carbon. II. PREPARATION OF RAW MATERIALS. 1. Calcium Sulphate.-This salt was prepared in the same manner as described in our previous paper,6 and was found to be chemically pure. * Professor of Metallurgy, Massachusetts Institute of Technology. + Metallurgical Instructor, Imperial Technological Institute. 1 Trans, xxxix., 628 to 653 (1909). 2 Handbuch der anorganischen. Chemie, vol. ii., part 2, p. 309 (1894). 3 Traité de Chimic Minérale, 1904, vol. iii., p. 543. 4 Handbuch der anorganischen Chemie, vol. ii., part ii., p. 116 (1905). 5 Handbuch der anorganischen Chemie, vol. ii., part 2, p. 233 (1909). 6 Trans., xxxix., 630 (1909).

Nov 1, 1910

By W. J. Millard

IT is well known that the excellent mica from Brazil played a most vital role in World War II. Increased production from Brazil was necessary and with the assent of the Brazilian Government engineers from the United States went down to study the problem. One of the means advocated by a former Chief of Metals and Minerals Branch of the Board of Economic Warfare, Mr. Carl Schwegler, was the use of stripping machinery. On a pegmatite dike favorable for stripping, a small number of miners could produce as much mica per day as an underground mine employing many times the same number of men. TYPE OF DEPOSIT FAVORABLE The most favorable type of pegmatite for stripping is that which lies more or less parallel to the surface of the slope of a hill. Pegmatite dikes that cut directly into a hill are not suitable for stripping except where a long outcrop extends along the slope. Then just the outcrop could be stripped to some advantage. The ratio at no time should be greater than I:3; i.e., I cu. m. of pegmatite to 3 cu. m. of waste, unless the pegmatite was extremely rich throughout the dike. THE ECONOMICS OF STRIPPING When a mineral is badly needed to win a war, not too much heed can be paid to costs. The object is to produce rapidly and in quantity. Again, a deposit containing a superior grade of mica may be worked although the pegmatite is more costly to work than another deposit containing a considerably greater amount of poor-grade mica. For example: one deposit may have a little mica that will run II per cent good stain and better when trimmed and contain 2 kg. of crude mica per cubic meter of pegmatite, while another may run 0.2 per cent of good stain and better, and have a mica content of 10 kg. per cubic meter. A number of stripping projects were found in the vicinity of Raul Soares, Minas Gerais. These were sampled in the various old workings by cutting out a cubic meter of pegmatite and saving the usable mica. Because of the proximity to the surface of most stripping projects, about 34 per cent only of the mica is good for trimming. The other 66 per cent is too badly weathered to be of use. In Table I are given data collected on five properties near Raul Soares. In Table I, "value per cubic meter of pegmatite" means the value of the qualified mica obtainable. This does not include the half trimmed and splittings. By "value per cubic meter of matter" is meant the value of the qualified mica per cubic meter of material excavated; i.e. both waste and pegmatite. This is the figure that should he used to determine whether the operation will be profitable or not, as the cost of stripping is about $0.I4 per cubic meter. With new machinery not subject to breakdowns, the cost per cubic meter should be around $0.10 to $0.I5. To this should be

Jan 1, 1946

By F. H. Wilson, E. W. Palmer

G. L. Bailey (British Non-Ferrous Metals Research Association, London, England)—I was glad to see this further work on the structure and properties of the Cu-Ni-Fe alloys of low nickel content in which we have been so interested in the United Kingdom since before the war." The authors' data on the variation in solubility of iron in both 5 and 10 pct Ni alloys with temperature is based on more detailed observations than we have made but is generally in line with our own work. The difficulty in these matters is in the identification of the structures obtained. The precipitation of the second phase which we presume to be the a' solid solution, richer in nickel and iron, from the a solution with which it is in equilibrium occurs in such a fine state of division that its resolution by ordinary micro-graphic methods is impossible in the early stages. We have published some electron micrographs which illustrate the effects observed more clearly but we agree with the authors when they say that dark staining characteristics when the alloys are subjected to sea-water corrosion are more sensitive in detecting the presence of the a' phase than is the microscope. After taking this point into consideration, however, I confess to some difficulty in understanding Fig. 4. I can only assume that the precipitates visible at such a low magnification as 150 diam in these relatively coarse forms are produced from iron-rich areas of the initial solid solution due to inadequate homogenization. If this is so I find it difficult to accept the authors' contention that such local variations in iron concentration as are capable of giving the heavy precipitates shown in Fig. 4 do not in fact materially affect the solvus surfaces of their equilibrium diagrams. I share the authors' enthusiasm about the resistance to corrosion of these alloys by seawater but I am not fully in agreement with them on the vexing question of the best iron content for these alloys. In Fig. 3 of ref. 8, we give many results showing that the resistance of these alloys to impingement attack in the Jet Test increases as the iron content rises to 2 pct. With higher iron contents pitting at shielded areas is likely to occur. Admittedly the addition of 0.75 pct Fe produces a large improvement in corrosion resistance compared with a pure 90/10 Cu-Ni alloy, but the further improvement on raising the iron to 2 pct is substantial. We recommend from 1.5 to 2 pct Fe as the desirable range from the point of view of corrosion resistance. While it is true that British practice generally uses a hard tube, the corrosion resistance of the 10 pct Ni alloys has in our work been little affected by the structural condition. Although the annealed alloys blacken in seawater, this effect seems to be superficial and not to be accompanied by any real decrease in

Jan 1, 1953

By Thomas Donnelly

Introduction THE Province of San Cristobal is situated on the south side of the island of Santo Domingo about 25 miles west of Santo Domingo city, the capital of the republic. The copper mineralization is found about 1.-CAMP BUCARO. THE TOP OF THE RIDGE IN THE BACKGROUND MARKS THE CONTACT OF THE LIMESTONE AND TUFFS. S miles north of the town of San Cristobal, in the section known as Bucaro Hill; in San Francisco Hill; on the Nigua River; and on the Jaina (Liver. The district is reached by automobile from Santo Domingo city over an excellent road for 25 miles to San Cristobal, and then, by horse-back 6 or 8 miles up the Nigua River to what is locally known as "Camp

Jan 8, 1915

By E. P. Jennings

The abundance and value of the tellurium minerals of Colorado is well known, but, as yet, few analyses have been made of them, and I offer these as a small contribution to the chemistry of these valuable ores. 1. Native Tellurium.—The specimens from which the analyses of this mineral were made are from the " John Jay" Mine, Boulder County, Colorado, where it occurs in quite large masses, though mixed with more or less silica and iron pyrites. It is usually a finegrained, tin-white mineral, but sometimes occurs in distorted, hexagonal prisms in cavities in the quartz. Before the blowpipe it gives the reactions for tellurium, sulphur and iron; by cupellation, it yields a small amount of gold. An analysis of a coarsely crystallized specilnen gave the following results : Specific gravity, 5.10.5. Tellurium,.........68.40 Gold, :.........1.36 Iron pyrites,........24 92 Ferric oxide,.....4.37 Silica and silicates,........11.54 Silver, lead, and mercury,... traces. 100.59 Deducting the pyrites, iron oxide and silica, we have for the con]position of the mineral: Tellurium,..........97.78 Gold,.......... 2.27 100.00 Or, considering the gold to be in combination with tellurium to form sylvanite, we have : Nativc tellurium,........96.50 Sylvanite (An, Te3,),........4.50 100.00

Jan 1, 1879

By T. E. Watkins, M. D. Nelson

INTRODUCTION Deeper drilling for oil is becoming more and more the rule rather than the exception. With deeper drilling come additional problems, perhaps the greatest being those brought on by the higher temperatures encountered down the hole. particularly in the Gulf Coast region of Texas and Louisiana. Temperature gradients of the order of 1.8° to 2.0°F/100 ft are not unusual, and a gradient of 2.3"F.'100 ft is found in some areas of Texas. With a mean surface temperature of 74oF, the following temperatures could be expected for a geothermal gradient of 2.0°F; 100 ft: at 10,000 it. 271°F. 12,000 ft, 314°F: 14,000 ft, 354,oF; and 16.000 ft. 394°F. Severe gelation of lime-base drilling fluid in wells that have high bottom hole temperatures has become perhaps the most serious difficulty enconntered in drilling under such conditions. Lime-base drilling fluids have been very succesefully and widely used in the drilling of wells in the Gulf Coast region because of their inherent stability toward contaminants. their ability to suppress the swelling dispersion of bentonitic shales, and their ease of maintainance. The gradual recognition: during the past few years, that these muds were. in themselve. the cause of many difficulties experienced in drilling has led to wide-pread efforts by the drilling industry. to determine the reasons for the failure of these mud systems and to develop mud systems capable of performing satisfactorily under high-temperature conditios. MANIFESTATIONS OF HIGH-TEMPERATURE GELATION it is generally possible to recognize the symptons of high-temperature gelation early enough that advance predictions can be made of serious difficulties. in mud control, and the useful life of the drilling fluids can be extended by proper treatment. Following i.; a list of the manifestations of high-temperature gelation: (1) The drill string 'takes weight' while going in the hole after a trip. In early stages of high-temperature gelation it is possible to notice a slight reduction in drill string weight as the drill pipe is lowred near the bottom of the hole. (2) Excessive pump pressure is required to .tart the circulation of drilling fluid at or near the bottom of the hole when going hack to bottom after a trip. As the severity of the gelation increases it may be necessary to break circulation a number of times when going in the hole. (3) The drilling fluid from the bottom of the hole is thick and often granular or lumpy when pumped up after making a round trip. In a severely gelled drilling fluid system such a condition may be irreversible; that is, it cannot be stirred or chemically treated to produce a satisfactory drilling fluid. (4) Completion tool.. such as logging tools or perforating guns will not sink to the bottom of the hole. On some occasions completion tools will become stuck and require a fishing job to retrieve them if the wire line attached to them is broken. It is often difficult to determine whether the condition of the drilling fluid is responsible for sticking the tool or whether the wire line becomes key seated in a crooked hole and causes the allow difficulty. When there are 110 other symptoms of high-temperature gelation. then the difficulty may usually be attributed to the latter cause. (5) In extreme cases of high-temperature gelation it is necessary to "wash" and "ream" when going back to bottom after coming out of the hole. (6) In many -instance. it has been found to be extremely difficult and expensive to 1111 production packers 2nd tubing in moderately deep oil wells which had been drilled with a lime-base drilling fluid. In such instances-the original mud had apparently "set" to a consistency approaching that of a weak cement. CAUSES OF HIGH-TEMPERATURE GELATION Extensive test; have indicated that a lime-base mud does not develop a highly gelled condition at temperatures below 250°F. whereas above that temperature such condition often develops rapidly. (Fig. 1) concurrently. the following changes are evident ill the mud: (1) The alkalinity of the mud decreases to a very low value. with both caustic soda and lime being consumed. (2) The quartz content of the mud decreases sharply. (3) The bentonitic content of the mud decreases or di-appears, with concurrent decrease or loss of base exchange capacity of mud solids. (4) New compounds formed in the mud have been found to be cal-cium silicate, calcium aluminum silicate, and calcium sodium aluminum silicate. (5) The mud loses the ability to form a filter cake of low permeability. The above characteristics have been discussed, in part. by other authors

Jan 1, 1953

By H. W. Fleming, R. R. Brooks

The Clearwater Deposit, a small occurrence of massive-sulphide mineralization enclosed in an envelope of disseminated-sulphide mineralization, was discovered as a result of an aeroelectromagnetic survey in New Brunswick in 1955. Subsequently, additional flights were made over the deposit and various ground follow-up methods were employed to ascertain the nature of their response. All methods proved to be capable of indicating the occurrence with varying degrees of precision. This paper is a presentation and a discussion of the magnetic and electromagnetic data, both airborne and ground, and the self-potential data obtained over this deposit. The attention of Canadian mining exploration companies was initially focussed on New Brunswick by the discovery, in 1953, of the Brunswick ore body. Ground electromagnetic surveys were of considerable assistance in locating and developing this deposit. In the following year, 1954, the Heath Steele base-metal deposits were discovered by employing an airborne electromagnetic device and ground electromagnetic surveys to follow-up the airborne indications. These discoveries demonstrated clearly that both airborne and ground electromagnetic techniques were applicable for locating the near-surface deposits of massive sulphides present in this region. Airborne electromagnetic equipment became available on a contract basis through Aeromagnetic Surveys Limited early in 1955 and was used extensively thereafter throughout a large portion of northern New Brunswick. It was as a result of one of these surveys with Aeromagnetic Surveys Limited equipment in the summer of 1955 that the Clearwater Deposit was detected. The airborne anomaly was located on the ground by means of an electromagnetic survey using a Swedish Slingram unit. During 1956, the region was investigated more thoroughly- in the hope that other sulphide bodies might be located. Airborne electromagnetic coverage was extended and the Clearwater Deposit itself was used as a testing ground for the various methods and types of equipment currently in use in New Brunswick. In this paper com prative data are presented for the airborne magnetic, airborne electromagnetic, ground magnetic and ground electromagnetic surveys over this deposit. The ground electromagnetic instruments used were the McPhar vertical-loop unit and the Slingram and Boliden horizontal-loop units. Self-potential surveys were carried out with a McPhar unit. From the geophysical point of view, all ground electrical methods employed indicated the presence and the extent of the massive-sulphide mineralization with a good degree of accuracy. The horizontal-loop methods however, defined the contacts more precisely as is to be expected when dealing with a flatly-dipping

Jan 1, 1961

By AIME AIME

The Institute Headquarters at Spokane was established at the Spokane Hotel, and included a Bureau of Information for the benefit and comfort of members and guests of the party during the time of the meeting. The first session, held Tuesday afternoon, Sept. 28, 1909, in the beautiful Convention Hall ,of Masonic Temple, was called to order by Mr. E. J. Roberts, Chairman of the Spokane Local Committee, who introduced Mr. J. C. Ralston, City Engineer, representing the Mayor of Spokane and the Spokane Chamber of Commerce. Mr. Ralston extended to the members and guests of the Institute a cordial welcome to the city of Spokane, substantially as follows:

Dec 1, 1909

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus become citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil. EXTENSIVE beds of a soft aluminiferous phosphate lie in the Bartow-Pembroke region of Florida. Although the extent of the deposit is unknown, it is thought that the equivalent of at least five million tons of material containing 25 pct P,Os exists on one large mine property alone, and soft phosphates similar in nature are known to occur elsewhere in the state. This aluminum phosphate, unlike fluorapatite, is rendered fairly soluble in neutral ammonium citrate solution merely by heating it at a temperature below 600 °C, a property made the basis of a process patent by the junior author.' The possibility of producing an available form of phosphorus from what has hitherto been a worthless natural phosphate prompted the Bureau of Plant Industry, Soils, and Agricultural Engineering to make a brief study of the Pembroke phos- phate during the war years with a view towards determining the optimal temperature for heat treatment and the reactions involved in the process. The results of this study supplemented by data and information furnished by the junior author are presented in this paper. Description of Natural Phosphate: The phosphate with admixed quartz sand and siliceous matter occurs as a low-grade (8 to 9 pct P2O5) clay-like material that can be beneficiated cheaply by making a water separation of the very fine material from the sand, floating off the fine material, settling the suspension to a thick slurry, and finally de-watering the slurry by vacuum filtration followed by drying. The product dried at 100 °C contains about 16 pct water and 25 pct P2O5, about 1/12 of which is citrate soluble. Partial analyses of representative samples of the crude ore and corresponding concentrate are given in table I. The concentrate is light yellow in color and even after being dried at 100°C sticks very noticeably to laboratory grinding and screening equipment. Under the microscope the ground material is predominantly light brown crystalline aggregates with index of refraction near 1.61. The principal phosphate mineral constituent was identified as pseudo-wavellite with admixed phosphosiderite.2 Pseudo-

Jan 1, 1951

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus become citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil. EXTENSIVE beds of a soft aluminiferous phosphate lie in the Bartow-Pembroke region of Florida. Although the extent of the deposit is unknown, it is thought that the equivalent of at least five million tons of material containing 25 pct P,Os exists on one large mine property alone, and soft phosphates similar in nature are known to occur elsewhere in the state. This aluminum phosphate, unlike fluorapatite, is rendered fairly soluble in neutral ammonium citrate solution merely by heating it at a temperature below 600 °C, a property made the basis of a process patent by the junior author.' The possibility of producing an available form of phosphorus from what has hitherto been a worthless natural phosphate prompted the Bureau of Plant Industry, Soils, and Agricultural Engineering to make a brief study of the Pembroke phos- phate during the war years with a view towards determining the optimal temperature for heat treatment and the reactions involved in the process. The results of this study supplemented by data and information furnished by the junior author are presented in this paper. Description of Natural Phosphate: The phosphate with admixed quartz sand and siliceous matter occurs as a low-grade (8 to 9 pct P2O5) clay-like material that can be beneficiated cheaply by making a water separation of the very fine material from the sand, floating off the fine material, settling the suspension to a thick slurry, and finally de-watering the slurry by vacuum filtration followed by drying. The product dried at 100 °C contains about 16 pct water and 25 pct P2O5, about 1/12 of which is citrate soluble. Partial analyses of representative samples of the crude ore and corresponding concentrate are given in table I. The concentrate is light yellow in color and even after being dried at 100°C sticks very noticeably to laboratory grinding and screening equipment. Under the microscope the ground material is predominantly light brown crystalline aggregates with index of refraction near 1.61. The principal phosphate mineral constituent was identified as pseudo-wavellite with admixed phosphosiderite.2 Pseudo-

Jan 1, 1951

THE discussion of this topic at the Open-hearth Conference at Detroit on Nov. 3, 1927, was opened by statements of the general principles involved, made by manufacturers of molds. Because of their general interest they are printed below. WILLIAM HAIL RAMAGE,* Hubbard, Ohio.-I did not come prepared to read a paper, thinking. the most I would be called upon to do would be to make a few, remarks by way of discussion. A number of our friends have pre-viously asked questions. similar to this which really does not permit a direct "yes" or "no" answer. If I may he pardoned for so doing, I believe it advisable to discuss rather what we consider the principal factors which in-fluence mold life. I think possibly a little undue weight has been given to the subject of the analysis of the metal. For the last eight years we have spent a lot of time, effort, and money investigating this very problem from a chemical, physical and microscopic standpoint. We have had the benefit of complete records and history of over 100,000 molds in service at a variety of plants and over long periods of time. Obviously, I cannot be so specific that I should divulge information that is really a trade secret. In our opinion the principal factors influencing mold life are: (1) design of the mold; (2) process of manu-facture, including workmanship; (3) care in the steel plant or what might be termed "the use or abuse" in the steel plant; (4) the analysis of the iron and the physical con-dition of it. Under normal conditions these factors are of importance in the order named, although in specific cases they might be rearranged in any order you choose. For instance, the best mold made can be destroyed in one or two pours by subjecting it to certain conditions which are occasion-ally met in steel plant practice. Obviously, in that case, nothing else matters but that one item. On the other hand, I have seen molds made of such a terrible design that it was a foregone conclusion it would have to be broken after the second pour of the ingot to get it out. In that case, nothing but design mattered. As to the effect of process of manufacture, let me cite a case. Some years ago there were two batches of molds sent to a certain company. They were the same sized molds, used under the same conditions and in the same kind of service. There were, 20 molds in each batch. The second batch sent gave ten times the life of the first batch. It is true that the design was changed a little, but not very much, and it was not. a bad mold to begin with. It is possible that the iron may have been better in the second consignment but not very much. In my opinion, it is con-servative to say that of the 900 per cent improvement in life, 5 per cent was probably due to better iron, 25 per cent to better design and the remaining 870 per cent to process of manufacture and workmanship.

Jan 2, 1928

By N. F. Fiore, M. F. McGuire

THIS communication describes a series of experiments in which dislocation etch pitting was used to ascertain the depth of damage in crystals which were mechanically polished or which were cut with either a commercial metallographic cut-off wheel,* a com- All specimens were cut from single crystals of American Smelting and Refining Co. 99.999+ pct pure copper which were grown from the melt by the Bridge-man technique. The test specimens were disks, with faces being (111) planes and the disk axis a (111) direction. The disks were annealed in a vacuum of 10-5 Torr for 24 hr at 950°C prior to cutting or polishing and were given a light electropolishing in an ortho-phosphoric acid bath before etch pitting. Both Youngs1 and Livingston's2 reagents were used for etch pitting and the reagents gave identical quantitative results; however Livingston's reagent produced less staining and so all photomicrographs shown are of {111) surfaces etched with this solution. The surface of the annealed crystals showed well-defined subboundaries and a density of dislocations of about 1 X 106 per sq cm excluding those present in subboundaries, Fig. 1. The depth of cold work produced during mechanical polishing was determined after an annealed specimen was mounted in a paraffin holding block to protect it from extraneous damage. The exposed (111) surface was ground on metallographic papers and then polished on billiard cloth through 0.05-p alumina abrasive. It was necessary to remove about 0.3 mm (-0.01 in.) to obtain a structure representative of the annealed sur- face, indicating that the crystal was damaged to this depth during mechanical polishing. The cold work caused by standard cutting methods was measured in another series of tests in which cuts

Jan 1, 1967

By F. W. Clark

At the present time, when lixiviation versus amalgamation is being so thoroughly discussed by practical men, and published information is so meagre, the following tests, made by students in the mining laboratory of the Massachusetts Institute of Technology, may be of interest to others. The ore experimented upon was obtained from the Sombrerete mines near Zacatecas, Mexico. A careful analysis of the dried sample resulted as follows : Per cent. SiO2,............62.79 S.............13.86 Al2O3............4.39 Fe,............11.26 Zn,............1.57 CaO.............2.91 MgO,........... 0.06 Cu,.............0.12 Pb,.............0.40 Sb and As,..........trace CO2,............2.35 Ag,.............0.16 99.87

Jan 1, 1886

By Sir Robert Hadfield

SINCE the writer has been intimately connected with the development of manganese steel for many years, some remarks upon the early work with regard to the rolling and forging of this material might he of interest, and particularly as to the question of rails of special quality and of superior wearing qualities. In a paper on Iron Alloys, with Special Deference to Manganese Steel, read before this Institute at the International Engineering Congress in Chicago in 1893,1 the writer mentioned that, about 20 years ago, his firm in Sheffield produced railroad material, such as tires and axles, of forged and rolled manganese steel, thus showing that this product could be manipulated and worked up into the various required forms. The tires illustrated in the paper referred to above formed a particularly difficult class of work to produce in a special steel, but no special obstacles were met with Although there was no difficulty at that time in making and producing manganese steel in various forms, forged, rolled or pressed; nevertheless, on account of its higher expense, sufficient encouragement

Jan 2, 1914

September 1 to 6, 1918 COMMITTEE IN CHARGE Spencer Penrose, Chairman. George M. Taylor, Vice-Chairman. A. E. Carlton, Chairman. Finance Committee J. Dawson Hawkins, Secretary DENVER COLORADO SPRINGS CRIPPLE CREEK Finance Finance Thomas B. Crowe T. B. Stearns A. E. Canton , E. P. Arthur, Jr. Richard A. Parker Spencer Penrose N. S. Greensfelder T. B. Burbridge George M. Taylor A. E. Carlton. A. L. Blomfield, Treasurer B. F. Hill Arrangement I F. G. Willis Dave G. Miller Registration Norris E. Eads Frank Bulkley Loren C. Lennox 1V. E. Ryan Geo. E. Collins Horace F. Lunt Fred Jones .1. M. Tippett F. D. Smale Entertainment J. H. Haynes F. H. Bostwick Arrangement and Entertainment L. W. Lennox F. E. Shepard George M. Taylor A. L. Blomfield M. R.. Valentine Howland Bancroft J. D. Hawkins Thomas B. Crowe B. P. Morse A. E. Carlton E. P. Arthur J. G. Perry G. H. Clevenger Etienne A. Ritter Ladies Ladies , PUEBLO Mrs. T. B. Stearns, Mrs. C. M. Taylor, Mrs. C. H. Clevenger J. F. Welborn Chairman. Chairman H. B. Carpenter Mrs. C. Loughridge Mrs. S.-Penrose Mrs. A. E. Carlton L. B. Eames Mrs. H. Bancroft Mrs. J. D. Hawkins Mrs. A. L. Blomfield F. Robinson Mrs. G. Bancroft Mrs. L. C. Lennox Mrs. J. M. Tippett . Mrs. W. D. Leonard Mrs. H. F. Lunt -Mrs. E. C. van Diest Mrs. C. Chase Mrs. E. A. Ritter Mrs. AV. Strieby Mrs. F. H. Bostwick Mrs. L. S. Harner Mrs. C. L. Bailey Mrs. F. Bulkley Miss F. Dickerman Mrs. E. P. Shove Mrs. C. L. Tutt Mrs. F. C. Peck Mrs. F. D. Pastorius

Jan 10, 1918

By Nelson P. Hulst

COMMITTEES. DULUTH.-Nelson P. Hulst, Chairman; J. B. Adams, W. C. Agnew, M. H. Alworth, C. W. Andrews, R. Angst, William R. Appleby, C. E. Bailey, G. G. Barnum, E. F. Bradt, Mylie Bunnell, George L. Cheesebrough, Peter Christen¬sen, F. A. Cokefair, T. F. Cole, C. A. Congdon, N. Cowling, George H. Crosby, M. D. Cullum, C. d'Autremont, Jr., H. L. Dresser, C. T. Fairbairn. Walter Fitch, F. L. Gilbert, J. T. Hale, G. G. Hartley, E. B. Hawkins, M. S. Hawkins, J. H. Hearding, Louis Hill, L. J. Hopkins, F. E. House, J. C. Hunter, 0. D. Kinney, J. W. Kreitter, E. J. Longyear, Alexander McDougal, W. A. McGonagle, A. M. Marshall, W. N. Merriam, T. D. Merrill, John Millan, P. Mitchell, Clarence Moore, Hon. Page Morris, C. H. Munger, Henry Nolte, W. J. Olcott, A. L. Ordean, Thomas Owens, F. A. Patrick, H. M. Peyton; D. M. Philbin, Capt. Charles Potter (U. S. A.), L. W. Powell, Harry Roberts, Louis Rouchleau, George A. St. Clair, J. U. Sebenius, Joseph Sellwood, Amos Shepherd, W. B. Silvey, George Spencer, George C. Stone, H. B. Sturtevant, George D. Swift, Kirby Thomas, C. D. Thompson, A. D. Thomson, G. A. Tomlinson, Charles Trezona, R. R. Trezona, Maj. J. H. Upham, Charles Van Barneveld, W. W. Walker, J. L. Washburn, A. C. Weirs, H. J. Wessinger, A. B. Wolvin, Dwight E. Woodbridge. HOUGHTON.-W. E. Parnall, Chairman; W. D. Calverley, Secretary; W. B. Anderson, L. S. Austin, Jacob Baer, William Bath, F. J. Bawden., Simon Beahan, John Been, C. H. Benedict, Walter Bloomfield, S. H. Brady, Samuel Brady, Henry Brett, A. L. Burgan, F. I. Cairns, W. H. Cake, Arthur L. Carnahan, William Carpenter, Phillip Carroll, John J. Case, T. L. Chadbourne, W. A. Childs, B. F. Chynoweth, Captain James Chynoweth, H. P. Clausen, F. G. Coggin, H. D. Conant, J. B. Cooper, J. R. Cooper, John Cuddihy, Thomas Cummings, Robert Davidson, J. B. Dee, J. R. Dee, T. S. Dee, Theodore Dengler, M. M. Dennis, Captain Thomas Dennis,. F. W. Denton, A. D. Edwards, R. M. Edwards, C. S. Fales, Daniel Fisher, Henry Fisher, James Fisher, A. L. Floeter, Frank H. Getchell, M. C. Getchell, W. M. Gibson, W. M. Gilliland, James G. Glanville, George Goodale, H. S. Goodell, A. R. Gray, Edward Grierson, Homer Guck, H. D. Haddock, Captain Josiah Hall, John L. Harris, Captain S. B. Har¬ris, Enos Harrold, F. William Hartmann, George L. Heath, C. M. Hoar, Thomas Hoatson, 0. P. Hood, Captain Thomas Hooper, Captain Joshua D. Husking, Dr. L. L. Hubbard, Arno Jaelinig, E. D. Johnson, G. A. Koenig, Edward Koepel, C. H. Krause, R. H. Leach, A. W. Leonard, James MacNaughton, Edward McCormick, Thomas McDonald, R. T. McKeever, F. W. McNair, James McRae, John Mackey, John C. Mann, Major G. A. Marr, Captain Thomas Maslin, Harry Mercer, James Merton, Michael Messner, William F. Miller, Captain J. Milligan, Dr. J. W. Moore, Charles H. Moss, H. F. Nickerson, Charles L. Noetzel, P. H. Paine, John Penrose, Captain John Pentecost, Graham Pope, R. C. Pryor, James Ramsay, J. T. Reeder, Allen F. Rees, J. H. Rice, W. G. Rice, James

Jan 1, 1905