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By W. A. Tiller

SEVERAL authors1-6 have shown that, during solidification from the melt, the direction of formation of substructure boundaries depends upon the direction of heat flow and the rate of solidification of the metal. The most prominent of these observations was that a preferred orientation developed during the solidification of the columnar zone of an ingot which for face-centered-cubic metals was the <100> direction. Previous explanations1-&apos; given to account for this preferred orientation and the other boundary phenomena are all based on the premise that the phenomena are characteristics of the pure element. However, recent experiments by Rosenberg and Tiller7 have demonstrated that the preferred orientation in pure lead is the <111> orientation, and that the heretofore observed <100> orientation is due to the effect of solute on the mode of solidification of the metal. Teghtsoonian and Chalmers,4 studying striation boundaries in tin, and Chalmers and Rutter,5 studying corrugation boundaries in tin, showed that these substructure boundaries were aligned parallel to the axis of heat flow for slow rates of growth, and that the alignment varied from this direction as a function of the rate of growth. to approach the den-drite direction at high rates. Chalmers,6 studying the direction of formation of a grain boundary separating two crystals of different orientation, showed that at slow growth rates the boundary is parallel to the axis of heat flow, while at higher speeds it will deviate from this direction, sloping into the crystal whose dendrite orientation departs the most from the axis of heat flow. It is this phenomenon that allows certain crystallites in the chill zone region of an ingot to encroach on their neighbors and ultimately produce the preferred orientation of the columnar zone of the ingot. Since the previous explanations of this preferred orientation are unable to account for the recent observations,&apos; a new mechanism will be considered. This will lead to an explanation of the other substructure boundary phenomena as well. Investigations by Graf,8 Billig,9 Rsenberg,10 and others have demonstrated in a striking fashion that crystal growth takes place by the deposition of individual layers oriented along the close-packed planes of the material considered. This lamellar or

Jan 1, 1958

By Thomas M. Drown

THE means relied on to attain uniformity in Bessemer steel may be enumerated as follows I. The appearance of the flame. II. The appearance of the slag. III. The spectrum of the flame. IV. Examination of the steel itself. At present, I wish briefly to bring forward a few considerations with reference to the last two mentioned, namely, the conditions favoring the employment of the spectroscope and examination of the steel. From the amount of careful investigation which has been devoted to the examination of the Bessemer flame by the spectroscope, both on the part of scientists and practical metallurgists, one might reasonably expect some results definite and satisfactory in their nature, first, as regards the nature of the flame, and second, as to the practical value of the spectroscope as a guide in conducting the process. We find, in fact, however, that uncertainty and confusion still exist. In Germany, where this subject has received the greatest attention, it is now very generally conceded that manganese is the cause of the well-known groups of dark bands that characterize the Bessemer spectrum. Nor is it easy to see how we can avoid accepting this conclusion, when Wedding and Von Lichtenfels have produced the manganese spectrum and found it to correspond closely with that shown by the Bessemer flame. But it is evident, on a moment&apos;s reflection, as Roscoe has recently brought forward, that manganese cannot be the only cause of the Bessemer spectrum, for we notice the characteristic bands quite as

Jan 1, 1873

By E. N. Cameron

GRAPHITE has been included in U. S. lists of strategic minerals since the problem of mineral deficiencies was revealed during World War I. Since 1918 the domestic graphite industry has led a precarious existence, and there has been much uncertainty as to the amounts of usable graphite of various grades that would be available from domestic sources in time of emergency. In 1950-1951 therefore, the writer, assisted by Paul L. Weis, undertook a review of domestic graphite sources for the U. S. Geological Survey.&apos; The conclusions of this study are presented here, with a discussion of some technologic and politico-economic factors bearing upon the problem. Uses of Graphite: Natural graphite as marketed exhibits a wide range of properties, which determine the uses to which it is put. The most essential uses are in the manufacture of crucibles and related refractory articles, in lubricants and packing materials, and in the manufacture of batteries, foundry facings, pencils, and carbon brushes. Numerous specifications covering the mineral in its various applications must be met by producers and processors of graphite. The problem of supply is therefore not simply one of procuring a sufficient total tonnage, but the more difficult problem of procuring enough of each different grade to meet foreseeable needs. The amount of graphite required by American industry is not large. Ordinarily only a few thousand tons of strategic grades are consumed annually, yet the elimination of this small tonnage would have serious effects in several industries. Strategic Graphite: Since World War I, 60 to 100 pct of the country&apos;s annual supply of graphite has been furnished from imports. At present, natural amorphous graphite for use in pencils and batteries is produced largely from American-owned mines in Mexico. Graphite for foundry facings is obtained from a number of sources. Neither grade is a serious problem. High purity graphite for carbon brushes and for pencil leads, however, is imported, largely from Ceylon, in the form of amorphous lump graphite. Most of the flake graphite used for crucibles and related refractory articles is likewise imported, largely from Madagascar, and much of the lubricant and packing grade graphite used by industry is obtained from the same source. The strateg&apos;ic grades of graphite are therefore amorphous lump of the Ceylon type, crucible flake, and flake suitable for lubricants and packing. Ceylon lump and Madagascar flake have for many years been accepted as standard by domestic consumers of graphite, and various essential manufacturing processes are geared to the use of graphite from these sources. Ceylon graphite as marketed is classified into several grades based on particle size and purity. Processing methods are said to be simple, but the products marketed are carefully graded and are consistent in their characteristics, an important matter to the consumer. Nearly all the graphite produced in Ceylon is from veins. Resources are reported to be large, labor is cheap, production costs are low, and world competition is slight—factors accounting for the commercial success of the graphite mining industry in Ceylon. Madagascar is reported to have deposits of the Ceylon type, but its output consists almost entirely of flake. Madagascar graphite as received in the U. S. is further processed by importing organizations, and a large number of grades are produced to meet industry requirements, especially those for crucible flake and for lubricant and packing grade flake. Madagascar crucible flake as marketed is noted for coarseness, uniformity, toughness, clean-

Jan 1, 1957

By L. E. Young

THE purpose of this paper is to start a discussion on: (1) methods of supporting the immediate roof, particularly of local areas of poor roof, during the mechanical loading of coal; (2) methods of increasing the rapidity of the movement of the mining faces so that, without the use of cribs, jacks, pack walls, and filling, there will be no danger to men, equipment,, and working places from the subsidence of the overlying strata. In the Pittsburgh district the application of mechanical loading devices in mines working in the Pittsburgh seam, has been retarded by the difficulties of holding and handling the draw slate. Normally the thickness of this slate averages about 8 in. but the hardness varies, and a cut of coal cannot always be loaded without placing posts or crossbars to support the slate. Locally, the slate may be thicker and special methods of support may be required. If crossbars are placed to hold the slate when the coal averages 5 ft. in thickness, the standard methods of transporting the coal cannot be followed, and the use of conveyors may be desirable. Very little information is available on the effect of increasing the rate of movement of advancing or retreating break lines or longwall faces. A few British publications have presented some data but all such data relate to longwall faces that have moved not more than 6 ft. a day. The most rapid rate of movement of longwall faces in Germany is 6 ft. per day. In the ordinary hand-loading mine in western Pennsylvania break lines on full retreat will move about 2 ft. per day. If loading machines are used under similar conditions the, rate of retreat may reach 4 ft. per day. In a mine where coal is loaded by hand on conveyors three shifts per day, the rate of retreat has ranged from 11 to 16 ft. per day, with an average of 13 ft. If mobile loading machines could be used to load on con-veyors on break lines, the rate of retreat should be increased substantially.

Jan 1, 1938

Section 67 Department of Conservation and Development, State of New Jersey, State House Annex, Trenton, N. J. H B Kummel, State Geologist For lists of publications, maps and geologic folios, address the above. Where price of postage is noted, in the following list of available publications on geology, the postage is only to New Jersey and

Jan 1, 1933

By B. H. Caudle, W. J. Bernard

Factors which influence the success or failure of a waterflood can seldom be determined in the laboratory. For this reason pilot waterfloods are initiated in a repreventative portion of the oil reservoir in question. For a pilot flood to predict quantitatively the recovery to be expected in a field-wide waterflood operation, the pilot area must behave as though it were confined (surrounded by similar areas). In this study, laboratory fluid-flow models were used to determine the simplest pilot pattern, for particular conditions of mobility ratio and initial gas saturation, that would behave as though it were confined. Pilot patterns studied ranged in complexity from a single inverted five-spot to a grouping of nine regular five-spots. Only the innermost producing well in each pattern was studied. Model results showed that the optimum number of wells in the pattern depends upon the oil-water mobility ratio and the expected oil-bank size. Unfavorable mobility ratios will, in general, require more wells in the pilot pattern than will favorable mobility ratios. Pilot patterns in reservoirs which contain a dispersed, flowable, free gas saturation will require fewer wells than for the under-saturated case. The single inverted five-spot pattern was found to be unsatisfactory for predicting behavior of fully developed waterfloods. In particular, it is possible that, in reservoirs which contain a flowable, dispersed gas phase, the oil bank will never be observed at the producers due to the large amounts of free gas which continue to be produced with the oil. INTRODUCTION One method which has been used to predict the performance of a waterflood is the pilot flood. The pilot waterflood is a flood which involves only a small cluster of the reservoir wells and is located in a small, representative portion of the reservoir. The object is that oil produced from the pilot can, in some way, be related to the oil recovery to be expected from a field-wide expansion of the waterflood. However, these field pilot waterfloods have often been unreliable in the prediction of oil recovery in a fully developed waterflood. This unreliability has also been demonstrated in several laboratory studies of pilot floods. Some of the investigators have shown that there are situations in which the pilot flood oil production is far too optimistic with respect to the oil recovery in the fully de- veloped flood. Others4-G have shown that the pilot results can also be pessimistic, especially if the pilot waterflood is initiated in an oil reservoir which has been depleted by primary recovery and is at very low pressure. The major reason for this unreliability of pilot water-floods is the migration of fluids into or out of the pilot area. By the well-known method of images, if straight lines can be drawn to represent vertical planes of symmetry in a porous medium which contains pressure sources and sinks (injectors and producers), then these lines are invariant streamlines, or lines across which there is no potential gradient, and therefore no flow. In an actual reservoir, these lines of symmetry can never be established exactly because of reservoir inhomogeneities and irregular reservoir boundaries. However, if the reservoir is relatively large and contains wells in repetitive patterns, these lines of symmetry are commonly assumed to exist for the pattern units sufficiently far removed from the reservoir boundary. Lines of symmetry for the five-spot injection pattern are shown in Fig. 1. Each five-spot unit in this figure can be considered confined with respect to flow across its boundary. In pilot floods this is not the case. The lines of symmetry for the pilot patterns investigated in this study are shown in Fig. 2. It is obvious that the fluid within these pilots is not confined and is therefore able to migrate into or out of the pilot area. Intuitively, one can see that, if more wells are added to the pilot, the innermost unit tends to behave more and more like the confined pattern. However, there is a practical limit to the number of wells which should be placed in the pilot. This limit is usually determined by economic factors. It was the purpose of this study to use laboratory fluid-flow models to determine which of the previously mentioned pilot patterns will force the innermost producing well to behave as it would in a fully developed waterflood. Since fluid migration is influenced by initial saturation conditions and the mobility ratio, these factors were included in the study. The ultimate objective of this study was to develop data which would allow the operator to choose a pilot pattern and operating conditions that will yield a production history which can be applied directly as an estimate of the performance of each production well of the fully developed waterflood. BASIS FOR THE STUDY The basic problem of field pilot floods is the migration of the reservoir fluids into or out of the pilot area. This problem has been the subject of previously reported model studies on pilot floods. These studies have been concerned mainly with the development of arbitrary "correction factors" to be applied to the simple, unconfined pilot systems such as the single five-spot. The correction factors were intended to adjust the production history of the un-

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318&apos; C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430&apos; F. (778" C.)

Jan 1, 1923

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318&apos; C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430&apos; F. (778" C.)

Jan 1, 1923

By I. R. M. Chatson

Radial layout&apos;s guiding principle is the grouping under one roof of the operating processes which require continuous supervision. Separate treatment sections are isolated by outside stockpiles fed with radiating conveyors. Hence the name "radial" layout. Many plants are designed with "linear" layout where successive operating stages are dotted like beads along a string of conveyors.

Jan 11, 1978

By I. Iwasaki, K. Adam

The oxidation behaviors of simple and complex chloride systems of copper, iron, nickel, cobalt, and manganese in a stream of oxygen were investigated using a thermogravimetric analysis technique. Their reaction mechanisms are discussed from stoichiometry, thermodynamic feasibility, and X-ray diffraction analysis of reaction products. The results are used to determine an optimum operating temperature of the selective oxidation step in a chlorination process for producing nonferrous metal chlorides, elemental sulfur, and ferric oxide from copper-nickel sulfide flotation concentrates.

Jan 1, 1985

By Valentin R. Garfias, C. O. Isakson

The production of oil in Mexico during 1929 was approximately 45,000,000 bbl., or 5,000,000 bbl. less than in 1928. The production of the fields near Tampico showed a decline of over 10,000,000 bbl. for both the light and heavy crudes, which was partly offset by an increase of over 5,000,000 bbl. in the production of the fields in the Isthmus of Tehuantepec. During 1929 the retrenchment policy followed by practically all the companies was continued and no material improvement should be expected until the unsatisfactory conditions that brought about this situation are remedied. A new administration has just assumed control in Mexico; it should remain in power for 6 years, and the progress of the oil industry during that time will depend primarily on the policy pursued by the new government with respect to oil development. Development During 1929, there were drilled 214 wells as compared with 371 in 1928 and 583 in 1927. The percentage of producers in 1929 was 47.2 as against 34 per cent. in 1928. The new wells did not show water as quickly as in 1928, particularly in the Cacalilao field, where the greatest number of producers was brought in, their average initial daily production being 380 bbl. The flush daily production per well in the Southern fields was 1730 bbl., while the wells in the Isthmus of Tehuantepec came in with an average of 770 bbl. Development is summarized in Table 1. In the Southern fields 63 wells were drilled in 1929, of which 23 were producers, the best being drilled in Paso Real. This development tends to show that the southern extension of Dos Bocas-Alamo fault from Alamo to San Isidro terminates at San Isidro. The two wildcat wells completed in 1929, one in Magiscatzin and the other in Xicotencatl, were failures, and at the end of the year there were eight wildcat wells drilling and material was being hauled for two more.

Jan 1, 1930

By E. B. Hunt

Paraffin deposition has been studied in the laboratory under conditions simulating deposition in well tubing. A theoretical analysis has been made of the cooling of the oil and the precipitation of paraffin from the oil as it flows up the well tubing and through surface flowlines. It is proposed that paraffin deposits are initiated by the precipitation of paraffin directly on or adjacent to the pipe wall and grow by diffusion of paraffin from solution to the deposit. This mechanism is consistent with laboratory and field observations, and has proved useful in the design and interpretation of laboratory paraffin-deposition tests. Tests have been made of the effect of plastic pipe coatings and chemical additives on paraffin deposition. INTRODUCTION Paraffin deposits which form in well tubing and surface flowlines interfere with production and must be removed. Over the years much progress has been made in developing and improving methods of removing these deposits after they form. Much less progress has been made in developing methods of preventing or inhibiting the formation of paraffin deposits. This is due, it is believed, to the lack of knowledge of the mechanism of paraffin deposition, the absence of satisfactory laboratory testing methods and the difficulties in evaluating the results of field tests of preventive treatments. The present investigation was undertaken to elucidate the mechanism of paraffin deposition and to develop suitable laboratory tests for studying the inhibition of paraffin deposition in well tubing and surface flowlines. Current theories on the mechanism of paraffin deposition have been evolved from field observations, from laboratory studies of various factors which might be involved in paraffin deposition, and from laboratory paraffin-deposition tests.1-9 Paraffin deposits have been formed in the laboratory by immersing a cold finger into a hot wax-oil solution and by flowing hot wax-oil solutions through cooled pipe or over cooled plates. These laboratory conditions differ in important features from field conditions, and the observed deposition behavior is not entirely field-like." Thus, there is reason to question the field applicability of the results of these tests. The present investigation was undertaken to determine how to perform and interpret laboratory paraffin-deposition tests to obtain information on the inhibition of deposition in the field. The paraffin problem in the broadest sense encompasses the formation of any predominantly organic deposit in well tubing, surface flowlines and other equipment in contact with crude oil or gas. The present investigation was limited to paraffin deposition involving the precipitation of paraffin wax from solution by cooling and its concentration in a deposit on a cooled surface. This probably excludes its applicability to those problems arising from asphaltic-base crudes, but not those arising from paraffin-or mixed-base crudes. This also excludes its applicability to emulsion and congealing oil problems which are often included as part of the paraffin problem. The phenomenon of cooling appears to be the controlling factor in paraffin deposition involving the precipitation of paraffin wax and its concentration in the deposit. Deposits of this type are usually found in the field only where cooling occurs. Early in this laboratory investigation, it was not found possible to form deposits under constant temperature conditions from a wax-oil slurry, either by steady flow through pipe or by gas-lift up a pipe. Thus, the investigation was limited to situations involving cooling. THEORY The relationships involved in establishing the temperature profiles in an oil stream as it flows up well tubing with a linear (geothermal) pipe-wall temperature distribution or through surface flowlines with essentially constant pipe-wall temperature are presented in the Appendix. The relationship between radial distance in the pipe and the rate of cooling of the oil is then combined with a relationship between cloud point and rate of cooling to develop the pattern of formation of a wax cloud in the oil. The following discussion of paraffin deposition under various laboratory and field conditions is based upon this development which is presented in the Appendix. PARAFFIN DEPOSITION IN SURFACE FLOWLINES The average temperature of the oil coming out of a well is somewhat higher than the ground temperature. Thus, the oil continues to cool on its trip through the surface flowline, and wax deposition can occur. The temperature distributions calculated from Eq. A-4 are given in Fig. 1. As can be seen, almost all the cooling occurs in the first 500 ft from the wellhead. In addition, the radial temperature gradient near the wall decreases rapidly with distance and becomes very small after a few hundred feet. Thus, growth of a paraffin deposit would be expected to decrease rapidly with distance from the wellhead and become negligible after a few hundred feet, since growth is dependent on concentration gradient. Wax precipitation and diffusion of wax to the already

By George A. Macready

Trinidad, British West Indies, is an island near the north coast of South America, situated between latitudes 10" and 11" N., and opposite the numerous outlets of the Orinoco River Delta. It is separated from Venezuela by the Gulf of Paria (salt water) and straits over 5 mi. (8 km.) wide. The area of the island is approximately 1750 sq. mi. (453,-250 hectares) and the population is approximately 400,000. The climate is tropical with an annual rainfall of from 45 to 60 in. (114 to 152 cm.). The oil fields consist of several units, or fields, located in the southern half of the island. Approximately 90 per cent. of the total production has been yielded by fields situated within 7 mi. (11.3 km.) of the famous asphalt lake and on the southwest peninsula. The most important producing fields, or units, are the following, which are shown on the accompanying map: Brighton, or Pitch Lake Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated beside the famous Pitch Lake; it even encroaches on the lake. Vessigny Field, operated by the Trinidad Lake Petroleum Co., Ltd., is situated 2 mi. (3.2 km.) south of Pitch Lake. Lot One Field, operated by the Petroleum Development Co., Ltd., the United British Oilfields of Trinidad, Ltd., and Stollmeyer, Ltd., is situated 3 mi. south of Pitch Lake upon Lot One of Morne 1&apos;Enfer Forest Reserve and adjoining properties. Parry Lands Field, operated by the United British Oilfields of Trinidad, Ltd., and the Petroleum Development Co., Ltd., is situated 31/2 mi. south of Pitch Lake on Lot Three of Morne 1&apos;Enfer Forest Reserve and adjoining properties. Point Fortin Field, operated by the United British Oilfields of Trinidad, Ltd., is situated at Point Fortin, 6 mi. southwest of Pitch Lake. Fyzabad Field, operated by Trinidad Leaseholds, Ltd., is situated several miles southwest of Fyzabad Village and 6 mi. south-southeast of Pitch Lake. Barracpore Field, operated by Trinidad Leaseholds, Ltd., is situated several miles south of San Fernando and 15 mi. (24.14 km.) east of Pitch Lake.

Jan 1, 1921

By W. A. Koehler, M. E. Hinkle

INTRODUCTION THE oxidation of pyrites and marcasite in coal-mine strata to produce discolored acid mine drainage has long been explained by chemical reactions occurring in three stages: I. The iron sulphide minerals are oxidized by air in the presence of water to produce a nearly colorless solution of fer¬rous (iron) sulphate and some sulphuric acid. 2. The ferrous sulphate and part of the sulphuric acid combine with additional oxygen to form ferric (iron) sulphate. 3. The ferric sulphate hydrolyzes to form a reddish-brown precipitate and additional sulphuric acid. Nevertheless, chemical data alone are not sufficient to explain all observed facts. The first stage seems to proceed more slowly in the chemical laboratory than in nature. The second and third stages nor¬mally occur to a marked extent within a few days with raw mine water. However, the visible discoloration that characterizes these latter stages will not develop for months if the mine water is sterilized. By means of bacteriological techniques, two organisms have been isolated from acid coal-mine drainage. These are believed to have a part in promoting the chemical reactions summarized above. One organism is considered to be Thio¬bacillus thiooxidans, which is known to be able to convert elementary sulphur or sodium thiosulphate to sulphuric acid. Its relation to the formation of acid mine drainage has not yet been established. Apparently it does not promote the oxida¬tion of ferrous iron compounds in mine, drainage to the ferric state. The second organism has not been identi¬fied by name but is described as "Gram negative, non-spore-forming rods approxi¬mately 0.4 micron wide by o.8 to 1.0 micron long." A pure culture of this when added to sterile mine water will cause the latter to become amber and develop the typical rusty precipitate. However, it has not been found to convert sulphur com¬pounds to sulphuric acid. Further research is planned to determine whether or not these microorganisms play a significant part in the first stage of oxidation whereby pyrites and marcasite minerals go into solution. Some of the conditions found in abandoned sections of coal mines, such as a reduced percentage of oxygen and increased percentage of carbon dioxide in the air, as well as the existing temperature and acidity ranges, will be tolerated by and may even be favorable to these organisms. ACID COAL MINE DRAINAGE Acid coal mine drainage has been the concern of coal mine operators, industrial¬ists, sportsmen and public officials for many years. The amount of acid flowing into our streams in the coal-producing areas varies considerably from mine to mine and from

Jan 1, 1948

1-Iron and Steel JOHN A MATHEWS, Chairman Ralph H SWEETSER Vice-chairman WILLIAM CAMPBELL, Vice-chairman MAX ROESLER, Secretary Iron Ore CHARLES B MURRAY, Chairman R C ALLEN W O HOTCHKISS MAX ROESLER ERNEST F BURCHARD THOMAS T READ DWIGHT E WOODBRIDGE M M DUNCAN WILLIAM KELLY CARL ZAPFFE C T FAIRBAIRN CHARLES F RAND

Jan 1, 1923

By B. N. Bose, M. F. Hawk

SINCE Davenport and Bain&apos; introduced the isothermal transformation technique for the study of austenite decomposition in steels, a new field of investigation has opened up. Extensive research has been carried out on many different steels, but relatively little work has been done on eutectoid transformations in analogous alloy systems. The researches of Smith and Lindlief,² Mack,³ and Klier and Grymko²0 on the beta-phase transformation in copper-aluminum alloys, of Hibbard, Eichelrnan, and Saunders4 and Smith5 on the kappa-phase transformation in copper-silicon alloys, of Chaudron and Forester6 on the decomposition of "FeO," and of Wasserman7 on similarities between the iron-carbon, copper-aluminum, copper-tin, and copper-beryllium systems essentially comprise the field. The iron-nitrogen system, in view of its remarkable similarity to the iron-carbon system, is particularly attractive for the study of eutectoid decomposition. The present investigation is concerned with the study of isothermal transformation, proceeding by the familiar nucleation and growth processes, and of martensitic transformation characteristics of pure iron-nitrogen alloys. The kinetics of transformation and the morphology of the transformation products have been investigated, for these must be the factors determining the properties and behavior of the final product. The Iron-Nitrogen System he binary iron-nitrogen phase diagram has been a matter of considerable disagreement among vari01.1s investigators. However, the phase diagram according to Eisenhut and Kaupp8 and Lehrer10 is now considered essentially correct as reproduced in fig. 1. The important values, 2.35 pct nitrogen and 591°C, for the co-ordinates of the eutectoid point (obtained from this diagram and used in the re- search to be described) were confirmed in a concurrent study of Paranjpe, Cohen, Bever and Floe." The eutectoid decomposition involves the transformation of the ? face-centered cubic interstitial solid solution of nitrogen in iron to the a body-centered cubic interstitial solid solution of nitrogen in iron and the ?&apos; nitride of iron. This nitride is essentially the compound Fe,N; it also possesses a face-centered cubic lattice but a considerably larger one than the ?; the nitrogen atoms in ?&apos; are arranged in an ordered way in the centers of the unit cubes.8,10,11 A martensitic structure has also been reported8,12 in iron-nitrogen alloys and was studied in the research to be described here. Materials and Methods The specimens used in this investigation were prepared by nitriding "pure" iron. This iron was supplied by the Westinghouse Research Laboratories and is the product bearing their trade name "Puron"; it contains about 0.04 wt pct total impurities, the major portion of which is oxygen. Specimens were ribbons several inches long, a tenth of an inch wide, and 0.125 mm thick; this was the

Jan 1, 1951

By Henry B. Smith, S. Paul Lindau

ThREe years ago it was decided by the management to granulate the matte that is produced in the smelter of the St. Joseph Lead Co. at Hereulaneum, Mo., thereby doing away with a large amount of labor in handling the matte and in subsequent crushing. On Mar. 1, 1915, the granulator was put in operation and up to Jan. 1, 1916, 18,735 tons had been granulated. The four blast furnaces have a daily output of about 280 tons of pig lead and 100 tons of matte assaying about 11.0 per cent. Pb. It is expected that projected improvements in roasting methods will eliminate more sulphur from the charge, and cut down the matte-fall to about one-half of the present figure. The blast furnaces are tapped into movable forehearths or settlers, 6 ft. by 4 ft. by 22 in., the slag overflowing into 27-cu. ft. slag cars which are hauled to the dump by electric locomotives. Previous to the adoption of granulation, the matte was tapped from the forehearths into small slag pots which were dumped after cooling. The matte cakes were broken with sledges, and transported to the crushing plant for fine crushing and screening. Here the matte was reduced to 1/4-in. size before being fed to the roaster bins. A Wedge and a Holthoff mechanical furnace are used for preroasting before sintering on the Dwight and Lloyd machines. The matte is returned to the furnaces as an iron flux until the gradually accumulating copper content reaches about 7 per cent., after which it is put aside to be concentrated in a small copper blast furnace, the resultant high-grade matte being sold. When the matte does not settle readily from the slag, two settling devices are often used, the second one being a large catch-pot, which gathers any matte that may overflow from the forehearth, the slag then overflowing from the catch-pot into the slag cars. When full of matte, the catch-pot is removed, allowed to cool, and the contents broken and crushed. a With the present plan of granulating, the matte is tapped into 6-cu. ft. iron ladles. These are transported to the granulating plant by a 5-ton

Jan 1, 1917

By W. Spencer Reid

ALTHOUGH there have been some developments during the last five years which have had far- reaching and important bearing on lead smelting, it cannot be said that any basic principles of pyrometal-lurgy have been discovered. Eighteen or twenty years ago the Dwight & Lloyd sintering machine was intro-duced and literally turned the roasting end of lead smelting upside down. There has been nothing com-parable to the advent of the sintering machine during recent years. Actual blast-furnace practice today is slightly, if any, better than it was five years ago ; although immeas-urably better than it was twenty to thirty years ago. Some tell us that as far as cleanness of slags is con-cerned, it is no better today than in the days of the old Romans. The metallurgist of a generation ago did very good work, considering the equipment he had available. It is true he was working with the cream of the ores, the clean oxides and carbonates and the low-zinc sul-fides. He was troubled very little with high zinc and selected his type of slag according to preference of -some authority such as Eilers, Iles, Raht, Hahn, etc. As these free-smelting ores were depleted the complex ores were encountered, and the metallurgist gradually discovered that he had to forget the old type slags and run a slag according to the percentage of zinc on the charge. I believe it is now universally agreed that SiO2 and CaO must be lowered and FeO raised in a slag as the ZnO increases. The ratio of these variations is practically uniform and can be relied upon over wide fluctuations of the determining element, zinc. These "bastard" slags, as they are sometimes inappropriately designated, are actually in daily use, and the metallurgist of today has been forced to adopt certain standards, as a guide to successful operation. These slags practically refute the old Eilers&apos; theory that all good slags are chemical combinations of SiO2 with FeO and MnO, and CaO and MgO. Eilers&apos; and the other type-slag theories were based upon the assumption that a good slag must con-form to a definite formula, such as 3 (FeO)2 SiO2 + 2 (CaO)2 SiO2 or 2 (FeO)2 SiO2 + 2 (CaO)2 SiO2 which respectively figure 31.3 and 36 per cent SiO2. The SiO2 was supposed to remain constant even with the entrance of impurities such as Zn and A1,0? into the slag. The increasing amount of impurities, espe-cially Zn, soon discredited the theory, for in actual practice the slag failed to run freely.

Jan 1, 1927

By E. A. Gulbransen, J. W. Hickman

THE physical and chemical structure of the oxide films formed on metals and alloys is of interest in our understanding of their protective properties. According to Pilling and Bedworth,1 if the specific volume of the oxide is equal to or greater than that of the metal, a compact or continuous structure results; if the volume of the oxide is less, a cellular or porous structure forms. With the cellular type of coating the surface layer of oxide offers no impedance to oxidation; at a given temperature the rate of oxidation is quite constant. On the other hand, the compact type of coating acts as an effective barrier to oxygen and the rate of oxidation will follow a parabolic law. The recent work of Gulbransen2 and of Leontis and Rhines3 on the oxidation of magnesium indicates that it is not necessary for the volume of the oxide to be greater than that of the metal in order that the oxidation may follow a parabolic rate law. One exception to the rule of Pilling and Bedworth&apos; is noted by Scheil;4 namely, tungsten. At 500° and 700°C long-time oxidations indicate a linear rate law with time. However, Dunn&apos;s5 oxidation measurements from 700° to 1000°C indicate that a parabolic rate law is followed. The oxide is mainly yellow W03 with a thin layer of the blue oxide. Preliminary results on the oxidation of tungsten6 in the temperature range 400° to 500°C indicate that the oxidation does proceed according to a parabolic rate law. Irrespective of the actual rate law that tungsten may obey, it is of interest to compare the results obtained on the oxidation of tungsten in the thin film region with those found when the metal is scaling. A time-temperature study of the oxides formed on both molybdenum and tungsten may indicate whether there exist any peculiarities in the oxide structures of the thin film region compared with those of the scaling region of oxidation. In a recent paper the authors&apos; presented an investigation of the structures of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper. The results of these studies are presented in graphical form as existence diagrams of the oxides on a time-temperature scale. The existence diagrams of the oxides occurring on some of the metals are simple and show few chemical transitions, but there are many cases in which the physical state of the oxide surface changes as a function of time and temperature, as evidenced by the appearance or disappearance of orientation effects and sharpness of patterns. In general an increase in temperature results in an increase in

Jan 1, 1947

By L. A. Willey

IN 1953, a method for filtering a liquid phase from solid phases while in equilibrium at elevated temperatures was devised at the Alcoa Aluminum Research Laboratories. Since then, it has been applied to the investigation of liquid-solid equilibrium in metallic systems. In application, the method simplifies the centrifuge filt.ration procedure as developed by Scheil and described by Gebhardt Fig. 1 shows a sketch of the filtering apparatus located within a thermal analysis furnace. It consists of a stainless steel filter crucible A, into the bottom of which a porous carbon filter disk B, 1 3/4 in. diam by 1/4 in. thick, is sealed to the shoulder and rim with carbonaceous cement. The base of the filter crucible, machined to an angle, fits into a tapered seat at the mouth of a stainless steel vacuum chamber C. A connecting tube from the vacuum chamber to a vacuum line also serves as a means for supporting the apparatus from the base of the furnace. An alundum crucible D of 25 ml capacity is placed with- in the vacuum chamber below the filter for collecting the filtrate. Two thermocouples E, in stainless steel protection tubes, which extend from 1/16 to in. above the center of the filter, are mounted on the rim of the filter crucible. One thermocouple is used in differential connection with the furnace control thermocouple to regulate rates of heating and cooling. The other serves as a means for recording the temperature of the alloy prior to filtering. A suitable mold coating is used on exposed surfaces of stainless steel parts to guard against attack upon these parts as well as to avoid contamination of the alloy samples. A mold wash prepared from precipitated CaCO, is suitable for aluminum alloys. The porous carbon for the filter disks and the carbonaceous cement, grade 200 (graphite base), were obtained from the National Carbon Co. Porous car-bon, grade Nos. 10 to 60, has been employed. Grade No. 40, however, appeared to give the optimum advantages in operation. In operation, an alloy sample is remelted and heated to about 50°C above its liquidus temperature. At the same time, the filter apparatus is preheated to about the same temperature. The alloy then is cast into the filter crucible.

Jan 1, 1957