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By George Kazonich

The high costs and environmental problems associated with making iron and steel in the United States is driving the development of new technologies to replace the blast furnace. A prototype reactor incorporating rocket technology was designed and built. This rapid rate reactor was operated successfully and consistently made iron metal. Minus 325-mesh magnetite particles could be reduced to iron metal in less than 50 ms in a high temperature flow through reactor. Iron product was recovered inside the reactor and in a downstream cyclonic separator. The results of typical operation and how parametric changes affected the reduction of iron ore concentrates are discussed.

Jan 1, 1993

By Hector Henao

To provide thermodynamic data for converting the nickel matte to liquid nickel, an experimental study was conducted in the phase equilibrium between the Ni-S alloy and the CaO-Ah03 based slag melted in a MgO crucible at 1873 K under controlled Pso2 of 10.1 kPa and pO;, in a range between 2.5x,IO,2 and 10.1 Pa by using CO-C02-S0Z gas mixtures. The content of nickel in the slag at POz of 10.1 Pa, above which solid NiO is expected to precipitate in the equilibrium state, was found to be 4.1 mass% and the contents of sulfur and oxygen in the nickel melt were 0.4 and 0.2 mass%, respectively. It was clarified that increase in the temperature reduces the solubility of nickel in the slag and the contents of sulfur and oxygen in the alloy. The distribution of minor elements such as gold, silver, copper, cobalt, iron, arsenic and antimony between the Ni-S alloy and the CaO-AI20) based slag was also studied. The distribution ratios of iron and cobalt, defined by (%X in slag)/[%X in alloy] where X is the minor element, are larger values than that of nickel, while those of copper, silver and antimony are similar to that of nickel. The distribution ratios of arsenic and gold are lower than that of nickel in the higher range of oxygen partial' pressure.

Jan 1, 2003

By Tian Sugui

By means of the long-term aging treated, creep properties measuring and microstructure observation, an investigation has been made into the microstructure and creep behavior of the casting and rolling GH4169 superalloy after long-term aged. Results show that, after the casting and rolling GH4169 superalloy treated by long-term aged, significant amount of " phase are dispersedly precipitated within the grains of the alloy, and some of the NbC, Cr7C3 carbide are distributed along the grain boundaries. In the range of the applied stresses and temperatures, the creep activation energies and stress exponents of LTA GH4169 alloy during steady state creep are calculated to be Q=541.1kJ/mol and n=16.2, respectively. During creep, the deformation mechanism of LTA GH4169 is thought to be the twinning and dislocation slipping within the twinning regions, and the damaging mode of the alloy is the intergranular fracture, and the non-smooth crystal surface is displayed in the fracture regions of the alloy. Thereinto, the carbides film formed along the grain boundaies has a few effect on the strength between the boundaries, which is a main reason of resulting in the alloy possessing a longer creep lifetimes.

Jan 1, 2009

By Giuseppe Bonifazi

Minerographic and petrochemical research was carried out on crude ore samples from the complex polymetallic Zn-Cu-Pb sulfide ores of , Sotiel in Huelva province west of Seville, Spain. A computerized image analysis system was used to define the structural and textural characteristics of the ore to obtain information on the degree of liberation of the different minerals (i.e. pyrite, sphalerite, galena, chalcopyrite). Techniques of digital multispectral image processing of reflected light microscopy images were used. Particular structures were identified by means of mineral associations and numerically quantified to obtain useful information for designing beneficiation processes.

Jan 1, 1991

By R. Burkhard

Recovery of metals from complex mixed wastes is a challenging task of modem material and waste management strategies. Thermal methods are an important tool in this respect. Plasma turned out to be particularly useful for treatment of complex or toxic wastes and residuals. In order to study plasma processes at reasonable costs, a pilot plasma plant has been used and wastes like ~pent Raney-Nickel catalysts, copper and ah.:lminum drosses, and. other metal containing wastes were investigated. The paper summarizes the most significant findings

Jan 1, 1995

By I. S. Blair

The introduction of the 36 MVA smelting furnace at Mufulira, and the experience gained during the first five years of operation have been described previously (6). Based on this experience the furnace was rebuilt in 1977., Details of the modifications made during this rebuild are described. Subsequent to the rebuild, refractory failures, particularly in the electrode ring bricks of the sprung arch roof, continued to cause concern, and repair and improved roof control methods are described. Electrode breakages continued, but developments in casing design and electrode preparation have resulted in significant improvements. Modifications in the electric furnace gas handling system are outlined, together with details of further changes to be implemented in the near future. The systems developed for metallurgical control of the furnace and the thermo-dynamics of the process are discussed. The electric furnace at Mufulira is now operating at above design production levels, and has decisively justified the choice of this technology in situations with inexpensive electric power. The potential for further increases in production capacity from the Mufulira unit, and improvements in design for new units are discussed.

Jan 1, 1983

By Jianguo Yin, Wenqiang Yang, Xiaoli Yuan, Juan An, Wentang Xia

Low grade iron ore with phosphorus (LGIOWP), a raw and wasted industrial solid material was used as an adsorbent to remove Pb(II) from wastewater. The effects of initial pH value, adsorptive time, initial Pb(II) concentration, adsorptive temperature and LGIOWP dosage on the Pb(II) removal efficiency were studied. The results show that the Pb(II) removal efficiencies exceed 99.4% and Pb(II) concentrations are less than 0.30 mg/L under the conditions of pH value 7.0, adsorptive temperature 50 oC, adsorptive time 30 min, initial Pb(II) concentration 100 mg/L, particle size <0.25 mm, adsorbent dosage 5 g/L and stirring speed 260 r/min. After Pb(II) removal reaction, the Pb(II) concentrations of wastewater completely accord with the requirement of national discharge standards of pollutants from lead and zinc industries (GB 25466-2010) (TPb= 0.5 mg/L) in China. Therefore, it can be concluded that LGIOWP is a new low-cost adsorbent which is suitable for the adsorption of Pb(II) from wastewater.

Jan 1, 2015

By James B. Pfeiffer

TETRA Technologies, Inc., has applied its HDS? metals precipitation system to control a mine drainage problem. The effluent from the mine contains primarily zinc, manganese and iron, plus varying small amounts of cadmium, copper and lead. The flow from the mine averages 350 gpm, and varies considerably depending on season and weather conditions. The plant was designed to treat 1000 gpm of the water and generate a dense sludge suitable for recycling. The HDS? system contains a number of reactors, followed by post filtration and meets stringent metals discharge criteria as specified by New Source Performance Standards.

Jan 1, 1994

By H. M. . van der Donk

In this work an overview is given about the techniques available for the removal of metallic impurities from molten aluminium. The overview is focused on the removal of iron. Also, some experimental results are given about the creation of iron-rich intermetallic compounds in an aluminium system, which are subsequently removed by gravity segregation and filtration techniques. This work is part of an ongoing research project of three major European aluminium companies who are co-operating on the subject of recycling of aluminium packaging materials recovered from household waste by means of Eddy-Current techniques. Using this technique the pick-up of some contaminating metals, particularly iron, is almost unavoidable.

Jan 1, 1995

By Norihiro Murayama

Syntheses of zeolitic materials were carried out from coal fly ash by alkali hydrothermal treatment as part of the reuse and recycle technologies of coal ash, For the obtained zeolites, the cation exchange capacity and acid resistance, which are very important in the practical use of cation exchanger in aqueous solution, are investigated during this stufY, The cation exchange amounts of the NaP, CaP and K-CHA zeolites are measured for various cations such as K+, Na +, NH4+ Ca2+, Mg2+, Pb2+, Cd2+ and so on. The change in crystallization degree are researched as a function of pH. The simultaneous removal ability of NH4+ and PO43- in solution is examined for an example of the water purification with CaP zeolite. From these results, the characteristic and its mechanism of cation exchange are clarified for the various zeolitic materials obtained from coal fly ash.

Jan 1, 2003

By M. C. Furerstenau

Adsorption behavior of various surfactants on sulfide minerals is very much affected by the nature of the surface of the mineral. Since sulfides are naturally meta-stable, oxidation occurs when they are exposed to air, especially in aqueous environments. As a result. oxygen assumes a major role in sulfide flotation. Mechanisms of adsorption of various thiol collectors on sulfide minerals have been reviewed. The electrochemical behavior of various sulfide minerals has also been reviewed. Flotation behavior of galena, chalcocite, sphalerite, pyrite, chalcopyrite and pentlandite has been presented together with the. flotation of copper sulfide- nickel sulfide ore.

Jan 1, 1993

By Vitalij K. Pecharsky

Recent interest in complex aluminohydrides as potential near ambient, ultra-high capacity, solid-state sources of hydrogen (e.g., for fuel cells) calls for an improved understanding of the processes occumng in these hydrogen-containing materials during both the release and the uptake of hydrogen. Lithium aluminohydride (LiAlH4) rapidly releases 5.2 wt. % of hydrogen (i.e., nearly four times more than LaNis-based alloys) during mechanochemical processing at ambient conditions in the presence of transition metal catalysts. Using a variety of solid-state characterization techniques, the mechanochemical transformations in a series of LiAlH4 - metal catalyst systems have been examined and preliminary insights on the mechanism have been obtained. Surprisingly, the well-known hydrogenating-dehydrogenating catalysts, such as Ni and Pt, are practically inactive in the mechanochemical dehydrogenation of LiAlH4.

Jan 1, 2002

By Magnus Ek

After the installation of three new converters as part of the recent expansion of the Rönnskär smelter completed in 2000 work continues to further improve the converter operation. The converter upgrade led to an increase in blister copper taps from 150 tons per batch to more than 300 tons. The total cathode copper production increased from 130,000 tons in 1999 to 230,000 tons in 2001, the first year in full production. In recent years focus has been to improve operating practise, maximize the blowing time, extend the converter campaigns hence to reduce the specific brick consumption and improve the converter slag composition.

Jan 1, 2005

By A. Mukhopadhyay

Gas stirring, simultaneous arcing, chemical additions are some basic steps in the secondary steel making. From tap to team however, there are enough uncertainties and several in-situ decision making required to match the fmal composition and temperature in the given amount of processing time. Currently available control algorithms rely on overall material and heat balance coupled with a self-learning regression based tuning of model constants. In this paper we demonstrate the capabilities of Computational Fluid Dynamics (CFD) in modeling and analyzing the thermo-chemical aspects of secondary Steelmaking. These models take advantage of scientific and engineering advances in computational tools and provide almost real time speed of analysis. This can be a very effective tool for operator training, process debugging and improvement as well as new innovations. Keywords: Argon purging, Secondary steelmaking, Arcing, Ladle Furnace, Process Control.

Jan 1, 2003

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 A. A. Bustos

A model was developed to simulate the blow-by-blow operation of the converting process. From the weights, compositions and temperatures of all converter feeds the model calculates the composition and tonnage of both converter matte and slag as well as bath temperature at the end of each blow. The development of the model and its application to the converter aisle operation are described. There is good agreement between model predictions and observed results. At the present time the model is being used to investigate different converting schemes and their effect on pay metal recoveries, slag chemistry and temperature of the bath. Future work involves the use of the simulation model as a process control tool for the converting operation.

Jan 1, 1988

By K. Yamada, T. Takaoka, A. Ozeki, M. Yamaga, Y. Kawai, S. Nishioka, Y. Kikuchi

"Recently, smelting reduction of chromium ore in BOF has been actively investigated as a key unit process for an innovative future stainless steelmaking. The prominent feature of this new process route is energy and process saving, and production cost saving. The development is already in the midst of application to the commercial production, however there still remain the following key technologies to be established for the full use of the process. One is a speed up of the reduction of chromium ore to match with sequential continuous casting, and the other is efficient combustion of carbonaceous materials in BOF to reduce their consumption, and hence to assure the steel quality. High degree of post combustion technology and new charging technology, i.e., ore-coal-flux-oxygen mixed injection, could be effective for those two subjects. In 2000 or beyond, the new process would have become quite popular owing to the establishment of those key technologies.Introduction Since stainless steel was invented, its production has continued to expand because of its attractive combinations of functions of excellent corrosion resistance, good formability, a pleasing appearance, and a wide range of strength levels. New types of stainless steels as well as new applications are continually being developed.Compared to the production of ordinary steels (1), stainless steel production (2,3) shows steady growth worldwide, while the former production remains on the same level, as Figure 1 shows. It can be estimated that future production would show further growth since materials consumer demands are more fashionable, or more functional, which could be satisfied by stainless steels.Thus market needs would be met, if it could be produced with reasonable production cost. The emergence of an innovative production technology is then potentially requested as VOD and AOD processes have emerged, which has saved substantial production cost. This paper describes a possibility of a future stainless steelmaking process, which uses the in-bath smelting reduction of chromium ore in BOF, and which would save production as well as energy cost."

Jan 1, 1988

By Autumn Fjeld

The filling and solidification of an industrial scale composite casting has been simulated to investigate the re-melting of the outer shell material during casting. Production of a composite requires a two-step casting process which includes centrifugal casting of a hard outer shell material and subsequent conventional ingot casting of a tough core material into the shell-mold assembly. During casting of the core, a thin layer of the shell material re-melts and mixes with the core material producing a bonding layer of intermediate composition. The present numerical model employs the volume of fluid method and an enthalpy-porosity technique to couple the filling of the core material and re-melting of the shell material. The interface between the two materials is tracked and can be used as a guide to examine the extent of melting and, to some degree, mixing of the two fluids and species diffusion.

Jan 1, 2008

By Qinmeng Wang

The oxygen bottom blown copper smelting process is a new technology which has been widely applied to the copper production in China. In this work, a computational thermodynamics model for this technology has been established, based on smelting mechanism and theory of Gibbs free energy minimization. The calculated results from the model agree well with the actual industrial data, indicating that the model can be used for the predictions under different operating conditions. The tendencies of the key parameters (such as Cu losses and Fe3O4 content in slag) and the distribution ratios of the minor elements (such as Pb, Zn, As, Sb and Bi) can be predicted by adjusting the oxygen/ore ratio charged into the bottom blown copper smelting furnace. The model can be used to monitor and optimize the industrial operations of the oxygen bottom blown copper smelting process.

By Zhijing Zhang, Ramana G. Reddy

"The viscosity of molten oxides is one of the important physical properties since viscosity has a decisive influence on fluid flow. The knowledge of the viscosity of molten oxides is essential for modeling and controlling of metallurgical process. In the present study, viscosities of high basic Na2O-B2O3 and Na2O-SiO2 binary melts and viscosities of Na2O-SiO2-B2O3 ternary melts were measured as a function of temperature and composition. Experiments were carried out using rotary viscometer and graphite components. Our experimental results were compared with those in literature. Based on the current experimental data, the previously developed viscosity model was modified. The characteristic features of viscosities of these melts have been discussed. The predicted viscosity results are in excellent agreement with the present experimental data in the temperature range with molten state samples. IntroductionThe viscosity of molten oxides is one of the important physical properties since this property has a decisive influence on fluid flow, and is one of key factors to be taken into consideration in process modeling. The manufacturing operations require the viscosity of molten oxides to be within certain ranges. Although, some viscosity measurements on borosilicate systems have been carried out [1-4], the viscosity data in literature are available only for a few temperatures and cover small composition ranges. The agreement between the results of these works is not satisfactory [I-4]. Even the viscosities of binary systems Na2O-B2O 3 and Na2O-SiO2 generally are well studied, the available viscosity data in literature are only found in the composition range of O to 0.333 mole fraction ofNa2O. The aim of the present study is to provide a base with accurate experimental data for reliable model extrapolation."

Jan 1, 1999