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By S Hapugoda, J R. Manuel, M P. Ma, L Lu

Iron ore sinter quality depends heavily on the mineralogy, textures and physical structure of the sinter, which is formed upon solidification of the primary sinter melt. The interactions of the initial sinter melt with its surrounding materials will impact on the properties of the primary sinter melt and consequently the solidified structure of the sinter. By using a high-temperature visualisation system, in situ studies have been conducted on the effects of melt compositions (Al2O3, SiO2 and MgO) on the interfacial phenomena of the sinter melt on a natural iron ore substrate. It was found that the melt composition significantly influenced the wettability between the sinter melt and the iron ore substrate. The interactions between the sinter melt and the natural iron ore substrate were also examined. Such interactions can lead to further changes of sinter melt composition and hence the sinter melt properties that, in turn, further affect the wetting behaviour of the sinter melt.CITATION:Ma, M P, Lu, L, Hapugoda, S and Manuel, J R, 2013. Effects of melt composition on the interactions of sinter melt on a natural iron ore substrate, in Proceedings Iron Ore 2013 , pp 431-440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J. W. Freeman, E. E. Reynolds, A. E. White

Fram a study of 63 systematic alloy modifications it was found that molybdenum, tungsten, and columbium, added individually or simultaneously, and increases in chromium cause major improvements in 1200°F rupture strengths of Cr-Ni-Co-Fe base alloys. Rupture strengths were a function of the effect of composition modifications on both the inherent creep resistance and the amount of deformation the alloy would tolerate before fracture. THIS paper describes the results of an investigation of a series of alloys with systematic variations of the chemical composition of the following basic alloy: C, 0.15: Mn, 1.7; Si, 0.5; Cr, 20.0; NI, 20.0: Co, 20.0: Mo, 3.0; W, 2.0; Cb, 1.0; N, 0.12; Fe, 32.0 pct. The 62 modifications of this alloy were produced under conditions which minimized all factors influencing properties at high temperatures except composition. Melting, fabrication, and heat treatment were carefully maintained constant. Stress-rupture properties at 1200°F were used as the primary criteria of evaluation of the alloy. The objective of the study was to obtain data for determining the fundamental role of the influence of alloying elements on properties of heat-resistant alloys at high temperatures. In addition the results should be useful in determining optimum chemical compositions, the sensitivity of properties to variations in composition, and the degree to which alloy content could be reduced while retaining worthwhile properties. It is difficult or impossible to develop correlations between properties at high temperatures and systematic variations in chemical composition from published data for wrought heat-resistant alloys developed for gas turbines.' ' The main reason for this is the extreme dependence of the properties on conditions of treatment of the alloys." In most cases variation in final treatments between alloys so influences the properties that the influence of chemical composition is obscured. In addition it is recognized Table I. Basic Alloy and Some Modifications Used Basic AllOy, Variations in Element Pct Composition, Pct C 0.15 0.08. 0.40. 0.60 Mn 1.1 0.03,0.25.0.50,1.0,2.5 S1 0.50 1.2, 1.6 Cr 20.0 10, 30 Ni 20.0 0, 10,30 Co 20.0 0. 10, 30 MO 3.0 0. 1.2.3, 5, 7 W 2.0 0, 1, 5, 1 Cb 1.0 0.2,4,6 N 0.12 0.004, 0.08, 0.18 Fe 32.0 that variations exist between heats of the same alloy which are related to melting practice and that there is a strong possibility that conditions of hot working influence response to final treatments. The development of heat-resistant alloys has been based on the gradual accumulation of data roughly related to composition from extensive testing programs. There is every reason to believe that in most cases the optimum compositions have been achieved by this procedure in the alloys commercially available. There are, however, very little data showing the influence of systematic variations of composition free from the influence of other factors, particularly for alloys of the type investigated. Several investigators of cast alloys have demonstrated compositional effects, notably Grant,1-6 Epremian,t Guy,8 and Harder and Gow.9 Sykes10 eviewed the work on the wrought alloy Rex 78 and the systematic variations of carbon, copper, molybdenum, and cobalt leading to the development of the stronger Rex 337A alloy. From the papers by Wilson11 and Henry12 it is possible to deduce the beneficial effect of substituting cobalt for iron in 0.45 pct C-20 pct Cr-20 pct Ni-4 pct Mo-4 pct W- 4 pct Cb alloys. Wilson mentioned but did not present the extensive compositional studies involved in developing these alloys. Binder" showed optimum properties for 3, 2, and I pct, respectively, for molybdenum, tungsten, and columbium in 20 pct Cr-20 pct Ni-20 pct Co-30 pct Fe alloys for limited systematic variations of these

Jan 1, 1953

By M. McWha

Laboratory bias is a universal problem in all branches of analytical science. It results from differences in methods, techniques, equipment, and calibrations between laboratories. Notwithstanding that it is a property that can be measured by the use of standards or by inter-laboratory testing, laboratory bias remains a material issue for the mining industry. There is extensive literature and clear guidelines on measurement from the International Organization for Standardization (ISO) and its worldwide federation of national standards bodies (ISO member bodies) and from the science of metrology. ISO guides cover the manufacture and use of standards. An accessible source of literature covering laboratory quality control comes from the public health sector, particularly pathology. There is little doubt in financial reporting rules about the meaning of materiality. Public reporting guidelines are clear that material matters need to be disclosed for investors. Unfortunately there is currently no clear guidance what to do about biased assay results in mineral industry public reporting guidelines. This paper reviews the requirements for the manufacture and use of reference materials, public reporting requirements in the mining industry, and presents proposals to improve management and reporting of laboratory biases. Keywords laboratory bias, reference materials, ISO Guides, financial reporting, materiality.

Jan 1, 2014

By Crazy Horse - The Journal of Explosives Engineering - Vol 20 No 1

The crew at Crazy Horse Memorial has produced a w o n d e rful new video called “The Fine Art of Mountain Carving.” The video closely examines for the first time, the extraordinary explosives engineering on the Crazy Horse mountain currently in pro g ress in the Black Hills of South Dakota. The 56-minute video takes the viewer up the mountain for a behind-the-scenes look at the drilling and blasting crew at work on the mountain. The video was written, edited and produced by Robb D e Wall and is available exclusively from the Crazy Horse Memorial in both DVD and VHS formats. For i n f o rmation, see www.crazyhorsememorial.org The following, is a brief summary of the 25 steps involved in carving the mountain. The video goes into extensive detail on each of the 25 steps. Both those in the explosives industry and those outside the industry will find the video intere s t i n g .

Jan 1, 2004

By Wenting Zhu, Liqing Chen, Junjun Cui, Zhenye Chen

In this presentation, a low carbon high strength steel microalloyed with Nb and Ti was processed by thermo-mechanical controlled process (TMCP) containing two stages of controlled rolling. The austenite with various grain sizes was obtained by austenitizing this hot-rolled steel at different temperatures. And the effect of austenite grain size on bainitic transformation was investigated in a dilatometer to reveal microstructural change. The results showed that the microstructure of the hot-rolled steel was mainly composed of granular bainite, lath-like bainite, and martenite/austenite constituents (M-A constituents). With increasing the austenitizing temperature, or increasing the austenite grain size, the microstructure was changed from granular bainite to lath bainite. When the steel was reheated to a lower temperature of 860 ºC, a relatively higher start temperature (Bs) was measured for bainitic transformation. This was mainly caused by the formation of solute-depleted region in the austenite and the promotion of the granular bainitic nucleation. The highest reaction rate occurred at austenitizing temperature of 1000 ºC with fine grain size, while the coarse austenite grain can lead to a sharp increase in the amount of bainite. An analysis was made on the kinetics of bainite transformation which was controlled by the volume diffusion of C atom.

Oct 1, 2019

By Kazuyuki Kikuta

MMAJ, a govemmental organization in Japan, has carried out a 4 year project for the development of the decontamination and metals recovering technology for the fly ashes from municipal waste incineration. Heavy metals (zinc, lead and copper) are recovered as raw materials for the non-ferrous metals production, without formation of any waste materials to be disposed. More than 500 thousands tonnes a year of fly ashes generation from the municipal waste incineration has been one of the main social issues in Japan, because most of them need to be disposed to the registered areas after decontamination, and occupy 5% of the municipal wastes disposed. The segregation, flotation and chemical process are applied to the treatment of the primary fly ash from municipal waste incineration, and MF (Mitsui-type blast furnace) Process after the chlorine removal to the secondary fly ash. The main results of experiments are -About 90% of heavy metals, zinc, lead and copper, can be recovered from the primary and the secondary fly ashes to the products for the non-ferrous metals production. -Both of the leaching residue from the primary fly ash treatment and the slag from the secondary fly ash treatment can be used as a raw material for the cement production, meaning that the decontamination technology for the ashes without the landfill has been established. -Dioxins in the primary ash can be decomposed satisfactorily, and the dioxins content in the segregation furnace gas is less than O.lng-TEQ/Nm3 without any gas cleaning system

Jan 1, 2003

By C. W. Chen

MARTENSITE transformations in ß Cu-Al alloys have been studied by Greninger1 and other investigators. According to Greninger, the parent phase ß1 an ordered body-centered-cubic structure obtained from ß phase by suppressing the eutectoid decomposition, transforms into an ordered hexagonal-close-packed phase in composition containing 12.9 to 14.7 pct Al. The M, temperature decreases with increasing aluminum content; for the alloy containing 14.5 pct Al, for example, the ß1??' transformation occurs below room temperature. More recently, Kurjumow2 studied the transformation in ß Cu-Al alloys with the addition of nickel. His report stimulated new interest in the subject due to the observation of completely reversible transformation without hysteresis in the transformation temperature ranging from 10° to —10°C. In the present paper some characteristics are described of the transformation of Cu-Al-Ni alloys that were partly studied by Kurjumow. Experimental Procedure High purity copper (99.999 pct) and aluminum (99.99 pct) and electrolytic nickel were used in the preparation, by the Bridgman technique, of single crystal specimens which contained aluminum and nickel of 14.5 and 0.5 to 3.0 pct, respectively. Polished surfaces were prepared mechanically. Specimens were then chemically etched to remove distorted material, homogenized at 1000°C for several hours, and quenched drastically to room temperature in a 10 pct NaOH bath to produce the parent phase ß1. The transformation was studied under a microscope and, in some cases, recorded by means of motion pictures. A device similar to that designed by Greninger and Mooradian3 was used to cool and reheat the specimens. Results and Discussion When the specimens were cooled below room temperature, the ß1 to ?' transformation began at 10°C with the appearance of ?' crystals In relief, Fig. la. As the specimen temperature dropped further, the transformation continued, either by the growth of the ?' crystals, with the ß1 — ?' interface moving into the ß1 phase, Fig. 1c and 1d, or by the formation of new ?' crystals, Fig. 1b. As a consequence of the former process, banded structure is observed as a common feature of the low temperature phase. According to the theory of the formation of martensite by Wechsler, Lieberman, and Read,' the bands of ?' phase are probably twin-related, as is the case in the diffusionless phase change of In-T1 alloys,5 but this was not revealed by X-ray tech- niques. New ?' crystals, in needle form, often emerged suddenly across the ?' bands during the transformation. These acicular crystals then grew, both in length and in width, see Fig. 2a through 2d. The transformation on cooling is completed at about -35°C. Upon heating, the reverse transformation started at —10° C, in a manner nearly opposite to the transformation on cooling, and completed at 35°C. There was no noticeable change in the transformation temperature when the nickel content was varied within the limits previously mentioned. Through control of the specimen temperature, the transformation can be started, stopped, or reversed at will. This phenomenon has frequently been observed in the martensite transformation of many nonferrous alloy systems. Other systems are Au-Cd6 and In-Tl.5 ow-- ever, in the latter systems, the transformation is accomplished by single interface motion if the specimen composition is homogeneous and the temperature gradient in the specimen is uniform and sharp, whereas in the Cu-Al-Ni specimens, only multiple interface transformation is observed. The speed of the interface motion appears to be a functionof the rate of temperature change and the temperature gradient across the specimen length. In one case, in which the temperature increased at the rate of 10°C per min and there was no temperature gradient along the specimen axis, the speed of the disappearance of a ?' plate was determined, by the study of the motion pictures made, to be 26 µ per sec. Quench markings were observed on the polished surfaces of specimens. The markings were grouped into one or more sets of different orientations, and were parallel in each set. The ?' plates formed in subsequent transformation were parallel to the markings, indicating that the ?' plates and the quench markings had the same geometric relation-ship to the ß1 matrix. The quench markings on two intersecting surfaces of a specimen were therefore used in the determination of the habit plane of transformation, by the trace method suggested by Barrett.' Results obtained from five sets of markings in three specimens indicate that the habit plane is an irrational plane about 2" from one of the {221} planes. This is very close to the habit plane (3" from 221 planes) of ß Cu-Al alloys containing more than 13.0 pct Al.1 The martensite transformation of Cu-Al-Ni alloys is reproducible. No sluggishness was found between consecutive transformation cycles, although a slight difference in the distribution pattern of the ?' plates was observed, compare Figs. Id and 2d. The transformation can be strain-induced. This characteristic has been tested by a simple method. When a specimen was elastically strained slowly in a vise, ?' plates were gradually produced in the same fashion as during transformation on cooling, This test was done at room temperature, and thus above the M,

Jan 1, 1958

By M. A. Creaney

"The Construction Group is responsible for the construction of all of Placer Dome’s major projects and contributes to the development of most major feasibility studies. This group includes an international collection of Placer Dome people who have built mines in Papua New Guinea, Australia, Chile, the United States and Canada. This paper outlines the changing role of the Construction Group from the early days of single projects to today, when several projects are in various phases from feasibility to construction. The projects’ total annual budgets have from time to time exceeded one billion dollars. IntroductionAs the competition increases globally between the major gold mining companies, the impetus continues to build mines at the lowest cost with the shortest construction schedule. Placer Dome has more than met that challenge by building mines around the world at a pace that was not contemplated 15 or 20 years ago. Since 1960, Placer Dome has built 30 mines and expansions at a cost of nearly 4.5 billion dollars.In the last six years alone, Placer Dome has built 14 mines and expansions, worth 2.6 billion dollars. The company’s success is due primarily to Experience, Innovation, People and Standards.The diversity between projects, let alone the pace, has been a challenge. Placer Dome has built mines around the world in a variety of extreme climates and distinctive cultures. The construction experience gained from these projects has allowed Placer Dome to develop an extensive knowledge and data base making it easier to “fast track” projects.Through the years Placer Dome has developed a human resource base. It now has an experienced and adaptable core team of people able to set up construction projects and build mines anywhere in the world. By developing standards and systems to support the projects they can act as soon as a new project is approved, and complete the projects quickly and effectively. The result is that Placer Dome now has the construction expertise to build its own mines, giving them the competitive advantage that allows them to design and construct a mine in the least time at the lowest capital cost. This was demonstrated in March 1997 with the completion of the construction of two new mines in 12 months."

Jan 1, 1998

By V. O. Tenorio, J. Puell

"Dump design is critical to effective mine planning in large scale open pit mines. Capital and haulage costs are considerable from early stages and through the life-of-mine as these dumps gradually become immense structures. Delivered mining rates, as well as certain spatial and physical constraints, provide a set of parameters of mathematical and economic relationship that creates opportunities for modeling and thus facilitates the measuring and optimization of ultimate dump design by using programming and empirical techniques while achieving economic objectives. This paper presents a methodology to optimize the ultimate dump design by minimizing its total dumping costs. The methodology consists of the formulation of a generalized model based on the relationship of the main dump parameters, followed by the use of linear programming to find the solution that minimizes the haulage total cost, and finally through a series of iterations, modifies the preliminary solution by projecting it to the topography and creating the ultimate dump design. A case study applied to a waste dump exemplifies this methodology. INTRODUCTION Open pit mine operations move large amounts of material on a daily basis from the shovel faces to the appropriate destination points. Hustrulid et al. identified three major destination places where the material receives downstream treatment after its delivery: mill processing, leaching dumps, and waste rock dumps [1]. The corresponding destination is given by a cut-off grade criteria, ore type, and the possibility of obtaining the maximum metal recovery. Dump leaching technologies have developed substantially since 1975 [2], and have enabled mining facilities to beneficiate low grade sulfide and oxide ores. As a consequence, the number of active dumps have increased since then and the entire mine configuration, which is limited in itself, has changed. The proper location, design, and construction of a mine dump must serve the safety, environmental and economic goals of the long-range mine plans. Therefore, an optimized use of the available surface area in the mine is highly desired."

Jan 1, 2018

By Andrey V. Tarasov

To carry out a physicochemical substantiation of a transition to ?soft? modes of reduction of calcine obtained by desulfurizing roasting of nickel concentrate produced as a result of copper-nickel converter matte separation in a nickel anode production circuit, an analysis has been conducted of the macrokinetic behavior of actual calcine samples in the presence of gaseous H2-CO mixtures and solid reductant additives. Within a temperature range of 900°C to 1100°C the main regularities typical of the calcine reduction process with individual gases (H2, CO) also take place when using a gaseous mixture. Under the conditions of low-temperature (900°C to 1000°C) nickel oxide reduction with products of fuel oil conversion in the presence of coke, the role of the latter is insignificant from the technological viewpoint. As a result of the present investigations, we have obtained analytical expressions of macrokinetic parameters of the reaction interaction within the [NiO] calcine-H2-CO-C-CO2-H2O-O2-N2 system.

Jan 1, 2005

By E. L. Kinsella, F. S. White

Solids fluidization utilized in two ways for the commercial production of lime is described. Crushed —6 mesh limestone is dried and dedusted in a single bed reactor, then calcined in a 5-stage reactor. Construction, operation, and results obtained with both processes are given. THE solids fluidization process brought out by the Standard Oil Development Co. in the early forties for catalytic cracking of petroleum enabled rapid transfer of large quantities of heat from gases to solids under closely controlled temperature conditions. As the technique developed, it was natural that applications for the process outside the petroleum industry would be sought. The calcination of limestone to quicklime requires the transfer of a large quantity of heat at high and closely controlled temperatures. For these reasons, this possible application was one of the first to be investigated. Laboratory work conducted by the Dorr Co. indicated that lime produced by solids fluidization would be of exceptional quality. Calculation of theoretical heat balances showed that savings in fuel could be expected. Accordingly, a pilot plant of 10 tons per day capacity was erected by the New England Lime Co. at Adams, Mass., to substantiate the process. Operation of the pilot plant, previously described,' showed that excellent lime could be produced with a saving in fuel. The work also indicated the necessity of preparing feed to remove the finer fractions if dust losses were to be held to a tolerable level. A single-stage fluidized solids drier-stripper was developed to accomplish this sizing.' Subsequently a commercial lime reactor was erected at Adams, beginning operation in June 1949, followed by air sizer facilities completed in November 1951. This paper will describe these two applications of solids fluidization. The raw material for preparation of lime by the fluidizing process is a high calcium crystalline lime- stone having the approximate chemical composition shown in Table I. The stone is first prepared by crushing and grinding in conventional equipment to pass a 6-mesh sieve. After crushing, the material is sent to the FluoDry unit for drying and dedusting. Fluidized Drying and Sizing As shown in Fig. 1, the FluoDry unit consists of a -in. cylindrical steel shell, 9-ft ID by 22-ft 6-in. overall height. Attached horizontallv at the bottom is a 6-ft diam combustion chamber, approximately 7 ft 6 in. long. A refractory constriction dome, consisting of first-quality fire brick shapes, partitions the inside into two sections. The lower section is called the windbox and the upper the bed compartment. The vertical wall of the shell is lined with 6-in. first-quality rotary kiln blocks. In the bottom of the windbox a hoppered section is formed with castable refractory to permit the windbox to be readily cleaned via a 6-in. screw conveyor. The combustion chamber is similarly lined with refractory shapes. On the 6-in. diam section, 4 in. of insulating brick, HW-26, are used. The inner combustion chamber is lined with 4-in. Korundal brick to withstand the high flame temperatures encountered. An 8-in. steel feed pipe, entering vertically through the top and fitted with an air-operated cone valve,

Jan 1, 1953

By F. S. White, E. L. Kinsella

Solids fluidization utilized in two ways for the commercial production of lime is described. Crushed —6 mesh limestone is dried and dedusted in a single bed reactor, then calcined in a 5-stage reactor. Construction, operation, and results obtained with both processes are given. THE solids fluidization process brought out by the Standard Oil Development Co. in the early forties for catalytic cracking of petroleum enabled rapid transfer of large quantities of heat from gases to solids under closely controlled temperature conditions. As the technique developed, it was natural that applications for the process outside the petroleum industry would be sought. The calcination of limestone to quicklime requires the transfer of a large quantity of heat at high and closely controlled temperatures. For these reasons, this possible application was one of the first to be investigated. Laboratory work conducted by the Dorr Co. indicated that lime produced by solids fluidization would be of exceptional quality. Calculation of theoretical heat balances showed that savings in fuel could be expected. Accordingly, a pilot plant of 10 tons per day capacity was erected by the New England Lime Co. at Adams, Mass., to substantiate the process. Operation of the pilot plant, previously described,' showed that excellent lime could be produced with a saving in fuel. The work also indicated the necessity of preparing feed to remove the finer fractions if dust losses were to be held to a tolerable level. A single-stage fluidized solids drier-stripper was developed to accomplish this sizing.' Subsequently a commercial lime reactor was erected at Adams, beginning operation in June 1949, followed by air sizer facilities completed in November 1951. This paper will describe these two applications of solids fluidization. The raw material for preparation of lime by the fluidizing process is a high calcium crystalline lime- stone having the approximate chemical composition shown in Table I. The stone is first prepared by crushing and grinding in conventional equipment to pass a 6-mesh sieve. After crushing, the material is sent to the FluoDry unit for drying and dedusting. Fluidized Drying and Sizing As shown in Fig. 1, the FluoDry unit consists of a -in. cylindrical steel shell, 9-ft ID by 22-ft 6-in. overall height. Attached horizontallv at the bottom is a 6-ft diam combustion chamber, approximately 7 ft 6 in. long. A refractory constriction dome, consisting of first-quality fire brick shapes, partitions the inside into two sections. The lower section is called the windbox and the upper the bed compartment. The vertical wall of the shell is lined with 6-in. first-quality rotary kiln blocks. In the bottom of the windbox a hoppered section is formed with castable refractory to permit the windbox to be readily cleaned via a 6-in. screw conveyor. The combustion chamber is similarly lined with refractory shapes. On the 6-in. diam section, 4 in. of insulating brick, HW-26, are used. The inner combustion chamber is lined with 4-in. Korundal brick to withstand the high flame temperatures encountered. An 8-in. steel feed pipe, entering vertically through the top and fitted with an air-operated cone valve,

Jan 1, 1953

By Jan Bak

Rourkela Steel Plant (RSP), which is operated by the Steel Authority of India Limited (SAIL), was inaugurated in 1959 and was the first Integrated Steel Plant in the public sector in India. In 2013, RSP commissioned their No. 5, 4060 m³ Blast Furnace, India's largest. It was built as a turn-key project by a consortium consisting of Danieli Corus and Tata Projects Ltd. and is entirely based on the technology and know-how of Danieli Corus. The new Blast Furnace is the key element of an expansion program that doubles the plant's production capacity and with much of the existing ironmaking capacity reaching the end of its technical and economic life span, it enables RSP to meet existing as well as growing demand for its products. This article discusses how this greenfield Blast Furnace was built in an existing and operating Integrated Steel Plant. It covers the accommodation of land, planning of the new installation to fit the available plot as well as the updated logistical lay-out of the plant. Technical details of the installation are presented, including their consequences for RSP's environmental performance and new perspectives for campaign planning.

Aug 2, 2018

By Wenbin Liu

A novel route for rapid synthesis of ultrafine WC-Co cemented carbides with homogeneous binder phase distribution is reported. The composite powder is produced by in situ reduction-carbonization reactions by using WO2.9, Co3O4 and carbon black as raw powders. The reaction equilibrium and phase stability are studied by thermodynamic calculations. The WC-Co composite powder is condensed by spark plasma sintering (SPS) to obtain the cemented carbides bulk. The sintering temperature is lower than that in the conventional sintering methods by 1500C, while the sintering time is remarkably reduced by 3-5 times. The high performances of the hardness and the fracture toughness are obtained. The experimental results confirm that the present processing scheme of in situ reduction-carbonization reactions and subsequent SPS sintering is an efficient way to prepare WC-Co cemented carbides, and is apparently superior to the conventional long-period techniques of preparing composite powder and cemented carbides bulk.

Jan 1, 2008

By Michael S. Wieland

The work-principle method was developed for theoretically resolving toxic fumes from non-ideal charge formulations. The whole description of a wanted process refers to macroscopic changes resulting from removing and imposing constraints that work one at a time to chronologically render trajectory terminal (key) states. The trajectory resolution utilizes a thermodynamic quasi-potential or negative work function, and numeric results require some appropriate standard thermodynamic (equilibrium) reaction code TDRC. The underlying method is unable to restrict reactions, tailor the work output or resolve states within the trajectory transitions, so the trajectory terminology is used somewhat figuratively. The work-principle model has the working fluid (reaction material) interacting with a tremendous reservoir (chamber air and walls), while forecasting the work performed upon a mechanical agent.

Jan 1, 1998

By Julia Pflieger, Manfred Russ, Johannes Gediga

This paper shall show an economic feasible approach to implement Greenhouse Gas (GHG) reduction measures into the mining and metallurgy industry. The goal to improve energy consumption is directly linked to the reduction of GHG emissions and therefore directly in correlation with the economic viability. A baseline scenario of the considered reference system and of the respective reference year has to be defined, mapped and analysed. In a second step an analysis of the same operation using available and prospected Best Available Technology (BAT) processes is carried out to generate a basis for a benchmark system. The identified reduction potentials are reported and the GHG emission reductions are put into relation to the investment cost of the new process technologies / process adaption to be implemented. This economic feasibility calculation is necessary to realise a cost efficient GHG reduction roadmap implementation into the company's business operations. The GHG reduction roadmap is developed using ratios between GHG reduction and investment / operating cost to get an indication for a sequence for implementing carbon emission reductions measures.

Jan 1, 2010

By Wenxian Zhu, Xuema Li, Patrick R. Taylor

"Experiments were performed in a non-transferred arc, thermal plasma flow reactor to investigate the synthesis of ultra fine boron nitride (BN) powder from the reaction system of boron oxide (Bz03), methane (CH4), ammonia (NH3) and hydrogen (H2). Argon (Ar) and nitrogen (N2) were used as plasma gases. The thermodynamics and kinetics of the synthesis reactions were examined and a chemical reaction mechanism was proposed. The powders produced under certain operating conditions had high purity and good conversions. All the products were extremely fine powders (< 30nm) and were uniform in size distribution. The powder products were analyzed by chemical and physical characterization. The effects of the reaction variables on the conversions from B203 to BN and the purity of the products were investigated.IntroductionIn the past few decades, boron nitride (BN) has attracted a great deal of interest because of its excellent thermal, chemical and electrical properties (1-4) It has a high thermal stability and thermal conductivity. Chemically, it is very stable and is not wetted by most molten metals and slag. It is also an excellent low loss insulator. Since hexagonal boron nitride (h-BN) is light in weight, strong and easily fabricated, it has applications in a variety of specialized high temperature areas, such as a high temperature lubricant, crucibles for molten metals, thermocouple protection tubes, break rings for horizontal continuous casting of steel, and friction reducing coatings. In cubic form, boron nitride is one of the hardest materials known, second only to diamond, and it is an excellent material for tools in which the use of carbon based materials is limited by oxidation or reaction with metals."

Jan 1, 1998

THE North Mount Lyell Mine is situated on the southern side of Mount Lyell at an altitude of 1750 ft. above sea-level. The average rainfall is 117 in., and there are generally several light falls of snow during the year. Despite the heavy rainfall, which is fairly evenly distributed over each of the twelve months, the climate is equable and not unduly rigorous, and, provided that the mine employee is suitably clad, it is only on exceptional days that he experiences any discomfort by becoming wet journeying to and from the mine.The majority of employes reside at Queenstown, and are conveyed by special trains to and from the top of the haulage, which is less than a mile from the mine. The mean surface temperature at the mine is 46&#176; F., with a maximum variation from 26&#176; F. to 85&#176; F., the relative humidity generally being higher than in other districts. The rock temperature is 48&#176; F. on the 200-ft. or Main Adit level, and 54&#176; F, on the 1200-ft. level, giving a rise of 6&#176; F. for 1000 ft. in depth.The ventilation of the mine is natural, the downcast being served by the Crown and Blocks shafts and the Crown mullock pass, and the upcast air is carried away from the workings by the Main shaft and the Nos. 1 and 2 mullock passes. The quantity of air circulating varies from 25,000 cub. ft. to 35,000 cub. ft. per minute, the greater quantity moving in the colder weather. The downcast air in traversing the wet shafts becomes saturated and enters the level at the rock temperature of 54&#176; F. in winter and about 56&#176; F. in summer, while temperature readings of the outcast air indicate that it varies very little.In the southern end of the mine the Blocks shaft downcast air upcasts through the different stopes, and their mullock passes, to the level above for each level to the 700-ft. level, where it passes to one of the main uptakes. The prown shaft downcast air supplies...

Jan 1, 1927

By Kenneth L. Maloney

Ten small and intermediate-sized [11 GJ/hr to 264 GJ/hr (10,000 lb/hr steam to 250,000 lb/hr steam)] coal-fired boilers in the upper Midwest have each been tested on both a bituminous eastern coal and a subbituminous western coal. The purpose of this study was to determine the feasibility of substituting western subbituminous coal for eastern bituminous coal as a means of reducing the SO x emissions from this class of boiler and to demonstrate the feasibility of greatly expanded western coal utilization as a means of reducing the use of oil and gas. The scope of this study was such that the representative boiler types were tested on both eastern and western coal for a period of time sufficient to completely characterize their individual emission and operational characteristics.

Jan 1, 1977

By David Kress

Mill crushing drive systems are essential to cement producers. With the increased emphasis on operating efficiency, it is vital that these systems be dependable and reliable. No one needs the costs or headaches associated with unscheduled downtime or inefficient machinery operation. A reliable drive system starts with the proper selection of the ring, or girth, gear and continues through proper maintenance. Ideally, selecting the right girth gear brings together the gear manufacturer, the system designer and the end user. The gear manufacturer must know the details of the application, the demands that will be placed on the gear and the nature of the equipment to be driven. Similarly, the user and the system designer must be familiar with the variables that affect gear drive performance and service. For example, an application that places a torque load on the drive in excess of its rated capacity will result in gear tooth distress and, in severe cases, breakage.

Jan 1, 2000