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By Carl F. Floe, John Chipman

THE system molten copper-oxygen-sulphur is of interest from both the practical and theoretical standpoints; practically, because oxygen and sulphur play an important role in the commercial production of copper, and theoretically because it offers a chance to study the reaction between an oxide gas, SO2, and a molten metal. Reactions of this type, such as that between CO or C02 and molten iron, are important in many metallurgical operations. Again, the determination of any gas-metal equilibrium is of theoretical interest and value insofar as it contributes to the general development of the laws for solution of gases in metals. This problem is being given an increasing amount of attention in modem metallurgy. This paper is the first of a series and presents the results of a determination of the solubility of sulphur dioxide in molten copper at temperatures from 1100° to 1500°C., and pressures from about 20 mm. of mercury to somewhat above atmospheric. REVIEW OF PREVIOUS WORK The solubility of gases in most liquids has been found to obey Henry's law, which states that for a fixed temperature the amount of gas dissolved is directly proportional to the pressure. However this law does not hold for liquid metals. Instead, it appears that for many gases, particularly the simple diatomic ones such as 02, N2 and H2, the amount dissolved in liquid metals is directly proportional to the square root of the pressure. This is known as Sieverts' law. It may be recognized as a special case of Henry's law, which applies when the solute gas is dissociated into atoms or when it reacts with the solvent metal to form solute molecules containing single atoms of the gaseous elements, as, for example: [2M -}-G2 = 2MGK =G) IYf X[I]] which, if the solubility is not too high and the concentration of metal therefore nearly constant, can be simplified to: [MG = Ki Pa,[2]] Following the same reasoning, it would be expected that the solubility of SO2 in copper would be proportional to the cube root of the pressure, the reaction being as follows: [6Cu + S02 = Cu2S + 2Cu20[3] K Cu2S X (Cu20)2(Cu)e(Psm)[4]] or, neglecting the change in metal concentration and considering that the concentrations of sulphur and oxygen are both proportional to the volume V of gas absorbed: [K1 =or Vdo,= K2/PBO [5] PsO]

Jan 1, 1941

By C. R. Taylor, John Chipman

THE study of chemical reactions of liquid steel and basic open-hearth slag involves a complex slag system of at least eight important components, and often a number of others. In initiating an experimental program on the equilibrium relationship of slag and metal, it became evident that but little progress could be expected in the interpretation of the complex slags until an understanding had been gained of the simpler liquid systems composed of a limited number of slag constituents. The simplest system that in any way resembles open-hearth slag must contain lime, silica and iron oxide. Attempts to produce in an induction furnace slags containing only these constituents have met with serious limitations because of the solubility of refractories in the slag. Thus in acid-lined furnaces the slag is always saturated with silica and consequently contains between 48 and 63 per cent of this component. In basic-lined furnaces an undesired additional component, magnesia, is introduced to the extent of some 3 to 15 per cent, depending upon the acidity, sometimes with disastrous results to the furnace. Thus in a magnesia-lined furnace, Fetters and Chipman1 found it impossible to prepare slags in which the ratio (CaO + MgO)/SiO2 was less than that corresponding to the metasilicate (approximately 0.8: I). Between this composition and that of the true acid slags lies a field of composition about which very little is known and which cannot be explored by any ordinary means. This circumstance, as well as the desire to study the more basic slags in the absence of magnesia, calls for the development of a method by which slags may be brought into equilibrium with molten metal without coming in contact with refractory. Such a technic has been provided by the rotating induction furnace developed by Barrett, Holbrook and Wood.2 Three modifications of the rotating furnace were described by these authors. The first was essentially a rotating refractory cylinder containing the magnesia crucible, which was itself heated by a graphite crucible. In the second, only the magnesia crucible rotated, the cylindrical graphite heater being stationary. In the third, the coil and crucible revolved, and the metal was heated directly by induction. EXPERIMENTAL METHOD Furnace The furnace used in this investigation differed from previous designs and may be considered a fourth modification of the original rotating furnace. Its essential features are shown in Fig. I. The outer case A is a fire-clay flue liner for control of the atmosphere. The top B and base C are alberene stone. The coil supports D are of "Formica," a material formed from phe-

Jan 1, 1942

By D. C. Buffum, L. D. Jaffee

QUANTITATIVE measurements of the temper brittleness of steel are made by comparing the difference between embrittled and unembrittled specimens in the temperature of transition from ductile to brittle fracture. Since hardness affects the transition temperature, a study of the combined effects of hardness and temper brittleness appeared desirable. In this investigation a commercial SAE 3140 steel, which has been reported on previously in temper brittleness studies,* was used. Blanks from this steel were austenitized for 1 hr at 900°C and water quenched. The blanks were then divided into six groups and further heat treated as follows: Group 1—tempered at 675°C for 4 hr and water quenched; Groups 2, 3, 4, and 5—tempered at 675", 650°, 625', and 600 °C respectively for 1 hr and water quenched; and Group 6—tempered at 500°C for y2 hr and water quenched. Each of these groups was divided into two parts; one part was tested without further heat treatment, and the other was embrittled for 48 hr at 500°C and water quenched. Tempering treatments between 500" and 600°C were avoided because of the rapid embrittlement occurring in that range for this steel. The heat-treated blanks were machined into standard V-notched Charpy bars. Each group was tested over a range of temperatures on a 217 ft-lb Charpy machine. The energies necessary to fracture the bars and the percentage fibrous fracture of each bar were recorded. The transition temperatures were obtained from a plot of the percentage fibrous fracture as a function of testing temperature. They were taken as the lowest point on these curves at which the fracture was 100 pct fibrous. The transition temperatures for both embrittled and unembrittled specimens are presented in Fig. 1 as function of the hardness. It will be noticed in this figure that the point for the unembrittled condition at 21 Rockwell C is out of line. These specimens were tempered for 4 hr at 675 °C and this point indicated that under isothermal conditions at this temperature, as is well known, embrittlement may develop fast enough to more than offset the effects of softening. From this data, it was concluded that the difference between transition temperatures for the embrittled and unembrittled conditions at any given hardness, within the range of Rockwell C 24 % to 32lh, is constant. It is also concluded that, within the hardness range studied, the transition temperatures for embrittled and unembrittled specimens rise in a parallel fashion with an increase in hardness. The authors wish to acknowledge the assistance of Frank Carr in this work.

Jan 1, 1952

By W. McA. Johnson

The work of J. E. Johnson, Jr., on the effect of small amounts of oxygen in cast iron in increasing its strength and resistance to shock, is of interest from the technical and scientific standpoints. The following exposition of the theory carries Mr. Johnson's explanation further and, in my opinion, will disclose certain related phenomena and perhaps shed further light on the subject. Some facts, so novel in character as to excite incredulity, have been accepted finally by many metallurgical authorities. One of these is that oxygen to the amount of 0.060 per cent. in cast iron gives it a breaking strength of 3,500 Ib. per square inch, compared with a breaking strength of 2,500 lb. per square inch in cast iron of the same composition with respect to elements other than oxygen, but having only 0.010 per cent, oxygen. The "oxygenated" cast iron, even if made in a coke furnace, has properties equivalent to the best charcoal pig iron. Mr. Johnson has also established the fact that the variations in combined carbon cannot account for the results. By microphotographic evidence he has shown that in oxygenated cast iron the graphite particles are dense and spherical, while in well-deoxidized cast iron the graphite particles are flaky and leaf-like. It is just a matter of common sense that iron of the latter structure is much weaker than the former. The analytical and microscopical work has been done with care and there is no doubt in my mind about the accuracy of the experimental results. In this paper then, we shall consider it as accepted that small amounts (0.060 per cent.) of oxygen increase the strength of cast iron by producing a structure in which the round and solid particles of graphite are surrounded firmly by a principal matrix of ferrite. The purpose of this paper is to show that the reason why the graphite particles are round is founded on the fact that the particles of any precipitate are made denser and harder by the presence of a reagent having a solvent action on the precipitate. This can be stated as a law, although I have never seen it so given in any textbook. Let us then, for purposes of illustration, give a concrete example and develop the theory of such mechanical and chemical actions as occur: It is well known that, by a soluble sulphate, a barium salt in solution is precipitated in a dense and easily filtered body when the solution is

Jan 1, 1916

By E. J. Rapperport, J. P. Pemsler

We have made calculations to evaluate the sensitivity of atomic absorption as a technique to measure vapor pressure changes with temperature. Our conclusion, supported by the experimental findings presented in this work, is that the ultimate sensitivity of the technique is well below lo-' Torr. This magnitude of vapor pressure sensitivity makes the method extremely attractive for thermodynamic studies. Atomic absorption techniques have been used previously in this connection by Scatchard and Boyd' and by vidale2 with a much lower sensitivity reported. Scatchard and Boyd's work measured cadmium pressure over Ag-Cd alloys in the range 0.02 to 0.3 Torr, and Vidale estimated that sensitivities of only 10"5 to 10"6 Torr are to be expected. Atomic absorption appears to be particularly well-suited to thermodynamic studies for several reasons: A) It is extremely sensitive; our experiments indicate an ability to measure vapor pressure changes of 10"9 Torr. B) It is highly selective; there is seldom interference among the resonant wavelengths of the various species. C) It may be performed in an absorption cell under static conditions. This alleviates such problems as surface impoverishment of alloys, attainment of equilibrium, and temperature measurement and control. D) Simultaneous, or near-simultaneous, vapor pressure measurements may be made for several elements in a given system. Experimental. The physical basis of the technique is the highly selective absorption of particular wavelengths by specific atomic species. In most atomic absorption work the element of interest is incorporated into a hollow cathode lamp to provide a characteristic spectral source of high intensity. The spectra lines characteristic of the element in the cathode are attenuated by atoms of that element in the radiation path. Radiation from silver or cadmium hollow cathode lamps was directed along a path containing a 10-cm evacuated silica cell. The cell was positioned within a silica windowed furnace and contained silver, cadmium, or an Ag-Cd alloy. As the furnace temperature was elevated, the number of atoms of the absorbing element in the vapor phase within the cell rose, and the resonant radiation was increasingly absorbed. Intensities were measured by passing the radiation through a Techtron Model AA-4 one-half meter grating atomic absorption spectrometer equipped with a photo-multiplier detector. In order to minimize instabilities in the source, the hollow cathodes were allowed to warm up for several hours and were run at only 2 5 to 30 pct of their maximum rated amperage. In addition the attenuated beam was monitored before and after each reading. The attenuation of resonant wavelengths may be related to vapor pressure by the following relationships.

Jan 1, 1969

By Edward Saibel

THE object of this study is to investigate the effect of prior tensile strain on the fracture stress of a metal. This is done in a theoretical manner starting from the point of view developed by the author in his thermodynamic theory of the fracture of metals. The results are compared with experimental findings and a rational interpretation is given to work that shows the variation of fracture stress with prior tensile strain. THEORY OF FRACTURE In the thermodynamic theory of the fracture of metals developed earlier,1 it was shown that a critical strain energy per unit volume exists. This is characteristic of the material and may be calculated from basic thermodynamic data. When the area under the flow curve reaches this characteristic value, fracture occurs. The general criterion for fracture is expressed in the form u ± uo = JLm?AV/V [1] where Lm, is the latent heat of melting of the unit volume, ?V/V is the ratio of the change in volume of the unit volume to the original unit volume on passing from the solid to the liquid state, [uo] is an initial energy density, and J is a conversion factor, which changes energy from heat to mechanical units. As a first approximation, it will be assumed that the stress-strain curve is the straight line that extends from the point of maximum load onward, extrapolated back to the axis of zero strain, for example, line AC of Fig. 1. If the point of intersection of the straight line with the axis of zero strain is represented by so, and the slope of the straight line is p, the analytic form of the flow curve is [s = s + pd [2]] and the strain energy per unit volume evaluated from [JvdS] becomes (vsod + pd2/ 2). When this latter term reaches the critical value JLm?V/V (designated hereafter by M), it is assumed that fracture occurs. This leads to the following expression for the fracture stress: [s1 = \/C r.2 + 2Mp [31] The strain at fracture may be calculated from Eqs 2 and 3. It is assumed in this paper that the initial energy density is either zero or that it may be neglected. Furthermore, the complicated states of stress and of strain existing in the necked region of the tensile specimen after "necking" has occurred will also be neglected for the present, so that average conditions will be assumed to prevail. FLOW AND FRACTURE CURVES Ludwig2 attributed to materials two fundamental properties: (I) a resistance to flow and (2) a resistance to fracture. He reasoned that at each instant the

Jan 1, 1947

By John M. Hartman

On May 19th, 1857, an English patent was granted to E. A. Cowper for heating air or other gases under pressure by means of a regenerator inclosed in an air-tight iron case, having between the regenerator and case a lining of brick. This patent provided for heating the stoves by a separate fireplace, or by gas direct from the blast furnace. A number of forms of interior arrangement of the brickwork are shown in the drawings; also hollow poppet valves with hollow stems, and a pipe inside of the stem for circulating the water; the valve seats have coil cast in them for water circulation to keep them cool; slide valves, with snake coil cast in the discs, are shown, and the use of cold air for cooling the valves is also described. The combustion-chamber of these stoves was central, and openings mere provided at the top and bottom to get into the stoves. These Cowper stoves are all circular in section. November loth, 1865, an English patent was granted to Thomas Whitwell for regenerative stoves for heating air or gas, provided with cleaning openings at the top and bottom capable of being closed with firebrick plugs and doors. The drawings show a rectangular stove inclosed in an iron case. The interior brickwork has numerous upand-down passages through the stove, but there is no claim on the interior construction. March 3d, 1868, an English patent was granted to Charles Cochrane for a slide valve to be subjected to high heats. The disc of this valve was hollow, and had a circulation of water through it by the two hollow stems that operated it. The valve-seat was detachable and had a coil cast in it, through which water circulated. The valve and seat were placed on an incline to the body to cause the valve-disc to lie on the valve-seat. A cap was placed on the bottom of the body to get at the interior readily. January 5th, 1870, an English patent was granted to Siemens, Cowper and Cochrane for the construction of regenerators in firebrick stoves, with numerous vertical passages of sufficient size to allow a brush to pass through and clean them. These passages had slight projections on the sides to tarn the air over and over as it passed through. A claim also covered the use of horizontal passages connected at each end alternately, and the use of blasts or jets of air,

Jan 1, 1880

By Joan M. Hartman

ON May 19th, 1857, an English patent was granted to E. A. Cowper for heating air or other gases under pressure by means of a regenerator inclosed in an air-tight iron case, having between the regenerator and case a lining of brick. This patent provided for heating the stoves by a separate fireplace, or by gas direct from the blast furnace. A number of forms of interior arrangement of the brickwork are shown in the drawings; also hollow poppet valves with hollow stems, and a pipe inside of the stem for circulating the water; the valve seats have coil cast in them for water circulation to keep them cool; slide valves, with snake coil cast in the discs, are shown, and the use of cold air for cooling the valves is also described. The combustion-chamber of these stoves was central, and openings were provided at the top and bottom to get into the stoves. These Cowper stoves are all circular in section. November 10th, 1865, an English patent was granted to Thomas Whitwell for regenerative stoves for heating air or gas, provided with cleaning openings at the top and bottom capable of being closed with firebrick plugs and doors. The drawings show a rectangular stove inclosed in an iron case. The interior brickwork has numerous up-and-down passages through the stove, but there is no claim on the interior construction. March 3d, 1868, an English patent was granted to Charles Cochrane for a slide valve to be subjected to high heats. The disc of this valve was hollow, and had a circulation of water through it by the two hollow steins that operated it. The valve-seat was detachable and had a coil cast in it, through which water circulated. The valve and seat were placed on an incline to the body to cause the valve-disc to lie on the valve-seat. A cap was placed on the bottom of the body to get at the interior readily. January 5th, 1870, an English patent was granted to Siemens, Cowper and Cochrane for the construction of regenerators in fire-brick stoves, with numerous vertical passages of sufficient size to allow a brush to pass through and clean them. These passages had slight projections on the sides to turn the air over and over as it passed through. A claim also covered the use of horizontal passages connected at each end alternately, and the use of blasts or jets of air,

Jan 1, 1880

By Brison Robertson, W. P. Fishel

The carbide-forming tendencies of the various steel-alloying elements, or their affinities for carbon, is a subject that has received considerable attention, but little more than a probable arrangement of the elements as to their carbide-forming tendencies has been proposed. The physical properties of alloy steels depend upon the relative proportions of the elements present and their combinations. one important phase of this subject is the distribution of carbon between the various elements present. The distribution of car. bon between iron and other elements evidently sill depend upon: (I) the affinity of each for carbon; (2) the relative atomic masses of the elements present; and (3) the possible formation of compounds between the alloying and iron and between the elements themselves, In ternary steels the case is simplified, especially in systems in which the element and iron form no compounds, In such systems iron and the alloying element are competing for the carbon present. In this work the distribution of carbon between titanium and iron has been studied by measuring the relative amounts of iron carbide and titanium carbide present ill a series of annealed steels in which the ratio of titanium to carbon extended from 0.527 to 4.61. Ten Fe-Ti-C alloys, weighing about 250 grams each, were prepared by melting under a Vacuum, in an Induction furnace, Armco iron, carbon-free ferrotitanium (25 per cent Ti), and pure carbon. Vacuum melting prevented the formation of titanium oxides and nitrides, which would the the problem. The melts were made in graphite crucibles lined with sintered magnesium oxide. The ingots were the in the furnace under a vacuum and "'ere then completely annealed at 950°C. The determination of the amount of titanium carbide present was based upon the established insolubility of titanium carbide in boiling dilute (1:4) sulphuric acid, and the complete solubility Of free titanium and titanium-iron compounds in this acid. High-carbon ferrotitanium, which had been treated to remove free Ti and Fe. was found to be completely insoluble in the acid; and the carbon-free ferrotitanium used in making the alloys was found to be completely soluble. Others have reported the insolubility of titanium carbide in sulphuric and hydrochloric acids. Turnings from the ingots were digested with boiling sulphuric acid (1:4) until all action had ceased. The carbide residue was filtered off and analyzed for titanium, and in some cases for carbon. This represerifs the titanium that was united with carbon The filtrate from the carbide residue contains the portion Of the titanium that was in solid solution in the ferrite. Titanium

Jan 1, 1945

By Emby Kaye

IT is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and. Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the function of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. SOME ECONOMIC FACTORS The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves. in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercompressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreciate the variables in sampling gas from

Jan 1, 1941

By Lawson P. Entwistle

One of the important reserves of mangani-ferous iron ore is at Boston Hill, near Silver City, New Mexico. The area consists of a faulted block of gently dipping Lower Paleozoic shale, dolomite, limestone and sandstone, which has been intruded by a roughly circular mass of quartz-bearing monzonite porphyry and subordinate dikes. Prom a noselike protuherance of the intrusion radiate many premineral faults, which have localized much of the hypogene mineralization. Three important stages of hypogene mineralization can be recognized: (I) mesitite, a manganiferous iron magnesite, (2) quartz sulphides, and (3) barite-galena The carbonate stage is widespread but stronger near the intrusion. The quartz may have been derived from hydrothermal alteration of the igneous rocks. Barite-galena is most important in the Chloride Flat mining district, about one mile north, where argentiferous galena provided silver for the supergene ore. The hypogene carbonate, lean in iron and manganese, has been oxidized and consequently enriched by meteoric waters containing an excess of oxygen and carbon dioxide to form ore bodies of intimately mixed hematite and pyrolusite. The ore bodies, at one place attaining a length of 1600 ft., a width of 300 ft., and a thickness of 25 ft., are largely confined to areas of brecciation and to spreads from faults in Silurian dolomite beneath soft Devonian shale. Boston Hill comprises three rolling hills southwest of and adjoining the town of Silver City (pop. 5044), Grant County, N. Mex. The mining district covers less than 2 sq. miles. Silver City, on a branch line of the Atchison, Topeka, and Santa Fe Railway, is a supply point for the important mining communities at Santa Rita, Hurley, Hanover, Tyrone, and Mogollon. The Chloride Flat mining district adjoins Boston Hill on the north. History and Production Bonanza-type silver ores were discovered in the Chloride Flat mining district during the silver boom of the seventies and eighties, at which period it has been credited with as much as $5,000,000 production. In 1916 manganiferous iron ore was first shipped from the Boston Hill mining district to Pueblo, Colo., where it was mixed with manganese ore from Lead-ville and smelted into spiegeleisen. During 1926 and 1927 the Colorado Fuel and Iron Co. mined and churn-drilled part of the district. Mining operations ceased during the depression of the thirties, but production was resumed in 1937. Since 1916 the Boston Hill mining district has produced about 600,000 long tons of ore averaging about 12 per cent manganese and 35 to 40 per cent iron.

Jan 1, 1949

By Lawson P. Entwistle

One of the important reserves of mangani-ferous iron ore is at Boston Hill, near Silver City, New Mexico. The area consists of a faulted block of gently dipping Lower Paleozoic shale, dolomite, limestone and sandstone, which has been intruded by a roughly circular mass of quartz-bearing monzonite porphyry and subordinate dikes. Prom a noselike protuherance of the intrusion radiate many premineral faults, which have localized much of the hypogene mineralization. Three important stages of hypogene mineralization can be recognized: (I) mesitite, a manganiferous iron magnesite, (2) quartz sulphides, and (3) barite-galena The carbonate stage is widespread but stronger near the intrusion. The quartz may have been derived from hydrothermal alteration of the igneous rocks. Barite-galena is most important in the Chloride Flat mining district, about one mile north, where argentiferous galena provided silver for the supergene ore. The hypogene carbonate, lean in iron and manganese, has been oxidized and consequently enriched by meteoric waters containing an excess of oxygen and carbon dioxide to form ore bodies of intimately mixed hematite and pyrolusite. The ore bodies, at one place attaining a length of 1600 ft., a width of 300 ft., and a thickness of 25 ft., are largely confined to areas of brecciation and to spreads from faults in Silurian dolomite beneath soft Devonian shale. Boston Hill comprises three rolling hills southwest of and adjoining the town of Silver City (pop. 5044), Grant County, N. Mex. The mining district covers less than 2 sq. miles. Silver City, on a branch line of the Atchison, Topeka, and Santa Fe Railway, is a supply point for the important mining communities at Santa Rita, Hurley, Hanover, Tyrone, and Mogollon. The Chloride Flat mining district adjoins Boston Hill on the north. History and Production Bonanza-type silver ores were discovered in the Chloride Flat mining district during the silver boom of the seventies and eighties, at which period it has been credited with as much as $5,000,000 production. In 1916 manganiferous iron ore was first shipped from the Boston Hill mining district to Pueblo, Colo., where it was mixed with manganese ore from Lead-ville and smelted into spiegeleisen. During 1926 and 1927 the Colorado Fuel and Iron Co. mined and churn-drilled part of the district. Mining operations ceased during the depression of the thirties, but production was resumed in 1937. Since 1916 the Boston Hill mining district has produced about 600,000 long tons of ore averaging about 12 per cent manganese and 35 to 40 per cent iron.

Jan 1, 1949

By Colin Fink

THE important developments within the past few years in electrochemistry, in particular in the electric furnace art, in electrometallurgy and in the methods of combatting corrosion are to be the subjects of my discussion. Fig.1 shows the rise of the electric steel furnace industry in this country and Canada. Many prophesied that the electric furnace was largely a war baby and that the sudden rise in the industry, due to the outbreak of the great war, would be fol-lowed by an equally sudden drop after the armistice. However, the curve shows that this, prophecy was not correct; the number of furnaces in operation in this country and Canada has continued to increase steadily, so that at the end of 1925 there were over 525 electric steel furnaces in successful operation. What does this mean? It has a big significance, namely that the en-tire steel industry has been revolutionized, to a certain extent, that we have been able to introduce certain alloys and steel products that we were unable to pro-duce before. On the table is. a sample of metallic chro-mium, analyzing more than 98 per cent chromium, made in the electric furnace. Before the war, the only commercial method of producing chromium was that by the Goldschmidt process. If chromium oxide is mixed with granulated aluminum, a violent reaction occurs, resulting in the production of metallic chro-mium. However, the price of chromium so made will always be above that of the raw material, which at the present time is about 27 cents a pound.. Furthermore, the chromium metal could only be turned out in small quantities, whereas in the electric furnace, large quan-tities, ton masses, can be produced today. The advent of chromium produced in the electric furnace has brought about an entire new phase in the alloy indus-try. The fuel-fired furnaces can turn out a low-carbon chromium steel that runs about 3 per cent chromium, whereas in the electric furnace, 60 per cent ferro-chromium is daily produced in large masses with almost entire elimination of carbon. It is difficult indeed to turn out ferrochrome very low in carbon. New steels are being produced today, for example the steel with which everyone has become familiar within the 'last few years, "stainless steel,". and which would have been impossible without the low-carbon ferrochrome. The elimination of most of the carbon made it possible to roll the chromium steels into thin sheets and manu-facture them into knife blades.

Jan 2, 1927

By W. McA. Johnson

The object of this paper is to describe the several necessary characteristics of the zinc-retorting charge and to show how by certain improved methods, the large excess of coal, over that theoretically required, can be reduced, thereby effecting an increase in the smelting capacity of a retort plant as well as other economies. In the southwestern zinc works a charge of roasted zinc ore with a side mixture of carbonates and silicates, analyzing on the average 50 per cent. Zn, is mixed with 55 or more per cent. of its weight of a mixture of coal and coke analyzing 60 to 70 per cent. fixed carbon. The ore is of varying fineness and the coal and coke are usually crushed in a semi-moist condition through a 3/8-in. screen. With ores of a slaggy nature, this coal proportion is increased, sometimes to as much as 100 per cent. of the weight of the ore. With carbonate ores, or where anthracite screenings with higher carbon content are cheap enough, the percentage of reducing agent is cut to 45 per cent. or even somewhat lower. The average charge per retort for a monthly run of a plant on ore, as distinguished from retorts on blue-powder, ladle-skimmings and other between-products, runs from 60 to 66 lb., with a mean of 63 lb. for the Southwest with standard retorts of 8 1/2-in. inside diameter and 50 in. long inside, using roasted sulphide ores. Conditions will change these figures, but 40 lb. of ore per cubic foot of retort space is, I believe,'an average in the better-operated plants. Since the rise in the price of spelter, the tendency has been to overcharge. To remove the slag that is formed when retorts are overcharged, extra men are put on to "gum-chisel" the retorts to prevent "set" furnaces and "butchered retorts." Taking the above conditions as premises, we find that from four to six times the amount of coal necessary for the reduction is used, as is evidenced by the fact that the residues analype as high as 35 per cent, fixed carbon. There are good reasons why this excess of fixed carbon must be used and perhaps these can be best explained by a description of the metallurgical requisites of a zinc charge. We may enumerate these as follows: 1. High reducing power, especially at the end of the shift, to reduce any carbon dioxide to monoxide and bring about a good condensation

Jan 1, 1918

By Howard Eavenson

ONE who has been trained in belief in the law of supply and demand and its effect upon prices finds it difficult to adjust himself to the minute regulations imposed by the New Deal, and also to the bewildering changes of government policy as expressed within a short period of time between the antitrust laws and the N.R.A., and later by the Bituminous Coal Conservation Act of 1935. A survey of the coal industry since the World War, both in this country and Great Britain, however, shows that regula-tion of some sort is needed if any stabilization is to be achieved and if the Wage structure and economic welfare of the many communities dependent solely upon coal are to be maintained. Let us look at what has happened to the industry since 1920, which can be considered as the end of the period affected by the war influence. This discussion will be confined solely to bituminous coal, although many of the general conditions are equally applicable to anthracite, the position of which now is at least as bad as that of the softer variety. Since 1920-to the end of 1934-the production of coal has decreased from 568.7 million to 358.4 million tons, or 37 per cent; the number of mines from 14,766 to 6,258, or 58 per cent; the average annual production per mine has changed from 38,512 to 57,425 tons, or 50 per cent. The number of large mines has increased considerably, and the number of men employed has decreased from 639,547 to 458,011, a reduction of 28 per cent, while the average output per employee has changed from 4.0 to 4.4 tons, or an increase of 10 per cent. The average price per ton of coal at the mine has varied from $3.75 to $1.75. During that time wages decreased largely until 1933 and since that time have increased, until now the rates paid are- considerably above those in other occupations, although the actual yearly earnings are low, because of part-time work. From 1920 to the signing of the Jacksonville wage agreement in 1924, about two-thirds of the men were union members and practically all of the nonunion mines were south of the Ohio River; with the fixing., of the high wage scale of that agreement, which soon proved to be an uneco-nomic one, many of the mines found that they could not retain their business, so gradually changed to nonunion. By 1928 the proportion

Jan 1, 1936

By R. J. Miller, W. A. Bates

ALTHOUGH cresylic acids have been standard frothers in flotation for many years, there has been little discussion of their nature in the metallurgical literature. Aside from references in the patent literature, the paper by Landolt, Hill, and Lowy1 in 1930, which presented a study of the frothing and collecting properties of some of the constituents of crude cresylic acids, represents the only contribution of this type. The close froth control required in the delicate selective separations of present-day flotation operations have required the flotation metallurgist to choose his frothers with care, and have caused him to require of the manufacturer a closely controlled, uniform product. A background of knowledge of the chemical composition and physical and chemical properties of the frothers, by which their action may be correlated, should aid in selecting frothers for particular flotation requirements. Further, the recent almost complete replacement in flotation of coal-tar cresylic acids by those derived from petroleum makes it especially desirable to review the flotation behavior of the acids from the old and the new sources. In view of these facts the Milling Methods Committee of the A.I.M.E. suggested to the Oronite Chemical Co. of San Francisco the preparation of a paper on the subject, and this paper has accordingly been prepared as a contribution by the California Research Corporation, the research affiliate of the Oronite Chemical Co. The discussion is from the following aspects: (I) constitution and properties; (2) sources; (3) comparison of coal-tar and petroleum cresylic acids ; (4) characteristics as frothers, with particular reference to the effect of the substitution of petroleum acids for coal-tar acids. CONSTITUTION AND PROPERTIES Cresylic acids are commonly regarded as mixtures of orthocresol, metacresol and paracresol. This was, indeed, the former meaning of the term, but in recent years it has been loosely applied to any mixture of alkyl phenols boiling above 190°C.; that is, excluding only phenol itself. This means that cresylic acids, as they are known today, may consist of mixtures, not only of the three isomeric cresols, but of six xylenols and of a variety of higher boiling homologues. Generically the constituents of cresylic acids are alkyl phenols, and they are often so designated in the literature to avoid the more indefinite term, "cresylic acids." They form an homologous series starting with phenol, which has the familiar benzene ring, with an hydroxyl group in place of one of the hydrogen atoms. The series of alkyl phenols is formed by the substitution of alkyl side chains, such as methyl, ethyl, propyl, butyl, etc., for hydrogen

Jan 1, 1946

By B. J. Harlan

The trying times experienced by the steel industry during the past four years have emphasized the necessity of producing pig iron at the lowest possible cost. The trend in both design and operation of blast furnaces has been toward this end rather than toward securing maximum production from a unit or group of units. In the following discussion the trend in design of stacks and auxiliary equipment will be taken up before operation is considered. Although few furnaces have been constructed in the past few years, the trend is definitely toward larger furnaces with a hearth diameter of 24 or 25 ft. Such a furnace is very flexible, being able to produce efficiently any desired daily tonnage between 500 and-1000 or more. The detail of the design of furnace stacks, with the exception of the top, has changed little in recent years. To decrease the velocity of gas through the throat of the furnaces, thereby reducing flue-dust losses, the stock-line areas are constantly being made larger. The top dimensions of the larger furnaces are usually as follows: Stock-line diameter, 19 to 20 ft.; large bell diameter, 14 to 15 ft.; straight section of throat, 5 to 10 ft. high; inwall batter, 1 to 11/4 in. Pe ft. The ratio between the area of the stock line and the area of the large. bell is usually about 1.85 to 1. The stock-line diameter of some smaller furnaces has been increased to that of the hearth diameter of the stack at the expense of the stack batter. Remarkable decreases in flue-dust production are claimed for the so-called " Venturi top," which is achieved by flaring the stock line, in the form of an inverted cone, from a diameter of 17 ft. at 10 ft. below the large bell closed to a diameter of 19 ft. 6 in. at 3 ft. below the large bell closed. Time alone will tell which of the two designs is the better. Because of differences in raw materials, one top may be better for some plants and the other top for other plants. In the search for lower costs and higher efficiencies all operators are, adopting stoves that will maintain maximum hot-blast temperatures with a minimum gas consumption. To meet these requirements, stove capacity of approximately 7 sq. ft. of heating surface and 1.8 cu. ft. of brick volume is required per cubic foot of wind blown per minute.

Jan 1, 1934

By T. Koulomzine

The theory of the Askania mag-netometer, as well as a complete discussion of all factors influencing magnetometer readings, is very ably described by J. Wallace Joyce.1 We will assume that the reader is thoroughly familiar with this theory and we will use whenever possible the same notations for the physical values involved in the theory. On the other hand, we believe that the principal formulas of the magnetometer can be deduced much more easily by the use of differential calculus than by the methods employed by Joyce. Consequently, we are presenting herewith a resumé of the theory of the vertical magnetometer in order to determine the correct formula of the temperature coefficient which we propose to compensate. Short Theory of the Vertical Magnetometers We shall accept the following notations: m = total mass of the magnet system, in grams. g = acceleration of gravity, in dynes. a = projection on the axis of the magnet system of the distance between the axis of support and the center of gravity of the magnet system, in centimeters. h = projection on the perpendicular to the axis of the magnet system of the distance between the axis of support and the center of gravity of the magnet system, in centimeters. M = 2pL = M, magnetic moment of the magnet system. Z = vertical component of the earth's magnetic field. ? = deflection angle of the magnet system. = focal length of objective lens in the optical system S = scale reading. In a vertical magnetometer the axis of the magnet system is kept horizontal within 2". Therefore, referring to Fig 1, we see that the magnetic torque of the magnet system influenced by Z must be counterbalanced by the gravity torque. MZ cos ? = mga cos ? + mgh sin ? or dividing by cos ? MZ = mga + mgh tan ? If we now move to another magnetic station and the temperature conditions change, the values of all the variables will change also: M, a, and h under the influence of temperature. 2, both with time and space. ? and S, as a result of all the above changes. Taking increments in Eq 2 we obtain: (Mo + ?M)(Z + ?Z) = mgao + mg?a + mg(h + ?h) tan (? +??) but tan (? +??), because ? is small, can be replaced by tan ? + tan ??; in fact tan (?+ ??) = sin ?.cos ?? + cos ?.sin ??/ cos ?.cos ?? — sin ?sin ?? but sin ? sin ???0 tan (8 + ??) ? tan ? + tan ??. Fur-thermore, neglecting all terms of the equation containing two differentials becomes: or a differential and a tan ??, Eq 3

Jan 1, 1950

ROBERT PEELE, New York, N. Y. (written discussion *).-This excellent paper is one of a number of recent detailed descriptions of the, methods and plant in use at prominent mines of the country. The publication of such papers cannot be too highly praised. In the past, the interchange of inside information has often been hampered by the disinclination of some mining companies to permit publication of details of their work. These companies apparently have not realized fully that free discussion is of mutual benefit; that members of mine staffs are aided in. keeping up to date, in improving old methods and devising new ones to meet changes in conditions, and, by a wholesome feeling of rivalry, are stimulated to introduce economies and do better work. In writing this paper, Messrs. Haight and Tillson have packed a large amount of information into a relatively small space, and the numerous illustrations, chiefly reductions of working drawings, are valuable. The authors are also to be commended for their highly detailed Table of Contents, which adds to the usefulness of the, subject matter. The method of mining at Franklin does not fall readily into any of the accepted classifications. It is a combination of shrinkage stoping and mining of the pillars by a modified top-slicing method. Attention may be called to the fact that, in the wider parts of the orebody, the stopes, 17 to 18 ft. (5.2 to 5.5 m.) wide are transverse; in the narrower parts, they are longitudinal, that is, in the direction of the' strike. This varia-tion is made necessary by the shape and character of the deposit, and distinguishes practice at Franklin from that in some of the western mines. The direction of the stops is changed from transverse to longitudinal when the orebody narrows sufficiently to make the length of a transverse stope approximately equal to its width. Some of the longitudinal stopes exceed 120 ft. (36 m.) in length, and when the hanging wall is bad, requiring prompt filling, three operations' proceed simul-taneously in the same stope, viz., ore is broken at one end, while drawing down goes on in the middle, and filling at the other end. Each transverse stope or chamber is begun by a crosscut from foot to hanging wall, which is afterward enlarged to the stone width and to a height of 12 or 15 ft. (3.7 or 4.6 m.). This preliminary work is done only once for each stope, because the stope is carried up far enough to continue stoping

Jan 1, 1918

By Gilbert H. Cady

Extensive sampling of coal in Illinois during the past 10 or 12 yegrs by the State Geological Survey, in cooperation with various organizations, such as the U. S. Bureau of Mines, the University of Illinois, and the Illinois Cooperative Mining Investigations, has made possible the delineation of two areas of low-sulfur coal in the southern part of Illinois. The $fur content is less than 1.25 per cent., so that, if otherwise suitable, these coals can be employed for metallurgical uses and for the manufacture of water-gas and retort gas. One of these areas is small and lies in Jackson County, near Murphysboro, the other is much larger and includes a large part of the famous Franklin County field. A small area of No. 2, or Murphysboro, coal has been worked for many years near the town of Murphysboro, Jackson County, Ill. In two mines, at least, the coal has a sulfur content of less than 1.25 per cent. It is doubtful, however, whether this field will ever be a source of large tonnage as the total area underlain by low-sulfur coal in workable thickness is probably less than 15 sq. mi. (24.14 sq. km.), and a large part of it has already been worked out.. The location of the area of low-sulfur coal in the Franklin County field is shown in the accompanying map. The small area underlain by the Murphysboro low-sulfur coal is shown near the town of that name in the central part of Jackson County. The larger area lies in the west side of Franklin County, extending also about 6 mi. (9.65 km.) south into Williamson County, about 4 mi. (6.43 km.) west into northern Jackson and western Perry County, and northward an undetermined distance into Jefferson County. All but the northern limit of the area is fairly well defined by sampling in numerous mines. The inner cross-lined area is underlain by coal having less than 1 per cent. sulfur, the outer boundary surrounding the area underlain by coal having less than 1.25 per cent. sulfur. The coal mined in the district is No. 6 or Herrin coal, commonly known as the Carterville or Franklin County coal. The bed has a thickness varying from about 8 ft. (2.4 m.) on the border of the low-sulfur area up to more than 10 ft. (3 m.) in the central portion, locally having a thick-

Jan 1, 1920