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By Will Coghill

FLOTATION has been so closely allied with the sulfide minerals and their early and associated oily reagents that the term "oil flotation" has erroneously been applied to the entire flotation process. Today, the term "chemical flotation" might be used to advantage. Flotation literature has dealt primarily with the removal of sulfides from non-sulfide gangues, and the separation of one sulfide from another. Now, the application of the process to the separation of nonsulfide minerals is coming to the fore; and from the standpoint of the number of commercial minerals involved, the flotation of nonsulfides offers the larger field. Here, soap or soap-forming substances, such as the fatty acids and their derivatives, are used; hence there may well be a subdivision of the chemical flotation process called "soap flotation." Early experimenters learned that it was easy to form a froth or foam that would carry a part or all of the ore charge over the lip of the flotation machine; but this could not be regarded as flotation because of the lack of selectivity. Doubtless soap was one of the first reagents tried, and doubtless it was rejected on account of its gangue-carrying properties. Now this same gangue-carrying ability makes soap an acceptable reagent, for we are dealing with that, which among sulfides, is considered "gan-gue." As in the flotation of sulfides, so in the flotation of nonsulfides, the selective flocculation of the mineral and the dispersion of the gangue are the first objectives. In fact, these two phenomena epitomize flotation. They depend upon the unlike surface properties of the respective miner-als; and as long as the components of an ore have unlike surface proper-ties, a separation is possible, at least in theory. Often in nonsulfide flotation it makes little difference which mineral floats and which is depressed; generally only a separation is sought.

Jan 1, 1932

By Will H. Coghill, J. Bruce Clemer

Flotation has been so closely allied with the sulfide minerals and their early and associated oily reagents that the term "oil flotation" has erroneously been applied to the entire flotation process. Today, the term "chemical flotation" might be used to advantage. Flotation literature has dealt primarily with the removal of sulfides from non-sulfide gangues, and the separation of one sulfide from another. Now, the application of the process to the separation of nonsulfide minerals is coming to the fore; and from the standpoint of the number of commercial minerals involved, the flotation of nonsulfides offers the larger field. Here, soap or soap-forming substances, such as the fatty acids and their derivatives, are used; hence there may well be a subdivision of the chemical flotation process called "soap flotation." Early experimenters learned that it was easy to form a froth or foam that would carry a part or all of the ore charge over the lip of the flotation machine; but this could not be regarded as flotation because of the lack of selectivity. Doubtless soap was one of the first reagents tried, and doubtless it was rejected on account of its gangue-carrying properties. Now this same gangue-carrying ability makes soap an acceptable reagent, for we are dealing with that which, among sulfides, is considered "gan-gue." As in the flotation of sulfides, so in the flotation of nonsulfides, the selective flocculation of the mineral and the dispersion of the gangue are the first objectives. In fact, these two phenomena epitomize flotation. They depend upon the unlike surface properties of the respective minerals; and as long as the components of an ore have unlike surface properties, a separation is possible, at least in theory. Often in nonsulfide flotation it makes little difference which mineral floats and which is depressed; generally only a separation is sought.

Jan 1, 1935

By N. L. Muench, J. S. Osba

Research conducted previously has demonstrated that spectral analysis of gamma radiation from the naturally radioactive elements present in earth materials permits detervination of the relative concentrations of these elements. This research suggested that spectral analysis of gamma radiation resulting from neutron bombardment of elements not nor-mally radioactive might serve to identify these non-radioactive elements, and might permit their quantitative determination. To investigate this possibility, laboratory experiments were conducted in which various earth materials were subjected to bombardment by neutrons from a polonium-beryllium source, and in which the spectra of the resultant gamma radiation were analyzed. The geometry of the lab-ortory system was designed to simulate wellbore conditions. The laboratory work demonstrated that some elements not only can be identified with relative ease, but also can be determined quantitatively. This finding indicates that the use of an intense source of more energetic neutrons may lead to the identification and measurement of additional elements of interest by means of induced nuclear reactions. INTRODUCTION In recent years the applications of nuclear physics to the producing branch of the petroleum industry have become increasingly numerous. One significant development, an outgrowth of nuclear science which is of potential importance in well logging, has been the analysis of gamma-ray spectra of naturally radioactive elements in earth strata. The work of Brannon and Osoba1 has demonstrated that presently available equipment and techniques may be used to determine the relative concentration of thorium, potassium, and uranium in underground strata by means of gamma-ray spectral analysis. Success of the research on spectral analysis of naturally radioactive elements suggested that spectral analysis of induced radioactivity might serve to identify, and perhaps measure quantitatively, those elements which normally are not radioactive, but which become radioactive on neutron bombardment. It was to investigate this possibility that the research described in the following sections was undertaken. THEORY OF INDUCED NUCLEAR REACTIONS Of fundamental importance is the fact that an element, when bom- barded with neutrons, emits gamma rays of energies characteristic of that element. Therefore, in theory, an element may be identified by analysis of the energy spectrum of the neutron-induced gamma radiation. If a neutron impinges upon the nucleus of an atom, any one of several reactions may occur. For identification of elements in earth formations the more important are listed below: 1. The neutron may be elastically scattered, as in a collision between two billiard balls. In this case the total kinetic energy is conserved, and no nuclear radiation is emitted. 2. The neutron may be inelast-ically scattered, as in a collision between two automobiles in which case the total kinetic energy is not conserved. The lost kinetic energy reappears in the form of gamma radiation. 3. The neutron may be captured, in which case the neutron becomes a part of the target nucleus, and a gamma ray is emitted. For example, if the target nucleus is H1, the pro-duced nucleus will be H3, and gamma radiation of a particular energy will be emitted. 4. The neutron may produce nuclear fission, or may enter into miscellaneous reactions which result in the emission of

Jan 1, 1958

By D. M. Buck

greatly restricted and every effort is being made to do away with it where possible, and to substitute a lead-base babbitt or a babbitt with 50 per cent,. tin. The amount of solder having the composition 50 lead, 50 tin, used by the Pennsylvania Lines East, during 1917, was approximately 100,000 lb., but there is reason to believe that a large portion of this can be replaced by a 60-lead, 40-tin solder with satisfactory results, and instructions have been issued to this effect. Inregard to the quantity of new tin used, it is not possible to give the amount, except approximately and from calculations based on the 1917 consumption of bearing metals by the Pennsylvania Lines East only, it is estimated that about 770,000 Ib. of new tin were required in a total of about 21,380,000 lb. of all kinds of bearing metals turned out by the foundry or purchased in the market. No change has been made in the specifications for bearing metals for some years, as the metals used have been satisfactory. A large proportion of the bearing metals are made up from old material re-melted and brought to standard composition by some addition of new metal, and every effort is being made to utilize old material to the best advantage and reduce the amount of new metal of all kinds purchased. For a number of years no tin has been used in the lining metal of either passenger or freight car journal-bearings, except such small amounts as come in from re-melting old linings. No change has been made in phosphor bronze used for rod bushings, as we should expect some trouble from bushings pounding out of shape if a phosphor bronze were used which contained less tin or more lead than the present specifications call for. In this, as well as in the case of all other bearing metals, we expect to use our utmost endeavors to economize and to substitute for tin wherever possible. The Tin-plate Industry D. M. Buck,* Pittsburg, Pa.—During the first 5 months of 1918, approximately 11,000,000 Ib. per month of pig tin were consumed in the United States. Solder, bearing metals, bronzes, etc, used about 5,500,000 lb.; collapsible tubes a little more than 250,000 lb.; tin-foil about 500,000 lb.; and the tin- and terne-plate industry somewhat less than 5,000,000 Ib. In an effort to reduce this consumption and thus conserve our tin supplies, several methods of procedure suggest themselves: 1. Salvage. The most careful and systematic collection and re-use of tin and tin-bearing materials is economically important, in that we thus

Jan 1, 1919

By D. L. Wood

INTERNAL oxidation' is a process in which oxy-gen, diffused into a suitable alloy, causes precipitation of solute oxide particles as the oxidation front moves inward. During an investigation of internal oxidation now in progress it was observed that the grain size is relatively small in thin strip specimens that have been internally oxidized in the as-rolled condition. This may be due to the restraint of grain growth by the precipitated oxide particles. It was observed also that the grain size in unoxi-dized portions of partially oxidized specimens was

Jan 1, 1958

By P. Niessen, S. J. Bercovici

RECENTLY Aust et al.&apos; proposed a model of non-equilibrium grain boundary segregation based on a vacancy gradient induced uphill diffusion process of solute to grain boundaries. According to their proposal, solute atoms which are attracted to vacancies would, during the cooling of a sample, migrate with vacancies toward grain boundaries (vacancy sinks) and thereby enhance the solute concentration in boundary regions. For solute atoms which are not attracted to vacancies no such boundary solute enrichment would be expected. These concepts were given experimental support by boundary and bulk mi-crohardness measurements of various thermally treated dilute zinc and lead alloys and also doped aluminum oxide. The underlying assumption in their work was that solute enrichment in boundary regions is indicated by higher microhardness values. From thermodynamic considerations1&apos;2 it appears that the solid-liquid solute distribution coefficient (K), defined as the concentration of solute in the solid to the concentration of solute in the liquid at equilibrium, indicates whether attractive or repulsive forces exist between vacancies and solute atoms. K < 1 indicates a solute-vacancy attractions, K > 1 indicates no, or a repulsive, vacancy-solute interaction. This note is to report on observations of different grain boundary etching phenomena in high purity zinc alloys. These phenomena appear to depend on whether a K < 1 or K > 1 solute is present. In experiments designed to measure directly the solute enrichment in grain boundary regions, samples of zone refined zinc with 0.1 at. pct solute additions were cooled from 380°C at a rate of 3°C per min. A surface layer of approximately 50 was then removed from the samples by chemical polishing. The samples&apos; surfaces were then protected by a chromating treatment such that in a subsequent etch only grain boundary regions were dissolved. The dissolved regions were approximately semicircular troughs, 10 µ in width. The grain boundaries were usually in the middle, i.e., at the bottom, of this trough. For zinc containing the K < 1 solutes cadmium and aluminum, the grain boundary was always indicated by a ridge as shown in Fig. 1. For pure zinc, and zinc containing the K > 1 solutes copper and gold, a groove at the bottom of the trough indicated the boundary position, Fig. 2., To test if these different grain boundary etching behaviors were possibly connected with the segregation process discussed above, the Zn-Cd alloy was again heated to 380°C and quenched into brine. After surface protection and etching it was found that this specimen no longer exhibited the grain boundary ridges but rather grain boundary grooves as shown in Fig. 2. It would appear, therefore, that the boundary ridge is a consequence of a process occurring during the slow cooling of the samples. From absorption spectrophotometric analysis it was found that for slowly cooled samples containing K < 1 solutes, the solute/zinc ratios of the material from the boundary trough were consistently considerably higher than the solute/zinc ratios of the bulk alloys. This boundary region solute enrichment was not observed in quenched samples. It is concluded therefore, that the boundary ridge shown in Fig. 1 is directly or indirectly connected with nonequilibrium solute segregation.

Jan 1, 1970

Iron and steel lire subjects that will receive the attention clue them at the meeting in. St. Louis. Within the past 2 years the smelting of iron ore on a large scale has been started in the St. Louis area, and the blast furnaces are in full operation. Ore is being received. from the Lake Superior region, in large barges .brought clown the Mississippi River. Firebrick, for the lining of the furnaces, is made in the. St. Louis district to a greater extent than elsewhere in the country. At this meeting, there will probably be a discussion of the possibilities of the increase of manganese production in this country, and of improved methods of using it in steel manufacture.

Jan 10, 1917

By George E. Beavers

It is well to understand at once that converter gas is always mixed with copper blast-furnace gas at Copperhill before entering the Glover tower, and, at times, roaster gas is also added along with the converter and blast-furnace gas. Fig. 1 is introduced to show the variations in the sulfur dioxide content of the gas and the ability of the acid-plant operator to control the variations, resulting in a very even grade at the Gay-Lussac tower entrance. The sulfur dioxide content of the gas entering the Gay-Lussac tower must be low and regular to assure low niter consumption. The blast-furnace gas alone is rather uniform as regards sulfur dioxide content and the variations, as shown in Fig. 1, are chiefly caused by converter changes—out for charging, slag pouring, copper pouring, and, of course, the "finish." The combined gas during the converter finish is, at times, almost free of oxygen and the sulfur dioxide content reaches 13.0 per cent. At such times air is added at the Glover tower.

Jan 1, 1934

By Ernest Stütz

(New York Meeting, October, 1918.) THE problem of increasing blast: furnace efficiency through diminution of flue-dust production while operating with burdens consisting largely of fine ores has of recent years attracted the attention of metallurgists, whether directly or indirectly interested in the economies of iron smelting, and the various methods evolved from theory or practice have been submitted to wide discussion. After the very thorough and, at that time, exhaustive view of the whole subject, which was afforded to the industry by the meeting of this Institute in February, 1912, the subject was again taken up at the meeting of the Verein deutscher Eisenhüttenleute at Diisseldorf in December, 1912. While American and German conditions are not entirely identical, it may be of interest to give here the words of the gentleman summing up the discussion at the Diisseldorf meeting: &apos; The chief advantage offered by the use of briquettes lies in the fact that disturbances in the furnace, caused mostly by the presence of fine ores in the burden, are avoided, and that blast pressure can be considerably reduced. The resulting economies cannot be overrated, as, with lower blast consumption per ton of product, the installation will be able to take care of increased production. In consequence of lower pressure and speed of blast, heat is more efficiently utilized, flue gas temperature is lowered, and coke particles are less liable to be carried along with the flue dust, of which considerably less is produced. Finally, by increased regularity of operation and higher . temperature in the lower parts of the furnace, the quality of the product is improved. The question of briquetting iron ores has grown to be one of the most important in the iron industry, and, it is not any more a question of what is the cost of briquetting ton of ore, but what, in using ore briquettes, is the cost of production of a ton of iron.&apos;

Jan 7, 1913

By W. T. Cardwell

This paper presents a theory for estimating the rate of gravity drainage of a liquid out of a sand column. Account is taken of the variation in permeability to the liquid as the saturation in the upper part of the sand becomes less than 100 pct. The theory is confirmed by previously published experimental data. Introduction Petroleum engineers have expressed the need for 4 theory of gravity drainage. Brunner,&apos; in particular, has pointed out that some type of mathematical theory is necessary to begin the application of laboratory data to field problems. Muskat and his associates2&apos;3-4 have recently made contributions to the theory of gas-drive behavior and have indicated an intention to apply their methods to water-drive systems. No theory of gravity drainage rates has been developed, however, and it seems desirable to formulate one at this time. Differential Equations of Capillary Flow The flow of liquids in partially saturated porous media has been studied by many investigators.6-10 Richards6 presented derivations of fundamental differential equa- tions governing two-phase capillary flow; and used simplified forms of those equations in solving a steady-state problem. Muskat and Meres6 presented and used equations different from those of Richards. Their equations did not explicitly involve capillary pressure gradients; but included, on the other hand, terms expressing the effects of the evolution of gas from the liquid phase during flow. Leverett8 stated in 1940 that "previous work on the flow of fluid mixtures in porous solids [had] failed adequately to account for all of the three influences that cause motion of the fluids: capillarity, gravity, and impressed external pressure differentials." Leverett&apos;s basic equations, however, were specialized forms of the general equations of Richards,5 which had actually taken account of the three influences mentioned by Leverett, but had not been used in a problem involving all three. The fact is that our knowledge of capillary flow and our ability to express this knowledge in differential equations exceed our ability to solve the equations except in a few cases. General differential equations have usually been of little more than formal value. In solving practical problems, it has been necessary to develop specific equations, preserving terms that involved the factors important in those problems, and purposefully neglecting other terms that were not of predominating influence. This is the method followed here. It is believed that the solution of the particular problem and the scheme of the solution itself are new.

Jan 1, 1949

By Louis V. Bender

AfteR investigating the work of coal-dust fired reverberatories of the Canadian Copper Co., at Copper Cliff, Ontario, the management of the Washoe Reduction Works decided to experiment with and ascertain the advantages of using coal dust as a fuel in their reverberatories. Consequently, during the month of June, 1914, reverberatory furnace No. 8 was changed in order to use powdered coal as a fuel. The results obtained by this method of firing are gratifying and show a decided saving in cost of smelting as compared to grate firing with lump coal. The furnace, as remodeled, is 124 ft. long by 21 ft. wide, and varies in height from 8 ft. 6 in. at the back end to 5 ft. 7 in. at the skimming end. The general construction of the furnace is similar to that of the other furnaces at this plant. There are no side doors to this furnace, as it was thought that with the present arrangement for feeding no "fettling" or "claying" would be required. The interior of the furnace can be inspected through the burner port holes, after shutting off the burners and giving a few seconds&apos; time for the gases inside the furnace to clear away. The charging is done on either side of the furnace from longitudinal hoppers, extending a distance of 74 ft. from the back end of the furnace. Leading from the hoppers into the furnace are 6-in. pipes, spaced 191/4 in. apart, through which the charge is intermittently dropped. The charge is kept well above the slag line at all times; in this way the side walls are protected and no fettling is needed on this portion of the furnace. The remainder of the furnace requires fettling. After operating for three months, we found that the bricks were eaten into along each side wall from the skimming door back to the point where the charge had been dropped. The depth of this cutting away was 8 in. close to the front end and gradually tapered to zero at a distance of 50 ft., and was greatest on the side of the furnace having the larger flue connection. Hoppers will be put in for the entire length of furnace, from which fettling material will be dropped, to prevent this cutting. After the run of three months, the roof was in excellent condition. At the back of the furnace the bricks were not cut into at all; at 30 ft.

Jan 1, 1915

By C. M. Signer, W. P. Hewitt

THIS is a story of a mine discovered in the days of the Conquistadores but that remained unimportant until the second decade of this century. Without the usual legendary history of romance and fabulous riches it has become famous for the development of unexpected metals and unusual problems. These developments and experiences, exciting and interesting as any legend, are the substance of the San Antonio mine of the Santa Eulalia district in northern Mexico. Originally opened for its silver-lead content, it developed a tin deposit of singular economic importance and unique geologic interest, a vanadium orebody that for a few years placed it among the leading vanadium producers of the world, and now lead and zinc sulphide ores. It has been the seem of a disastrous flood that brought deep-sea divers into Mexico&apos;s desert mountains and raised important problems regarding ground water, demanding unusual measures. Geology and operating questions relating to the above matters will be discussed and much of it is recent history which has become a part of Mexican mining lore. History Dates Back to 1325 Santa Eulalia is the oldest of American cities, founded in 1325 by the Aztecs under the name of Tenochtitlan and devastated in 1521 by Cortes and his rapacious band of iron-willed adventurers. Their lust for gold burned through the Aztec empire and onward into most of North America. Santa Eulalia was in the path of conquest. In 1591 the district&apos;s first ore discovery was made near what is now the San Antonio mine. The ores carried no gold and the silver-lead content was unattractive to the early pioneers. Not until 1700 was real mining activity undertaken.

Jan 1, 1952

By Lawrence Adler

MINE hoist ropes have hitherto been selected by successive approximation, a process both tedious and inexact. The proposed expression is a readily solved synthesis of existing data and the following standard equation:&apos; [ W + Wr + (W + Wr) -a 9 (W + W)f + b] n=T [1] For convenience, a glossary of all terms appears on page 564. Since rope weight (W,) and bending load (B) are functions of unit rope weight (Wv), which in turn is a function of rope strength (T), W, and B can be expressed in terms of T. W, as a Function of T: A study of the curve in Fig. 1, unit rope weight vs strength, yields Eq. 2: W. = -f- [2] Therefore Wr = WvL = T. [3] iv B as a Function of T: From Fig. 2, unit rope weight vs diameter, Eq. 4 is obtained: W, = 1.6d2 [4] B is related2 to d and D, and d has been expressed in terms of W, by Eq. 4, so the curve B vs W, (Fig. 3) gives Eq. 5: 177,000 177,000 This may readily be checked from the expression3 for a 6x19 rope, i.e., d3 B = 288,000D Since d2 = 0.625 W, and N = substituting d into the above expression gives Ea. 6: 180,000 180,000 B T, which will be used. [6] Into Eq. 1 substitute Eq. 3 and Eq. 6, noting that f=0.02: W + T 1.02+=T. [7]

Jan 1, 1958

By C. Dean Starr

The physical basis of the equation correlating electrical conductizlity and temperature coefficient of resistance of solid solution alloys has been inzlestzgated and the nature of the constants evaluated. It is shaun that the same form of correlation is valid irrespective of the magnitude of the temperature coefficient. However, the effect of therma1 expansion and change in resistivity with temberature nust be considered when the magnitude of the temperature coefficient of resistance is near zero. In a comprehensive literature survey conducted at the Armour Research Foundation in 1950, it was found that a linear relationship exists between the electrical conductivity, K, and the temperature coefficient of resistance, a, for solid solution alloys. This was expressed by the equation where B, a constant, depends on the solvent metal but not the solute. A continuing investigation by Hansen, Johnston, and Parks showed this equation was generally appropriate for Cu, Ag, Au, Pd, Pt, and Co base binary solid solution alloys as well as for many ternary alloys of copper over a range of conductivities and temperature coefficient of resistances from 0.02 to 0.60 reciprocal pohm cm and-0.00015to0.004Q per 0 per "C respectively. Eq. [I] was not always valid for alloys that exhibited a change in state (magnetic to nonmagnetic) or for alloys that had a temperature coefficient of resistance near or below zero. For example, in nickel alloys, a simple linear curve as predicted by Eq. [l] was not obtained when the conductivity was plotted against the temperature coefficient of resistance. Hansen suggested that deviations observed were caused by transitions from a ferromagnetic to a nonmagnetic state. Subsequent and more extensive data by ronin on Ni-Mn alloys confirmed Hansen&apos;s postulate. While both states independently showed a linear relationship between K and a, the value of B was different for the two states. In some copper and gold base alloys, as well as the platinum and palladium alloys investigated by Hansen, the conductivity did not extrapolate to zero at zero a as demanded by Eq. [I]. This deviation can be readily corrected by simply adding a constant to Eq. [I.] whence Eq. [2] shows the K decreases as a decreases but that K has a positive value when a = 0 which is observed for commercial solid solution alloys as well as the experimental alloys tested by Hansen. While other methods of correlation of electrical properties have been made such as the one by Starr and Wang3 who found a linear relationship between resistivity and temperature coefficient of resistance for Ni-Cr-Al-Cu alloys, the data, in general, can also be correlated by a form of Eq. [2]. Thus, Hansen&apos;s empirical equation has considerable merit. The objective of this paper is to determine the physical basis for this equation and to examine the region near zero a in more detail. ELECTRICAL CONDUCTIVITY VS TEMPERATURE COEFFICIENT OF FU3SISTANCE The resistance of a metal or alloy is defined as

Jan 1, 1963

By C. Norman Cochran

The pllnse diagvam for the NaF-AlF3 system was used to calcutate an ionic model for the NaF-AlF3 system. Assuming an ideal solution,a series of simultaneous equations expressing equilibria be-tween solid and liquid phases at the euleclic, perilec-tic, and melting points were solved for the activities of the ionic species, the dissociation constants, and the entropies and heats of fusion. The calculations suggest the existence of A13F1415 ions in addition to the F-1+AlF6-3 , and AlF4-4 ions previously proposed by others. The calculaled valnes give better agreement with vapor pressures than the previous model without Al3Fl14-5. Additional possible vefinements of the model are proposed. CRYOSCOPIC1 investigations and density data2 for the NaF-A1F3 system have previously been used to study the dissociation mechanism of Na3A1F6 and to derive equilibrium constants for its dissociation to NaF and NaAlF,. Depending primarily on the heat of fusion assumed for cryolite, the dissociation constants ranged between 0.02 and 0.18 from cryoscopic studies, and from 0.09 at 1273°K to 0.16 at 1363°K from density data. In most cases the values were unable to reproduce satisfactorily the experimental liquidus lines very far on the A1F3 side of the Na3A1Fe composition. This suggested the existence of at least one other ionized compound in the melt besides NaA1F4 in the Na3A1F6-A1F3 side of the system. This is assumed to be liquid Na&13F14 (chiolite), which is already established as a stable solid in phase studies of this system. MODEL FOR THE MELT The melt is assumed to be an ideal solution with ion activities equal to anion fractions. The only cation in the model is sodium so that Temkin and simple anionic activities are identical. Although the compounds are completely ionized to Na&apos; and the respective anion in the melt, molecular rather than ionic notation is used throughout this work. The Na3A1Fe is assumed to dissociate to NaA1F4 and NaF as in the former model, and Na&13F14 to dissociate to Na3A1Fe and NaA1F4. Other valid dissociation equilibria can be written involving these four compounds, but all of these can be obtained by combinations of the two described dissociation reactions and, thus, are automatically considered in these calculations. The model allows for no free AlF3 so that compositions for NAIF3 > 0.5 (mole fraction A1F3 on the NaF-A1F3 basis) cannot be treated. The question of the existence of free AlF3 in the melt will be discussed again later. The constants in the model were evaluated from points along the entire known liquidus line of the NaF-A1F3 system. Previous work employed only the liquidus line or densi- ties near the Na3A1F, composition. The liquidus line compositions used in the solution of the model are from unpublished work by Mr. P. A. Foster, Jr., for compositions between the Na3A1F6 melting point and the Na&13F14-A1F3 eutectic, and from the published works of Grjotheim,1 Phillips,3 and Foster4 for the remainder of the system. The relationships used in solving for the desired dissociation constants and heats and entropies of fusion are listed in Table I, and the points along the liquidus line at which each apply are indicated to the right of the relationships. The mole fractions of each of the separate species in the melt are symbolized by N. Relationships [I] and [2] are the respective dissocia-ation constants, Kl and K2, of Na3AIF6 and Na5A13F14 for this model. For simplicity, these constants will be assumed to be independent of temperature. Relationship [3] follows from the assumption of the ideal solution. The expression relating the values of N to the experimental values of NAIf3, is given in Relationship (41. Relationships [5], [6], and [7] each state the equilibrium between a compound in the melt and its pure solid phase for the portion of the liquidus lines where it precipitates. The heats of melting, AH,, and entropies of melting, AS,, used in [5], [6], and [7] are assumed to be independent of temperature. The compositions and temperatures of all five invariant points (two melting points, two eutectics, and one peritectic) along the liquidus lines from NAIF3 = 0 to NAIF3 = 0.5 were employed in the solution. The eutectic and peritectic compositions were particularly useful because each of these is involved in one more equation than other points along the liquidus lines and thus reduces the number of points required to solve for the constants. Also, their use assures that the inflection points in the derived liquidus line will correspond exactly with those on the experimental liquidus line. The total number of equations is 5k1 — 1, where n is the number of experimental composition points used. The number of unknowns is 4n + 5 (4n- 3 values of N, 3 values each of AH, and AS,, and 2 values of K). Thus, six points must be used in the solution to obtain an equal number of equations and unknowns. The one additional required experimental composition was taken on the liquidus line between the Na3A1Fe melting point and the Na3A1F6-Na5A13F14 peritectic. Previous work indicated this was a difficult portion of the curve to fit. The temperature used for the point was 1161°K, the same as for the NaF-Na3A1Fe eutectic. This choice of temperature gave two points with identical NNa3AIF6 values which simplifies the algebraic solution. The second point at this temperature is denoted 1161°&apos;K. PROCEDURE FOR SOLUTION OF EQUATIONS Values were assumed for NNa,AIF and NNaF at the NaF-Na3A1F6 eutectic at 1161°k. By an iterative procedure, the corresponding values for NNa5A13F14 and NNaAlF4 at 1161°K were determined from 131 and 141. A value was assumed for NNaAlF4 at 1161°&apos;K and

Jan 1, 1968

By T. L. Joseph

THE United States Bureau of Mines has been studying the blast-furnace process for, about ten years. An experimental furnace was developed by the bureau in cooperation with the Minnesota School of Mines Experiment Station, University of Minnesota. Many data have been obtained and published.1 Royster, Joseph and Kinney§(48) found that the particle size of ore had an important effect upon the blast-furnace, process. Kinney(28) stated: Economy in blast-furnace practice depends largely upon efficient gas-solid contact in the shaft of the furnace. If efficient work is not done in the shaft, the hearth and bosh will not function properly. A condition may be readily imagined where the particles of ore in the shaft are so large that the time entailed in the descent of these materials into the bosh is not sufficient to permit proper reduction and preparation prior to the time the ore enters the bosh of the furnace. Another condition may be pictured where the density of the stock column and the flow of stock is such that the ore will take one course and the gas another. Both of these examples will result in insufficient contact between the gas and the ore. Unreduced ore will reach the hearth, and the gas which has not been efficiently oxidized will reach the stock line. The result is the use of an excess of carbon in the smelting process. It is obvious that fine ore particles occurring in the ore as charged, or . formed in the furnace due to heat and mechanical action, place a definite limitation upon the efficiency of the operation. There is also an economic loss of fine material as dust.

Jan 1, 1930

By Carlton Beal

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

Jan 1, 1946

By Carlton Beal

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

Jan 1, 1946

By J. H. Brophy

Experimental evidence in recent years shows that nickel coated hydrogen reduced tungsten powder can be sintered to 98 pct of theoretical density at 1100°C. New data indicate that the sintering rate is the same for nickel contents ranging from 0.125 wt pct (mon-atomic layer) to 5.0 wt pct Ni coated on 0.561. tungsten powder. Nickel tungsten made by coreduction from oxides sinters in a kinetically similar way, but the rate tends to increase with higher nickel contents. The activation of sintering can be accomplished with a minimum amount of nickel if coated powder is used. Transverse rmpture strength was found to increase in specimens containing 0.25 pct Ni as density increased during the initial stage of the carrier-phase sintering process. Upon the onset of grain growth in the final stage, strength was found to decrease. With increasing nickel contents up to 4 pct, strength increased. Maximum strengths in three-point loading were observed at 73,000 psi for 0.25 pct Ni and 93,000 psi for 5 pct Ni. These were comparable to that of massive tungsten recrystal-lized in the presence of nickel and tested in the same way. The results were sensitive to the mode of powder treatment and ductility was negligible in all cases. The study and application of sintered bodies of nickel and tungsten is not new; however, the analysis of the mechanism by which small additions of nickel increase the sintering rate of tungsten promises to Contribute new information regarding sintering theory in general. Initial experimental evidence was presented by the authors showing that nickel-coated hydrogen-reduced tungsten powder may be sintered to 98 pct of theoretical density at 1100°C in 16 hr.&apos; Simultaneously, a kinetic analysis of the process showed that it took place in two distinct stages. In the first stage, nickel evidently served as a carrier phase through which tungsten atoms could move. This stage was kinetically similar to the &apos;solution-precipitationo step postulated when the carrier phase is liquid3 although in the nickel tungsten case, there is no evidence of the existence of a liquid phase either in equilibrium phase relationships or in mi-crostructures at the temperatures under consideration. In the present work, new data for nickel-coated tungsten powder are offered in support of the proposed mechanism, and a more explicit study of the second stage of densification is presented. Concurrently, the sintering kinetics of these coated powders are compared to Ni-W powder made by coreduction of oxides. In this way the present work can be compared to earlier results in nickel activated sintering of tungsten in which the coreduction process was emplyed. The ultimate utility of such an activated sintering process will be determined to some extent by the mechanical and physical properties of the final prod-

Jan 1, 1962

By Shrikant Lele

INTRINSIC and extrinsic stacking faults may be formed in fcc structures by similar processes with bounding S-and D-Shockley partial dislocations respectively.&apos; The only difference between these two dislocations is that the side on which the fault lies is reversed. The number of nearest and next nearest neighbors of atoms is identical for the two faults, but that of next next nearest neighbors is different. Thus, the energies associated with intrinsic and extrinsic faults may be expected to be different but of the same order of magnitude. An extrinsic fault can be constructed from two intrinsic faults on adjacent close-packed planes. This suggests that the extrinsic fault energy is higher than the intrinsic fault energy. It is, therefore, surprising that extrinsic faults have not been detected in X-ray studies2 of deformed alloys of low stacking fault energy. These have, however, been observed in cerium3 by X-ray diffractometry and in Au-4.8 at. pct Sn4 and Cu-16.6 at. pct A15 alloys by transmission electron microscopy.

Jan 1, 1968