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PRESIDENT OF THE COUNCIL. JOHN HAYS HAMMOND NEW YORK, N. Y. (Term expires February, 1909 ) VICE-PRESIDENTS OF THE COUNCIL SAMUEL B. CHRISTY BERKELEY, CAL. JOHN A. CHURCH NEW YORK, N.Y. PERSIFOR FRAZER PHILADELPHIA, PA. (Term expires February, 1909 ) J. PARKE CHANNING NEW YORK, N. Y. FREDERICK W. DENTON PAINESDALE, MICH. JOHN B. FARISH New York, N. Y. (Term expires February, 1910)

Jan 1, 1910

By F. G. Tahmoush, N. J. Grant, E. P. Abrahamson

The effect of grain size on the brittle -ductile transition temperature of pure iron and three dilute Fe-W alloys has been investigated by slow bend tests. The brittle-ductile transition temperature for pure iron increased with increasing grain sizes from 8000 to 500 grains per sq mm where the transition temperature then decreased with further increase in grain size. The dilute additions of tungsten lowered the transition temperature for fine grain sizes, suppressed a reversal of the curve in the coarse grained portion, and raised the transition temperature for this region. The frequency of twin occurrence increased with increasing grain size and decreasing temperature. The object of the present investigation was to re-examine the effect of grain size on the brittle -ductile transition of pure iron and several dilute Fe-W alloys. Current literature normally presents a simple relationship between grain size and the brittle-ductile transition temperature, namely, that the transition temperature increases with increasing grain size. Heslop and etch' have studied the transition temperature of mild steel by V-notch Charpy impact tests for the grain size range between 200 and 6000 grains per sq mm. The result was a linear plot of In 1-1/2 vs brittle-ductile transition temperature, where 1 is the grain diameter. Recent experiments by sipos2 revealed the possibility of a reversal in the slope of the grain size vs transition temperature plot for pure iron; however, his investigation was limited in scope, and the data obtained were insufficient to permit a definitive curve. The present investigation was undertaken in an effort to confirm or extend the grain size effect observed in iron by Sipos. PROCEDURE All alloys were vacuum induction melted, using 99.95 pct Fe containing 0.03 pct 0 and 0.004 pct C. Four ingots were made, ranging from pure iron to iron with 0.035 pct W. The chemical composition of each alloy, after processing, is given in Table I. The four alloys were prepared as 45 lb heats and cast into 4 in. diam by 16 in. molds. They were then extruded into 3/4 in. rods at 1800oF. Specimens for chemical analysis, taken from various positions along the rods, revealed no variation in tungsten content along the length. The extruded rods were reduced to 0.156 in. diam stock by a series of cold swaging operations involving intermediate vacuum annealing treatments. This procedure yielded a final cold reduction in area ranging from 10 to 90 pct. The swaged rods were chemically cleaned, cold pressed to a cross section of 0.10 by 0.18 by 1.0 in. long (2.54 by 4.73 by 25 mm). The specimens were wrapped in iron foil and vacuum sealed (10-4 mm Hg) in quartz. Various heat treatments at temperatures from 700" to 1300oC were utilized to produce grain sizes from 8000 to 1 grain per sq mm. Grain sizes were determined by measuring the average area of grains in a polished section. In specimens with grain size greater than 20 grains per sq mm, the total number of grains in the cross section was counted and then divided by the area to yield grains per sq mm. Grain size was measured both for longitudinal and transverse cross sections. The average of the two measurements was plotted vs transition temperature. An Instron Table Model testing machine was used to determine the transition temperature of specimens tested in three point horizontal bending. The specimen was supported by two 1/4 in. dowels one in. apart. Bending was accomplished with a push rod, the end of which had an 1/8 in. radius. The head speed was 50 in. per min. Temperatures were established through the use

Jan 1, 1963

By D. H. Polonis, M. B. Kasen

AN unusual thermal etching phenomenon has been observed on the surface of a Cu-Si alloy. The observations were made during studies of vacancy condensation pit formation which were reported in previous papers.1,2 Figs. 1 and 2 are photomicrographs of the surface of a Cu-4.8 pct Si alloy after heating in vacuo (3 x X mm Hg) to 525°C and subsequently holding at that temperature for 16 hr in an impure (air-contaminated) argon atmosphere. Under these conditions preferential removal of silicon from the matrix by oxidation results in a surface which is entirely a phase overlying an a plus y structure. The light areas of Fig. 1 are regions in which very little thermal etching has occurred, while the majority of the surface has experienced severe etching. Similar regions in Fig. 2 are seen as plateaus above contours produced by net transfer of material from the specimen surface. Twin boundaries are also visible in Fig. 2. The difference in matrix mi-crostructure between Figs. l and 2 reflects the par- ticular orientation of low-index planes with respect to the surface of observation. Thermal etching contours of this type have been studied in detail by Hondros and Moore Both of the photomicrographs show that one or more dark spots are located approximately at the center of every protected area; where two spots are in close proximity, the protected areas have merged. The microstructures indicate that the anomalous resistance to thermal etching is related to the presence of these spots. Williams and Hayfield have shown that local regions of unusually high oxidation resistance can be caused by a surface monolayer of atoms with a work function higher than that of the base material. The result is an inhibition of the rate of electron removal from the base material and a decrease in the oxidation rate. The source of the protected layer may be either surface diffusion from contaminants on the specimen surface or pipe diffusion of solute atoms followed by migration across the surface. In the latter case the driving force is a difference in chemical potential resulting in a Gibbs adsorption phenomenon. In the present case, chemical polishing of the specimen surface precluded contaminants of a strictly surface nature. Consequently, diffusion of impurity atoms from within the lattice appears to be the most tenable explanation of the observed phenomena. The authors propose that the structures of Figs. 1 and 2 reflect the diffusion of impurity atoms along extended dislocations within the individual a phase grains prior to surface oxidation. The central spots within the protected regions are seen as sites of dislocation emergence which have become locally decorated with oxide in the manner discussed in Ref. 1. Williams and Hayfield observed protected regions adjacent to the grain boundaries of iron-contaminated copper which they attributed to the segregation of iron to the grain boundaries coupled with high dif-fusivity along the complex dislocation array at such boundaries. No evidence of such grain boundary protection was observed in the Cu-Si alloy; this

Jan 1, 1964

By R. C. Allen, Ralph Arnold

The writers have no new system and no new principle of taxation to propose. The general subject of taxation is as old as governments are and as familiar to taxpaying Americans as the general thesis on the inalienable rights of man. We believe, therefore, following the committee of the National Tax Association, that improvement in the general conditions of taxation, including mine taxation, maybe brought about mainly through a better adjustment of known and tried principles and methods of taxing to modern complex forms of property and income, and that not much is to be expected from abandonment of experience for new ways and means, methods and principles, should anything new be discovered, which in our opinion is very doubtful. The committee referred to has constructed the general framework of its Model System of State and Local Taxation1 on familiar forms of taxing, by eliminating some that ' have proved bad, suggesting improvements in others, and adopting the best, leaving plenty of room for the accommodation of the general plan to the varying conditions of taxation in the several states. Unfortunately, the taxation of mines is dismissed by the committee with the statement that the subject has been reassigned for further investigation and report by a special sub-committee, frankly recognizing that the peculiar difficulties of this phase of the subject require special study and investigation. Much may be hoped for from the labor of this sub-committee if the problem is approached from the viewpoint of recommendations already published. In this paper, the writers state their opinion on some of the broader aspects of mine taxation with too little attention to the grounds on which they rest. Contrary to inclination space requirements compel them to resort to summary statements without adequate discussion for a satisfactory presentation of the whole subject. All they can do is to qualify the witnesses and record the testimony. The senior writer was introduced to the practical aspects of the subject of this paper in 1913, when, as State Geologist of Michigan, he was

Jan 1, 1920

By Robert H. Richards, Richard W. Lodge

A great deal of speculation, as well as actual experiment, has been devoted to ascertaining the changes in the materials (luring their descent in an iron blast-furnace, affecting (1) the chemical constitution, (2) the mechanical condition, and (3) the arrangement of the materials. With a view to throw some light upon the third question, we constructed a model and tried experiments which are here described. Our model is a vertical section of a furnace, with the lines of the Edgar Thomson furnace D of 1885 for the use of which we arc indebted to Mr. Gayley. The model is 40 inches high, and made to scale (1/2 inch equals 1 foot), and the horizontal section of the space through which the charge falls at any point in the descent is 11/2 in. x d, d being the diameter of the furnace at that place. We are unable to say just where the idea of making this model came from ; perhaps, partly from The Principles of the Manufacture of Iron, and Steel, 1884, I. Lowthian Bell, p. 124 ; partly, also, from

Jan 1, 1888

By E. J. Ripling, S. I. Liu

IT has been shown in a number of recent publications that much information on the mechanical behavior of metals can be gleaned by first deforming test specimens under one set of conditions, and then evaluating the effect of this deformation by means of a subsequent tensile test. A straining procedure of this type has been applied to study the flow behaviors of a number of metals.1, 2 In these studies the prestraining and testing were both tensile strains, while the straining temperature was varied between the prestraining and testing steps. These data indicate that there is a more or less general flow behavior exhibited by all metals which are pre-stretched at one temperature and then tested in tension at a second temperature. Prestraining a metal at a high temperature produces a lower yield strength during the subsequent low temperature strain than would the same total strain at the lower temperature. On reversing the order of the strains, low temperature prestraining produces a higher yield strength during the subsequent high temperature straining than would a single high temperature strain of the same magnitude. Unlike the flow behaviors, the fracturing characteristics of metals when prestrained under one set of conditions and tested under a second set of conditions is quite material dependent. The fracture behavior of a number of steels2" as well as of a commercially pure zinc,4 have been investigated by these two-step tests and was found to depend upon the position of the transition temperature with respect to the prestraining and testing conditions. Since these fracturing phenomena are complicated by the appearance of the transition temperature, it has been difficult to reliably define the basic effect of a two-step straining procedure in fracturing. Metals crystallizing in the face-centered cubic system do not exhibit transition temperature effects so that the mechanical characteristics obtained on these materials could serve as a base for two-step straining behaviors. Consequently groups of specimens of the aluminum alloy 24s-T4 were prestrained various amounts at room temperature in either tension or compression after which these strained specimens were further strained to failure, or tested in tension, at either room or some lower temperature. Other groups of 24S-T4 specimens were prestretched at various low temperatures after which these were tested in tension at room temperature. These straining techniques then made it possible to compare the behaviors of aluminum with the behaviors previously presented for steels. Material and Procedure The commercial aluminum alloy 24S-T4 in the form of 3/4 in. rods was used in this investigation. The material was subjected to the following treatments before machining: 1—resolution treating at 920" & 10°F for 45 min, 2—quenching in water at room temperature, and 3—aging at room temperature for four days. The re-heat treated material was then machined to either of the specimen shapes shown in Fig. 1. Fig. la shows the threaded-end specimen used for prestraining in compression. Fig. 1b shows the specimen used for both prestrain in tension and final testing. The material subjected to precompression in the form of the specimen shown in Fig. la was re-machined to the specimen shape in Fig. 1b for final testing. Prestraining in tension and final testing were done without any intermediate machining. All straining was performed on a 10,000 1b Riehle tensile testing machine. Tensile strains were conducted in a specially designed concentric fixture which produced an eccentricity of less than 0.001 in." The change in diameter at the minimum section of

Jan 1, 1954

By B. H. Kear, S. M. Copley

A dynamic theory of precipitation hardening in alloys containing cohevenl, stvess-.free, ordered particles is developed. The yield stvess is predicted from the stress dependence of the plastic strain vale, which is related to a derived dislocation velocity-stress function. The theory is shown to predict the magnilude and temperature dependence of the yield stress of a commercial nickel-base superalloy as well as many details of its slip structure. GLEITER and Hornbogen have developed a theory of the yield stress in alloys hardened by coherent, stress-free ordered ptrticles based on the observation that dislocations (b = a/2 (110)) glide in pairs.' When a dislocation pair shears through an ordered particle, the glide motion of the leading dislocation is impeded since it must create antiphase boundary (APB), whereas the motion of the trailing dislocation is assisted because it annihilates APB produced by the first one. Taking into account the APB energy, the size, and spacing of the particles, G-H predict the observed yielding behavior in Ni/18.8 Cr/6.2 A1 alloys composed of a matrix phase y '(nickel-solid solution) and particles of y' (basically Ni3A1). The G-H theory, as well as all previous theories of hardening by coherent ordered particles, do not include the details of dislocation motion; the present dynamic theory is an attempt to overcome this limitation. In the dynamic theory, the yield stress is predicted from the stress dependence of the plastic strain rate, which is related to a derived dislocation velocity-stress function. This function can be evaluated if the structure of the alloy, the APB energy of the ordered phase, and the characteristic drag or frictional stresses of the matrix and precipitate phases are known. The theory is shown to account for the observed temperature dependence of the yield stress in a commercial nickel-base superalloy. 1) NICKEL-BASE SUPERALLOYS Although their compositions are complex, the nickel-base superalloys have remarkably simple structures. A detailed examination of the commercial superalloy

Jan 1, 1968

By John Birkinbine

" Whether an iron-ore should be roasted is a question which very seldom arises ; at least, this question seldom ought to arise. With the exception of the red impalpable oxide, the whole series of ironores require roasting—even the specular iron-ore, if it is very compact—but the best oxide, if too compact, works badly in the furnace. All other ores should be subjected to calcination. Some ironmasters are in the habit of using the hydrates raw, but this should riot be done where clay-ores are smelted or where the hydrates contain either chlorides or phosphates. But in the latter case, the pig metal will be cold-short if there is too much phosphorus. Under all circumstances, however, it is best to roast the ores if we expect good metal and well-regulated furnace operations. " The object of roasting ores is to produce higher oxidation and to expel injurious admixtures. In both cases liberal access of atmospheric air is required ; we should, therefore, so arrange our roasting operations as to fulfil these conditions, from which it will appear that different ores require different treatment."* The above may be considered an extreme, and perhaps erroneous view; but there is no question as to the absence of a general appreciation concerning the value of preparing ores of iron for smelting in the blast-furnace.

Jan 1, 1884

By H. P. Greenwald, H. C. Howarth

The rapidly increasing use in coal mines of portable auxiliary fans, which are generally 'blowers" employed in connection with canvas tubing, raises questions concerning the hazards of such equipment, especially where the practices are opposed to established methods of ventilating face workings. Half a dozen or more coal-mine explosions and some fires have been attributed to the use of auxiliary fans; moreover, competent mining engineers have found many dangerous installations and methods of use-for example, intermittent running of the fans in gassy mines with consequent accumulations of firedamp at the faces. These facts have led the U. S. Bureau of Mines to issue this recommendation: "In the interest of safety, the Bureau of Mines, Department of Commerce, recommends that auxiliary fans or blowers should not be used in coal mines as a substitute for methods of regular and continuous coursing of the air to every face in the mine." The comparatively recent introduction of new types of mining machines, mechanical loaders, face conveyors, and slabbing machines has encouraged the trial of new systems of face mining, all of which have for their object the rapid advance of the faces. Although the latter has certain economic advantages, in gassy mines the rate at which gas is given off is generally found to increase in proportion to the speed of advance into new territory, which in turn increases the difficulties of efficient ventilation of the face workings. Some of the systems of advance mining being tried in connection with new mechanizing methods practically compel the use of blower fans and tubing, as single narrow places arc now driven 300 ft. or more without crosscuts. In some instances a series of parallel headings are driven without crosscuts pre-

Jan 1, 1928

By H. P. Greenwald

THE rapidly increasing use in coal mines of portable auxiliary fans, which are generally "blowers" employed in connection with canvas tubing, raises questions concerning the hazards of such equipment, especially where the practices are opposed to established methods of ventilating face workings. Half a dozen or more coal-mine explosions and some fires have been attributed to the use of auxiliary fans; moreover, competent mining engineers have found many dangerous installations and methods of use-for example, intermittent running of the fans in gassy mines with consequent accumulations of firedamp at the faces. These facts have led the U. S. Bureau of Mines to issue this recommendation: "In the interest of safety, the Bureau of Mines, Department of Commerce, recommends that auxiliary fans or blowers should not be used in coal mines as a substitute for methods of regular and continuous coursing of the air to every face in the mine." The comparatively recent introduction of new types of mining machines, mechanical loaders, face conveyors, and slabbing machines has encouraged the trial of new systems of face mining, all of which have for their object the rapid advance of the faces. Although the latter has certain economic advantages, in gassy mines the rate at which gas is given off is generally found to increase in proportion to the speed of advance into new territory, which in turn increases the difficulties of efficient ventilation of the face workings. Some of the systems of advance mining being tried in connection with new mechanizing methods practically compel the use of blower fans and tubing, as single narrow places are now driven, 300 ft. or more without crosscuts. In some instances a series of parallel headings are driven without crosscuts pre-

Jan 1, 1928

By J. L. Huiatt, G. M. Potter, R. B. Tippin

The US Bureau of Mines and Great Salt Lake Minerals and Chemical Corp. have developed a froth flotation process for concentrating potassium salts from Great Salt Lake solar evaporites containing about 6% K2O. The crude evaporites, which were predominately halite (NaCl) with smaller amounts of kainite (KCl.MgS0, 2.7Hp0) and schoenite KeS0,MgS04.6H,0), were conditioned in a saturated brine solution., thus converting nonfloatable kainite to the floatable mineral schoenite. Schoenite was then selectively floated with a medium-molecular-weight fatty acid. Continuous small-scale pilot-plant testing indicated that 80% of the potassium could be recovered from the crude evaporites in flotation concentrates assaying about 13% K2O.

Jan 1, 1976

By F. L. Wolf

THERE is a tendency on the part of practical foundrymen to accept with reluctance the results of tests on sands, binders, and. such materials made in the chemical laboratory alone. They feel that such tests frequently emphasize and measure properties that are of minor importance and fail to take account of characteristics that are important in determining the value of the material in actual practice. Experience seems to indicate that the most thorough and conclusive, test for any new foundry material is an actual run in the foundry alongside of a standard material of known value. Such a test, however, involves certain difficulties and necessitates certain precautions. It is not always easy to obtain a fair trial for a new material. We all have certain prejudices, which unconsciously affect our judgment to a marked degree. A practical test frequently involves so many workmen, each of whom reacts in a different manner to the test, that; the personal equation becomes very, complex and the true results of the test are obscured. There are times, too, when a thorough experimental trial of a material would interfere too much with the rush of work in a department or would hazard the quality, of the product to such an extent as to make it inadvisable. Under such conditions a laboratory test is advisable before the material is sent into the foundry. These tests should be made as practical as possible and so closely related to foundry practice as to give a true index to the value of a, product for the purpose desired. Core sands and molding sands are as numerous "as the sands of the sea" and vary as much in quality. Old sources of supply are continually failing and new ones must be opened, so that we must continually search for new and better grades of sand. During the past year, the Ohio Brass Co. has developed tests for sands', cores, and binders which bear a close relation to the particular use to which these materials are put in

Jan 9, 1920

By Dean F. Winchester, C. D. Johnson

The so-called Rocky Mountain region is here made to include Colorado, Idaho, Montana, northern New Mexico, Utah and Wyoming, an area of great distances and relatively sparse population. Conditions of distance, transportation and markets have had their retarding influence on devolopment and production but the increase in facilities and markets in recent years has provided additional incentive for more thorough search for new productive areas and the more complete development of the known fields. The low prices of crude during the past year have offset, to a certain extent, the desire for increased production and much of the effort has been directed therefore to outlining new areas rather than to attempts to increase production from known fields and thereby add to the already sufficient supply above ground. During the year just closed the Rocky Mountain region has seen consistent efforts to outline new areas and these efforts have been reasonably successful. In this area a very large part of the land is government property, and by cooperation between the government, the private owner and the company it has been possible to carry on development in a scientific manner, providing for the maximum recovery of valuable products at least cost and at times when prices were best. Due to the fact that in the Rocky Mountain region costs of exploration and development are relatively high because of natural circumstances, it has been the policy of operators to drill test wells only on structures where they controlled a large proportion of the land. Even community lease programs have been effected in certain areas, thus obviating the necessity of offset drilling and the attendant uneconomical and even wasteful production. Oil production in the Rocky Mountain states has shown a slight increase during the year, the average daily production for November being 78,124 bbl. as against an average in January of 76,681 bbl. The total production during the first 11 months of the year, according to the U. S. Burcau of Mines, was as follows:

Jan 1, 1929

By Daniel R. Hull, H. F. Silliman, Earl W. Palmer

The brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6¾ in. wide by I in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breakdown rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause—however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

The brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6¾ in. wide by I in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breakdown rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause—however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By Willis T. Burns

I. Introduction.......................................... 703 II. History................................................ 703 III. General Description of Plant......................... 704 IV. AnoDes................................................. 711 V. Cathodes............................................... 714 VI. Electrolyte............................................ 718 VII. Electrolytic Slime..................................... 727 VIII. Power................................................. 728 IX. Operating Details..................................... 732 X. Furnace Refining...................................... 736 XI. Physical Testing oF Products.......................... 739 I. Introduction. These notes are submitted, not as a discussion of the modern practice of electrolytic-copper refining, but as the record of a refinery that was among the pioneers in the field and that is to-day, and has been for 17 years, operating under conditions not to be found in any similar plant in the country. I refer to the current density, which is at least 60 per cent. higher than that regularly employed elsewhere, and to the fact that the anodes treated are the direct product of the converter rather than of the reverberatory furnace. The writer has no knowledge of any other refinery treating anodes of this character. II. History. This refinery, now one of the oldest plants of its kind operating in this country, was built in 1892 by the Boston & Montana Consolidated Copper & Silver Mining CO. to refine the product of its Great Falls reduction works. The estimated capacity of the plant as designed was 65,000 lb. of cathodes per day at a current density of 16 amperes per square foot.

Jan 1, 1914

By S. F. Shaw

The theory that maintaining a high back-pressure on the oil sand lowers the viscosity of the oil has been generally accepted. The theory has also been advanced that lower viscosity permits the oil to be moved through the sand to the well at an expenditure of less gas per barrel of oil than would otherwise be required. It seems reasonable to assume that production of oil at the minimum gas-oil ratio will result in a greater ultimate recovery of oil. During the past five years the writer has acquired data on thousands of tests made on wells to determine the best rate at which to produce them. In the majority of cases reduction in back-pressure did not definitely increase the gas-oil ratio. The information obtained from these tests has raised doubt in the mind of the writer as to the correctness of the theory that lowered viscosity results in lower gas-oil ratios and in higher ultimate recovery of oil. The reasons that explain the results obtained in these tests cannot yet be definitely stated, but the hypothesis is being tentatively assumed that there are other factors which outweigh the influence of viscosity. Energy in Gas Moves Oil to Well The general opinion is that in most cases it is the energy in the gas that moves the oil to the well. In wells flowing naturally it is also the energy in the gas that lifts the oil to the surface. In a flowing well, there are two very distinct operations: 1. Moving the oil through the sand to the well. 2. Lifting the oil to the surface. The more important function of the gas is that of moving the oil to the well. Means for lifting the oil can always be found once it has been delivered to the well. Principles Involved in Lifting Oil A well that flows naturally is the same as a gas-lift well except that all of the gas is supplied by the oil reservoir. This natural flow is subject

Jan 1, 1931

By Richard L. Gordon

THE PROBLEMS AND POSSIBLE SOLUTIONS Toward the end of the 19th century, American industry began a drastic reorganization. The many, small, often-regional firms were supplanted by large national corporations-often produced by mergers among the existing firms. Giant companies appeared throughout American industry and many of them were engaged in the mineral industries.a The largest combines, by far, to emerge during the period were United States Steel and Standard Oil. Long before the restructuring had run its course, widespread concern arose over the process of concentration. Efforts were made to control, if not stop, the transformation. The concern produced the Sherman Antitrust Act of 1890 and the first of many federal regulatory agencies-the Interstate Commerce Commission (see Refs. 24, 31, 42). The basic objectives of these policies remain unclear to this day. The crucial issue is whether the goal is primarily to insure development of a more competitive economy or to preserve a social structure leaving more scope for small businesses. Complications arise from difficulties in agreeing upon the meaning of these terms. Studies of the early years of the antitrust movement suggest that it involved no particular concern over the mineral industries. Objections were directed at big companies in general. To be sure, the conservation movement arose in roughly the same period and did stress the evils of monopoly control of minerals. However, direct, continuing influence of conservation policy on antitrust is not apparent. Many of the most important antitrust cases, nevertheless, involved minerals. This, of course, may be sheer coincidence; the choice of cases has never followed any obvious pattern. Certainly, no simple hypothesis can explain the interest consistently. Once it may have been true that mineral industries were more likely than other sectors to be dominated by a few large companies. Yet, often sharp reversals of such tendencies -e.g., in oil and aluminum-have not removed antitrust interest. The importance of minerals to the economy cannot satisfactorily rationalize antitrust interest. The equally

Jan 1, 1976

By R. L. Bleifuss

Most pellets swell only slightly during reduction, but some swell so enormusly that their increase in size is termed catastrophic. Since catastrophic swelling produces irregularities in blast furnace operation, an understanding of the phenomenon is of practical as well as theoretical interest. Observations have shown that catastrophic swelling is characterized by the growth of a network of fine iron filaments. Evidence is presented to show that the growth of these filaments is promoted by the presence of calcium in the magnetite lattice of the original ore. During reduction, the limited mutual solubility of CaO and FeO produces an unstable condition that inhibits the uniform nucleation of metallic iron. Other elements in the magnetite lattice whose oxides are continuously soluble in FeO in the critical temperature range have no effect. Magmatic segregation or pyrometasomatic replacements are the most likely deposits to contain calciferous magnetite. Over the past few years there has been an increasing concern throughout the iron and steel industry over the tendency of pellets to swell during reduction. Although the tendency for swelling is only one of several attributes that determine the behavior of pellets in the blast furnace, swelling-reduction tests are now part of the normal evaluation procedure of many pellet consumers. During a swelling-reduction test, pellets display either the moderate increase in size known as normal swelling, or the enormous expansion known as catastrophic swelling. This paper is concerned with the origin and control of catastrophic swelling and how it is enhanced or inhibited by the presence of minor elements. Swelling Behavior The swelling behavior of pellets during reduction is indicated in Fig. 1. The lower curve represents normal swelling and the upper curve catastrophic swelling.' During the initial stages of reduction, that is, up to about 20-25% reduction, the two curves are considered to be equivalent. Beyond this point normal pellets undergo a gradual decrease in size with increased reduction. By contrast, pellets which exhibit catastrophic swelling show a second dramatic expansion between 25 and 70% reduction. The initial normal swelling develops as the hematite of the pellet is successively reduced to magnetite, and then to wustite. Work by Edstrom' and others has shown that the reduction of hematite to magnetite is accompanied by a 25% volume increase, whereas the magnetite to wustite stage shows a volume decrease. The volume increase overlaps the wustite field because magnetite is formed simultaneously with the wustite during topochemical reduction of the pellet. The catastrophic expansion is clearly related to the wustite, to

Jan 1, 1971

By S. C. Riemer, I. Iwasaki, J. N. Orlich

The effects of percent solids, mill loading, and grinding time on product size distribution and ball wear were studied in a laboratory ball mill for a taconite ore. Mild steel balls and HCLA steel balls were used to examine the role that ball hardness play in grinding. Net production of - 44-µm (- 325-mesh) material reached maximum at 70% solids, whereas the ball wear decreased as pulp density increased. HCLA steel balls ground the taconite ore finer than mild steel balls under otherwise identical conditions. Examination of ball surfaces with a scanning electron microscope suggested that corrosive wear was mini- mal under nitrogen flushing conditions, and that grinding with mild steel balls involved nipping rather than attrition, whereas grinding with harder HCLA balls involved both nipping and attrition. Pulp viscosity controlled the thickness of pulp layer on balls, thereby affecting grinding efficiency and ball wear.

Jan 1, 1986