Search Documents

By AIME AIME

S ULFURIC acid made in the United States during the last four years has averaged approximately 7,000,000 tons of 50" B6 acid a year. This is double the production of the year 1913. About 66 per cent of the acid is made from sulfur, 16 per cent from pyrite, 13 per cent at copper, lead, and zinc smelters, and the remainder from miscellaneous sources it her the chamber process or the contact process, (at some plants both) is used. In 1923, the contact process accounted for nearly 30 per cent of all the sulfuric acid made in this country and since then it has been increasingly employed. It was first introduced here in 1898, and has always .proved less expensive than the chamber process for the manufacture of .acid of high concentration and purity, but the latter produces acid of low strength suitable for many industries.

Jan 1, 1929

By C. E. Birchenall, G. Derge

IN studying the kinetics of slag-metal reactions, it has become increasingly apparent that a complete knowledge of all aspects of interface phenomena will be required to clarify these processes adequately. A part of the data required for all oxidizing slags used in the refining of impure iron to steel is the rate of exchange of iron between the slag and metal phases. The simplest equilibrium of this type is that between liquid iron and iron silicate slag when both phases are equilibrated with the silica crucible containing them. In this study, the exchange of iron between the two liquid phases has been measured by using radioactive Fe as tracer. The observed high exchange rate indicates the ease with which such interfaces may be crossed in refining processes. The experiments required for this study involved relatively minor and normal modifications of well established techniques. Melting was accomplished by induction heating in heavy walled, fused silica, rotating crucibles." Rotation was used to minimize dilution of the slag by crucible erosion. The melting stock was ingot iron. Slags were prefused in iron crucibles using chemically pure grade oxide reagents. The special conditions applying to the active iron additions will be described for individual experiments. Suitable precautions were observed with regard to protection against radiation hazards.' Identification of Activity This particular study was initiated several years ago, but held in abeyance because the radioactive iron available at that time contained a foreign activity which concentrated in the slag so as to mask the iron activity and render the results unin-terpretable. With the benefit of experiences from other studies, radioiron of suitable purity can now be prepared. As received from the Isotope Div. of A.E.C., the unit appears to contain Fe + Fe50 and a high activity cobalt. The cobalt and iron are separated by repeated ether extractions, and the purified iron stored for sufficient time for the Fe'7 44 day half-life) to decay to negligible activity, leaving only Fe as the active isotope. This was confirmed by the absorption curves for slag and metal samples from heat No. 1. In Fig. 1 the experimentally measured points for the absorption curves of slag and metal are fitted by the calculated slope of 5.8 mg per sq cm in aluminum, which corresponds to the Mn K doublet emission resulting from the capture of an orbital electron of Fe" by the nucleus. This shows that the radioactive species are the same in both slag and metal and identifies it as Fe55 Description of Individual Heats For the first heat, the radioactive iron was contained in the prefused slag. The active Fe55 had been precipitated with carrier and was added as Fe2O3 during fusion in the iron crucible. The charge of 500 grams of ingot iron was melted, the protective iron sleeve added, rotation started, and a prefused, inactive slag was added to allow the system to approach equilibrium. After about 5 min at temperature, the wash slag was skimmed and the active slag added. Initial slag and metal samples were taken as soon as the slag was molten. Additional samples were taken at indicated intervals thereafter. Slag samples were dipped with a small iron spoon and metal samples were sucked into 1/4 in. ID silica tubes. The slag and metal samples were pulverized and mounted for radioactive counting. The slag samples were analyzed chemically for FeO. Temperature was read after the last slag sample by immersion of a Pt-Pt-Rh thermocouple protected by a fused silica sheath. Since no significant variation of rate with temperature was observed

Jan 1, 1954

By J. H. Scaff, J. E. Kunzler

The measurement of the electrical, thermal, and magnetic properties of metals at low temperatures, primarily in the range of liquid helium below 4.2°K, is a powerful tool for investigating many of the fundamental properties of the metallic state. Such measurements also have many practical applications, particularly as an analytical tool. One example of the practical utility of such measurements is illustrated by a short study we have made of the low-temperature resistance of copper used in preparing varistors. Copper-oxide varistors are prepared by the thermal oxidation of copper. This results in the

Jan 1, 1959

By R. D. Schoone, J. T. Michalak

Recovery, recrystallization, and texture development of a cold-rolled aluminum-killed steel have been studied during simulated box annealing. Two different initial conditions existed prior to cold rolling: 1) essentially all of the nitrogen in solid solution and 2) most of the nitrogen precipitated as AlN. The combined effect of nitrogen and aluminum in solid solution before annealing was to inhibit recovery and sub-grain growth at temperatures above about 1000°F and to raise the recrystallization temperature range on continuous heating at 40°F per hr from 1000"-1050°F to 1065"-1085°F. For the material with nitrogen and aluminum initially in solution there was an inhibition in the nucleation of the (001) [110] texture component and an enhancement of the (111) [110] texture component. The differences in annealing behavior mzd texture development are attributed to preprecipitation clustering of aluminum and nitrogen at subboundary sites developed by prior cold working. THE annealing of cold-worked aluminum-killed steels has been the subject of numerous investigations.'-'2 These studies have been concerned with kinetics of recrystallization, with microstructure and texture development, and with the individual and combined effects of composition, thermal history prior to cold rolling, and heating rates during subsequent annealing. It has been shown that the inhibition of recrystallization, and the development of the pancake-shaped grain and recrystallization texture characteristic of aluminum-killed steels, can be associated with the precipitation of A1N particles during a recrystallization anneal involving heating rates in the range 20" to 80°F per hr. If the AIN is precipitated before cold rolling or if more rapid heating rates are employed, the cold-rolled steels recrystallize more rapidly to an equiaxed grain structure and texture comparable to that of rimmed low-carbon steel. The retardation of recrystallization, the development of the elongated grain structure, and the pronounced (111) texture have been attributed to: 1) precipitation of A1N at prior cold-worked grain boundaries to form a mechanical barrier to grain boundary migration;' 2) precipitation on the boundaries of the growing recrystal-lizing grains as well as on cold-worked grain boundaries;'" and 3) preprecipitation clustering or precipitation on subboundaries to retard recovery, nucleation, and growth. The present study was undertaken to study in more detail recrystallization and texture development during commercial box annealing of cold-rolled aluminum-killed steels. Comparison of the annealing be- havior after cold rolling, for two different conditions prior to cold rolling, was made in an attempt to define more clearly the role of aluminum and nitrogen in forming the recrystallization texture. A) MATERIAL AND PROCEDURE The material used in this investigation was a commercial low-carbon aluminum-killed steel which was hot-rolled with a finishing temperature of about 1565"F, then coiled at about 1020°F. The composition, in wt pct, was: 0.050 C, 0.30 Mn, 0.007 P, 0.019 Si, 0.03 Cu, 0.02 Ni, 0.02 Cr, 0.045 Al, and 0.004 N. Two 4.5 by 13 by 0.078 in. sections were cut from the center section of a hot-rolled panel and one of these was reheated to provide two different conditions prior to cold rolling: low AlN: as commercially hot-rolled, with aluminum and nitrogen in solid solution; and high AlN: as commercially hot-rolled, then reheated at 1300°F for 3.5 hr to precipitate most of the nitrogen as AlN. ~etallc&a~hic examination indicated that the reheating did not change grain size nor carbide distribution (some spheroidization of pearlite was noted). Texture analysis at half-thickness level showed that both sections had the same substantially random as-hot-rolled texture. The results of check chemical analysis of each sample are given in Table I. Both sections were cold-reduced 65 pct on a laboratory rolling mill to a final thickness of 0.027 in. Cold rolling, in one direction only, was in the direction of the prior hot rolling. Specimens 1.0 by 1.25 in. were cut from the cold-rolled sheets and given a simulated box anneal in an atmosphere of 2 pct HZ-98 pct He. Specimens were heated at a constant rate of 40°F per hr from room temperature to various temperatures in the range 750" to 1300°F and cooled immediately by withdrawal to the water-cooled end of a tube furnace. The temperature in the 6-in. uniform hot zone of the furnace was controlled within 3"F. Selection of the individual specimens was made to give a random distribution of annealing temperatures with respect to location in the cold-rolled sheet. At least two specimens of each condition were annealed to the same temperature and smaller specimens for light microscopy, transmission electron microscopy, and X-ray studies were prepared from each of these. Rolling-plane sections for each of these studies were taken at half thickness. Light microscopy and transmission electron micro-

Jan 1, 1969

By Marc Lemieux

Computer pit design techniques generally make use of models in which the deposit is represented by a regular array of data. Using a regular system, the number of data points required to represent the air, waste and mineralization in a large deposit become excessive. The number of blocks used to describe the deposit is dependent upon the block size. The quality of the pit wall slope design also is dependent upon the block size used and the method of defining the slope. The error associated with reserve calculations becomes greater with increasing block size. A deposit model consisting of variable sized air and mineralized blocks has been developed at the University of British Columbia and improved upon at Climax for pit design work. The method permits put- ting the entire model in core for rapid data processing. This permits the use of a versatile cone generation technique which allows close adherence to variable slope constraints in all directions. The conical shape is approximated by rectangles on each level which equal the area of the ideal conical intersection. The shape of the intersection may vary from approximately circular to elipsoidal. The approximate cone shape is controlled by the slope constraints applicable at the point of intersection on the bench. The overall modeling technique greatly assists the pit design engineer in developing a high quality pit design.

Jan 1, 1977

By Walter S. Weeks, Vitaly S. Grishkevich

Considerable difference of opinion seems to exist as to whether the rate of air flow when a fan is placed on a given duct should be determined by the use of static pressure or total pressure characteristics. A little study will show that both methods are correct. Assume that a fan is connected to a duct by an expansion piece as shown in Fig. 1, and that steady flow is established. Considering the atmospheric pressure as zero pressure, let the static head at the outlet of the fan be h and the velocity at this point be vl. The total head at the outlet is then h + „"• The total head at this point must be equal to the total head at the end of the duct plus the losses that have occurred between the two points. Left be the friction loss in the straight duct, s the shock loss in the dif- fuser, and v2 the velocity at the end of the duct. Then ig. 1.—Fan on duct. A curve showing the value of the left-hand side of the equation for different rates of flow is the total pressure characteristic of the fan, while a curve showing the value of the right-hand side is the total pressure characteristic of the duct. If these two curves are plotted on the same chart, the intersection indicates the rate of flow when steady flow is established. We may look at this problem in another way. The static pressure at the outlet of the fan is the static pressure of the fan and it is also the static resistance of the duct from that point to the end. The friction in the straight duct is f. If the duct were the same area as the fan outlet, would be the static resistance of the whole duct system. In the present case, however, this resistance is decreased by the change of velocity head into static head in the expansion piece. If conversion were perfect, the static pressure recovered would be

Jan 1, 1931

By G. Sherburne Rogers

One of the features of oil-field work that puzzles operator, chemist, and geologist alike, is variation in the gravity of the petroleum produced on neighboring leases or even from adjoining wells. Few fields in the United States yield oil that is of uniform gravity throughout; in some fields the different grades are produced from different sands, in a few from different formations, and in many from different areas in the same sand. In a few cases, perhaps, a common assumption—that the heavier oil is derived from the lighter through the escape of the more volatile constituents—is valid, but many cases can not be explained in this way. Although in the California fields the specific gravity of the oil generally decreases with depth, there are numerous exceptions to this rule; and, as in many other regions the light oil is found nearest the surface, it is evident that evaporation underground is generally an unimportant factor. It is generally recognized that the great differences between petroleum from widely separated fields are due largely to differences in age and degree of metamorphism and to variation in the composition of the original organic matter; but in the writer's opinion some of these broader differences, as well as most of the minor variations in the character of the oil from any one field, are due to the local action of natural reagents such as sulphur or oxygen. This is particularly likely to be true if the oil has migrated from one formation to another, as in the California fields; and in some arcas it appears that variation in sulphur content may even afford a rough index of the extent or distance of the migration. It is the purpose of this paper to call attention to the chemical action of sulphur and oxygen on petroleum, to show that the gravity of the oil from any one field is intimately related to its sulphur content, and to discuss the possi-

Jan 1, 1918

By Clarence E. Sims

An effort has been made to give both a comprehensive and simplified picture of the origin, modes of formation, and characteristics of nonmetallic inclusions in steel. Exogenous inclusions, those formed by mechanical entrainment or heterogeneous reaction, have their principal source in ladle refractories. Mechanical emulsion is not considered a likely mechanism. Endogenous inclusions, resulting from homogeneous reactions, are formed mainly during cooling and freezing. They are principally oxides and sulfides but include some nitrides and carbides. Deoxidation affects both the quantity and character of such oxide inclusions and significantly affects the size and shape of sulfides. The importance of inclusions is largely in their effect on mechanical properties. It is fitting and proper that we should honor the memory of those technical giants who have left such a rich heritage to our profession. Today, according to annual custom, we pay tribute to such a man. To have been chosen to play a part in this observance prompts in me an inordinate pride while I am humble before the responsibilities of my task. The ranks are growing thin of those who had the good fortune to come under the personal influence of Professor Howe, but the number who continue to benefit from his legacy of technical wisdom con-stantly increases. I am among the latter. One has only to read his works to appreciate his unusual ability to take data and observations from many sources and give them a clear and comprehensive

Jan 1, 1960

By Charles Fettke

IN THE present day manufacture of glass nearly pure quartz sands are used almost exclusively as the source of the silica, which is the major constituent of all common varieties of glass. Ordinary soda-lime, such as bottle, common tableware, plate, and window glasses, contain from 65 to 75 per cent. of silica. OCCURRENCE Glass sands occur in nature either in the form of loose, unconsolidated sediments or in deposits in which the individual grains have been more or less thoroughly bound together by some cementing agent so as to form sandstones. While deposits of sand and sandstones occur both widely and abundantly distributed, deposits that are sufficiently free from other constituents than quartz grains, so that they can be employed in the manufacture of the better grades of glass, are, comparatively speaking, of rare occurrence. The major portion of the glass sand produced in the United States comes from sandstones. In order to be suitable for glass sand, they should be rather friable. The rock should break down readily along the cementing material between the grains and should not break across the grains rather than along the bond. Some of the sandstones used are so friable that only light shots of slow-burning dynamite are necessary to disintegrate them sufficiently for hydraulic mining, while others have to be passed through crushers in order to disintegrate the rock into its individual grains.

Jan 2, 1926

By Edward L. Clark, Garrett A. Muilenburg

THE first record of the discovery of iron ore in Missouri was Marquette's observation in 1673 of brown iron ore, or limonite, in the Mississippi River bluffs just north of the mouth of Apple Creek in southeastern Perry County. There is no record of any attempt to mine or smelt Missouri iron ores until 1815, when the Ashebran furnace was erected at the Stouts Creek shut-in near Arcadia, Iron County. Some limonite was treated in this furnace, the first iron furnace west of Ohio, but most of the ore was hematite from Shepherd Mountain and adjacent deposits. Eight years later, in 1823, the Perry furnace five miles north of Caledonia, Washington County, was constructed to smelt limonite ore. It was not until 1890 to 1900, however, that these ores attracted considerable attention. Nearly 300,000 tons had been produced by 1911, and this production had come from 24 counties in the Ozark region. For the next two decades, until 1931, essentially all activities ceased. During the depression years of the thirties when employment was low many people turned to the brown ores for subsistence; consequently production was increased. World War II produced another stimulus to the industry. The availability of risk capital in the past three years has revived interest in these deposits, although no appreciable increase in production has resulted.

Jan 1, 1954

By Charles T. Holland

IN connection with the problems of bumps in coal mines, much has been written concerning the manner in which roof action and methods of mining enter [ ] into the pressure effects observed but little has been written upon the relationship between the physical properties of coal and associated rocks and the cause of bumps. The question of the strength of bituminous coal, of its elasticity, and the energy it can absorb and store has been neglected to a considerable extent in connection with this problem. STRENGTH OF COAL It is generally agreed that one of the necessary conditions for bumps is a strong [ ] coal.1 Therefore, since the strength of coal is an important factor, a study of this property should be made. Several investigators have conducted laboratory experiments upon the strength of coal, using small cubical or rectangular test pieces. An attempt will not be made to go into all of these investigations, but they are briefly summarized in Table I. Experiments of the U. S. Bureau of Mines8 and of Lawall and Holland (pp. 27 and 34 of ref. 9), however, indicate that regardless of whether the coal is a soft and weak semibituminous (Pocahontas No. 3) or a hard and strong bituminous (Stockton) coal, the maximum ultimate unit stress developed in laboratory tests is higher in small cubes than in larger cubes of the same coal.

Jan 1, 1942

By Charles Becker

THE practice of drying phosphate in Florida is as old as the industry, which began a little more than half a century ago. The methods, however, have changed considerably. At first, the natural process of exposure to the sun and air was used, later supplemented by wood fires beneath open-air stationary dry kilns and drying towers of various designs. It was not until the early nineties that rotary driers came into use, and at first they were of very small design and fired with wood. As the industry grew and tonnage increased, so likewise grew the number and size of rotary driers, until today the largest installations are 6 ft. up to 7 ft. 6 in. in diameter, and 55 to 60 ft. long, fired with crude oil. The reasons for drying phosphate rock are: (1) to eliminate freight on water in the shipment and (2) to facilitate the good grinding qualities required by the buyers in their acidulation. Phosphate pebbles vary materially in natural characteristics and each property has a direct bearing on the processing. In making comparisons of cost and operating conditions, the following are usually taken into consideration: 1. The hard dense pebbles, which contain very little interior moisture and 6 to 8 per cent total moisture, usually produced from the low-grade deposits. 2. The lighter, porous pebbles, which contain 4 to 5 per cent interior moisture and a total moisture ranging from 9 to 15 per cent. 3. The product of recovery operations using oily reagents, containing from 15 to 25 per cent moisture. 4. The size of the pebbles. Usually the plus 5-mesh material is considered as "coarse rock"; the minus 5-mesh plus 24-mesh is "fine rock," and the minute particles below 24 mesh are called "concentrate." 5. The amount of moisture allowed in the dried product. The practice is generally to dry down to 1.5 to 2 per cent moisture. There is, however, an actual range in guarantee of from 1 per cent maximum to 3 per cent maximum.

Jan 1, 1936

By F. W. Smith

Within the Northern Pennine Orefield, England, intersections of fluorite veins are generally richest in ore, and their recognition enables investigation of the ore potential of the intersecting bodies. A method, based on routine analysis of fluorite for yttrium, has been used with success in mines of the district to predict the location of intersections in partially developed fluorite-bearing ore bodies. This short note is intended as a brief introduction; the details of United Kingdom applications are to be published at a later date. Geology The Northern Pennine Orefield is the second largest fluorspar-producing region in Britain. The associated minerals galena, sphalerite, chalcopyrite, barite, and witherite have all been extensively worked in the past but, with the exception of a single barytes mine, all of these operations are now abandoned. Galena alone is recovered as a byproduct of fluorspar beneficiation. At the present time two companies are producing about 38,000 tpy of fluorspar from high grade vein ore bodies, and a number of concerns are actively prospecting in old lead workings. The mineralization is localized in veins and replacement flats within favorable lithologies in an alternating limestone, sandstone, shale sequence. Since the thickness of individual beds is not great (generally less than 20 m), vein bodies tend to be ribbon-shaped, with length greatly exceeding width and height (Dunham). They thus present difficult exploration targets for conventional diamond drilling techniques. Ore grade varies greatly along the veins, which can change rapidly in character from mineral stained fault gouge to massive mineral bodies up to 10 m in width. It has been known for a very long time that the richer ore bodies tend to be associated with vein intersections in favorable beds. It is assumed that vein fissure intersections provided vertical channelways through which hot ore-bearing brines were able to ascend from deeper cavities in the sequence. Thus investigation of intersections at other horizons generally yields further ore bodies. Technique The relative concentration of yttrium in fluorite is a good indicator, in the North Pennines, of the direction of flow of mineralizing fluids. In all of the ore bodies so far studied in detail in this region, the concentration of yttrium increases markedly in the direction of vein intersections that are believed to have acted as feeder zones to the remainder of the bodies. The reason for this relationship is probably connected with the degradation of soluble rare earths-fluoride complexes by the changes in various physicochemical parameters of the hydrothermal fluids as they entered the ore body cavities from the feeder zones. The simultaneous release of free fluoride ions also contributed to the increased ore values in these intersection zones. Yttrium values in fluorite taken from a longitudinal traverse of the western ore body, Redburn mine, Rookhope, are plotted in [Fig. 1.] The position of a major vein branch and three cross veins are clearly indicated by yttrium maxima. The cross veins themselves contain up to 2.5 m of low grade fluorspar ore. The exact positions of B and C were unknown previous to the geochemical survey. Similar results have been obtained for several other veins and ore bodies in the area. Clean fluorspar was collected as bulk samples from within 300 mm of the vein wall and, since the vein infilling is simple, with mineral growth from the walls inward, analyses of the samples are considered comparable along the length of the ore body. A number of samples taken from the center of the vein show a

Jan 1, 1975

By V. R. Garfias, A. C. Fernandez

Despite artificial curtailment in all the fields of Mexico during 1937, owing to strikes and other disturbances, the production of crude petroleum aggregated approximately 46,738,000 bbl., showing a substantial increase of about 5,571,000 bbl. over the preceding year. Most of this increase occurred in the Poza Rica area, where, although only two wells were completed during the year, production increased from 14,162,000 bbl. in 1936 to 18,634,000 in 1937. While production in the South fields (Golden Lane) remained practically stationary, the output in the heavy-oil district of the Northern fields showed an increase of 1,930,000 bbl., because production had been considerably curtailed during 1936. Production in the Isthmus of Tehuantepec decreased about 596,000 bbl., owing to labor disturbances. Crude run to stills in local refineries increased from 34,000,000 bbl. in 1936 to 36,650,000 in 1937. Exports of crude and refined products were approximately 22,700,000 bbl., or 500,000 bbl. less than in 1936. Domestic consumption, excluding ships bunkers, reached a total of 20,000,000 bbl., which shows a small increase of 200,000 bbl. over the. previous year. Domestic demand for gasoline is estimated at 3,400,000 bbl. for the year, which represents an increase of 500,000 bbl. over 1936. In all, 60 wells were completed in Mexico during 1937, as compared to 70 in 1936 and 74 in 1935. In proven areas 52 completions resulted in 25 producers and 27 failures. In the Northeastern area near the United States border, five gas wells were drilled, all of which were producers; one of them, in Camargo, came in with a daily production of 20,000,000 cu. ft. of gas. One well, resulting in a failure, was drilled in Las Uvas, Coahuila, and three wells were completed in Quebrache, to the southeast of the heavy-oil district, resulting in two small producers and one failure. TWO more wells drilled in San SebastiBn, east of the Golden Lane, were failures. Fields Northern Fields (Heavy-oil District).—A total of 11 producers and 22 failures was completed in the proven areas of the Northern fields, as compared to 16 producers and 25 failures in 1936. In the Altamira

Jan 1, 1938

By James Hyslop

THE Pittsburgh seam in eastern Ohio has an average thickness of 5 ft and lies almost level Immediately above it is a layer of draw slate about 12 in thick, which normally has little structural strength, and is pulled down or allowed to fall as mining progresses Above the slate is a, variable thickness of roof coal, which in places will stand for the life of the working section and sometimes for the life of a secondary haulage entry The thickness of this roof coal varies from zero to 24 in In general, however, it does not provide a satisfactory roof, and usually is supported or pulled down About it is a mass of shale, soapstone and clay, of quite variable thickness, usually running from 5 to 8 ft and above this is a stratum of hard blue limestone, which provides a permanent roof Where entries are to be used for less than five years, the roof usually can be supported by wood or steel crossbars, but if they are to be used for a longer time, roof support is a serious problem All the roof material below the limestone disintegrates when exposed to air or moisture, and in a few years falls out between and over the crossbars Where this material is removed for a considerable height above the coal, the ribs scale and thus contribute to a further collapse of the roof As the height of the entry increases, cost of timbering is greatly increased, a problem that always is encountered where old entries are recovered or repaired METHODS During the last six years the Hanna Coal Co has used gunite for roof protection in mine entries Two general methods of guniting are practiced The first consists of the application of a I-in coating of unreinforced material This application does not provide any appreciable structural strength, and serves principally to protect the strata from exposure to air and moisture With the other method a coat at least 2 in thick is applied and provided with suitable reinforcing, which provides a structural strength proportional to the thickness of the coat and the reinforcing used The first method is adopted as a general practice, modified only where additional support is required "Gunite" is a mixture of cement, sand and water * The cement and sand are thoroughly mixed and screened before being fed into the hopper of a cement gun After the hopper lid is closed, compressed air is applied to force this dry mixture through the hose line to the nozzle, where the quantity of water needed to effect the proper hydration of the cement is added The coating is dense, and stronger than poured concrete

Jan 1, 1941

By Leonid Bryner

For many years, geologists have inferred a connection between the evolution of the earth's crust and ore deposition, a connection coming under the heading of metallogeny. In recent years the concept of metallogeny has assumed major importance in the exploration planning of Russian geologists in their quest for new mineral sources. As defined by Radkevich, metallogeny is "the science which studies the laws governing the distribution of ore deposits in the earth's crust." However, since it can be argued that metallogeny does not contain enough certitude to be classified as a "science," it would be more appropriately defined as the study of metallogenic provinces, and metallogenic epochs.

Jan 6, 1963

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, III., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four concentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade fluorspar.2,3 Although fluorspar had been floated in Canada in 1921 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Mines6 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1947

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, III., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four concentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade fluorspar.2,3 Although fluorspar had been floated in Canada in 1921 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Mines6 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1947

By O. Mellgren, A. M. Gaudin, P. L. De Bruyn

The adsorption density of ethyl xanthate on pyrite was determined as a function of xanthate concentration. Surface preparation of the mineral appears to have asafunctionsome effect on the subsequent adsorption process, A monolayer of xanthate on the surface is exceeded only in presence of oxygen. The effect of OH- , HS- (and x and CN- S=)and on the amount of xanthate adsorbed was investigated. Competition between OH- and X- (xanthate) ions for specific adsorption sites is indicated over a wide pH range. IN the flotation of sulfide ores, xanthates are most commonly used to prepare the surface of the mineral to be floated so that attachment to air takes place. The quantity of agent required to make the mineral hydrophobic is usually very small, of the order of 0.1 to 0.25 lb per ton of mineral. Details of the mechanism of pyrite collection are for the most part unsettled. Adsorption of collector has long been believed to involve an ion exchange mechanism as demonstrated for galena' and for chalcocite.2 In the work on chal-cocite it was also demonstrated that a film of xanthate radicals unleachable in solvents that dissolve alkali xanthates, copper xanthate, or dixanthogen was formed at the surface of the mineral. The unleachable product increased with increasing addition of xanthate up to a maximum corresponding to an oriented monolayer of xanthate radicals. Pyrite is extremely floatable with xanthate if its surface is fresh.9 ut the floatability decreases rapidly as oxide coatings increase in abundance. Pyrite shows zero contact angle when in contact with ethyl xanthate solution at pH higher than about 10.5;4 at neutrality, a contact angle of 60" is obtained at a reagent concentration of 25 mg per liter. Alkali sulfides and cyanides are pyrite depressants. In this study of pyrite collection the writers have sought to relate measured xanthate adsorption to the method used in preparing pyrite, to the presence or absence of oxygen, to concentration of hydroxyl, hydrosulfide, sulfide, and cyanide ions. The principal experimental tool has been radioanalysis," " using xanthatcx marked with sulfur 35. Experimental Materials Pyrite: Unlike most sulfides, pyrite is a poly-sulfide. The structure given by Bragg7 resembles that of sodium chloride, the iron atoms corresponding to the position of sodium and pairs of sulfur atoms corresponding to the position of chlorine. The edge of the unit cell in pyrite is 5.40 A and in halite 5.63 A. The S-S distance in pyrite is 2.10 A; the Fe-S distance, 3.50 A: and the Fe-Fe distance, 3.82 A. Natural pyrite from Park City, Utah, was used in this investigation. Pyrite 1 was obtained by hand picking pure crystals. Pyrite 2 and Pyrite 3 were obtained from finer textured crystalline material containing inclusions of silicates. The same cleaning technique was utilized for the preparation of Pyrite 2 and Pyrite 3, whereas a different cleaning technique was used for Pyrite 1. Pyrite 1 was prepared as follows: The crystals were ground in a porcelain ball mill and the 200/400 mesh fraction was separated by wet screening with distilled water, followed by washing for 1 hr with deoxygenated distilled water acidified with sulfuric acid to pH 1.5. The acid was removed by rinsing with deoxygenated distilled water on a filter until a pH of 6.0 was reached in the effluent. This filtration was carried out under nitrogen. The sample was then dried in a desiccator under nitrogen. The period of time for which this pyrite sample was in contact with water containing oxygen was about 4 hr. The specific surface as determined by the BET gas adsorption method was 582 cm2 per g. Final material assayed 53.12 pct sulfur and 46.5 pct iron (theoretical, for FeS,: S, 53.45 pct; Fe, 46.55 pct). After crushing, Pyrite 2 and Pyrite 3 were washed with 1 M HCl. rinsed, and fed to a laboratory shakinq table to remove the small amount of silicates. The concentrate obtained was ground in a laboratory steel ball mill. The 200/400 mesh fraction was separated by classification in a Richards hindered settling tube. This fraction was then given a final wash with 0.1 M HCl and deoxygenated water was filtered through the sample. The final effluent showed a conductivity equivalent to that of a solution having a salt concentration of 0.3 ppm. Aqueous hydrogen sulfide solution was then added to the sampln (about 100 ml saturated H,S solution to about 1000 g pyrite under a few hundred milliliters of water) which was stored wet under nitrogen. The sample stored in this manner showed no indication of formation of iron oxides, whereas iron oxides appeared

Jan 1, 1957

By H. T. Kennedy

The fact that intrusion of water into oil wells can be prevented by treating the sand adjacent to the well seems to have been only recently recognized. Swan1 mentions the process of solidifying naphthalene in strata. R. Van A. Mills2 recommends the use of materials such as sodium silicate and sodium carbonate, which react with oil-field water to form solid plugging agents. When a well is drilled in a new field the oil sands are found essentially devoid of water (Fig. 1). Unless a completely impermeable break exists over wide areas in the field, no water is found above the lower limit of the oil zone and no oil is found below the upper limit of the water zone. After considerable oil has been taken from the well, however, it is almost universal experience that water intrusion occurs. This intrusion may be of two kinds. The water may follow a path parallel to the bedding planes of the producing formation through loose streaks in the pay sand, as shown in Fig. 2, or the water level of the field may rise and enter the well by coning (Fig. 3). Water entering from the side is called "edge water," and that coming in from the bottom is called "bottom water.'' Effectiveness of any method for shutting off water depends not only on the effective treatment of the sand adjacent to the well but on

Jan 1, 1936