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By Cheng Pan, Xuewei Lv, Guibao Qiu, Chenguang Bai, Meilong Hu

"Physic-chemical properties of slag at high temperature play an important role in the pyrometallurgical process of production of ferronickel alloy. It determines the operation efficiency, metal recovery ratio, energy consumption and the distribution of elements like S and P between the slag and metals. In the present work, the effect of MgO content in the slag on melting features and viscosity of the slag was investigated. The MgO content in the SiO2-CaO-MgO-Al2O3 -FeO in the quinary slag system varied from 14.5% to 22.5%. The results shown that all slag samples begin to softening at the same temperature, the softening temperature, melting temperature, flowing temperature decrease with the increase of MgO content when the MgO content is in range of 14.5 and 20.5 pct mass, and when MgO content up to 22.5 percent, the temperatures increase sharply. Besides the inflection point temperature of viscosity-temperature curve increase with the increase of MgO when the MgO content is in range 16 and 22.5 pct mass.IntroductionNickel is very important to modern society, without it, we would not be able to share many things in our daily life, such as airplanes, computers and many stainless steel appliances in our homes and workplaces1.. It is the essential element of the stainless steel making, and about 65% of the nickel consumed in the world is used to make stainless steel2., so with the increase of stainless steel, the nickel production and demand has continued to increase3.Nickel is produced from two distinct ore types: nickel sulfide deposits and oxide nickel laterite deposits. The great majority of world’s known nickel resources are contained in laterite deposits3.. The laterite ores are normal classified into two groups: the high-iron laterite ore and high-magnesia laterite ore1. Typical composition of high-magnesia laterite ore is in the range 1-3%, and these ores are suitable for pyrometallurgical process to produce ferronickel4."

Jan 1, 2012

By Tadashi Aiura, Yasuhiro Miura

"A small amount(0.2mass%) of Scandium(Sc) was added to the 7.NOl and 5083 Al alloys as a refiner and stabilizer of microstructure, and the resulting microstructures were discussed in comparison with the effects of the conventional additives. The followings are summarized: 1) in the as-solidified structure, a ·decreased tendency of constitutional supercooling and increased solubility of Mg were recognized for the Sc-added 5083 alloy. Sc is a -better microstructure refiner for the 7N01 alloy than Zr, in a sense that it does not suppress the favorable effect of· coexisting Ti. 2) Sc effectively suppresses recrystallization both in the 5083 and 7N01 alloys. 3) The rod like primary Al3Sc crystals formed during solidification, as well as the fine dispersion of Al3Sc precipitates formed by subsequent heat treatment, can act as a strong recrystallization suppresser. IntroductionThe 7N01 and 5083 alloys are the most popular industrial Al alloys and they are widely' used for various structures because of their superior properties. Fine macro and micro structures of the materials are required for obtaining acceptable sec resistance,consistent appearance of anodized surface and good weldability, as well as good mechanical properties. In order to produce fine grain structures, transition metals, such as Cr, Zr, and Mn, have been conventionally added.It has been reported that Sc is an efficient refiner [l, 2] and can be an alternative for the conventional and also suppresses recrystallization in Al alloys [3,4]. Scandium is the lightest transition element and forms an equilibrium intermetallic phase. The equilibrium phase, Ll2-Al3Sc, is coherent with the matrix, and of _spherical shape. A fine dispersion of the spherical precipitates is obtained by quenching and aging after solutionizing annealing. The authors have already reported a part of the experimental results on the effect of Sc on the as homogenized microstructure of the 5083 alloy [5]. In the present study, the effects of Sc on the macro and micro structures of the industrial high strength Al alloys(7N01 and 5083) for extrusion are investigated, and the superior role of Sc as a grain refiner is shown"

Jan 1, 2000

By Axel Hoppe

Although Tantalum is not usually regarded as a precious metal, its pricing structure is very similar to that of Silver. Different from precious metals, Tantalum has only industrial applications and its use is about 1000 metric tons per year. The intrinsic value of Tantalum already in .the past was a driving force for its recycling. Based on these facts the Tantalum industry world-wide is approaching the closed-loop concept of its recycling. A detailed material flow of Tantalum processing as well as recovery of residues and used products will be discussed.

Jan 1, 1995

By Tiejun Chun, Jian Pan, Deqing Zhu, Zhiyong Ruan

"In this paper, the desulfuration of pyrite cinder pellets was carried out. Phase analysis shows that most sulfur of pyrite cinder exists in the form of elementary sulfur. Most sulfur was removed in preheating stage. 81.25% sulfur was removed and the average SO2 concentration of exhaust gas was 1365ppm when the pellets were preheated at 950oC for 9 min. The final product, assaying 62.42wt%Fe and 0.02wt%S content at 96.88% desulfuration was achieved under the conditions of preheating at 950? for 9 min and roasting at 1200? for 15 min, which can be used as the burden for blast furnace.IntroductionPyrite cinder, as a subsidiary product of sulfuric acid production by roasting of pyrite ores, was solid waste in sulfuric acid enterprises. According to the statistics, the annual production of pyrite cinder is about 15 million tons in China. Besides, there is lots of pyrite cinder deposited for many years [1-3]. The pyrite cinder consumed in the cement and other industries as auxiliary additives only accounts for less 30% of its total discharge and the left is stored in waste pond, occupying much land and polluting environment in China [4-5]. Moreover, pyrite cinder contains iron between 30-63% which can be utilized as a cheap raw material for ironmaking by sintering or pelletizing processes, which can not only prevent pollution but also provide cheap raw materials for ironmaking [6-7]. However, compared to traditional iron ore concentrate, pyrite cinder possesses higher sulfur content."

Jan 1, 2012

By Fangqing Yin, Qingyu Deng, Zhengfeng Qu, Mengjun Hu, Meilong Hu

Titanium bearing blast furnace slag, which contains 20%-30% TiO2, is a valuable secondary titanium resource. Based on the thermodynamics calculation effect of the temperature on the reduction of the slag in vacuum were studied at certain vacuum degrees. The results show that magnesium vapor and silicon monoxide vapor can be obtained at the condition of high temperature and low pressure. The purity of TiC increases with temperature increasing. When the temperature arrives at 1623K TiC can be obtained besides the reductant carbon. XRD result of the powder collected from the furnace cover show that magnesium and silicon in the titanium bearing BF slag leave the slag system during carbothermal reduction in vacuum. From the above it can be concluded that TiC can be obtained from the titanium bearing BF slag and silicon and titanium in the slag can be separated by carbothermal reduction in vacuum and acid leaching.

Jan 1, 2016

By Ki Joo Sim, Sung Beom An, Joonho Lee, Minsoo Shin

Valorization of the electrical arc furnace oxidizing slag by coke was carried out by the reduction of iron oxide in the slag. Since the reduction of iron oxide by solid carbon is an endothermic reaction, supply of heat energy is required. In addition, slag has a low thermal conductivity; traditional fuel injection is not suitable for this reaction. Microwave can be used to supply heat energy to the system. Commercial oxidizing slag was reduced by coke under the microwave irradiation (1.7 kW, 2.45 GHz). The maximum recovery ratio of iron was 87%. In addition, slag composition modification was attempted to use the remaining slag for a mixture in cement clinker. Free-CaO in the slag was successfully suppressed, and the use of the remaining slag as a potential mixture was confirmed.

Jan 1, 2014

By P. Chris Pistorius

An example is presented to illustrate the joint effect of local reaction equilibria and mass transfer limitations, for reactions during ladle refining of steel. The example relies on some of the kinetic principles that David Robertson has employed to quantify many metallurgical processes. In calcium treatment of alumina inclusions in aluminum-killed steels, solid CaS forms as an intermediate reaction product. During subsequent reaction, CaS disappears and calcium aluminate forms; at the same time, aluminum and sulfur dissolve in the steel. Kinetic analysis shows that the rate of this reaction is not limited by mass transfer of dissolved aluminum and sulfur away from the reacting inclusions. The reaction rate is likely limited by transport of dissolved calcium. This example also illustrates the use of FactSage macros for kinetic modeling.

Jan 1, 2014

By Byung-Su Kim

The recovery of elemental sulfur from sulfur dioxide has important implications for coal- burning power plants and nonferrous metal smelters. The thermodynamic analyses showed calcium sulfide to be suitable for recovering elemental sulfur from sulfur dioxide. At the temperatures of 1023 to 1153 K under the sulfur dioxide partial pressures of 5.0 - 60.1 kPa, elemental sulfur from sulfur dioxide was recovered by its reaction with calcium sulfide. The kinetics of this reaction were measured at the same conditions using a thermogravimetric analysis technique. This reaction scheme would be attractive if the coproduct calcium sulfate can be reduced to regenerate calcium sulfide. This is the topic of another paper. At 1073 K under the sulfur dioxide partial pressure of 25.8 kPa, 48 % of the original calcium sulfide was converted to calcium sulfate in an hour. Under the same conditions, 55 % of the regenerated calcium sulfide were converted to calcium sulfate in an hour even after third regeneration.

Jan 1, 1999

By Denise C. R. Espinosa

Rechargeable lithium batteries are one of the most promISIng technology in battery development. Although Li ion batteries have been used as an alternative to the more polluting and less performing Ni-Cd batteries, Li ion batteries have limited life and their disposal is uncertain. It is imperative that valuables from wastes, such as lithium, should be recovered. The main objective of the present work was to characterize secondary lithium batteries for cellular phones. This was done using unit operations of mining processing, x-ray diffraction (XRD), chemical analyses and the rmogravimetric analysis (TG). The unit operations were hammer mill grinding, knife mill grinding, size separation and magnetic separation. After the hammer grinding process, the plastic cases were almost intact, however, they have released the cylindrical lithium batteries themselves and these parts correspond to 70% of the total battery weight.

Jan 1, 2001

By Henrique Kahn

The Anitapolis alkaline massif in southern Brazil underlies a sub circular area of 6 km2. Bore-hole data show a concentric rock distribution, with mafic rocks in the central part and felsic rocks in the border zone. The rocks are covered by talus and weathered material, 30 m thick on average, and very inhomogeneous in composition. Phosphate mineralization associated mainly with two levels of the weathering mantle and with fresh rocks. A preliminary ore-type classification was based on distribution of apatite, feldspar, vermiculite, biotite-phiogopite, calcite, pyroxene, amphibole and analcime, determined by semiquantitative diffraction method. Technological tests performed on eluvial ore samples from three adits resulted in a subdivision of ore-types based on the difference in behavior due to mineral characteristics during mineral pr

Jan 1, 1991

By Sutham Niyomwas

Biomorphic Cellular TiCIC ceramics were produced by vacuum-infiltrating carbon preforms with Ti02 sol and subsequent synthesis by the carbothermal reduction process. The carbon preforms used in the study were obtained by pyrolysis of parawood and neem wood. The effect of infiltration time on the composition and microstructure of the biomorphic TiCIC ceramic was analyzed by X-ray diffractometry and scanning electron microscopy. The biomorphic structure of the TiCIC ceramic is consistent with that of the biotemplate natural parawood and neem wood.

Jan 1, 2008

By C. W. Whitten

Solis from an abandoned Pb battery processing facility were characterized prior to the selection of the extraction technique. Reflected light microscopy and electron beam methods were used to locate Pb-bearing phases and to quantify the compositions of the phases. It was found that the soils are composed primarily of quartz and feldspars with minor amounts of iron and titanium oxides. Lead is primarily present as an oxide or sulfate that is associated with the silicate minerals. Specific phases identified were PbO; Pb02; cerrusite, PbCO3; angleslte, PbSO4; galena, PbS; and magnetoplumbite, 2PbO3Fe2O3; or plumboferrite PbO2Fe2O3?

Jan 1, 1989

By A. Martins, L. Goulart, E. Araujo, R. Batista, A. Costa e Silva

Steel cleanness is of great importance to the performance of almost all steel products. From very clean steel for bearings to long products used in civil construction, processing variables – in special those in steelmaking operations- must be properly balanced to achieve adequate cleanness for the desired performance. With the present complexity of steels as alloy systems, it is not efficient nor appropriate to develop these processes on empirical basis alone. Computational thermodynamics can greatly improve process development to achieve the desired cleanness level at reasonable costs. In this work, examples of these calculations and their applications to real steel processing are presented and discussed. The advantages, limitations and areas in which improvement in these calculations is desired are highlighted and discussed.

Jan 1, 2015

By Fuqiang Zheng, Yufeng Guo, Pengfei Li, Guanzhou Qiu, Tao Jiang, Andrew Yakovlevich Travyanov

Low content of TiO2 and high impurities content of Ca and Mg are the shortcomings of domestic ilmenite. To meet the requirements of the material in the titania produced by chlorination process and titanium sponge industry, enrichment of ilmenite is necessary. In the process of enriching ilmenite, high temperature and reductive condition were beneficial to the formation of anosovite, but the high content of magnesium oxide which was solid soluble in anosovite baffled the following separation. So the effects of pre-oxidation and reductive conditions including reduction temperature, reduction time and hydrogen concentration on the phase composition and metallization rate were studied. The characteristics of reduction samples were analyzed by X-ray diffraction and optical microscope. Results have shown that the reduction product is mainly composed of Fe, Fe(Mg)TiO3 and TiO2 at 1123K, its metallization rate is about 65%,magnesium exists in Fe(Mg)TiO3.

Jan 1, 2015

By Shengli Wu, Wei Huang, Xinliang Liu, Kaifa Zhang

The slagging behavior, the phase of primary blast furnace slag and its transformation law of structure for the single furnace burden were studied in this paper. The results showed that the formation of primary slag was controlled by CaO/SiO2, Al2O3 content, MgO content, reducibility, iron content and porosity of the furnace burden. Fayalite (2FeO•SiO2) was easily formed from acid ferrous furnace burden while kirschsteinite (2(Fe,Ca)O•SiO2) was produced from alkaline ferrous furnace burden

Jan 1, 2015

By I. Hilerio

Chromium Nitride (CrN) thin films were deposited on AISI steel 316 substrates by means of the reactive magnetron sputtering method. CrN films were produced under two different conditions. In the first one, the substrate was heated by a DC source. For the second coating a negative substrate bias voltage was applied. X ray diffraction, quantitative energy dispersion and scanning electron microscope were employed to characterize the two different phases, their chemical composition as well as their microstructure. In addition, a microhardness test was carried out. The results show that a better phase formation of CrN thin films was achieved when a heating source was present (first case). Both coatings presented homogeneous surface. Their compositions show differences even when the gases flowing are the same in composition. Regarding to the hardness test results, there can be found a higher value when using a heating source.

Jan 1, 2009

By Xiang-dong XING, Zhen-yang wang, Jian-Liang Zhang

Distribution behavior of titanium between CaO-SiO2-MgO-Al2O3-TiO2 and hot metal was studied between 1350 °C to 1600 °C. Experimental results indicate that the reaction temperature influenced the activity coefficients of titanium and resulted in the variation of equilibrium constant. Finally, the Gibbs free energy formula of titanium carbothermic reduction was fit out using the thermodynamic model of Wagner and congregated electron phase models.

Jan 1, 2015

By Chen Chen, Wang Yanze, Hong Xin

Furnace superalloy was applied in harsh environment within the erosion of high temperature and oxidizing atmosphere. With plasma powder surfacing technology, iron-based alloy powder was sprayed on the surface of 310S stainless steel to form oxidation layer that increases the oxidation resistance and reduces the cost of materials. With optimum technological parameters, in this paper, oxidation test of 100 hours on iron-based cladding alloy and furnace alloy were carried out at 1200 . The technique of XRF, XRD and EDS were used to characterize composition, oxide morphologies and surface mechanical properties. The results showed that Element composition of cladding layer formed by Plasma powder surfacing was well distributed. Its oxidation weight gain rate of 100 hours was 0.4552g/m2h, belonged to antioxidant level. The oxidation weight gain rate of furnace alloy was 1.4617g/m2h, belonged time-antioxidant level. And on the mechanical comparison test, surfacing alloy is relatively excellent than furnace alloy.

Jan 1, 2016

By Maria das Graças da Silva Valenzuela, Guillermo Ruperto Martin Cortes, Francisco Rolando Valenzuela-Diaz

Bentonites are an important kind of industrial clays with more than a hundred different uses. In the oil and gas industries they are used as thixotropic additives for drilling fluids and also as sorbents for purification of flows and effluents. Due to the mechanical and thermal properties that they exhibit, bentonites will become in a near future important fillers in clay/polymer nanocomposites which could be used in the oil and gas industry for replacement of various metal components. In this paper a chocolate color bentonite from the state of Paraiba in Brazil was characterized by diverse techniques such as XRD, DSC/TGA, surface area, and cation exchange capacity and it was studied its potential use as thixotropic additive for oil and gas drilling fluids and assorbents of oils. The bentonite showed good potential for use in those applications.

Mar 1, 2018

By Lin Li, Xiang Li, Yifang Zheng, Jilai Xue, Jun Zhu

"Al drops and gas bubbles in the anode-cathode space of aluminum electrolysis cell are of great importance for cell operation improvement in metal loss, current efficiency and energy consumption. A direct observation on the Al drop, gas bubble and ultrasound was carried out through a see-through cell. The Al drop immersed into the cryolitic melt was found moving up and down irregularly in the anode-cathode space without electrolysis, which was then completely dissolved into the melt. During electrolysis, the Al drop came to the anode area and reacted with the gas bubbles generated on the anode. Under ultrasound, the gas bubbles were removed from the anode surface while the Al drop was kept on the side of anode. The observed phenomena were useful for technology improvement in reducing the anode-cathode distance or lowering the energy consumption in aluminum electrolysis.IntroductionDuring aluminum electrolysis, aluminum metal drop and anodic gas bubble are in close contact each other within the anode-cathode space, and the interaction between them can produce significant impact on metal loss, current efficiency and energy consumption. The motions of the Al drop and the gas bubble are also related to the dissolution of aluminum metal into cryolitic melt and the cell voltage drop due to the bubble layer covering the anode surface.A number of studies have been carried out using different types of see-through cells, where the dissolving process of metal Al into cryolitic melts (metal fog) in the anode-cathode space was directly observed and photographed [1, 2]. With the similar method, some direct observations on the anodic bubble behaviors with and without ultrasound were performed during aluminum electrolysis [3-6]. However, to our best knowledge, there is no published work on direct observation on the behavior of Al drops and anodic gas bubbles staying together within the same anode-cathode space, as well as the motion and interaction of them in cryolite-alumina melts."

Jan 1, 2011