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By P. V. Martin

SHORTLY after the middle of the nineteenth century, the invention of the regenerative open-hearth furnace and the development of the Bes-semer process stimulated a, rate of steel production whose magnitude created an unprecedented demand for pig iron. Revolutionary improvements in furnace design, auxiliary equipment, and operating technique enabled the blast furnace to keep abreast of the constantly increasing requirements of the steel mill. The development of improved blowing equipment, more adequate facilities for material handling, and particularly the general use of anthracite and coke to replace the physically weaker charcoal, led to a rapid expansion in both the height and volume of furnaces. Beyond a doubt,, however, the greatest single factor in blast-furnace improvement at this time was the use of the higher blast temperatures made available by the replacement of the recuperative iron pipe stoves by the regenerative Cowper brick stove. The increased blast tempera-ture not only resulted in greater output but also reduced fuel consumption far more than could be explained by the additional heat content of the blast. The progress of iron manufacturing was thus largely mechanical and thermal. Little attention was given tile chemistry of the process until the publication of the investigations of Sir Lowthian Bell.1 Bell's pains-taking experiments and investigations gave to the blast-furnace man his first real scientific conception of blast-furnace chemistry. Bell's recog-nition of the dual function of the carbon, the technical importance of reversible reactions and chemical equilibria, and his conception of the degree of oxidation of the carbon as shown by the analysis of the outgoing gases as a criterion of furnace efficiency, laid the foundation upon which has since been erected the structure of blast-furnace theory.

Jan 1, 1939

By W. H. Newhouse

During the past few years the writer has been impressed by the close relation of many epigenetic orebodies with anticlinal structures. In the literature on ore deposits there is occasional mention that an oreshoot or district is on an anticline, but in most of the descriptions no weight or significance is attached to the relation, and usually the fact is concealed in a mass of structural detail. A few writers have stressed the relationship in a few districts or on a certain type of deposit. Church, Spurr, Butler, Stahl and Schuette have called attention to certain features, but the general extent of such a correlation has not been made known in any publication that the author has seen. A recent article1 on the localization of ore deposits, by well-known geologists, does not consider this common association. The author has seen in the field a number of the structural features described, and in addition has made a fairly complete review of the literature. This paper presents enough of the examples found to show the frequency of the relation to anticlines, and since only a few deposits on synclines are known, all of these of any importance of which the writer knows are mentioned. With certain qualifications which are discussed later, epigenetic ore deposits of replacement or vein type are mostly found where local upwarps of the earth's crust have taken place. Where formations antedating the ore deposits are present in the proper attitude to demonstrate vertical warping (i. e., more or less horizontal beds) the structural feature on which a mineral district, or mineralized area is located is almost always anticlinal, or domelike in nature. Some or even most of the ore deposits in a given district may be on the flanks of the upwarp, but few major districts are located definitely on downwarped areas. Synclinal basins within certain limits of size appear to be unfavorable to the type of fracturing that admits ore-bearing solutions. Replacement orebodies frequently are localized in small anticlines or domes, the size of the anticline or roll often being more or less commensurate with that of the enclosed oreshoot. This feature certainly ranks

Jan 1, 1931

By Richard F. Moe

INTEREST in developing White Pine, considered since 1942, was renewed by the Korean conflict and its shortage of domestic sources of copper. In view of this Morris F. La Croix, president of Copper Range Co. of Boston, and of its wholly owned subsidiary, White Pine Copper Co., worked an agreement out with Government officials. Essentially the contract called for a construction loan of $57,185,000 at 5 pct interest, with $13 million additional supplied by Copper Range. Defense Materials Procurement Agency contracted for 243,750 tons of copper from the first 275,000 tons produced, at a base price of 25.5& per lb, the contract to expire Dec. 31, 1961.

Jan 4, 1954

By S. Usui, I. Matsuoka, H. Sasaki, J. Shimoiizaka

Depression of galena by sulfite or chromate ion in xanthate flotation was investigated by means of adsorption measurements, electron diffraction and flotation tests. Flotation of galena was depressed by sulfite ion only when galena had been oxidized; no depression took place with unoxidized clean galena. A similar behavior was found when chromate ion was used as a depressant, with the exception that the chromate ion depressed unoxidized clean galena around neutral pH. Depression was attained with galena on which xanthate still remained in appreciable amounts, indicating that the depression is not due to a decrease in xanthate adsorption. The galena surface produced sparingly soluble films under conditions in which depression of galena took place. These films were identified by electron diffraction as lead sulfite and lead chromate on oxidized galena and as chromic oxide on unoxidized clean galena. These observations in conjunction with contact angle measurements, indicate that the depressing action of sulfite or chromate ion arises primarily from film deposition resulting from the reaction between depressants and the galena surface. The thickness of the film was analyzed by means of electrochemical polarization.

Jan 1, 1976

By R. C. Edwards, T. G. Kirkland, Will Mitchell

A scrubber of new design has been invented for the beneficiation of glass and chemical sands. The machine is described and its capacity and metallurgical efficiency compared with the performance of other sand cleaning devices. THREE years ago, when the Process Research Laboratory at Allis-Chalmers Manufacturing Co. sought a remedy for the increasing cost of disposing of great quantities of spent sands from foundries, R. C. Edwards developed a continuous inclined paddle scrubber which removed a substantial amount of the charred coatings from the grains with a surprisingly small amount of degradation of the sand itself.' The satisfactory results obtained on foundry sand, using this piece of equipment in conjunction with classification, suggested that a similar procedure could probably be applied to the cleaning of other sands, such as those required by the glass and chemical industries. This paper describes the flowsheet and the results of tests performed on impure natural sands. The four materials tested were silica sands obtained from widely separated geographical areas. Three of the sands tested contained various amounts of iron oxide and the fourth an excessive amount of calcareous bonding material. The iron oxide was present predominantly in the form of grain coatings, which were scuffed by the paddle scrubber, and in all cases a product was manufactured which would meet one of the sets of specifications imposed by the glass industry.' The Edwards paddle scrubber used in these tests consists of a rubber-lined steel cylinder 18 in. in diam and 48 in. long, mounted on a frame so that its slope can be varied 5" to 35" from horizontal. This variable slope permits controlled flow of material through the machine. Rubber paddles rotate inside the cylinder and are secured to a center shaft 2 in. square, which extends through the entire length and is turned at both ends so that it can be supported by sleeve bearings centrally fixed in the end plates of the shell. At the upper or feed end it extends through the bearing on the end plate into a sheave, to which the motor drive is connected by means of Texrope transmission. The four sets of paddles mounted on the shaft, two in each set, are made of rubber belting, 1/4 in. thick, 9 in. wide, and 16 in. long. The two paddles in each set are secured on opposite sides of the square shaft, but in the same longitudinal position along the shaft axis. In other words, the two paddles in the set operate 180" apart. Each successive set is mounted 90" from the preceding one. One end of each paddle is bolted to the square shaft and the other weighted by a steel bar, lx1 1hx9 in. long, which is attached about Yz in. from the outer tip of the paddle. By centrifugal force at proper shaft speed, these weights force the paddle surface to rub smoothly against the rubber lining of the cylinder. During operation, the sand forces its way between the paddle face and the surface of the cylinder, providing the necessary abrading action as the pulp flows by gravity down the length of the cylinder. The capacity of the machine is limited by the amount and the hardness of the coating material and by the quality of product desired. The degree of scrubbing is governed by the retention time in the scrubber, which in turn may be changed by varying the feed rate, water content of the feed, and

Jan 1, 1953

By R. C. Edwards, Will Mitchell, T. G. Kirkland

A scrubber of new design has been invented for the beneficiation of glass and chemical sands. The machine is described and its capacity and metallurgical efficiency compared with the performance of other sand cleaning devices. THREE years ago, when the Process Research Laboratory at Allis-Chalmers Manufacturing Co. sought a remedy for the increasing cost of disposing of great quantities of spent sands from foundries, R. C. Edwards developed a continuous inclined paddle scrubber which removed a substantial amount of the charred coatings from the grains with a surprisingly small amount of degradation of the sand itself.' The satisfactory results obtained on foundry sand, using this piece of equipment in conjunction with classification, suggested that a similar procedure could probably be applied to the cleaning of other sands, such as those required by the glass and chemical industries. This paper describes the flowsheet and the results of tests performed on impure natural sands. The four materials tested were silica sands obtained from widely separated geographical areas. Three of the sands tested contained various amounts of iron oxide and the fourth an excessive amount of calcareous bonding material. The iron oxide was present predominantly in the form of grain coatings, which were scuffed by the paddle scrubber, and in all cases a product was manufactured which would meet one of the sets of specifications imposed by the glass industry.' The Edwards paddle scrubber used in these tests consists of a rubber-lined steel cylinder 18 in. in diam and 48 in. long, mounted on a frame so that its slope can be varied 5" to 35" from horizontal. This variable slope permits controlled flow of material through the machine. Rubber paddles rotate inside the cylinder and are secured to a center shaft 2 in. square, which extends through the entire length and is turned at both ends so that it can be supported by sleeve bearings centrally fixed in the end plates of the shell. At the upper or feed end it extends through the bearing on the end plate into a sheave, to which the motor drive is connected by means of Texrope transmission. The four sets of paddles mounted on the shaft, two in each set, are made of rubber belting, 1/4 in. thick, 9 in. wide, and 16 in. long. The two paddles in each set are secured on opposite sides of the square shaft, but in the same longitudinal position along the shaft axis. In other words, the two paddles in the set operate 180" apart. Each successive set is mounted 90" from the preceding one. One end of each paddle is bolted to the square shaft and the other weighted by a steel bar, lx1 1hx9 in. long, which is attached about Yz in. from the outer tip of the paddle. By centrifugal force at proper shaft speed, these weights force the paddle surface to rub smoothly against the rubber lining of the cylinder. During operation, the sand forces its way between the paddle face and the surface of the cylinder, providing the necessary abrading action as the pulp flows by gravity down the length of the cylinder. The capacity of the machine is limited by the amount and the hardness of the coating material and by the quality of product desired. The degree of scrubbing is governed by the retention time in the scrubber, which in turn may be changed by varying the feed rate, water content of the feed, and

Jan 1, 1953

By R. W. Raymond

In my paper on " End-Lines and Side-Lines in the Mining Law," read at the New York meeting of February, 1889 (Trans., xvii., 787), I discussed certain points involving the rights of a locator, B, who had located and surveyed a piece of ground, X + Y, of which only Y was properly subject to location, X being already held by another claimant, and had applied for and received a patent, granting X + Y, " excepting and excluding X." The paper concluded with the following questions : " Is there any difference in effect between the grant to him of Y simply and the grant of X + Y, ' excepting and excluding X' ? Why should any mining locator stake out his boundaries upon another location, and thus appear to assert a claim which he immediately withdraws? What is the legal force of such boundaries, established upon the land of another?" After calling attention to the fact that the entrance upon another's land for such a purpose is a trespass, and the principle that no trespasser can create by his trespass any right which he would not have without it, I reserved to another occasion a review of the history of the absurd practice of imaginary boundaries for mining claims, and a discussion of their legal effect. This practice is founded, of course, in the regulations and decisions of the United States General Land Office. There is nothing in the Revised Statutes which hints at it. On the contrary, the terms of Section 2322, giving to a locator " the exclusive right of possession and enjoyment" of the surface of his claim, seems clearly to forbid the use of that surface for the boundary-stakes of another locator. But the Act of 1866, though it provided for the issue of patents upon payment to the Government of so much per acre, and really by implication (as I have always believed) involved the absolute grant of the surface, was not so construed by the courts generally, or by the Land Office. Surveys were laid one over another in inextricable confusion, and the United States sold at $5 per acre the

Jan 1, 1890

By E. D. Glass, R. C. Hessing

The volume of gas in storage reservoirs may be compuled from estimates of hydrocarbon pore volume and gas density. However, both are dificult 10 estimate accurrately. Further, no adequate method has been presented for estimating reservoir performance during operation for Volumetric gas-storage reservoirs. Normally, gas-storage reservoirs exhibit small pressure gradients in the area conr(zilliitg the storage wells, even under conditions of maximum injection or withdrawal. A zone of low permeability usally surrounds, and is in communication with, tile permeable zone which causes the storage reservoir to exhibit a definite pressure lag, as evidenced by lack of pressure stabilization after extended periods of shut-in. An analysis is presented for determining pore volume and gas in place, and for predicting future reservoir behavior of such reservoirs. The mathematical development is presented and a solution is shown for an operating storage reservoir. INTRODUCTION Depleted gas reservoirs arc often used for gas storage. The reservoir usually contains a permeable area in which numerous storage wells arc located. The permeable zone permits high deliverability and injectivity with relatively small pressure loss. However, pressure equilibrium may not be attained even after long periods of shut-in because of the fact that the permeable zone is in communication with an adjacent tight section. Most of these gas-storage reservoirs are sand lenses, such as ancient beaches or offshore bars. The areal geometry of these reservoirs is normally such that flow in the tight zone will be approximately linear, and the solutions presented here should apply. DISCUSSION For purposes of this paper, a gas-storage reservoir is considered to consist of a volume of permeable rock in communication with tight rock, all of which is surrounded by an impermeable barrier. Pressure gradients across the permeable zone are small due to low flow resistance and well density. Hence, the permeable zone is considered to be at a uniform pressure which is only a function of time as gas is injected or withdrawn. The tight zone is considered to be linear with uniform permeability and porosity, and the pressure in the tight zone is a function of both position and time. l'wo solutions for flow in this system are used to define the reservoir and determine its properties. The first solution is for an infinite linear tight zone in communication with the permeable zone. The expression for constant gas-withdrawal rate is Eqs. I and 2 ore superposed to account for varying rates of production or injection and are used to fit gas-storage field reservoir history. The solution for the infinite case, Eq. 1, is first applied to field data for early times following a shut-in period. Constants BDa and c are ohtained by a least-squares fit of pressure and rate data. After the pressure wave from gas injection or withdrawal reaches the external boundary of the tight zone, the infinite solution will no longer apply and pressure behavior should be more nearly represented by Eq. 2 for a gas reservoir in communication with a finite linear tight zone. The values of the constants found from curve-fitting Eq. 1 to the early time data may then be used in Eq. 2 that only the coefficient- L containing the unknown

By Bruce W. Gonser, A. U. Seybolt

A few copper-zinc-hasp alloys mppt die-casting requirements reasonably well, although improvements are desired. Aluminum bronzes, high-tin bronzes and some copper-nickel-zinc alloys can be die-cast, according to Herb,' but seldom are because of such factors as higher melting ranges and greater cost than certain of the brasses. Fox2 has summarized the copper-base die-casting alloys that were in commercial use in 1937 and has given the effects of different alloying constituents. Table 1 gives some of the properties of these alloys as reported by Fox. a Properties reported by Fox.2 b Trade name of Brastil, Doehler Die Casting Co., similar to Webert Alloy,34 American Brass Co., and Tombasil Alloy,5 Ajax Metal Co. e Trade name Tinicosil, Titan Metal Manufacturing Co. Melting point (liquidus) of the yellow brass is given by Herb1 as 1650" F., of the high-silicon Brastil (with 4.5 to 5 per cent Si) as 1600" F., and of the nickel silver as 1675" F. d Criterion not stated.

Jan 1, 1940

By A. U. Seybolt, Bruce W. Gonser

A few copper-zinc-hasp alloys mppt die-casting requirements reasonably well, although improvements are desired. Aluminum bronzes, high-tin bronzes and some copper-nickel-zinc alloys can be die-cast, according to Herb,' but seldom are because of such factors as higher melting ranges and greater cost than certain of the brasses. Fox2 has summarized the copper-base die-casting alloys that were in commercial use in 1937 and has given the effects of different alloying constituents. Table 1 gives some of the properties of these alloys as reported by Fox. a Properties reported by Fox.2 b Trade name of Brastil, Doehler Die Casting Co., similar to Webert Alloy,34 American Brass Co., and Tombasil Alloy,5 Ajax Metal Co. e Trade name Tinicosil, Titan Metal Manufacturing Co. Melting point (liquidus) of the yellow brass is given by Herb1 as 1650" F., of the high-silicon Brastil (with 4.5 to 5 per cent Si) as 1600" F., and of the nickel silver as 1675" F. d Criterion not stated.

Jan 1, 1940

By Henry D. Hibbard, Edward L. Ford

The process of making washed metal now followed is in principle that described by Holley before this Institute in 1879, as the Krupp washing process. Sir Lowthian Bell also experimented extensively in England during 1877 and 1878 on refining iron and joined his interest with Krupp, the process being often referred to as the Bell-Krupp process. The only plant in this country now operating this process is that of the Brier Hill Steel Co., Youngstown, Ohio. This process may be considered as the sole survivor of the numerous methods conceived for refining crude iron, when the removal of phosphorus from steel-making material was the great desideratum affecting large districts. The east coast of England and all northern Germany, the homes of Bell and Krupp, respectively, could at that time make steel only from imported ores. These processes were in use or in various stages of development 40 years ago and all except the Bell-Krupp received their quietus from the development of the basic steel processes, both pneumatic and open hearth. The aim of the early refining processes was, first, the removal of the silicon, which could be done on a sand bottom, and later, the removal of the phosphorus, requiring a bottom which would give or permit a basic slag. The incidental advantages of increased yield and small fuel consumption were not generally recognized or considered; the aim of the later operations was the saving of the difference in value between low and high phosphorus irons, as well as hastening the removal of the metalloids. The chemistry of the washing process follows in part that of the puddling process, and indeed washing might be considered as the first half of puddling, since all the non-ferrous elements of the crude iron, except the carbon, are eliminated and the iron is maintained molten until cast. In puddling, the iron loses its carbon as well, and because of that, its fusion point rises above the hearth temperature; it freezes into a pasty malleable form, and is worked at once by squeezer, hammer, or rolls. Since Holley's paper, important improvements have been made from time to time in both plants and methods for washing iron, and the

Jan 1, 1916

By J. D. Alexander, W. L. Martin, J. N. Dew

This paper presents data obtained using a flood-pot technique to determine the fuel available and the corresponding theoretical air requirements for in situ combustion of crude oils. Since the technique is relatively quick and easy, it is a practical and convenient tool for evaluating reservoirs as fireflood prospects. It is also a research tool which facilitates systematic study of the variables affecting fuel availability and corresponding air requirements. The understanding of these variables is of prime importance to those concerned with the technical and economic development of in situ combustion as an oil-recovery process. The experimental results show conclusively that the fuel available for in situ combustion is not a constant but, rather, varies with crude-oil characteristics, porous-medium type, oil saturation, air flux and time-temperature relationships. Thus, the fuel availability for specified field applications should be determined using actual reservoir crude and core material and the process conditions expected during in situ combustion in the reservoir. INTRODUCTION In situ combustion is a thermal process for recovering crude oil from reservoirs. The thermal energy released during the combustion of a small amount of the oil in place aids in the displacement of the remaining oil. Numerous articles have been published describing the in situ combustion process giving detailed results of laboratory and field experiments.10 In order to engineer an in situ combustion project, a number of important factors must be considered and determined. These factors include: (1) the amount of fuel consumed per unit of reservoir volume swept by the combustion zone, (2) the composition of the fuel consumed, (3) the amount of air required to consume this fuel, (4) the portion of the reservoir swept by the combustion zone, (5) the appropriate air-injection rates and pressures, (6) the amount of oil that will be recovered, (7) the rate of oil production and (8) the operating costs. Nelson and McNiell1 recently have described a procedure which utilizes laboratory combustion-tube data as a basis for the calculation of some of these design factors. Various authors have attempted to describe the in situ combustion process mathematically, and considerable progress has been made. Analytical solutions to the problem of heat transfer from a moving combustion front have been obtained for linear and radial systems."-' All of the published results involve the assumptions that: (1) fuel concentration is constant throughout the reservoir, or that fuel concentration is inversely proportional to the velocity of the front for a given rate of oxygen consumption; and (2) the fuel reacts instantaneously with injected oxygen, while liberating a constant amount of heat per unit weight of fuel at all temperatures. It seems both desirable and reasonable to test the validity of these assumptions experimentally. This paper presents laboratory data which were obtained by means of a "fire flood-pot" method for determining fuel availability and composition, and the corresponding theoretical air requirements for in situ combustion of crude oils under variable conditions. The mechanics of the method are similar to a conventional tube-run experiment.' The important differences involve the size of the reservoir model used and the method for providing the experimental environment. The new method subjects conventionally-sized core samples or unconsolidated sands to a programmed environmental sequence similar to that experienced by a similar volume of rock during the approach and passage of a combustion front in a long tube or in an oil reservoir undergoing in situ combustion. Restored-state samples can also be used. The small samples and relatively simple techniques involved allow an experiment to be set up, run and calculated in about three 8-hour days. This is a considerable improvement over long-combustion-tube techniques which can require several days to run and several more work days to set up and calculate. All the runs presented were run at 40-psig injection pressure. Pressure was not considered as a variable for these experiments, since we previously had found that it had only a small effect on fuel availability up to 600 psig.APPARATUS AND MATERIALS APPARATUS The fire flood-pot apparatus consists of a consolidated

By J. S. Osoba, J. W. Graham, P. H. Monaghan

Of the many factors which affect the productivity of hydraudically fractured wells, the wettability of the propping sand has received little attention in the pas/. This paper shows that the wettability of the propping sand is an important factor which shorcltl not he overlooked. An analysis of relative permeability data shows that fractures packed with water-wet sand should be more permeable to oil than are fracturer packed with oil-wet sand. Laboratory results verify this conclusion. Cnlculations show that higher permeability to oil in the fracture should provide higher well productivity. A method is presented which ensures that the propping sand in an induced fracture is water-we1 even though oil is used as the fracturing fluid. The rnethod has been used in more than 150 field jobs: the field resrrlts are discussed briefly. The fluidized nature of water-wet sand in oil has giver1 unexpected benefits. This characteristic of water-wet sand and how it has been used advantageously in field operations are discussed. INTRODUCTION Hydraulic fracturing of subsurface strata to increase the productivity of oil and gas wells has been practiced for about 10 years. Today, fracturing is used more often than any other method of well stimulation. Basically, the process consists of breaking down (fracturing) a subsurface formation with pressure applied by means of a carrier fluid, usually oil or water, and propping the induced fractures apart by means of an agent, usually sand. suspended in the carrier fluid. Currently about 68 per cent of all fracturing is done with a simple mixture of refined oil or lease crude oil and sand'. The research of other investigators has suggested that dry sand is rendered oil-wet when it is contracted with certain types of crude or refined oils.' Hence, it may be expected that some fracturing operations employing an oil as the carrier for sand leave fractures packed with oil-wet sand. Conversely, those operations which employ water as the carrier for the sand probably leave the fractures packed with water-wet sand. Since the permeability of a sand-packed fracture to a mixture of oil and water is dependent upon the wettability of the fracturing (frac) sand, research was undertaken to determine to what extent the wettability condition (water-wet or oil-wet) controls fracture permeability which, in turn, affects well productivity. Additional research was directed toward the development of a method for obtaining the desired fracture wettability. In this report both theoretical and experimental evidence is presented to show the desirability of employing water-wet sand in fracturing operations. A method to obtain water-wet sand is discussed, and field results are reviewed briefly. DEPENDENCE OF WELL PRODUCTIVITY ON FRACTURE WETTABILITY To determine the dependence of well productivity on the wettability of the frac sand, it is necessary to know, first, the effect of fracture wettability on fracture permeability and, second, the effect of fracture permeability on well productivity. The relationship of these variables is considered separately in the order indicated. Effect of Wettability on Permeability Fig. 1 shows relative permeability relations for 20-30 mesh Ottawa sand. Inspection of these curves reveals that the relative permeability to oil when a small amount of water accompanies the flow is considerably higher when water rather than oil is the wetting phase. For

By T. H. Aldrich

The Aldrich Mining Go. holds under lease from the Illinois Central R. R. Co. about 14,000 acres, in the east half of Township 12, Range 12 W., in Marion county, Alabama, and owns other lands, of which about 1,000 acres adjoin this leased tract, making a total area of about 15,000 acres, all of which is underlain by the coal-seam upon which the company is operating. This seam is nearly horizontal; and a ravine, diagonally crossing the tract, exposes the outcrop on either side for about 2 miles. The territory has been so divided that nearly the whole of it can be worked out by two collieries. The mines at Brilliant were opened in the fall of 1898, and shipments began in the following spring. The original plan was to furnish steam-coal for locomotives to the Illinois Central R. R. Co.; and upon this expectation the investment of capital was made. The field was entirely new; and the softness of the coal at the outcrop induced the belief that it could be very cheaply mined. A contract for the delivery of a large quantity of coal to the railroad was accordingly executed. But with the advance of' the entries to increasing distances from the outcrop, the coal proved so hard that it could no longer be drilled with a breast-auger; and the expense of mining became so great that the contract for cheap steam-coal had to be canceled. It became evident that the work must be done with machinery and explosives, if it could be profitably done at all. On the other hand, the excellent quality of this coal opened, at the same time, a possible market not specially contemplated at the outset—namely, that of a first-rate coal for domestic and general uses. Since no other deposit of such coal was known to exist on the line of the Illinois Central, or any other railroad

Jan 1, 1907

By N. Tiner

THE mechanical properties of magnesium-alloy castings are greatly improved by grain refinement, and at present considerable attention is being paid to methods of obtaining fine-grained castings. One method of achieving this end is the use of proper melting and superheating techniques. These have been employed commercially to a great extent, but no comprehensive study of the subject appears to have been published at present. Numerous investigations found in the literature include some reference to superheating techniques, 1-4 and Achenbach, Nipper and Piwowarsky,5 based principally on thermal analysis, ascribe the grain-refining action of superheating to the influence of solid foreign particles or dissolved gases present in the melt upon the course of crystallization. The primary purpose of this paper is to present the principal facts concerning the effect of superheating on grain size of magnesium alloys. Attempts are also made to explain the experimental results in terms of a general hypothesis. The investigations are limited chiefly to common commercial casting alloys. In order to carry on this work, it was necessary to determine the factors influencing grain size and to develop a proper technique for the preparation of samples. The preliminary tests made by the author indicated that the grain size of magnesium alloys resulting from the solidification of a melt is determined by alloy composition, presence of impurities, rate of cooling during solidification, thermal history of the melt and to some extent the structure of the charge used. The rate of cooling is in turn dependent upon the mass of the melt, pouring temperature, and dimensions, properties and temperature of the mold into which the melt is poured. The final grain size of the alloys is still further modified by heat-treatment subsequent to casting. It is not within the scope of the present paper to discuss all of these factors, and it would suffice to note here that when equal amounts of magnesium alloys are prepared from the same alloying materials, melted in graphite crucibles under the same thermal conditions, then cast into graphite molds at a constant temperature, the .resultant solids have the same grain size. By maintaining all other factors constant, it is thus possible to vary thermal conditions of a melt and to examine the grain size of resultant castings. PREPARATION OF SAMPLES AND GRAIN-SIZE TESTING The alloys investigated in this paper were taken from ingots made by Permanente Metals Corporation or prepared by the author with pure carbothermic magnesium and necessary alloying elements. Melting was carried out under a flux in a graphite crucible heated uniformly by an

Jan 1, 1945

By C. Perez-Rosales

A simplified method for evaluating specific surface of porous media is described. The theory takes as its point of departure a previous statistical method. Due to its simplicity, it is considered that the proposed method has certain advantages over methods currently used. By making some simplifications, the procedure for estimating specific surface is reduced to superposing, on an enlarged reproduction of a section of the sample to be analyzed, an evenly spaced grid and counting the number of intersections of the grid lines with the perimeter of pores. An indirect test of the theory is presented and the advantages of the method are discussed. INTRODUCTION The specific surface of a porous medium, defined as the surface area of the pores per unit bulk volume, is an important parameter with regard to flow of fluids through porous materials. In particular, it has long been recognized that specific surface is closely related to permeability. Since the internal surface of any porous material is extremely complex, the measurement of specific surface can only be accomplished by indirect means. It is considered that the best method' in current use for determining specific surface is the statistical method of Chalkley, Cornfield and Parka who originally applied it for estimating volume-surface ratios of morphologic components, such as cells or nuclei. This method will be outlined later. A method which has been used extensively in determining specific surface is based on the adsorption of a vapor by the internal surface of porous media. However, this method does not yield the surface pertinent to fluid flow, since it includes the tiny molecular interstices which do not influence the permeability of the porous material.' This method has been employed by Brooks and Purcell measure internal surface area of sedimentary rocks. The Kozeny equation, which relates the specific surface to the permeability of a porous medium, has found wide use in determination of specific surface. However, the KOzeny equation is not strictly correct. Large discrepancies have been found between theory and experiments.' Consequently. the specific surface estimated by this method is subject to serious uncertainties. Finally, there are other methods for specific surface measurements which are based upon a variety of physical and chemical properties: the heat conduction by a gas, ionic adsorption phenomena and direct chemical reactions of the surface with other substances. This paper describes a simplified statistical method for determining specific surface of porous materials. It is considered that, due to its simplicity, it has certain advantages over the methods presently used. For its validity, it is required that the porous structure of the material under study be of a spatially random nature. This is not a serious limitation since the naturally occurring porous media have this characteristic. THEORY The method proposed in this paper takes as its point of departure the interesting result obtained by Chalkley et al The method shows that if a line of length r is dropped repeatedly at random over a section of a porous medium, and counts are made of the number of times the two end points fall within pore areas (denoted by h for "hits") and the number of times the line intersects the perimeter of pores (denoted by c for "cuts"), then in a very large number of throws where S is the internal surface of the sample (surface of pores) and V, the volume of the pores (Fig. 1). Since the specific surface S, and the porosity 4 are given, respectively, by S. = Sl V, and 4 = V,l V,, where V, is the total volume of the sample, it follows from Eq. 1

By Ian Wark

SODIUM sulfide is used extensively to increase the recovery of oxidized copper and lead minerals by flotation, particularly when using xanthates as collectors. It is generally assumed that the sodium sulfide converts a film of the oxidized mineral to the sulfide, and that the xanthate, while not a very effective collector for the oxidized minerals, is a good collector for the sulfide. On the other hand, Taggart and his collaborators' claim that unless sulfide minerals are oxidized they cannot adsorb xanthates and do not float. Gaudin2 states that amyl xanthate, used in conjunction with sodium sulfide, gives better results than ethyl xanthate. Rabone3 and Mayer-Schranz4 agree that excess of sulfide functions as a depressant. Owing to the greater solubilities of the oxidized minerals than of the sulfides, the consumption of sodium sulfide is greater than that of most other flotation reagents, up to 10 lb. per ton of ore being used in some plants. Luyken and Bierbrauer5 recommend a water washing to remove soluble heavy metal salts; by this means sulfide consumption may be reduced. It was desirable to determine the limits of the sulfide concentrations between which contact is possible at surfaces of anglesite and cerussite in xanthate solutions. Similar determinations were desirable for the sulfide minerals with which the oxidized minerals are usually associated, since conditions should be chosen, if possible, so that the two types of mineral will float together. Because of the formation, especially in acid solutions, of hydrogen sulfide and of the hydrosulfide ion (HS-), the permissible limits of sulfide addition are obviously dependent upon the pH value. Sphalerite responds to ethyl xanthate only in the presence of an activator; for example, copper sulfate. It was necessary, therefore, to determine whether sodium sulfide interferes with the activation of sphalerite by copper sulfate. The combined effect of sulfide and copper sulfate was determined also for galena, chalcopyrite and pyrite.

Jan 1, 1936

By E. R. Buchanan, R. E. Reed-Hill

Cylindrical magnesium single crystals were deformed in torsion. The axis of torsion was the basal pole. Five crystals were deformed to different strains between 0.08 and 1.03 and then sectioned in order to determine their dislocation densities using the transmission electron microscope. The work hardening rate of all specimens was at least an order of magnitude higher than that normally associated with easy glide in a tension test and comparable to that obserzed in stage B of a tension test. The correspondence between stage B in a tension test and the initial stages of a torsion test is believed to result from the fact that in both cases deformation occurs in a structure containing roughly equivalent densities of the dislocations associated with the three basal slip vectors. THERE are three basic ways of changing the shape of a crystal using slip dislocations. The crystal can be sheared along a slip direction in a slip plane; it can be bent about an axis in the slip plane normal to the slip direction; and, if the slip plane contains multiple slip directions, it can be twisted or rotated about the slip plane normal. Of the three processes, generally known as translational, flexural, and rotational slip, only rotational slip has not been extensively investigated. The object of the present research was to obtain basic information about this phase of crystalline plasticity. This paper is concerned with some aspects of the stress-strain curves obtained by twisting magnesium crystals about their basal poles. Magnesium was selected for four reasons. One, its recovery rate at room temperature is relatively low. Two, single crystals may be easily grown. Three, at room temperature the critical resolved shear stress for basal slip is about two orders of magnitude lower than that for nonbasal slip, so that rotational slip might be expected to occur primarily by basal slip. Finally, relationships between flow stress, shear strain, and dislocation density have been determined for tensile deformation of magnesium crystals,' thereby providing a basis of comparison for the torsional results. EXPERIMENTAL PROCEDURES Crystals were grown from 0.5 in. diam extruded sublimed magnesium rod furnished by the Dow Chemical Co. who reported that it contained in weight percent less than 0.0003 Al, 0.01 Ca, 0.01 Cu, 0.0012 Fe, 0.001 Mn, 0.0005 Ni, 0.003 Pb, 0.001 Si, 0.01 Sn, and 0.02 Zn, with the balance magnesium. All crystals were grown in a dried argon atmosphere using Jill-son's2 modified Bridgman technique. Two different methods were used to obtain crystals with the basal plane normal to the specimen axis. These included direct growth from seeds of the proper orientation, and spark machining (trepanning) of 0.5 in. diam cylinders from larger (1.5 in. diam) randomly grown crystals. The crystals thus produced were polished in a 20 pct HC1 water solution and then etched in a 1 pct HC1 water solution to develop etch pits lying in rows parallel to the basal plane trace. The crystals were then revolved about their axes on the stage of a low-powered microscope. Torsion specimens were prepared only from those crystals whose axes were normal to the rows of etch pits. It is estimated that this simple orientation method was accurate to about 51 deg. 1.625 in. long cylinders were next cut from these selected crystals and then acid machined in a 20 pct HC1 water solution into torsion specimens with a 1 in. long by 0.30 in. diam reduced gage section. Following this, they were annealed in air at 400°C and furnace cooled to room temperature. The specimens were given a final polish in a 10 pct HC1 water solution, rinsed in ethanol, dried, and cemented into brass grips with an epoxy resin. In addition to the torsion specimens, several tensile specimens with their basal planes at 45 deg to the stress axis were also prepared with similar dimensions except that the gage sections were increased to 4 in. in length. The torsion specimens were tested in the apparatus

Jan 1, 1970

By P. H. Brace, N. A. Ziegler

The study of the relations between gases and metals is one of pcren-nial interest to all who are connected with the production of high-grade metallurgical products. The data reported here are the outcome of work of which the object is to determine the effects of dissolved gases upon the properties of metals and to gain a more detailed knowledge of the reactions between gases and molten metals, particularly iron, under definitely controlled conditions. We have attempted to reduce our margin of error by dealing with relatively large quantities of metal, from 4 to 13 Ih. (2 to 6 kg.), and keeping the ratio of refractories to metal as small as practicable. The ingots produced are large enough to provide adequate material for making determinations of magnetic and other physical properties. In choosing the bell-jar type of furnace we were influenced by the results of considerable experimentation along the same general line which indicated that, for the scale on which we were to work, it was important to have the furnace structure independent of the vacuum enclosure. The use of a bell-jar surrounding the entire furnace accomplishes this and also gives great freedom of observation during operation and ready accessibility for the replacements which are necessary after each run. Our choice of analytical method was made in the light of the results secured by H. M. Ryder, who used a method similar in principle for the analysis of very small quantities of gas extracted from strips of metal heated electrically in high vacuum. We have presented some selected preliminary experirnental data as being illustrative of the quantity and nature of the gases which occur in iron of different origins, but do not urgc any hypothesis at this time. The Furnace Our furnace may be described as "a high-frequency induction furnacc of the bell-jar type." It is similar in a general way to that described by Cain and Peterson1 though we have introduced certain refinements of

By William E. Newman

When Hugh Lee Pattinson discovered, in 1829, that the crystals formed during the slow cooling of molten lead were poorer, and the remaining liquid richer in silver, than the original lead, an important step was made in the metallurgy of this metal. Being the first process applicable to the desilverization of low-grade lead bullion, it soon found its way into all European countries having such a product to treat, thereby effecting the saving of many ounces of silver annually which previously had been thrown away. The old hand process was expensive, as viewed from the standpoint of more modern methods; the labor was great and the tonnage was small, but on the other hand the results were fairly satisfactory. This process flourished for some time after the introduction of the cheaper Parkes process in 1852 and it is still in use in a few European smelteries. Only one notable improvement was made on the original process, that of Luce and Rozan at Marseilles, France. It consisted in the application of steam for stirring and the tapping of one-third of the liquid lead, through perforated plates covering the tap holes flush with the bottom of the kettle, thus leaving two-thirds in the form of crystals in the original kettle. This modification considerably lowered the operating costs as it permitted of much larger kettles, an increased tonnage and eliminated much of the slow, hard labor of the hand process. The Luce and Rozan process has persisted in its original form to the present day. Stephen Tredinnick, English born, spent most of his years around the Luce and Rozan plants at Marseilles and elsewhere in Europe, coming later to Eureka, Nev., in 1878, to operate the Luce and Rozan plant at that point. Mr. Tredinnick was a competent Luce and Rozan operator and being devoted to the process he firmly believed that with modifications the costs could be so lowered as eventually to supplant the Parkes process. Out of many schemes he decided that this could be accomplished by placing the Luce and Rozan kettles upon hydraulic rams so that each

Jan 1, 1918