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By John Wallace, Chib Iheagwara

"Refinements in sensor design have produced low-cost rugged elements to act as loop coupled with stable detection hardware for eddy current measurement in difficult environments. This has allowed direct dimension gauging of nonferrous and ferrous products above the curie point for absolute dimensions and electrical conductivities independently. The software was developed for the analysis of electrical conductivity profiles in CZ silicon crystal growth, then refined for monitoring bar properties and tube properties. Since in most metal working operations, speeds at the minimum of a few hundred feet per minute are encountered the design of the gauge was optimized for a rapid measurement. Independently extracting electrical conductivity provides data in some metal systems for determining the temperature of the monitored product.IntroductionThe primary reason for the use of eddy currents in gauging is that in hostile environments of metal working techniques such as laser gauging and ultrasonics are not always robust enough for in process measurements. Our goal is to use the technique of eddy current measurement as a quantitative control element in various hot and cold processing operations. Inspection in the early stages of metal and semiconductor processing is usually too costly to introduce in a well developed process and these tools are usually only employed in process development. Until recently there has been no efficient general analysis to allow real time measurements in the cylindrical and the probe geometry that could separate dimensional changes from material property changes both which effect the eddy current response. The basis for these measurements is that forward electromagnetic problem for conductors can be solved exactly for the test geometry which allows an inverse analysis to be made by relaxing the dimensions and conductivity to values which reproduce the measured response[!]. This transformation is based on analysis developed in Robert Siegfried' s thesis and was explored both by modeling and by physical measurement. This analysis was extended over the last few years to allow a more compact data set to be used to exact physical properties. The main result was that the technique would work on high ·quality physical data on as little as three test frequencies with the penalty being that the analysis is computational intensive. The main result of this work was that a quantitative inverse analysis of eddy current response would allow a general instrument to be used for a variety of measurements rather than being tailored for a specific measurement on a specific material test geometry. The development of these instruments has progressed over the last ten years for monitoring real time solidification, crystal growth[2] and hot seamless tube forming where the use of standards in traditional eddy current is limiting. The specific instrument design was dictated by the requirements of the algorithm for both frequency selection and levels of systematic noise that could be tolerated. Because the data is need for real time information this dictated that the system be a parallel multifrequency eddy current instrument feeding the same sensor. The sensor have to be simple and robust and usually a single loop or several loop of heat resistant wire or tube. This presentation is about using inversion of multifrequency eddy current data in real time to produce dimensional and property data on cylindrical conductors and planar conductors in real time. The object of the measurements is to produce dimensional outputs on measurements of conducting material without having to establish a detailed standard for each material or size tested. The dimensional measurements using eddy currents is complicated by material variations in conductivity due to temperature and composition. Those variations that are not geometric are often not of critical interest and complicate the measurement. The dimensional changes are often of more importance"

Jan 1, 1997

By Xuling Chen, Yi Wang, Xiaohui Fan

"The current control method of grate-kiln iron ore oxide pellet production is lack of accuracy and normalization due to the limited detection conditions. Therefore, mathematical models of grate-kiln temperature field are presented. With calculation of gas-particle heat transfer as well as enthalpy changes of moisture evaporation and magnetite oxidation, the thermal history of pellets throughout grate-kiln process can be acquired and used for production status estimation. Taking the calculated results as well as detected data in production as inputs, process parameters such as running speed, fan opening and coal injection rate as adjusting objects, expert system for grate-kiln pellet production is outlined. And the preheating section dominated control strategy is explained. Results of production application show that the stability rate of gas temperature in gas hood of preheating section is increased from 91.0% to 94.2%, compressive strength and first grade rate of pellet are increased by 3.62% and 2.36%, respectively, while FeO content is 18.18% lower. Control guidance of this expert system can solve production anomalies effectively, stabilize grate-kiln iron ore oxide pellet production and improve pellet quality.IntroductionSteel industry in China has developed rapidly in recent years. China’s crude steel production in 2010 is nearly 627 million, which is 44.2% of the world total production. Burden with higher quality is demanded by enlargement and modernization of blast furnaces. And oxide pellet production has become a growing concern. In 2010, the total production of pellet in China is 110 million, and about 60% is produced by grate-kiln process."

Jan 1, 2012

By B. Mishra

The major waste product of the alkaline extraction of alumina from bauxite [Bayer Process] is known as red-mud. Approximately, a ton of red-mud is produced for every two tons of bauxite that is mined. The red-mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that over 90 wt. pct. alumina can be recovered from red-mud by soda-ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of over 94 pct. At this stage, the product could be charged through the tuyeres in an iron blast furnace or smelted to produce pig iron. The mineralogical characteristics of the reduced product are not amenable to magnetic separation for iron recovery. The problems associated with the use of reduced red-mud as an alternative to direct-reduced iron [DRI] has also been discussed. Special attention has been paid to lower the alkali content of the reduced material. If smelted, the concentration of titanium oxide in the slag will be significantly high justifying its recovery by an acid-leach process. This paper describes the successful efforts of iron and alumina recovery.

Jan 1, 2000

By Ram Avtar

High tensile thick plates (>80mm, weight ~3000 Kg) of medium carbon low alloy steel, when heat treated, manifested higher percentage of crystalline area (>20%) in fractured surface. Such problem was not encountered in thinner plates. The genesis of higher crystallinity in fracture was examined. It was observed that the thicker plate undergone slower rate (Average 0.9oC/Sec.) from soaking temperature to Ms temperature) of cooling after austenising during oil quenching and thereby quenched microstructure had upper bainites. During tempering of as quenched bainite, additional precipitation took place at the lath boundaries of bainite. This led to weakening of grain boundaries and aided easy crack propagation during fracture and resulted in formation of higher percentage of crystalline area in fractured surface. Enhancement in cooling rate (Average 1.8oC/Sec. from soaking temperature to Ms temperature) of austenised plate by switching over from oil quenching to water quenching practice resulted in complete transformation of austenite into martensite and produced ductile fracture (zero Crystallinity). Plates conformed improvement in mechanical properties between 2-5%.

Jan 1, 2009

By Mitsutaka Hino

The contents of gangue minerals, such as A1203, P205, crystalline water and so forth in the iron ore imported to Japan tend to increase year by year, Though the increments of such gangue contents are approximately 0.1-0.2 mass%, some problems for the blast furnace operation in ironmaking process have already been reported, In order to clarify the mechanism of harmful effect caused by the small increment of gangue minerals, mainly A1203, on the blast furnace operation, the dripping behavior of FetO-CaO-SiO2-AI2O3-MgO slag from the iron funnel, which simulated the micro-porosity in sinter ore, has been observed with the wide range of basicity, Al2O3, FetO and Mgo contents. The effect of MgO on the dripping behavior of slag has been summarized in this paper, It was found that the addition of 2mass% MgO resulted in large increase of hold-up on the most of the conditions. When FetO content was less than 20mass% and the basicity was lower than 0.8, MgO lowered the hold-up even if the slag contained 10mass% Al2O3. Every slag hold-up showed the minimum at the basicity of less than unity on the conditions of constant FetO and A1203 contents. This trend became remarkable when the slag contained 2 mass% MgO.

Jan 1, 2003

By Jack A. Simon

My remarks are directed at relating some of the mineralogical approaches mentioned in the preceding presentations to emerging energy issues. The assembling of this symposium on process mineralogy attests to the growing concern for energy development from the non-petroleum mineral fuels and the unconventional petroleum fuels. A report in 1979, prepared under the auspices of the National Research Council/National Academy, of Sciences, was published in two parts and dealt with "Redistribution of Accessory Elements in Mining and Mineral Processing." This report rather comprehensively considers broad aspects of minerals associated with the solid fuels considered in this symposium and focuses attention on some problems of process mineralogy relative to these fuels. Papers have dealt with coal, oil shale, tar sands, and uranium minerals. Problems associated with mining, processing, and use of these materials have significant differences, but also have some factors in common relative to the subject of this symposium.

Jan 1, 1981

By Carlos A. Nunes

V-AI alloys have been used commercially to produce pure vanadium by Electron Beam Melting (EBM), as well as to obtain Ti-based alloys (ex. Ti-6AI-4V). The aluminothermic reduction of vanadium pentoxide (V205) is the primary method to obtain these alloys. Concerning the obtention of pure vanadium, earlier studies have indicated alloys presenting Al content between 10 and 15wt% as the most suitable alloys for direct EBM. In the present work we investigated the aluminothermic reduction of V205 in order to define process parameters for the obtention of V-AI alloys with composition in the previously mentioned range. It was studied basically the effect of excess AI, CaO addition and reaction atmosphere (air, argon) on the alloy composition (AI, 0, N). In addition, microstructural analysis of selected alloys by SEM (BSE images) and EPMA (WDX) were also performed.

Jan 1, 1996

By J. Alberto Vázquez M.

A sensor employing yttria-stabilized zirconia (YSZ) was used to determine the oxygen activity of molten copper at laboratory scale at temperatures of 1200° and 1300 dc. The reference electrode was a Ni-NiO mixture. The amount of the deoxidizing agent (CU3P) ranged from I to 3% of the mass of copper. Thermodynamic analysis of the Cu-O-P liquid system was carried out to predict the required deoxidizing agent and the final composition of the molten copper. Both results, calculated and experimental, show that the oxygen removal is more efficient at lower temperatures. The kinetics of the deoxidizing reaction is very fast in the first minutes of the treatment. A metalography analysis of rapid cooled samples show the oxygen and phosphorus distribution

Jan 1, 2003

By Yuanbo Zhang

Keywords: Complex Iron Ores, Roasting, Tin, Zinc, Pellets, Comprehensive Recovery. The complex iron ores containing tin, zinc are typical refractory ores. Large reserves of the ores are found in China and have not been utilized efficiently so far. A new process of tin and zinc recovery and pellet preparation from iron concentrate containing tin and zinc by controlled atmosphere roasting is developed in this investigation. The results of 2573 N/P compression strength of product pellets, the 91.49% and 82.22% volatilization of tin and zinc respectively, are achieved for a concentrate containing 0.39% tin and 0.28% zinc. The strength and chemical compositions of the pellets meet the requirement of blast furnace ironmaking. Volatilization mechanism of tin and zinc are investigated. Thermodynamic study shows that the reduction balance curves of SnO2(s) and SnO(g) are proximate in the presence of carbon, and the standard formation free enthalpy of FeO and SnO2 is also approachable. Therefore, it is difficult to realize the complete volatilization of tin in the form of SnO(g) by selective reduction. But SnO2(s) and SnO(g) will form SnCl4(g) or SnCl2(g) in the presence of chlorides and can be easily volatilized from the ores.

Jan 1, 2005

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By Chen Tian, Tingfeng Wu, Qinghai Pang, Junhong Zhang, Zhijun He

Microwave technology as new aided tool has been applied on waste water treatment and metallurgical fields. This paper explores the affected factors such as microwave power, microwave irradiation time, polyaluminium chloride (PAC) amount and addition of phosphoric acid on treatment of Blast Furnace gas washing water by utilization of coagulation associated with microwave. Through the orthogonal experiment, the optimum experimental parameters were obtained in the course of treatment of 300 ml Blast Furnace gas washing wastewater: 396 W microwave power, 2 min of microwave irradiation time, 0.12 ml Added PAC and 0.8 ml added phosphoric acid. It indicates the affected factors in descending order on removal of SS in BF gas’s washing water: Added PAC level, added phosphoric acid level, time of microwave irradiation, and microwave power while those parameters that can affect suspended solids(SS)’s hardness reduction in descending order are added phosphoric acid level, added PAC level, time of microwave irradiation, and microwave power. Also, it demonstrates those parameters that can affect washing water’s turbidity in descending order: Added PAC level, time of microwave irradiation, added phosphoric acid level, and microwave power. The results showed that PAC coagulation associated with microwave on treatment of Blast Furnace gas washing wastewater has several benefits: short treatment time, strong sedimentation velocity and other excellent characteristics, it can effectively remove suspended solids in wastewater, the SS hardness and turbidity can be reduced.

Mar 1, 2017

By Tianzu Yang, Weifeng Liu, Lin Chen, Wei Chen, DUCHAO ZHANG, HUI XIAO

Carbonaceous refractory materials are widely accepted in many reducing smelting processes such as iron and ferroalloys. Oxidizing processes such as copper concentrate smelting traditionally use magnesia and/or alumina/silica refractory materials. The main objection to the use of carbon-based refractories as the exposed working lining in oxidizing applications is the potential for free oxygen to react with the carbon at high temperature, which could rapidly degrade the refractory lining. In 2013, Outotec and GrafTech conducted joint trials of a thermally conductive, carbonaceous lining for smelting copper concentrates in the Outotec® pilot-scale top-submerged-lance (TSL) furnace in Dandenong, Australia. This testwork had two equally important goals; to demonstrate the ability of carbon refractories to withstand oxidizing process conditions, while ensuring that neither furnace operating conditions nor process stability were negatively affected by the refractory material. The paper discusses the input parameters of the trials, key observations during the testwork program, and the results and conclusions from both process and refractory design standpoints.

Jan 1, 2016

By Ian M. Ritchie

Right across the universities of the developed world, the traditional disciplines of physics and chemistry are losing ground. Extractive metallurgy, which depends so heavily on chemistry, is also contracting despite a clear need for people with this kind of training in the mining industry. Reasons for this loss of popularity are discussed in this paper. High on the list is one of image. The extraction of metals is widely seen as a dirty, polluting, sunset industry which involves working in remote and uncomfortable corners of the earth for inadequate compensation. Ways in which the image problem can be overcome are considered. It is concluded that a concerted effort needs to be made by the universities and industry to redress this situation. The importance of extractive metallurgy, both now and in the future, when a greater emphasis will be placed on sustainability and recycling, needs to be stressed. In addition, courses need to incorporate training for a career path that leads on beyond extractive metallurgy.

Jan 1, 2003

By Björn Saxen

Outotec atmospheric Direct Leaching has so far been implemented for zinc production capacities of around 100,000 t/a. Lately, there has been growing interest for small scale direct leaching plants, producing circa 30,000 t/a of Zn. Such small leaching plants can provide extra front-end capacity in existing roaster-based plants and enable treatment of feed materials not suitable for roasting. In small scale plants the proven OKTOP® 9000 Direct Leaching reactors are not readily applicable, due the large size. For smaller installations a modular approach is proposed providing multiple advantages, such as reducing the construction time and amount of the site work required causing less disturbance to regular plant operation with reduced cost. In this paper, we present advantages that can be achieved by using modular OKTOP®C reactors and discuss also process design when connecting a small scale direct leaching process to an existing zinc plant. Also benefits of direct leaching expansion are presented.

By Pengfu Tan

One copper Isasmelt furnace has been operated in Xstrata Copper at Mount Isa in Australia since 1992. A thermodynamic model and computer program, CuModel, has been developed to model the distribution behaviors of Cu, Fe, S, O, Ni, Co, Sn, Pb, Zn, As, Sb, Bi, Au and Ag, copper loss in the slag, and heat balance in copper smelting process, matte converting process and copper continuous smelting process. The thermodynamic model has been used to model the key parameters in the control of the copper Isasmelt furnace. The effects of the process parameters on the control of the copper Isasmelt furnace have been predicted and discussed. These process parameters include SiO2/Fe, matte grade, coal, temperature, spec air of feed, oxygen enrichment, and MgO contents in slag.

Jan 1, 2006

By Cong Wang, Kexin Jiao, Yongan Zhao, Haibin Zuo, Jianliang Zhang

The carbon composite brick is a new refractory used in blast furnace hearth and bottom. It caused wide attention due to its high thermal conductivity and low erosion by molten iron. In this paper, chemical constituents, SEM-EDS and X-ray diffraction were carried out in order to understand reaction mechanisms. A series of experiments of oxidation resistance characteristics were made. The oxidation mechanisms of carbon composite bricks in the presence of air were analyzed. According to the analysis on many experimental results, the oxidation process of carbon composite bricks under different temperatures were controlled by different mechanisms. In the condition of high temperature, SiO2 as oxidation product hindered the diffusion of O2, and reduced the oxidation loss of graphite in the internal.

Jan 1, 2015

By P. Wieser, D. Feke

"Priming of filters with small pores is influenced by the surface tension of the liquid metal and may be complicated by freezing • Freezing followed by melting has been observed experimentally. This process has been modeled on the basis of one dimensional heat flow by radiation to the filter and by conduction in the metal. Also considered are super-heat of the metal and the initial filter temperature. The results of the model provide useful guidelines for the application of filters. IntroductionFiltration has been recognized as a valuable method of refining by removing suspended phases from liquid metals or alloys. Woven fiberglass type fabrics and wire screens were used initially in the aluminum industry. With the introduction of the ceramic filters that exhibit improved inertness and refractoryness, filtration has been introduced to higher melting alloys including cast irons, superalloys, stainless steels, as well as low and medium carbon low alloy steels. A considerable literature is delveloping rapidly on the progress in applications and the advances in understanding the mechanisms and effectiveness of filtration processes (1-8).With the use of filtration for different alloy systems for the production of cast to shape parts a bewildering variety of gating system modifications has been developed (Figure 1) to accommodate the installation of filters in the mold. The modifications have two principal purposes: 1) the runner expansion is intended to compensate for the resistance to flow due to the filter and that of the captured inclusions, and 2) the metal reservoir upstream of the filter, provides a temporary by-pass which permits metal to flow across the filter and heat it until priming can be accomplished. priming of.filters by low and medium carbon steel is readily accomplished but, compared to such alloys as cast iron or 19 Cr-9Ni stainless steel, requires greater precautions to avoid failure to prime by excessive freezing on or inside the filter pores. This problem is further examined below:"

Jan 1, 1986

By Brommerm Tracey, Britt Elin Gihleengen, Elsa Olivetti, Hans Ole Riddervold, Randolph Kirchain, Geir Øyen

"Compositional uncertainty in secondary materials and variable processing conditions inhibits secondary material utilization in the production of aluminum alloys. Efforts to implement optimization models that direct batch planning have limited industrial presence due to factors such as the insensitivity of these optimization models to dynamic plant circumstances. This paper describes a chance constrained model formulation that generates lower cost, robust batch plans with significant flexibility towards changes in processing conditions. The principal attribute of the chance constrained formulation is its inherent mitigation of risk by diversifying the batch plan. This paper compares aluminum remelter batch planning using the chance constrained formulation with a traditional deterministic model and a manual batch planner. With the expectation that volatile material prices, restricted scrap material availability, and pressure by consumers and legislation for increased recycled raw material input will continue in the future, batch planning tools that inherently diversify a production portfolio will become increasingly advantageous for industrial aluminum remelters.IntroductionAluminum remelters must develop strategies to incorporate lower cost secondary materials into finished alloys to remain competitive amidst increasingly demanding market and regulatory conditions. Determining the optimal combination of incoming raw materials to produce an alloy that meets compositional specifications presents remelters with a complex problem that has driven the development of computational tools commonly referred to as batch planning or blending algorithms. The ubiquity of the ingredient or raw material blending problem in production has motivated ongoing development of batch planning algorithms since the classic nut-mix problem in the 1950's [1]. The most common model formulation for industrial aluminum remelters are deterministic, linear optimization programs [2]. These blending problems determine the optimal combination of raw materials by minimizing cost subject to constraints around demand, availability, and compositional specification. Despite extensive research and moderate computational requirements, batch planning algorithms are inconsistently used in industry. Insufficient incorporation of the complexity of real world remelting conditions into these models provides an obstacle for their implementation [3]. For example, many batch planning algorithms do not explicitly incorporate the impact of compositional variation of the raw materials on overall batch cost. Additionally, they do not allow for endogenous specification of tolerance to error in batch planning, so provide little flexibility where a batch planner would like to incorporate materials of greater uncertainty. Incomplete accounting for quality variability undervalues secondary materials leading to overly conservative use [ 4, 5]."

Jan 1, 2011

By W. G. Davenport

H20 is present in many flash furnace inputs. Examples are: (a) moisture in concentrate and flux (b) humidity in blast (c) moisture in hydrocarbon fuel, particularly coal, Appendix IV. H20 may also leak into the furnace from damaged water-cooling jackets. H2O, especially that it be included H2O, exerts a strong cooling effect on the flash furnace. It is important our calculations. As will be seen from the calculations, gaseous and liquid H2O both increase flash furnace industrial oxygen and oil requirements. This is because gaseous H2O (humidity in blast) must be heated from its input temperature to the flash furnace off gas temperature. Liquid H2O must be evaporated and heated.

Jan 1, 2001

By Zhihe Dou, Zimu Zhang, Guozhi Lv, Yan Liu, Xiaoli Jiang

"Cyclic heat stewed slag washing water carries high content of alkali and calcium and may cause serious tube scaling and impose an adverse impact on normal production. This study proposes a solution to utilize washing water by absorbing and mineralizing CO2, potentially restraining scaling and being able to create calcium carbonate powders. Effects of water flux on water quality, utilization ratio of CO2 and yield of calcium carbonate powder have been investigated; meanwhile, features of calcium carbonate powder are also represented. On the other hand, effects of factors such as as injection flux, pressure of CO2 on utilization ratio of CO2, morphology and purity of calcium carbonate are also investigated. The results show unambiguously that after soften injection of CO2, calcium ions were removed effectively via precipitation, alleviating the scaling problem. High purity yet fine carbonate powder could be achieved.IntroductionNowadays, 0.34 tons of blast furnace slags will be produced when producing 1 ton of pig iron; ensuing that, 0.12 tons of steel slag will be generated with 1 ton steel production while 1.57 billion tons of steel output all over the world in the year of 2012. It is therefore a critical issue to realize zero discharge of steel slags to achieve sustainable development and cyclic economy of iron and steel industry. In recent years, research institute of MCC and China JINGYE engineering company developed a heat stewed steel slag self-decomposition technology GENERATION III to solve the problem of instability of steel slags and realize the zero discharge. However, the problem of circulation line scaling which may cause the clogging, even exploding, need to be solved. The principles of the technology are: directly spraying water to the high temperature steel slag when it is poured into the hot closed pot, realizing the selfdecomposition via utilizing the waste heat of steel slag. The washing water is recycled to achieve a cyclic utilization. The process is shown in Figure 1."

Jan 1, 2014