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Jan 1, 1938

By Bradley Stoughton, Henry M. Howe

This paper presents an experimental verification of some of the predictions made by one of us1 concerning the influence of certain conditions of casting upon the size and position of the pipe, and the position of the segregate, in steel ingots. The predictions which we have been able to verify are the following: A. That the pipe is shortened and the segregate raised: 1. By slow casting; 2. By casting with the large end up instead of down; 3. By retarding the cooling of the top, e.g., by means of a sinking-head. B. That the pipe is shortened by slow cooling. C. That the pipe and segregate lie in the last-freezing part. Our procedure was to cast ingots of wax (commercially pure stearic acid) containing a little bright green copper oleate (usually 1.5 per cent.) under varying conditions; to saw each ingot open along a longitudinal plane passing through its axis; and to examine the longitudinal section thus laid bare. In order to make the segregate or enriched part more distinct in color from the impoverished part, a very little red cerasine was added. An experiment which will be described later showed that the cerasine itself does not segregate markedly, if at all. Hence we may assume that the strong contrasts between the green and red shown in so many of our ingots are due, not to segregation of cerasine, but to that of the green oleate, in the wax which in itself is uniformly reddened with cerasine.

Jan 1, 1908

By Albert Sauveur

Iron, like other metals, solidifies through the formation of dendritic crystals; iron alloys forming solid solutions, like other solid solutions, solidify likewise through the formation of dendritic crystals. The alloying elements or impurities as well as the inclusions segregate generally in the interstices, or "fillings," between the axes and branches of the dendrites; that is, in the portions last to solidify. This results in dendritic segregation or heterogeneity, which is generally persistent and makes possible the revelation of the dendritic crystallization of the metal through the selective action of a suitable etching reagent.' For this purpose, a cuprie solution, such as Le Chatelier's, is generally used, copper being deposited on the pure, or relatively pure, ferrite present in the axes while the fillings remain free, or relatively free, from copper deposition. The dendritic structure, formed on solidification in a steel containing 0.50 per cent. carbon, 0.37 per cent. manganese, 0.12 per cent. silicon, 0.07 per cent. sulfur, and 0.035 per cent. phosphorus is shown, after treatment with Le Chatelier reagent, in Fig. 1 under a magnification of 8 diameters. Commercial steel always contains inclusions of manganese sulfide, which are located in the fillings of the dendrites. Comstock has shown that boiling sodium picrate imparts a dark coloration to these inclusions. We find that this reagent likewise reveals dendritic segregations in commercial steel, as shown in Fig. 2, under a magnification of 8 diameters. which represents the same spot as that shown in Fig. 1. The fillings have been darkened while the axes remain white, the action being, therefore, the reverse of that of cupric reagents. On closer examination, under higher magnification (Fig. 3) it is found that the picrate blackens the small particles of manganese sulfide, that these are frequently surrounded by a rim of white, or relatively white, ferrite, and that both the ferrite

Jan 1, 1924

THE problem of reaction rates in the open-hearth process is essentially that of trying to form a fairly clear picture of the "chemical mechanisms" in the bath. Quantitative data on reaction rates would not be very useful even if they were available; however, what few , approximate data there are, can be used in combination with data given in Chapters XVI and XVII to sketch a picture of the "chemical mechanics" of the open-hearth process that is consistent with essentially all the present available evidence. The result may later be found incorrect in many details but even so it will illustrate certain useful methods for obtaining a clearer understanding of the process. As discussed in the last portion of Chapter XIII chemical reactions in general involve the following factors: 1. The reacting molecules are mixed together in space in such fashion as to favor collisions among them. 2. A certain number of collisions occur per unit time among the reagent molecules, depending on their concentration and on temperature. 3. A certain percentage of these collisions result in reaction, these being the collisions between those molecules possessing at the moment energy levels above certain minimum values. The temperature factor enters mainly through (3), and its effect is very marked. (What is called temperature is really the mean energy content of all the molecules of the substance involved; at any one temperature a certain proportion of the molecules will have much higher energy content than the mean value.) Various reaction rates measured at around room temperatures have been found to be speeded from 1.6 to 4.0 times by an increase of only 15 to 20°F., simply because increasing temperature produces a rapidly increasing percentage of molecules with energy levels above the minimum needed to produce chemical reaction in a collision.

Jan 1, 1944

By David A. Thomas, David N. French

The lrnrdness of WC crystals has been measured with the Knoop indenter at loads of 100 and 500 g on the (0001) and (1070) planes. The hardness as tneasitred on the basal plane is 2400 kg per sq mm and shows little anisotropy. The hardness on the prism plane, however, shows a marked orientation dependence, with a low value of 1000 kg -per sq mm when the long axis of the Knoop indenter is oriented parallel to the c axis and a high value of 2400 kg per sq mm when the indenter is perpendicular to the c axis. Slip lines (Ire observed surrounding the microhardness indentations and they show slip on (1010) planes, probably in [0001] and (1120) directions. This slip behavior can be explained by the crystal structure of TVC, which is simple hexagonal with a c/a ralio of 0.976. The hardness anisotropy call be explained by [0001]{1010} and (1130) {10l0] slii) and the resolved shear-stress analysis of Daniels and Dunn. HARDNESS anisotropy is a well-known phenomenon and has been reported for many metals, with both cubic and hexagonal structure.1-6 For hexagonal tungsten carbide, WC, a wide range of hardness values is reported in the literature. For example, Schwarzkopf and Kieffer7 give a hardness of 2400 kg per sq mm and report a value of 2500 kg per sq mm by Hinnüber. Foster and coworkerss give the average Knoop microhardness as 1307 kg per sq mm with a maximum value of 2105 kg per sq mm. Although these values and the structure of WC suggest the likelihood of hardness anisotropy, no such measurements have been made. We first detected a large apparent hardness anisotropy in WC crystals about 75 p large, in over-sintered cemented tungsten carbide. Prominent slip lines also occurred around many indentations. This report presents further observations and interpretations of hardness anisotropy and slip in WC crystals obtained from Kennametal, Inc. Both Knoop and diamond pyramid indenters were used on a Wilson microhardness tester with loads of 100 and 500 g. EXPERIMENTAL RESULTS The carbide crystals tended to be triangular plates parallel to the (0001) basal plane of the hexagonal structure. The side faces were parallel to the ( 1010) prism planes. Specimens were mounted approximately parallel to these two types of faces and metallographically polished. Laue back-reflection X-ray patterns were used to orient the specimens, which werethen ground to within ±1 deg of the (0001) and (1010) planes. The Knoop hardness values measured on the basal plane are plotted in Fig. 1. There is only a small anisotropy, with a hardness range of 2240 to 2510 kg per sq mm. The additional points at angles from 52.5 to 67.5 deg confirm the sharp minimum hardness at 60-deg intervals, consistent with the sixfold hexagonal symmetry. The average hardness of all values obtained on the basal plane is 2400 kg per sq mm. While the basal plane shows only slight anisotropy, the (1010) plane exhibits marked hardness anisotropy, from 1000 to 2400 kg per sq mm. Fig. 2 shows the hardness as a function of the angle between the long axis of the indenter and the hexagonal c axis, the [0001] direction. The minimum and maximum occur when the indenter is oriented parallel and perpendicular to the [0001] direction, respectively. The anisotropy of the prism plane is contrary to that reported for hexagonal zinc and hard- However, the basal-plane anisotropy is similar to these two metals.1'2 To check the accuracy and reproducibility of the measurements, a series of fifteen impressions was made at 100-g load in the same orientation in the same area of the specimen surface. The average for all was 2040 kg per sq mm, with a range of 1950 to 2130 kg per sq mm, giving an accuracy of about ± 5 pct. Thus the slight anisotropy on the basal plane is almost within experimental error. Fig. 3 shows slip lines around the Knoop indentations on the basal plane. The slip traces are in directions of the type (1130). The presence of slip steps on the basal plane indicates that the slip direction lies out of the (0001) plane. Because WC has a c/a ratio of 0.976,' the shortest slip vector is [0001], which suggests slip systems of the type [0001] (1010). Fig. 4 shows slip lines around the Knoop intentations on the (1010) plane. These slip lines are inconsistent with [0001] slip but can be

Jan 1, 1965

By Milton Williams

It is generally recognized that fluid is lost from rotary drilling muds to permeable strata during normal drilling operations;1,2-3 but that this fluid is the filtrate from the mud, rather than the mud itself, has been shown by various workers.1,4,5 The presence of this filtrate in oil-bearing or gas-bearing strata is undesirable and harmful. The decreased permeability of the stratum to oil effected by the presence of water has been pointed out by several investigators,6,7 and since, in the production of the reservoir fluid, the greatest pressure drop occurs immediately adjacent to the borehole, it follows that infiltered water is particularly objectionable in this region. Again, this filtrate tends to make electrical logs less reliable, since oil in the proximity of the borehole is probably flushed out to an appreciable extent by the water.8 Observation of side wall cores may be misleading for the same reason. Drill-stem tests in low-pressure areas may be of doubtful value where no oil is recovered, unless sufficient time is allowed for production of water lost from the mud. The infiltered water may hinder drilling operations by softening shales and causing sloughing; the ['tight hole" occasioned by excessive deposition of filter cake in the hole is a common occurrence. The filter cake remaining on the face of the producing formation may itself sometimes be detrimental to production.9 In view of these implications of the importance of filtration of mud, an investigation was undertaken to determine the factors involved in the infiltration process, and to correlate these in such a manner that the values obtained in routine filter tests employing a conventional filter of the "wall-building tester" type,10 together with data on size of hole, drill pipe, and rate of mud circulation, could be used to estimate water loss and distance of penetration of the filtrate into strata. Quantitative relations of filter-cake permeability, filtrate viscosity, and rate of filtration have been developed for filtration in the simple laboratory filter.4a,11,12,13 It is obvious, however, that the conditions

Jan 1, 1940

By Milton Williams

It is generally recognized that fluid is lost from rotary drilling muds to permeable strata during normal drilling operations;1,2-3 but that this fluid is the filtrate from the mud, rather than the mud itself, has been shown by various workers.1,4,5 The presence of this filtrate in oil-bearing or gas-bearing strata is undesirable and harmful. The decreased permeability of the stratum to oil effected by the presence of water has been pointed out by several investigators,6,7 and since, in the production of the reservoir fluid, the greatest pressure drop occurs immediately adjacent to the borehole, it follows that infiltered water is particularly objectionable in this region. Again, this filtrate tends to make electrical logs less reliable, since oil in the proximity of the borehole is probably flushed out to an appreciable extent by the water.8 Observation of side wall cores may be misleading for the same reason. Drill-stem tests in low-pressure areas may be of doubtful value where no oil is recovered, unless sufficient time is allowed for production of water lost from the mud. The infiltered water may hinder drilling operations by softening shales and causing sloughing; the ['tight hole" occasioned by excessive deposition of filter cake in the hole is a common occurrence. The filter cake remaining on the face of the producing formation may itself sometimes be detrimental to production.9 In view of these implications of the importance of filtration of mud, an investigation was undertaken to determine the factors involved in the infiltration process, and to correlate these in such a manner that the values obtained in routine filter tests employing a conventional filter of the "wall-building tester" type,10 together with data on size of hole, drill pipe, and rate of mud circulation, could be used to estimate water loss and distance of penetration of the filtrate into strata. Quantitative relations of filter-cake permeability, filtrate viscosity, and rate of filtration have been developed for filtration in the simple laboratory filter.4a,11,12,13 It is obvious, however, that the conditions

Jan 1, 1940

By D. L. Martin

The study of cobalt-platinum alloys has been of interest since they represent a class of permanent-magnet material in which the disorder-to-order transformation plays a controlling role. The magnetic properties of alloys in the range 40 to 60 at. pct have been found to be greatly influenced by composition and heat-treatment. The peak properties of 4700 coercive force and 9,000,000 gauss-oersteds energy product were obtained by controlled cooling and aging. These high values combined with ductility and machin-ability give the alloys useful characteristics although their high cost limits their application. THE cobalt-platinum alloys have been of interest in the study of permanent-magnet materials ever since the discovery by Jellinghaus that they had unusually high coerceive-force values.' The high coercive force was associated by Jellinghaus with the disorder-order reaction which occurred in these alloys. This was later verified by Gebhardt and Koster in a detailed study.2 An investigation of the structure, mechanism, and kinetics of the disorder-order transformation and resulting property changes in cobalt-platinum alloys has been in progress for some years. Certain phases of this study related to equilibrium rela- tions, and to the mechanism and kinetics of the ordering reaction have been published previously.3-5 In this paper, the results of the processing and heat-treatment studies on 40 to 60 at. pct CO alloys are presented. The magnetic properties have been found to be influenced greatly by the composition, by the cooling rate from the disordering treatment, and the final ordering time and temperature. Coercive force values, Hc, of 4700 oersteds and energy values, (BH)m, approaching 9,000,000 gauss-oersteds have been obtained by controlled cooling and ordering. PROCESSING OF THE ALLOYS The composition range of interest for permanent-magnet properties centers around the equiatomic composition Copt. In this region the alloys are dis-

Jan 1, 1959

By R. I. Jaffee, F. C. Holden, H. R. Ogden

The properties of quenched Ti-Fe alloys have been correlated with their microstruc-tures. For specimens quenched from equilibrium in the a-ß field, the dominant micro-structural variable is the a-ß ratio. A comparison of specimens having equiaxed a-ß structures with those having acicular a-ß structures shows that the equiaxed specimens have better tensile ductility, but lower impact resistance. There is evidence to show that specimens with acicular structures reach equilibrium in the a-ß field more rapidly than specimens with equiaxed structures. Both strength and ductility are lowered by heat treatments below 700°C. IN previous work,1, 2 certain principles of the physical metallurgy of a-ß titanium alloys have been evolved. Most of these principles have been based on data obtained on alloy systems which undergo no eutectoid reaction, or in which the eutec-toid reaction is so sluggish as to be inoperative. The alloy systems previously studied included the Ti-Mn alloys, with and without a-stabilizing additions, and the binary Ti-Mo alloys. The most important of these principles are: I) The compositional factors which affect mechanical properties are solid solution strengthening, the martensite transformation, and instability of

Jan 1, 1957

By John J. Collins

The plight of the Japanese mining business is pitiful. Coal mines were given the highest priority for all materials they needed, yet between the end of the war and June 1948, the government was obliged to subsidize them to the extent of 22 billion yen, this being the difference between the consumer's price and the producer's price. Most of the metal mining companies have been operating at only one fifth to one third of war-time production rates, and financial losses have been terrific. The chief difficulties have been a plethora of office workers and a dearth of equipment, supplies, and miners. The principal material needs at metal mines are steel rails. cars, plates, nails, rubber hoses, and belting, to say nothing of modern core drills which are totally lacking. Until recently the great shortage was in coal; for lack of fuel the smelters and factories failed to produce the very metals and equipment now needed to operate the mines. Nation-wide shortages have created a monstrous inflation of prices throughout all the economy, currently amounting to 200 times the prewar figures. For example, the price of copper ranged from 500 to 900 yen per metric ton for many years until 1937, but in mid-1948 producers were

Jan 1, 1949

By C. W. Phillips, D. N. Frey

A commercial Ti-Fe-Cr alloy, Ti-150, exhibits a martensitic transformation on cooling and two nucleation and growth reactions, one above and one below the Mg-Mf region, on isothermal holding below the single-phase ß temperature range. The reactions were followed by metallographic, X-ray diffraction, and microhardness methods. THE rapidly expanding engineering application of titanium and its alloys makes increasingly urgent an adequate knowledge of the effect of heat treatment on this material. The work herein reported is an attempt to determine certain aspects of the behavior of a commercially available alloy, Ti-150, during heat treatment. The alloy, with a nominal composition of 2.7 pct Cr, 1.3 pct Fe, 0.25 pct 0, 0.02 pct N, and 0.02 pct C, was received in the as-rolled condition as a 3/4 in. round. Slugs 0.11 to 0.12 in. thick were cut under a coolant using a silicon carbide wheel. Preliminary work established that the alloy consists of two phases, a (hexagonal close-packed) and /3 (body-centered cubic), at temperatures below 1750" to 1775"F, and of only /3 phase at higher temperatures. The slugs were heated for 1 hr in air at 1800°F to form a single-phase /3 matrix, then transferred to molten tin (1250° to 1650°F) or lead (1150°F and below) for isothermal holding. Holding temperatures ranged from 700° to 1650°F, times from 0.001 to 23 hr. The treated slugs were then sectioned, one part for metallographic examination and diamond pyramid hardness, the other, after deep etching to remove the high oxygen surface,' for comparative lattice parameter determination and X-ray phase identification. Hardness measurements were taken on the lightly etched surfaces of the metallographic specimens; a 1000 g load on a 136° diamond pyramid was used. Five impressions on each sample were made and the average of the hardness calculated. The use of microhardness measurements to follow the course of an isothermal transformation reaction is undesirable because of the possibility of wide differences in microconstituent hardness.' They were used in this case, however, because of the small amount of material available. At the higher transformation temperatures, where the above-mentioned objection was apparent, the readings were proportioned to correspond to the estimated ratio of transformed and untransformed constituents present. At lower temperatures, resulting in much finer microconstituents, the microhardness measurements were more uniform. The standard deviation of the mean of five impressions calculated from these latter values was 4.2 DPH. Employing 2a limits (probability 0.95) the experimental error of the hardness measurements averages was 8.4 DPH. The etchant used was composed of one part glyc-erol and one part 48 pct hydrofluoric acid." Of a number of etches tried, this one appeared most satisfactory. All micrographs were taken at 500X magnification and with oblique lighting to permit easier identification of the acicular structure resulting from rapid cooling. No advantage was gained by using polarized light for metallographic examination. Phase identification and lattice parameter measurements were made with a North American Philips high angle spectrometer in conjunction with a recording potentiometer. Considerable difficulty was encountered with some of the lattice parameter measurements because of the extreme broadness of the few diffraction lines obtained from samples consisting mainly of strained, untempered, quenched structures.

Jan 1, 1953

By W. O. Philbrook, H. W. Hosking, N. B. Melcher

Rates and patterns of gas flow in an experimental blast furnace were investigated by measurements, at three levels, of gas compo-sitions and temperatures and by direct determination of gas transit time by a new method employing mercury vapor as a tracer. Infer-ences were drawn about localized reaction zones and the mechanism of the onset of' channeling. LACK of precise knowledge of the nature of gas movement in the blast furnace has always been an impediment to better understanding of the blastfurnace process as a whole. The effects upon operation of various types of charge distribution are very largely brought about by the modifications to gas flow which they occasion. Intelligent evaluation of these effects demands a better understanding of the factors influencing gas flow and the ways in which the flow pattern is altered by conditions existing in the stock column. The same knowledge is required before a fundamental approach can be made to the problem of establishing optimum lines for new furnaces. An experimental furnace is operated at the Bureau of Mines Central Experiment Station, Pittsburgh, Pa. Advantage was taken of experimental operation to conduct an investigation to develop and evaluate methods of study which could be applied later to industrial furnaces. The gas composition and temperature determinations were made as a preliminary study so far as gas flow was concerned but yielded significant information relating to other processes occurring within the furnace. The direct measurement of gas transit times by the mercury-vapor method constituted the major object of the investigation. Development of the mercury-vapor method was carried out while the data on gas composition and temperature were being collected. A complete description of the principle and development of the mercury-vapor method is beyond the scope of this paper but is available elsewhere. The results obtained and some consideration of the method's effectiveness and its potential value in the study of industrial problems will be treated here. DESCRIPTION OF FURNACE The general lines of the experimental blast furnace are shown in Fig. 1. The hearth diameter was 3 ft at the beginning of the investigation, and this was later enlarged to 3 ft 9 in. and finally to 4 ft to increase capacity. Tuyere to stockline height is 21 ft 4 in. The bosh depth is 3 ft 4 in. over which it opens to a width of 5 ft, and this diameter is carried up for 2 ft in a cylindrical section. The inwall batter of 1/2 in. per ft. is considerably less than in larger installations This may have influenced the movement of gaseous and solid materials. The furnace is inside a laboratory building and is charged from outside by a skip and hoist. Feeding into the first of three bell chambers, the stock is distributed by rotating the upper bell, the other two being used to obtain an effective gas seal. Three water-cooled tuyeres, with a nozzle dia-

Jan 1, 1960

[Trans. No,PlaceDate Vol. Page1 1. Wilkes-Barre, Pa*May, '71 13 2, Bethlehem, Pa Aug., '71110 3, Troy, N. Y Nov., '71.. 113 4. Philadelphia, PaFeb,, '72.. 117 5, New York, N, Y.*May, '72,, 120 6. Pittsburgh, Pa Oct,, '72,, 125 7. Boston, Mass Feb,, '73.. 128 8. Philadelphia, Pa,*May, '73., 23 9. Easton, PaOct., '73., 27 10. New York, N, Y Feb., '74,, 211 11. St. Louis, Mo,*May, '74.. 33 12, Hazleton, PaOct., '74., 38 13, New Haven, ConnFeb., '75., 315 14. Dover, N. J,*May, '75.. 43 15, Cleveland, 0Oct,, '75,, 49]

Jan 1, 1928

By G. L. F. Powell, L. M. Hogan

Large degrees of undercooling have been produced in bulk samples, 400 g, of copper and Cu-O alloys by melting in a slag of commercial soda-lime glass. The maximum degrees of undercooling obtained for copper, hypoeutectic and hypereutectic Cu-O alloy samples were 208°, 218°, and 97°C, respectively. No grain refinement as a function of undercooling was observed for the pure copper samples although in Cu-O alloys there was a marked decrease in grain size at degrees of undercooling greater than 150°C. The grain size change is the result of recrystallization during or immediately following the freezing process. THE first report of a large degree of undercooling in a bulk sample of metal was that by Bardenheuer and Bleckmann1 who produced 258°C undercooling in a 150-g sample of iron by melting in a glass slag. Garbeck2 extended this technique to nickel, cobalt, and copper and reported maximum undercoolings of 220°, 230°, and 60°C, respectively, while Fehling and schei13 undercooled a large number of metals as 2 to 20-g samples slagged in glass. Subsequently, one of the authors4 applied the glass slag technique to bulk samples, -500 g, of silver and obtained a maximum undercooling of 250°C. It was concluded that impurities which normally catalyze nucleation at small degrees of undercooling could be removed by oxidation and solution in a glass slag. Large undercooling of bulk samples of iron, nickel, cobalt, and their alloys has also been reported by other authors.8'10'11 Of the five metals mentioned above, copper was the only one which had not been undercooled by at least 200°C in the form of a large bulk sample. Since copper exhibits high liquid solubility for oxygen, as do iron, nickel, cobalt, and silver, it was considered that a much larger degree of undercooling than that observed by Garbeck for copper should be possible. This was obtained by modification of the technique applied previously to silver and the results of undercooling experiments with 400-g samples of copper form part of this paper. The undercooling behavior of Cu-O alloys was also studied, and the influence of a small oxygen content on the grain structure of undercooled copper was observed metallographically. 1) EXPERIMENTAL The copper was obtained as oxygen-free high-conductivity copper, the major impurities of which were Fe 0.01 pct, Zn 0.015 pct, and Si 0.02 pct. Melting was carried out in an open-ended vertical cylindrical fur- nace wound with Kanthal wire. A schematic diagram of the experimental setup is shown in Fig. 1. The undercooling technique previously used for silver4 involved preoxidation of the samples by melting the silver in contact with the atmosphere. The oxygen content was subsequently reduced by freezing the samples under a glass slag, whereby the oxygen was evolved as gas and the continuous glass cover over the surface prevented re-solution of oxygen when the sample was remelted. Since oxygen is not released as gas when a Cu-O alloy is frozen. the technique had to be modified for use with copper. Also, copper is oxidized during fire refining so that an in situ preoxidation treatment of the samples was not considered to be a prerequisite to large undercooling. Experimentation proved that this supposition was correct. Instead, it was found that care was necessary during melting of the copper under glass to minimize oxygen pickup. Samples of copper weighing 400 g were prepared by adding 50-g pieces of copper to a vitreous silica crucible partly filled with soda lime glass at a temperature of approximately 1000°C. Each piece was quickly immersed in the glass slag and held at this temperature until the oxide coating on the surface decomposed. This change was easily observed and coincided with the formation of gas bubbles in the glass

Jan 1, 1969

By I. J. Lin, A. Mitzmager

This paper describes a series of experiments conducted to determine how the physicochemical properties of the suspending fluid affect the size reduction of quartz in a ball mill. Particular attention was directed toward the differences in rate of grinding and particle size distributions when either polar or non-polar fluids were the suspending liquids. Grinding was performed with water, carbon tetrachloride and methylcyclohexane as the liquids, and also in nitrogen for comparative purposes. From the results ob- tained, the authors have concluded that the presence of water greatly enhances efficiency in the grinding of quartz. Comminution is generally regarded as a purely physical process in which fragmentation of a solid is obtained by the application of suitable forces. In 1944, however, Rehbinder et al.1 pioneered the idea that the interfacial forces between the solid and the media plays an important role in comminution. Since then, a number of researches have shown conclusively that comminution is affected by surface chemical phenomena,2-5 and Gaudin went as far as to compare comminution to a chemical reaction.6 The effect of the viscosity and the density of the fluid media in grinding was also investigated, but

Jan 1, 1969

By G. S. Hume

Three provinces in Canada—New Brunswick, Ontario and Alberta— produce oil and gas in commercial quantities. In addition a small amount of oil is being produced and refined in the Northwest Territories at Norman on the Mackenzie River. The production at Norman is derived from two wells drilled by Northwest (Imperial Oil) Co. in 1920 and 1923. The refined products of the oil are used locally in connection with mineral developments on Great Bear Lake. The production of petroleum by provinces and the consumption of natural gas are shown in Table 3. In addition a small amount of natural gas is produced in the southwestern part of Manitoba from shallow wells for local use. Tables 1 and 2 give detailed information. The greatest drilling activity in 1933 in Canada centered around the southern end of the Turner Valley field, Alberta. In addition to several wells previously commenced in this area, eleven new wells were begun. There were three completions to the Paleozoic producing zone in 1933 in the southern part of Turner Valley and one well was abandoned as a result of being off the favorable structure. Of two wells completed in

Jan 1, 1934

CARL A. WENDELL, New York, N. Y. (written discussion*) .-I have never seen in print anything that even remotely has approached this article in clearness and important conclusions in conjunction with work done on the sink-and-float test. I have had many hundreds of these tests made and on different specific gravity solutions and the resultant product analyzed, but I have never grasped nor been able to show what this article sets forth. This article brings out one factor very clearly to my mind; what is to take the place of the solutions of different specific gravities used to obtain the laboratory results, when it comes to washing on a large scale, since water has one constant weight only? The answer is, sizing of coal. And as we know the importance of size versus specific gravity of the material to be washed, perhaps defined (practical) lines can ultimately be gotten up so that the sizing, if any, may be determined at the same time as the laboratory work on the coal is being done. G. R. DELAMATER, ? Steelton, Pa. (written discussion?).-The authors' deductions are well founded and although they disclaim any wide experience in commercial coal washing, practically all of the data presented are applicable to coals of all parts of this country. The paper clearly sets forth the great necessity of careful preliminary investiga-tion of each contemplated washery undertaking and contains the follow-ing very true statements. "It is not safe to assume that any coal which can he successfully washed on coarse coal jigs can be cleaned more com-pletely by washing at a finer size on tables," and "The effect of finer crushing upon the completeness with which impurities may be separated from coal depends upon two opposing tendencies. First, that the more finely a raw coal is crushed, the more completely will the particles of impurities be detached from the particles of clean coal. Second, the finer a coal is crushed the more difficult it becomes to separate the pieces of clean refuse from the pieces of clean coal."

Jan 12, 1919

By A. L. Lee, M. H. Gonzalez, R. F. Bukacek

Experimental viscosity data for methane are presented for temperatures from 100 to 340F and pressures from 200 to 8,000 psia. A summary is given of the available data for methane, and a comparison is presented for that data common to the experimental range reported in this paper. Correlation of the data is presented, and predicted values are given for temperatures up to 460F and pressures up to 10,000 psia. INTRODUCTION The increasing ranges of temperature and pressure at which fluids are produced, transferred and processed in the petroleum and chemical industries stress the need for accurate information on physical properties, both for engineering calculation and for improving the methods used to estimate physical properties. A survey of the literature reveals that disagreements between published data on the viscosity of methane are common and that most investigations have been conducted over restricted temperature and pressure ranges. This situation made it desirable to undertake an investigation with a scope common to most of the literature data available. APPARATUS AND MATERIALS The apparatus used in this investigation was the capillary tube viscometer'described by Dolan,10 with modifications introduced in the general design and operation of the instrument. It has an effective pressure range from 14.7 to 10,000 psia and a temperature range from room temperature to 400F. The design of the viscometer is based on the establishment of a manometric head between two vessels containing the test fluid and a volume of mercury. The reservoirs are connected by a capillary tube through which the test fluid flows and a tube through which mercury flows. A pressure gradient is established by elevating one of the vessels above the other, the resulting flow of mercury displacing the test fluid through the capillary. The schematic diagram of the system (Fig. 1) shows the arrangement of the equipment auxiliary to the viscometer. The density cells assembly (E, Fig. 1) was not used in this investigation since reliable data are available on methane. 23 The assembly consists of a bank of eight 316 stainless steel pycnometers. Experimental values of the density of a natural gas19 and i-butane14 samples have been obtained for pressures up to 8,000 psia and temperatures up to 340F. The methane used was obtained from the Southern California Gas Co. Mass spectrometric analysis showed a composition of 99.8 percent CH4, 0.1 percent C2H6 and 0.1 percent C3H8. EXPERIMENTAL VALUES AND ACCURACY OF DATA Determinations were carried out at several temperatures. With the temperature in the cabinet controlled at a given level, a series of runs were made at various pressures. To establish pressures lower than that obtained from the methane cylinder, it was necessary to vent the gas slowly to the atmosphere until the desired pressure was reached. The consistency of the test run time for a particular condition can be used as a criterion for the accuracy of the data. A further check is obtained by comparison of the viscosity values obtained using different driving heads. To establish the instrument's reproducibility, a large number of runs were made at three completely different conditions of temperature and pressure. Data obtained were analyzed statistically to determine the most reliable value for the variance of the experimental data. It was found that the variances of the data taken at different experimental conditions were not statistically equivalent, but they were small. The largest variance was found at 8,000 psia and 100F, where the standard deviation was 0.385 micropoise. Therefore, 99.9 percent of the data can be expected to fall within 1.15 micropoises of the population mean, except for the intervention of systematic errors in operation.

By Sterling G. Valentine

Until within late years, the preparation of sulphurous ores for the blast-furnace has received comparatively little attention. After the first improvement made on the old style of heap-roasting and roasting between walls, there has followed an almost general adoption of the Gjers kiln or some modification thereof, and the majority of iron-masters have seemed perfectly satisfied with so much progress. However, the Westman kiln was developed in Sweden, and other gas-roasters for sulphurous ores have been since constructed. They are in use on the continent of Europe and in America to a limited extent. The following experiments were made in order to furnish additional information as to the proper conditions for the elimination of sulphur from ores where it is present as sulphide of iron, FeS2 I desire here to acknowledge the Kindness of Dr. Franklin Menges, of the laboratory of Pennsylvania College, at Gettysburg, Pennsylvania, for lending his valuable aid in carrying out a part of these experilnents and analyses. In the first series of these experiments, pure, roughly-pulverized pyrites crystals were used, containing 53.42 per cent. of' sulphur. They were made with a view to determine the effect on pyrites, of heat alone, in various degrees of intensity and duration, air being altogether excluded. The heats at a low temperature were made in glass combustion-tubes, sealed at the end, where the pyrites to be tested were placed, and with only a small opening at the opposite end. Although not allowing circulation, this arrangement still permitted a part of the evolved sulphur to escape. The heats at high temperatures were made in Hessian and graphite crucibles, tightly luted, every precaution being taken to exclude air. The temperatures attained are given approximately, and are as nearly correct as it was possible to estimate them, using Pouillet's scale as a guide.

Jan 1, 1890

By H. M. Fisher, R. E. Snow, S. C. Sun

RAPID colorimetric estimation of the amount of transparent minerals has been applied successfully to instream mill products at the cryolite flotation plant of the Pennsylvania Salt Mfg. Co., Na-trona, Pa. Apparatus used was a Bausch & Lomb monochromatic colorimeter. The optical assembly of the colorimeter, shown in Fig. 1, passes light from a 6-v, 32-cp, prefocus incandescent lamp through two condensing lenses, a heat-absorbing filter, an aperture-control diaphragm, an interference filter, and a sample container. The light finally strikes a barrier-layer photocell and the output current of the photocell is measured by a galvanometer. The engraved index line of the collective lens, located between the lamp and the galvanometer, is imaged upon the transmission scale of the colorimeter by the galvanometer mirror. Reflected light from the galvanometer mirror, the position of which is determined by the output current of the photocell, enables reading of percent transmission throughout the mineral sample being tested. The colorimeter, Fig. 1, was standardized as follows: 1—The colorimeter was' connected to a Sola constant voltage transformer, A, of 6-v output operated from a 110-v ac supply. 2—Turning the toggle switch, C, illuminated the transmission scale, B, and the control knob, D, was adjusted with a blank in the optical system until the hairline on the scale read zero. 3—A No. 430 interference filter, E, was inserted into the filter channel, F. 4—A test tube, G, containing 7 cc of distilled water was pressed into the sample space, H, and the fine adjustment knob,

Jan 1, 1955