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By Herbert H. Kellogg

A model of the ISF is described. which reproduces with accuracy the "normal" operation of three industrial furnaces. The model, written in Fortran, is based on detailed heat and material balances, and the concept that the ascending gases reach equilibrium with zinc oxide and with the water-gas shift reaction. "Solution loss" of carbon in the lower shaft, and partial reoxidation of zinc vapor in the upper shaft are also essential features. For prediction of furnace behavior under altered operating conditions (blast rate, temperature, moisture content, oxygen enrichment, or injection of oil or coal through the tuyeres) the model modifies the heat loss, temperature of slag and bullion, amount of reoxidation in the upper shaft and the condenser efficiency to reflect the altered operating parameters. Model predictions for such operating conditions are in reasonable agreement with plant experience.

Jan 1, 1990

By R. Singh, C. Gong, J. Chaudhry

"Metalorganic chemical vapor deposition (MOCVD) is an ideal technique for the deposition of conducting and non-conducting oxide based thin film materials. In this paper we have presented a study of photo assisted MOCVD for the low temperature deposition of a number of oxide based advanced materials. We have used incoherent light sources as the source of optical and thermal energy in our MOCVD system. The vacuum ultraviolet (VUV) and ultraviolet (UV) photons can enhance the surface reaction of the absorbed molecules through the perturbation of the electronic state of binding between the absorbed molecules and the solid surface. Unlike plasma process, no surface damage is expected and high quality materials have been deposited. At a given substrate temperature, the performance of deposited film depends on the lamp configuration.INTRODUCTIONMetalorganic chemical vapor deposition (MOCVD) has become the standard manufacturing technique for the deposition of large area thin films of compound semiconductors. l.(.w-cost, high crystalline quality, atomically clean and sharp interfaces, atomic layer epitaxy, high throughput rates and potential for direct writing are some attractive features of MOCVD. Due to a number of potential advantages mentioned above, MOCVD is considered as an ideal technique for the deposition of various electronic and optical materials for a wide variety of applications. Rapid isothermal processing based on incoherent radiation as the source of optical and thermal energy is emerging as the key low thermal budget (integral of processing time and temperature) processing technique for the fabrication of current and next generation of microelectronic and optoelectronic devices and circuits [1]. In this paper we have demonstrated that the design of the lamp assembly plays an important role in determining the properties of the materials deposited by RIP assisted MOCVD. We have studied the growth rates, structural properties and electrical properties of Y2O3/Si structure. At a given substrate temperature, best results are obtained for the lamp assembly that provides maximum number of VUV and UV photons."

Jan 1, 1994

By David J. Kinneberg, Barbara E. Mangion, Arnold M. Savolainen

Analytical laboratories require a qualitative or semi-qualitative method of determining major and minor constituents in "unknown" samples to select optimal analytical techniques. This is exceedingly important in precious metal assay laboratories where the precision and accuracy requirements are exacting (routinely within 0.02%, absolute basis). This paper describes the use of an x-ray fluorescence spectrometer with a specially designed software package to select optimal analytical procedures and specify relevant analytical parameters. A wavelength dispersive XRF spectrometer is capable of quick and accurate analyses of properly prepared samples without extensive standardization. When coupled with a specially designed software package, this preliminary assay system is applicable to a wide variety of sample types including gold and silver bullion, karat gold and karat PGM alloys, high silver and high copper metallic samples as well as particulate samples of ores and sweeps. The system relieves the assayer of tedious calculations for silver inquartation and proofing, minimizes human error and standardizes selections over time. Most importantly, the system allows for independent verification of final assay results.

Jan 1, 1999

By Rui Mao, Ke-Xin Nao, Jian-Liang Zhang, Xiang-Nan Xu, Meng-Fang Wei

"In this research, fundamental characteristics of dust and sludge containing iron from the dusting system of sintering process, blast furnace, oxygen converter and rolling process in steel enterprise were studied by chemical analysis, X-ray diffraction analysis, optical microscope analysis, scanning electron microscopy analysis, particle size analysis and other analysis means. Development direction of resource utilization for dust and sludge containing iron from steel enterprise was put forward on the basis of above study.IntroductionDust and sludge containing iron for steel enterprise mainly come from the dusting system of sintering process, pelletizing process, blast furnace, oxygen converter, rolling process and other related process. Iron content of dust and sludge is between 30% and 70%, and they also contain certain content of carbon, calcium oxide, magnesium oxide and harmful elements [1-3]. Output of dust and sludge is determined by raw materials conditions, technological processes, equipment configuration and management level. Dust output in sintering process accounts for about 2% to 3% of the sinter production, while dust and sludge from iron making and steel making process respectively take up 3% to 4% of hot metal and crude steel production, and the solid waste from rolling process accounts for about 0.8% to 1.5% of the output of rolled products [4,5]. Dust and sludge contains Fe, CaO, MgO, C and other valuable resources, it will not only result in the waste of resources, but also cause serious pollution to environment ifthe dust and sludge are not recycled. China's crude steel production in 2012 is about 700 million tons and output of dust and sludge containing iron is nearly 60 million tons, so, it is of great significance to have a resource recycling for dust and sludge containing iron from steel enterprise."

Jan 1, 2014

By A. Jakobsson

Studies of the rate of interdissolution in oxide systems in the solid state are of importance in materials processing through the powder-metallurgical route. As there is a need for following the rate of the such reactions continuously, a new method based on high temperature X-ray diffraction was developed. Mechanical mixtures of the oxides were placed in a high-temperature X-ray diffraction unit and the changes in the intensity and position of the peaks with highest intensity for both the components were followed as functions of time. A suitable theoretical model has been developed in order to interpret the experimental data and evaluate the diffusion coefficients. The method was applied in the case of the system MgO-NiO. The results obtained are compared with those obtained by another new method, based on solid-state galvanic cell technique with calcia stabilized zirconia electrolyte, developed in the Department of Theoretical Metallurgy. The advantage of the present techniques to monitor the progress of the reaction continuously make them suitable for computer control of such processes.

Jan 1, 1995

By Raymond M. Coveney

Bedded sulfide ores in Cambrian Chinese black shales typically contains at least 2% Ni, 4.5% Mo, 1% As and 0.2% Se. Thin laminae and replaced on colites from the ore contain intimate mixtures of fine-grained Ni-rich sulfides and jordisite complicating ore treatment. The ores contain abundant jordisite, vaesite, nickelian pyrite, and barite and lesser amounts of sphalerite, gersdorffite, millerite, tennantite, fluorite, chalcopyrite, and HgSe (probably tiemannite). At present only ores that are sufficiently rich (>4.5% Mo) for direct roasting are mined and treated to produce, ammonium molybdate. The ores contain Pt, Pd, and Au in amounts totaling up to -2.5 ppm, but these are not recovered.

Jan 1, 1993

By C. J. Malek

The CONTOP® smelting cyclone technology is a large-scale and time-proven method which in combination with other technologies (grinding, drying, pyrolysis, etc.) provides for a cost- efficient and ecological disposal of a wide range of waste materials from industry and households. In this report the basic principle of smelting cyclone technology will be explained first. Subsequently, the paper will discuss substantial concepts for the recovery of various remainders.

Jan 1, 1996

By Douglas K. Modrow

In the fall of 1993, construction was completed on a state of the art industrial waste water treatment plant at Asarco's East Helena Lead Smelter. Purpose of the plant was to remove arsenic and metals using hydroxide precipitation. Completing of the plant culminated a lengthy process of laboratory bench-scale test work, engineering, construction, and Environmental Protection Agency (EPA) oversight. Unfortunately, the effiuent requirements for the plant were made significantly more stringent as construction was rearing completion. As a result, optimization activities were initiated to determine and implement measures to substantially improve effiuent quality so the new discharge limits could be met. These activities consisted of acquiring a thorough understanding of process chemistry and plant operations, and developing simple, practical methods of automating unit operations associated with the treatment plant. Implementation of these modifications in the second half of 1996 will not only significantly improve the constancy and reliability of treatment plant operations, but also result in operating cost savings and reduced need for increased operator attention at capacity flows, plus allow the treatment plant to meet the new discharge limits.

Jan 1, 1996

By Cheng Pan, Qiugang Yuan, Xuewei Lv, Mei Liu, Enguang Guo

Land-based nickel resources include nickel sulfide and nickel laterite. With the consumption of high grade nickel sulfide, use of nickel laterite has received more and more attention. The mineralogy and sintering behavior of limonitic nickel laterite with high iron and low nickel and silica was studied to offer technical support for producing ferronickel through sintering–blast furnace route. The mineralogy results showed that the main phases in this kind of nickel laterite are goethite (FeO(OH)), gibbsite (Al(OH)3) and NiFe2O4. The TGA (Thermogravimetric Analysis) and DSC (Differential Scanning Calorimetry) revealed hydroxide minerals in addition to absorbed water. After the sintering experiments the chemical composition, phases present (XRD analysis) and physical properties of the sinter were studied. The content of FeO in the sinter increased with increasing basicity up to 1.3, and then decreased with further increase in basicity. The yield of sinter increased (from 73% to 80%) with increase in the basicity from 1.1 to 1.7, and then the yield decreased with the further increase in basicity. Mg(Ni)(Fe,Al)2O4 is the main phase in the sinter while MgCaSiO4 and Fe2SiO4 is the main binder phase when the basicity is 1.1~1.5, and MgCaSiO4, Fe2SiO4 and SFCA is the main binder phase when the basicity is 1.7~2.1.

Jan 1, 2014

By C. Palacios

The Plant, which was started up in April 1970, was originally designed for a capacity of 40.000 ton of cathodes per annum, using 12 sections, containing 408 cells. Since then the addition of another 8 sections containing 280 cells and using the Reverse Current System has made possible the increased output of 109.000 ton. The quality of the cathodes produced is excellent. The extension of the Electrolytic Refinery, by the introduction of the Reverse Current System, has been a great success and no problem has arisen in the new equipment or in the modifications carried out in the plant. The operation of the plant has improved due to better control procedures.

Jan 1, 1976

By Young-Chul Kang

The Onsan Copper Smelter of LG-Nikko Copper Inc. is a unique plant, which has been operating two smelting processes since 1998. The operation of the first one was started in 1979 with a capacity of 80,000tpy of copper in concentrates utilizing Outokumpu flash- smelting technology. The other one was started in 1998 based on Mitsubishi continuous process with a capacity of 160,000tpy of copper in concentrates. Through several expansion projects, the total smelting capacity of both processes is expected to reach 430,000tpy of copper in concentrates towards the end of 2002. This article describes operation advantages of having two different processes at one plant and comparative operation results in terms of productivity, impurity distribution, energy consumption and environment issues and etc?

Jan 1, 2003

By Ronald K. Riddle

The processing of lateritic ores in rotary drying and preheating/pre-reduction systems has historically been plagued by problems associated with significant dust generation. These problems include handling issues, kiln capacity limitations, negative impacts on furnace stability, a reduction in nickel recovery and higher operating costs. The dust is formed in the rotary devices during heating and tumbling due to the following three mechanisms: (I) mechanical dccrepitation of the ore as a result of tumbling and attrition, (2) thermal decrepitation during rapid vaporization of internal free and bound water, and the (3) loss of free moisture which functions as a binder. This paper investigates the causes of dust formation, provides methods to reduce dust carryover from the rotary devices, and finally offers methods to recover the dust in the existing pyrometallurgical process. Keywords: Laterite, Drying, Rotary, Dust

Jan 1, 2004

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By Ryokichi Shimpo

Much amount of sludge is produced from the wastewater treatments in surface finishing industry. There are many problems for the abandonment of the sludge because of the high water content and heavy metals included. It is often observed that hexavalent chromium, which is toxic, is generated in the course of heat treatments of the sludge for reducing its amount by dispersing water. In this study, conditions of the sludge calcinations for reducing water contents have been examined. Maximum hexavalent chromium generation was observed in the temperature range around 773 K, at which most of the crystallization water decomposed from the sludge. When the heating temperature became higher than 1173 K, the amount of the hexavalent chromium extracted from the calcined sludge became as low as 10 mg/kg sludge. When the sludge was heated with iron oxides, FeO or Fe203, iron ferrite has been synthesized which may be used as a magnetic material. The amounts of hexavalent chromium generated in the heat treatment with iron oxides were not much different from those without iron oxides.

Jan 1, 2003

By A. V. Tarasov, V. M. Paretsky

"The knowledge of the true phase composition of the liquid slag is a very important problem, mastering of which grants the possibilities for the scientifically founded choosing of the decoppering method of the autogenous smelting slags. The investigation using different methods of the phase composition of the flash quenched autogenous copper melt's slags has shown, that the most effective method of the slags' decoppering during smelting with the white matte production is the flotation of the recrystallized slags. In this work the authors posed the problem to realize the slags quenching with the rates similar to those, which are used in the modem investigations devoted to the flash quenching of the ironcontaining alloys, with the subsequent study of the quenched samples using the Mossbauer spectroscopy methods in order to establish the connection between the liquid slag's structure and the metals losses with the slag."

Jan 1, 2000

By Kumar M. Lyer

Residence time distribution (RTD) of light and heavy liquids in a pyrometallurgical channel reactor was mathematically modeled by representing the reactor as a combination of ideal reactors. Cold model studies simulated the counter-current flow of slag and matte (or metal) with high-strength bottom gas injection. The experimental variables include flow rates, heights, density and viscosity of the two liquids; gas flow rate; injector diameter; and distance between injectors. The experiments covered a wide range, of the appropriate dimensionless parameter, including conditions in ferrous and nonferrous extractive metallurgy. Dispersion modeling studies were also carried out to determine the degree of backmixing. Results indicate that the degree of backmixing in the channel reactor for various operating conditions corresponds to that for 3-20 perfectly mixed reactors in series.

Jan 1, 1993

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 Musa Karakus

Reflected light microscopic (RLM) examination of dust particles from lead and copper smelters can effectively characterize their mineralogy, texture, and origin. Scanning electron microscopic-energy dispersive spectroscopic (SEM-EDS) analysis provides confirmation of the optical identifications and chemical data on the phases. Studied lead smelter dust samples were from the: I) blast furnace, 2) sinter plant scrubber, 3) sinter plant crusher, 4) dross furnace, and 5) refinery. Phases identified included galena fragments, melted PbS, metallic Pb and Cu, Cu-Ni, Cu-Zn, Zn-Ag, Zn-Cu-Ag, Ni-Cu-Sb, and Ni-Cu-Zn-Ag metal alloys, Ni-sulfide, Cu-sulfide, and Cu-Pb-sulfide dross .phases; slag and sinter particles, coke fragments, unreacted original feed phases: pyrite, chalcopyrite, sphalerite, siegenite, bravoite; and oxidized particles: iss, bornite, chalcocite, covellite, magnetite, hematite, and goethite. Dust from a secondary copper refinery were found by RLM and SEM to consist of tenorite, cuprite, cassiterite, two silicate phases. Magnetite, hematite, Fe-Al-Cr-Mg spinel, periclase, forsterite, and wollastonite were derived from the furnace linings during initial cleaning.

Jan 1, 1992

By F. D. S. Marquis

An investigation of the mechanisms of formation of two types of porosity-primary and secondary-their characterization, evolution during processing, and effects on the mechanical behavior (fracture, fatigue, and failure) of 7X50 and 2X24 alloys has been conducted. The mechanisms of formation of three forms of primary or cast porosity were investigated, and each form was characterized: (a) macroscopic shrinkage porosity-MSP); (b) microscopic interdendritic porosity (MIP); and (c) hydrogen gas porosity (HGP) or primary hydrogen porosity (PHP). The mechanisms of formation of four forms of secondary or thermal/thermomechanical porosity were investigated, and each form of porosity was characterized: (a) high temperature oxidation (HTO). internal hydrogen precipitation (IHP), or secondary hydrogen precipitation (SHP); (b) preheating blistering porosity (PBP); (c) eutectic melting porosity (EMP);and, (d) dissolution micro void formation (DMF). The evolution and interactions of the primary and secondary types of porosity (w.ith special emphasis on PHP and SHP) during industrial and laboratory processing and their effects on the fracture and failure behavior of both types of alloys (with special focus on fatigue crack initiation and propagation) were investigated.

Jan 1, 1996

By Hong Liang-shi

Olivine lithium iron phosphate (LiFePO4) is considered as one of the most promising materials for lithium-ion secondary batteries because of its high theoretical capacity, low cost, good safety, benign environment and good cycle performance. In this paper, carbon-free and/or carbon-coated olivine lithium iron phosphate composite ultrafine powders were successfully synthesized from aqueous precursor solutions of (NH4)2Fe(SO4)2?6H2O, H3PO4 and LiOH?H2O by co-precipitation method. The obtained LiFePO4 or LiFePO4/C powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Their electrochemical performance was investigated in terms of cycling behavior. As confirmed by X-ray diffraction and scanning electron microscope, the material obtained by co-precipitation within the temperature range of 60ºC to 100ºC and then followed by moderate heat treatment are a single-phase olivine LiFePO4with the particle size of about 300nm. An improved carbon-coated olivine LiFePO4/C material was prepared by adding conductive carbon materials, such as glucose, activated carbon and acetylene black, into the precursor. The carbon dispersed in the materials increases the electronic conductivity of LiFePO4/C composite, and consequently, leads to high rechargeable capacity of the material. The carbon-coated material with carbon amount of 7.64%wt obtained from glucose has the first discharge capacity of 150.3mAh/g at the rate of 0.1C and 129.3mAh/g at the rate of 1.0C, respectively. After cycled for 50 times, the capacity retention rate is 95.13% at the rate of 1.0C in the voltage range of 2.5 to 4.3 V vs. Li/Li+.

Jan 1, 2006