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By A. A. Smith, J. S. Smart

NUMEROUS investigations of the effects of the various impurities common to commercial coppers have been published, and the data have found wide use in industry. Naturally, emphasis has been placed on the oxygen-bearing coppers of the tough-pitch variety, but need is now evident for data covering the oxygen-free condition as well. Furthermore, relatively few of the important reactions between oxygen and the various impurities are well understood, and often the data at hand are not applicable to the low concentrations encountered in commercial coppers. This paper presents the changes in conductivity and softening temperature derived from individual additions of the group VIII triad, iron, cobalt and nickel, to high-purity copper, and constitutes a portion of the copper-research program being conducted at the Central Research Laboratory of the American Smelting and Refining Co. The method of preparation of high-purity copper and its alloys in either the oxygen-free or oxygen-bearing form has been described previously.1 The purity of this material, and the methods developed to produce it, provide the means for direct investigation of the very low concentration range in which the various impurities generally exist in commercial coppers. The usual necessity for extrapolation to this range using the results obtained from higher concentrations, and the interfering effects of extraneous impurities, are thus simultaneously circumvented. Since previously published data have adequately presented the effects of higher concentrations of iron, cobalt and nickel, the present investigation has been confined to the composition range 0 to 0.05 per cent. All alloys were initially prepared in the form of oxygen-free continuous cast rod, the weighed alloying additions in suitable form being charged with the pure copper to the continuous casting crucible. The best of the available high-purity alloying materials were used, and spectrographic analyses confirmed the absence of interfering elements from the alloys formed. Each series was compounded in the direction of increasing concentration, starting with pure copper in a new crucible and finishing with the 0.05 per cent alloy. Composition was closely controlled by adding the alloying element in the form of a carefully compounded and analyzed master alloy rendered uniform by continuous casting. The accuracy of this method of synthesis was proved by chemical analysis of the more concentrated alloys, and, accordingly, there is every reason to credit the stated composition of the very dilute alloys in the range where chemical analysis becomes highly uncertain. Oxygen-free samples for measurements of conductivity and softening temperature were obtained by drawing the continuous cast rod to wire of 0.081-in. diameter, employing a number of intermediate anneals to refine the grain structure. The

Jan 1, 1942

By A. J. Miles, A. D. Topping

in this paper, the theory of elasticity has been applied to the rock about a deep well, It is assumed that the rock has a modulus of . elasticity and a Poisson's ratio and that the theory of elasticity applies. It is necessary to know or assume the state of stress existing in the rock before it is penetrated by the well drill. The application of this theory indicates that stress concentration of shear, tensions, and compressions about the bore hole are of a high order. This is particularly true when a horizontal compressive stress exists in one direction only in the formation before drilling. If such an initial state of stress exists before drilling, then the rock will have stress concentrations of both tension and compression at the same elevation and of such magnitude that failure of the rock is likely. Accompanying these is a shearing stress of large proportion which is likely to produce spalling of the well walls. Internal pressure applied to the well bore will relieve the extreme compression but not the tension and has little effect upon the shear. Plastic deformation of the rock through a geological time tends to mitigate the stress concentrations. IntroductioN It has long been known that the stresses about holes and re-entrant corners of elastic solids under the influence of loads are different and generally more intense than those imposed upon the body else- where. Stress concentration at a re-entrant corner can be reduced by increasing the radius of the fillet at the corner. Stress concentration at the end of a crack in a plate undergoing either tension or compression Can be relieved appreciably by drilling a hole at the very end of the crack. Also, stresses can be increased in an elastic body in tension or compression by making a hole in it. The stress concentration is greatest at the edge of the hole. Considerable knowledge of the stresses which exist about the bore hole of a deep well may be had by applying our knowledge of engineering mechanics; or more particularly the theory of elasticity. It is, of course, necessary to make the assumption that the rock is elastic and behaves as an elastic solid, that is, that it obeys Hooke's law, has a modulus of elasticity, and a Poisson's ratio. It is also necessary to know, Or assume, the state of stress which exists in the rock prior to the penetration of the drill. With this knowledge it is possible to compute the stresses about the bore hole. The problem can be simplified by considering several simple cases separately and then by applying the principle of superposition to solve the more complex cases which are made up of the simpler ones. Case i—Rock Strata in Compression Penetrated by a Hole This case was first worked out by G. Kirsch* for structural material, but applies equally well to a horizontal rock strata in a state of in in one direction

Jan 1, 1949

By C. D. Rugen

GROUND raw material as fed to the cement kiln generally is a mixture of two to four components, each of which may have widely varying physical and grindability characteristics. Chemically similar materials found in the same or different deposits may also differ appreciably in physical properties, depending on their crystalline structure. The calcareous or principal cement raw material may vary from a soft chalky limestone or friable cement rock at one plant to a hard limestone or oyster shell at another plant. Argillaceous materials include clays, shales and granulated slag. Siliceous and/or iron-bearing material, including sand, iron ore and cinders, may also be required in addition for certain types of mixes. Frequently differences in grindability characteristics are not given the attention they deserve in comparing grinding results at one plant with those at another or in selecting suitable circuits or equipment. Many types of crushing and grinding units are used, with numerous open and closed circuit arrangements. Both wet and dry processes are used successfully. When rebuilding or installing a new grinding department, the choice of process or circuit in some cases may be dictated by the nature of the materials being ground but in other cases it may be the result of good salesmanship or a compromise. An over-all evaluation of wet process vs. dry process grinding should not be made without considering the effects on all other producing departments in the plant. In general, the more recent grinding installations, both wet and dry, have employed closed circuits, but many older open circuits are still in successful operation. In our experience, closed-circuit raw grinding pays, because of lower power consumption and less operating labor per ton of product. However, some dry open-circuit mills with improved equipment and operating methods compare favorably in performance with dry closed-circuit units. CHARACTER OF GROUND RAW MIX (KILN FEED) Grinding in the cement plant in general requires a considerably finer product than in most ore-grinding operations. A distinction between fineness of kiln feed and of cement may be made in that kiln feed preferably should be ground to a limiting size, whereas finished cement should include a range of size fractions including sufficient fine flours to give a product with satisfactory physical qualities. Grinding raw mix for kiln feed therefore is more comparable to ore grinding, although the limiting size is smaller. Most kiln feeds are ground from 85 to 95 per cent passing 200-mesh, depending on mix composition. Some cement chemists believe that raw materials cannot be too fine, since finer particles theoretically combine more readily and intimately in the kiln. However, there are certain definite practical objections to extremely fine kiln feed, such as loss of kiln dust, unstable material flow through the kiln and greater difficulty in control of chemical composition due to dust loss, and the disproportion of fines from the more easily ground component. Our

Jan 1, 1945

By H. H. Evinger, M. Muskat

A method has been developed whereby one may calculate the productivity factors of producing formations from a knowledge of the reservoir conditions. Account is taken not only of the heterogeneous character of the gas-oil flow system but also of the detailed variations with pressure of the shrinkage and viscosity of the oil, the solubility of the gas in the oil, and even the variability of the gas viscosity and the deviation of the gas from ideal behavior. Curves are shown giving the results of numerical calculations on the production rate as a function of the pressure differential for a high-prcssure and a low-pressure system, three values of gas-oil ratio being treated in each case. Curves are also given showing the variation with distance from the well of the pressure, oil saturation, and permeability. The effect of connate water is briefly discussed in relation to the apparently large discrepancies between the calculated and observed productivity-factor values. Introduction The significance of the productivity factor as a measure of the capacity of an oil-bearing formation to produce is well recognized; for it is the composite and integrated resultant of the physical prop-crties of both the porous medium and the fluid stream passing through it with respect to the ease with which the particular petroleum fluids present in the formation can flow through it and into producing wells. The most direct method of determining the productivity factor of a well consists, as is well known, in the simultaneous measurement of reservoir-pressure differentials and rates of production and the expression of the data in terms of rate of flow per unit pressure drop.' Actual measurements carried out in this manner on producing wells have given factors that generally lie in the range of o to Ioo bbl. per day per pound pressure drop. This wide range arises not only from variations in permeability but also from the varying sand thickness of producing formations. One of the aims of developing a theory of the mechanics of oil production obviously is that of predicting what the productivity factor should be from a knowledge of the individual characteristics of the producing formation and the fluids produced. For homogeneous fluid systems passing through a porous medium into a producing well, it has been known for some time that the steady-state rate of liquid flow Q is given by the formula:* Q ? u log r?/r? where k is the sand permeability, h its thickness, µ the liquid viscosity, ?p the pressure drop between the well and the distant parts of the reservoir, in particular that at a radius re, and r? is the well radius. This gives the productivity factor: f= Q/kh?p ? 2p/µ log re/r? f=Q/ kh?p ? 2p/µ log re/r? which will have a numerical value for a

Jan 1, 1942

By M. Muskat, H. H. Evinger

A method has been developed whereby one may calculate the productivity factors of producing formations from a knowledge of the reservoir conditions. Account is taken not only of the heterogeneous character of the gas-oil flow system but also of the detailed variations with pressure of the shrinkage and viscosity of the oil, the solubility of the gas in the oil, and even the variability of the gas viscosity and the deviation of the gas from ideal behavior. Curves are shown giving the results of numerical calculations on the production rate as a function of the pressure differential for a high-prcssure and a low-pressure system, three values of gas-oil ratio being treated in each case. Curves are also given showing the variation with distance from the well of the pressure, oil saturation, and permeability. The effect of connate water is briefly discussed in relation to the apparently large discrepancies between the calculated and observed productivity-factor values. Introduction The significance of the productivity factor as a measure of the capacity of an oil-bearing formation to produce is well recognized; for it is the composite and integrated resultant of the physical prop-crties of both the porous medium and the fluid stream passing through it with respect to the ease with which the particular petroleum fluids present in the formation can flow through it and into producing wells. The most direct method of determining the productivity factor of a well consists, as is well known, in the simultaneous measurement of reservoir-pressure differentials and rates of production and the expression of the data in terms of rate of flow per unit pressure drop.' Actual measurements carried out in this manner on producing wells have given factors that generally lie in the range of o to Ioo bbl. per day per pound pressure drop. This wide range arises not only from variations in permeability but also from the varying sand thickness of producing formations. One of the aims of developing a theory of the mechanics of oil production obviously is that of predicting what the productivity factor should be from a knowledge of the individual characteristics of the producing formation and the fluids produced. For homogeneous fluid systems passing through a porous medium into a producing well, it has been known for some time that the steady-state rate of liquid flow Q is given by the formula:* Q ? u log r?/r? where k is the sand permeability, h its thickness, µ the liquid viscosity, ?p the pressure drop between the well and the distant parts of the reservoir, in particular that at a radius re, and r? is the well radius. This gives the productivity factor: f= Q/kh?p ? 2p/µ log re/r? f=Q/ kh?p ? 2p/µ log re/r? which will have a numerical value for a

Jan 1, 1942

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

By T. E. SCHTVARZ

THE publication of the report by Mr. F. L. Ransome was welcomed by many engineers who had mined in the heart of the Sail Juan country, braved its long and snowy winters, climbed its lofty peaks, run the gauntlet of its snow-slides, and studied its problems of geology, while making dividends for their English or American clients. This report helps one to understand why the bonanzas occurred, and why the inevitable borrasca presents itself where least expected. The Red Mountain district of Ouray county, a very productive section from 1884 to 1893, occupies considerable space in the report mentioned.. The character of the ore-occurrence, being distinctive and presenting many features not existing elsewhere, has been deserving of special study. It is to be regretted that Mr. Ransome was .unable to observe the conditions underground, as all the principal properties, many of which I opened and developed, were closed at the time of his investigation: It has been my privilege to have contributed a few brief papers recording my observations in developing these properties ; and it is the object of the present paper to present certain sections of the Yankee Girl mine, which throw additional light on the geology of the section and make the available data more complete. The main Yankee Girl chimney or " stock" was the most productive for the first 500 ft. in depth of any chimney in the district.

Mar 1, 1905

By P. P. Reichert, L. S. Gournay, N. T. Burdine

An investigation of equivalent pore entry radii in typical samples of petroleum reservoir rock and the pore volume associated with each value of pore entry radius has been made. Theoretical discussions together with experimental procedures for obtaining pore entry radii and the distribution of pore volume with pore entry radii are presented. Experimental results on a number of core samples, along with typical distribution curves, are shown. Data on the per cent of the pore volume filled by mercury at a pressure of 1500 psi are included. The results of re-runs of samples, made possible by regenerative apparatus, show the repeatability of the data and indicate the amount of physical change in the samples by mercury penetration. Theoretical equations for calculating permeability from pore size distribution data were derived and the results of such calculations are compared with measured gas permeability data. The effect of the shape, surface area, and weight of the sample on the pore size distribution of reservoir rocks was investigated experimentally. Mercury capillary pressure curves are compared with those obtained by the porous diaphragm method using pas to displace water. Standard core analysis techniques, in general, lead to quantities which are statistical averages of the varying properties of the samples under examination. Although such statistical information has real value in predicting the gross performance of porous bodies. it fails to provide fundamental information concerning the properties of the porous medium itself or any processes which may be occurring in it. For example, a gas permeability measurement on a core sample is an indirect way of determining an average pore radius for that particular sample. Since there are many combinations of pore radii that will give the same radius. and, hence, the same permeability, no information is obtained on the pore size distribution. Furthermore, similar values in permeability do not imply similarity in other properties of a porous medium. For instance, it is possible to have two core samples with identical permeability which would have different residual oil contents at the end of an air-oil drive, or even different amounts of interstitial water. It has been recognized for some time by the petroleum industry that a determination of pore size distribution for porous reservoir rocks offered promise of increased understanding of fundamental flow processes in the porous matrix. and therefore of petroleum res- ervoir performance in general. There have recently been published several methods for determination of pore size distribution in porous materials. A report is given here of the modifications in equipment and technique required to adapt one of these methods to measurements on petroleum reservoir core samples. Although only a few correlations or applications of the method are available for presentation at this time, the technique is brought to the attention of the industry so that the opinions and experience of others with this or similar techniques may be exchanged. It seems possible that the method will have wide application in the future. METHOD There are three general methods which may be employed to measure the pore size distribution in naturally occurring rock formations. One method1 is based on experimentally determined adsorption isotherms for calculating the surface area of the porous medium. Knowing the surface area and the pore volume, a rough estimate of the pore radius can be made. Since this method depends on the thickness and uniformity of the adsorbed layer, the validity of the results would be highly questionable. A second method utilizes capillary pressure data obtained by static dis-

Jan 1, 1950

By Brown, R. W., G. H. Neill, R. G. Loper

All facets of ball sealer behavior must be known and understood to design for their optimum use in well treatments. The down-hole factors including the inertial forces, drag forces and holding forces have been discussed. Equations have been developed and presented for these forces. The use of these equations in this process will contribute to the most efficient use of an economical and proven ball sealer process. The urocedure presented has been used to successfully analyze field results indicating problems involving the use of ball sealers. These problems have been isolated and corrected in future treatments by using the procedure presented to revise the perforating program, the injection rate, the design of ball sealer stages and/or the type and size of ball sealers. The procedure presented also indicates that dislodgement of ball sealers occurs primarily in ultra slim-hole completions. INTRODUCTION The perforation sealing process has been proven highly successful and economical since it was introduced to the oil and gas industry in early 1956.' Since it has proved so successful in multistage fracture treatments at a much lower cost than conventional packers, the ball sealer process has become a byword in well completions.' Not only has it changed the design of fracture treatments, it has changed the concepts of selectively perforating and has greatly aided the success of the single-point and limited-entry techniques." Yet with all the advantages, there are still facets of ball sealer behavior that are not widely recognized. These must be known and understood to better design and execute the optimum ball sealer treatment. The down-hole behavior of ball sealers is influenced by a number of factors including an "inertial force", a "drag force" and a "holding force". These are considered in two phases—the initial seating of the ball and the forces tending to unseat the ball after contact has been made (see Fig. 1). This paper presents a theoretical study of these factors and formulas for predicting their influence. The authors acknowledge the fact that the flow equations presented herein describe the behavior of Newtonian fluids and do not cover the so-called power-law fluids. The assumptions made, however, are reasonable and well within practical limitations of the conditions encountered during field application. For example, it is assumed that the perforations are round with a discharge coefficient of 0.82. While this may not be exactly true, it has been verified within practical field limitations.' The discharge coefficient would not vary significantly even if the perforation size or configuration varied pronouncedly. The approach of assuming uniform perforation size is not as strained as it might first appear. Normally, a perforator contains charges equally spaced with the same number in each vertical (or horizontal) plane. If the perforating gun is not centralized, the holes in one plane will be smaller than average, while the holes in opposing planes will tend to be larger than average. The net result is that the two effects tend to balance. FACTORS AFFECTING CONTACT WITH PERFORATlON Ball sealers are injected into well treating fluids for the purpose of contacting and sealing those perforations which are accepting the fluid flow. The efficiency of the sealers is primarily influenced by: (1) the velocity of the balls down the pipe, and (2) the fluid velocity through the perforations. To divert the sealer to the perforation, the inertial force of the ball must be overcome by the drag force created by the fluid velocity through the perforation. BALL VELOCITY The final, or stable, velocity of the ball is the sum of the actual fall velocity and the fluid velocity. This will be

By John E. Carr

A bewildering variety of continuous thickeners and clarifiers are used in mineral industries and other heavy industries. General topes arc: ? Conventional thickeners ? Thickeners with flocculating feedwells ? Solids contactors ? Tray thickeners ? Lamellas ? Conventional thickeners with Lamellas ? High flow, fluid bed thickeners These units must be adapted to varied applications. They must provide operating flexibility to meet process needs. Such factors multiply the decisions which must be made prior to the selection of a thickener. The seven types of thickeners listed above, with their variations, share design concepts which limit their application and which can be used to evaluate their performance. Some of these arc: ? Feed velocities must be limited and/or controlled. ? Natural or reagent flocculation is necessary. ? Horizontal settling area is the basis for capacity. ? Overflow velocities must be limited and. or controlled. ? A controlled underflow is necessary. Thickener selection is the application of these needs to the basic process concepts. The basic function of a thickener, in the minerals industry, is the separation of a thickener sludge containing fine solids from water. In addition to this primary separation function, others include: ? Separation of solids from water ? Separation of flocculated solids from slimes ? Storage of solids ? Control of percent solids ? Storage of water ? Process control by absorbing fluctuations in feed ? Process control by increase in head clue to the depth and percent solids of the thickened sludge. Most thickener designs, suitable to minerals applications, are based on the separation of minus 65-mesh, 2.7 specific gravity solids containing slimes. These designs are routinely adapted to coarse and or denser materials. Materials of lower specific gravity such as coal, wood, char, some chemical precipitates and organics act Hike slimes if a thickener is used. Perhaps the most conservative approach to sizing and application is the use of comparative data from similar plants or similar industries. Thickeners are-routinely used in a great number of industries from which there is good historical information available. In the minerals industry, thickeners are used in: clay sizing, coal refuse, heavy media, copper concentrates, copper tailings, gold flotation concentrates, and countercurrent decantation for cyanidization in gold and CCD in uranium. Concentrate and tailings thickeners are used in iron ore plants, and concentrate and tailings units in lead-zinc plants. In addition, there arc thickeners designed to handle lime mud; limestone concentrates and tailings; phosphoric acid; potash; and rutile concentrates. Thickeners are, in addition, widely used in gravel plants for water reclamation. This gives excellent data on clay settling in some cases. Thickeners are used extensively for slurries generated by flue dust from wet scrubbers. Thickeners in flue dust applications are operating with considerable variations, treating blast furnace dust. BOF flue dust, and wood char. Similar applications are met in the power industry with fly ash and SO2 scrubber systems. Even though field data is preferred, such data has limitations as listed: ? Flowsheets are seldom identical. ? Data is often incomplete or limited. ? Ores vary significantly. ? Operating needs are changing. For these reasons, mathematical and theoretical methods are needed for application of field data to a specific project. In addition, laboratory data for similar projects and, if possible, laboratory data on a representative sample should be used to specify the thickener. There is a great volume of thickener literature. The references for this paper, along with their references, and past AIME papers provide excellent background. Older literature can be reviewed in light of current methods. It is interesting to note that the requirements for higher flow rate designs, more extreme flocculation systems, etc., can be logically introduced by reading Gaudin's Sections on Flocculation and Thickening, which was written before field installations could illustrate all of his ideas. The problem, then, is to select hardware which will take into consideration the functions of flocculation, separation of the solids, water clarity, control of the underflow, and control of the overflow. Reliable operation and simple control are customary.

Jan 1, 1979

By Philip W. Simmons

THE Colorado Plateau uranium province is in a mining boom rivaling the most colorful days of the early West. The application of scientific skills and the use of modern and novel mechanical equipment, however, is unique. No metal has ever received such concentrated effort from geologists and mining engineers. Moreover, no other metal has had the variety of tools available for finding and mining ores. Radiation detection equipment, bull- dozers, truck-mounted wagon and core drills, jeeps, airplanes, helicopters, tractor loaders, self -propelled 3-wheeled dump cars, front-end loaders and fleets of modern trucks are some of the present-day tools of the uranium prospector and miner. Because uranium is so vital to our national defense, the Atomic Energy Commission has offered many incentives for its mining. Through a series of circulars, the AEC has established base price schedules and various incentive payments. The incentive payments for acceptable ores from domestic mines are: (1) a guaranteed base price of $3.50 per Ib for ores assaying 0.20 pct U3O8 and more; (2) premiums based on grades above 0.20 pct U3O8 as for example, ores assaying above 0.50 pct U3O8 receive $1.00 per lb premium; (3) a development allowance of 506 per Ib of U3O8 contained in ores assaying over 0.10 pct U3O8 (4) an ore haulage allowance of 64 a ton mile for a maximum of 100 miles; and (5) an initial production bonus which may amount to as much as $35,000 in addition to all other payments. The producers have been guaranteed this policy until Feb. 28, 1957. The other four will continue until April 1962.

Jan 4, 1954

By L. D. Jaffe

From the limited experimental data in the literature, preliminary values were derived for the thermal diffusivity of titanium alloys and for the quenching severity of various mediums used in heat treating them. The thermal diffusivity, under quenching conditions, was found to be approximately 0.006 sq in. per sec. The quenching severity H for brine is approximately 8, for water 4, for oil 0.9, for air 0.08, and for argon 0.02 in. -' The quenching severity of the Jominy-Boegehold end quench water jet against titanium alloys appeared effectively infinite. Using these results, graphs were prepared showing ideal round sizes and Jominy positions having cooled conditions equivalent to those at the center and surface of titanium alloy rounds, plates, and sheets quenched in various media. THE importance of proper quenching of steel parts has long been recognized, and much quantitative work has been done on the subject. Recently, it has become evident that for titanium alloys, too, the rate of cooling from high temperature is important in obtaining high strength and hardness. Maximum hardness and strength may not be attained in the as-quenched condition but rather after a subsequent tempering or aging treatment. Nevertheless, if cooling from temperatures near the ß transus is too slow, for the hardenability of the alloy used, a soft a-ß structure will be produced which will not harden on subsequent aging.'-" The quenching of parts of practical interest can usually be approximated by simple shapes, such as cylinders (rounds) and plates (or sheets) of various thickness and combinations of these. A standard that has been used extensively for comparison purposes is the center of an ideal round: a cylinder quenched in a medium that instantly cools its surface to room temperature." For steel, considerable practical use has been made of the Jominy-Boegehold end quench hardenability specimen,".' and its value for titanium alloys is becoming evident. It therefore appeared worthwhile to attempt comparison of cooling conditions in titanium alloy rounds and plates of various sizes quenched in various media with cooling conditions in ideal round and Jominy quenches. These comparisons are based upon measurements reported in the literature. Quenching Severity of Jominy Water Jet and of Brine As one starting point, there were available the data of Phillips and Tobin8 for positions on a Jominy specimen having the same hardness as the centers of round bars of various size quenched in 5 pct NaOH brine, shown in Table I. The Jominy speci- men is a round bar, normally 1 in. diam and 4 in. long, quenched by a water jet at one end and air cooled on the other surfaces.' After quenching, hardness is measured vs distance from the quenched end on longitudinal flats ground 0.015 to 0.10 in. deep. The data of Table I were based on a subsized specimen of 3/4 in. diam. Since the positions tested are close to the jet quenched end, cooling there may be taken as due solely to the jet, and air cooling can be neglected. These positions are then equivalent to various locations near one surface of an 8 in. plate jet quenched on both sides. Assuming that the thermal diffusivity is constant and that Newton's law of cooling holds, temperature vs time curves at corresponding positions in Jominy specimen and round bar then may be calculated for various assumed quenching severities of the water jet and of the brine. Cooling curves are generally taken to be metallurgically equivalent when they show the same time to reach a temperature halfway between the initial (heat treating) temperature and the final (quenching medium) temperature.5 On this basis, using Russell's tables,9 upplemented by heat flow tables derived in similar fashion by the author for positions near the surface of severely quenched plates, it was found that the experimentally observed equivalence, Table I, was best matched if the quenching severity H of the Jominy water jet was taken as infinite (H = co). This means that the jet quenched surface should be considered as instantly cooled to the temperature of the water

Jan 1, 1956

By Strathmore R. B. Cooke, Eugene L. Talbot

THE perfluoro acids and derivatives show unusual surface-active properties that qualify them as possible flotation reagents. They lower the surface tension of water from 15 to 20 dynes below that obtainable with the corresponding hydrocarbon compounds.1, 2 Fluorochemicals adsorb very strongly on solid surfaces to give films that exhibit larger contact angles than films of the corresponding hydrocarbons."' * The large contact angles probably result from the terminal —CF3 group. The perfluoro acids are made by electrolysis of the corresponding carboxylic acid in anhydrous hydrogen fluoride.5 From the perfluoro acids many derivatives may be obtained, such as amides, amines, alcohols, xanthates, ethers and esters and others. Since the fluorinated analogues of the conventional hydrocarbon flotation collectors possess enhanced surface properties, a few were selected for testing. Because a survey of all possible minerals and reagent combinations would be out of the question, hematite was chosen to represent a nonsulphide system and pyrite to represent a sulphide system. The fluorinated reagents used in these experiments were prepared in the research laboratories of Minnesota Mining & Mfg. Co. Some were synthesized especially for this research. They are not available cokmercially. Separation of Nonsulphide Ores: The separation of oxides from silica has always been a challenge to the flotation industry because differences in surface properties of the minerals are normally insufficient to produce clean concentrates. Oleic acid," rosin acids,' and amine salts% ave been used to considerable extent to effect separation of metal oxides and silica. The system hematite-silica was chosen to represent the nonsulphides both because of its difficulty of separation and because large tonnages of easily obtainable material are available, such as gravity concentration tailings and nonmagnetic taconites on the Mesabi Range. The wash-ore tailings used here contained approximately 35 pct iron after desliming. Samples of the material used in this work were part of the same lot used by Chang, Cooke, and Huch9 and were prepared in an identical manner. Reagents for Nonsulphide Ores: Since one of the purposes of this investigation was to compare hydrocarbons with fluorocarbons, reagents of known behavior such as oleic acid, and the alkali metal salts of certain resin acids (Dresinates), were established as standards. Hydrocarbons and fluorocarbons of comparable chain length and other experimental fluorocarbons were tried as collectors for hematite. A list of the materials used and the concentrations of their stock solutions are given in Table I. Since silica can be selectively floated from hematite by conventional reagents," a few fluorocarbon reagents were also tried for this purpose. Their composition and concentrations are given in Table 11. Most of these reagents served the dual function of collector and frother. In the case of F-11 flotation did not occur but it served as a frother when F-6 was employed as a collector. Reagent grade sulphuric acid and sodium hydroxide were used to regulate the pH. Deionized water containing less than 0.1 ppm of salts expressed as NaCl was used for all solutions and flotation tests. The pneumatic flotation cell consisted of a 350-ml fritted glass Buechner funnel with a source of filtered air which could be controlled by a needle valve." A 50-g sample of ore and 250 ml of deionized water were added to the flotation cell and stirred slowly. The reagents were added and the pulp was conditioned before air was admitted to the cell. Approximately 15 ml of the pulp were removed for pH determination before flotation was started and were then returned to the system. The pH was again measured after flotation. Air was admitted to the cell until no further flotation occurred or until the character of the float changed markedly. Both the float and the nonfloat products were filtered, dried, weighed. and assayed for iron. The cell was washed in hot water and rinsed with deionized water after each test. Occasionally the cell was cleaned with concentrated hydrochloric acid to remove iron oxide particles from the glass frit. Experimental Results: Above a pH of 8, sodium oleate was an effective collector for hematite. The emulsification of equal parts of heavy fuel oil (20"

Jan 1, 1956

By D. O. LIVINGTON

(Presented by invitation at a meeting of the Spokane Local Section of the institute, Feb. 17, 1912.) THE Pilares de Nacozari mine is located in Sonora, 75 miles south of Douglas, Ariz. The town of Douglas is on the International Boundary and is the place at which the ores from the Bisbee mines are smelted. The Moctezuma Copper Co. owns the mines at Nacozari, and the copper-concentrates shipped to the Copper Queen smelter, at Douglas, make a good smelting-mixture with the Bisbee ores. The Moctezuma Copper Co. and the Copper Queen smelter at Douglas, as well as the railroad from Douglas to Nacozari, are owned by the Phelps Dodge Co. The ore-deposit occurs in the form of a large ellipse with a major axis of approximately 2,000 ft. and a minor axis of about 600 ft., the major axis bearing about 90 W. of N. The whole of this ellipse is more or less mineralized; the surface being principally an iron gossan with some occasional copper-stains. Below the oxidized zone, which is not more than 50 ft. deep, the minerals are pyrite and chalcopyrite, with occasional seams of chalcocite, the latter being rare. There appears to be no well-marked zone of secondary enrichment, the oxidized gossan over the greater part of the deposit changing suddenly to what is apparently the original unaltered ore. The copper-values are concentrated around the perimeter of the ellipse, and it is principally around this perimeter that the mining is done. The ore mined averages a little more than 3 per cent. of copper, with a small amount of silver, less than an ounce per ton. Some ore of considerably higher grade than this has been shipped, however, but the above average is of the mill-run. The ore is wider near the two ends of the ellipse than along the sides, and is mined in some cases to a width exceeding 200 ft. The country-rock for the first vertical 500 ft is a volcanic acid breccia, probably rhyolitic; below

Sep 1, 1912

By P. C. J. Gallagher

A number of recmt determinations for the ratio of extrinsic to intrinsic stacking fault energy in fcc solid solutions are examined. Some of these arise from incomplete analyses which can yield only approxi?nate values for the ratio. Reliable results, on the other hand, obtained using extrinsic-intrinsic fault pairs, show that the extrinsic and intrinsic fault energies are essentially equal in several materials. There is some reason to believe that this finding is of general applicability to fcc elements and alloys. A wide range of values has been obtained for the relative magnitudes of the extrinsic and intrinsic stacking fault energies (yext and yint, respectively) in recently published studies in a variety of materials. In contrast, Hirth and Lothe' using a central force model have shown that out to tenth nearest-neighbor interactions the perturbation in energy caused by both types of fault is the same. Although the model used is not completely valid in metals, there is nevertheless some indication that marked variations of yext/nnt should not be observed from one material to another. In early work in Cu-A1, Cu-Ge, Ni-Co, and stainless steel all the deformation faults observed in the electron microscope were found to be intrinsic in nature, which led to an attitude that the extrinsic fault energy must be considerably greater than the intrinsic. Extrinsic faulting arising from deformation has, however, more recently been directly observed in Au-4.8 at. pct n;~ Ag-6 at. pct Sn and Ag-8 at. pct sn; Ag-7.5 at. pct In and Ag-11.8 at. pct 1n;"' pure silwer and Ag-0.5 at. pct ~n;' and Cu-22 at. pct Zn, Cu-30 at. pct Zn, and Cu-7.5 at. pct ~1.l' Multilayer loops containing extrinsic faulting have also been observed in quenched aluminum." While peak asymmetries in X-ray faulting probability studies were generally attributed to the presence of twins,Lelel2 has recently reinterpreted earlier X-ray data in Ag-Sb alloysU in terms of the presence of extrinsic faulting. The determinations of yeXt/yint made from the above studies are shown in Table I, with a brief description of the techniques employed. A number of the methods utilized are deficient in one or more respects, and the reliability of the values listed will be discussed. ~ele'~ recognizes that his approximate determinations of yext/yint assumes equal numbers of extrin-sically and intrinsically faulted dislocations. It is well-known, however, that such an assumption is not at all justified since extrinsic faulting has but rarely been observed in samples studied in the electron microscope. The only conclusion that should be drawn from the X-ray results at present is that the total intrinsic scattering cross section (i.e., the product of the width of the intrinsically faulted dislocations with their density) is approximately ten times greater than for extrinsic faulting in these particular samples. An important point is that the relative magnitudes of the energies cannot be inferred from results of this type, unless the intrinsic and extrinsic faults form with equal ease. One must recognize that, although a formation barrier may restrict the amount of extrinsic faulting which occurs, this in no way implies that the extrinsic and intrinsic energies should be different. It is unlikely that a worthwhile estimate of the relative densities of extrinsically and intrinsically faulted dislocations can be made at the high deformations present in X-ray samples. ~oretto,'~ from a statistical argument applied to the nonobservation of extrinsically faulted tetrahedra out of a large sample, concluded that yeXt/yint could not be less than -4.5. However, the present author feels that a high-energy formation barrier as just supposed also explains this finding satisfactorily and that no conclusion can possibly be drawn concerning the actual extrinsic stacking fault energy. The same argument also serves to explain the fact that extrinsic faulting has been relatively little observed in the electron microscope. Extrinsic-intrinsic node pairs and isolated extrinsic nodes were first reported by Loretto~ and subsequently by Ives and Ruff,' Gallaher,' and Gallagher and Wash-burn.' Ives and Ruff' found a wide spread in the ratio of extrinsically to intrinsically faulted area in the node pairs they observed, and drew the very tentative conclusion that yeXt/yint 2 2. They recognized that a straightforward comparison of the size of the faulted areas could provide no more than a qualitative result without a theoretical analysis of the dislocation geometry associated with extrinsic faulting. A theoretical

Jan 1, 1969

By J. J. Gilman

Examination showed that characteristic cleavage step patterns are observed on the cleavage surfaces of undeformed, slipped, bent, twinned, compressed, and indented zinc crystals; and the effect of temperature is discussed. Dimples were seen to produce cleavage steps in a treelike pattern in otherwise undeformed crystals. The steps seem to originate when cracks intersect screw dislocations. IT has been known for a long time that the path of fracture in polycrystals may be discontinuous (see Jaffe, Reed, and Mannl for review). Recently, Kies, Sullivan, and Irwin2 have proposed, and given evidence, that crack propagation is discontinuous within individual crystals as well. Other evidence has been given by Low.' When discontinuous cracks within a crystal join together to make a macrocrack, the lamellae between each set of two cracks are torn somewhere, forming small cliffs. These cliffs appear as lines when the cleavage surface is observed microscopically.4,5 The lines have been called vein, tree, and riverlike markings by various authors, and they have sometimes been mistaken for fissures. The descriptive term cleavage steps is used in this paper. Cleavage steps vary in height over a wide range of values, from molecular dimensionsG to lor. and larger. Kies, Sullivan, and Irwin,2 as well as George,' have shown that the gross cleavage step patterns for plastics, polycrystalline metals, and for mono-crystals are sometimes similar. Thus, they depend mostly on the mechanical variables that prevail during cleavage and are relatively insensitive to the structure of the material. For example, parabolic markings2,7,8 sometimes result when cracks open up ahead of, and not coplanar with, the main crack front. If the advance crack has the same velocity as the main crack, their intersection line is a parabola, otherwise it is a hyperbola or an ellipse. The patterns are strongly affected by differences in crack velocities. This results in chevron patterns which point to the place of origin of the main crack. It is the purpose of this paper to demonstrate the existence of a mechanism of cleavage step formation which is a continuous rather than a discontinuous process. Also, certain characteristic step patterns are described, and the strong effect of temperature is shown. The specimens were zinc monocrystals (grown from 99.999+ pct pure metal). These were cleaved at room temperature and at — 196°C. Results and Discussion Cleavage step patterns are highly variable from point to point on a given specimen, as well as from one specimen to another. Although the patterns shown in the photographs are typical, they have been selected for graphic illustration. Figs. la and lb compare undeformed crystals that were cleaved at —196 °C and room temperature, respectively. Cleavage at room temperature (Fig. lb) resulted in a higher density of high steps (dark black lines) and enhanced the visibility of the fine background markings. Deformation by simple slip caused no marked change in the step patterns until the glide strain reached about 1.0. But, as Fig. lc shows, the density of high cleavage steps was greatly increased by large glide strains. Corrugations lying perpendicular to the slip direction may also be seen in Fig. lc. These are caused by deformation bands. The cleavage resistance of the crystal of Fig. lc was very high compared to undeformed crystals (estimated by the force on a needle required for cleavage). Striking and varied cleavage step patterns were observed on bent crystals. Two characteristic patterns that were observed on crystals bent at 25°C, and cleaved by reverse bending at —196°C, are shown in Figs. 2a and 2b. The first, Fig. 2a, consists of V-shaped lines similar to the parabolas of other materials2,7 Fig. 2b shows a pattern that is the equivalent of Fig. la, consisting of faint background lines with a few higher step markings. Cleavage of bent crystals at room temperature resulted in Figs. 2c and 2d. Now, the cleavage step lines show a strong tendency to follow one of two perpendicular paths. In Fig. 2c (bent once), many of the cleavage step components that lie parallel to the bend axis are assembled into irregular lines. In Fig. 2d (bent twice), the cleavage steps again tend to consist of two perpendicular components, but neither of the components is assembled into lines. Also, the step density is higher.

Jan 1, 1956

By John T. Ryan

DEFINITE improvement in its accident fatality rate in the coal-mining industry was recorded during 1941, based on preliminary figures for the period from January through October. Total production during this ten-month period was approximately 91 percent of the total production in all of 1940. The ten-month accident rate for both bituminous and anthracite mining in 1941 was 2.15 killed per million tons of coal mined, compared with a rate of 2.66 for the full year of 1940. The bituminous rate decreased from 2.55 in 1940 to 1.99 in ten months of 1941, and the anthracite rate from 3.62 to 3.53 in similar periods. The decrease is more apparent for the bituminous branch of the industry, as the high figure in 1940 was due to seven major disasters which brought death to 276 men. The same number of major explosions during ten months of 1941 caused only 64 lives to be lost. The severity of the explosions has been lower this year but a definite need still exists for reduction in this type of accident.

Jan 1, 1942

By J. F. Smith, J. E. Davison

The heat capacity of CaMg2 was measured over the temperature interval, 4.8° to 287°K, by the technique of low-temperature adiabatic calorimetry. Heat content measurements were performed with a drop calorimeter over the temperature interval, 273" to 673°K. From these data the thermodynamic functions, (FT - H0)/T, ST - So, and & - Ho, were evaluated. A third-Law calculation of the standard entropy of formation of CaMg2 yields a value of -0.25 * 0.06 cal per (°K g-atom) , and the free-energy function derived from this study when combined with existing equilibria data yields a value for the standard enthalpy of formation which is in agreement with direct calorimetric enthalpy measurements. The accompanying paper' shows that the enthalpy of formation of CaMg2 has been determined with good precision by three different calorimetric techniques.'-= TWO independent determinations of the Gibbs free energy of formation of CaMg2 have also been made; both determinations were based on vapor pressure measurements, being in one case hydrogen vapor pressures over ternary Ca-Mg-H alloys4 and in the other case magnesium vapor pressures over binary Ca-Mg alloys.5 The present determination of heat capacity of CaMg2 below room temperature and of the heat content of CaMg2 above room temperature was undertaken to provide supplementary data. These data are useful in their own right but can in addition be used to evaluate an entropy of formation for CaMg2 which, because of the interrelation of free energy, enthalpy, and entropy, can be used as a check of the self-consistency of the composite of the presently available information. LOW-TEMPERATURE HEAT CAPACITY The heat capacity of CaMg2 was measured over the temperature interval 4.87° to 286.64°K in an adiabatic calorimeter. The physical details of the calorimeter and the experimental procedure for measuring the heat capacity of a specimen have been adequately described by Gerstein et a1.6 The source and purity of the calcium and magnesium are described together with the methods of sample preparation and chemical analyses in the accompanying paper.' Results of chemical analyses of the material which was used in the present investigation are shown in Table I. These analyses show that, on the basis of the published phase diagram,7 the heat capacity sample contained a slight excess of a calcium while the heat content sample contained a slight excess of magnesium. However, in both cases the excess was small, and X-ray diffraction patterns showed reflections which were without exception attributable to CaMg2. The sample which was used for heat capacity measurements weighed 69 g while the sample container and addenda weighed 132 g. The sample was in the form of annealed powder, 50 to 60 mesh, and was sealed into the sample container under 0.1 atm of helium. Copper fins inside the sample container facilitated thermal equilibrium of the powdered Sample. Time intervals of the order of 10 min were required for thermal equilibration, and such times are normal for this calorimeter regardless of the form of the sample. The observed heat capacities were corrected for the small excess of a calcium through use of the heat capacity values tabulated by Hultgren et a1.8 The corrected heat capacities are tabulated as a function of temperature in Table II. The free-energy function and the absolute entropy of CaMg2, which were calculated from the experimental heat capacity data, are listed in Table 111. A smooth curve was fitted to a plot of the experimental values of the heat capacity and in only two instances above 30°K did the plotted points deviate from the curve by more than 0.2 pct. Below 10°K the deviation of several of the points was as much as 50 pct. These large percentage deviations were attributed to the small value of the heat capacity and to the low sensitivity of the platinum resistance thermometer in this temperature range. The deviations in the region of 10°to 30°K were less than 5 pct. Although the percentage deviations of some of the low-temperature measurements are large, the actual value of these deviations is small since the magnitude of the heat capacity in that temperature range is small. The error in the value of the third-law entropy at 298.15°K was estimated to be less than 0.01 cal per (°K g-atom). A value of -0.25 ±0.06 cal per (°K g-atom) was obtained for the standard entropy of formation at 298.15°K from the relation:

Jan 1, 1969

By Chester T. Sims

RECENTLY, a new type of superalloy material called TD Nickel* has been marketed.' It is a sim- ple, two-phased alloy, consisting of thoria particles dispersed in nickel of rather high purity (Ni-2 pct Thoz). Its mechanical properties appear relatively superior to previous experimental material attempting to use the oxide nonmetallic dispersion concept (except SAP), and superior to conventional nickel-base alloys at high homologous temperatures. This is derived from an interesting method of creating the dispersion, arising during chemical processing of the nickel and thorium salts in solution while reducing the nickel to metal. An evaluation of the thoria phase was conducted at this laboratory. Material and Procedure. TD Nickel was made available, consisting of several inches of 0.470-in. rod, extruded at a ratio of 64: 1, straightened, and centerless ground. Property determinations on this rod by the supplier at 1800°F showed an ultimate tensile strength of 11,400 psi, yield strength of 9600 psi, and 6 pct elongation. Specimens were removed from the rod for as-extruded metallography, and two 1/2-in. lengths supported on high-purity Al2O9 bricks were placed in a laboratory muffle furnace for exposure at 2000° F. The furnace door was left cracked to allow a slight amount of circulation. One specimen was removed at 200 hr for examination; the other was left for 2000 hr. Metallography. The micro structures obtained for the three conditions of exposure are shown in Fig. 1. Elongation of the grain structure in the extrusion direction is readily evident. The grains appear to be up to 0.001 in. (0.003 cm) long, with a length/width ratio of about 10: 1. Allowing for modest local in-homogeneities in structure, no significant change in thoria particle size or nickel alloy grain size occurred during the 2000°F exposure. However, etching depth varies slightly from one specimen to another, changing the number of particles visible. The thoria dispersion appears to be in the order of 0.01 (min) to 0.5 (max) p diam. The minimum diameter is difficult to estimate at X10,000, and may be less. Interparticle spacing appears to be about 0.1 p. Etching effects can be seen, depending upon grain orientation. A cubic etch-pit pattern appears in certain grains, apparently when etching is started by an anodic particle of thoria, Fig. l(c). The cubic pattern appears related to crystallographic orientation, and is prominent when the [ l00 ] direction is perpendicular to the plane of polish. The grains which present a ridged appearance in the photograph appear to be oriented with the [110} direction perpendicular to the plane of polish. Analysis. The thoria particle size was measured by a line intercept method perpendicular to the extrusion direction. Only particle sizes measuring 0.001 in. at X10,000 or larger could be extimated. Within limits of experimental error, particle size distribution appears to be unaffected by exposure, Fig. 2. To check structural stability further, a grain-growth evaluation was made. The number of grain-boundary intersections was counted at X500 on each of several traces normal to the extrusion direction for each condition. It can be seen from Table I that grain diameter appears unchanged by the 2000°F exposure. The slightly finer grain diameter after 200 hr may be attributed to variations in grain size from area to area in the original extrusion. From the present rather limited study of Ni-2 Th on, it appears that: 1) for time-temperature exposure up to 2000 hr at 2000°F (Larsen-Miller parameter = 57, homologous temperature = 0.8) thoria particles of the size studied are highly thermally stable; they do not significantly react, agglomerate, or diffuse; and

Jan 1, 1963

Mr. Tays (communication to the Secretary): Mr. Wynne's criticism of my paper* brings forward a few points which are really important, and might properly have been considered in the original paper. By calling attention to them he has rendered me a service. It is quite true, as Mr. Wynne says, that, in the tests reported by me, the Bryan mill was always working at a relative disadvantage, and my comparison of the work of this mill with that of the stamp-battery should be interpreted, therefore, so much the more favorably to the mill. Of course, wire screens can be used to advantage on the Bryan mill, if they are not of smaller size than 30-mesh; but

Jan 1, 1902