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By Charles H. Moore

When lime and magnesia are used as fluxes in the smelting of titaniferous ores fluid, digestible slags low in iron oxide and high in titanium dioxide are produced. The mineral phases present in such slags are (Fe,Mg)O.2TiO2, CaTiO3, and minor amounts of silicate glass (or its devitrification products). The flux additions are added to the ore in relative amounts to crystallize a ratio of (Fe,Mg)O.2TiO2 to CaTiO2, of near the eutectic proportions of 60 pct (Fe,Mg)0.2TiO2 and 40 pct CaTiO3. FeO-Ti02 (ilmenite) remains present in the slag until the FeO content is reduced to approximately 8 pct. Op- timum slag composition is obtained by reducing the FeO content to between 2 and 6 pct. Continued reduction shifts he (Fe,Mg) 0.2Ti02 to oxygen deficient structures classified as MgTi30e and MgTi204. Further reduction yields titanium oxycarbides and freezes the melts.

Jan 1, 1949

By Benjamin S. Lindsey, James Norman

BARITE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to 100 per cent through 325 mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, 11.11 per cent Si02, and 2.85 per cent R203. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder ,was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.' The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of nonmetallic minerals in the presence of a large amount of slime is usually very difficult, and when done is an innovation calling for conditions different from those under which granular material is separated. LABORATORY FLOTATION WORK Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1941

By James Norman, Benjamin S. Lindsey

BaritE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the 'more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to 100 per cent through 325 mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, II.II per cent SiO², and 2.85 per cent R²O3. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.' The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of non-metallic minerals in the presence of a large amount of slime is usually very difficult, and when done is an innovation calling for conditions different from those under which granular material is scparated. Laboratory Flotation Work Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1942

By Benjamin S. Lindsey, James Norman

BaritE (BaSO4) is the most important industrial barium mineral from the standpoint of quantity consumed. In 1938 the amount was 365,000 tons. Its uses are numerous, some of the 'more important being in the production of pigments, as an inert filler in a wide variety of products, as a weighting material in oil-well drilling muds, in the manufacture of some kinds of glass, and in the production of barium chemicals. The barite studied in this investigation occurs as the massive variety in a shale replacement formation near Magnet Cove, Ark. It is intimately mixed with quartz and small amounts of iron oxide and residual shale. Complete liberation of barite and quartz is not obtained when the rock is ground to 100 per cent through 325 mesh. The crude rock with which all test work was done assayed 85.1 per cent BaSO4, II.II per cent SiO², and 2.85 per cent R²O3. Its specific gravity was 4.03. It was found in the course of the investigation that the barite contained a small amount of uniformly distributed carbonaceous material, so intimately dispersed that it could not be seen with the microscope, but gave a definite gray cast to the barite concentrates. The color of the barite in polished sections of the crude rock ranged from gray to almost black, while finely ground powder was a reddish gray. The reddish hue was due to the iron oxide present. In 1939, under the supervision of Oliver C. Ralston,* the Bureau of Mines, in cooperation with the Milwhite Company, of Houston, Texas, undertook to study the flotation of barite from Magnet Cove, Ark. Flotation of several southern barite ores had already been investigated by the Bureau of Mines.' The Magnet Cove barite was unique, however, in that it had to be ground to such an extremely small particle size for liberation. The flotation of non-metallic minerals in the presence of a large amount of slime is usually very difficult, and when done is an innovation calling for conditions different from those under which granular material is scparated. Laboratory Flotation Work Preliminary investigation showed that the flotation reagents recommended by O'Meara and Coe1 for separating barite and siliceous material were suitable, but much larger quantities of reagents were required to separate such finely divided material. Moreover, it was found that careful control of the frothing was necessary. When oleic acid and sodium silicate were used a voluminous froth was observed at the beginning of a test, and toward the end there was not enough froth to effect complete recovery of barite. The addition of pine oil as a frother gave proper frothing for the duration of the test, and the substitution of coconut fatty acid (crude lauric acid) for oleic acid produced a more heavily burdened froth. Two different paper-mill fatty-acid products were tested

Jan 1, 1942

By John J. Theiler

Early in 1963, the Inspiration Consolidated Copper Co., at Inspiration, Ariz., began a program to make automatic the lubrication of several critical points on their KW Dart 37SL haulage trucks. Prior to installation of the automatic lubrication system, all the haulage trucks were serviced by hand every three shifts. Now, with automatic lubrication, the service period has been extended to four shifts. What are the principal benefits to be expected from such a system? 1) Uninterrupted production; 2) extended machinery life; 3) good housekeeping; 4) lower maintenance costs. Of these points, the most important to truck maintenance are extended component life and lower maintenance costs.

Jan 5, 1965

By J. B. Mackintosh

The general method which has been followed since the time of Heinrich Rose, and perhaps before, for the determination of phosphorus in iron and steel, is to dissolve the sample either in nitric acid, aqua regia, or some other oxidizing agent, in order to convert the phosphorus into phosphoric acid. In 1832 Rose* recommends HNO3, or aqua regia, preferably the former. Wohler, in 1854,† directs that the iron should be oxidized by burning in a stream of oxygen for the determination of carbon, and the resulting oxide of iron containing all the phosphorus as phosphoric acid be treated as an ore. In the fourth English edition of Fresenius' Quantitative Analysis,† pp. 666-667, we find directions to dissolve the iron in aqua regia or bromine; and, coming down to more recent times, we find F. A. Cairns § directing the employment of a boiling solution of potassium chlorate and hydrochloric acid for the oxidation and solution of the sample to be analyzed. It is unnecessary to multiply quotations from the literature of the subject, though they might be extended almost inclefinitely, since it would only be a repetition of the above mentioned series of methods in one form or another; and the references given have been selected to show how little essential variation there is in the type-methods of solution used. In fact it seems to be universally accepted as a necessary first step in the determination that some such method of solution should be followed. One chemist, however, struck out on a different line of thought, and to the Lest of my knowledge only one, M. V. Tantin, who, in

Jan 1, 1886

By W. H. Bassett

W H. BASSETT was elected first vice-president at . the executive session of the new Board on Tues- day afternoon. Karl Eilers, H. Foster Bain, Thomas T. Read, and H. A. Maloney were respectively re-elected as treasurer, secretary, assistant secretary and assistant treasurer. The new Executive Committee will consist of W. H. Bassett, Chairman, and Richard Peters, Jr., H. C. Bellinger, E. De Golyer, Edgar Rickard. The Finance Committee will be J. V. W. Reynders, Chair- man, Henry Krumb and H. G. Moulton. George D. Barron was reappointed Chairman of the Admissions Committee, and F. Julius Fohs put in charge of the Papers and Publications Committee.

Jan 1, 1929

By A. Andreas

New Mexico established an annual record by producing 38,897,741 bbl. of oil during 1940. This was approximately 6 per cent greater than the 1939 production of 36,746,840 bbl. The daily average produc-tion was 106,569 bbl. New Mexico retained its position as the seventh oil-producing state. The recommendations of the United States Bureau of Mines were followed by the Oil Conservation Commission in setting the monthly state allowable. At the beginning of the year the average top allowable for each qc-acre unit was 40 bbl. and at the close of the year it was 36 bbl. Remedial work by the operators has been extremely beneficial and satisfactory in reducing the gas-oil ratios in various fields. Gas formerly blown into the air is now being processed by numerous casinghead plants. The Oil Conservation Commission, with the full cooperation of the Proration Office and operators, has taken bottom-hole pressure surveys and has done considerable remedial work in various fields. Two new oil fields and one gas field were discovered in New Mexico during 1940. Numerous extensions to the existing fields were made. Some of these were definitely wildcats in the same townships designated as fields and some, although called extensions, were more than 3 miles from production. Lea County continued to be the largest oil-producing county in the state, with a production of 33,976,394 bbl. It had the largest number of completions during 1940, with 303 oil wells, 9 gas wells and 13 dry holes—a total of 325 wells. Eddy County was the next most active county, with 239 completions, of which 163 were oil wells, 8 gas wells and 68 dry holes. It produced 4,405,158 bbl. of oil during the year. The increased activity in Eddy County and the completion of a large number of producing oil wells have created a transportation problem that can be solved only by additional pipe-line facilities. During the year Eddy County was unable to produce 1,500,000 bbl. of its allowable oil, because there was no pipe-line outlet. There were 601 wells completed in New Mexico in 1940, of which 478 were oil wells, 22 gas wells and IOI dry holes. This was a decline of approximately 9.5 per cent in the number of completions compared with 1939, when 659 wells were drilled. Southeastern New Mexico Lea County.—The largest producing field in Lea County was the Monument field, with 6,894,475 bbl.; followed by Eunice with 6,559,348 bbl. and Vacuum with 4,743,065 bbl. The Hobbs pool, which for years was the largest producing field in the state of New Mexico, was fourth with 3,790,477 bbl. The Vacuum pool was the most active area, having 68 completions, of which 67 were oil wells and one was a dry hole. Only one new field was discovered in Lea County during 1940; the discovery well was in the Caprock area, the Livermore State No. I, in the SE. 1/4 SE. 1/4 sec. 30, T. 12 S, R. 32 E. This well was drilled to a

Jan 1, 1941

By A. Andreas

New Mexico established an annual record by producing 38,897,741 bbl. of oil during 1940. This was approximately 6 per cent greater than the 1939 production of 36,746,840 bbl. The daily average produc-tion was 106,569 bbl. New Mexico retained its position as the seventh oil-producing state. The recommendations of the United States Bureau of Mines were followed by the Oil Conservation Commission in setting the monthly state allowable. At the beginning of the year the average top allowable for each qc-acre unit was 40 bbl. and at the close of the year it was 36 bbl. Remedial work by the operators has been extremely beneficial and satisfactory in reducing the gas-oil ratios in various fields. Gas formerly blown into the air is now being processed by numerous casinghead plants. The Oil Conservation Commission, with the full cooperation of the Proration Office and operators, has taken bottom-hole pressure surveys and has done considerable remedial work in various fields. Two new oil fields and one gas field were discovered in New Mexico during 1940. Numerous extensions to the existing fields were made. Some of these were definitely wildcats in the same townships designated as fields and some, although called extensions, were more than 3 miles from production. Lea County continued to be the largest oil-producing county in the state, with a production of 33,976,394 bbl. It had the largest number of completions during 1940, with 303 oil wells, 9 gas wells and 13 dry holes—a total of 325 wells. Eddy County was the next most active county, with 239 completions, of which 163 were oil wells, 8 gas wells and 68 dry holes. It produced 4,405,158 bbl. of oil during the year. The increased activity in Eddy County and the completion of a large number of producing oil wells have created a transportation problem that can be solved only by additional pipe-line facilities. During the year Eddy County was unable to produce 1,500,000 bbl. of its allowable oil, because there was no pipe-line outlet. There were 601 wells completed in New Mexico in 1940, of which 478 were oil wells, 22 gas wells and IOI dry holes. This was a decline of approximately 9.5 per cent in the number of completions compared with 1939, when 659 wells were drilled. Southeastern New Mexico Lea County.—The largest producing field in Lea County was the Monument field, with 6,894,475 bbl.; followed by Eunice with 6,559,348 bbl. and Vacuum with 4,743,065 bbl. The Hobbs pool, which for years was the largest producing field in the state of New Mexico, was fourth with 3,790,477 bbl. The Vacuum pool was the most active area, having 68 completions, of which 67 were oil wells and one was a dry hole. Only one new field was discovered in Lea County during 1940; the discovery well was in the Caprock area, the Livermore State No. I, in the SE. 1/4 SE. 1/4 sec. 30, T. 12 S, R. 32 E. This well was drilled to a

Jan 1, 1941

By Charles H. Fulton

FOR some time it has been thought that there should be > closer relationship between the members' of the Institute engaged in education in the mining schools, the mining, metallurgical, ceramic, and geological departments of universities, and the members of the Institute actually engaged in the production of mineral products and the operation and direction of works. The American Society of Chemical Engineers and the American Ceramic Society have for some years past devoted especial attention to the educational matters of their respective fields. The Engineering Foundation, representing the great engineering societies of the country, is deeply interested in technical education and maintains a Committee on Educational Research.

Jan 1, 1932

By H. F. JR. Miller

(Butte Meeting, August, 1913.) THE major cause of the deterioration of the open-hearth furnace as its length of service increases, is the melting down, or rather the slagging, of the checker-brick, together with the deposition of dirt in the form of iron oxide, etc., which helps to close the openings, as well as to slag the brick by chemical action. Any construction that will do away with the necessity of having the waste gases come down through the checkers will eliminate the main reason for their deterioration. There are some other well-defined reasons which are subordinate to the main one given above. Some of the defects of the present type of regenerator chambers are as follows: 1. The checkers cannot be cleaned while the furnace is in operation, nor can they be cleaned at the end of the run without taking out all of the checker-brick. This causes high costs for labor and brick. The labor cost is high because all checker-brick have to be handled twice. The brick cost is high because many of the bricks are spalled in the double handling, rendering them useless because a spalled brick will not stand up. 2. The top courses of brick become coated with iron oxide, etc., melt clown, and large amounts of dirt are deposited throughout the checkers, especially at the bottom. The draft of the furnace is decreased by the closing of the top and bottom openings, especially the top ones, and the entire working of the furnace is affected. If an effort is made to clean the checkers the dirt and brick falling down into the holes still further diminish the draft. 3. The distribution of the air or waste gases through the checkers is in many cases uneven, resulting in a lower temperature of pre-heated air and therefore a slower working furnace. Also, the passage of air and waste gases is so crooked that sometimes the chimney is not powerful enough to overcome the friction.

Jan 6, 1913

By H. R. Ogden, E. S. Bartlett, A. G. Imgram

THE tensile and notch tensile ductile-to-brittle transition characteristics of several refractory metals and alloys have been well documented.1-3 Electron-beam melted tantalum and columbium have been shown to retain excellent ductility at very low temperatures. Some indications of brittle behavior (low ductility and cleavage fracture) were observed with columbium tested at -253oC, but no similar effects were noticed with tantalum. Increasing the interstitial oxygen content in these two materials resulted in the detection of indications of brittle behavior at higher temperatures, although good ductility was retained in both bases at -196°C when they contained about 1 at. pet 0. Detailed descriptions of the impact transition behavior of these two materials at various purity levels have not been available. This technical note describes the effect of interstitial oxygen on the impact properties of wrought, fibered tantalum and columbium and compares the transition behavior to the previously determined tensile transition characteristics. Tantalum and columbium impact specimens with three different interstitial oxygen levels indicated in Table I were tested at temperatures ranging from -196o to 300°C. Oxygen additions were made to 1/2-in.-diam bars of electron-beam melted material in a Seiverts Apparatus. The oxygenated bars were then homogenization-annealed to obtain uniform cross-section hardnesses and swaged to

Jan 1, 1964

By Stanley M. Miller

The probabilistic nature of appropriate geologic variables can be included in analyzing the stability of potential slope failure modes. Random variables in the two-dimensional plane shear analysis of a specified structural discontinuity include the shear strength and waviness angle of the discontinuity and, in some cases, the rock mass density. Estimated probability density functions that describe these random variables are combined by Fourier analysis to produce an estimate of the safety factor probability density function, which appears to approximate a gamma distribution. The probability that sliding will occur along the specified structure is equal to the area under this density function where the safety factor is less than one.

Jan 1, 1982

By AIME AIME

T HE Mid-Continent Section of the Petroleum Division met on Mar. 11 in the engineer's room of the Tulsa Building, Tulsa, Okla., for the purpose of reviewing the papers presented at the annual meeting in New York. L. G. E. Pignell, chairman and delegate to New York for the Mid-Continent Section, read a brief report giving the outstanding features of the various papers that were presented. He expressed regret that more members of the Division could not be present in New York to hear the interesting papers and discussions. It was his opinion that the various remedies presented for overproduction seemed rather theoretical and impractical and he recommended that the engineers come to the aid of some of the economists in giving more practical consideration to the overproduction problem.

Jan 1, 1929

By P. G. Coombs

The kinetics of the cyclic oxidation and reduction processes for palladium powder were examined in the temperature range 848 to 923 K. The changes in oxidation behavior due to cycling are shown to result from the decrease in surface area. Sintering is found to occur only during the reduction process. Oxidation kinetics were found to follow a cubic law with time and yield a relation for the oxidation rate constant of k x = (1.05) 106 exp P74.0). 103 / RT] The kinetics of reduction are demonstrated to be first-order with the rate constant described by the expression: kr = (7.69) 1012 exp [-(208.0) 103 / RT] . In both expressions R is in J.mo1-1.K-1.

Jan 1, 1984

By G. Sachs, E. J. Ripling, S. I. Liu, J. J. Lynch

INTRODUCTION IT is a generally recognized fact that by repeated straining the fracture stress of any metal is reduced to a fraction of its value for static loading. The value of this fatigue strength depends upon numerous factors, such as the states of strain and stress, the limits of straining, and the number of repeated loadings or cycles.1.2,3 The large volume of previous investigations on fatigue is concerned entirely with large numbers of cycles, say exceeding 10,000 and up to 500,000,000. However, the changes in fracture stress and fracture strain occurring after a small number of repeated loadings have attracted little attention. Apparently the only investigations of this type are those byLudwik4,5 who subjected steel, copper, and aluminum wire to repeated torsion. In each test the torque was varied between identical values in the two directions of twisting. Depending upon the magnitude of the moment, fracturing occurred after a number of cycles, up to 10,000. The results of Ludwik's tests will be discussed later. Such torsion does not readily yield actual stress and strain values. Therefore a preliminary study was made of the effects of repeated direct stresses, i.e., tension and compression stresses. Because such tests are considerably more tedious than torsion tests, only high stresses were used in the preliminary work, yielding definite changes in metal properties after a few cycles. It was found in these tests that strains could be controlled more readily than stresses in the investigated range of high stresses. This paper, consequently, deals with the effects of strains of equal magnitude but different signs. The metal was first prestrained in static tension by a certain amount then subjected to compression to yield the same amount of strain after unloading. This loading cycle was repeated up to a maximum of seven times. After various cycles, the stress-strain curves in tension were determined, up to fracturing. As material for these tests, the aluminum alloy 24ST was selected because it exhibits a comparatively small amount of necking in the tension test. This alloy permitted, therefore, rather accurate control at the high strains necessary to produce fatigue failures at less than seven cycles. The results of this investigation appear sufficiently interesting to extend the method of attack in various directions. It is intended to study (I) the effects of cycles up to a few thousands and (2) the effects of strains of different magnitude in tension and compression, respectively. The latter variable also includes as a special case the effects of compressive strains.

Jan 1, 1948

By Sidney H. Haughton

WHEN the white pioneers of the eighteenth and nineteenth centuries advanced from the coastal settlements of southern Africa into the interior of the subcontinent, they found it inhabited, more or less sparsely, by brown or black peoples mainly of pastoral habits but equipped with a fighting spirit and certain fighting weapons. Some of the tribes were smiths, others were miners and metallurgists; all used fuel, either industrially or domestically. Some of that fuel was wood, some cattle dung, and in some places the natives mined outcrop coal. Coal was first discovered by Europeans in Natal about 1840. After proper deliberation and after allowing due time for a consideration of all the implications, the Natal Government decided in 1881 (40 years after) to import an English expert to investigate and report on the discovery. Things then moved rapidly, and in what to a geologist is the remarkably short space of eight years, Natal collieries were producing at the rate of nearly 30,000 long tons per annum or 100 long tons per working day!

Jan 1, 1945

By R. W. Diamond

Three mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd.: (1) The Sullivan Concentrator, Chapman Camp, B. C. (near Kimberley, B. C.), (2) the St. Eugene Concentrator, Moyie, B. C., and (3) the Tadanac (Customs) Concentrator, Trail, B. C. Differential flotation is the only concentration method employed in all three plants. Tables are used for pilot work only. Values in all ores treated are as minerals of some or all of the metals —lead, zinc, gold or silver. Occasional customs ores contain small amounts of copper. Sulfide iron content of ores treated varies from a low figure in some ores to 38 per cent. iron in Sullivan ore. Gangue minerals vary considerably. A few customs ores are somewhat oxidized and as a result present difficulties. Flotation equipment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sullivan Concentrator. In this paper I will not detail treatment nor equipment in any of our plants but will describe special features in, or in connection with, all of them. I will then deal with flotation reagents, describing our use of each of them, particularly where differing from general practice. I will conclude with comments on special subjects related to differential flotation.

Jan 1, 1928

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 Sci- a fourth modification of the original rotating furnace. Its essential fea tures 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 6 are alberene stone. The coil supports D are of ""Formica," a material formed from phe-

Jan 1, 1943

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 Sci- a fourth modification of the original rotating furnace. Its essential fea tures 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 6 are alberene stone. The coil supports D are of ""Formica," a material formed from phe-

Jan 1, 1943