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By JOURNAL SAIMM

SYMPOSIUM ON PELLETS AND GRANULES During October 1974, the Newcastle branch of the Australasian Institute of Mining and Metallurgy is to hold a symposium on pelletizing and granulation, with particular reference to the iron ore, fertilizer, and cement industries.

Jan 12, 1973

By Roland Kammel

In combination with various physical and chemical methods also electrochemical techniques are most frequently used to improve the recovery of metals from aqueous dilute process streams or effluents e.g. in electroplating, metal finishing, mining and metallurgical plants. To insure cathodic metal recoveries with favorable current efficiency and high throughputs per unit of cell volume seve¬ral types of electrolysis cells have been developed comprising extended electrode surface areas and/or intensive electrolyte. agitation. The practical experiences with these units indicate especially for the electrolytic recovery of metals whose values are high, that the treatment cost permits profitable operations with relativly short payback periods for the units. Anodic reactions can be utilized for the removal of undesired anion contents or buildups of impurities. Appropriate combinations of these recovery methods are used to improve the versatility and the overall economy. Industrial applications reveal their potentional as addidtive techniques for existing processes to reduce the metal content of effluents to values that meet the guide lines of environmental legislation whereas integrated in-operation recovery methods are nowadays increasingly introduced to approach nearly close-loop operations.

Jan 1, 1992

By John Chipman, Helen Towers

DEVELOPMENT of a simple radioactive tracer technique for measurement of the diffusion coefficient of calcium ion in liquid slag has already been reported. The investigation was of a preliminary nature designed to explore the possibilities of using radioactive isotopes and to establish a method, and no great accuracy was claimed for the results. It was shown, however, that Ca15 could be used successfully, and the values obtained for the diffusion coefficient appeared to be of the right order of magnitude. However, it was considered that a better technique could be devised for carrying out the diffusion. The experiments were, therefore, continued to find a more accurate method, to check the calcium results, and to extend the investigation to include measurements of the diffusion coefficient of silicon in the same slag. There were two flaws in the original technique. Convection was the cause of too many failures, and the interface between the two slags in the diffusion cell was curved rather than plane, probably due to a surface tension effect caused by the addition of the tracer Ca45 in the form of chloride. Two methods of overcoming these defects were tried. Since it was planned to study diffusion of the short-lived isotope Si"' also, the development of methods was restricted to those which gave promise of being reasonably rapid. Method 1—The principle was identical to that previously used with respect to the diffusion conditions, but there were three differences in technique. Temperature control was more rigid, the tracer was added to the slag as Ca45O rather than the chloride and, finally, an effort was made to translate to high temperatures the elegant method developed by Cohen and BruinV or bringing together the two liquid layers and beginning the diffusion. A master slag was melted in graphite, ground to a fine powder, and analyzed (38.5 pct Ca0-20.9 pct Al2O3-40.5 pct SiO2). The tracer was received as Ca45C12 in an aqueous solution of CaC12 + HC1. From this, calcium oxalate was precipitated, ignited to calcium oxide, and added as such to the slag to give an activity of approximately 5 µc per g. The mixture was then melted into the form of a cylinder 3/16 in. diam and about 1 in. long. A solution identical to the tracer solution without Ca45 was given exactly the same treatment. The resulting Ca40O was mixed with that slag which was to form the tracer-free half of the diffusion cell, and this was likewise melted into a cylinder of the same size. Slag cylinders, two with and two without Ca15, were set in graphite blocks as shown in Fig. 1, and the crucible was lowered into position in the fur-

Jan 1, 1958

By May Nyman

Due to the vast diversity of chemical media in which metal separations are executed, a wide range of ion separation materials are employed, This ,results in an ongoing effort to discover new phases with novel ion exchange properties. We present here the synthesis of a novel class at, thermally and chemically stable microporous, niobate-based materials. Ion exchange studies show these new phases are highly selective for Sr2+ and other bivalent metals.

Jan 1, 1999

By Dr. Daniel W. H. Su

t is both an honor and privilege for me to nominate Dr. Daniel W. H. Su for the inaugural Syd S. Peng Ground Control in Mining Award. I can think of no better candidate than Daniel that is deserving of this award ? an award to recognize technical excellence in advancing ground control technologies [and] approaches. Daniel?s education and career spans over three decades. Having graduated from National Cheng Kung University in Taiwan in 1972 with a B.S. degree in Mining and Petroleum Engineering, he spent the next four years in the Taiwanese military and mining industry, before moving to the United States, where he enrolled in West Virginia University?s Mining Engineering Department. He received his M.S degree in Mining Engineering from WVU in 1978; then in 1982 became the first person to ever receive a Ph.D. in Mining from WVU. His thesis was titled, ?Development of Ultrasonic Techniques for the Measurement of In Situ Stresses?.

Jan 1, 2006

By Jr. Taylor

The following heats of solution have been measured in 1.160 molal H2SO4 at 25° C: AH298, kcal./mole Be(c) + 77.44(H2SO4?47.849 H2O) H2(g) + BeSO4 (soln) -92.83 ± 0.11 BeSO4 ?(c) + 77.44 (H2SO4?47.849 H2O) BeSO4(soln) -16.45 ± 0.02 BeSO4?2H2O(c) + 77.44(H2SO4?47.849 H2O) BeSO4?2H2O(soln) -5.395 ± 0.019 BeSO4?4H2O(c) + 77.44 (H2SO4?47.849 H2O) BeSO4?4H2O(soln) 1.513 ± 0.010 Combining these data with other experimental results and data taken from National Bureau of Standards information yielded the following heats of formation at 298° K:

Jan 1, 1966

By C-D. Johansson, B. Ögren, B. M. Ludvigsson, K-Å. Johansson, R. Lindh, G. Berg, M. Maliarik

This paper presents the High Current Density (HCD) Silver Electrorefining Process. A 25-year history of development of the silver electrorefining process as well as associated equipment is given. The process is simple and robust, but at the same time highly automated. With low operating costs and man power requirement it allows consistent production of 99.99 % quality cathode silver. The process ensures that no toxic gases are formed in the working environment. Silver Electrorefining is a heart of a Silver Refinery plant covering the complete range of processes from casting of silver Doré anodes to casting of the bars of refined silver or/and silver granulation. The process has been successfully applied at 11 installations world-wide with plant capacities ranging from 30 to 1500 tpa.

Jan 1, 2014

By J. C. D. Gush

Paper written on project work carried out in partial fulfilment of Laboratory-scale testwork was undertaken to recover oxidic copper-cobalt minerals by froth flotation, which requires maintaining a certain sulphide level in the pulp. To improve control of the sulphide concentration, an electronic closed-loop system was designed that responds to the potential output of an ion-selective electrode. The PID control was improved by adding a pre-emptive control and a self-calibration feature; a data logging facility is also included. An inexpensive valve design was incorporated using locally available parts. The operating results of this control design are presented.

Jan 1, 2005

By Sue Ritz

Gold extraction has relied on coconut carbon in adsorption circuits for several decades. IXOS®, invented by 6th Wave Innovations of Salt Lake City, Utah, is a new type of adsorbent that exceeds the selectivity of carbon and improves on the mechanical properties of other available resins. IXOS selectivity against copper cyanide complexes allows it to be used in circuits that currently struggle with copper contamination. IXOS potential to eliminate or reduce the application of SART technology will expand the opportunities to exploit more complex precious metals deposits. This paper will describe the technology behind IXOS molecular imprint, its comparison to carbon adsorption in the field, and the effect of efficiency on long-term recovery from heap leach METSIM simulation software.

By K. Mukai, M. Ishihara

This report is a brief discussion of the impurity levels both in primary aluminum and super-purily alnminim in connection with raw materials and proc-essing methods. Particularly, truce amounls of im-purities were analyzed by introducing nittss-speclro-gruphy and nenlron-aclivalian analysis techniques. Vanadium and gallium content in primary aluminum metal corresponded to theor amounls in anode coke. but the nickel content in primary aluminum was hide-pendent oj its amount in the anode cake. Sulfur in the anode colic might result in an increase of the iron content in the molten metal in the reduction cell. The content of sodium and calcium increased with increasing bath ratio. In the holding furnacc sodium content decreased rapidly, and nonmetallic inclusions merit separated front the mollen metal. Three-layer elctrolysis was effectire in eliminating many impuri-ties with the exception of copper, aluminum oxide. aluminum nitride, and some rare-earth elements. THE amount of impurities and nonmetallic inclusions in aluminum metal depends on impurities in the raw materials and various production processes. This paper presents an investigation of the behavior of impurities and nonmetallic inclusions in aluminum during the electrolysis process, the period in the holding furnace, and the process of three-layer electrolysis. Chemical analysis and emission spectrometric analysis have generally been used as methods to determine small amounts of impurities in both primary aluminum and super-purity aluminum; however. mass spectrography and neutron-activation analysis have been recently introduced into this field, and trace amounts of impurities can accurately be determined by these latter methods. EXPERIMENTAL WORK Common impurities were determined by means of absorptiometric. polarographic, flame-photometric. and emission-spectrometric methods. However, in the determination of trace amounts of impurities and non-metallic inclusions, the following methods were applied. In the analyses of trace impurities by mass-spec- trographic analysis, samples were exposed in the vacuum spark of double-focus ing Mattauch-Herzog type mass spectrograph (Japan Electron Optics Laboratory, Ltd.). Ilford Q2 photographic plates were used as ion detectors. Fe was used as the internal standard, and the atomic concentration of each element was calculated by the following expression and converted into the weight concentration: where E, and Ei are the exposures (coulomb) when isotopes of the internal standard and impurity elements (on which the estimate is based) show the same density, X is the percent (atomic) concentration of the standard, IF and Ii are the percent abundances of the isotopes of the standard the impurity elements (on which the estimate is based), and Ms and hfi are the mass of the isotopes of the standard and impurity elements (on which the estimate is based). The coefficient of variation in this method is about 40 pct in the range of 0.1 to 1 ppm. In neutron-activation analysis, irradiations were done in the nuclear reactors TRIGA-I1 (neutron flux: 4.7 x 10 11 n per sq cm per sec; Rikkyo University) or JRR-2 (neutron flux: 2 x 1013 n per sq cm per sec: Japan Atomic Energy Research Institute). After the chemical separation, a NaI (3 by 3 in.) scintillator connected to a 256-channel y-ray spectrometer (R.C.L.) was used for counting and recording various activated impurities. The coefficient of variation in this method is about 20 pct. In the analyses of nonmetallic inclusions, aluminum-oxide determination was carried out according to Fischer's method, 3 as follows. A slice of sample was cut off and the surface was cleaned. It was dissolved in bromine-methanol. The solution was filtered and the residue was washed. The residue was fused with potassium bisulfate flux. Then it was dissolved in weak acid, and oxine solution was added. The aluminum oxinate was extracted with benzene. Finally, aluminum was determined absorptio-metrically. Aluminum nitride determination was carried out as follows. A slice of sample was cut off and the surface was cleaned. It was put in the distillation apparatus and decomposed with sodium hydroxide solution. The solution was distilled. Then ammonia was absorbed and

Jan 1, 1967

By E. Guerrini, M. Maccagni, J. Nielsen

"The solution for the treatment of the EAFD has not yet been fully achieved. Some of this dust has still not found an appropriate final destination. Large consortium treatment plants are quite expensive both in terms of investment and operating cost. Meanwhile, the tolling expenses for steel production companies are becoming very important, causing them to look for alternatives. Some steel plants are looking to close their production loop by internal treatment of their dust. Some years ago, Engitec began studying the coupling of the EZINEX® Process, an ammonium chloride electrolysis to recover the zinc contained in the EAFD, with the INDUTEC® Process, a pyro process based on an induction furnace that can convert EAFD into a C.Z.O. similar to the Waelz oxide. The combination of these two processes provides an alternative to the existing treatment options and is particularly interesting for relatively small capacities. In this paper, we would like to give the latest update about these two processes and their possible integration INTRODUCTION Zinc is contained in numerous wastes and secondary raw materials that can be thought of as high zinc concentrate mines. This is a very interesting source of Zn that is typically easily exploitable. Unfortunately, only a portion of these materials are currently processed to recover the metal value, while stabilized or unstabilized landfilling is often the final destination. Pyrometallurgical processes are mainly used to convert the zinc into crude zinc oxide (CZO). The various processes are very similar and characterized by the fact that the zinc bearing materials are usually submitted to a thermal treatment [1] in which the zinc is reduced, vaporized and re-oxidized producing CZO. This material not only contains zinc oxide, but also relatively high concentrations of heavy metals. Many potential CZO sources, such as electric arc furnace dust (EAF), galvanizing ashes, brass foundry and converters fumes also contain chlorides, fluorides and alkali metals that will transfer to the CZO. The classic example is the Waelz oxide [2]. This CZO is an intermediate product that must be transformed into zinc salts or zinc metal. Until now, the conversion to zinc metal is done through two main processes: the sulphate leaching and electrowinning system and the Imperial Smelting Process (ISP). ISP is facing a crisis for technical and economic reasons that has led to the closing of most of the existing plants. In any case, before being fed to one of these two processes, the CZO must be treated to eliminate or reduce some of the contained impurities. In particular, the halides are most harmful to these processes."

Jan 1, 2018

By E. Guerrini, M. Maccagni, J. Nielsen

"The solution for the treatment of the EAFD has not yet been fully achieved. Some of this dust has still not found an appropriate final destination. Large consortium treatment plants are quite expensive both in terms of investment and operating cost. Meanwhile, the tolling expenses for steel production companies are becoming very important, causing them to look for alternatives. Some steel plants are looking to close their production loop by internal treatment of their dust. Some years ago, Engitec began studying the coupling of the EZINEX® Process, an ammonium chloride electrolysis to recover the zinc contained in the EAFD, with the INDUTEC® Process, a pyro process based on an induction furnace that can convert EAFD into a C.Z.O. similar to the Waelz oxide. The combination of these two processes provides an alternative to the existing treatment options and is particularly interesting for relatively small capacities. In this paper, we would like to give the latest update about these two processes and their possible integration INTRODUCTION Zinc is contained in numerous wastes and secondary raw materials that can be thought of as high zinc concentrate mines. This is a very interesting source of Zn that is typically easily exploitable. Unfortunately, only a portion of these materials are currently processed to recover the metal value, while stabilized or unstabilized landfilling is often the final destination. Pyrometallurgical processes are mainly used to convert the zinc into crude zinc oxide (CZO). The various processes are very similar and characterized by the fact that the zinc bearing materials are usually submitted to a thermal treatment [1] in which the zinc is reduced, vaporized and re-oxidized producing CZO. This material not only contains zinc oxide, but also relatively high concentrations of heavy metals. Many potential CZO sources, such as electric arc furnace dust (EAF), galvanizing ashes, brass foundry and converters fumes also contain chlorides, fluorides and alkali metals that will transfer to the CZO. The classic example is the Waelz oxide [2]. This CZO is an intermediate product that must be transformed into zinc salts or zinc metal. Until now, the conversion to zinc metal is done through two main processes: the sulphate leaching and electrowinning system and the Imperial Smelting Process (ISP). ISP is facing a crisis for technical and economic reasons that has led to the closing of most of the existing plants. In any case, before being fed to one of these two processes, the CZO must be treated to eliminate or reduce some of the contained impurities. In particular, the halides are most harmful to these processes."

Jan 1, 2018

By Hassan Saalman, Mahmoud Mahmoud, Omneya El Hussaini

The Ferruginous sandstone ore was obtained from Ramlet Hemeyir area, Southwestern Sinai, Egypt, was found to contain 10% rare earth elements (REE). A representative sample has been subjected to sulfuric acid agitation leaching. About 93% of the REE content was released by mixing the ground sample to -100 mesh with concentrated H2SO4 at solid/liquid (S/L) ratio of 1/2 for 5h at a temperature ranged from 250 to 300o C. The REE was precipitated from the prepared sulfate leach liquor of pH 1.0 by adding 35% oxalic acid at 25o C. The precipitation yielded 98% REE. For selective separation of yttrium, the rare earth cake was leached with 31.5% nitric acid. Next, the aqueous solution was contacted with di-(2-ethylhexyl) phosphoric acid (D2EHPA) where 98% yttrium extraction was achieved. Stripping was done with hot H2O (80o C). Finally, a precipitation with oxalic acid was done followed by ignition at 950o C. A yield of 95% yttrium oxide was produced.

Jan 1, 2014

By C. G. Anderson

Industrially proven and applied nitrogen species catalyzed (i.e. NSC) acidic pressure leaching has been utilized to treat a number of ores, concentrates and recycled materials. This versatile technology offers many advantages including low temperatures, low pressures, low capital costs, low operating costs, faster throughput and less costly materials of construction than conventional pressure oxidation. This paper will elucidate the application of this technology for production of gold, silver, palladium, rhodium, zinc, germanium, gallium, cobalt, copper, molybdenum, rhenium and nickel. Recycled material applications will also be elucidated. In addition, details of an application for treatment of a refractory chalcopyrite copper and gold bearing ore will be presented and pertinent economics discussed.

Jan 1, 2014

By Young Hyun Paik, Hyung Sup Choi, Yeun Sik Kim

The basic studies on the surface properties and flotation characteristics of ilmenite were made by electrophoretic, adsorption, contact-angle and floatability measurements. The isoelectric point of ilmenite is found to be at pH 5.6. By combining the results of electrokinetic studies and adsorption measurements, a clearer picture of the ilmenite-solution interface was observed. These findings were correlated with the floatability of ilmenite obtained by Hallimond tube tests. The general flotation characteristics of ilmenite are compared with those obtained for magnetite and rutile. It is indicated that the above three minerals, namely, ilmenite, magnetite and rutile, have very similar surface properties and flotation characteristics. Therefore, it is difficult to make an effective separation of these minerals by flotation. However, it is found that sodium orthophosphate acts as a selective depressant for magnetite in anionic flotation. Therefore, close pH control of the pulp in the presence of the phosphate ion enhances the possibility for a successful separation of these minerals.

Jan 1, 1967

By Zhihao Yue, Honglie Shen, Yahui Teng, Ye Jiang

"In this paper, manganous nitrate [Mn(NO3)z] was used to assist the etching of silicon wafer in hydrofluoric acid (HF) for the antireflective application, and alumina (Al2O3) layer was deposited on the surface of the etched sample by atomic layer deposition method for further antireflection. The surface morphological and compositional studies of these samples were performed by scanning electron microscopy attached with an energy-dispersive X-ray spectrometer. The surface reflectance measurements were carried out using UV-Vis-NIR spectrophotometer. Binary structures of pyramids and nanopores were obtained by etching the alkaline textured monocrystalline silicon wafer in HF and Mn(NO3)z mixed solution for not more than 15 min. But excessive increase of etching time of up to 30 min resulted in the whole destruction of pyramids. The average reflectances of the 5-min-etched sample before and after being coated with 75-nm-thick Al2O3 layer are 4.62% and 3.47% in the range of 200-1000 nm, respectively.1. IntroductionAs we know, the reflectance of silicon wafer after being sliced is so high that the maximal photoelectric conversion efficiency of silicon based solar cells is limited. Therefore, alkaline texturization process was used for silicon solar cell in industrial production. But the reflectance of this alkaline textured wafer is still greater than 10% and this process can only be used for monocrystalline silicon solar cell."

Jan 1, 2013

By F. W. Jones

The perturbation of alternating electromagnetic fields by three-dimensional structures is considered. The general model is that of a semi-infinite conducting half -space which consists of regions of different conductivities. A numerical method is used to obtain the solution for the equations and boundary conditions. The effects on the fields at the surface of the half-space due to the conductivity discontinuities are shown by three-dimensional amplitude and phase plots.

Jan 1, 1973

By AIME AIME

THE American copper mining industry is threatened with disintegration and destruction. This threat is not one which may only materialize in the distant future. The destruction has already commenced. At present, many domestic mines have already closed down. .Others are operating on a greatly curtailed basis. Those operating are doing so only at tremendous loss-because the selling price of copper is below the cost of production and rapidly diminishing financial resources and credit clearly forecast the early suspension of operations in most of the industry. Unemployment in the mining districts is increasing by leaps and bounds. While this condition is due in some measure to the present unsatisfactory state of business in general, the copper industry, unlike other lines of business, sees no possibility of recovery without definite aid. The fundamental, underlying cause of present conditions in the American copper mining industry is the unprecedented rise in foreign production, and the basic change which has taken place in the world copper industry in the last three years. The American industry had begun to feel this change early in 1929 long before the general collapse of business in the fall of that year. While the distress in the industry is undoubtedly aggravated by the present economic depression, it nevertheless would have arrived and. have been present at this time, regardless of general business conditions.

Jan 1, 1932

Polarization phenomena associated with the use of an agitated bed of particles as an electrode for metal deposition were studied. The concentration polarization at this type of electrode is much smaller than that occurring at a fixed or moving electrode surface. Agitated particle electrodes can be used to electro-reduce copper from solutions over a wide range of concentration and at cur·rent densities up to 2000 AIsq. ft. of bed cross section.

Jan 1, 1971

By William J. Campbell

The purpose of this investigation was to develop a rapid, accurate method of analysis for small amounts of calcium in wolframite concentrates. This analysis is necessary to determine if the wolframite concentrates meet United States National Stockpile Specification P-57R2, which limits the calcium content to 0.2 percent. Because of the small depth of the sample analyzed in fluorescent X-ray spectrography, the calcium Kaline intensity was a function of the chemical composition of the calcium-bearing particle as well as the total matrix composition. This particle-composition effect was particularly important in this analysis, as the calcium may be present as a carbonate, tungstate, phosphate, etc. Three methods of preparing the sample eliminated the variation of calcium Ka intensity with mineralogical occurrence: (1) Reduction in particle size by extensive grinding, (2) chemical fusion with sodium carbonate, and (3) solution of the calcium by an acid attack.

Jan 1, 1958