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By B Rouvray, R Bertuzzi

The development of a design-and-construct tunnelling project in Australia from its concept to its construction requires designs to be prepared and reviewed at several distinct stages prior to documenting ‘for construction’. On recent projects the post-tender stages have been variously called 30 per cent—70 per cent—100 per cent; or concept–substantial–final; or system definition–preliminary–critical. The design is reviewed at each stage by the designer’s internal reviewer, the contractor and its independent advisor(s), the owner and its independent advisor(s), the project’s independent certifier, proof engineers and often third-party stakeholders and their advisors. Documentation for each stage often dominates the design effort, at times distracting from design. This paper presents the authors’ experience of this design-and-review process. Comparisons of design budget and actual design spend and design program implications are presented. It is postulated that a subtle change has occurred in our industry that has diminished the value of the design dollar. Is there a better process? An alternative is suggested.CITATION:Bertuzzi, R and Rouvray, B, 2014. Reducing the cost of tunnel design in Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 501–506 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By K Henley

One of the greatest practical difficulties of measuring airblast occurs when a significant wind is blowing onto the microphone. Small windscreens are usually used to mitigate the wind noise on the microphone, but in some wind conditions, sound pressure levels (SPL) of over 120 decibel (linear) are frequently recorded. There are no specific procedures to mitigate the effect of wind noise when measuring airblast in any of the standards or guidelines pertaining to the measurement of airblast from blasting operations, other than the requirement to use an effective windscreen. A search for relevant literature was undertaken and measurements were taken over a period of six months at a test site using alternative microphone measurement methods. Previous researchers’ experiments with windscreens in silenced wind tunnels showed that wind noise can be reduced through the use of large diameter windscreens, and that at low frequencies, the windscreen size and the material type makes no difference to measured SPL values. Other researchers found that wind turbulence caused significant SPL measurement problems. A comparison with field data failed to explain the extremely high SPL recorded by the field microphones at wind velocities much lower than those used in wind tunnel testing. It has been concluded that turbulent airflow over and behind the microphone is a significant contributor to extraneous noise in airblast measurements in windy conditions. This turbulence can be generated by objects upwind of the microphone or by the microphone itself if the windscreen is ineffective. Reducing the wind speed over the microphone by placing it on the ground is the approach required by the international standard for the measurement of noise from wind turbine generators (IEC 61400–11). This paper presents data that illustrates the extent of the problem, reports on the trial of three different microphone mounting locations for measuring airblast from blasting and concludes that in windy conditions, microphones placed on the ground substantially avoid wind problems and do not reduce the measured SPL of the airblast.CITATION:Henley, K, 2015. Reducing the effect of wind on airblast measurement during blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 485–492 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By A Tsang, D La Rosa, L Julian, W Hunt, R Pratama

Mineral extraction is facing the twin challenges of finite resources and increasing environmental and economic costs. Society’s growth is matched by an increase in demand for the earth’s resources. It is incumbent on us as contemporary mining professionals to promote and facilitate ethical and efficient practices. Technological developments have and will continue to allow a decrease in viable cut-off grades, creating new economic opportunities from deposits that were previously uneconomic. Mining low-grade deposits however, even with perfect recoveries, will have a significant environmental cost for the metal won. The greatest opportunity to increase metal with the least environmental cost is to increase the metal yield from existing mines. The determination of mining polygons is a critical juncture where rock is typically subjected to the binary grading of either ore or waste. This is undertaken using a number of factors, such as the mining equipment being used and the recovery in the processing plant. Traditionally, mining polygons were generated on the in situ grade control model. This ignores the complex differential blast dynamics that occur during blasting. Two opportunities exist to improve metal yields: optimise the blast design to achieve the post-blast muck pile that will support the greatest outcome; and generate optimised polygons on the post-blast muck pile. A data set from a Canadian Gold deposit is used to demonstrate the potential benefit of iterative blast movement modelling and grade control polygon optimisation on metal yield. The impact of blasting on the total recoverable metal is presented, highlighting blast design as a critical process in the mining value chain.

Sep 1, 2024

By W. D. Monaghan

Flame cutting and welding is one of the major causes of fires and explosions in underground U.S. coal mines. On May 20, 2006, a flame cutting operation at the Darby Mine No. 1 led to an explosion that resulted in five fatalities. On January 22, 2003, another explosion caused by flame cutting at the McElroy Mine resulted in three fatalities and three serious injuries. On June 22, 1999, a flame cutting and welding operation at the Loveridge Mine caused a fire that resulted in sealing of the mine for an extended period. Finally, on March 19, 1992, an explosion at the Blacksville No. 1 Mine that was caused by welding resulted in four fatalities. The National Institute for Occupational Safety and Health (NIOSH) conducted a study on fires and explosions in underground U.S. coal mines that were caused by flame cutting and welding operations to determine the root causes of these types of fires and explosions. The methodology included interviewing mining personnel who perform flame cutting or welding operations in underground U.S. coal mines and visiting mines to observe these operations, and MSHA reports of investigations and accidents statistics were analyzed. The results were used to identify and compare differences between flame cutting and welding practices and techniques in small and large mines, Eastern and Western mines, low seam and high seam mines, room and pillar and longwall mines, and between experienced miners and new miners. As a result of this study, best practices and interventions were developed to reduce the number of fires and explosions caused by flame cutting and welding. This paper provides a summary of this work. Disclaimer: The finding and conclusion in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupation Safety and Health.

Jan 1, 2009

By W. D. Monaghan

One of the major ignition sources of fires and explosions in underground U.S. coal mines is flame cutting and welding. On May 20, 2006, a flame-cutting operation at the Darby Mine No. 1 led to an explosion that resulted in five fatalities. On Jan. 22, 2003, another explosion caused by flame cutting at the McElroy Mine resulted in three fatalities and three serious injuries. On June 22, 1999, a flame-cutting and welding operation at the Loveridge Mine caused a fire that required sealing the mine for an extended period. On March 19, 1992, an explosion initiated by welding at the Blacksville No. 1 Mine resulted in four fatalities. These examples of mine incidents demonstrate the need to conduct research to develop best practices for safely conducting flame cutting and welding in underground coal mines. The National Institute for Occupational Safety and Health (NIOSH) conducted a study on fires and explosions in underground U.S. coal mines that were caused by flame-cutting and welding operations to determine the root causes of these types of incidents. The methodology included interviewing mining personnel who perform flame-cutting or welding operations in underground U.S. coal mines and visiting mines to observe these operations. In addition, MSHA reports of investigations and accidents statistics were analyzed. The findings were used to identify and compare differences between flame-cutting and welding practices and techniques in small and large mines, eastern and western mines, low-seam and high-seam mines, room-and-pillar and longwall mines, and between experienced miners and new miners. As a result of this study, best practices were developed to reduce the number of ?res and explosions caused by flame cutting and welding. This paper provides a summary of this research.

Jun 1, 2010

By Neal I. Rosenberg

There is an old education maxim that a good teacher "first tells 'em what he's gonna tell 'em, then he tells 'em, and finally he tells 'em what he told 'em. I'm sure this says something about me as a teacher, and therefore as a student as well, but I'm going to begin by violating that maxim. The first thing I'm going to do is tell you what I'm not going to tell you. I'm not going to tell you that my company has found the solution to frozen coal problems. I'm not going to tell you that there is a miraculous new formula, and your frozen coal worries are over. Actually, it is really questionable whether there is a single step or process which will provide the answer. On the other hand, I do believe that at Union Electric we have made significant improvements in our ability to deal with frozen coal over the last couple of years, and I propose to describe some of the things we have done, what conclusions we have drawn so far, and the direction in which we are now headed. It would be well here to give a brief picture of the Union Electric system and the frozen coal problems we face. Union Electric is an investor owned electric utility with headquarters in St. Louis, Mo. Total generating capability is on the order of 6800 megawatts, which snakes us 24th or 25th largest in the United States. Power generation is by steam (both coal and oil fired), hydro, pumped hydro, and combustion turbine units. Although that is a diverse power supply, by far the largest source is our four coal fired steam plants. One receives coal exclusively by barge, the other three by rail. It is at these last three plants that the frozen coal difficulties arise.

Jan 1, 1980

By M. Laliberte

Gold mine effluents are often characterized by a high concentration of copper, ammonia and cyanide derivatives (mostly cyanates and thiocyanates). While non-acutely toxic to birds, this water can be acutely toxic to fishes and invertebrates. In many jurisdictions, the effluent requires further treatment in order to pass a mandatory requirement to be non-lethal to species like the rainbow trout (Oncorhynchus mykiss) or Daphnia magna. Using actual mine water, it has been demonstrated that aerated moving bed biofilm reactors will biodegrade the ammonia, cyanides, cyanates and thiocyanates, thereby removing the toxicity associated with these components. By removing copper by precipitation the water can be made to pass acute toxicity tests. Tests have demonstrated that the process is stable between 4 and 25 C, with no significant changes in the treated water composition. Once the biomass is acclimatized, the process is resistant to upsets and requires very little inputs except for phosphorus and air. Furthermore, it has been demonstrated that an anoxic reactor can be added downstream of the aerated reactors to remove nitrates if required.

Feb 23, 2014

By M. Laliberte

"Gold-mine effluents are often characterized by high concentrations of copper, ammonia and cyanide derivatives (mostly cyanates and thiocyanates). While not acutely toxic to birds, this water can be acutely toxic to fishes and invertebrates. In many jurisdictions, the effluent requires further treatment in order to pass a mandatory requirement to be nonlethal to species like the rainbow trout (Oncorhynchus mykiss) or Daphnia magna. Using actual mine water, it has been demonstrated that aerated moving bed biofilm reactors will biodegrade the ammonia, cyanides, cyanates and thiocyanates, thereby removing the toxicity associated with these components. By removing copper by precipitation the water can be made to pass acute toxicity tests. Tests have demonstrated that the process is stable between 4 and 25°C, with no significant changes in the treated water composition. Once the biomass is acclimatized, the process is resistant to upsets and requires very little inputs except for phosphorus and air. Furthermore, it has been demonstrated that an anoxic reactor can be added downstream of the aerated reactors to remove nitrates if required.IntroductionThis paper will demonstrate that gold-mine effluents, which are toxic to fishes and invertebrates, can be made nontoxic by using a combination of chemical precipitation and biological oxidation.The typical composition of gold-mine effluents will first be described. The applicable legislation will then be introduced, with its requirement that the treated effluent be nontoxic. The toxicity of a typical untreated effluent will then be confirmed, and the sources of the toxicity identified. After that, a number of toxicity reduction treatment methods will be presented, and the selected method will be described.The lab tests that confirmed the efficiency of the treatment method will be presented, with three phases of testing as the understanding of the process gradually improved. Toxicity test results showing that the water is nontoxic after treatment through the temperature range will be presented."

Jan 1, 2015

By J A. Rowland

When executing a ventilation change the mine ventilation circuit is in a state of flux throughout the entire change period with discrete mine areas both under ventilated and/or over ventilated during the change process. Whilst routine risk reduction strategies such as removing electrical power and people from the mine are commonly deployed it is wise to complete the change in the shortest practical time frame. This not only minimises the chance of unacceptable concentrations of contaminants accumulating around the mine but reduces the impedance on production activities which are routinely suspended during these change periods. This paper firstly highlights the importance of the maintenance of an accurate ventilation model and discusses issues which should be considered to assist to maintain in it a suitable state of health. Further it provides some tips on how to monitor that your model is in an acceptable state of tune so that it can be confidently deployed in the change process. Finally, it details the sequential process how a finely tuned and accurate ventilation model can be utilised to carry out major ventilation changes according to appliance pressure adjustments only and without the need to constantly measure and check resultant branch flows throughout the whole change process. Also discussed are some simple practical tips which will help ensure that the ventilation change process will go according to the devised plan on the day and in the most appropriate order including checking the efficiency and accuracy of the change, after it is completed.

Oct 12, 2022

By N Lima, A Piçarra, L Filippov, I Filippova, M Marques, K Silva

The iron industry produces a considerable amount of tailings per annum, due to its substantial volumes of production. The actual iron ore processing routes require the removal of slimes fractions. In addition to iron oxides and quartz, the iron ore slimes are generally composed of other minerals such as kaolinite and finely dispersed iron hydroxides which impact significantly the performance of reverse cationic flotation. In this study, we propose a two stage processing route that would allow further beneficiation of iron slimes which are not successfully beneficiated, avoiding their disposal as waste. The new amidoamine reagent was tested as a collector in a two-stage route to process two samples of iron ore slimes with d50 close to 10 μm and with high kaolinite content (13 to 20 per cent). The results showed that it was possible to obtain iron concentrate with 66.5 per cent iron and 48.4 per cent mass recovery for a feed containing 48.9 per cent Fe associated with hematite (39 per cent) and goethite (32 per cent). The collector efficiency was improved by mixing with frother for the slimes with higher goethite content of 55 per cent: the concentrate grade was increased from 58.8 per cent to 64.5 per cent with addition of the frother at the expense of reducing operation metallurgical recovery from 87.8 per cent to 75.6 per cent. The efficiency of the process was improved by applying an external energy impact to disperse the fine particles and clean the surface of the minerals. The new amidoamine collector does not require a depressor such as corn starch and may provide the development of new concentration routes for complex ultrafine iron ores. The combination of the amidoamine-based flotation at first stage with high intensity magnetic separation allowed development of optimised two-stage processing routes to valorise the iron ore slimes rejected to the tailings in the actual flotation plant.

Sep 18, 2023

By C. R. Kuzell

GEOGRAPHICAILY the industry of reducing and refining of copper continued to migrate from the .United States during 1931. While this country is losing the predominant position of its copper industry, our engineers still enjoy their pre-eminent position as leaders in the design and operation of the new plants being brought into production in the four quarters of the globe. Progress in the art, as indicated by the construction of the recently completed works, has not been revolutionary. Standard methods have been followed, augmented by novel features in flow-sheets demanded by the results of progress in the art of ore-dressing, and by reason of problems incidental to the peculiarities of the new ores being treated. Design and construction progress has likewise been orderly and without radical departure from less recent practice; new features in primary and secondary equipment being logical developments to provide for special conditions to keep abreast of improve¬ments in accessory apparatus. The new plants are being rapidly brought in without hazardous novelties and for the purpose of yielding the principal ingredient, copper, in as large a volume as it will he possible to market; the old United States procedure. In the meantime the domestic plants are shut down or operating at a very low capacity, threatened with untimely demise unless the metallurgist can extract and develop other valuable products from the ores. International agreements .and tariff protection may be a temporary reviving stimulant, but for many mines the days of profit will be numbered unless the ores can be made to yield as values the ingredients now being discarded. Invisible progress in this direction has been made during the past year, and it is to he hoped that time will prove that the outstanding progress of 1931 was in the development of processes for the ultimate recovery of by-products from copper ores, perhaps even relegating the value of the copper yield to secondary importance.

Jan 1, 1932

By A Melloy, D Holt, M Jurak

Oaky North is AustraliaÆs highest producing underground coal mine. In 2011, the mine produced 8.7 Mt of high-quality coking coal. The high quantities are a result of the constant strive for optimising the operating time of major production units, which involves investing numerous resources, including diesel equipment, in supporting and maintaining their operation.In July 2011 it was identified that the diesel particulate matter (DPM) levels in the underground workings were above acceptable levels, due to the high level of diesel activity. Over the next 12 months, several controls were implemented to reduce exposure to personnel: the main ventilation system was upgraded; the production forecast was adjusted to better manage the diesel fleet, removing surges in diesel usage; and an electronic diesel tag board was introduced to centrally manage the distribution of diesel usage around the mine.From the start of the campaign in emission reduction, an intense DPM monitoring regime was established. Within a few months of the introduction of the centralised tag board, there was a major reduction in emission levels. After the installation and commissioning of the new main fans, the emission levels dropped further, such that over-exposures are now a rarity.Oaky North continues to explore new systems to better utilise their diesel fleet while still maintaining control over DPM emissions.CITATION:Melloy, A, Holt, D and Jurak, M, 2013. Reduction in diesel particulate matter at Oaky North, in Proceedings The Australian Mine Ventilation Conference , pp 187-190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By E. Asselin, G. K. Yue

"In the present study, electrochemical measurements, especially cathodic potentiodynamic polarization (CPC) and cyclic potentiodynamic polarization (CPP), have been employed to study the kinetics of ferric reduction on chalcopyrite in aqueous Fe(II)Fe( III)H2SO4 solution at 90 °C and 110 °C. Results from the calculation of speciation in the above solution reveal that, at both 90 °C and 110 °C, the real Fe3+/Fe2+ ratio is much lower than the nominal ratio, which leads to smaller VALUES (for the reversible potential of the ferric/ferrous couple. Exchange current densities of the ferric/ferrous couple were obtained and are on the order of 106 10 5 A/cm2 a t 9 0 °C and 1 07 10 6 A/cm2 at 110 °C, respectively. The Tafel slopes from the CPP method are higher than those from the CPC method at both 90 °C and 110 °C. The transfer coefficients were about 0.360.59 at 90 °C and 0.370.65 at 110 °C. Based on the exchange current densities obtained, the rate constant kc was calculated. It was found that kc at 90 °C was slightly larger than at 110 °C, especially for the results obtained by the CPC method. The average rate constants are 862.17 cm/s for CPC and 65.30 cm/s for CPP at 90 °C, and 477.69 cm/s for CPC and 63.53 cm/s for CPP at 110 °C for nominal Fe3+/Fe2+ ratios ranging from 1:1 to 1000:1. INTRODUCTIONChalcopyrite is one of the most abundant copper-bearing minerals, accounting for approximately 70% of the world’s known copper reserves (Wang, 2005). Most of the currently proposed leaching processes are based on sulfuric acid with ferric ions and/or dissolved oxygen as oxidants. Some of these processes have been piloted in attempts to implement these technologies on an industrial scale, such as Activox (U.S. 5,232,491, 1993), Nenatech (U.S. 5,993,635, 1999), Dynatec (U.S. 5,730,776, 1998), AAC/UBC (U.S. 6,503,293, 2003), Total Pressure Oxidation (U.S. 5,698,170, 1997), CESL (U.S. 5,874,055, 1999) and Galvanox (U.S. 7,846,233, 2010).To date, much effort has been devoted to understanding the kinetics and mechanisms of the oxidative processes (Biegler & Horne, 1985; Córdoba, Muñoz, Blázquez, González, & Ballester, 2008, 2009; Ghahremaninezhad, Asselin, & Dixon, 2010; Hirato, Majima, & Awakura, 1987; Hiroyoshi, Kuroiwa, Miki, Tsunekawa, & Hirajima, 2004; Warren, Wadsworth, & El-raghy, 1982) or the cathode reduction reactions of chalcopyrite itself (Arce & González, 2002; Biegler & Swift, 1976; Biegler, 1977; Nava, González, Leinen, & Ramos-Barrado, 2008), by chemical or electrochemical methods. However, as the most important cathodic processes in chalcopyrite leaching systems, the cathodic reductions of ferric ions or dissolved oxygen are worth measuring due to their effects on the overall leaching rate, as predicted by mixed potential theory."

Jan 1, 2012

By Shengqin Zhang, Yousef Mohassab, Feng Chen, Hong Yong Sohn, Mohamed Elzohiery, Amr Abdelghany

A novel ironmaking process is under development at the University of Utah aimed at producing iron directly from iron oxide concentrate in a flash reactor. This process will reduce hazardous emissions and save energy. The kinetics of magnetite reduction with hydrogen was previously investigated in our laboratory in the temperature range 1150 to 1400 oC at large temperature increments (~100 oC increments). Due to the significant melting that occurs above 1350 oC, the reduction kinetics was measured and analyzed in two distinct temperature ranges of 1150 to 1350 oC and 1350 to 1600 oC (~50 oC increments). Experiments were performed using magnetite concentrate particles of different sizes under various hydrogen partial pressures and residence times. Reduction degrees of more than 90 % were achieved in a few seconds at temperatures as low as 1250 ºC. Different rate expressions were needed to obtain reliable agreement with experimental data.

Jan 1, 2016

By Margaret E. Harris

The formation of nitrogen oxides, the decay of carbon monoxide, and the concentrations of residual hydrocarbons in the secondary combustion zones of propane-air and methane-air flames were studied in three enclosed burners designed to simulate gas appliances such as space and water heaters. The effect of thermally or chemically perturbing the combustion gases above these flames was determined theoretically and by means of factorial experiments. The concentrations of air pollutants and the flame temperatures were measured, and the effects of ingress of secondary air into the primary and secondary combustion zones, flame stability, burner port surface, and simulated recycling of combustion gases were noted. Based on this study, four principles were derived that, applied to gas appliance design, will insure minimal emissions of these air pollutants: 1. Oxides of nitrogen can best be kept low by depressing peak temperatures to about 3,050° F. 2. If this is not possible, then the secondary combustion zone should be cooled rapidly to this temperature. 3. Carbon monoxide concentrations can be limited by rapid induction of secondary air. 4. Hydrocarbon concentrations can be controlled by designing for well-seated, stable flames. In addition, empirical reaction rates were derived that predict the concentrations of nitrogen oxides and carbon monoxide in the primary and secondary combustion zones.

Jan 1, 1970

By S. D. F. Rocha1, L. Katsarou, G. P. Demopoulos

"Crystalline scorodite (FeAsO4·2H2O) has been pointed out as the most stable compound to immobilize arsenic for disposal due to its good stability performance according to EPA’s TCLP test. However, in anaerobic conditions, arsenic releasing is increased to undesired levels due to scorodite reductive break down, in eh <100 mV at 5.5< pH <7 which causes contamination of groundwater. In this work, the concept of encapsulation by controlled deposition of mineral coatings immune to pH or redox potential variations is presented. Aluminum and calcium phosphates were evaluated as coatings and the release of arsenic from scorodite previously coated with phosphates was substantially decreased when compared to the VALUES (obtained from crude scorodite, both in oxic and anoxic conditions. INTRODUCTIONThe widely acknowledged hazardous properties of arsenic as a soil and natural water contaminant and its adverse health effects when present in drinking water have led to very strict environmental regulations (Mandal & Suzuki, 2002) aiming at the drastic reduction of the presence of arsenic in the effluents of the mining and metallurgical industries.In Canada, the Metal Mining Effluent Regulations (Government of Canada, 2002) dictate that the maximum monthly mean concentration in tailings for arsenic must be lower than 0.5 mg/L. At the same time the new Environmental Protection Agency’s (EPA) standard for drinking water foresees concentrations of arsenic less than 0.01 mg/L, which means that the leachability limit for the industrial waste is set at 1 mg/L arsenic (EPA, 1994; Le Berre et. al, 2007). One of the preoccupations of the mining and metallurgical industries is directed to the elimination of arsenic presence in all its effluents, especially since arsenic is commonly found in many ores mainly in the form of oxides and sulphides. After processing of arsenic-containing ores and concentrates, arsenic can be present either in solid residues and tailings, liquid effluents or in flue dusts. Several of these forms of arsenic waste materials are soluble and therefore may cause the contamination of ground water, if disposed of without further treatment."

Jan 1, 2012

By Guohua Bai, Mingjun Rao, Jianchen Lim, Guanghui Li, Tao Jiang

"By using thermogravimetry, optical microscope and chemical phase analysis, the solid-state reduction of carbon-burdened chromite pellets in the absence and presence of additives were investigated. The effects of reduction temperature, reduction time and additives on the metallization of chromite pellet were studied. The results indicate that the pre-reduction ratio of carbon-burdened chromite pellets is improved with the increase of reduction temperature and the addition of additives. The metallization of chromium is increased from 63.9% to 92.8% at 1300 °C for 4h with the addition of 2 wt.% of sodium borate. Investigation suggests that the reduction of carbon-burdened chromite pellets is diffusion controlled. The apparent activation energy without additive is 192.1 kJ/mol, while it decreases to 170.4 kJ/mol in the present sodium borate.IntroductionFerrochrome is used to produce high strength, corrosion resistant, wear-resisting, high temperature resistant and oxidation resistant special steels, and it is becoming one of the most important alloy materials for the production of stainless and high alloying ferritic steels [1-5]. Demand for ferrochrome is steadily on the rise due to the growth of stainless steel industry. Nowadays, more than 80% of the world's ferrochrome is utilized in the production of stainless steel [6-7].Ferrochrome is mainly produced in submerged-arc furnaces (SAF) with chromite lump ore. However, lump ore merely accounts for 20% of the chromite ore output, while fine ore (< 8 mm) accounts for about 80% [8]. Therefore, agglomeration of chromite fine ore is necessary before charging into SAF."

Jan 1, 2011

By Oscar Jaime Restrepo, Juan Camilo Restrepo, Jorge Ivan Tóbon

Portland cement is obtained by a conventional synthesis process from a mixture of limestone and clay at high temperature (1450 °C). This work reports the possibility to obtain cement silicates via alternative methods like Solution Combustion Synthesis (SCS), which optimize both time and temperature, and the consequences to energy efficiency and mitigation of CO2 emissions. The production of one ton of cement emits between 0.62 and 0.97 tons of CO2 into the atmosphere. In this process the CO2 emissions are between 21 and 59%. The combustion methods are chemical redox processes in which, at high temperature, a self-sustaining and fast wave is generated from using chemical precursors and organic fuels.

Jan 1, 2016

By Jean-Pierre Birat, Ana-Maria Iosif, Denis Ablitzer, Olivier Mirgaux

"Integrating environmental considerations into the product traditional process design is now the major challenge for steel industry. Life Cycle Assessment (LCA) is nowadays considered as an appropriate method for assessing environmental impact and selecting new technologies to reduce CO2 emissions for steel industry.In this paper we propose a new methodological concept which combines LCA thinking with process simulation software in order to carry out the life cycle inventory of classical steelmaking process.Using Aspen PlusTM software, a physicochemical model has been developed for the integrated steelmaking route. This model gives the possibility to carry out life cycle inventories for different operational practices in order to optimise the use of energy, to calculate CO2 and other emissions and to control the mass and the heat balances of processes.It is also shown that such approach can be used to design and assess new technologies for steelmaking without large industrial application.IntroductionDuring recent years, it was recognised that CO2 emissions are the major factor of the global warming effect. In order to meet Kyoto requirements, the steel industry is embracing the challenge of sustainable development by improving its competitiveness and economic success while reducing its environmental impacts. Integrating environmental considerations into the traditional product design process, for powerful eco-efficiency, is now one of the major priorities for steelmakers.The European Steel Industry has measured up to this challenge by creating ULCOS (Ultra Low CO2 Steelmaking) consortium that has taken up the mission to develop breakthrough steelmaking process with the potential to reduce CO2 emissions (Eurofer, 2005). In order to develop technologies to reduce emissions, it is necessary to assess the environmental impact of the classical steelmaking route (coke plant, sinter plant, blast furnace, basic oxygen furnace, continuous casting and hot rolling)."

Jan 1, 2009

By Binxu Zhaug, Mark Jolly, Xiaojun Dai

"In conventional investment casting process of aluminium alloys for the application of the aerospace industry, to assure the quality of the final casting, usually the foundry uses large runner system which results in low yield, high energy consumption and high GHGs emission. In one case of this investigation, the yield is between 5 ~ 10% which means that the current casting process wastes large amount of energy and generates lots of scraps. By applying a new casting method, the bulky runner system and the melting/holding time are significantly reduced, the quality of the casting is improved, and in the meantime the related energy consumption and GHGs emission are significantly decreased. In the investigation, the energy efficiencies and GHGs emission between the current and traditional processes are calculated and compared.1. IntroductionAs one of the conventional casting process, Investment Casting Process (ICP) and its applications can be traced to thousand years ago [l]. In current casting industry, ICP still plays an important role in the production of small and precious castings with high quality requirements in automobile and aerospace industries. Both casting quality and manufacturing costs which mainly consist of energy costs have crucial effects on the competitiveness of castings in the market. In the production of aluminium alloy castings using ICP, the energy cost and energy efficiency of a casting facility depend mainly on the efficiency of its melting and heat treating performance. In association with the two performances, more than 60 % of the total process energy costs are symbolised in a typical casting facility [2]. Additionally, in conventional ICP of aluminium alloys for the application of the aerospace, to assure the quality of the final casting, typically the foundry uses huge runner system including big risers/feeders which cause low yield, creates lots of scraps and generates high energy consumption. Consequently, there are huge opportunities for casting industry to choose the best practices for potential energy saving. Furthermore, the reasons such as the stringent limitation of environmental legislation in Europe and the pressure of the rising energy price force the casting industry to reduce the energy consumption and greenhouse gases (GHGs) em1ss10n."

Jan 1, 2012