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By Orville R. Lyons, A. C. Richardson

F. X. Ferney—We are pleased that this paper was presented at this meeting and thank Mr. Richardson and Mr. Lyons for their effort and work in preparing it. We agree with the authors that it was unfortunate that more comprehensive data were not available when the paper was prepared, this being particularly true since we had no knowledge that the paper was being written and could not make available data which were in our process files. Further, it is our opinion that because the data are not sufficiently comprehensive the results which are presented are erratic and will lead to false conclusions. As we see it, there are three Specific reasons why the data which are presented cannot be considered accurate. 1. The preparation plant was not at equilibrium while the samples were being taken. This is indicated by the fact that the percent of solids in the circulating water varied from 3.9 pct to 10.7 pct during the period when the plant was sampled. 2. We do not believe that the samples of Bird feed which were taken were representative and could indicatc the true feed to the filter. Evidence of this is shown in the data where the dewatered product leaving the centrifuge contains more coarse material than the feed to it, that is, material which is +6-mesh in size. 3. We question if the data concerning screen analysis in the fine sizes is accurate and would conclude (from the data) that these tests were made by a dry-screen method. We have found that wet screening is always necessary to obtain a true picture of the quantity of —200-mesh fines which is present. The test work described in the Lyons-Richardson paper was conducted some time ago and the tests were carried on during a period when the preparation plant had not ironed out all of their start-up problems. Since that time most of these problems have been corrected and now this is a smooth running, well-operated prep-

Jan 1, 1951

By Orville R. Lyons, A. C. Richardson

F. X. Ferney—We are pleased that this paper was presented at this meeting and thank Mr. Richardson and Mr. Lyons for their effort and work in preparing it. We agree with the authors that it was unfortunate that more comprehensive data were not available when the paper was prepared, this being particularly true since we had no knowledge that the paper was being written and could not make available data which were in our process files. Further, it is our opinion that because the data are not sufficiently comprehensive the results which are presented are erratic and will lead to false conclusions. As we see it, there are three Specific reasons why the data which are presented cannot be considered accurate. 1. The preparation plant was not at equilibrium while the samples were being taken. This is indicated by the fact that the percent of solids in the circulating water varied from 3.9 pct to 10.7 pct during the period when the plant was sampled. 2. We do not believe that the samples of Bird feed which were taken were representative and could indicatc the true feed to the filter. Evidence of this is shown in the data where the dewatered product leaving the centrifuge contains more coarse material than the feed to it, that is, material which is +6-mesh in size. 3. We question if the data concerning screen analysis in the fine sizes is accurate and would conclude (from the data) that these tests were made by a dry-screen method. We have found that wet screening is always necessary to obtain a true picture of the quantity of —200-mesh fines which is present. The test work described in the Lyons-Richardson paper was conducted some time ago and the tests were carried on during a period when the preparation plant had not ironed out all of their start-up problems. Since that time most of these problems have been corrected and now this is a smooth running, well-operated prep-

Jan 1, 1951

By Edgar C. Moxham

THE paper of Mr. W. H. Adams, read at the Cleveland Meeting, June, 1891 (Trans., xx., 196), on "The First Iron Blast-Furnaces in America," establishes the interesting fact that the earliest operations on this continent in the manufacture of pig-iron were based upon a deposit which, after many years of neglect, has now become again the object of active exploitation. In addition to the remarks of Messrs. Pechin and Raymond in discussions of the paper above cited,

Jan 1, 1893

By W. L. Chen

The Batac jig was first introduced in the US for fine coal cleaning in 1973 (Tackett, 1977; Hake, 1976). Since then, a total of six such jigs of various sizes have been installed in five US plants for a total capacity of 2346 t/h. The raw coal size ranges from 19 mm x 0 to 9.5 mm x 0-fraction sizes previously fed to heavy medium cyclones, Deister tables, or water only cyclones. Growing interest in the Batac jig as a replacement for the above equipment is due to the following reasons: • Unlike heavy medium cyclones, no magnetite is required. As a result, the operating cost of the plant is reduced. • The compactness of equipment is unique on a unit ton per hour basis as compared to other equipment. • Solid state electronic control of jig stroke length, frequency, and jig bed depth makes the equipment highly efficient. Installations of Batac jigs in the US as of June 1980 are shown in [Table 1]. Use of the Batac jig is even greater outside the US (Anonymous, 1980; Chen, 1980). Its use is not limited to fine coal but is applied to coarse coal as well, with 102 mm size in the feed (Zimmerman, 1975). In countries where consumption of magnetite associated with the heavy medium system of coal cleaning is considered a waste of iron ore resource, the Batac jig is regarded as the primary choice in the selection of cleaning equipment (Chen, 1980).

Jan 1, 1981

By P. B. Liebermann

THE resistance to motion offered by mine cars is caused principally by: Rolling friction, flange friction, bending rails, bearing friction and wind resistance. With proper construction and with a fair amount of attention and care, that is, under favorable conditions, the first three items cannot be greatly improved. The wind resistance ordinarily is negligible on account of the slow speeds commonly used. The bearing friction, however, is a variable item, depending upon the design, the bearing material, the lubrication, the location (whether in wheel-hub or on car-body) and the alignment. Under the most favorable conditions the bearing friction will reach a lowest possible value. By the development of a successful anti-friction mine-car bearing this lowest value has been improved to such an extent as to affect the whole system of mine haulage. After being satisfied of their durability and certainty of operation, any investigation into the advantages of anti-friction bearings for mine cars will have to be based upon reliable information as to the saving in power of such bearings. While numerous tests have been made in this direction, the results have not always been convincing, principally because of the rather crude methods that were employed. These crude methods are the main cause of the wide variations existing in regard to the exact amount of the frictional resistance. Frequently an ordinary spring balance is used and the pull necessary to move a certain car or train of cars is obtained by a number of readings. Such spring balances necessarily have a coarse graduation and the continuous vibration and fluctuations to which they are subjected make them highly dependent upon the individual observer. Further, they must be frequently calibrated. Sometimes these tests were made without regard to acceleration, speed or even grade.

Jan 6, 1916

By M. E. Nicholson

The solid solubility of boron in iron has been determined by saturating iron with respect to FeyB at several temperatures from 870° to 1135 C. In alpha iron the maximum solubility was found to be 0.002 pct B and in gamma iron the solubility varied from 0.001 pct at 915°C to 0.020 pct B at 1165OC. The eutectic and peritectoid temperatures were found to be 1165° and 911 °C respectively and the gamma iron solidus was located approximately at 0.020 pct B. RECENT investigations of boron-treated steels', ' indicate that the solubility of boron in austenite is of the order of 0.003 pct at 900°C. This has led to the general belief that the solubility of boron in a and r iron is considerably less than that indicated by Wever and Muller." Therefore the solid solubilities of boron in a and r iron have been re-determined. The eutectic and peritectoid temperatures were also remeasured and the r-iron solidus was studied in some detail.* In 1929 Wever and Miiller investigated the phase equilibria of Fe-B alloys. Fig. 1 shows the solid solubility region of the Fe-B diagram based on their investigation. They found that boron lowered the A, transformation temperature to 1381 °C where saturated 6 solid solution "which must contain about 0.15 pct B" and "r solid solution containing about 0.10 pct B" are in equilibrium with liquid containing 1.9 pct B. At the eutectic temperature of 1174"C, 7 solid solution was found to contain "about 0.15 pct B." A peritectoid relation was found to exist between a and y iron with an invariant temperature at 915 "C, where the boron solubility in 7 iron was "about 0.10 pct B" and the solid solubility in a iron "did not exceed 0.15 pct B." Although most of their

Jan 1, 1955

By H. S. Geismer

There are three general methods available for obtaining commercial brown iron-ore: hand-screening; washing; and washing and concentrating. Hand-screening has produced a large tonnage of ore in the past, but is rapidly falling into disuse, except as a preliminary step, largely because modern furnace-practice requires all forcigii material to be separated from ores before they are deliv-

Jan 1, 1912

By H. F. Walther

Basic electric-are furnace steel production mainly involves the use of two separate types of slags. The first, known as the "melt down" or oxidizing slag, which is in most cases removed from the furnace mechanically, and the heat finished under the second or deoxidizing slag, which is commonly known as the "finishing slag.'' The melt down slag is formed by the addition of lime or limestone to the charge, which combines with the oxides formed during the melting period and the product of any bottom erosion that may take place.

Jan 1, 1935

By J. M. Hodge, M. A. Orehoski

The relationship between hardenability based on a 50 per cent martensite criterion, and that based on higher percentages of martensite in a number of low-alloy steels was discussed in a previous paper by the authors.' It was found that the differences between the hardenability values based on the 50 per cent martensite and full martensite criterions increased as the hardenability increased and that, in the steels of higher hardenability, these differ-

Jan 1, 1947

By M. A. Orehoski, J. M. Hodge

The relationship between hardenability based on a 50 per cent martensite criterion, and that based on higher percentages of martensite in a number of low-alloy steels was discussed in a previous paper by the authors.' It was found that the differences between the hardenability values based on the 50 per cent martensite and full martensite criterions increased as the hardenability increased and that, in the steels of higher hardenability, these differ-

Jan 1, 1947

By H. F. Walther

Basic electric-are furnace steel production mainly involves the use of two separate types of slags. The first, known as the "melt down" or oxidizing slag, which is in most cases removed from the furnace mechanically, and the heat finished under the second or deoxidizing slag, which is commonly known as the "finishing slag.'' The melt down slag is formed by the addition of lime or limestone to the charge, which combines with the oxides formed during the melting period and the product of any bottom erosion that may take place.

Jan 1, 1935

By Charles Kirchhoff

For twenty years it has been my work to watch and record progress in both the technical and the commercial branches of mining engineering in the wide sense in which it is represented by our Institute. While you who have been actively engaged in our profession have made history, a few of us have attempted to be the historians and have been kept keenly on the qui vive to follow the developments of so broad a field. One so employed may be pardoned if he ask you to pause for the unusual purpose of looking backward, that you may measure what you and others have done, and that the younger men may gather inspiration from the work accomplished by their elders and their predecessors. It is not so long since that the commercial management dominated our industries. Bred in the school of science, which seeks its reward in establishing the truth, our engineers were sometimes indifferent to trade conditions and requirements. Much of that feeling has disappeared, and the engineer recognizes that it is his mission to apply the achievements of science to a useful commercial end. On the other hand, business men now understand that the utilization of our natural resources and the production of articles for consumption is impossible without the intervention of the engineer. They must co-operate, unless, indeed, the two functions are combined in one man —a rare but powerful combination. Now the final measure of success of both is the cost sheet on the one hand and the expansion of markets on the other, so closely interwoven, so mutually interdependent. There is one cardinal feature, however, which characterizes the engineer's work—namely, the permanence of his achievements. Every improvement, particularly when it has been recorded in such lasting form as a paper in the Transactions of our societies—

Jan 1, 1900

By Ta M. Li, John D. Wiebmer

Record high prices, burgeoning exploration programs, mine-mill openings, and plant expansions have all characterized a dramatic: resurgence of the US uranium industry in recent years. But while the bull is leading the way on the production side of the nuclear fuel cycle, there is reason for caution from the end-users' viewpoint. How fast will electrical demand grow in the years to come, and what portion of that will nuclear generators supply? How do utilities play their cards when the government holds two of the largest jokers in the deck-a policy on spent fuel reprocessing and a timetable for the fast breeder reactor? Is there a shortfall in domestic uranium supplies on the horizon?

Jan 10, 1978

By L. L. Handy

Solvent floods using slugs of solvent have been found to show continuity in behavior from the vapor pressure of the solvent to the critical pressure for the two-component driving gas-solvent system. In the pressure region between the solvent vapor pressure and the critical pressure for the gas-solvent system, the gar and solvent are only partially miscible. Although complete miscibility cannot be obtained at these pressures, complete oil recovery is possible in principle. In two-phase solvent floods the solvent is propagated tllrough the reservoir, primarily, in the vapor phase. The carrier gas requirements constitute a significant factor in the economics of the process. A qualitative theory is proposed for estimating the amount of dry gas required to move the solvent through the reservoir. The theory shows that for two-phase solvent floods the total gas needed is a minimum at the vapor pressure of the solvent and at the critical pressure for the gas-solvent system, and is a maximum at some intermediate pressure. The predictions of the theory are supported by experimental studies using methane, butane and decane or methane, propane and decane in a natural sandstone core. INTRODUCTION Previously, solvent slug processes have been found effective for oil recovery in two pressure ranges. First, conventional miscible displacements are possible at pressures greater than the critical pressure for the gas-solvent system. Second, Jenks, et al,' have shown that, at pressures slightly in excess of the vapor pressure of the solvent, a solvent slug can be propagated through a reservoir by a gas essentially insoluble in the liquid solvent. The solvent bank displaces the oil ahead of it. Both of these processes, at least ideally, are capable of recovering all of the oil in the swept regions. Slug processes for which the gas and solvent are partially miscible have not been considered; that is, those systems for which the solvent and driving gas form two equilibrium phases in which the vapor phase contains a significant amount of solvent and the liquid phase an appreciable amount of the driving gas. Welge and Johnson' have shown that the gas needed to movc a solvent slug through the reservoir increases with increasing pressure above the vapor pressure of the solvent. It will be shown that solvent slug processes can, theoretically, recover all of the oil at any pressure greater than the vapor pressure of the solvent. But the amount of gas required to move the solvent through the reservoir depends very much on the pressure and temperature. In the present study a maximum in the gas requirements was both predicted theoretically and observed experimentally. This result has not been reported previously, and would not have been predicted from the Welge and Johnson model. The gas requirements are a minimum at the pressures corresponding to the vapor pressure of the solvent and again at the critical pressure for the gas-solvent system, and are a maximum at some intermediate pressure. AN APPROXIMATE THEORY FOR TWO-PHASE SOLVENT FLOODING The differences and similarities between conventional solvent floods and two-phase solvent floods are best understood by referring to concepts developed for miscible displacement in which miscibility is generated in the reservoir. In Fig. 1(A), a ternary diagram is shown for a hypothetical gas-solvent-oil system. To be rigorous the three components should each consist of a single molecular species. The pressure for Fig. 1(A) is greater than the critical pressure for the binary gas-solvent system at the specified temperature. Diagrams of this type are the ones most frequently referred to in discussions of enriched-gas drive and miscible displacement. A limiting tie line is shown tangent to the two-phase envelope and intersecting the gas-solvent line at Point A. To obtain generated miscibility with this type system, others have shown that, for an oil of Composition D, a mixture of gas and solvent must be injected which is richer in solvent than that composition indicated by A. An oil repeatedly contacted with a gas phase richer than A changes toward a composition which would be at equilibrium with the injected mixture, that is, a composition lying on a tie line which passes through the injected-gas composition. Since no such tie line exists, the oil is enriched to the point at which it becomes directly miscible with the injected mixture. At pressures lower than the critical pressure for the gas-solvent system, other types of phase diagrams are observed. The ones of interest in this paper are for pressures greater than the vapor pressure of the solvent, but less than the critical pressure of the gas-solvent system. Such a ternary diagram is shown on Fig. 1(B). In this case, two-phase behavior is observed not only for gas-oil mixtures, but also for certain compositions in the gas-solvent system. If a gas of Composition A (a dew-point vapor) is injected, once again the original oil is enriched by successive

By R. E. Sheppard, A. O. Martel

Zinc sinter plant fume is roasted to selectively sulfate the cadmium. Water leaching of the roasted fume recovers about 80% of the contained cadmium and produces solutions containing about 40 grams per liter cadmium and 10 grams per liter zinc. The solution is treated with sodium bichromate for lead removal. Cadmium sponge, precipitated with zinc dust, is briquetted, melted, and cast into commercial shapes. The residue from the water leach is acid leached with waste acid, solubilizing the zinc and residual cadmium. Impure cadmium sponge, precipitated with zinc dust, is separated from solution with cyclones and dewatered in a centrifuge. Air-oxidation- acid leaching of the impure sponge resolubilizes the cadmium. The resulting solution is neutralized, clarified, and treated for cadmium recovery with the water leach solution. The residue from the leached fume is water-washed and recovered in a centrifuge-thickener circuit. This residue contains lead sulfate and significant quantities of gold and silver. Manpower requirements are held to a minimum by automating operations within the Leach Plant.

Jan 1, 1973

By Carl O. Thieme

INDUSTRIAL specialization has rapidly created a demand for new and better alloys. A more thorough understanding of the requirements of specific industries and the discovery of processes by which it has been made possible to utilize certain metallic elements in larger quantities, together with greater purity in most virgin metals, has resulted in a great increase in the number and variety of alloys. This increase in the number of elements entering into non-ferrous alloy manufacture has increased the contamination in secondary metals, as received by the smelter. In order to successfully refine scrap of a much more complex nature it has been necessary for the smelter to install new equipment and to constantly search for new methods of refining as well as to improve the methods already in use. In some instances it is largely responsible for specialization in the secondary metal industry. It is usually necessary to remove the contaminating impurities in scrap or eliminate to a degree not objectionable, no matter how introduced. In order to know what metals or elements are of an objectionable nature, the smelter must make a study of the effect of single elements and combinations of elements on many of the physical and mechanical properties, such as strength, ductility, color, hardness, casting soundness, etc. The smelter of secondary metals must be able to utilize scrap materials of all kinds, for, sooner or later, most fabricated metal parts and the waste products formed during the process of manufacture find their way to the smelter. In addition, the smelter, in contracting for salvaged material from the producer, gets some undesirable and unusual materials. The value of secondary metals and the importance of their recovery has increased in recent years and it is no longer sufficient to recover the base metal only, such as copper from copper-bearing material, but it is essential that other elements present be recovered and converted into useful form. This paper will deal not with the smelting and refining or separation of impurities from secondary metals but an attempt will be made to show the increased value of metal scrap when properly segregated and in a less contaminated condition. There are five principal reasons for contamination in secondary metals: New and unusual alloys, productive methods,

Jan 1, 1928

Jan 1, 1938

Jan 1, 1917

By E. C. Wright

THIS paper describes some properties of steels in the composition range 0.10 to 0.30 per cent carbon and 1 to 7 per cent chromium. It is well known that some steels of this type develop high tensile strengths upon receiving comparatively simple heat treatments, such as ordinary air cooling from appropriate temperatures, with "or without subsequent tempering treatments. These high strengths are frequently associated with unusual toughness as measured by the Izod or Charpy impact test. The chromium content, in addition to imparting the above properties, enhances the resistance to corrosion and improves the strength and oxida-tion resistance at elevated temperatures. Moreover, these steels have good forging and fabricating properties, as evidenced by the fact that several thousand tons of seamless tubing have been made during the past five years from steels containing 0.10 to 0.25 per cent carbon and 5 per cent chromium.

Jan 1, 1933

By R. J. Lutton

Basic features occurring on tensile fracture surfaces in rock are hackle marks, steps, and rib marks. Rib marks define the leading edge of the fracture and indicate that it was free of irregularities. In turn, fractures characterized by these features are believed to have propagated elastically and to be truly brittle. On the other hand, most fractures in rock exhibit hackle marks and steps in a plumose arrangement, indicating a ductile fracture process. Accordingly, the edge of the fracture apparently advances by extending en echelon fingers, each of which is in turn a small plumose fracture. Plastic-like deformation takes place in this zone prior to complete rupture. Some of the propagation is directed sideways and some shearing also occurs in this direction. Such lateral movement contributes little to forward propagation and may make this process particularly sensitive to load rate and duration and help account for greater fracture strengths of materials under dynamic loads.

Jan 1, 1971