Search Documents

By J. B. Clemmer, F. D. DeVaney, H. A. Doerner

Production of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaC03) and dolomite (MgCO3. CaC03). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedra1 crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent SiO2, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 SiO2 and 6.5 R2O3. The percentage reported as R2O3 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe2O3, A1203 and TiO2. The sorted magnesite product is not the best grade. even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1943

By J. H. East, E. R. Maize

INTRODUCTION PROBABLY no other type of equipment is now being introduced into American underground mines about which less is known and about which there is more misinformation than the Diesel mine locomotive. Any equipment installed underground brings with it hazards that were not present before, and it is the purpose of this paper to show that Diesel-powered equipment can be used with safety in underground mining if certain feasible but very important precautions are taken. Diesel locomotives are not new in underground mining, since they have been used successfully in European mines for at least 19 years, but their use in American mines is exceedingly limited; so far as is known, only five Diesel mine locomotives are operating at present in United States mines. Diesel locomotives were permitted underground in Great Britain for the first time in 1939, and the rapid increase in the number in use in those mines, testifies to their safety and efficiency. More than 1300 Diesel mine locomotives are in use in European mines, according to the latest statistics; these locomotives are employed in coal, iron, lead-zinc and mercury mines. So far as is known, the Diesel mine locomotive has not yet caused an explosion or mine fire, and has not been the cause of any fatalities from toxic gases in the mines in which it has been used. ADJUSTMENTS OF DIESEL ENGINES FOR UNDERGROUND USE A Diesel engine adjusted to work in an underground mine should not be confused with the same engine adjusted for use outside the mine. Adjustment of the air:fuel ratio for engines that are used on the surface is intended to give the maximum fuel economy, and little or no attention is given to the chemical composition of the exhaust gas produced. Many such engines are poorly adjusted and perhaps poorly maintained, with the result that the engine emits smoke in quantity as well as the disagreeable odor familiarly associated with Diesel engines. The air:fuel ratio in the case of Diesel engines operated on the surface is generally around 15:1; that is, 15 lb of air to burn 1 lb of fuel. Diesel engines adjusted to work underground usually have an air:fuel ratio of about 20:I, as at this ratio the minimum quantity of toxic gases is given off in the engine exhaust. Diesel engines operated underground must be maintained in better condition than similar engines used on the surface; otherwise, the smoke emitted in the exhaust becomes objectionable if not unendurable. Practically normal air is required for safe operation of Diesel engines underground or in confined places; failure to provide virtually normal air for Diesel engine operation is almost certain to result in trouble. Bureau of Mines engineers have determined that the air in which a Diesel operates in confined places should contain less than 1/2 pct of carbon dioxide and at least 20 pct of

Jan 1, 1947

By J. H. East, E. R. Maize

Probably no other type of equipment is now being introduced into American underground mines about which less is known and about which there is more misinformation than the Diesel mine locomotive. Any equipment installed underground brings with it hazards that were not present before, and it is the purpose of this paper to show that Diesel-powered equipment can be used with safety in underground mining if certain feasible but very important precautions are taken. Diesel locomotives are not new in underground mining, since they have been used successfully in European mines for at least 19 years, but their use in American mines is exceedingly limited; so far as is known, only five Diesel mine locomotives are operating at present in United States mines. Diesel locomotives were permitted underground in Great Britain for the first time in 1939, and the rapid increase in the number in use in those mines testifies to their safety and efficiency. More than 1300 Diesel mine locomotives are in use in European mines, according to the latest statistics; these locomotives are employed in coal, iron, lead-zinc and mercury mines. SO far as is known, the Diesel mine locomotive has not yet caused an explosion or mine fire, and has not been the cause of any fatalities from toxic gases in the mines in which it has been used. Adjustments of Diesel Engines foR Underground Use A Diesel engine adjusted to work in an underground mine should not be confused with the same engine adjusted for use outside the mine. Adjustment of the air:fuel ratio for engines that are used on the surface is intended to give the maximum fuel economy, and little or no attention is given to the chemical composition of the exhaust gas produced. Many such engines are poorly adjusted and perhaps poorly maintained, with the result that the engine emits smoke in quantity as well as the disagreeable odor familiarly associated with Diesel engines. The air:fuel ratio in the case of Diesel engines operated on the surface is generally around 15:1; that is, 15 lb of air to burn I lb of fuel. Diesel engines adjusted to work underground usually have an air:fuel ratio of about 20:1, as at this ratio the minimum quantity of toxic gases is given off in the engine exhaust. Diesel engines operated underground must be maintained in better condition than similar engines used on the surface; otherwise, the smoke emitted in the exhaust becomes objectionable if not unendurable. Practically normal air is required for safe operation of Diesel engines underground or in confined places; failure to provide virtually normal air for Diesel engine operation is almost certain to result in trouble. Bureau of Mines engineers have determined that the air in which a Dicsel Operates hi confined places should contain less than % pct of carbon dioxide and at least 20 pct of

Jan 1, 1949

By Marshall B. Standing, Donald L. Katz

Density data are reported on 16 saturated hydrocarbon vapors at Pressures ranging from 1000 to 8220 Ib. per sq. in. and at temperatures ranging from 35° to 250°F. These data have been used to extend the compressibility-factor chart for natural gases up to 10,000 lb. per sq. in. The relatively large quantity of high-boiling constituents present in high-pressure vapors in equilibrium with crude oils makes it necessary to include in the analysis of the gas the molecular weight, density, and possibly boiling range of the heptanes and heavier fraction. Relationships have been presented by which the density of gases may be obtained directly from the temperature, pressure, and gas gravity provided the gases have a common source or are similar in composition. Introduction The densities of natural gases are necessary in many engineering in in petroleum production and utilization, Gas reserves, changes in reservoir pressure, gradients in gas wells, metering of gases, pipeline flow, and compression of gases are typical problems requiring the density of the gas. A decade ago, engineering computations used ideal gas laws with deviations up to 500 Ib. per sq. in.4 Recent discoveries of pools having Pressures UP to 7500 lb. Per sq. in., and installation of pressure-maintenance and recycling plants, have increased the need for data On gas density at high pressures. Methods of Computation The accepted method of computing the density or specific volume of natural gases is the use of the ideal gas law corrected by a compressibility factor. The method proposed by Kay7 of correlating compressibility factors for gaseous mixtures on pseudocritical properties5 appears to be satisfactory for natural gases.2 The meth-me-compressibility factor has been shown to deviate systematically from the behavior of natural gases2 and a chart giving these corrected factors is available. A method of computing specific volume of gaseous mixtures from partial molal volumes has been reported by sage and Lacey.8 Complete data for the computation are not yet available for all hydrocarbon gases. Most- of the reported data on gas densities have been in the single-phase region removed from the dew point or saturation condition. Since most gases in the reservoir Or while on contact with liquid '''ring flow are saturated, the determination of densities under conditions of saturation is particularly important. Although there is no reason to believe that the saturated gases differ in behavior from those consider. ably removed from their dew points, the usual experimental determinations find difficulty on approaching the dew-point conditions, This paper reports the density of I6 saturated gases in equilibrium with crude oils. The relationships developed to compute the density of gases to high pressure' have been modified and enlarged. A simpli-fied method of obtaining gas density is presented in the Form of charts, which apply for specific groups of gases.

Jan 1, 1942

By A. M. Adair

The effect of cathodically charging zone-refined iron with hydrogen and the resultant yield stress-grain size relationship has been investigated by tensile testing at -31°C. The resulting Petch plots (using a least-squares analysis) reveal a significant reduction in the slope and an increase in the intercept for specimens cathodically charged with hydrogen, regardless of whether the hydrogen is present during testing or is removed by evacuation. Other than surface blistering, the major effect of cathodically charging this material is to create occasional grain boundary cracks and thus presumably a large number of free dislocations at grain boundaries. These results are consistent with the hypothesis that the slope of the Petch plot is related to the stress required to activate dislocation sources at or near pain boundaries. While there is no significant effect of the presence of hydrogen on the lower yield stress of this material, the ductility is considerably reduced. After hydrogen removal by evacuation, the ductility recovers substantially and almost complete recovery of ductility is experienced by the smaller grain size specimens. THE influence of hydrogen on the mechanical properties of ferritic materials has received much attention throughout the history of the metallurgy profession. This interest has stemmed from the obvious importance of preventing the catastrophic failure of parts in service, and from the desire to determine what mechanism is responsible for the observed behavior. The various mechanisms proposed for hydrogen em-brittlement have been discussed in detail by Tetel-man,'who concludes that a combination of the applied stress and hydrogen pressure within voids best accounts for the many experimental observations reported. From a quite reasonable correlation of the strain aging and delayed-failure behavior of a variety of materials,2-7 Troiano and coworkers are of the opinion that the delayed-failure mechanism (slow strain rate embrittlement as well) is better explained as a lattice effect; solute elements diffuse to regions of high triaxial stress, form uncondensed atmospheres there, and effect a reduction in the cohesive strength of the lattice. Since hydrogen yield points8,9 have been observed in ferritic materials, and since the hydrogen embrittlement process may be related to strain aging, one further contribution to embrittlement could be hydrogen-dislocation interactions which make crack blunting by plastic deformation a more difficult process. The etch" relationship offers a means of comparing the relative ease of initiating and propagating plastic deformation in metals and alloys. In the present study, this relationship was used to compare the behavior of zone-refined iron in three conditions: uncharged, cathodically charged with hydrogen, and cathodically charged with hydrogen and evacuated. These Petch plots and the observed ductility parameters allowed a separation of the effects of the very presence of hydrogen and the act of cathodically charging hydrogen into this material. MATERIALS AND EXPERIMENTAL PROCEDURE An ingot of zone-refined iron was obtained from Battelle Memorial Institute which contained the following (typical) interstitial impurities in ppm: carbon, 10 * 5; nitrogen, 1; oxygen, 22; hydrogen, 0.9. The ingot was cold-reduced to a 1/2-in.-sq cross section, recrystallized 1 hr at 575°C, and then straight-rolled to a thickness of about 0.105 in. Tensile specimens were milled from the strip having a 1-in. gage length

Jan 1, 1967

By A. D. Marlin, A. J. Gentile, E. F. Jordan

Metallurgical changes in SAE 52100 ball-bearing components resulting from overload testing are described. Changes in microstructure, hardness, and resiclctal stresses crre discussed zuitlz re.ference to material cleanliness obtained by various steel-melting practices and are compared with work by otlzer investigators. Evidence is presented to show that the initialion and development of microstruc-tural alterations are characterized by two separate reactions: the appeavance of a "dark etchingJ' constituent, and "gray lines" or a light etclzing constituent. The dependency of these tzvo reactions on material cleunliness, running tirne, and contact stresses is discussed and a failure mode related to material cleanliness and microstructural transformation is proposed. THE study of ball- and roller-bearing contact fatigue has been paced by a strong emphasis on bears ing application performance. Particular attention has been paid to conditions that effect the spalling-type failure that is characteristic of rolling contact fatigue in through-hardened components. Some of the conditions investigated are lubrication and atmosphere,1-3 material characteristics and finish,475 and speed and design fa~tors."~ A typical spalling-type failure is shown in Fig. 1. The arrow shows the motion of the ball relative to the inner-ring race surface. The leading edge of the spall is usually sharper than the trailing edge. The race surface near the trailing edge also shows small dents caused by debris from the spall. In this type of testing very little metallurgical investigation is done on failed bearings. Emphasis is placed on test conditions and statistical analyses of endurance data. More basic work has been done relating micro-structural changes to fatigue performance. Dyer" and Wood, Cousland, and sargant9 have used mostly simple materials, such as single crystals and single-phase polycrystalline specimens, under simple alternating strain to identify a systematic process of fatigue damage. drutowski" was concerned primarily with the relationship between steel structure, contact stress, and energy losses in rolling contact. dones11 and Bush, Grube, and Robinson12 utilized changes in microstructure and residual stress in overload-tested rolling contact elements as a means of investigating the fatigue process. Work is being done on an ASME-sponsored contract,13 using both simple and complex materials, but there is still a long way to go before such theories as pore and void growth in simple structures can be applied to the relatively complex bearing steel microstructure. The purpose of this paper is to report on an investigation into the effect of steel cleanliness on the structural alteration and residual stress changes found in overload-tested ball bearings. Using these results and those of previous investigators, we will propose probable failure mechanisms in both overload- and normal load-tested ball bearings.14,15 PROCEDURE Ball bearings? 3208 size, were fabricated from SAE 52100 steel obtained by five different melting practices. The melting practices, chemistry, and inclusion ratings for the five lots of steel are summarized in Tables I and 11. The nonmetallic inclusion ratings were determined by the Jernkontoret method described in ASTM E45-51 Method A. This technique consists of microscopically examining a series of polished samples taken from specified locations in the ingots, billets, or bars. Each sample is surveyed at XlOO magnification and the inclusion types and sizes are compared to standard fields. Because of the nature of these ratings all values in Table I1 are rounded to the nearest half. The elec-

Jan 1, 1965

By C. E. Webber

The economical recovery of the valuable constituents from the effluent of gas-con-densate wells has developed into a problem of balancing the cost of recovery against the cost of compressing the residual gas back into the formation. A possible method of extracting the gasoline and distillate from the natural gas is by oil absorption at high pressures. In order to design and evaluate an absorption plant, fundamental data on the composition of the coexisting hydro- carbon vapor and liquid phases at various temperatures and pressures are essential. A review of the literature indicated that the necessary data for the design of such plants are lacking. The nearest approach to desired published data is that of Katz and Hackmuth,~ who experimentally deter-mined the composition of the coexisting vapor and liquid phases in a natural gas-crude oil system at pressures up to 3000 lb. per sq. in. and at temperatures from 40' to zoo°F. This paper presents the results of the experimental determination of the equilib-rium distribution of the hydrocarbons methane through hexane between natural gas and a typical absorber oil. The ranges of temperature and pressure chosen were from 33' to r8oUF. and from 100 to 5000 lb. per sq. inch. Materials The absorber oil was a typical naturally occurring, Straw-colored distillate that had previously been steam-distilled to an initial boiling point of 300 F. The physical and chemical properties, including the results of an Engler distillation, are presented in Table I. A large volume of this oil was obtained and it was used throughout the complete set of experiments. Table i.—Properties of the Absorption Oil Gravity .......................... . . 32.5' A.P.1. Molecular weight by benzene freezing- point depression.................. 183 Viscosity, poises; at 100°F........... 0.0a80 At 200°F...................... 0.0102 Composition, PeR Cent Aromatics........ 24.0 Naphthenes..... 36.7 unsaturates,Aromatics...... .I24.00.3 1 Parafins Naphthenes.....36.7 39.o EngLeR Distillation Per Cent /ncg. F. Per Cent Dez. P. Initial boilins rmint.. 300 I 60....... 523 5.................. 402 I 70....... 538 10.................. 421 180....... 557 20.................. 462 90....... 570 30.................. 480 1 95....... 623 40.................. 49 .................1 511 Residue, z .o per cent; loss, 0.3 per cent. See refrence I. The n-hexane was obtained from the Ohio Chemical and Manufacturing Co., Cleveland, Ohio. This liquid had a boiling range of from 149" to 152.6'F., with a density of 0.667 at 60°F. and a molecular weight of 85 by benzene freezing-point depression. The propane, isobutane, wbu-tane, isopentane and n-pentane were ob-ta,ined from the Philgas Department of the Phillips Petroleum Co. Certified analyses of these compounds showed their purity to be in excess of 99.5 per cent and they were riot further purified.

Jan 1, 1941

By C. E. Webber

The economical recovery of the valuable constituents from the effluent of gas-con-densate wells has developed into a problem of balancing the cost of recovery against the cost of compressing the residual gas back into the formation. A possible method of extracting the gasoline and distillate from the natural gas is by oil absorption at high pressures. In order to design and evaluate an absorption plant, fundamental data on the composition of the coexisting hydro- carbon vapor and liquid phases at various temperatures and pressures are essential. A review of the literature indicated that the necessary data for the design of such plants are lacking. The nearest approach to desired published data is that of Katz and Hackmuth,~ who experimentally deter-mined the composition of the coexisting vapor and liquid phases in a natural gas-crude oil system at pressures up to 3000 lb. per sq. in. and at temperatures from 40' to zoo°F. This paper presents the results of the experimental determination of the equilib-rium distribution of the hydrocarbons methane through hexane between natural gas and a typical absorber oil. The ranges of temperature and pressure chosen were from 33' to r8oUF. and from 100 to 5000 lb. per sq. inch. Materials The absorber oil was a typical naturally occurring, Straw-colored distillate that had previously been steam-distilled to an initial boiling point of 300 F. The physical and chemical properties, including the results of an Engler distillation, are presented in Table I. A large volume of this oil was obtained and it was used throughout the complete set of experiments. Table i.—Properties of the Absorption Oil Gravity .......................... . . 32.5' A.P.1. Molecular weight by benzene freezing- point depression.................. 183 Viscosity, poises; at 100°F........... 0.0a80 At 200°F...................... 0.0102 Composition, PeR Cent Aromatics........ 24.0 Naphthenes..... 36.7 unsaturates,Aromatics...... .I24.00.3 1 Parafins Naphthenes.....36.7 39.o EngLeR Distillation Per Cent /ncg. F. Per Cent Dez. P. Initial boilins rmint.. 300 I 60....... 523 5.................. 402 I 70....... 538 10.................. 421 180....... 557 20.................. 462 90....... 570 30.................. 480 1 95....... 623 40.................. 49 .................1 511 Residue, z .o per cent; loss, 0.3 per cent. See refrence I. The n-hexane was obtained from the Ohio Chemical and Manufacturing Co., Cleveland, Ohio. This liquid had a boiling range of from 149" to 152.6'F., with a density of 0.667 at 60°F. and a molecular weight of 85 by benzene freezing-point depression. The propane, isobutane, wbu-tane, isopentane and n-pentane were ob-ta,ined from the Philgas Department of the Phillips Petroleum Co. Certified analyses of these compounds showed their purity to be in excess of 99.5 per cent and they were riot further purified.

Jan 1, 1941

By Carlton Beal

This paper presents useful charts for conversion of various viscosimeter units into centipoises and graphically summarizes published investigations of the viscosity of air, water and natural gas at high temperatures and pressures. Where possible, charts and correlations were constructed to cover a range of temperature (60°F. to 300°F.) and pressure (14.7 lb. per sq. in. abs. to 8000 lb. per sq. in. gauge) encountered in oil fields. Correlation charts, for the purpose of predicting crude oil viscosity and solubility behavior at oil field temperatures and pressures, were constructed from an analysis and correlation of 1332 viscosity and solubility observations from 953 crude oil samples taken from 747 oil fields. Of these fields, 501 are in the United States, including 75 in California. Of the 1332 observations, 1215 were viscosity values, including 786 of gas-free crude oil, 351 of oil saturated with gas, and 78 under-saturated with gas at pressures above the bubble point. Results show that crude oil viscosity at various reservoir conditions can be predicted with average deviations varying from 24.2 per cent for gas-free crude oil to as little as 2.7 per cent for undersaturated crude oil "above the bubble point." The solubility of crude oil may be predicted from oil gravity and saturation pressure with an average deviation of 22.0 per cent from observed values. In conclusion, it is shown that the viscosity of a gas and gas-saturated crude oil may be predicted within the accuracy of most reservoir computations. Viscosity is a measure of flow resistance; common units are in centipoises (cp.). The object of this report is to present conversion charts and simplified 'correlation charts showing the viscosity behavior of air, water, gas and crude oil and gas-saturated crude oil under oil field temperatures and pressures, which have been known to be as high as 300°F. and 8000 Ib. per sq. in. gauge under subsurface conditions. The viscosity of a liquid or gas is important because it is a measure of its fluidity, or its ability to flow through pipe lines or oil sands. Viscosity of air has become important because it is being used in secondaryl,2 recovery projects. The viscosity of natural gas and water at reservoir conditions is useful because they are almost universally associated and produced with crude oil. The viscosity of gas-saturated crude oil at reservoir pressures and tem peratures is of particular value in making estimates of oil reserves3 and rate of oil recovery from flush pools when production decline data are limited. Instruments Used to MeasuRe Viscosity There are many types of viscosimeters,4 and the instruments most commonly used to measure the atmospheric viscosity of liquids at moderate temperatures and their practical working ranges have been deScribed5,6 in detail. Fig. I and Fig. 2 are viscosity conversion charts which have

Jan 1, 1946

By Carlton Beal

This paper presents useful charts for conversion of various viscosimeter units into centipoises and graphically summarizes published investigations of the viscosity of air, water and natural gas at high temperatures and pressures. Where possible, charts and correlations were constructed to cover a range of temperature (60°F. to 300°F.) and pressure (14.7 lb. per sq. in. abs. to 8000 lb. per sq. in. gauge) encountered in oil fields. Correlation charts, for the purpose of predicting crude oil viscosity and solubility behavior at oil field temperatures and pressures, were constructed from an analysis and correlation of 1332 viscosity and solubility observations from 953 crude oil samples taken from 747 oil fields. Of these fields, 501 are in the United States, including 75 in California. Of the 1332 observations, 1215 were viscosity values, including 786 of gas-free crude oil, 351 of oil saturated with gas, and 78 under-saturated with gas at pressures above the bubble point. Results show that crude oil viscosity at various reservoir conditions can be predicted with average deviations varying from 24.2 per cent for gas-free crude oil to as little as 2.7 per cent for undersaturated crude oil "above the bubble point." The solubility of crude oil may be predicted from oil gravity and saturation pressure with an average deviation of 22.0 per cent from observed values. In conclusion, it is shown that the viscosity of a gas and gas-saturated crude oil may be predicted within the accuracy of most reservoir computations. Viscosity is a measure of flow resistance; common units are in centipoises (cp.). The object of this report is to present conversion charts and simplified 'correlation charts showing the viscosity behavior of air, water, gas and crude oil and gas-saturated crude oil under oil field temperatures and pressures, which have been known to be as high as 300°F. and 8000 Ib. per sq. in. gauge under subsurface conditions. The viscosity of a liquid or gas is important because it is a measure of its fluidity, or its ability to flow through pipe lines or oil sands. Viscosity of air has become important because it is being used in secondaryl,2 recovery projects. The viscosity of natural gas and water at reservoir conditions is useful because they are almost universally associated and produced with crude oil. The viscosity of gas-saturated crude oil at reservoir pressures and tem peratures is of particular value in making estimates of oil reserves3 and rate of oil recovery from flush pools when production decline data are limited. Instruments Used to MeasuRe Viscosity There are many types of viscosimeters,4 and the instruments most commonly used to measure the atmospheric viscosity of liquids at moderate temperatures and their practical working ranges have been deScribed5,6 in detail. Fig. I and Fig. 2 are viscosity conversion charts which have

Jan 1, 1946

By Nelson Severinghaus

Mineral fillers have been defined as inert materials that are included in a composition for some useful purpose. Because this definition and the scope of this review are not specific-indeed, exceptions abound-accurate total statistics are unavailable. One source estimates the total production in the United States in 1979 at 11.3 Mt (12.5 million st) valued at $534 million, averaging $49.19 per ton. Included are a broad group of minerals-asbestos, barite, bentonite, ground limestone and dolomite, clays, diatomite, feldspar, micas, silica, talc. Additional references will be made to synthetic mineral-derived fillers such as aluminum hydrate, precipitated calcium carbonate, and pyrogenic and precipitated silicas and silicates. A section on related uses at the end of this chapter covers absorbents and filters. Mineral fillers can be included in compounds to accomplish a variety of final results. Hardness, brittleness, impact strength, compressive strength, softening point, fire resistance, surface texture, electrical conductivity, and a host of other physical characteristics may be modified by the inclusion of fillers. These effects are the result of properties of the fillers, including chemical activity, hardness, particle size, shape and distribution, surface structure, color, density, and refractive index. To facilitate an overview of the mineral filler industry, this chapter will review the general usage of fillers, the inherent characteristics that intensify their utilization, and similarly their manufactured characteristics. Major using industries will then be examined in detail. Specific information on deposits and processing for industrial minerals will be found in the appropriate commodity chapter. All of these same minerals have additional significant uses based on their chemical composition or other characteristics. References will be found in other use chapters and summarized in commodity chapters. The chart in Table 1, updated from the 4th edition of Industrial Minerals and Rocks, illustrates the major mineral fillers (both natural and manufactured) and their more important end uses. Use of Mineral Fillers Archaeologists have found that more than 5000 years ago, bitumen used for mortar and waterproofing contained mineral contaminants that acted as fillers. Since that time man has added mineral products to compounds to improve certain characteristics. Perhaps the most common objective of filler usage is reduction of cost of the end product. Certainly the inclusion of a filler that costs 2¢ per 0.45 kg (lb) will reduce the cost of a plastic product whose resin costs 50¢ per 0.45 kg (lb). But the decision to use a specific filler is not that simple. It may "soak up" binder, making a compound more viscous and perhaps preventing its flow into a mold as an injection molding compound, but similarly will give good anti-sag characteristics to putty, caulking compound, or undercoating. Fillers may be incorporated to modify: 1) Cost 2) Physical characteristics 3) Flow characteristics 4) Fire resistance 5) Density 6) Heat conductivity 7) Color or brightness and opacity 8) Hardness, brittleness, impact strength 9) Deformity, viscosity, softening point 10) Processing problems 11) Electrical conductivity 12) Surface texture 13) Thermal expansion characteristics 14) Abrasion resistance

Jan 1, 1983

By S. J. Burns, W. W. Webb

The dislocation arrangements formed during unsteady propagation of cleavage fractures on (010) planes in LiF have been investigated by high-resolution etch-pit techniques and by X-ray diffraction topogvaphy. In impurity-hardened crystals, cracks propagating in any direction on (010) planes at velocities of about 103 cm per sec are usually accompanied by light plastic deformation which is enhanced wherever the crack is allowed to hesitate. Dislocations with [011] type Burger's vectors are often formed looped around the crack tip. They are dragged along with the crack tips leaving edge dislocations lying nearly parallel with the clearage surface about 5µ from it. These dislocations are easily overlooked since they may initially intersect with the cleavage surface infrequently and later may disappear from the crystals due to image forces during aging at room temperature. Although the plastic work associated with these dislocations is only comparable with the reversible (010) surface energy, an instability in crack propagation appears due to a limit of the velocity with which dislocations can be dragged along with the crack. Transition to a fully brittle nonplastic fracture mode occurs when the crack velocity exceeds the velocity with which dislocations can be moved by the stress field of the crack. TRANSITIONS between brittle and ductile modes of fracture appear to be common processes in the behavior of materials in which the flow stress is close to the stress at which brittle cracks can propagate. High-strength engineering alloys fit into this category and the transition from ductile to brittle modes of crack propagation may be associated with catastrophic failures in these important materials. The methods of theoretical mechanics indicate the geometrical conditions in which these processes may occur but the detailed mechanisms controlling the generation of dislocations in the initiation of the plastic mode and the process by which the loss of plasticity occurs on transition to the brittle mode are not yet clear. Since these mechanisms are not amenable to direct observation in engineering alloys we have chosen a semi-ductile alkali halide LiF as a model system in which to observe transition mechanisms between plastic and brittle modes of crack propagation. Cleavage cracks in this system are known to undergo a plastic-elastic transition at velocities between 103 to 104 cm per secl and dislocation configurations in LiF are amenable to study by optical-microscopic observation of dislocation etch pits2 and by X-ray diffraction topography.3 We have been able to identify a dislocation mechanism responsible for the transition from brittle to slightly plastic modes of crack propagation in LiF. A model based on this mechanism permits calculation of the critical crack-propagation velocity for this transition and indicates the importance of the stress dependence of dislocation velocity in determining the critical crack velocity. Of course, this model cannot be carried directly over to more complex materials but it is quite possible that its qualitative features are generally applicable. Dislocations intersecting fresh cleavage surfaces in LiF were reported by Gilman,4 by Forty,5 and by Wash-burn et a1.6 Such dislocations were construed to have been nucleated where the cleavage crack hesitated or stopped, near stress concentrators, such as cleavage steps, on the crystal face. The loci of such dislocations deposited On the cleavage plane in bands were called "stop lines" or "deformation zones". Gilman, Knudsen, and walshl measured the velocity of cleavage cracks in lithium fluoride by evaporating thin resistive strips on the crystal side and recording

Jan 1, 1967

By Michael Perch, Charles C. Russell

Nearly 75 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank' standardized by the American Society for Testing Materials. Although this method of classification has been an American stand¬ard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1944

By Michael Perch, Charles C. Russell

Nearly 75 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank1 standardized by the American Society for Testing Materials. Although this method of classification has been an American standard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1942

By Michael Perch, Charles C. Russell

Nearly 7 5 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank1 standardized by the American Society for Testing Materials. Although this method of classification has been an American standard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1943

By Michael Perch, Charles C. Russell

Nearly 7 5 per cent of the total coke production in the United States in 1940 was consumed in blast furnaces. In 1939 the percentage was 69.9, and in 1938 it was 61.3. To produce a net ton of pig iron 1757 lb. of coke was required in 1940 and 1760 lb. in 1939. These figures indicate how dependent the production of pig iron is upon the production of coke. The rate of iron production is in some measure influenced by the physical and chemical characteristics of the coke. Blast-furnace operators believe that the physical properties of coke profoundly influence the operation of the furnace. Although it is true that coke of a wide variety of physical properties is used in American blast furnaces, the periodic fluctuation of these properties is one of the causes of irregularity of blast-furnace operation. The purpose of this paper is to present a broad picture of the physical properties of by-product coke that are generally considered to be important by coke-oven and blast-furnace operators. Effects of the kind of coal used, the preparation of the coal, the rate of coking, and other factors will be considered. Of all these variables, the kind of coal used is by far the most important. In this discussion use will be made of the method of coal classification by rank1 standardized by the American Society for Testing Materials. Although this method of classification has been an American standard for several years, it has not been given the attention it deserves, especially in connection with the selection of coal for production of coke. Despite the fact that many producers of blast-furnace coke are limited to some particular source or sources of coal, a good understanding of the principles involved in setting up the standard method of classification may lead to a better appreciation of the causes of changes in coke characteristics. Furthermore, where it is necessary to select new coals as a substitute for the original supply, this method of classification can be of great assistance. The data presented have been gathered from many sources, but no attempt has been made to cover the vast literature. Instead, some of the more important data have been selected to show how coals and their carbonization affect some of the physical properties of coke. It must be emphasized that generalizations concerning the behavior of coking coals are presented and that individual coals may vary widely from the specific behavior depicted. Nevertheless, it is believed that the data illustrate certain typical behaviors. Neither was it possible to cover completely all the factors involved; for example, the macroscopic constituents of coal are believed to have important effects on the physical properties of coke, but since there is little information available for such study, and since vitrain, clarain, and durain are neither

Jan 1, 1943

The annual meeting of the Woman's Auxiliary was held on February 19, at 10 a. m. The president, Mrs. Sidney Jennings, said in her greeting "it is a matter of congratulation that during the past year when the demands upon women for work of all kinds has been so large our membership has grown from the 50 enrolled at the first meeting a year ago to over 300 today. Some women, when. asked to join the organization, say that they are doing so much work in other ways that they have no time for work in a new organization, but the director for Canada struck the right note in her report when she told us of the splendid work the wives of mining engineers are doing in Canada, as individuals and as leaders and members of various organizations doing patriotic work. We do not want to divert such women from the work they are now doing, but we do want them to enroll as members of the Woman's Auxiliary and let us know what they are doing, that they play give inspiration to others." Reports were made by the directors of the following sections: Canada, Chicago, Colorado, Columbia, New York, Puget Sound and St. Louis, in some of which sections excellent progress has been made in food conservation, foreign war relief, including the adoption of fatherless French children, and in work for our own engineering regiments. These reports were read, accepted, and placed on file. The reports of the corresponding secretary, of the recording secretary, and of the treasurer, were read, accepted, and placed on file. Various amendments to the Constitution were proposed and accepted, and copies of the Constitution, as amended, will be mailed to all the members of the Woman's Auxiliary.

Jan 4, 1918

By R. Grierson, R. N. Parkins

The m.echanica1 properties, at high lzomologous temperatures, of the intermetallic compounds InzBi and Mg17A112 were measured as a .function of temperature, applied strain rate, previous thermal and mechanical history, and composition. Mgl,Al12 was investigated ilz compression, whereas Zn,Bi was investigated in tension. A decrease inflow stress with increasing strain was observed jor both alloys. The results obtained are discussed in terms of the dislocation-multiplication processes in these materials. MANY intermetallic compounds are reported to undergo a brittle-ductile transition at high homologous temperatures.' There is evidence in the literature that some of these compounds exhibit a large yield drop when plastically deformed.'j3 Both of these forms of behavior are shown by the covalent elements germanium and silicon4,5 and also by certain ionic compounds.8 The present work is a study of the deformation, at high homologous temperatures (>2/3 Tm), of two intermetallic compounds, In2Bi and Mg17Al12. InzBi has a disordered hexagonal structure7 (c/a = 0.598) and a solubility range of 32.3 — 33.2 at. pct Bi.8 It has a melting range from 72° to 89°C. Mg17Al12 has an ordered bcc (A12 type)7 structure and exists over the range 50 to 60 at. pct Mg8 with a melting range from 437° to 462°C. We have been unable to find any reference to previous investigations of the mechanical properties of BiIn,. Novikovg has reported that cast samples of Mg17A112 show ductility, when bend-tested, at temperatures above 380°C. EXPERIMENTAL Ingots of In2Bi and Mg17Al12 were melted under an argon atmosphere and cast, in situ, in a graphite crucible. The materials used were of 99.99 pct purity. The alloys prepared contained 66.9 at. pct In in the case of In2Bi and 58.4 at. pct Mg in the case of m17A112. The ingots were homogenized and then extruded. Two-in.-diam Mg17Al12 ingots were extruded at 375°C to give 3/8-in.-diam rod. The rate of formation of this rod was 0.25 in. per min. One-in.-diam InzBi ingots were extruded at 20°C, using a rate of 1 in. per min, to give 1/8-in.-diam rod. In both cases the extruded rod had a recrystal- lized, fine-grain, structure. (For Mg17Al12, d = 11.2 µ; for BiIn2, d = 22 µ.) Mechanical-property determinations were made in a hard-beam machine, in tension in the case of In2Bi and in compression with Mgl7Al12. The tensile tests were on specimens having a gage length of 1.1/2 in. and a diameter of 1/8 in. The compression tests on Ml7A112 were on specimens of 3/8 in. diam by 3/8 in. high and the ends were coated with poly-tetrafluorethylene to minimize friction. RESULTS In2Bi. Fig. 1 shows, particularly at the higher applied strain rates, that In2Bi exhibits a marked yield drop as the deformation increases to about 2 pct, after which the material shows neither hardening nor softening up to 15 pct strain. The magnitude of the yield drop, the stress in the region of flow under constant stress (the stress plateau), and the 0.5 pct proof stress were all dependent upon the applied strain rate according to an expression of the form

Jan 1, 1965

By L. W. Pommier, F. B. Brien

The Rheological properties of pulps are non-Newtonian in character and more than one viscosity parameter is necessary to describe their behavior, therefore, the single term 'apparent viscosity' which has been used in the past may be misleading. The study reported in this paper uses a dimensional analysis based on the Ostwald-de Waele shear stress-rate of shear model for non-Newtonian liquids to develop velocity and resistance equations for falling spheres. An electronic monitoring apparatus was assembled for determining the velocity of metallic bodies as they fall through opaque liquids and suspensions. By means of this apparatus the behavior of the viscosity parameters of the Ostwald-de Waele model and the applicability of the proposed equations were examined for a number of non-Newtonian liquids. The validity of the equations for these liquids was confirmed. Preliminary data collected using solid-liquid suspensions established the validity of the form of the basic equations for these systems. The differential movement of solid particles through solid-liquid pulps and suspensions is very important LO many branches of engineering, such as minerals processing, soil mechanics, ceramic slip processing, oil well drilling-mud technology, materials-handling in pipelines, and many others. There is a dearth of fundamental knowledge on the flow resistance encountered by immersed bodies moving through solid-liquid suspensions. The resistance offered by Newtonian liquids to the movement of free settling spheres is well described for laminar and turbulent conditions by Stokes' and Newton's Laws, respectively. However, problems are encountered when attempts are made to extrapolate these simple relationships into solid liquid suspensions. The rheological properties of pulps are such that they are non-Newtonian in character;'" that is, the applied shearing stress and resulting rate-of-shear are related by non-linear functions, and thus, in the simplest case two viscosity parameters are necessary to describe their rheological properties. For this reason the single term 'apparent viscosity' which has been commonly used to explain the flow resistance of suspensions and non-Newtonian liquids may be misleading. It is realized that a rigorous analysis of the rnechanisms of momentum transport of liquid-solid systems is complex indeed. There are many variables that affect the rheological properties of the systems such as density, size, shape, and surface energy of the suspended solid and density and viscosity of suspending liquid, as well as the solid to liquid ratio. However, it was felt that a useful contribution to the knowledge of the behavior of suspensions could be made by examining the systems in terms of the basic fundamentals of nowNewtonian flow. This has led to the development, by means of dimensional analysis, of velocity and resistance equations, using two viscosity parameters to describe the velocity of penetrating bodies and the flow resistance encountered by these bodies, as they pass through non-Newtonian systems. THEORY In order to examine the effects of the rheological properties of solid-liquid suspensions on the movement of immersed bodies it is appropriate to start with non-Newtonian liquids and develop equations, analogous to those of Stokes and Newton, for laminar and turbulent flow respectively, from which quantitative information may be obtained. Further investigation would then be directed at the complex suspension systems, and the effects of the many variables on the velocity and resistance equations. Liquids are classified on a basis of viscosity which may be defined as the relationship between applied shear stress and resulting rate of shear?-'* Pure single phase liquids composed of small light molecules behave as Newtonian liquids, having a single viscosity parameter since the shearing stress and rate-of-shear are related by a linear function. Bingham plastics are similar but have a yield stress. Of particular importance in our investigation are dilatant (shear thickening) and pseudoplastic (shear thinning) non-Newtonian liquids, with and without yield values.

Jan 1, 1968

By Franz Posepny

CONTENTS. Introduction. Part I. General Facts And Theories. [ ]

Jan 1, 1902