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By Christoph Aichinger

A smart combination – Primetals Technologies developed the Circular Pelletizing Technology (CPT), which is a combination of the well-proven travelling-grate pelletizing technology with the design of a circular dip rail cooler of modern sinter plants. The overall space requirement and the installed weight for a CPT plant is significantly less compared to conventional technologies and by that CPT is a very attractive alternative for new projects.

Aug 16, 2017

By A. Porvali, V. Agarwal, M. Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2•H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can be treated further with NaOH solution to form REE hydroxides. This study focuses on metamodeling of a simulated flowsheet with design of experiments (DOE). Based on literature survey, a process flowsheet was developed using HSC Sim software. The created flowsheet focuses on circulation of solution containing Na+, K+, SO42- ions and impurities liberated in the NaOH treatment of double salt precipitate. The effect of seven parameters (P1-P7) on seven responses (R1-R7) were modeled using central composite design (CCD). INTRODUCTION Nickel metal hydride (NiMH) battery waste can be considered as an urban mineral due to the presence of valuable metals like: Ni, Co and rare earth elements (REE) (Larsson et al., 2013). In NiMH battery waste leaching experiments, sulfuric acid has often been employed as a lixiviant (Pietrelli et al., 2002,Zhang et al., 1999,Rodrigues and Mansur, 2010,Porvali et al., 2018). The key advantages of sulfuric acid are its stability and cost-effectiveness compared to other mineral acids such as HCl and HNO3. However, the usage of sulfuric acid in NiMH battery waste leaching poses simultaneous challenges and advantages. Limited REE solubility can be taken as benefit when recovering REEs double sulfates after solid-liquid separation. However, sodium and potassium hydroxide, present in electrolyte residues in the battery waste, can cause in-situ precipitation already during leaching due to limited solubility, thus decreasing the total REE recovery (Porvali et al., 2018). However, this problem can be circumvented by washing the electrolyte residues off the raw materials. Subsequently, the REEs may be precipitated in bulk as a mixed double salt out from the solution at very low pH with minimal co-precipitation of Ni and other metals. This relatively easy separation method can be extremely advantageous in the case of such a complex solution matrix with relatively high REE concentrations (conc.). Once REEs have been precipitated as double sulfates as per eq. (1) (Porvali et al., 2018), the resulting double salt precipitate lacks applications without further treatment. Direct thermal treatment would generate sulfur dioxide emissions and likely require high temperatures in order to transform double sulfates into REE oxides. Furthermore, the precipitate contains Na ions, which would need to be removed by chemical treatment from the calcined REE product. In the context of circularity of raw materials, it can be taken of a remarkable benefit if the sodium and sulfur present in the double salt could be reused instead of wasting them into the side streams. To that end, in this simulation study, the double salts are converted by dissolution and precipitation to hydroxides which are readily treatable, e.g. with total dissolution and solvent extraction, for further purification (Abreu and Morais, 2010):

Jan 1, 2019

By Judson G. Brown

In order to filter small amounts of fine slimy solids the reversible cake-filtration process was developed. The filterable solids contents lion in feeds can range from less than 1 ppm up to about 5%. The relative advantages of this process, are usually the greatest in the range of 0.05% to 1.0% filterable solids. Filterable solids that average in particle size about 20 microns& are non-compressible are very easy for this filtration process. Some feeds have been all sub-micron in particle size. A 1/8 inch thick cake is considered to be very thick. The usual cake is between 13/2 and 1/16 inch thick. A new line of injection molded plastic filter plates were developed for use with the reversible cake filtration process. The first commercial sized installation of this system was made 3 years ago in the Wakefield Y.M.C.A. swimming pool. Over 70 filters ranging in size from one plate to 63 plates have been produced. In addition to the process advantages there are the low cost and corrosion resistance advantages of the plastic plates.

Jan 1, 1962

By R. W. Jenkins, O. J. Neslage

The need for mechanized drilling to decrease mining costs has resulted in the development of the jumbo from column-and-bar drill carriages to hydraulically controlled jib jumbos. Resultant savings from use of improved jumbos have been high enough usually to retire the machinery investment within a year. The jib jumbo unit has been applied successfully to development and preparation programs and flat-bedded stopes, and an even wider field is forecast for its use.

Jan 1, 1950

By Simon C. Dominy, Patrick R. Stephenson, Alwyn E. Annels

Abstract - The often complex, erratic, and localized nature of gold is a common feature of many vein-style gold deposits. This style of mineralization is often referred to as being nuggety or possessing a high-nugget effect. As a result of these complexities resource estimation is difficult and in general, only Exploration Results can be provided or an Inferred Mineral Resource estimated from surface drilling data alone. Underground development, further drilling, and probably bulk sampling will be required to delineate Indicated and Measured Resources. Tonnages can generally be estimated from diamond drill and development information with a reasonable degree of confidence. Grade is much more difficult to define with confidence because it is commonly highly erratic and discontinuous in nature. The dependency of higher confidence Resource categories on development information may create a Catch 22 situation, with funding for such development often depending on the prior definition of at least Indicated Resources. There are no easy solutions to these challenges posed by high-nugget effect deposits, and it is important when classifying and reporting not to downplay the uncertainties often associated with Mineral Resource and Ore Reserve estimates for such deposits. However, in common with all deposit types, if the principles that underpin the estimation, classification, and reporting procedures are borne in mind and common sense applied, most issues can be satisfactorily resolved. This paper discusses the classification and reporting of Mineral Resources for high-nugget effect gold vein deposits within the framework of the JORC Code (JORC, 1999).

Jan 1, 2001

By J. K. Whyatt

The paper presents an approach to design a multi level room and pillar layout in a 40m thick seam overlain by a major aquifer. The design was required to maximise extraction with due consideration of the general stability of the workings, the potential water hazards, and spontaneous combustion risks due to air leakage between horizons. The approach utilised was a combination of empirical pillar sizing for water hazard control with numerical modelling to assess potential interactions between horizons. The numerical modelling allowed the size of interleaves, and the appropriate staggers to be optimised in terms of stress distribution. The stress distribution allows both the general stability of the openings and more importantly the permeability changes around the openings to be determined. The permeability of coal is sensitive to stress, and an empirical stress to permeability relationship, and theoretical permeability to flow leakage relationship has been applied to interpreting the relative spontaneous combustion risk associated with each of the proposed layouts. The final proposed design is a compromise between maximum exploitation of reserves and consideration of water hazards and of spontaneous combustion risk. Further more detailed design will be required as more comprehensive data on the geotechnical properties of the coal and overburden become available.

Jan 1, 1996

By Franz Ramstorfer

Impressões de Baumann são utilizadas amplamente nas aciarias para a avaliação e monitoramento da qualidade interna de placas: em particular a segregação central. A análise e monitoramento da segregação central é uma base importante do monitoramento da condição da máquina de lingotamento contínuo, da otimização dos parâmetros do processo de lingotamento contínuo e da qualidade das placas. Em geral, o tipo e a intensidade da segregação central são determinados através da comparação da imagem real com imagens de referência do padrão aplicado. O presente trabalho foi focado no desenvolvimento de uma ferramenta de análise computacional, precisa e fácil de usar pelos operadores do laboratório de Baumann. O objetivo foi estabelecer uma base padronizada e confiável para o processo de monitoramento da segregação central. A metodologia desenvolvida é baseada em processamento de imagem computacional de uma impressão de Baumann em tons de cinza. Observou-se que a classificação de segregação pode ser realizada com uma precisão excelente através da análise computacional dos dados de imagem da segregação central. O procedimento de classificação foi implementado com a utilização de uma rede neural feed forward.

Jul 29, 2018

By Robert Linton

SPECIFICATIONS for clays serving raw materials in the ceramic industry usually contain the following items: (1) Chemical analysis, sometimes with mineralogical structure determined by microscopic investigation. (2) Maturing temperature and firing range, usually expressed in terms of pyrometric cone equivalent. (3) Shrinkage (drying and firing shrinkage separately). (4) Degree of plasticity. (5) Color after firing. Clays may be classified, according to the purpose of the classification, in several different ways, based on (1) Geological occurrence-transported, altered An place, indurated (shales). (2) Physical properties-plastic (bonding clays, ball clays) and nonplastic (flint clays, kaolins or china clays, bone clays). (3) Color. (4) Use. A common classification of clays for commercial designation, and one fol-

Jan 1, 1936

By Jean P. Murray

The extractive metallurgical industry is a major consumer of high-temperature process heat. It is, consequently, a major contributor of C02 emissions and other greenhouse gases derived from the combustion of fossil fuels for heat and electricity generation, or from the process itself. These emissions can be substantially reduced by replacing fossil fuels with solar energy as the source of process heat. Concentrated solar radiation can supply a large amount of thermal energy to endothermic reactions at temperatures exceeding 2000 K. Another potential for C02 emission reduction exists as well. Thermodynamically, the total amount of energy required for metal production at any given temperature is the enthalpy change of the reaction, AH. Of this total, an amount equal to the Gibbs free energy AG must be supplied as high quality energy in the form of electrical work or by using a reducing agent. Many conventional metallurgical electrolytic processes and reducing furnaces are unable to add only the thermodynamically required electricaVchemical energy due to process inefficiencies. Electrical work in excess of AG for the reaction may be used to supply process heat, or excess chemical reducing agent burned to supply process heat. Besides the thermodynamic and economic drawback, this inefficiency results in excess C02 emissions derived from the combustion of fossil fuels. With these practices, energy becomes an important cost element of the metal produced. Highly-concentrated solar energy has the demonstrated potential to separate these two forms of process energies, allowing the addition of only the thermodynamically required high-quality energy while high-temperature solar process heat is provided to the reactor. Examples of metal oxide reduction processes that have been studied experimentally in solar furnaces include the production of Fe, Al, AI/Si alloy, Mg, Zn, Tic, Sic, CaC2, TIN, Si3N4, and AIN by carbothermic reduction of their oxides, and the high-temperature solar- electrothermal reduction of ZnO.

Jan 1, 1999

By Euclid P. Worden

In 1977, an article in World Mining (1) reported a total of 2726 rotary blast hole drills in service. This figure included only those machines produced by three of the manufacturers building drills of this type. The total, therefore, is much higher: Rotary drilling in the mining industry is big business to the manufacturers and suppliers involved, and a significant cost item, to mine operators. The time has come to take a hard look at rotary drilling technology with an eye to re¬ducing costs by increasing drilling efficiency. The efficiency of any rotary drilling operation is measured in terms of the rate of penetration achieved by the bit. In blast hole drilling, five factors affect the rate of penetration. They are: 1. Bit selection 2. Weight on the bit 3. Rotary speed 4. Hole cleaning 5. Formation properties Of these factors, all but one may be control¬led by the operator. Looking at any one in detail may reveal possible improvements in the system. Cleaning the hole is a good place to start. In order for a bit to perform at its maximum capability, each tooth or insert should strike fresh, clean rock as it falls into its drilling position. If the tooth or insert lands on previously drilled cuttings, a major portion of the energy delivered to the bit is absorbed in re drilling this broken material. A major portion of the interest, therefore, should be directed to the proper cleaning of the bottom of the hole.

Jan 1, 1979

By A. McMullen

"IntroductionTHE LOW-VOLATILE bituminous coals of the Brazeau field, Nordegg, Alberta, are soft and weak in structure. The seams contain .bands of inferior material, locally designated 'black jack', and thin bands of friable carbonaceous shale having no definite horizon but usually 'floating' in the seam. Because of the weakness• of the coal and the friable nature of the shale bands, run-of-mine coal usually contains a very high percentage of fines, as •Shown in the following table:SIZE WEIGHT. %Plus 1/2 in 25.61/2 – 1/4 in 13.31/4 - 1/8 in 14.6Minus 1/8 in 46.5The most convenient way of cleaning the fine coal would be by treating it in association with the coarse coal, so that no additional plant would be necessary. To a limited extent this is possible in certain types of equipment, notably the jig. A system of washing without pre-sizing is not •attractive, however, when dealing with the friable coal under consideration, which contains •a preponderant proportion of fines. At the new Brazeau washery, separation is made at 3/8-inch on •a Robins 'Vibrex' •screen, the coarse sizes being cleaned in •a standard pulsator-type jig. A feldspar jig is used to clean the minus 3/8-inch fraction."

Jan 1, 1954

By Thomas A. Mekelburg

Due to a tight ash constraint on the clean coal product and difficult middlings washability characteristics, a considerable amount of coal was being lost in the jig middlings at the Monterey No. 2 Mine. An investigation was conducted into circuitry to recover this lost coal with minimal effect on the total clean coal ash. A reverse two-stage hydrocyclone system cleaning at low specific gravities was selected. This system is currently recovering approximately 5.8 kg/s (23 tph) of 11.5% to 12.5% ash coal. The specific gravity of separation for the system is about 1.5 and the probable error is 0.13.

Jan 1, 1984

By R. E. Zimmerman

Wide attention is being placed upon various methods for cleaning the fine sizes of bituminous coals. The author describes and analyzes the results achieved on wet concentrating .tables of modern design on unclassified feeds of - 1/2 in. particle sizes, including tests on high-sulphur coals.

Jan 1, 1950

The notion prevails that writing is a knack, that the skilful use of the pen is a gift of nature. This is an error. Dogberry may be responsible for it; he said: "To be a well-informed man is the gift of fortune, but to write and read comes by nature". Because Dogberry said it, we may be sure that Shakespeare thought otherwise. Ability of any sort may be partly innate, but my own observation and experience lead me to conclude that most of the easy writers have become so by constant practice. As I recall the names of men successful with the pen, I remember that most of them have written a great deal and have taken particular pains to improve their style. The suggestion that proficiency in the difficult art is a happy accident provokes a sardonic smile. The larger part of the great writing in our literature is the result of persistent effort. An easy fluency has been the undoing of many; their flamboyant and fantastic scribbling has proved as perishable as froth. This criticism applies to technical writing also; in order that a technical description or discussion may hold the interest of the reader, at least long enough to cause him to read it to the end, the writing must be done carefully and systematically; otherwise it will fail in its purpose of conveying information. Clearness is absolutely essential. "It is not enough to use language that may be understood; it is necessary to use language that must be understood."* The purpose of writing, at least of that which is meant to be read by others, is not only to express ideas but to communicate them. Lack of perspicuity may prove as bad as

Jan 1, 1931

By T. A. Rickard

The notion prevails that writing is a knack, that the skilful use of the pen is a gift of nature. This is an error. Dogberry may be responsible for it; he said: "To be a well-informed man is the gift of fortune, but to write and read comes by nature". Because Dogberry said it, we may be sure that Shakespeare thought otherwise. Ability of any sort may be partly innate, but my own observation and experience lead me to conclude that most of the easy writers have become so by constant practice. As I recall the names of men successful with the pen, I remember that most of them have written a great deal and have taken particular pains to improve their style. The suggestion that proficiency in the difficult art is a happy accident provokes a sardonic smile. The larger part of the great writing in our literature is the result of persistent effort. An easy fluency has been the undoing of many; their flamboyant and fantastic scribbling has proved as perishable as froth. This criticism applies to technical writing also; in order that a technical description or discussion may hold the interest of the reader, at least long enough to cause him to read it to the end, the writing must be done carefully and systematically; otherwise it will fail in its purpose of conveying information. Clearness is absolutely essential. "It is not enough to use language that may be understood; it is necessary to use language that must be understood."* The purpose of writing, at least of that which is meant to be read by others, is not only to express ideas but to communicate them. Lack of perspicuity may prove as %ad as

Jan 1, 1931

By M Hawkins

The Clem Jones Tunnel (formally known as the North-South Bypass Tunnel), a A$2.88 billion road tunnel project in Brisbane, Queensland, was successfully completed almost seven months ahead of schedule. The project included two parallel 4.7 km long road tunnels, 740 m of intermediate roadway access ramps and two auxiliary ventilation tunnels. The tunnels incorporate intelligent tunnel systems, best practice fire and life safety standards and typical civil tunnel elements.Over the duration of the project the Parsons Brinckerhoff (PB) and AECOM (formally Maunsell) design joint venture (MPB) were Lead Designers to the Leighton Contractors and Baulderstone Bilfinger Berger Joint Venture (LBBJV). Construction of the toll road commenced in September 2006 and was completed in March 2010, with the tunnel opening then. Contributing to the success of this project was the continued support the lead designers gave throughout the construction period.This paper will focus on some of the structural elements that contributed to the success of the project – in particular the cable tunnel structure, a small precast, culvert shaped element under the pavement of the mainline tunnel, and the fit-out of the Gibbon Street shaft which were designed to be constructed in a combination of precast and in situ concrete.The cable tunnel was incorporated early in the design phase and runs the length of much of the tunnel. This paper will outline the challenges faced by the designers with implementing this system which provided significant construction advantages, among which were being able to install a separate ventilation duct during construction and to start fitting out the mechanical and electrical conduits and drainage system while tunnelling was still underway.The Gibbon Street shaft had a length and width of 20 m by 40 m and an overall depth of 38 m. A 20 m high structure of precast and in situ concrete was constructed in the base to accommodate mechanical and electrical equipment and provide a take-off access for the southern ventilation tunnel. The construction purpose for this structure was to provide a junction between the tunnel boring machine (TBM) and the roadheader-style tunnels, a staging platform for commencing the roadheader tunnelling, and a platform where the TBMs could be dismantled and removed.The design was assessed and reviewed many times throughout the construction process to address the needs of each of these stages. Innovative use of precast concrete was used to minimise construction time.Additionally, the designers provided support to the construction team from the time of design completion through to the tunnel opening. This meant that the changes to the design and adjustment of construction loadings could also be assessed. The fi nal outcome resulted in an efficient construction sequence and a project that has provided an excellent outcome for the client, stakeholders and community.

Mar 8, 2011

By Earnest R. Woakes

Those engaged in pumping from shafts, or other mining works, may be intereited in the following suggestion of what is believed to be a novel method of raising moderate quantities of water against a considerable head. It is admitted that the ordinary Cornish pump, as generally used in mines, is hard to beat, on account of both its extreme simplicity and its easy adaptation to the requirements of mining; its great drawback, however, being the enormous weight of heavy rods and successive plungers that have to be kept in motion, not to mention the necessary " balance-" and " angle-bobs," with all their accompanying friction and wear and tear. It is contended that the following method would, to a great extent, overcome these drawbacks ; though, no doubt, many old miners may say it would also introduce new ones. Possibly, this may be the case. It is only desired that this pump may be judged upon its merits. The chief novelty of the method consists in employing the almost unlimited pressure obtainable from a high column of water, augmented, if necessary, by a hydraulic ram or press at the top, to work a small-diameter piston or plunger at the bottom of a shaft or well. This high-pressure plunger, indicated at E, in Fig. 1, transmits power direct to a larger-diameter plunger, F, constituting, together with the ordinary H-piece, valves, and wind-bore, the actual pump, which raises the water, by column C, to the adit-level or other discharge, placed as far as possible below the head of the high-pressure column A and ram W. It will thus be seen, that it is only necessary to maintain a prmsnre on the small piston, E, equal to that on the larger one, F, by means of the small but high column of water, A, in order to cause F to descend, and thus force the water up through C. The up-stroke is accomplished by a small water-wheel, or other engine, connected to the light rod or wire rope B, this having only to raise the weight of the actual plungers and fill the H-piece with water from the tank or

Jan 1, 1892

By Frank Firmstone

It is proposed to consider here only comparisons made between results obtained when the materials employed are precisely the same, two furnaces at the same works for example, or the same furnace under different conditions as respects temperature of blast, method of charging, etc. With this limitation, the most important point in the comparison is the amount of fuel consumed per ton of iron. This, in fact, is the only item in the prime cost of the iron which can properly be said to vary in consequence of changes in the furnace process; for of the other principal items, the ore used per ton of iron, and also the amount of fluxing material, will depend on its richness, which, under the assumed conditions, will be practically invariable when taken over any considerable period; the labor cost also, from its nature, should be very nearly constant when estimated on the ton of iron. Moreover, as it consists principally in handling and moving material, it is greatly affected by circumstances quite independent of

By Walter Rosenhain

In selecting solid solutions for the subject of this lecture I have been guided by several considerations. The bodies known under that somewhat paradoxical name play a most important part in all types of alloys; consequently, a deeper knowledge of their constitution must 'be of fundamental importance to both metallurgical science and practice. Further, having been asked to deal with some of the more theoretical aspects of metallurgy, I have been tempted to describe certain considerations, which I believe to be novel, in regard to the nature of solid solutions. These considerations constitute a theory that requires much experimental confirmation, but they have passed the stage of speculations, for experimental evidence has become available and one inference after another, that can be derived from the theory, is found to be in accord with well-known facts. In putting before you these ideas and inferences, it must be understood that detailed quantitative proof of every step cannot be furnished. Our conclusions must therefore be stated with the reservation that their acceptance must depend on the manner in which the discovery of fresh facts may either confirm or confound them. If we wish to understand the structure of solid solutions we nust carefully realize the manner in which these bodies are formed in alloys. The formation of solid solutions is by no means confined to alloys, but it is desirable to confin5 attention, at the outset, to intermetallic solid solutions. It is not easy to formulate a precise definition of the term "solid solution." It may be said that a solid solution is a crystalline body formed from a liquid solution or from an intimate mixture of solids, or of liquid and solid, that retains in the solid state an admixture of the two substances (solvent and solute) as intimate as that which exists in a liquid solution. The term is undoubtedly paradoxical, for one usually associates solution with a liquid, but the difficulty cannot be evaded by using such a term as solidified solution, for this might refer to a solution that has set, or congealed, without undergoing crystallization. The German term mischkry stall avoids the difficulty and appears to

Jan 1, 1923

By Walter Rosenhain

In selecting solid solutions for the subject of this lecture I have been guided by several considerations. The bodies known under that somewhat paradoxical name play a most important part in all types of alloys; consequently, a deeper knowledge of their constitution must 'be of fundamental importance to both metallurgical science and practice. Further, having been asked to deal with some of the more theoretical aspects of metallurgy, I have been tempted to describe certain considerations, which I believe to be novel, in regard to the nature of solid solutions. These considerations constitute a theory that requires much experimental confirmation, but they have passed the stage of speculations, for experimental evidence has become available and one inference after another, that can be derived from the theory, is found to be in accord with well-known facts. In putting before you these ideas and inferences, it must be understood that detailed quantitative proof of every step cannot be furnished. Our conclusions must therefore be stated with the reservation that their acceptance must depend on the manner in which the discovery of fresh facts may either confirm or confound them. If we wish to understand the structure of solid solutions we nust carefully realize the manner in which these bodies are formed in alloys. The formation of solid solutions is by no means confined to alloys, but it is desirable to confin5 attention, at the outset, to intermetallic solid solutions. It is not easy to formulate a precise definition of the term "solid solution." It may be said that a solid solution is a crystalline body formed from a liquid solution or from an intimate mixture of solids, or of liquid and solid, that retains in the solid state an admixture of the two substances (solvent and solute) as intimate as that which exists in a liquid solution. The term is undoubtedly paradoxical, for one usually associates solution with a liquid, but the difficulty cannot be evaded by using such a term as solidified solution, for this might refer to a solution that has set, or congealed, without undergoing crystallization. The German term mischkry stall avoids the difficulty and appears to

Jan 1, 1923