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By Cang Daqiang, Bai Hao, Li Ning, Liu Xueting, Lu Xin, Zhao Lihua, Li Hongxu, Wei Wei

"Based on the principle of carbon balance, a model was built to calculate C02 emissions of each process and correspondingly the total course of production in iron and steel making. The data from a typical integrated steelworks in China was applied in the model. The results show that the BF and coking process account for the most emissions. Generally, C02 emissions in integrated steelworks depend on three factors, resources utilization efficiency, energy utilization efficiency and energy consumption structure, which were considered in an equation in this paper. Especially, General Emission Factor (GEF) was proposed to assess the relationship between C02 emissions and energy consumption. The results show that, higher GEF will result in more C02 emissions with the same energy consumption and in iron and steel making, the optimization of energy structure and development of eco-industrial park both have significant benefit on the carbon reduction.IntroductionThe Global Warming resulting from the increase of Greenhouse Gases (GHGs), especially C02, in the atmosphere has become the main reason of global climate change, and the carbon reduction is one of the most important ways for the sustainable development [1]. The iron and steel making is a manufacturing industry based on iron-coal high temperature chemical process, in which plenty of C02 is emitted. According to the data from IPCC (Intergovernmental Panel on Climate Change) in 2001, iron and steel making emitted about 650 million tons ofC02 every year, which is the fourth largest industry of the fossil energy consumption [2]. According to the data from EEA (European Enviromnent Agency) in 2006, iron and steel making is the largest source ofC02 emissions, which accounted for about 18% of the total C02 emissions in European manufacturing industry [3].It is estimated that the application of various well developed energy-saving technology, such as Coke Dry Quenching (CDQ), Top Pressure Recovery Turbine (TRT) and Coal Moisture Control (CMC), can make the C02 emissions reduced by 0.5%-3% in iron and steel making, and the further C02 emissions reduction can be achieved if more new energy saving technology is applied, such as sintering plant heat recovery, electricity generation with steam generated from converter and the various by-products gas and the hydrogen making process from COG[4,5]. In addition, the application of membrane separation technology is well expected in iron and steel making [6]. For example, the application of C02 Capture and Storage (CCS) in blast furnace combined with the Pure Oxygen Top Gas Recycled BF (TGRBF) technology can reduce the C02 ennss10ns greatly by about 50%-60% [4].That is, as a kind of C02 end-treatment technology, CCS applied with other technology of C02 recovery would be more meaningful. Actually, reduction of the C02 emissions by changing the structure of energy consumption and raw materials with new process of iron and steel making, such as direct reduction process or smelting reduction process [4,7,8], is the trend of ferrous metallurgical engineering, which is regarded as a kind of source-treatment technology. In this sense, source-treatment technology is more pivotal for the solution of carbon reduction in the future than the current popular energy saving technology. Hence, it is necessary to build the C02 emissions model based on the iron and steel making process and evaluate the relationship between the energy saving and C02 emission reduction."

Jan 1, 2012

By Run-sheng xu, Hai-yang WANG, Di ZHAO, Teng-fei SONG, Jian-Liang Zhang

This paper was mainly focused on the different semi-cokes and charcoal which could be new fuels for blast furnace injection. Through the comparative study with bituminous coal and anthracite coal, the properties of semi-cokes and charcoal were presented in this research. 10 indexes of different fuels were obtained by different standard experiment, including proximate analysis, ultimate analysis, igniting point, explosivity, transportation characteristic, ash properties, grindability, calorific value, combustibility and reactivity with CO2. According to the data analysis, it provided a theoretical basis for rational utilization of various blast furnace fuels, and helped to broaden the scope of the blast furnace injection fuels. This research could contribute to energy conservation, emissions reduction, and sustainable development of iron and steel enterprises.

Jan 1, 2015

By Qiang Zhong, Qian Li, Yongbin Yang, Tao Jiang

Thermogravimetric analysis (TGA) has been used to research the pyrolysis and combustion processes of coal used in rotary kiln of iron ore oxide pellet. Furthermore, the effects of air flow and oxygen concentration on the combustion behavior of coal were examined with TGA. The results showed that two individual stages can be distinguished for the pyrolysis of coal, the water evaporation stage and the de-volatilization stage. And the information on ignition and burnout characteristics can be obtained from the combustion process analyzed by TGA. Large air flow almost has no effect to the combustion process except that it enhances combustion intensity. However, the combustion process is further accelerated under oxygen-enriched conditions. With all experimental results, it could provide an attractive approach of analyzing coal for the rotary kiln process.

Jan 1, 2016

By Jean P. Murray

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

Jan 1, 1999

By G. W. Barton

Process Systems Engineering (PSE) can be defined as the integrated usage of computer-based design and analysis tools. As such, PSE is becoming increasingly important in the chemical and petrochemical industries. This paper shows how a range of PSE techniques have been applied to the zinc electrowinning process. Topics discussed include model development, parameter estimation, steady-state and dynamic model applications, steady-state optimisation and neural network modelling.

Jan 1, 1994

By I. Gaballah

Decontamination of synthetic solutions of copper acetate, chloride, nitrate and sulfate containing 10, 100 and 1000 ppm of copper, using chemically treated barks has been studied. Metal percent removal from solutions depends on the pH and the initial concentration and to some extent on the salt used. It varies from 40 to 99 % of the solution initial metallic ion's content. The maximum retention capacity of the treated bark varies from 31 to 43 mg of Cu per gram of dry modified bark. Bark loaded with copper had been analysed by Scanning Electron Microscopy and lnfra Red spectroscopy. Cu is uniformally distributed in the bulk of the bark. No copper segregation is observed. It seems that copper is bound to the acidic sites of the bark. Anions are not detected on the copper loaded bark neither with the SEM or with the IR spectroscopy.

Jan 1, 1993

By T. E. Warner

In order to detect arsenic and antimony in zinc, various electrochemcial experiments were performed involving the electrochemical introduction of sodium atoms into molten zinc using a solid electrolyte. Under high rates, the formation of the intermetallic phase NaZn13 was assumed to form. Under more moderate injection rates of sodium, employing a symmetric "zinc/zinc cell", a qualitative relationship between the current generated during cyclic voltammeuy and the arsenic and antimony concentrations in molten zinc was observed.

Jan 1, 1999

By P. J. Uggowitzer, H. Kaufmann

"New Rheocasting is a novel route of semi-solid casting, in which the globular semi-solid precursor material is produced by controlled cooling of only slightly superheated melts in conventional steel crucibles. The resulting semi-solid slugs are placed into the sleeve of a vertical Squeeze Casting Machine and then filled into steel dies. Solidification occurs under hydraulic pressures up to 100 MPa Due to the reduced cost of precursor material, reduced investment cost and easier recycling, the New Rheocasting process offers cost reductions of up to 25% over conventional semi-solid casting · routes. The New Rheocast products are pore free, pressure tight, weldable and heat treatable castings.In the present work the New Rheocasting Process is introduced and the influence of heat treatment on mechanical properties of the New Rheocast alloy A356 is discussed.The alloy A356 is cast under ideal New Rheocasting conditions into a step die on an UBE HVSC 350 Squeeze Casting machine. As-east, TS and T6 heat treatment conditions with variations in solutionizing and aging time/temperature parameters are applied and the samples are tested by tensile testing. Alternatively, the same heat treatment conditions are applied to conventional Squeeze Casting parts and compared with New Rheocasting.Questions of potential cost savings due to modified heat treatment conditions are also addressed in this paper."

Jan 1, 2000

By Daguang Lu

The section of sintering and BF (blast furnace) is very important in iron-making process. In practice, the scheduling is so extensive that three faults unfavorable to continuous product will be easier to happen. This paper introduces the integration Petri Net and GA (genetic algorithm) as suitable tools for simulation and optimization of scheduling to section of sintering- BF under a certain hot iron or-der. The situation of the iron plant Chongqing Iron and Steel Company is researched in approach above mentioned. By analysis, the conclusion is drawn that scheduling with optimized values can maintain continuity of key operations , can satisfy order of hot iron in maximal degree and can keep the best stability of key storages.

Jan 1, 2009

By G. B. Harris

Jaguar Nickel Inc. is developing the Sechol Nickel-Cobalt Laterite Project in Guatemala, Central America. Recognizing the potential advantages offered by chloride brine chemistry, Jaguar, at the facilities of Process Research ORTECH Inc, Mississauga, has developed an Atmospheric Chloride Leaching Process using a mixed chloride lixiviant to recover the nickel and cobalt, whilst leaving the majority of the iron and magnesium in the leach residue. Subsequent solution purification and mixed nickel/cobalt hydroxide product recovery is by standard precipitation methods, using recycled caustic magnesia, with a final stage of pyrohydrolysis of a portion of the concentrated magnesium chloride brine for recycling both the caustic magnesia and chloride lixiviant. The flowsheet that has been developed also offers opportunities for by-product recovery and efficient, environmentally clean process effluent management. The paper discusses some of the early leaching results in the context of strong chloride brine chemistry, with emphasis on how the controlling of water activity, hydrogen ion activity and chloride concentration permits the selective leaching of nickel and cobalt from an iron-magnesium matrix. Keywords: nickel, cobalt, iron, magnesium, Sechol, Guatemala, chloride, pyrohydrolysis

Jan 1, 2004

By Xiaodi Huang, Matthew Andriese, Zheng Zhang, Jiann-Yang Hwang, Zhiwei Peng

"The thermal decomposition and regeneration behaviors of wüstite were investigated by in situ high temperature X-ray diffraction (HT-XRD) under non-isothermal condition at heating rate of 4 K min-1 in vacuum ranging from 294 K to 973 K. Wüstite on heating decomposes to magnetite and iron up to 823 K, above which it exhibits marked tendency to regenerate. Investigation of thermal stability of the reaction system shows that the decomposition proceeds under kinetic reaction control while the regeneration is under thermodynamic control. Kinetics study based on the Coats-Redfern integral approximation method indicates that the decomposition reaction follows a Komatsu-Uemura model-based diffusion-controlled kinetics with activation energy of 32.860 kJ mol-1. The thermodynamics analysis of regeneration reaction demonstrates that wüstite regenerates at lower temperature than stoichiometric ferrous oxide.IntroductionOwing to its importance in preparing various magnetic ceramic/metal nanocompostites or nanocrystals with high values of coercivity for the application as recording media, wüstite (non-stoichiometric ferrous oxide) has been attracting the attention of scientists over a long period [1-6]. The thermal behavior of wüstite was investigated by several researchers and phase transformations due to thermal decomposition and regeneration of wüstite during the heating in a specific temperature range was observed [7-9]. In spite of wüstite being found to dissociate to magnetite and iron at temperatures lower than 848 K and then regenerates at higher temperature, a clear understanding of the reaction mechanisms is clearly lacking [9]."

Jan 1, 2012

By Baozhong Ma, Yonggang Wei, Shiwei Zhou, Bo Li, Chengyan Wang, Hua Wang

The effects of additives with Na2S, Na2SO4 and CaSO4 on phase transformation of nickel laterite ore in low-temperature reduction roasting process using carbon monoxide were investigated. The results showed that diffraction peaks of forsterite increased with increasing reduction temperature for 30min with the addition of 10wt% Na2SO4 and 50vol% CO, and diffraction peaks of forsterite increased with increasing the content of Na2SO4 at 900°C for 30min. Comparing the above three additives, phase transformation of nickel laterite ore were strongly influenced with the addition of 10 wt% Na2SO4 and 10 wt% Na2S. Calcium sulphide from the thermal decomposition of CaSO4 was carried out in the reaction product. SEM-EDS analysis result deduced that increasing the dosage of Na2SO4 from 10wt% to 15wt% could promote the polymerization of ferronickel and improve the grade of nickel in ferronickel.

Jan 1, 2015

By Kimio Itagaki

The distribution behaviours of the VA elements between the gas, slag and matte phases in copper smelting were evaluated on the basis of the thermodynamic data, most of which were determined by the authors. The distribution is basically dependent on the process factors such as temperature, the content of the element in charge, the amount of the waste gas and degree of vapour saturation with the elements. The thermodynamic quantities such as the activity coefficients of the VA elements in matte, the activities of iron and copper, SO2 or 02 potential and the distribution ratio of the elements between the slag and matte phases seriously affect the distribution, and the behaviours in various smelters could be explained systematically and reasonably by considering the changes in these quantities, In oxidation smelting at PSO2= 0.1 to 1 atm, the proportion of arsenic and bismuth in gas is predomi22t for the arsenic and bismuth distributions in both smelting and converting stages. The degree of vapour saturation has serious effect on the distribution, and sufficient contact between gas and matte phases is desirable for transferring arsenic and bismuth into gas phase.The elimination of antimony by means of vaporization is not significant. In reduction smelting at po2 = 10-11 atm, the proportions of arsenic and antimony in the gas phase are quite small, but the proportion of bismuth does not change significantly.

Jan 1, 1983

By J. W. Ahlrichs

In gold exploration and metallurgical testing, the role of the mineralogist is to assist in solving problems with regard to (a) sampling, (b) gold occurrences, and (c) petrologic classifications of host rocks. The presence of "coarse" gold as a sampling problem can be overcome by various methods, including "screen fire assays," screened analyses and special gravity techniques which may be used to determine distributions of "coarse" versus fine gold. Determinations of mineralogic associations of gold usually require special separation techniques, accompanied by fire-AA-mineralogic assays of the products. After accurate mineralogic analyses are obtained for various products, quantitative distributions of refractory gold associations can be calculated by the use of simultaneous equations. Petrologic classifications are required by the geologist for mapping and interpretation of the various rocks. After the petrology and mineralogic differences of the rock units are determined, x-ray diffraction analyses of analytical pulps can be used for lithologic logging of drill cores. XRD logging is an efficient method for correlating lithologic units and alteration trends throughout a gold prospect.

Jan 1, 1981

By Ryokichi Shimpo, Akio Fuwa

"The process-measurements of copper smelters in Japan were investigated for the summary of the latest technique and for the fundamental study of process control. The smelters investigated are those employing flash smelting furnace and P.S. converter, one reverberatory furnace and P.S. converter, and one continuous smelting converting furnace (M.I. process). Respective process is then considered, consisted of several reactors of different functions. The measurement methods were summarized in each reactor, including the measurement points. The methods of chemical analyses of the samples in each reactor were also investigated.IntroductionAn investigation on the process measurements, chemical analyses, and system control in copper smelters in Japan were carried out for understanding and summarizing the technique of the pyrometallurgical copper smelting operations. The typical seven processes in six copper smelters were investigated in the period from 1985 to 1987. The smelters investigated were Touyo Smelter of Sumitomo Metal Mining Co., Ltd., Kosaka Smelter of Dowa Mining Co., Ltd., Saganoseki Smelter of Nippon Mining Co., Ltd., Tamano Smelter of Hibi Kyodo Smelting Co., Ltd., Ashio Smelter of Furukawa Co., Ltd. and Naoshima Smelter of Mitsubishi Metal Co., Ltd. They include five flash smelting furnace and P.S. converter systems, one Mitsubishi continuous smelting and converting process (M.I. process), and one reverberatory furnace and P.S. converter system.The investigation was performed by making inquiries about the measurements, chemical analyses, system control, and their future prospects to the engineers in each smelter and by summarizing up in each item. The system control and future prospects were summarized in another paper titled ""Process Control Scheme of Copper Smelting Processes in Japan and Future View."

Jan 1, 1989

By Jinliang Zhang, Jian Pan, Deqing Zhu

"Limestone and burnt magnesite were added to vary MgO content and basicity (CaO/SiO2 ratio) of pellets for investigating their influences on the properties of specularite pellets. At fixed MgO content, the addition of limestone does not affect on the properties of green balls significantly. The addition of burnt magnesite has obvious influence on the quality of green balls, especially on the thermal shock temperature. Without burnt magnesite, the thermal shock temperatures are about 400°C, and, the thermal shock temperature increases to 600~630°C by adding burnt magnesite. For preheated pellets, when the burnt magnesite is added, the compressive strength will be decreased. For roasted pellets without burnt magnesite, the calcium additives can form binding phase of calcium-ferrite, and suitable liquid phase will improve recrystallization of hematite, but excessive liquid will destroy the structure of pellets, so the compressive strength of pellet increases firstly and then decreases. When adding burnt magnesite, the compressive strength will increase as the basicity increases. When the basicity is more than 0.2, the compressive strength of the pellets various MgO content and basicity is above 2500N/pellet and then MgO-bearing fluxes can be added to prepare pellets with good high temperature properties.IntroductionWith the rapid development of the steel industry in China, oxidized pellets, possessing good mechanical and metallurgical properties, are becoming indispensable burdens for blast furnace ironmaking [1-3]. However, this has resulted in the shortage of domestic iron concentrates, so many Chinese steel plants begin to use imported hematite concentrate to prepare pellets. Compared with magnetite pellets, the hematite pellets require high roasting temperature and narrow roasting temperature range (1300–1350°C) and possess low compressive strength [4,5].1"

Jan 1, 2012

By C. P. Snyman

Three independent methods of coal classification can be distinguished, namely on the basis of grade, type and rank. The latter two can be determined accurately and unambiguously only by means of microscopical techniques. These three independent variables affect all the coal properties and therefore also the technological behaviour of a particular coal. The influence of the inorganic constituents of coal on the fusibility of the ash and on the length of the slag, and also on fouling and slagging, is discussed. The fractionation of the ash-forming constituents during combustion and gasification of pulverised coal shows that fouling and slagging are not related directly to the fusibility and composition of ash of the coal as a whole. The results of combustion experiments using a drop furnace technique indicate that the ignition temperatures of the light volatiles in the coal, and of the formed char, as well as the burn-out time of the char are more dependent on the rank than on the type or grade of the original coal. High-ash coals, however, apparently ignite at lower temperatures and are more reactive than low-ash coals of similar type and rank. The surface properties of coal, which are important in froth flotation and oil agglomeration, correlate well with the inherent moisture content (and by inference with the heat of wetting and the calorific value) and therefore with the type and rank of the coal. In coal exploration, variations of rank offer the possibility of predicting the presence of an intrusion near the seam, thus contributing to more effective exploration and mine planning.

Jan 1, 1991

By Joseph Goodwill

1. PURPOSE The objective of this paper is to summarize a study undertaken by the EPRI Center for Metals Production (CMP). The overall purpose of the study was to identify electrolytic opportunities that might merit consideration for joint development by industry and EPRI. 2. SCOPE The electrolytic technologies of interest to this study include: Electrorefining, Electrowinning, and Fused-salt electrolysis. Recovery from primary, secondary, and waste materials were included in this effort; however, we excluded from consideration: Plating and coating operations, such as electrogalvanizing; Mining and milling operations in which electric energy is predominantly used for comminution; Electrothermal processes in which submerged-arc, open electric-arc, and plasma-based smelting processes use electric energy largely to provide a melting or refining ("heating") capability; and Aluminum electrotechnologies since these were the subject of a separate study (CMP 86-2). We recognize that there may be some "gray areas" between these excluded areas and the electrolytic sectors of interest. For this reason, a secondary criterium was used, namely, if the major use of electric energy was to extract or refine the

Jan 1, 1990

By J. E. Dutrizac

The mineral forms of silver, lead and cadmium in the zinc concentrates and the various roaster products made by the Kidd Creek Division of Falconbridge Inc. have been elucidated. In the concentrates, all three elements occur mainly in sulphide form, either in solid solution in the principal ore minerals or as discrete mineral grains. During roasting, Ag, Pb and Cd are preferentially concentrated in the hot cyclone and ESP dusts of the roaster train. Silver is converted to <0.5 µm grains of silver metal and to Ag2S04 which dissolves in or impregnates silicates. Lead is converted to Pb-bearing silicates or to PbS04 and PbO which are present either as tiny free grains in ZnO or as an intergrowth with lead silicate. Lead is also a minor constituent of the ferrite phase. Cadmium occurs mostly as cadmium-bearing zno and ZnFe2o4 , but a significant amount also reports as Cd-bearing silicates or zinc sulphate.

Jan 1, 1990

By Yongzhong Xiao, Tiejun Chun, Jian Pan, Zhen He, Deqing Zhu

"In this paper, the reduction kinetics of low grade hematite ore was calculated. Mineralogy shows that the ROM (run of mine) ore is of low grade hematite ore type, assaying 27.2 wt% Fetotal and with main valuable minerals of hematite. The reduction kinetics shows that the reduction reaction rates of pellets with additive and without additive are all controlled by diffusion through the product layer. The calculated apparent activation energy of pellets with 12 wt% complex additive is 8.55 KJ/mol, dropping 62.23% compared to that of pellets without additive.IntroductionWith the rapid development of iron and steel industry in China, there has been a soaring demand for iron ores in the past decade. The imports of iron ores have increased from 148 million ton in 2003 to 620 million ton in 2010[1]. Therefore, large quantities of low grade iron resources are necessary to utilize in China at the moment. During the past years, extensive research has been carried out on the low grade hematite ores [2-6], such as reverse floatation, gravity separation, high-gradient magnetic separation and direct reduction-magnetic separation. Direct reduction-magnetic separation is an innovation way to treat the low grade hematite [7]. However, the research of reduction kinetics of low grade hematite is few. Some research about the reduction kinetics of reducing iron oxides by CO was studied [8]. The results indicated that the apparent activation energy is 8.0-28 KJ/mol when the reducing reaction is controlled by internal diffusion. The apparent activation energy is 50-75 KJ/mol when the reducing reaction is controlled by chemical reaction. In this paper, the reduction kinetics of pellets was also been studied."

Jan 1, 2012