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By W. I. Duvall

A brief review of the resonant frequency and ultrasonic pulse methods for obtaining elastic constants of rock samples shows that the equations for an iso-tropic elastic solid commonly used to calculate Young's modulus, modulus of rigidity and Poisson's ratio can result in appreciable error if the rock is even slightly anisotropic. Consideration of the equations that relate bar velocities and free medium velocities to elastic constants for orthotropic, transversely isotropic and isotropic solids shows that a combination of the two methods can be used to determine average elastic constants for a single sample of rock. The determination of elastic constants in different directions requires a large number of tests on oriented samples. The use of both the resonant frequency and ultrasonic pulse methods is recommended so that the determination of both Young's modulus and modulus of rigidity is independent of the determination of Poisson's ratio. The dynamic elastic constants of rock can be determined in the laboratory from measurements on small samples which may be in the form of right circular cylinders (diamond drill core). Either the resonant frequency6 or ultrasonic pulse method1 can be used to determine the longitudinal and shear velocities in the same specimen. The resonant frequency method provides a measure of the longitudinal bar velocity, V,, and the torsional bar velocity Vt; whereas the ultrasonic pulse method provides a measure of the free medium longitudinal velocity, Vp, and the free medium shear velocity, V, . The elastic constants (Young's modulus E, modulus of rigidity G, and Poisson's ratio v) are calculated from the density of the specimen, p, and one of the pairs of velocities by means of equations from isotropic elastic theory. For the resonant frequency method the equations are: It should be noted that Eq. 5 is derived from Eq. 4 and 6 and the relation between the elastic constants for an isotropic solid as given by the first part of Eq. 3. The in situ determination of dynamic elastic constants is accomplished by generating a complex seismic pulse in the rock and measuring the arrival times for the longitudinal and shear phases of the pulse at two distant points.5 From these travel times and the distance of the travel path both Vp and Vs are determined. The density of the rock is determined from samples in the laboratory, and Eq. 4 to 6 are used to calculate the elastic constants. These three methods involve the assumption of isotropy and perfect elasticity, and require the use of the relation v = (E/2G) - 1, which holds only if the elastic constants are the same in at least two directions. The calculation of v by means of Eq. 3 introduces considerable error, as a 1% error in V, and V, results in a 20% error in v. If frequencies for samples with a length-to-diameter ratio greater than four and a length greater than 8 in. are measured carefully, the experimental error can be kept to 1%. However, it is not unreasonable to expect that the variation in Vb and Vt with direction may exceed 1%. Thus, for even a small percentage of anisotropy the use of Eq. 3 can result in considerable error in v. The calculation of v by Eq. 5 also involves some uncertainty as a 1% error in Vs and Vp can result in a 6% error in v. By means of the pulse method both

Jan 1, 1965

By K. S. Gritton

The U.S. Bureau of Mines has investigated methods for extracting metals from a variety of arsenic-containing smelter flue dusts. One proposed flowsheet includes a sulfuric acid leach, a cooling step to precipitate hydrated copper sulfate, and a reduction-precipitation of As2O3. Arsenic extractions greater than 90 pct were achieved, while copper extraction ranged from 50 to 85 pct under the conditions examined. Copper was removed from the leach solutions by crystallization followed by SO2 precipitation of arsenic which resulted in a 98 to 99.9 pct As2O3 product. Other metals, such as lead and zinc, were concentrated in the leach residue or in other byproduct streams for recovery of their valuable metal contents.

Jan 1, 1990

By Victor Formanek, Paul Chataignon, Maurice Rey

IT is found when floating oxidized lead ores by sulphidization, that the presence of calcium salts in the water, is usually detrimental and lowers the recovery. This effect is particularly marked in dry countries such as North Africa, where the waters often carry large amounts of calcium sulphate and where the ore may even contain gypsum. The effect of calcium salts is readily visible. Whereas in their absence cerussite is quickly stained brown and then black by sodium sulphide, in their presence the mineral remains very light in color. A similar effect is produced when barium sulphide is used as a sulphidizing agent instead of sodium sulphide. Magnesium salts have little or no effect and even tend to reduce the detrimental effect of calcium salts. A study of this phenomenon indicates that it is due to the precipitation of calcium or barium carbonate in contact with the mineral simultaneously with the formation of lead sulphide. The chemical reactions can be interpreted as: PbCO3 + Na2S = PbS + Na2CO3 CaSO4 + Na2CO3 = CaCO3 + Na2 SO4 They might also be written: PbCO3 + S = + Ca++ = PbS + CaCO3 The precipitation of calcium carbonate can be followed by the lowering of the pH with which it is accompanied. Magnesium carbonate is more soluble than calcium carbonate and usually does not precipitate under the conditions prevailing. It is interesting to note that calcium salts have no effect on anglesite (lead sulphate) because calcium sulphate is soluble, but barium salts hinder the sulphidization of anglesite because of the precipitation of barium sulphate. Remedies When calcium sulphate is present in large amounts, the softening of the water with soda ash is usually too expensive to be considered, but the precipitation of the objectionable calcium carbonate can be prevented in two different ways. One is the use of sodium hydrosulphide instead of sodium sulphide. This salt gives a lower pH than sodium sulphide and does not bring about the immediate precipitation of the calcium which remains in solution as calcium bicarbonate. The other procedure is to add ammonium salts such as the sulphate or chloride which have the property of increasing markedly the solubility of calcium carbonate. Ammonium salts have other effects such as cutting down conditioning time and accelerating flotation. They should be added to the flotation cells rather than to the ball mills. Table I. Effect of Sodium Hydrosulphide and/or Ammonium Sulphate on the Flotation of Two Oxidized Lead Ores Mibladen Ore4 La Plagne Ored Con- Tall- Con- Tail-centrate ing centrate ing Reagents Pb, Pct Pb, Pct Pb, Pct Pb, Pot Without addition of CaSO, NaS 56.0 0.68 43.4 0.65 NaSH 56.2 0.60 40.4 0.50 Na2S + (NH4)2SO4d 54.6 0.56 NaSH + (NH4)2SO4d 43.0 0.66 With addition of 40 lb/ton CaSO4 Na2S 39.4 3.85 34.0 3.21 NaSH 49.1 0.70 49.6 0.88 Na2S + (NH4)2SO4d 53.9 0.85 NaSH + (NH4)2SO4d 51.0 0.45 41.1 0.78 In table I are given the results of representative tests on two different oxidized ores. They show that the strongly detrimental effects of calcium sulphate can be offset by the two procedures outlined above. Sodium hydrosulphide is now used regularly on a mill scale on certain ores. Tests are being carried out with ammonium salts. It should be noted that malachite is subject to influences similar to cerussite. One final word of caution—when the ore is rich in primary slime, which is flocculated by the calcium salts, it may be indispensable to remove these by washing or precipitation with sodium carbonate instead of keeping them in solution by the above methods. Acknowledgment We wish to thank Socibtk Miniere & Metallurgique de Penarroya and Minerais et Metaux, for permission to publish these results.

Jan 1, 1951

By Maurice Rey, Victor Formanek, Paul Chataignon

IT is found when floating oxidized lead ores by sulphidization, that the presence of calcium salts in the water, is usually detrimental and lowers the recovery. This effect is particularly marked in dry countries such as North Africa, where the waters often carry large amounts of calcium sulphate and where the ore may even contain gypsum. The effect of calcium salts is readily visible. Whereas in their absence cerussite is quickly stained brown and then black by sodium sulphide, in their presence the mineral remains very light in color. A similar effect is produced when barium sulphide is used as a sulphidizing agent instead of sodium sulphide. Magnesium salts have little or no effect and even tend to reduce the detrimental effect of calcium salts. A study of this phenomenon indicates that it is due to the precipitation of calcium or barium carbonate in contact with the mineral simultaneously with the formation of lead sulphide. The chemical reactions can be interpreted as: PbCO3 + Na2S = PbS + Na2CO3 CaSO4 + Na2CO3 = CaCO3 + Na2 SO4 They might also be written: PbCO3 + S = + Ca++ = PbS + CaCO3 The precipitation of calcium carbonate can be followed by the lowering of the pH with which it is accompanied. Magnesium carbonate is more soluble than calcium carbonate and usually does not precipitate under the conditions prevailing. It is interesting to note that calcium salts have no effect on anglesite (lead sulphate) because calcium sulphate is soluble, but barium salts hinder the sulphidization of anglesite because of the precipitation of barium sulphate. Remedies When calcium sulphate is present in large amounts, the softening of the water with soda ash is usually too expensive to be considered, but the precipitation of the objectionable calcium carbonate can be prevented in two different ways. One is the use of sodium hydrosulphide instead of sodium sulphide. This salt gives a lower pH than sodium sulphide and does not bring about the immediate precipitation of the calcium which remains in solution as calcium bicarbonate. The other procedure is to add ammonium salts such as the sulphate or chloride which have the property of increasing markedly the solubility of calcium carbonate. Ammonium salts have other effects such as cutting down conditioning time and accelerating flotation. They should be added to the flotation cells rather than to the ball mills. Table I. Effect of Sodium Hydrosulphide and/or Ammonium Sulphate on the Flotation of Two Oxidized Lead Ores Mibladen Ore4 La Plagne Ored Con- Tall- Con- Tail-centrate ing centrate ing Reagents Pb, Pct Pb, Pct Pb, Pct Pb, Pot Without addition of CaSO, NaS 56.0 0.68 43.4 0.65 NaSH 56.2 0.60 40.4 0.50 Na2S + (NH4)2SO4d 54.6 0.56 NaSH + (NH4)2SO4d 43.0 0.66 With addition of 40 lb/ton CaSO4 Na2S 39.4 3.85 34.0 3.21 NaSH 49.1 0.70 49.6 0.88 Na2S + (NH4)2SO4d 53.9 0.85 NaSH + (NH4)2SO4d 51.0 0.45 41.1 0.78 In table I are given the results of representative tests on two different oxidized ores. They show that the strongly detrimental effects of calcium sulphate can be offset by the two procedures outlined above. Sodium hydrosulphide is now used regularly on a mill scale on certain ores. Tests are being carried out with ammonium salts. It should be noted that malachite is subject to influences similar to cerussite. One final word of caution—when the ore is rich in primary slime, which is flocculated by the calcium salts, it may be indispensable to remove these by washing or precipitation with sodium carbonate instead of keeping them in solution by the above methods. Acknowledgment We wish to thank Socibtk Miniere & Metallurgique de Penarroya and Minerais et Metaux, for permission to publish these results.

Jan 1, 1951

By N. Choi, W. D. Cho

Distribution coefficients of gold and silver between matte and slag during the pyrometallurgical treatment of nickel-copper sulfide concentrates were evaluated as a function of matte and slag compositions in the temperature range of 1,250oC to 1,300oC. It was observed that the composition of the matte phase, including matte grade and copper content in the matte, significantly affected the distribution behavior of gold and silver in the matte-slag system. Both gold and silver preferentially concentrated in the matte phase as the matte grade increased With increasing temperature and copper content in the matte, the distribution coefficients of silver increased, while the gold distribution coefficients decreased. It was also, found that slag additives such as CaO, MgO, and A12O3 caused a significant decrease in the solubility of both gold and silver in silica-saturated iron silicate slag. An activity coefficient of gold in matte was derived from the experimenta1 results.

Jan 1, 1999

By E. F. Bailey, W. J. Harris

THE temperature of the ferrite to austenite re-action is established frequently by continuous heating experiments. However, equilibrium studies of this reaction have demonstrated that austenite may form at temperatures considerably below those at which the reaction is first observed during continuous heating. Because of this discrepancy, tempering is sometimes performed above the true critical temperature and in these cases austenite forms during tempering. The lowest temperature at which austenite forms and the kinetics of the reaction have been studied by Bain,' Bleakney and Gros-venor,2 and Dube and Cunningham. This austenite can affect the properties either as austenite per se, if it is retained at room temperature, or as a decomposition product if it transforms. The effect of austenite formation during tempering on low temperature impact properties of an 8 1/2 pct nickel steel was reported by Brophy and Miller4 in work published after the present investigation was initiated. They concluded that the improvement in low-temperature notch toughness which followed tempering at certain temperatures could be attributed to the austenite formed during tempering. Kramer et al.5 found anomalous hardness increases and embrittlement after tempering of a low-carbon manganese-nickel steel. They concluded that austenite formed during tempering, and that the decomposition products were responsible for the increase in hardness and the embrittlement. Quan-titative correlations of the microconstituents and mechanical properties were not made by these investigators. The present study was undertaken in order to establish the kinetics of formation of austenite at various temperatures, the characteristics of the decomposition of this austenite, and the relationship between mechanical properties and the phases present. Experimental Procedure A low-carbon manganese-nickel steel was selected because of the sluggishness of its austenite decom-position reactions. The composition of this steel in percent was: C, 0.10; Mn, 3.52; Ni, 2.34; Mo, 0.52; Cr, 0.17; Si, 0.19; V, 0.15; P, 0.019; and S, 0.020. Samples were prepared by forging sections from a large ingot to 3/4 in. bars. Formation and decomposition of austenite were investigated by dilatometric techniques which were checked by X-ray measurements. Dilatometer specimens were hollow cylinders 1 in. long, 1/2 in. diam, with a 1/8 in. central hole. All specimens were aus-tenitized for 1 hr at 1650°F and quenched in water prior to insertion in the dilatometer. Oxidation was prevented by using an inert atmosphere of purified nitrogen. Dilation was measured with a dial gauge which could be read by interpolation to 0.00005 in. Temperature was maintained within ± 3°F by a Brown Electronik Controller. Chromel-alumel thermocouple leads were welded to opposite ends of the specimen with the specimen serving as the hot junction. As a check on temperature uniformity comparison was made of the specimen temperature as measured with the chromel-alumel leads and the temperature of the center of the specimen as measured with a calibrated platinum—platinum-rhodium thermocouple embedded in asbestos in the central hole of the specimen. During heating a 5°F temperature difference was noted below 1000°F, but none above, while in cooling, a 5°F difference was observed from 1300" to 735°F, but none below. Heating rates of 35°F per min and cooling rates of 60°F per min were employed for all dilatometric studies. For transformation studies below room temperature, the dilatometer was allowed to cool to 150°F and then was quenched into liquid nitrogen.

Jan 1, 1951

By Harold W. Lipper

HELIUM shipments in 1963 exceeded the volume shipped during the previous year for the 14th successive time. Shipments from Bureau of Mines plants were 627.3 million cubic feet, an increase of 5 percent over the volume shipped in 1962. Production from Bureau of Mines plants totaled 774.2 million cubic feet. The Bureau purchased 1,420 million cubic feet of helium in the helium conservation program and stored it underground for future use. Each of the five plants, financed and built by private industry for helium conservation, made deliveries during the year. Helium continued to playa key role in space, atomic energy, defense, and other research programs. Additional capacity for liquefying helium became available, and the first civilian helium-cooled nuclear-powered reactor in the United States began pre-operation testing.

Jan 1, 1964

By Hui Zhang, Fei Yang, Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"For a copper-sulfur polymetallic mine in south China, the main valuable minerals were chalcopyrite, pyrite and pyrrhotite. The flotability of pyrrhotite was similar with chalcopyrite and pyrite and it was easy to be oxidized. As a result, the indexes of copper concentrate and sulfur concentrate were unsatisfactory. Furthermore, the recycling of tailings water ulteriorly deteriorated the technical indexes of copper-sulfur ore beneficiation. After a large amount of experimental studies, under the condition that the tailings water recycling rate was 100%, the copper concentrate with a grade of 22.25%Cu and a recovery of 82.46% on average was obtained for the raw ore containing 0.517%Cu, 15.94%S, 25.46%Fe on average, through using new technology “magnetic separation-flotation” and effective adjustment of parameters in the industrial test which was continuously conducted for 14 shifts in 5 days with a scale of about 75t/d. Comparing with the production indexes (the copper concentrate with a grade of 17.49%Cu, the recovery was 62.27%) during the corresponding period, the grade of copper concentrate increased 4.76%Cu, and the recovery increased 20 percentage points. Besides, the indexes of sulfur concentrate gained a considerable improvement. Currently, the new technology was adopted in the design of the new-built plant with a scale of 7000t/d of this mine. The new technology provided powerful support for the tailings water recycling and indexes improvement of copper-sulfur ore beneficiation.INTRODUCTION Chalcopyrite was usually associated with pyrite and pyrrhotite in copper-sulfur ore. Due to the similar flotability, it was difficult to obtain copper concentrate and sulfur concentrate with high grade. Furthermore, sulfide ore was easy to be oxidized and a large amount of ions formed in the pulp by the dissolution of minerals, which made the pulp become acidic. As a result, pyrite and pyrrhotite were easy to be activated in acidic solution and their flotabilities became stronger. Meanwhile, hydrophilic film formed on the surface of chalcopyrite in raw ore. The flotability of chalcopyrite became weaker and it made the separation of chalcopyrite from pyrite and pyrrhotite more difficult. So it was more difficult for copper and sulfur recovering with the recycling of tailings water containing high content of heavy metal ions and reagents."

Jan 1, 2018

By Paul B. Warrington

This paper presents a discussion of the factors affecting copper scrap markets, including such items as price levels, freight. grades of material, sources and packaging. Reference will also be made to the effective life and turn-around of the copper content of some products. Introduction IN TERMS OF SIZE, copper scrap is second only to ferrous scrap in tonnage recycled. However, in total value, it is second to none. For example, world scrap recovery during the preceding 4 years averaged just under 2,300,000 metric tons per annum, and at an average price of 70 ¢ a pound, this works out at a turnover of about $3.5 billion, which indicates that the copper scrap industry, or recycling as it is now becoming known , is a substantial one.

Jan 1, 1977

By Yuanbo Zhang, Zhixiong You, Zijian Su, Bingbing Liu, Guanghui Li, Guang Yang, Tao Jiang

Sodium stannate is widely used in the electroplating and tin alloy industry. But the traditional processes for sodium stannate production are characterized by long flowsheet, high production cost and strict requirement for the equipments, etc. In this study, a novel process for sodium stannate preparation from cassiterite concentrate and sodium carbonate via roasting in CO/CO2 mixed gas then followed by leaching was developed. The effects of roasting parameters on the Sn leaching efficiency were conducted. A Sn leaching efficiency of 77.2% was obtained under the optimal conditions. Sodium stannate (Na2SnO3·3H2O) with a purity of 95.8% was produced by the new process, which is better than that specified for the industrial first-grade product.

Jan 1, 2014

By D. J. Bauer

The Bureau of Mines has conducted extensive studies on the recovery of alumina from kaolinitic clay by a HCI leaching-HCI sparging process. The current study reports a modification of the process, which involves a double-leaching system. The first leach of the calcined clay is made at as high a HCI acid strength as possible so that the dissolution of aluminum chloride hexahydrate (AlCI3*6H20) is suppressed, Most of the impurities, but very little aluminum, are soluble in the strong acid. After liquid-solid separation and washing, the solids are leached with recycled weak HCI, which dissolves the AICI3'6H2O. The pregnant liquor is separated from the gangue, and AICI3'6H2O is crystallized from solu-tion by injecting HCI gas. A proposed flowsheet is presented, and the effect of bleedstream size on AlC13'6H20 purity is discussed.

Jan 1, 1984

By John R. Bogert

The title of this session is "Wall Street Looks at the Mining Industry," and I am going to attempt to answer the question: Shouldn't Mining Stocks Sell at Higher Price Levels? Or, What Does Wall Street See When Looking at the Mining Industry? Well, it sees a capital intensive business, a technical industry, and a growing industry becoming more vertically integrated. But, at the same time, Wall Street sees a cyclical industry, a fragmented industry of erratic earnings, spotty public relations, a feast-or-famine business where the public usually does not differentiate between coal mining or metal mining, and does not appreciate either the risks or the rewards. As a result, mining stocks generally sell at relatively low price learnings ratios in comparison to other industrial groups. This PIE ratio, the current market price of the capital stock divided by annual earnings per share, is probably the most popular index of a stock's value. The average of the price/ earnings ratios of the 30 stocks comprising the Dow Jones Industrial Average is over 14. This diverse group of stocks is widely regarded as being a cross-section and representative of the industrial companies listed on the New York Stock Exchange. However, in comparison to 14, Asarco and Kennecott shares are currently available for about 8 times annual earnings. Even discounting earnings from South America, the stock of these two companies sells at only 10 times earnings. Of course, Peruvian politics is currently preventing Cerro shares from selling above 6 times earnings, and Chilean politics keeps Anaconda shares at a PIE multiple of 7. However, even in better times, these companies rarely sell above 10 times earnings. American Metal Climax and Newmont sell at only 11 times earnings as does Phelps Dodge and St. Joseph Lead. Few mining companies then have what can be considered a high PIE ratio-a figure higher than

Jan 1, 1970

By F. Valton

In the number of the Engineering and Mining Journal for April 7th, 1877, Mr. W. P. Ward, of Cartersville, Georgia, explains in a very interesting manner, the results he obtained in the manufacture of ferromanganese in the blast furnace. These results may be summed up as follows : Production in the blast furnace of an alloy containing 67.2 per cent. manganese and 3 per cent. of carbon at most, with a utilization of the manganese amounting to 58 per cent. With the exception of the indicated proportion of' carbon, which should be almost doubled to express the true state of facts, we would have had no observations to make on Mr. Ward's paper had he taken into account the results obtained in the same line in other centres of production. Before 1870, spiegel with 8 or 10 per cent. manganese only was known among blast-furnace products. In a journey to Sweden, in 1871,I ascertained that the Schysshyttan works manufactured regolarly a spiegel with 18 per cent. manganese. Later, at the Vienna Exhibition, in 1873, the Sava and Jauerburg works, in Carniola, presented to the jury a ferromanganese, obtained in the blast fur-

Jan 1, 1879

By R. L. Morse

The thermodynamic program is similar to previous mine ventilation programs but has been expanded to consider the compressibility of air. The thermodynamic program does consider: 1) air density variations, 2) humidity changes, 3) intake, exhaust, and underground fans, 4) heat transfer between rock and air, 5) refrigeration of heating plants, both surface and underground, and 6) heat generated by equipment, both diesel and electric. 110st of the compressibility factors are handled in the branch calculations. The field survey necessary to supply-data for this program is quite similar to the basic base and leap-frog pair of stations method used with most incompressible mine ventilation programs. The thermodynamic program is a complete package of ventilation network analysis which can provide mine management with good operational control and planning of mine ventilation systems.

Jan 1, 1977

By Michael Beyer

Following the last Cholera Epidemic in 1872, resulting in approximately 400 deaths, the City Council of Munich decided to re¬place the former water supply system within the city limits by tapping new water supply areas outside of the city. Since 1883 Munich has been obtaining its water from the Mangfall River catchment located some 35 km to the south. Its most distinguishing characte¬ristics are as follows: 1) the water is free-flowing, i.e., a pumping system is not required as the catchment area is 100 m higher than the city; 2) the water does not normally have to be treated, meaning "spring fresh" tap water. On a daily basis, 300,000 m3 of water flow through the more than 100 year old pipes, accounting for 70% of the city's daily need. There was originally no requirement of a water tight system as strategically installed drain pipes prevented the build-up of exter¬nal water pressure on the lining. As the qua¬lity of today's water has become significant¬ly worse, the tunnels are now in dire need of restoration or replacement.

Jan 1, 1995

By John F. Abel

In Silver Plume, Colo., there is a bachelor miner who offers individualized tours of his mine, The Silver Cloud. It is an interesting tour because he drove the mine himself and the view from the shack up there is spectacular. Beside that, he will probably invite you into his kitchen to sit around the old cook stove and drink coffee. When Andy first started his tour business he put a sign on the main street to advertise the fact. The sign read in part: "Women not welcome, but they will be tolerated at $3.00 a head”- the usual fee is $2.50. The sign lasted about 48 hours. Andy had to take it down because "all the ladies in town got mad at me. Now I take them all for $2.50 right across the board," he says. The mining industry is not only reticent about hiring women but traditionally does not even permit women to enter some mines. It would appear, what with the recent action on an equal-rights-for- women amendment in Congress, that we may be wise to examine the prospect.

Jan 1, 1970

By M. L. Trépanier

"Engineering and technical services are supplied by the Engineering Department, located at Thetford Mines, Quebec, approximately 60 miles southwest of Quebec City. The department serves the three operating mines in the Thetford area, the Asbestos Hill mine at Putuniq, Nouveau Quebec, and the Nordenham plant at Nordenham, West Germany. The Engineering Department is responsible for supplying the following services. 1. Administration and coordination of capital projects. 2. Engineering, design and drafting services for in-plant changes or improvements. 3. Preparation of geological plans for mine planning and ore reserves determinations. 4. Short-, medium- and long-term mining plans. 5. Rock mechanics studies and monitoring. 6. Grade control monitoring. 7. Environmental control engineering and construction. Details of the organization and services rendered will be the basis of the paper."

Jan 1, 1976

By W. M. Morris

THE volumetric behavior of isobutane at temperatures below its critical temperature has been studied by several investigators. Seibert and Burrell1 measured the vapor pressure of isobutane from the ice point to the critical temperature. Dana and co-workers2 determined among other thermodynamic quantities the density of the saturated liquid and the saturated gas and the vapor pressure from approximately 0° to 130° F. Sage and Lacey3 studied a number of the thermodynamic properties of this hydrocarbon from 70° to 250° F. The specific volume in the gas and liquid region was determined at pressures up to 3000 lb. per sq. in. ? throughout this temperature interval. In addition, the vapor pressures were measured at 30° intervals. These data taken together serve to establish the thermodynamic behavior of isobutane at temperatures between 0° and 250° F. with reasonable accuracy. However, apparently there are no data available at the higher temperatures. For this reason an investigation of the volumetric behavior of isobutane at temperatures between 100° and 460° F. was carried out with apparatus that has been described in another paper (A.I.M.E. Tech. Pub. 1127).

Jan 1, 1939

By Bernard Porter, E. A. Brown

Electrical conductivities and densities of the LiF- UF , LiF- ThF4 , NaF - C1F4 , and NaF - ThF systems were measured as functions of composition and temperature . The specific conductance and density varied linearly with temperature . Molar and equivalent volumes , as well as heats of activation for conductance , were calculated from the experimental data . At 1,000 ° C , the molar volumes ranged from 16 to 40 cubic centimeters per mole and the specific conductance ranged from 9.8 to 2.5 per ohm- centimeter as the actinide metal fluoride concentration changed from 0 to 60 mole - percent . Heats of activation for conductance were 3 to 7 kcal per mole . The data are interpreted on the basis of a semilattice model for the melts .

Jan 1, 1964

By M. S. Moats, C. M. Campbell

Samples of a high impurity (90.05 wt. % Cu, 4076 ppm Pb, 1939 ppm As and 635 ppm Bi) commercial copper anode were characterized and then electrorefined in a laboratory scale cell. Anode inclusions were examined using backscatter mode scanning electron microscopy and energy dispersive spectroscopy. Hundreds of inclusions were measured for size, morphology and composition. Commonly found inclusions were copper oxide (Cu2O), complex oxides (Cu-Pb-Bi-As-O) and copper selenides/tellurides. The weight percent of lead and arsenic increased with increasing inclusion size up to 4- 5 microns. During electrorefining, starter sheet ductility was negatively impacted by thiourea addition. The importance of arsenic (V) concentration on the electrolyte concentration of bismuth was observed. INTRODUCTION Copper electrorefining is a commercial process used to produce the majority of the world’s refined copper. During this process, impure copper anodes are dissolved electrolytically, and high purity copper is deposited on cathodes. As the anodes dissolve, the impurities either accumulate in the electrolyte or report to solids that form on anodes surfaces or at the bottom of the refining cell. These solids are called slimes. Slimes contain precious metals and are collected for further processing. Slimes are also an important outlet for problem impurities such as lead, antimony and bismuth. The electrorefining process is operated in such a way to encourage the deportment of these elements to the slimes. Impurities in copper anodes have been studied extensively by Chen and Dutrizac (1990, 1993 and 2005). The most common impurities found in modern copper anodes include: Ag, As, Au, Bi, Fe, Ni, O, Pb, Sb, Se, Sn and Te. Impure copper anodes are produced by pyrometallurgical methods and have purities ranging from 97.7–99.7% Cu (Moats et al., 2019). The composition ranges of commercial copper anodes from the 2019 worldwide tankhouse survey are given in Table 1. The concentrations of anode impurities vary widely dependent on the source material and prior processing steps. Based on the work of Chen and Dutrizac, both gold and silver are predominantly found in solid solution within the copper grains while a minor amount of Ag can be found in Cu2(Se/Te) inclusions. Nickel is entirely soluble within the copper grains up to anode compositions of 2500–3000 ppm Ni; above which NiO and kupferglimmer phases are formed (Chen & Dutrizac, 1990). As, Bi, Pb and Sb are found in solid solution within copper and within oxide inclusions typically found along grain boundaries. Oxides are formed due to the presence of 0.13-0.18 wt. % O (Chen & Dutrizac, 1990). This is because during solidification of the cast anodes, impurities are enriched in the liquid phase as the copper grains nucleate and grow. The inclusions form from the last liquid to freeze, which is typically along grain boundaries (Wenzl & Filzwieser, 2007; Wenzl, Filzwieser, Mori & Pesl, 2008).

Jan 1, 2019