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By Chris P. Pistorius

Over the past few decades the carbon intensity of ironmaking and steelmaking has been reduced considerably through improved efficiency in blast furnace ironmaking, partial replacement of coke with less carbon-intensive fuels, and increased use of scrap and direct-reduced iron in steelmaking. To evaluate possible further reductions in carbon intensity accurate process information is needed. A preliminary test of the fidelity of publicly reported data as a source of process information is reported here. The sources are industry roundups of electric furnace furnace steelmaking and blast furnace ironmaking (published by the Association for Iron and Steelmaking Technology), and data recorded by the Environmental Protection Agency under the US Greenhouse Gas Reporting Program. From a comparison for an integrated steelmaking plant and an electric furnace furnace plant, it appears that the values from the two data sources are consistent. The comparison does rely on process details such as the quantitative relationship between injected oxygen and carbon emissions in electric furnace steelmaking.

By Nagy El-Kaddah, T. T. Natarajan

This paper describes a novel approach for modeling three-dimensional electromagnetically driven flow in inductively stirred systems, and its application to modeling electromagnetic and flow phenomena in sub-mold rotary stirring of billets. It is based on a new T-\jf potential formulation of electromagnetic field, which does not require the calculation of the field in free space. A finite element algorithm has been developed for solving the electromagnetic field and Navier-Stokes equations in the fluid flow domain. The computed results have shown that the electromagnetic force field generates a strong rotational flow within the vertical section covered by the stirrer, and a relatively strong secondary flow beyond the stirrer. It has also been shown that the rotational and secondary flows were driven primarily by the vorticity of the force field at the billet corners. The induced flow in the molten pool was found to be turbulent and the effective mixing region in the molten pool was about three times the length of the stirrer. The mathematical approach presented in this paper provides the theoretical framework for quantifying these effects for any given stirrer configuration and operating parameters.

Jan 1, 1999

By P. Louis

Although cobalt is known and used for its hardness and wear resistance, ductile cobalt can be obtained by electrolysis in chloride solutions, under the following conditions : pH : 1.5 - 2, Co++ : 30 - 60 g/l, current density : 100 - 500 A/m2, temperature 40 - 70°C. No explanation was found for the ductility of the deposit under these conditions. Indeed the ductile P (FCC) cobalt and the hydrogen contents in the cobalt deposits are nearly the same as those obtained in a sulfate media, which gives brittle depo¬sits under equivalent electrolysis conditions. Malleable cobalt sheets can be easily obtained under the proposed conditions which could lead to new applications for cobalt.

Jan 1, 1988

By Minjun Tang, Jianfeng Zhou, Feng Chen, Linjiang Qing, Xiaolei Song, Yufeng Guo, Tao Jiang

"Reduction swellability index (Rsn and low temperature reduction disintegration index (RDI) of vanadium-titanium magnetite oxidized pellets are harmful to the processing of ironmaking, for example, causing serious gas permeability, decreased yield, higher coke ratio and more furnace dust. Thus, the improvements of RSI and RDI of vanadium-titanium magnetite oxidized pellets were investigated in this paper, including the pretreatment of raw material, additives of dolomite or boric acid, pellets treated in chloride solution and so on. The results showed that damp milling as pretreatment and boric acid added in pelletizing were conducive to the RSI which decreased 5% and 7% respectively, while they were not efficient enough in improving RDI. Dolomite was efficient in improving RSI, but had negative effect on RDI. There was no evidence to show that RSI and RDI would be improved when pellets were treated in chloride solution. Pursuing this further, the mechanism of those improvements were investigated.IntroductionIn the world, vanadium-titanium magnetite utilization is investigated around how to recover iron, titanium, vanadium, and divided into blast-furnace method and non-blast-furnace method according to respective characteristics. Blast furnace method [1, 2] can recover iron and vanadium effectively, but Ti02 cannot be recycled. Non-blast-furnace methods include rotary kiln-electric furnace method, pre-reduction electric furnace method, reduction- grinding method and sodium vanadium-rotary kiln-electric furnace method and so on. [3-7]Comparing to the Non-blast-furnace method, the method of blast furnace smelting has been put into industrial applications. And it has the following advantages: First of all, effective recycling iron and vanadium; Second, technical problems of high titanium slag in blast furnace smelting; Third, it has mature technology in blast furnace smelting."

Jan 1, 2013

By Chengyi Ding, Xuewei Lv, Changyang Ji, Rende Zhang, Xiangwei Zheng

Inexpensive and high-quality sinter has an extraordinary position in iron making, and there are many factors influencing the sintering. This research takes the basicity and coal dosage as research subjects to do the experiments based on cost analysis with sinter pot experiment system. Linear program is taken to make the schemes of ore blending. During the experiments of changing basicity from 1.6 to 2.3, the properties and microstructures of the sinter are studied. It comes to a conclusion that increasing the basicity is beneficial to sinter quality but leads to higher cost. To further ascertain the cost of sinter and the potential of saving coke, the work of improving coal dosage is taken on the basis of experiments of changing basicity. Through analyzing the results, a formula (Y=1849+261.1R-130.6C) is proposed which indicates the relation among the cost, basicity and fixed carbon content. And it works well for actual production.

Jan 1, 2015

By Hannu Johto

Boliden Harjavalta has operated a flash smelter for nickel sulphide concentrates in Finland since late 1959. The original nickel flash smelting process was modified in 1995 to a novel nickel matte smelting (DON) with semi-low iron where the batchwise operated converting became obsolete. Since that, the process has been applied to multiple chemically variable nickel sulphide concentrates with high environmental performance. In this paper, the status of the current smelter operations is described together with the recent modernizations of the nickel flash smelting furnace and the slag cleaning furnaces.

By Ping Long, Bin Yang, Jian Wu, Xiumin Chen, Wenli Zhang

In this study, the analysis method of trace element in pure indium using glow discharge mass spectrometry (GD-MS) has been established by correcting the analysis result, which was obtained from non-standard quantitative method of GD-MS. The effect of instrument operating parameters, the resolution and isotopes and the pre-sputtering time on the determination results were investigated respectively. The optimized operating parameters of the instrument were obtained as follows: the discharge current was 37.5mA and discharge airflow was 475ml/min. Mass spectral interferences have been eliminated using selected resolution and isotope. The pre-sputtering time was 30 min. 4 trace elements in two pure samples were determined for 6 times. The RSD were less than 20%. The content of trace elements in indium samples was determined by GD-MS and Chemical Analysis Method of Indium which is tested by inductively coupled plasma atomic emission spectrometry, respectively. The results were consistent with each other.

Jan 1, 2016

By Yuanbo Zhang, Ruijun Wang, Qian Li, Zhao Jing, Guanghui Li, Zhengwei Yu, Chen Liu

The high content of sodium and potassium in sinter is harmful for blast furnace ironmaking. Reductive sintering technology can remove more alkali metals than conventional sintering process. In order to improve the removal ratios of Na and K, reductive sintering with both CO-containing flue gas circulation and carbon-bearing pellet was conducted in this study. Experimental results show that all indexes except the VSV and P were improved in reductive sintering with CO circulation. Flue gas circulation technique combined with carbon-bearing pellets were beneficial to reductive sintering, because it could maintain good sintering indexes and enhance the removal of Na, K. The best removal ratios of Na, K and reduction degree of iron oxides were 20.37%, 63.73% and 23.76%. In reductive finished sinter, silicate mineral becomes the important binder phase, and main iron mineral phases are wustite (FexO) and magnetite (Fe3O4).

Jan 1, 2016

By Taner Kavas

The refractory bricks of a rotary cement furnace containing of alumina and magnesium chromite were studied in order to determine whether they could be used in the concrete production as aggregates. Three mortars were prepared by mixing 1 part cement, 3 part aggregate materials, 0.5 part water by weight and mechanical, chemical, thermomechanical and microstructural characteristics were evaluated. The compressive and bending strength of samples were determined after 2 and 28 days curing. Resistance to chemicals were established by calculating the weight gain of mortars stored in 2 % HCl solution for 1 h and 24 h. Thermomechanical characteristics were determined by measuring the compressive strength of heat treated specimens at temperatures of 400 °C, 600 °C and 800 °C. Consequently, magnesium chromite containing waste brick aggregates have given the best results.

Jan 1, 2006

By Denis Shishin

The pyrometallurgical production and recycling of non-ferrous metals involves the use of complex feed stocks, having awide range of chemical compositions from sources that include mineral sulphide concentrates, high value obsolete materials and process wastes. The commercial viabilities of these operations hinge on the ability to extract value from these materials. Increasingly, modern computer-based tools are used to describe and predict process outcomes, including mass and heat balances, the partitioning of elements and phase equilibria. At the heart of these predictive tools are thermodynamic databases that describe the fundamental chemical properties of a system and all the components present. A comprehensive research program has been established to develop an accurate, self-consistent thermodynamic database describing all gas-slag-matte-metal-speiss-solid phases in the system Cu2O-PbO-ZnO-Al2O3- CaO-MgO-FeO-Fe2O3-SiO2-S-(As-Bi-Sb-Sn-Ag-Au). The database can be used in conjunction with the FactSage computer platform. The accuracy of the database and its application to industrial practice is demonstrated.

By P. M. Tyroler

Inco operates a hydrometallurgical plant to treat the residue from the pressure carbonylation process. The main constituent in the residue is cop¬per. The residue is leached under pressure in an acid sulphate solution in two stages and the copper is recovered via electrowinning. The electrowinning tankhouse is fully integrated into the overall plant flowsheet as spent elect¬rolyte is required in upstream leaching steps. In recent years, the amount of residue had increased and copper removal capacity became the rate limiting factor for the entire plant. Consequently, a major program was undertaken to upgrade the tankhouse with regards to capacity, efficiency, cathode quality, working environment and structual integrity and appearance. This paper will describe current facilities and operation, and detail progress in our up¬grading efforts.

Jan 1, 1987

By Alan P. Prosser

The heap leaching of gold ores by cyanide solution was simulated by computer program. The program uses only basic m1neralogical and chemical data; no process testwork data, such as column leach results, are required. The simulation can be used to forecast the consequences of various changes before and during the testwork, design and operation stages of a particular ore-process system. Also, data about the state of different parts of the heap at various times help create an understanding of what is happening. The effects of mineralogical and process variables on the overall performance of the ?heap leaching process are illustrated. Comparisons are made to column leach tests and production data. The potential of the simulation strategy is discussed for making better use of operating experience and for suggesting specific research objectives. It has become clear that more attention should be paid to other metals that dissolve in the solution.

Jan 1, 1989

By R. W. Bartlett

The extensive central Idaho black sand placer deposits are a potential source of rare earth elements, particularly the heavy rare earth elements that are not prevalent in commercial bastnasite deposits. These placers derive from the Idaho batholith. The geology, occurrence, and extent of these deposits are reviewed and the diverse mineral assemblages and complex mineral chemical compositions of these sands are described. Niobium, yttrium and thorium are also present in significant concentrations. The results of prior mining practice, including concentration and separation of the heavy minerals are reviewed. Technical approaches to extraction of rare earths from Idaho black sand concentrates are discussed.

Jan 1, 1992

By Shengfan Zhou, XUEWEN WANG, Changjun Jiang, Mingyu Wang

In the process of extracting vanadium from stone coal by sulfuric acid leaching - P204 solvent extraction, Fe(III) can accumulate in the organic phase which reduces the extraction of vanadium. In order to eliminate the effects of the accumulation of iron, oxalic acid was used as the stripping agent to strip the Fe(III). The effects of oxalic acid concentration, phase ratio O/A, stripping time and shake velocity on the stripping of Fe(III) were studied. The results showed that the Fe(III) stripping rate can reach beyond 96% at the room temperature with 70g/L oxalic acid using an O/A of 2 at 160 rpm shake velocity for 20min. After 2-stage stripping, the concentration of Fe(III) in organic phase was 0.008g/L.

Jan 1, 2016

By Ray D. Peterson

The hydrothermal enrichment of chalcopyrite by CuSO, occurs in the absence of oxidizing or reducing reagants. Kinetics of the enrichment process were determined under autoclave conditions in the temperature range of 398°K (125°C) to 473°K (200°C). Covellite (CuS) formed first, followed by digenite (Cu,,,S), with rejection of iron to the solution. The kinetics have been explained by a model which includes diffusion during the first stage formation of covellite followed by surface reaction rate control when digenite be. The effects of particle size, temperature, pH, and cupric and ferrous ion concentrations on the leaching kinetics were examined. Additions of ferrous ion to solution markedly increased the rate of reaction.

Jan 1, 1994

By M. K. Alam

Chemical Vapor Deposition (CVD) processes are currently attracting special attention in materials processing. CVD processes are now used to produce special materials in the form of thin films, coatings, composites, and optical fibers. This process produces material of high purity, in complex shapes, and in a variety of microstructures. It is a capital intensive process, involving use of high cost raw materials. Modeling simulations have the potential of reducing the time for CVD . process design, and the need for experimentation. Modeling would, therefore, appear to be an attractive option for producing a product of acceptable quality. At Ohio University, progress has been made in modeling of CVD processes, specially in the areas of optical fiber preform fabrication, and fiber coating.

Jan 1, 1990

By M. J. Collins

Direct pressure leaching of zinc sulphide concentrates was started? commercially in October 1980. Continuing research and development studies at Sherritt and feasibility studies for a number of clients have defined various pressure leach configurations for integrattons with existing roast- 1 each operations and for grass roots plants. Existing and potential applications of zinc pressure leaching are discussed.

Jan 1, 1990

By Guanghui Li

Nickel pig iron (NPI), used as a substitute for electrolytic nickel, is able to reduce the production cost of stainless steel greatly. Aiming for preparing NPI from nickeliferous laterite ore, a pilot-plant scale test of coal-based rotary kiln direct reduction of laterite ore was performed and reported in this study. In this process, the ground laterite sample (18.85% TFe and 1.52% Ni) mixed with additives, pulverized coal and binder was briquetted into briquettes with the size of 40mm×40mm×31mm, laterite ore briquettes and reducing coal were charged into a rotary kiln with the diameter of 1.6 m and the length of 16 m, for a retention period of 6~7 hours, in which reduction section temperature was ranging from 950~1050 oC. The reduced briquettes were water quenched, ball mill ground and beneficated via low intensity magnetic separation. A magnetic concentrate, Ferronickel powder, with 86.9% TFe and 8.0% Ni was obtained, and the corresponding magnetic recovery of iron and nickel are 75% and 96.3%, respectively.

Jan 1, 2014

By Zhucheng Huang, Zhikai Liang, Lingyun Yi, Tao Jiang

"In this study, reduction of iron ore pellets was carried out at 800-950°C by simulating the atmosphere of typical coal gasification gas. The effects of temperature, gas composition and reduction degree on swelling were investigated respectively. Reduction degree was obtained according to the weight loss records. And volume changes of pellets during reduction were evaluated by infrared photography. Results showed that the pellet swelling increased with temperature and decreased slightly with hydrogen content in the reducing gas. The swelling peaked when reduction degree reached about 40% and then decreased to be stable finally. The microstructures of pellets during reduction were examined by reflected light microscope and relatively rational explanations were proposed for their swelling behaviors.PrefaceDirect reduction iron is an important and indispensable raw material for high-purified and high-quality steel in the electric furnace smelting. Gas-based shaft furnace direct reduction process has very strong competitative ability; however, this technique requires natural gas as reducing agent, so its development has been restricted by gas source and area. Compared with gas-based reduction method, coal based reduction method has the disadvantages of higher production cost and lower productivity. In China, coal resources are abundant and coal gasification technology is mature, and the development of coal gasification shaft furnace direct reduction process is promising. [1] The gasification methods of fixed bed method (Lurgi method), fluidized bed method (Undok method), airflow bed method (Texaco coal water slurry method and Shell dry powder coal method) have been put into use successfully. These syngas generated by different methods can meet the actual production requirement of shaft furnace. However, the compositions of the effective reduction gas in the syngas are quite different. The ratios of hydrogen and carbon monoxide (H2/CO) of Undok or Shell coal gas, Texaco coal gas and Lurgi coal gas are 0.4, 0.6~ 1.0 and 1.6~2.3, respectively. [2] In the coal gas direct reduction process, the swelling behavior of iron ore pellets is various due to the differences of the gas composition, reduction temperature and reduction degree, and it seriously affects the normal operation ofDRI production. [3-9] Therefore, the research on the swelling behavior and its mechanism of iron ore pellets in direct reduction were carried out in this paper."

Jan 1, 2013

By Dany Racine, Daniel Marceau, Denis Laroche, Dmitry Lukovnikov

Carbon base materials play a critical role in the performance of Hall-Héroult cell. The determination of their thermo-physical properties is of primary importance for modeling and designing complete cell systems. However, overcoming the associated experimental hurdles is complex and often underestimated. Of them are the Poisson’s ratio measurements and the continuous oxidation/burning of the materials at temperatures above 200°C. The novel procedure developed in this research is based on the Gleeble® 3800 system. Its vacuum chamber allows test with a chosen atmosphere at temperature of more than 1000°C. Young’s modulus, Poisson’s ratio and the coefficient of thermal expansion values can all be adequately measured using a single test. Cylindrical carbon samples (: 50mm, L: 100mm) were tested in the modified system at temperatures ranging from room to 950°C without any trace of oxidation. The resulting values were also in good agreement with literature data for a specific graphite material.

Jan 1, 2015