Search Documents

By Shengli Wu, Juan Zhu, Wei Huang, Xinliang Liu, Kaiping Du, Kaifa Zhang

Based on the furnace burden of high content of Al2O3, the process of softening and melting and the characteristic of primary slag were studied with the increase of MgO content in the sinter and adding some MgO into the pellet. The results showed that the content of MgO in the primary slag increased with the increase of MgO in the sinter and pellet. Meanwhile, the permeability of the furnace burden was improved because of low viscosity of high MgO primary slag. Compared with the increase of MgO content in the sinter, the increase of MgO content in the pellet can improved the softening and melting characteristic of the comprehensive furnace burden more effectively. More Mg-bearing pellet should be chosen in the comprehensive furnace burden for the purpose of improvement the fluidity of primary slag and the permeability of the furnace burden in the burden of high Al2O3 content.

Jan 1, 2015

By Fang-Qui Zu

Understanding the nature of liquid structures and properties remains an open problem for many fundamental and applied fields such as materials sciences and processing. And as well known, there is no other defined phase line above liquidus (TL ) in phase diagrams of ordinary binary systems. However, via different experimental resorts, our research results on over 30 metallic melts including alloys and elements show a novel physical image: temperature induced liquid-liquid structure transition (TI-LLST) can occur hundreds of degrees over TL. On the other hand, the solidification behaviors and structures out of the melts experienced TI-LLST are distinct from those out of the melts before TI-LLST. In this presentation, some characteristic aspects of the TI-LLST and the effects on solidification behaviors and structures are briefly summarized, and the pertinent rules and mechanism are also analyzed.

Jan 1, 2009

By M. D. Stephens

A new, one-step process for extracting titanium from titaniferrous materials has been demonstrated. In the process, depleted uranium tetrafluoride (DUF 4), a solid, is mixed with ilmenite (FeTi03) and heated to 900°C. Titanium is extracted in the vapor phase as titanium tetrafluoride (TiF4) and the DUF4 is converted to uranium-iron oxide. The process has been found to selectively fluorinate the titanium in ilmenite and is capable of producing high purity TiF 4 with very low iron content. TiF 4 can be collected by condensation or through reaction with a fluoride salt such as NH4F, KF, or NaF. The TiF4 produced from the process can be used to make titanium metal, titanium oxide, or fluorotitanate compounds. Since the fluorination process is highly selective for titanium, it avoids many of the separations and waste issues common to other titanium extraction processes.

Jan 1, 2001

By Dandan Jian, Christian Karcher

Information of liquid steel flow patterns inside the mold may be obtained from the velocity at the free surface (meniscus). This meniscus flow may be measured using the contactless electromagnetic technique termed Lorentz force velocimetry (LFV). It is based on the measurement of Lorentz forces acting on a magnet system when an electrically conducting metal melt interacts with the field lines stretched by the magnet system. Force sensor and the magnet system form a so-called Lorentz force flowmeter. In this paper we present a series of model experiments that demonstrate the feasibility of using two identical flowmeters that are arranged in a certain distance one behind the other. In this case, surface velocity may be determined by just cross-correlating the two force signals recorded by the two sensors. This technique is called time-of-flight LFV. A special prototype of a respective measuring device, called meniscus velocity sensor (MVS), has been developed to measure local free-surface velocity. In the present paper we describe experimental results of respective measurements in the model test stand LiMeSCo (liquid metal surface velocity correlation). To check the potential of the time-of-flight technique, in a first step we measure surface velocities during solid-body rotation of metallic substances. We observe that small modulations in the signals that are due to the natural unevenness of the solid body can be used to determine surface velocities. In a second step we apply the time-of-flight technique to liquid metal free-surface flow. Here we use the low-melting eutectic alloy GaInSn as a test melt. In this case we observe that the cross-correlations between the signals are much rarer and much weaker than in the solid-body experiments. We conclude that the presence of the localized magnetic fields, produced by the permanent magnets of the flowmeter, give rise to intense deformation of the free surface and the creation of surface waves. The field acts as a magnetic obstacle. We observe that the flow velocity is decreased right underneath the magnetic field and is accelerated in the side regions. This magnetic obstacle effect may restrict the determination of the local surface velocity in application.

Jan 1, 2012

By Dan Wang, Yuanbo Zhang, Guihong Han, Guanghui Li, Tao Jiang, Yanfang Huang

"Hematite concentrates are characterized by bad high-temperature reactivity and poor balling index, which restrict their large-scale application in the production of oxidized pellets. An organic additive, namely MHA, was authorized and used as binder recently in China. Compared with bentonite, the effects of MHA on compressive strength of hematite pellets at various firing conditions were investigated in this study. Experimental results showed the compressive strengths of preheated pellets with different binders were increased with increasing the preheating temperature and time. The compressive strength of preheated pellets with MHA binder was lower than that of pellets with bentonite, which can be ascribed to the high porosity of pellets with MHA binder. However, the compressive strength of roasted pellets with MHA binder was higher than that of pellets with bentonite. The compressive strength of finished pellets balled with MHA binder 1.0 wt% could meet the operation requirements of grate-kiln process.IntroductionHematite concentrates are characterized by bad high-temperature reactivity and poor balling index, which can lead to the appearance of those problems with increasing the energy consumption, shortening the useful life of equipment, and finally increasing the operation cost of oxidized pellets plants [1-2]. Some investigations have been conducted based on improving the pelletizing technique of hematite concentrates, such as pretreatment of raw materials [3-7], optimization of ore proportioning [8], addition of solid fuels [9-16], and so on. Employing high pressure grinding roller for the treatment of hematite concentrates revealed that the mechanical strength of wet green pellets could be improved. However, the mechanical strength of fired pellets was not improved obviously [7]. Huang, et al., pointed out that the preheating and roasting temperature may be decreased and the compressive strength of fired pellets could be increased by blending a certain proportion of magnetite concentrates with hematite [8]. Nevertheless, there are a variety of magnetite ores different in physical and chemical properties in China, resulting in the instability operation [17]."

Jan 1, 2012

By William Gregg

Recent environmental and workplace safety legislation has Imposed more stringent limits on the amount and type of particulate emitted Into the air. In the past, the mass of particles contained In a volume of air was the governing criteria. Now the size and precise chemical nature of the particulate must be known and controlled In addition to it's ?mass. Processors of metallic materials have to implement stricter control practices and more efficient control equipment to meet the new regulations. Pulse-Jet dust collector systems are being used to control particulate emissions from various process gas streams. Pulse-jets :are also being used for maintaining a healthy environment In the workplace. this paper will discuss the impact of these regulations, the control techniques used to comply with such regulations, and the equipment needed for compliance.

Jan 1, 1992

By S. R. Reddy, R. G. Reddy

"The Margules equation is used for interpreting excess Gibbs energy of several ternary systems. In the present study activity coefficient of a dilute solute, 2, in a binary solvent 1-3 was derived. The derived expression is used to interpret logarithmic activity coefficient of oxygen and sulfur in several metallic systems. Self interaction parameter of the solute is derived from the partial function of solute using constant compositional path. An expression for logarithmic activity coefficient and self - interaction parameter of solute is also derived using Maclaurin infinite series. The derived equation is based on Maclaurin infinite series used successfully to deduce thermodynamics of self interaction of oxygen as a interstitial atom in two metallic systems. The predicted thermodynamic parameters values using Maclaurin infinite series and Margules equations, are in excellent agreement with the experimental data and also our predictions are far more accurate than the predictions made by other models.1 IntroductionIn most of the pyrometallurgical high temperatures processes, interactions of solutes such as oxygen, nitrogen and sulfur, with the solvent atoms are most important during refining processes. There are numerous theories are developed [1-25] to interpret the thermodynamics of solutes in multicomponent alloy systems. Which are mainly developed using statistical or Quasichemical equations.Wagner [4] developed one energy parameter ideal solvent model based on activity coefficient of solutes compositional dependency. He used one energy interaction term which is not able to account for interaction energy parameters for the same solute concentration at different solvent compositions and also it is ineffective model to predict for strong interacting systems."

Jan 1, 1996

By S. Seetharaman, Du Siehen

"In the processing of molten metals, it is extremely important to monitor continuously the concentration levels of various minor elements. In the production of common metals like copper, iron and aluminium electrochemical sensors involving solid as well as liquid electrolytes are being increasingly used to measure the concentrations of minor elements. The present paper deals with the electrochemical principles underlying these measurements and the possible errors involved. One of the major difficulties in the case of the solid electrolytes is to correct for the consequences of the electronic contribution to the conduction of the electrolyte.The application of the electrochemical sensors for molten metals processing involves designing of these probes to withstand the industrial operating conditions. In this respect, significant achievements have been made with respect to the design of oxygen probes for liquid metals in general and liquid copper in particular. Some of the salient design features are discussed in the paper. The application of auxiliary electrodes for impurities in molten metals like phosphorus in copper and silicon in iron are taken up. The development of oxygen sensors for slags is given special attention. Recent developments in the field of sensor technology, as applied to metals processing are highlighted.1. IntroductionThe rapid technological advancement today require precise control of the process parameters and the impurity levels. Most of the molten metals processing in industrialized countries are often steered by suitable computer models, either phenomenological or simulations based on theoretical principles. These models often require that the process parameters are continuously monitored so that the progress is followed and modified suitably as and when required. It is common practice to measure temperatures by incorporating temperature sensors at the various strategic points of the reactor. In the case of monitoring the composition changes in the various phases, the method of sampling followed by routine chemical analysis involves a time lag as well as uncertainties in sampling and analysis. In this respect, electrochemical sensors have the advantage of generating accurate data when properly applied and increasing attention is being paid in the development of electrochemical sensors for various common species in molten metals processing. In the present paper, the developments in this area over the years are outlined and typical process applications are discussed. A greater emphasis will be laid on sensors based on oxygen conducting electrolytes and their application to the production of common metals like iron and copper."

Jan 1, 1996

By Xiang Zhu

Xidagou is the largest waste water discharge channel of the Anshan Iron and Steel Complex (AISC) with average flow rate of 8000 cubic meters per hour, which is about 75% of the total effluent of the AISC. The waste water from Xidagou seriously polluted the Taizi River Basin. In order to meet the Chinese Class V Standard for Surface Water Discharge and the Standard for Recycled Industrial Water Reuse, with the aid of the World Bank, the AISC began the treatability studies in 1991. Based on the bench-scale test, the AISC carried out pilot-scale treatability studies on three different treatment processes and five different chemical coagulants for more than half a year in 1992. The study results show that the processes of primary sedimentation- chemical mixing and flocculation-secondary sedimentation-filtration can meet the requirement and that PFS and PAM are effective and economic chemical coagulants.

Jan 1, 1994

By J. H. Meza V

La Caridad operated at only 65% of design capacity during the first five years of operation. After the first major shutdown and repairs to the furnace in mid- 1992, the smelter quickly reached 95% of design capacity. Converter operation is now more efficient; blowing times have decreased from about 1.7 to 1.2 min/ton of matte. Anode copper production is now 15000 tons/month. The increased efficiency provided by better coordination and scheduling ensures La Caridad's ability to operate at present and expanded production capacity while simultaneously meeting environmental control standards.

Jan 1, 1993

By Ivan Imris

The common problem of new and conventional technology of copper production is the copper losses in the slags, which may be divided into mechanical and physico-chemical losses. In the first group can be included particles of mechanically entrained or floated unsedimented matte particles which coexist with slag. On the other hand, the physico-chemical losses are caused by solubility of copper in the slag in the form of sulphide and oxide. The copper losses in the slags from different processes has been predicted by calculation from thermodynamic data and compared with those determined by microscopic examination and quantitative electron microprobe analysis. Depending on the forms of copper losses in the slag the reduction of copper losses in the slag or the slag cleaning process could be suggested.

Jan 1, 2003

By H. Y. Sohn, S. PalDey

"A new chemical synthesis process for the preparation of intermetallic compounds has been developed. It involves the vapor-phase reduction of mixtures of constituent metal chlorides by magnesium vapor to produce intermetallic compounds in the form of fine powder. The advantages of the process include (a) the use of inexpensive raw materials, (b) low reaction temperatures, and (c) products in the form of fine particles. Titanium and nickel aluminides were prepared by this method. The effect of AlCl/TiCl3 partial pressure ratio on the formation of different titanium aluminides was studied. A two-phase mixture containing 80 mol % of TiAl and 20 mol % of TiA13 formed at an AlC13/TiC13 ratio of 10. The amount of TiA13 was maximized to 72 mol% at an AlC13/TiC13 ratio of 16. The maximum conversion of the limiting chloride TiCl3 was 94 % . In the case of nickel aluminides, NiAI, NiAl3, and Ni2Al3 were formed by reducing mixtures of NiC12 and A1Cl3 vapors. The effect of the partial pressure ratios AlCl3/NiC12 and Mg/NiC12 on the formation of nickel aluminides was studied. The maximum content of NiAl obtained was 98 mol % . At the AlC13/NiC12 ratio of 19, a two-phase mixture of 17 mol% of NiAl and 83 mol% of NiA13 was produced. The product particles were very fine in the size range of 0.05 to 0.2 µm.A. IntroductionIntermetallic compounds are attracting much attention [1]. Titanium and nickel aluminides have attracted a great deal of attention from the aerospace as well as automobile industries because of their potential for high-temperature application (e.g., low density, good oxidation resistance, and high-temperature strength retention [2, 3]). Gamma TiAl and two-phase (TiAl and Ti3Al) alloys [4] are used for gas turbine engine rotational components as well as automobile exhaust valves. TiAl3 is one of the most extensively investigated aluminum-rich intermetallics. Nickel aluminides are attractive because of their low densities, relatively high melting point and good high-temperature strength properties. For example, Ni3Al shows increasing rather than decreasing yield strength with increasing temperature [5]."

Jan 1, 1998

By S-L. Jämsä-Jounela

Fault diagnosis systems have attracted growing interest in a number of engineering fields. The number of applications has increased and successful results have been widely reported. The fault diagnosis system presented in this paper is integrated, and it monitors the states of the process and performs fault detection and diagnosis on the process equipment. The monitoring of process states is carried out by means of Kohonen Self-Organising Maps that is a powerful tool in visualisation and analysis of high dimensional data in engineering applications. This paper presents the results of SOM analysis carried out on the Outokumpu flash smelting process. The subsystems analyzed in more detail are the condition of the concentrate burner, the condition of the gas line on the basis of the pressure distribution in the process and the cooling water circulation of the waste heat boiler, and the condition of the furnace and furnace equipment on the basis of the temperature distribution in the furnace and gas line. Keywords: Fault diagnosis, Process monitoring, Kohonen Self-Organising Maps, flash smelting

Jan 1, 2001

By Stanko Nikolic

One of the keys to success in process development is incremental scale-up, allowing for potential problems to be identified and rectified. The ISASMELT™top submerged lance (TSL) process was developed to maturity using this method by Mount Isa Mines, now owned by Glencore. Commercialization only occurred once the process had been proven on each scale and as a result the ISASMELT™ technology now operates successfully around the world. An important parameter in the evolution of the technology has been the furnace campaign life. The initial commercial scale furnaces had minimal water-cooling. Although this led to shorter campaign lives, an extended development program resulted in the achievement of four-year campaign lives, without any water cooling. In tandem to the refractory designs Glencore Technology, supplier of the TSL technology, has progressed cooled copper lining designs for application to both the ISASMELT™ and ISACONVERT™ furnaces allowing for ultimate flexibility in the lining choice. This allows each ISASMELT™ operating site to minimize their overall life-cycle costs by balancing their campaign life with lining costs, energy inputs, and other shutdown requirements.

By Edgar E. Vidal

The deposition of ceramic materials onto substrates is of special interest in the development of surface related technologies. Research interest has been placed on using thermal plasma as the deposition method, specifically inductively coupled plasmas. Many different modifications to the same basic principle of deposition have been performed through out the materials research community. Such a technique may have many advantages over more conventional techniques, such as high deposition rates, high surface area coverage, clean energy source, no contamination from electrodes and operation near atmospheric pressures. Materials deposited vary from simple oxide systems like TiO2 to more complex structures like ternary oxides and nitrides. This paper reviews recent developments relative to the inductively coupled plasma deposition of thin films.

Jan 1, 2003

By Musa Karakus

The sedimentary iron ores of Alsace-Lorraine, France have very high phosphorous contents that average 0.7% and are as much as 2.19% P. Ores from the Tucquegnieux and Joeuf mines have been studied by cathodoluminescence microscopy, X-ray diffraction, scanning electron microscopy, and electron microprobe analysis in order to fully characterize the mineralogy, size, shape, and distribution of the deleterious phosphate grains. The phosphorous occurs as collophane, a carbonate fluorapatite, in ten morphological forms, most abundantly as microcoprolites, but also as intraclasts, concentric layers, and cortices in ooids, phosphate replaced ooids and bioclasts, phosphatiC shells, fossil infillings and internal molds, fish teeth, phosphatiC laminae, and cements between the goethite ooids. About 95% of the phosphate grains are sufficiently large that relatively fine grinding fol'lowed by reverse flotation would be expected to be effective in significantly diminishing the phosphorous content of the concentrates.

Jan 1, 1989

By R. M. Taylor

Lime addition to acid mine drainage (AMD) leads to precipitation, predominantly of metal hydroxides and calcium sulfate, and is the benchmark for remediation by precipitation. Geo2 Limited of Melbourne, Australia has developed and patented a novel alternative precipitation scheme based on the formation of mixed valency, M(I1)-M(III), hydroxide sulfate salts. When the composition of AMD is appropriate, the Green Precipitate Process provides a useful and more effective alternative to conventional liming. The characteristics and utility of the Green Precipitate Process are described in terms of the underlying chemistry, and a case study where the Green Precipitate process outperforms conventional liming. A mobile pilot pipe reactor rig which was built by Geo2 to demonstrate the process, and used successfully in both Australia and the United States, is described.

Jan 1, 1998

By Mohamed Y. Bakr, Aly M. Abdel-Rehim

The present work is related with mechanical activation of processing of Egyptian wolframite by simultaneous ball-milling and pressure alkaline leaching, to improve the recovery of tungsten from wolframite. The results show a total recovery of tungsten from wolframite (97.8- 98.7%) by simultaneous ball–milling and alkaline leaching at temperature 175-200oC. It is concluded that processing of wolframite by simultaneous ball- milling and leaching is mechanically activated and accelerated as a result of the grinding action of steel balls that caused the immediate rupture by continuous removing the product layer of the reaction ( sodium tungstate and iron and manganese hydroxides ) from reacting particle surfaces. This leads to the exposing of fresh and activated wolframite particle surfaces to alkaline leach solution and consequently the acceleration of the reaction of wolframite leaching .The results of the kinetic study 0f alkaline processing of wolframite and its mechanical activation show that the system is under kinetic control.

Jan 1, 2015

By Fei Ruan, Chang Jie, Jieyu Zhang, Jifang Xu, Kuochih Chou

"Viscosity is an important physical parameter of slag in metallurgical processes. Most studies of aluminosilicate and aluminate systems assume that aluminum occurs in tetrahedral coordination. In this case, the O/Al value was utilized to describe the slag structure in terms of the network character of aluminosilicate and aluminate systems. Composition and viscosity data from the literature and the trends were analyzed according to the O/Al value and temperature. It is shown that the O/Al value explains the trends in more than ten systems, containing more than 200 data points. In aluminosilicate system, the trend that viscosity value changed with the O/Al value which implies that alumina works as network modifier such as basic oxides or works as network former. In aluminate system, irrespective of the system and temperature, viscosity decreased steadily when O/Al value increased.IntroductionMetallurgical slags, which are made of oxides and many also contain fluorides, play an important role in metallurgical processes such as iron making, steel making and secondary refining processes. Aluminosilicate slags are applied in a wide range in metallurgical processes. A polymerizing effect of the addition of aluminum and an association of aluminum with low-field strength cations is further supported by the physical variations in aluminosilicate and aluminate systems. The behavior of alumina in silicate melts has been studied by various authors [1-6]. It is generally accepted that Al2O3 is amphoteric [7] because Al3+ ions can behave in profoundly different ways in a silicate melt. When added to a pure silica melt, Al2O3 acted as a network modifier, breaking the bridging oxygen of the pure silica network, thereby decreasing the viscosity in a similar manner to other network modifiers, such as CaO, MgO etc. to form [1/2Ca (AlO4)]4- complexes. However, when added with alkali or alkali-earth metal oxides, some of the Al3+ ions assumed tetrahedral coordination and replaced Si in the liquid network, the missing charge was compensated by Me+ or Me2+ ions. Therefore Al2O3 acted as network former [8, 9]."

Jan 1, 2011

By S. Seetharaman

In the processing of molten metals, it is extremely important to monitor continuously the concentration levels of various minor elements, In the production of common metals like copper, iron and aluminium electrochemical sensors involving solid, as well as liquid electrolytes are being increasingly used to measure the concentrations of minor elements The present paper deals with the electrochemical principles underlying these measurements and the possible errors involved. One of the major difficulties in the case of the solid electrolytes is to correct for the consequences oldie electronic contribution to the conduction of the electrolyte. The application of the electrochemical sensors for molten metals processing involves designing of these probes to withstand the industrial operating conditions. In this respect, significant achievements have been made with respect to the design of oxygen probes for liquid metals in general and liquid copper in particular. Some of the salient design features are discussed in the paper, The application of auxiliary electrodes for impurities in molten metals like phosphorus in copper and silicon in iron are taken up. The development of oxygen sensors for slags is given special attention. Recent developments' in the field of sensor technology, as applied to metals processing are highlighted.

Jan 1, 1996