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By Jiang Diao, Yong Qiao, Xuan Liu, Tao Zhang, Bing Xie

Adding CaO into the vanadium extraction converter is an effective way to decrease the dephosphorization burden in subsequent steelmaking process. The crystallisation process of spinel is one of the most decisive factors in the subsequent extraction. The theoretical calculation results show that the temperature of the peak total crystallization rate will decrease 5K with basicity increasing 0.1. The relation between cooling conditions and grain size of spinels is also discussed. It is found that low cooling rate and high basicity benefit spinel crystal growth. And the non-isothermal crystallization kinetics results indicated that the restriction factors of spinel growth is that solid crystals accept new components from liquid-solid interfacial. While the sample was cooled down to 1250 (1523K) at cooling rate of 5K/min, the crystal growth is consistent with Ostwald coarsening grew up law, and controlled by diffusion of particle.

Jan 1, 2016

By Daowu Yang, Zhuo Ren, Hui Liu

"In this paper, the photochemical catalysis degradation effect of photocatalyst obtained by charcoal-supported nano TiO2 (nano TiO2 / charcoal) on the formaldehyde in the air was studied. The influences of the nano-TiO2 loading and the photoreactor structure on the efficiency of photochemical catalysis degradation of formaldehyde was reviewed.The nano - TiO2 / bamboo charcoal adsorption of formaldehyde, as well as the influences of a certain amount of formaldehyde after adsorption on its photochemical catalysis effect were discussed. The sol preparation process of Ce-doped nano-TiO2 was described. Experimental results indicated that: the surface of bamboo Charcoal still has a strong formaldehyde adsorption capacity after Supported by Nano TiO2.After adsorbing formaldehyde, the photochemical catalysis degradation efficiency of formaldehyde of the catalyst at a steady state is basically the same with new prepared catalysts’. When the thickness of the catalyst layer of the multi-ladder-type structure photoreactor is 2mm, the interval is 20mm, the absorption efficiency of formaldehyde of Nano- TiO2 / bamboo charcoal is the best . Nano-TiO2 undoped Ce responded with no degradation of formaldehyde after 2 hours, while the degradation rate of formaldehyde of the Ce-doped nano- TiO2 reached 15% 2 hours late, and the formaldehyde decontamination of the equipment reached 94%.IntroductionEmerging out of home decoration in the distribution of formaldehyde, benzene, ammonia and other indoor pollutants have been proved to be very harmful to the human body. Photocatalysis can eliminate air pollutants, in particular, can effectively degrade the air volatile organic compounds, it is a new method of air purification developed in recent years. the biggest advantage of photochemical catalysis degradation is green, this method can be available at normal temperature and pressure to degrade formaldehyde and other organic matter into carbon dioxide and water without secondary pollution.Nano-TiO2 have become the most studied photocatalyst due to its stable, non-toxic harmless, superior photochemical catalysis properties [1]. Initially nano-TiO2 powder was used as a photocatalyst, but it’s difficult to recover and easy to wear and tear [2,3]. Later, the TiO2 was used in the form of film loaded on some carriers, such as glass beads [4]. As the photochemical catalysis reaction occurred on the catalyst surface, only the organic matter adsorbed on the catalyst surface can be degraded, so the catalyst was requested that must have a strong adsorption. Combined the adsorption properties of bamboo charcoal and the photochemical catalysis activity of nano-TiO2 together. Made the photocatalyst by loading the nano-TiO2 on bamboo charcoal to degrade organic matter in the air. Nano-TiO2 semiconductor photocatalyst has a strong catalytic oxidation due to the photo generated hole of the surface [5,6],and has a potential application. Some studies have shown that nano-TiO2 photocatalysis activity can be increased by doping certain metal ions [7,8].The aim of our work in this study was to use bamboo charcoal load Ce-doped nano-TiO2 photochemical catalysis oxidation to degrade formaldehyde,and design a multi-ladder structure photoreactor, also prove the availability of the device from the theoretical and experimental."

Jan 1, 2011

By Masatoshi Ogasawara

Saganoseki smelter & refinery operated two flash smelting furnaces, producing a combined 330,000 metric tons per year (hereinafter mtpy) of copper. In 1996, however, it successfully shifted to a single furnace operation while maintaining production at the same level. Since then, the production capacity has been further increased to the present 470,000 mtpy by technological improvements. Also, in order to reduce the converter load which represents a bottleneck in efforts to increase production, the matte grade was gradually increased and currently runs at 65 to 66% attaining the low copper content in the slag (hereinafter slag loss) of 0.7 to 0.8%. This paper introduces some improvements, recent operation results and thermodynamic analyses.

Jan 1, 2003

By Fathi Habashi

During the recovery of copper, nickel, zinc, and lead from their sulfide ores, large amounts of sulfur dioxide are generated. A fraction of this gas is captured and transformed into sulfuric acid and liquid SOl and the remainder is emitted to the atmosphere. Numerous proposals were made to solve this problem. Hydrometallurgy offers the only valid solution by which elemental sulfur instead of sulfur dioxide can be produced. Sulfur can be easily stored, transported long distances, or transformed into S02 and H2S04 when desired.

Jan 1, 1996

By Zhang Chuanfu, Li Shixiong

"In the electrolysis electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, with the increase in cathodic over potential the reducing rate of metal and the cathodic current efficiency increases and the deposit becomes more compact and smooth. According to this principle, a method and equipment of the auto-control of electrolyte quality is invented. The industrial application shows that this method turns the experienced operation into auto-control. The quality and quantity of metal is improved greatly and the consumption of electric energy is reduced.In the electrolysis, electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, usually organic additives are added according to the state of cathodic deposit according to experience. This traditional and experienced operation, often lead to that the quality of additive is not optimum which affects the quality and quantity of metal and increases the consumption of electric energy. To counter the controlling problem of the quantity of additive, the authors have invented a corresponding equipment of the auto-control of electrolyte quality [1], it has found application in industrial practice."

Jan 1, 2000

Laminated ceramics have received widely scientific and commercial attention because their properties, such as mechanical properties and electrical properties, can be tailored by adjusting the structure, thickness and composition of the different layers. For example, ferroelectric Bi4T13O12 (BIT) which has a positive temperature coefficient of dielectric constant (TE) can be used to modify the negative of typical microwave dielectric ceramic BaNd2Ti4O12(BMT). However, BaNd2Ti4O12/Bi4Ti3O12/BaNd1Ti4O12 (BNT/BIT/BNT) laminated ceramics could not be prepared by the general method because the optimal sintering temperature of BaNd2Ti4O12 ceramic (around 1350°C was much higher than that of Bi4Ti3O12 ceramic (around /1100°C). in this research, a new method of spark plasma sintering (SPS) combined with post-sintering was successfully proposed to prepare BNT/BIT/BNT laminated divided proposed to prepare ceramics. It was divided into three steps. In first step, the BaNd2Ti4O12 ceramics were prepared by conventional sintering method. In second mop, the calcined and pre-pressed Bi4Ti3O12 powders were sandwiched between BaNd2Ti1O12 ceramic pellets and spark plasma sintered at 900'C for 10min to synthesize BNT/BIT/BNT composite ceramics. In the last step, a post-sintering was employed to reoxidize the partially reduced BNT/BIT/BNT composite ceramics. The results of scanning electron microscopy (SEM) and electron probe mircoanalysis (EPMA) showed that BNT layer and BIT layer were well bonded and no significant interfacial infiltration between them was observed. The sandwiched BNT/B1T/BNT ceramic with 10.7% BIT in volume has a dielectric constant of 92.8, a low dielectric loss of 0.0068 and a small temperature coefficient of dielectric constant v/35 ppm/C at 1 MHz.

Jan 1, 2003

By Paykan Safe

This paper reviews various process off-gas cooling options available for sulfide smelting processes. Advantages and disadvantages of each, system are discussed along with the selection criteria for a reliable and cost effective :system. Various systems are presented to demonstrate typical process parameters for smelter off-gas handling systems and to outline operating difficulties associated with each system:

Jan 1, 1998

By Vincent Canaguier

Methane is increasingly considered as a promising reductant for metal oxides, including chromite. To assess the possibilities of such reduction route, the gas-solid reactions between Ar–CH4–H2 gas mixtures and synthetic chromites are studied between 950 and 1050 °C. The influence of Mg and Al additions on the reduction-caburization of (Fe,Mg)(Cr,Al)2O4 solid solution is investigated thermodynamically, structurally and kinetically. The product phases are examined by x-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). The reaction rate is derived from real-time exhaust gas measurements and post-reaction product analyses such as oxygen analysis. Kinetic models are proposed based on the product phase morphologies and confronted with the empirical data.

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 Gordon D. Jarvinen

Polymer Filtration (PF) Is an innovative, selecthle metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of, Industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to 'aqueous streams from nuclear materials processing and electroplating operations will be described.

Jan 1, 1999

By B. S. -J. Kang, M. A. Alvin, J. M. Tannenbaum

"A load-based micro-indentation technique has been developed for damage assessment and non-destructive spallation detection of TBCs at room temperature. This micro-indentation technology has been further extended to the development of a high temperature (HT) test methodology. Elastic modulus calibration tests performed on Hl 3 Tool Steel to 500°C and Haynes 230 at 1000°C displayed excellent agreement with reported values. Moreover, indentation creep tests of Haynes 230 at 1200°C were found to be in agreement with known creep exponents as well. Finally, a HT thermal flux indentation apparatus was assembled for conducting TBC turbine component testing under high temperature moisture-containing environments (= 50% steam with controlled gas content temperatures up to 1250°C). Description and design considerations of this test apparatus are discussed. Preliminary tests of ReneN5/MCrAlY/APS TBC coupons in steam/air environments with in-situ HT micro-indentation testing are conducted. Furthermore, the coupon is removed and examined for damage assessment at periodical intervals.IntroductionLoad and depth relationships acquired throughout the indentation process provide insight to material mechanical properties such as elastic modulus and hardness. Unloading segment analysis of these load displacement curves are utilized in the acquisition of a material's elastic properties. Yet, indentation tests are complex processes involving contact mechanics, material nonlinearity and even fracture mechanics. Thus exact analytical solutions for these processes are difficult to obtain. As a result, much of the current knowledge regarding the indentation process has been acquired through experimental methods and finite element simulations. Initial efforts by Tabor resulted in the application of spherical indentation to obtain post-yielding stress/strain relationships [1]. Soon thereafter, analytical load-depth relations for elastic indentation were developed [2], yet it was Lure who further derived the explicit relationships for both spherical and conical indenters [3]. Improving upon this, these interactions were later extended to indenters with various geometries by various researchers [ 4]. Additionally, by establishing the linearity of the initial unloading slope within the load-depth curve, a relationship between elastic indentation depth, maximum load, unloading slope and indenter geometry was established [5]. From this a theoretical method by which elastic modulus could be determined was established."

Jan 1, 2011

By J. W. Matousek

Cobalt behavior in pyrometallurgical processes is traditionally analyzed using slaglmatte distribution coefficients as functions of matte grades or matte iron contents. L(s/m) = (%Co) I [%Co] = f [%CuNi] or f [%Fe] The method is inconvenient to use in predictive mass balance work because of the interdependence of assays and mass quantities. An alternative procedure is proposed based on cobaltliron ratios for slags and mattes: Js = (%Co) / (%Fe), Jm = [%Co] / [%Fe], and J, = b + m [Jm]

Jan 1, 1993

By Luis W. Pommier

The developed processes, the subject of this paper, extract the hydrocarbons, halogenated organic compounds and metal contaminants from hazardous soils, rendering them non-hazardous and ready to be placed back on the ground. The processes first segregate a non-contaminated fraction from the contaminated soil. This initial task is performed using available minerals processing technology: sizing, gravity separation, magnetic separation, froth flotation, etc. The remaining contaminated fraction, is submitted to two leaching operations for the removal of organic and metal contaminants, whenever both are present or to a single leaching operation if only one type of contaminant is present. The decontaminated soil fraction is mixed with the non-contaminated fraction and is placed back on the ground. The leaching liquors, used at neutral pH, are non- hazardous. After decontamination the liquids are processed to extract the contaminants, now valuable materials, for commercialization. Organic contaminants are removed by distillation of the solvents. The metal contaminants are precipitated in their oxide form. In both cases the regenerated solvents are recycled. The decontamination processes are economically competitive with transportation and disposal of the soils to permitted facilities for hazardous materials, and most importantly the developed processes remove the liabilities from the Responsible Parties. The law establishes that these liabilities do not disappear with either fixation nor with transportation and disposal since the environmental liabilities are of the ? cradle to grave? type.

Jan 1, 1994

By Cynthia Belt

"Energy management is critical to aluminum processing given the high energy requirements of melting and processing aluminum. Energy costs have always been a high percentage of the total production costs within this industry. Energy management at many plants relied on better technology that many times required high capital. As carbon management has grown in importance and project payback becomes more critical, a larger view of a plant's process is required. This paper looks at the energy requirement due to current typical practices in overall product recovery, metal loss, utilization, and technology to understand potential methods of reducing overall energy within a plant and within the aluminum processing industry.IntroductionFor many companies that process aluminum, energy is a major portion of their costs that can surpass the cost oflabor. Aluminum processing can include secondary processing of scrap and prime aluminum into sows and/or molten aluminum or casting aluminum by various methods such as direct chill, continuous casting, low or high pressure casting, mold casting, and extrusions. In the case of this paper, we are considering only plants that include the melting process as a portion of their process. The process of melting aluminum takes energy. In most cases, the aluminum must then be heat treated one or more times. Post processing of the aluminum includes rolling mills used for making sheet, extrusion lines, and machining such as saw cuts, drilling, or surface finishes that all take additional energy.While these high energy costs directly affect the profits of the company, energy management within the metals industry is still not widespread. A co=on misconception is that the solution to high energy costs is high cost capital equipment. While state-of-the-art equipment can certainly improve energy efficiency, it is not the only solution. To obtain a truly energy efficient plant, several directions needs to be addressed through an energy management thought process with a wider scope. Impact on potential savings is possible through: product recovery, metal loss, utilization, and new technologies. An understanding of the potential costs and savings from these means is important. Several of these methods provide low cost approaches to saving energy.The background data used in this paper is not a random sample within aluminum processing but yearly averages from various plants in different aluminum processing industries. As is normal in this industry, the plants have been under different corporate management over the years with different strategies for energy management. This data is not meant to be accurate for the entire industry but to suggest areas for energy efficiency work."

Jan 1, 2012

By Varuzan Kevorkijan

A new method for faster production of functionally graded metal-ceramic laminates is based on reactive pressureless counterflow infiltration/penetration of a ceramic substrate with two different metallic infiltrants. The porous or dense ceramic preform is pressurelessly infiltrated or penetrated from one side by the first metallic infiltrant to the desired cross section of the preform, producing the top layer made up of the solidified infiltrant and the underlayer consisting of reactive infiltrated preform. The partly infiltrated perform is then completely infiltrated starting from the other side by the second metallic infiltrant, in this way fabricating the internal layer, consisting of the ceramic perform infiltrated with the second infiltrant and the bottom layer formed by the solidified second infiltrant. Systems already investigated include carbide, nitride and boride ceramic performs infiltrated with aluminum and magnesium alloys.

Jan 1, 2003

By E G. Prado

We have confirmed on bench scale the removal of chlorides and alkalies (+95%) and over 2/3 of the zinc, lead and cadmium from EAF dusts. This has been achieved with arrononium acetate solutions alone, or with combinations of water wash, amonia-ammonium carbonate and ammonium acetate solutions. Also confirmed are the process routes for the recovery of the aforementioned elements into marketable products. The technology involves the complete recycling of the reagents. The FAF residue is returned to the electric furnace without risk of impurities buildup. Commercial scale testing with the recycled dust was satisfactory, including quality of the slag and its behavior during the melting stage. A cursory feasibility evaluation is presented.

Jan 1, 1994

By L. Sh. Tsemekhman

The results of laboratory, large-scale laboratory and commercial scale investigations regarding the process of slag melts cleaning by oxidizing-reduction gas mixtures with a wide range of Po2 and the use of matte of various compositions as an extracting phase are presented. The copper, nickel and cobalt behavior during the cleaning process has been studied based on SEM and x-ray Microprobe of the quenched slag melts. The general cleaning mechanisms have been found. On the basis of the obtained data the most efficient cleaning methods have been proposed.

Jan 1, 2003

By Bo Jiang, Jiusan Xiao, Hongmin Zhu, Kai Huang, Shuqiang Jiao

Carbothermal selective reduction of simulative titanium slag and various titanium raw materials were presented and SiO2 was found to be partially reduced, forming a series of Fe-Si alloys during the process. Thermodynamic analysis of the selective reduction between TiO2 and SiO2 was performed using HSC 6.0 software, then a series of equilibrium experiments were designed and presented. The activity of Si reduced from SiO2 was affected by the presence of Fe reduced from FeOx and the generation of Fe-Si alloys, promoting the reduction of SiO2 in the whole process. The results of experiment are in great accordance with the calculated data obtained from thermodynamic analysis.

Jan 1, 2016

By Tianming Sun, Gabriella Tranell, Ragnhild E. Aune, Mark William Kennedy

Rare Earth Elements (REEs) are critical for the production of many advanced materials and products. Mining and primary production of REEs are generally associated with significant environmental impacts. By recovery of REEs from secondary sources, through recycling or as a byproduct, the adverse environmental impacts may be partly avoided. In the present study apatite concentrate originating from iron ore beneficiation done by LKAB in Kiruna, Sweden, is explored as a possible source for REEs. The composition and distribution of the REEs within the concentrates are studied using ICP-MS, XRD and SEM-EDS/EPMA, as well as the melting point and heat of fusion using DTA-TGA-MS. The behavior of the material during melting has also been studied through wetting and slag saturation experiments. The overall aim of the study is to evaluate the implications for future smelting experiments aimed at concentration and recovery of the REEs.

Jan 1, 2015

By Jian Li, Guo Chen, Bingguo Liu, Hongying Xia, Jinhui Peng, Libo Zhang

"Decomposition of ammonium tetramolybdate to prepare Mo03 using silicon carbide crucible in microwave fields was investigated. The results were analyzed Using TG-DTG and X-ray diffraction. Meanwhile, the effects of heating rat, material thickness, socking time, socking temperature on the structure of preparing Mo03 were studied. TG-DTG curves show that the decomposition process of ammonium tetramolybdate is only one stage, in the temperature range 300-350°C, whose begin to decompose when temperature increases beyond 300°C. The molybdenum trioxide was prepared by thermal decomposition. The quality ofMo03 was not affected under the heating rat is 12°C/min. It was beneficial for decomposition ratio with the lower material thickness, longer soaking time, and higher soaking temperature. XRD curves showed that it is viable method for preparation of Mo03 by decomposition from ammonium tetramolybdate in microwave fields.IntroductionMolybdenum is widely used in national defense, aviation, industrial and agricultural production as rare refractory metal. Molybdenum trioxide is vital raw materials for the process of preparation of molybdenum. The traditional production technology of molybdenum oxide is that ammonium tetramolybdate is calcined in rotary kiln or 4-tube furnace [J,2J. But the longer production time, the higher production cost, the lower furnace thermal efficiency, and bigger the energy consumption, especially the powder is easy to leak, the working environment is poor by using rotary kiln [ 3 l _ The particle of molybdenum oxide is non-uniform by using 4-tube furnace because of the uneven temperature of every tube and the poor exhaust of boat bottom [4l _ However microwave heating is quick and uniformity, it is a meaningful research that the microwave is used in the process of calcining ammonium tetramolybdate."

Jan 1, 2013