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By W. Luyken, E. Bierbrauer

A number of articles have been published, notably those by R. S. Handy, R. T. Hancock and A. P. Watt in Engineering and Mining Journal, dealing with the calculations involved in ore dressing. These publications demonstrate both the importance of the subject and the lack of success in developing a generally recognized method for comparing enrichment effects. Considering that we may wish to compare enrichment results on similar or dissimilar ores, that we may desire to make the comparison on the basis of either the absolute or the economical efficiency, and that the number of factors upon which the result depends is large, the question arises whether it is possible to set up a positive method for such calculations. In the following pages it is our aim to show that a sure, complete and successful way to overcome existing difficulties has been found. Graphical Analysis of Ore-dressing Processes The following is from Truscott's Text Book of Ore Dressing (London, 1923): x = assay of ore treated (feed). y = assay value of the concentrate. 2 = assay value of the tailing. a = weight of feed. 6 = weight of concentrate. c = weight of tailing. C = fractional concentration = = . a y - z K = ratio of concentration = 1/c a/b = y-z/x-z 2 B = fractional recovery = 9 = C y/x (3) 100R = percentage recovery. Copt. = theoretically best concentration. 100 — Copt = waste in the feed.

Jan 1, 1930

By W. Luyken

A NUMBER of articles have been published, notably those by R. S. Handy, R. T. Hancock and A. P. Watt in Engineering and Mining Journal, dealing with the calculations involved in ore dressing.. These publications demonstrate both, the importance of the subject and the lack of success in developing a generally recognized method for comparing enrichment effects. Considering that we may wish -to compare enrichment results on similar or dissimilar ores, that we may desire to make the comparison on the basis of either the absolute or the economical efficiency, and that the number of factors upon which the result depends is large, the question arises whether it is possible to set up a positive method for such calculations. In the following pages it is our aim to show that a sure, complete and successful way to overcome existing difficulties has been found. GRAPHICAL ANALYSIS OF ORE-DRESSING PROCESSES The following is from Truscott's Text Book of Ore Dressing (London, 1923) x = assay of ore treated (feed). y = assay value of the concentrate. z = assay value of the tailing. a = weight of feed. b = weight of concentrate. c = weight of tailing. C = fractional concentration = b/a= x-z/y-z (1) K = ratio of concentration = 1/C = a/b =y-z/x-z (2) R = fractional recovery = yb/xa = Cy/x. (3) 100R = percentage recovery. Copt = theoretically best concentration. 100 - Copt = waste in the feed.

Jan 1, 1929

By John W. Pack

AT present the manufacture of metallic zinc, or spelter, in Missouri, is carried on only at the establishments located at Carondelet, or South St. Louis. Although the development of the industry has not yet reached that fulness which it has attained elsewhere in the United States, still the commanding advantages of position of these establishments are so evident that the prospective importance and magnitude of spelter manufacture in this State, and especially at this locality, can hardly be doubted. A study of the chemical and technical aspects of the business of these points cannot be without interest to the metallurgist as well as to the capitalist. I have endeavored to investigate, as far as was practicable, within the limits of a paper of this character, some of the problems connected with this industry, at the same time making a few comparisons of the results attained at some of the Carondelet works with those of other establishments with regard to which information could be obtained. In the prosecution of these studies I have been kindly aided by the managers of Carondelet establishments, and by Prof. Charles P. Williams, Director of Rolla School of Mines. To the latter I am especially indebted for assistance in regard to methods of analysis. To all these gentlemen I return my thanks for their valuable aid. Other sources of information will be duly credited in their proper places.

Jan 1, 1875

THE first session of the Institute was held in the hall of the Washington University, Wednesday evening, May 27th, President Raymond in the chair. After the address of welcome by Hon. Thomas Allen, and the reply of Mr. Raymond, the following names were presented for election as members and associates, duly indorsed by the Council. They were unanimously elected : *Henry Booth, - New York City. *Charles H. Morgan, - Worcester, Mass. *Howard Painter, - West Chester, Pa. *Dr. M. J. Goodfellow, - Eberhardt, White Pine Co., Nevada *Otto Wittelshach, - Eureka, Nevada. *John T. Williams, - New York City. †Charles A. Young, - Philadelphia. *Charles E. Stafford, - Boston, Mass. *Arnold Hague, - Orange, N. J. *Richard Pearcé, - Black Hawk, Colorado. *W. R. Maffet, - Wilkes-Barre, Pa. *Prof. George A. Koenig, - University of Pa., Philadelphia *Prof. R. Nutting, Jr., - Indianapolis, Indiana. *Edwin Mickley, - Hockendauqua, Pa. *G. C. Broadhead, - St. Louis, Mo. *Dr. Adolph Schmidt, - St. Louis, Mo. *Alexander Leonhard, - St. Louis, Mo. *Edward D. Meier, - St. Louis, Mo. *John W. Meier, - St. Louis, Mo. *Prof. Forrest Shepherd, - St. Louis, Mo. *Edward Walsh, - Pilot Knob, Mo. *George Riggs, - St. Louis, Mo. †Col. Chas. B. Parsons, - Cadet, Mo. † W. A. Scott, - Mine La Motte, Mo. *Prof. Paul Schweitzer, - Columbia, Mo. *William E. Guy, - St. Louis, Mo. †William Harris, - St. Louis, Mo. *Henry Black, - Pittsburgh, Pa. †W. Noyes, - New York City. *W. Lorenz, - Philadelphia. †E. A. Whetmore, - New York City. * Members. †Associates.

Jan 1, 1875

By John W. Pack

At present the manufacture of metallic zinc, or spelter, in Missouri, is carried on only at the establishments located at Carondelet, or South St. Louis. Although the development of the industry has not yet reached that fulness which it has attained elsewhere in the United States, still the commanding advantages of position of these establishments are so evident that the prospective importance and magnitude of spelter manufacture in this State, and especially at this locality, can hardly be doubted. A study of the chemical and technical aspects of the business of these points cannot be without interest to the metallurgist as well as to the capitalist. I have endeavored to investigate, as far as was practicable, within the limits of a paper of this character, some of the problems connected with this industry, at the same time making a few comparisons of the results attained at some of the Carondelet works with those of other establishments with regard to which information could be obtained. In the prosecution of these studies I have been kindly aided by the managers of Carondelet establishments, and by Prof. Charles P. Williams, Director of Rolla School of Mines. To the latter I am especially indebted for assistance in regard to methods of analysis. To all these gentlemen I return my thanks for their valuable aid. Other sources of information will be duly credited in their proper places.

By John A. Hansuld

Molybdenum presents a series of baffling geo- chemical puzzles. It can exist in six different valence states, possessing three different coordination numbers. As a result, it combines with other elements to form a wide variety of negatively and positively charged ions and complexes whose exact chemical nature are relatively unknown. Its rather complex chemistry might be described as "ambidextrous, bi-sexual and polygamous". It is little wonder then that the geochemistry of molybdenum is relatively unknown, and compared to most common metals its geochemical behavior is somewhat unique. The behavior of a particular element or metal, such as molybdenum, in a given dispersion media is largely controlled by the stability relations among its various oxidation products. Recognition of these products and an understanding of their stability relations is therefore a prerequisite to a proper understanding of its observed behavior. Because most secondary dispersion media represent aqueous chemical systems, stability relations are best expressed as functions of Eh and pH.

Jan 12, 1966

By W. A. Boyer

If the safety factor of a mine hoisting rope is checked for the lowest depth, is the rope then safe for all levels? The answer here is no. A new set of volues is proposed. HOISTS for metal mines are seldom designed for one particular depth. They are intended for an ultimate load and depth with a given speed but are first used to hoist from a shallower depth, gradually working to the ultimate as development progresses. Sometimes the mine is not worked on the upper levels because of the kind and grade of ore, the mining of which depends on market conditions. In this case the hoist may be used in the same working shift to lift ore, for example, from the 1200 and the 4400-ft level. This means that the safety factor of the rope should be considered not only when it hoists from the greatest depth, but also when it hoists from the upper levels. According to present safety factor standards, a hoisting rope can have ample safety margin when hoisting from the lower or lowest level and still be shy of sufficient safety margin when hoisting from the upper levels. This will be shown by curves presented in this paper. The safety factor of a hoisting rope as defined by the U. S. Bureau of Mines' is the ratio of the static load to the tensile strength of the rope. It is calculated by dividing the breaking strength of the rope* In Fig. 1 curves A and B are plotted against the vertical suspended distance, which is the abscissa, and the factor of safety, the ordinates. Curve C is a smooth curve drawn through the midpoints of the steps of curve A and would more closely represent the minimum factor of safety for new rope for any particular depth. Curve D is a smooth curve drawn through the midpoints of the steps of Curve B and would more closely represent the minimum factor of safety when ropes should be discarded for any particular depth. If a new rope were applied with a minimum factor of safety, then the vertical distance or ordinate under curve D for any particular depth, divided by the vertical distance or ordinate under curve C, would represent the minimum percent of remaining area intact that could be allowed before the rope would be discarded. Also, that section of the ordinate between curve C and curve D is proportional to the section of the area of the new rope that could be allowed for wear and broken wires. Considering that point at 2500 ft on the chart, the ratio do to co would be the minimum percent of rope area remaining at the point of discard. The ratio of that portion of the ordinate cd to co would represent maximum percent of area of a new rope available for wear and broken wires.

Jan 1, 1955

By H. R. Thresh, A. F. Crawley, D. W. G. White

The densities of liquid tin, lead, and Sn-Pb alloys have been measured over a range of temperature above the liquidus. In all cases, data can be adequately represented by an equation of the type p = a + bT. For pure tin, the values of a and b are, respectively, 7.139 and 7.125 x 10-4, and for pure lead, 11.060 and 12.220 x 10-4. At constant temperature, molar volumes in the Sn-Pb system vary linearly with composition. DURING the course of a long-term program at the Department of Energy, Mines and Resources, Ottawa, Canada, the densities of liquid tin, lead, and Pb-Sn alloys were studied. The work reported herein draws on two sets of results independently achieved by Thresh, on the one hand, and by Crawley and White, on the other. EXPERIMENT The method and apparatus were originated by Thresh and have been described in detail in Mines Branch reports.172 In operation, the 14 cu cm graphite pycnometer is put in the furnace as shown in Fig. 1 after a machined charge has been placed inside the pycnometer and the lid screwed down. The dimensions of the charge are such that, upon melting, a small excess of liquid metal is discharged through the capillary hole to displace the weighted float above. When the pycnometer has been equilibrated at the experimental temperature, the

Jan 1, 1969

By S. Floreen

Seven iron alloys ranging from 5 to 12 pct Ni and 5 to 14 pct Cr were studied. All alloys transformed to bcc massive martensites. Tempering increased the strengths , probably because of relief of residual stresses generated by the martensite transformation. The major strengthening mechanism appeared to be solid-solution hardening by nickel and chromium. Studies of the work-hardening behaviw, of the effects of prior austenite grain size, and of the effects of changing strain rate and test temperature gaue results very similar to iron or low-alloy steels. Increasing nickel contents markedly improved the toughness at subzero temperatures. Studies of the flow properties did not, however, indicate the reason for the beneficial effect of nickel on toughness. The marine atmosphere corrosion resistance of the alloys was improved primarily by chromium additions, but increasing nickel contents were also beneficial at low levels of chromium. J\ number of maraging and PH stainless steels are strengthened by precipitation hardening in a low-carbon Fe-Ni-Cr martensite matrix. To some extent the resultant properties of these steels must depend upon the properties of this matrix. The present study therefore was conducted to evaluate the transformation characteristics and mechanical properties of a series of Fe-Ni-Cr martensitic ternary alloys. A limited evaluation of the corrosion resistance of the alloys in marine atmosphere was also made. ALLOY PREPARATION Seven 100-lb air induction melts were prepared using electrolytic iron, nickel, and chromium metal additions. The initial Fe-Ni charge also contained 0.05 wt pct graphite to produce a carbon boil during melt down. After melting of the base charge, the heats were refined with 0.1 wt pct additions of manganese, silicon, aluminum and titanium and poured into cast-iron molds. The ingots were homogenized at 1250°C and uni-directionally hot-rolled to 2-in. plate. They were then homogenized another hour at 1250°C, and unidirection-ally hot-rolled to %-in. plate at a finishing temperature of approximately 1050°C. The compositions of the heats are given in Table I. Two additional heats were prepared as 40-lb vacuum-induction melts using electrolytic iron, nickel, and chromium metals, and commercially pure molybdenum chips. A carbon boil, and 0.1 wt pct additions of aluminum and titanium were again employed, but manganese and silicon were not added. The heats were converted to %-in. plate using the procedure described above. The compositions of these heats are included in Table I.

Jan 1, 1967

By Michael B. Bever, Carl F. Floe

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By Carl F. Floe, Michael B. Bever

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By Joseph M. Jacisin

Fatigue tests were conducted on 2017-T4 alumium in alloy in an u1lrcthig.h vacuum of 2 x 10-lo Torr and in air. The vatio of vacuum-to-air faligue life for this ~malerial varied Jrom 3.5:1 at a strain of 2.5 X 1O-3 ill. pegr in. to 8:l at a strum of 3.3 x X ill. per 171. Sotlze pvelivtlinary data were also obtained on the faligue life of the alumirnum alloy in a dvy-nitrogen atmosphere. A dark deposit observed on the fracture surfaces of the aiv-tested specimens was identified as oxides of tr~angarzese and magnesium This observalion, and the close correlalion betaveen results obtained in vaCuum and dry-nitrogen environtments, tend to confirm that air stvongly influences the fatigue mechanism by a covrosion process. THE fatigue life of certain metals is known to increase when the atmospheric pressure is reduced. Gough and Sopwith1-2 postulated that this is due to a joint chemical and mechanical process operating in air at the surface of the metal with oxygen and water vapor playing significant roles. Wadsworth and Hutchings3 observed that aluminum is mainly affected by the presence of water vapor. Very little information is available on the fatigue properties of structural aluminum alloys in a vacuum environment. This report describes work performed on 2017-T4 aluminum alloy in an ultrahigh vacuum (2 x 10-loTorr) and in air. Some preliminary data are also presented on the fatigue life of the alloy in a dry-nitrogen environment. 1) EXPERIMENT 1.1) Test Material. The material tested was commerciaT 2017-T4 aluminum alloy which, in addition to aluminum, has an approximate composition of 4 pct Cu, 1 pct Fe, 0.8 pct Si, 0.5 pct Mg, 0.5 pct Mn, plus smaller amounts of other elements.* Some typical naturally age to a substantially stable condition. Specimens were then machined from these rods and ground to a No. 8 microfinish. In order to minimize variation in material characteristics, specimens were made from rods procured from the same lot. 1.2) Apparatus. The apparatus and test specimen used in the fatigue tests are shown in Fig. 1. The device utilized a single-cantilever beam with rotating-bending loading. Bending stress was applied to the fatigue test specimen by placing a spacer beneath the bearing support, thereby providing a constant deflec-

Jan 1, 1968

By D. L. Kelley

High-viscosity water injection has been proposed for use in reservoirs containing high-viscosity crude oils. Previous publications have largely ignored the possible effects of the connate water on the proposed process. This paper describes experimental work which indicates that the connate water will be forced ahead of the injected water to form a bank of low-viscosity water. This decreases the oil recovery which would be expected if such a bank were not formed. These effects are shown for a range of fluid mobilities and connate-water saturations for a five-spot injection system. In general, oil recoveries using viscous water are significantly greater than for untreated water even though they are less than would be expected if no connate water bank were formed. INTRODUCTION The effect of mobility ratio on the oil recovery of wa-terfloods has been known for many years. Muskat first pointed out that the fluid mobilities (k/µ) in the oil and water regions would affect the performance of the water-flood, and he estimated the general effect of these variables.' Since this early work, studies of the effect of mobility ratio on secondary recovery have been reported where mathematical,' potentiometric3 and scaled flow models' were used. These studies have shown that a reduction in the mobility ratio between the oil and the displacing fluid would cause additional oil recovery when water-flooding reservoirs containing viscous crude oils. Studies reported by Pye- nd Sandiford 8 have indicated that chemicals to increase injection water viscosity are now available and can be used to reduce the over-all mobility ratio of a waterflood. Where mobility ratios are controlled by the injection of viscous fluids, the connate water of the reservoir can play an important part in the displacement of the reservoir oil. The purpose of this study was to determine the effect of the connate-water saturation in waterfloods where viscous waters are used for injection. DISPLACEMENT OF THE CONNATE WATER Russell, Morgan and Muskat7 were the first to recognize the mobility of connate waters in waterflooding. They conducted waterfloods on oil-saturated cores containing 20 and 35 per cent irreducible water saturations, and found that from 80 to 90 per cent of the "irreducible" water was produced after only one pore volume of water was injected. However, their experiments were conducted at rates of flow significantly higher than those ordinarily occurring in waterfloods. Also, the cores were only from 4.0 to 8.5 cm long. Brown 4 studied a 100-cm linear sand pack which had been prepared to contain connate water and oil. He used 140- and 1.8-cp oils with injection water of essentially the same viscosity as the connate water. He found that all of the connate water was displaced by the injection water in both cases. However, the injection volumes required for complete displacement of the connate water were considerably higher in the case of the more viscous oil. To verify the results of the foregoing experiment, a 10-ft-long linear model was constructed by packing 250-300 mesh sand in a 1/2-in. diameter nylon tube. The model was evacuated, saturated with a brine of 1-cp viscosity, and flooded with a 41-cp mineral oil to the irreducible water saturation of 10.9 per cent. The model was then waterflooded by the injection of a water solution which had an apparent viscosity of 42.6 cp. The solution consisted of 0.5 per cent methylcellulose in distilled water. The viscosities of the oil and connate water were measured with an Ostwald viscosimeter. The viscosity of the polymer solution was calculated by Darcy's law using pressures measured during actual flow conditions. The ratio of the mobility in the oil region to the mobility in the inject ion-water region was approximately 0.32. The mobility ratio of the oil region to the connate-water bank was approximately 14. The mobility ratio between the connate-water bank and the injection water region was 0.024. Approximately 84.5 per cent of the recoverable oil was produced before water breakthrough. Immediately following breakthrough, oil and connate water were produced at an increasing water-oil ratio until the viscous injection water broke through. At viscous-water breakthrough, 96 per cent of the original connate water had been produced. After breakthrough of the viscous water, there was no additional production of connate water or oil. The near-

Jan 1, 1967

By J. O. Brittain, E. P. Lautenschlager, D. A. Kiewit

Compression tests were run in the temperature range of 700° to 900°C ox 0' phase NiAl intermetal-lic alloys of several grain sizes. At these temperatures the minimum strengths were observed at the stoichiometric composition. While significant increases in strength occurved in both the low-nickel (vacancy) and high-nickel (substitutional) regions, the highest strengths were found in the high-nickel region. During deformation serrated flow was sometimes observed in the low-nickel alloys. After deformation transgranular cvacking and deformation striations were observed in all compositions tested. AS part of a general investigation of the properties of NiAl inter metallic compounds, a preliminary study of the role of point defects upon plasticity was made by high-temperature compression tests on ß' NiAl specimens of several grain sizes and compositions. ß' NiAl is an intermetallic compound having a CsCl structure and a rather wide range of composition from A1-45 at. pct to 60 at. pct Ni.1 According to Bradley and Taylor2 and to cooper,' it possesses a defect lattice in which departures from stoichiometry in the direction of decreased nickel content lead to the presence of vacant nickel sites (although Cooper's work indicates that a small amount of substitution also occurs) whereas departures on the high-nickel side lead to substitution of nickel on aluminum sites. NiAl forms congru-ently from the melt at approximately 1650°C,1 and thus has a higher melting point than either of its component elements. Up to this time, although this and other high-melting intermetallic compounds have been suggested for elevated-temperature usage,4 only the hardness4 and a few tensile-strength measurements5 have been reported for NiAl at high temperatures. In the present investigation the effects of composition upon the compressive-strength properties in a range of 700° to 900°C have been measured for NiAl of several grain sizes. EXPERIMENTAL PROCEDURES The alloys were made as described elsewhere6 from an A1-46.8 at. pct Ni master alloy furnished by the International Nickel Co. with additions of high-purity nickel and aluminum. The charges were vacuum-induction-melted in A12O3 crucibles with small amounts of helium added to the atmosphere to suppress vaporization. They were cooled slowly from the melting temperature to achieve uniform grain size. In order to refine the as-grown grain size a special rolling technique was developed. Alloys were packed into 0.10-in. wall-type 302 stainless-steel tubes which were partially filled with magnesium oxide to prevent bonding between the alloy and the steel jacket. The ends of the tubes were closed by hot forging, and the packets were then hot-rolled. The alloys with greater than 50 at. pct Ni were rolled at 1100°C, but it was found necessary to increase the temperature to 1350° C before alloys with less than 50 at. pct Ni would roll without cracking. With these temperatures, reductions as high as 48 pct were achieved in a single pass. The rolled alloys will hereafter be referred to as "fine grained" whereas the as-grown material will be designated "coarse-grained''. The compression specimens were made by cutting square cross-sectional pieces, approximately 3/16 by 3/16 by 1/2 in., with a water-cooled diamond cut-off wheel from the as-grown or the rolled alloys. Specimens were ground to their final dimensions by polishing through 3/0 grit silicon carbide papers. The final shape was a rectangular parallelepiped of square cross section having a height-to-width ratio of 3:1. Compression testing was carried out in a compression rig of our own design mounted on an In-stron Floor Model. The specimen chamber could be heated to 1000°C and was controlled within ±2°C. The compression rig was enclosed within a bell jar and was maintained at a 50 µ of mercury vacuum throughout the duration of the test. The test cham -ber was heated from room to test temperature within 15 min. Specimens were then held at the test temperature 30 min prior to testing. Previous experiments indicated that no grain growth would occur within this time. An Instron Variable Crosshead speed unit was used to adjust for small variations in specimen lengths in order to have a constant initial strain rate, €, for all specimens of a group. For the fine-grained specimens the strain rate was changed rapidly at constant temperature by a factor of 10 with the speed lever on the Instron. For a given € the compression data was analyzed in terms of true plastic strain (E) and true compressive stress (0).

Jan 1, 1965

By J. T. Williams

The equilibria in the V-Zr alloy system were investigated by solidus temperature determinations, thermal analysis, dilatometry, electrical resistance measurements, microscopic examination, and X-ray diffraction analysis. There is a eutectic reaction at 1230°C between a compound, V2Zr, and a solid solution containing 10 pct V in ß zirconium. V2Zr decomposes at 1300°C into liquid and a solid solution containing about 10 pct Zr in vanadium. The eutectic composition is probably about 30 pct V. A eutectoid reaction between V2 Zr and a zirconium takes place at 777°C at a very high rate. The eutectoid composition is 5 wt pct V. The limit of solubility of zirconium in vanadium was estimated to be 5 pct at 600°C. No attempt was made to determine the liquidus for the system. THE recent availability of large quantities of high purity zirconium has stimulated the study of zirconium binary systems. The equilibrium diagram for the V-Zr system has received little attention, however. Wallbauml appears to have made the first report concerning the equilibria in these alloys. He reported the existence of a compound, V2Zr, having the MgZn2 ((214) type of structure with a, = 5.277 kX and c° = 8.647 kX. Anderson, Hayes, Roberson, and Kroll2 made a survey of some potentially useful zirconium binary alloys and found that zirconium probably dissolves a small amount of vanadium. They reported the probable existence of a compound between the two elements and suggested that the zirconium-rich solid solution undergoes a eutectic reaction with this compound. Pfeil," in a critical review of the existing information, estimated that the solubility of vanadium in zirconium is less than 4.7 pct and probably less than 1.8 pct. Rostoker and Yamamoto' proposed a partial diagram for the V-Zr system in a survey paper on vanadium binary alloys. Their diagram indicates the compound, V,Zr, a eutectic reaction at 1360°C, a peritectic reaction at 1740°C, and a limit of solubility of zirconium in vanadium of about 3 pct. They obtained no information on the equilibria in the zirconium-rich alloys. In view of the potential utility of the V-Zr alloys and the incomplete knowledge concerning the equilibria in the system, an attempt was made to establish the constitutional diagram. Preparation of the Alloys Raw Materials: The vanadium for making up these alloys came from the Electro Metallurgical Corp. Zirconium came from two sources. In the beginning of the investigation, sponge zirconium from the Bureau of Mines was used in making some of the alloys. Later, iodide metal made at the Westinghouse Atomic Power Development Laboratories became available. This material was used in the preparation of all the dilatometric and resistance specimens and about two-thirds of the solidus temperature specimens. A typical manufacturer's analysis of the vanadium is shown in Table I. No other analysis of the vanadium was made. The metal contained a dispersed second phase and did not have a sharp melting point. Typical results of spectrographic analysis of the Westinghouse zirconium are shown in Table 11. These data indicate a very high purity. The Bureau of Mines sponge metal was probably less pure but had good ductility. Melting: All of the alloys used in the investigation were made by melting pieces of vanadium and zirconium together in a dc electric arc furnace similar to those of Geach and Summers-Smith, craighead, Simmons, and Eastwood," and others. Melting was done in an atmosphere of helium scavenged of residual air by the preliminary melting of a separate charge of zirconium. Each ingot was turned over and melted at least three more times before removal from the furnace to aid in the attainment of homogeneity. Alloys prepared for use in the investigation are listed with the results of solidus determinations in Table III with the exception of the following compositions upon which no solidus determinations were made: 0.29, 0.54, 4.57, and 5.55 pct V. Analysis: The weight of each ingot made from iodide zirconium was within 0.1 g of the total weight of the initial charge, about 90 g. Since each component of each charge was weighed to the nearest 20 mg for amounts less than 10 g and to the nearest 0.1 g otherwise, the gross composition of an ingot could be calculated accurately. Chemical analysis for the vanadium content of several alloys agreed

Jan 1, 1956

By H. R. Cooper, T. S. Mika

T. S. Mika (Department of Mineral Technology, University of California, Berkeley, Calif.) - Dr. Cooper's attempt to establish a correlation between process behavior and operational variables on the basis of a statistical analysis after imposing a reasonable process model is a very commendable improvement on the use of standard regression techniques. However, it must be recognized that the imposition of a model has the potential of yielding a poorer representation if its basic assumptions or mathematical formulation are invalid. It appears that at least two aspects of his treatment require some comment. First, the limitations on the kinetic law where xta represents a hypothetical terminal floatable solids concentration (cf. Bushell1), should be mentioned. Most current investigations2-9 appear to utilize the concept of a distribution of rate constants rather than a single unique value, k, to describe flotation kinetics. A distributed rate constant is certainly a more physically meaningful concept than that of a terminal concentration. The study of Jowett and safvi10 strongly indicates that xta is merely an empirical parameter, whose actual behavior does not correspond to that expected from a true terminal concentration. Rather than being a strictly mineralogical variable, as Dr. Cooper's treatment implies, it apparently represents the hydromechanical nature of the test cell as well as the flotation chemistry. The extension of batch cell kinetic results to full-scale continuous cell operation is a suspect procedure if the effect of such nonmineralogical influences on x,, remain unevaluated. There is evidence that introduction of a terminal concentration is necessitated by the inherent errors which arise in batch testing and are eliminated by continuous testing methods.' Possible lack of validity of the author's use of Eq. 1 is indicated by two unexpected results of the statistical analysis of his batch data. The first is the apparent corroboration of the assumption that the rate constant, k, is independent of particle size, i.e., of changes in the size distribution of floatable material. This assumption directly contradicts numerous results 2,4,11-l8 for cases where first order kinetics prevailed and ignores the phenomenological basis for the analysis of flotation in terms of a distribution of k's. It must be recognized that, if the rate constant is size dependent, the lumped over-all k would be time dependent; Eq. 1 would then no longer be valid. Cooper's x,, is determined by batch flotation of a distribution of sizes for an arbitrary period of time. If the size dependence of k is artificially suppressed, x,, will become a function of the experimental flotation time used in its determination. Upon reviewing the rather extensive literature concerning batch flotation kinetics, there appear to be few instances where constant k and x,, adequately adsorb variations in floatability due to particle size. The second surprising result is the low values of the distribution modulus, n, determined. Contrary to Cooper's assertion, most batch grinding (ball or rod mill) products yield values of n > 0.6, which increase as the material becomes harder.'' It is likely that the values of n = 0.25 and n = 0.42 for Trials 1 and 2, respectively, are completely unreasonable, and even the value n = 0.54 obtained for Trial 3 is unexpectedly low. Possibly, this indicates inherent flaws in the three trial models considered, in particular the assumed particle size independence of the rate constant, k. The above does not necessitate that Eq. 1 (and the terminal concentration concept) is invalid; it could constitute a good first approximation. However, the qualitative arguments used by Dr. Cooper in its justification are somewhat frail and require verification, particularly since much of the flotation kinetics literature is in opposition. Apparently, no effort was made to test these hypotheses on the actual data; in fact, since they pertain to a single batch test time, his data cannot be utilized to evaluate the kinetics of flotation. To evolve a control algorithm on the basis of this infirm foundation seems a questionable procedure. Another difficulty in his analysis arises in consideration of the froth concentrating process. As Bushel1 ' notes, for Eq. 1 to be valid it is necessary that the rate of recycle from the froth be directly proportional (independent of particle size) to the rate of flotation transport from the pulp to the froth, a restrictive condition." Harris suggests that it is more realistic to assume that depletion occurs in proportion to the amount of floatable material in the pertinent froth phase volume (treating that volume as perfectly mixed).12,21,22 The physical implications of

Jan 1, 1968

By C. A. Stetefeldt

In May and June, 1885, I was engaged in examining the goldores of Las Minas, in the State of Vera Cruz, Mexico, with a view of finding a cheap and efficient method for extracting the gold. The following minerals could be plainly seen in the ore : magnetite, pyrites of iron, pyrites of' copper, quartz, and garnet. Neither galena nor zinc-hlende mere visible, but the ore contained a trace of lead, and in some samples of ore from the Muertos mine, 1.19 per cent. of zinc mas found. Antimony and arsenic were not present. Native gold could scarcely be seen in specimens of' the ore, and it only appeared—mainly in extremely fine particles—after pulverizing and washing. Magnetite was in every instance the most prominent mineral, its quantity varying between 43 and 67 per cent. Determinations of copper and sulphur showed that from 3.5 to 7 per cent. pyrites of copper, and from 3 to 22 per cent. pyrites of iron were present. The gold-value of the ore varied between 0.3 oz. and 0.8 oz. per ton. I do not speak of specimens, but of average samples of large quantities of ore put through the battery. In ore that had been crushed through a No. 40 screen, the gold appeared, in part, as free gold, the rest being thoroughly mixed with the magnetite and pyrites, both minerals containing about the same percentage of gold. If this free gold was brought in contact with pure quicksilver it (lid not amalgamate readily, even if the quicksilver was charged with sodium amalgam.

Jan 1, 1886

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey's past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.' These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935

By L. F. Reinartz

The furnace in which rimming steel is made has an important bearing on the quality of the steel produced. Furnace.—Particularly in the manufacture of low-carbon rimming steels, it is necessary to have an efficient, easily regulated furnace, because of the relatively high finishing temperature requirements. In recent years, the most important development in design of open-hearth furnaces has been the sealing and insulation of the greater part of the furnace to prevent air infiltration and loss of heat. Efficient, straight-line valves insure proper draft. Combustion controls guarantee correct gas-air ratios. Furnaces of all sizes ranging from 20 to 200 tons have been used successfully in the manufacture of rimming steels. Metal bath is varied from 20 to 40 in. in depth without appreciable variation in quality. Charging.—A normal open-hearth charge consists of pig iron (hot or cold), scrap of miscellaneous nature, and slag-making additions, such as limestone and burnt lime. Because of local conditions, some plants find it necessary to discard the use of pig iron and use some carbonaceolis substances with varying percentages of cast iron to replace the pig iron. It is questionable whether such practice will consistently produce the quality of rimming steel required for auto stampings and other severe drawing requirements. Pig Iron.—An open-hearth furnace under proper control should melt 150 tons of low-carbon rimming steel on about 35 to 38 per cent pig-iron charge basis. In some practices, best results are obtained when the total charge contains from 0.40 to' 0.50 per cent silicon. If reasonably low-

Jan 1, 1935

By L. F. Reinartz

The furnace in which rimming steel is made has an important bearing on the quality of the steel produced. Furnace.—Particularly in the manufacture of low-carbon rimming steels, it is necessary to have an efficient, easily regulated furnace, because of the relatively high finishing temperature requirements. In recent years, the most important development in design of open-hearth furnaces has been the sealing and insulation of the greater part of the furnace to prevent air infiltration and loss of heat. Efficient, straight-line valves insure proper draft. Combustion controls guarantee correct gas-air ratios. Furnaces of all sizes ranging from 20 to 200 tons have been used successfully in the manufacture of rimming steels. Metal bath is varied from 20 to 40 in. in depth without appreciable variation in quality. Charging.—A normal open-hearth charge consists of pig iron (hot or cold), scrap of miscellaneous nature, and slag-making additions, such as limestone and burnt lime. Because of local conditions, some plants find it necessary to discard the use of pig iron and use some carbonaceolis substances with varying percentages of cast iron to replace the pig iron. It is questionable whether such practice will consistently produce the quality of rimming steel required for auto stampings and other severe drawing requirements. Pig Iron.—An open-hearth furnace under proper control should melt 150 tons of low-carbon rimming steel on about 35 to 38 per cent pig-iron charge basis. In some practices, best results are obtained when the total charge contains from 0.40 to' 0.50 per cent silicon. If reasonably low-

Jan 1, 1935