Search Documents

By Glenn Stevens

After 40 years of operation with the original design, Pan Pacific Copper determined it was necessary to rebuild the Saganoseki Flash Smelting Furnace to continue safe operation. The original design employed a rigid steel frame, which, through hearth growth, led to severe distortion of the frame. Contributing to the continued growth of the hearth were thermal cycles that occurred during the government mandated annual shutdowns. Hatch designed a unique sprung bound, pivoting binding frame to maximize crucible size within the existing furnace footprint, while integrating the PPC designed cooling jackets. The bound system maintains tight brick joints, while the new conductive hearth design with integrated bottom cooling produces a protective freeze layer to accommodate higher furnace throughput. Minimization of furnace downtime for the rebuild was achieved through effective construction planning, highly trained contractors, and through an efficient start-up and ramp-up to full production.

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 Masanori Abe, Yoshitaka Kitamoto, Kazuhiro Nishimura

"Ferrite plating is a chemical processing which utilizes Fe2+ - Fe3+ oxidation to synthesizing polycrystalline films of ferromagnetic spinels (MFe20 4, M = Fe, Co, Ni, Zn, Al, Cr, TI, etc:) directly from an aqueous solution at 24 - 100°C. This low temperature process allows us to fabricate new ferrite film devices on · substrates of such non-heat-resistant materials as plastics, GaAs integrated circuits, and biomaterials. Synthesized from an aqueous solution the ferrite plated ·films are highly biocompatible. Thus various magnetic device and biomedical applications have been proposed and realized using ferrite-plated films. Ferrite-encapsulated polymer microspheres are applied to antibody carries for enzyme immunoassay, and also to toners/carriers for photocopying. Perpendicular magnetic recording media utilizing plated CoNi ferrite films are proposed. The low-temperature synthesized films of NiZn and Co ferrites are potentially used as soft-magnetic and/or insulating layers, respectively at high/microwave frequencies.IntroductionFerrite plating is a processing which facilitates the formation of crystalline spinel ferrite films with various compositions, (Fe, M)30 4 (M = Fe, Co, Ni, Zn, Al, Cr, TI, etc.), directly from an aqueous solution at 60 - 100°C [1]. This opened the door to fabricating novel ferrite-film devices using substrates of such non-heat-resistant materials as plastics and GaAs integrated circuits [2-4]; conventional ferrite film preparation techniques such as sputtering, vacuum evaporation, MBE, LPE, etc., require high temperatures(> -600°C) for crystallization of ferrites, which deteriorates the non-heat-resistant substrates. Recently we extended ferrite plating to be preformed at room temperature [5, 6]. This enables us to use as substrates such organic materials as biomaterials (e.g. enzymes) having very low heat-resistance."

Jan 1, 2000

By Mariane Costalonga de Aguiar, Carlos Mauricio Fontes Vieira, Sergio Neves Monteiro

"This work evaluates the effect of incorporation of an ornamental rock waste into an industrial clayey body used for roofing tiles fabrication. Formulations with 0, 10, 20 and 30 wt.% of waste were prepared by replacing the sand in the industrial clayey body. The plasticity of the formulations was determined by the Atterberg limits. Specimens were fabricated by 18 MPa press-molding and then fired from 850, 950 and 1050°C. The specimens were tested to determine the water absorption, linear shrinkage and three points bending flexural strength. The results indicated that the waste improves the extrusion performance of the clayey body by decreasing its plasticity. The use of the waste was beneficial to the water absorption and mechanical strength of the fired clayey ceramic at 1050°C.IntroductionOrnamental rock is a natural resource available in the municipal area of Santo Antonio de Padua and located 150 km from the city of Campos dos Goytacazes, northe of state of Rio de Janeiro, Brazil. Intense industrial activity related to ornamental stones, especially gneisses, is traditionally occurring in the region. After mining, the flagstone is submitted to sawing to obtain blocks and then, after a manual operation, the final products are small flagstones [1,2]. During the sawing operation, a sludge composed of water and fine particles of rock is generated. A monthly production of 1000 tons of ornamental rock waste is estimated to be produced at Santo Antonio de Padua. The final disposal of this waste has brought serious environmental problems. Since most industries do not have an adequate sludge treatment, the waste is contaminating the soil and underground waters as well as obstructing rivers and lakes.Ceramic bodies industrially fabricated in the municipal area of Campos dos Goytacazes, 280 km from the city of Rio de Janeiro, are still empirically elaborated using a mixture of local clays. These clays are predominantly kaolinitic mineral, associated with high plasticity. Due to the excessive plasticity of the ceramic bodies, it is common to have dimensional defects in the final products after the drying and firing processes. Moreover, the kaolinitic structure and the presence of aluminum hydroxide confer a refractory behavior to the local clays. This impairs sintering during the firing operation. In the case of clay ceramics for civil construction, this results in greater porosity associated with elevated values of water absorption [3,4]. To avoid this problem, it is necessary to reformulate the ceramic body composition. The addition of both non-plastic materials to reduce plasticity and fluxes to condition the refractoriness is a possible alternative."

Jan 1, 2011

By Bhagyadhar Bhoi, Chitta Ranjan Mishra, Hara Prasanna Mishra

"In the Sukinda Valley of Orissa, India, the total quantity of nickel ore reserves comprising of both lateritic and chromite over burden(COB) have been estimated at around 231 million tonnes containing 0.3 to 0.9% Ni. While mining of one tonne of Chromite ore, around 6-7 tonnes of chromite over burden are removed. These overburden materials are disposed as waste materials, which causes lot of environmental hazards and ecological imbalance. India imports a large amount of nickel and ferro-nickel to meet its growing demands in various sectors. For import substitutions, efforts have been made to produced ferro-nickel from the lean deposits of nickel bearing lateritic ores/ chromite over burden materials by reduction roasting followed by magnetic separation and then the nickel rich magnetic fraction is smelted to produce ferro-nickel. It has been possible to produce ferro-nickel of grade varying from 4-25% nickel.IntroductionDuring mining of chromite ore, large quantities of overburden materials are being generated. The materials amount to approximately 10 million tones per year contain around 0.3-0.9% Ni, 0.02-0.06% Co, 20-50% Fe and 4-9% Cr2O3 depending upon the location and the depth of the mine. These materials presently do not find any application for the extraction of nickel due to lack of a suitable technology. The materials are also unsuitable for ferro-nickel making because of their very high iron to nickel ratio. The country is seriously looking for a suitable technology to utilize these resources as its entire domestic requirements of nickel is met though imports. In this connection, a systematic approach has been made at the Institute of Minerals and Materials Technology, Bhubaneswar to develop a process for ferro-nickel making from this indigenous resource."

Jan 1, 2011

By B. Wasmund, K. Adham, K. O'Keefe, C. Lee

"Metal chlorides (e.g. iron and nickel) can be pyrohydrolysed at elevated temperatures to yield an HCl rich off-gas and a metal oxide product. Typically, the high energy requirement for pyrohydrolysis is provided by the combustion of a hydrocarbon fuel with air. Here, it is demonstrated that the use of oxygen-enriched combustion can result in lower fuel requirements and higher HCl concentrations. In addition, the oxygen enrichment can result in a smaller volume of off-gas and thus, smaller and less expensive process equipment. This new concept can be applied to both the spray roaster (SR) and the fluidized bed reactor (FBR). Similar to the aircombustion case, the oxygen-enriched process can use a direct contact venturi scrubber, to recover energy from the roaster off gas, but at a higher efficiency. The new process also uses an absorption tower for capturing HCl from the roaster off-gas, but generates a stronger HCl solution than is possible with pyrohydrolysis in air.BackgroundIn recent years, the metallurgical industry has become increasingly involved with developing methods for extracting metals, upgrading products or cleaning metallic products by using hydrochloric acid. These applications of chloride metallurgy often result in metal chloride solutions, which should be processed to regenerate HCl for reuse, and to recover the metal value as a product or by-product oxide [2, 3, 4].The pyrohydrolysis of metal chloride solutions has been done in two types of air roasters: spray and fluidized bed. The existing roasters burn a hydrocarbon fuel in air, to provide the required energy for evaporating the feed solution and to provide an elevated temperature for the chloride pyrohydrolysis to occur, according to the following reactions:"

Jan 1, 2011

By V. M. Paretsky

The basic work conducted by Prof. A.Yazawa has demonstrated that in order to ensure single- stage white metal production by autogenous smelting of copper sulfide raw materials, it is most favorable to use highly basic slags, in particular oxide systems CaO-FeO-Fe2O3-SiO2. The special studies have been conducted in the Gintsvetrnet Institute to investigate the composition and structure of slags produced on a semi-commercial scale when testing the KFP and FBP processes for white metal smelting. as well as the slag obtained in a full-scale KFP furnace at the Almalyk copper smelter. The investigations conducted have demonstrated why production of high-grade matte or white metal is associated with lower loss of copper in slag in a series: silicate slag I silicate-calcium slag I ferrite-calcium slag.

Jan 1, 2003

By Konstantina Chalastara

Mixed phase titanium dioxide (TiO2) nanoparticles synthesized through hydrolysis of TiCl4 solution at different conditions, namely concentration, pH, and residence time are characterized and evaluated as photocatalysts. The process is operated in a continuous stirred-tank reactor, CSTR giving blends of anatase, brookite, and rutile nanoparticles that were further evaluated to find the optimum mixture for a photocatalytic sorption material. The titania nanoparticles are first characterized in terms of photocatalytic activity under UV light illumination using an organic model compound (methyl orange) and after that are tested for removal of toxic selenate and selenite species from simulated effluent waters.

By Shuqiang Guo, Dingsheng Tan, Weizhong Ding, Zunyu Hu

"The mixture of hydrochloric acid and magnesium chloride is a good lixiviant for leaching of laterite. The solution can enhance the leaching ability because of the proton activity deviated positively from ideal. Otherwise, the existence of magnesium chloride in the lixiviant affects the dissolution behavior of magnesia, which may be an advantage of the process with less hydrochloric acid consumption. An investigation of magnesia particle dissolved in strong hydrochloric acid solution has been conducted. Influences of concentration of the magnesium chloride and hydrochloric acid and temperature on magnesia dissolution were studied. The dissolution mechanism was also discussed in this paper.IntroductionThere has recently been much interest in the use of hydrochloric acid leaching processes for recovering metal from ores or secondary resources [l-41_ Compared with sulfuric acid, the use of hydrochloric acid as lixiviant offers significant advantages including faster leaching kinetics even at atmospheric conditions, higher leaching rate and greater solubility for most metal chlorides [5-61 .With the gradual decline of the nickel sulfide supply, the extraction of nickel from laterites has become increasingly attractive [7-s1. Nickel may be co=ercially recovered from laterites both by pyrometallurgical and hydrometallurgical processes. The drawbacks of pyrometallurgical processes include the requirement of high grade ores, substantial energy input and loss of cobalt bound within ores. The extraction of Ni from lower grade nickel laterites ores is suited by hydrometallurgical routes, which play an increasingly important role with depletion of higher grade deposits."

Jan 1, 2014

By K. Ohmori, K. Takeya, S. Yoshizawa, A. Kawamoto, T. Ishikawa

"High performance Sm2Fe17N3 magnet powder is developed nitriding Sm2Fe17 alloy that 'is made using a reduction and diffusion method. Typical remanence, coercivity and maximum energy product of the fine powder are 1.40 T, 1.13 T and 323 kJ/m3, respectively. Decreasing samarium content, oxygen content and the amount of a-Fe are found to be the important factors to realize high-energy product.High performance injection molded Sm2Fe17N3 anisotropic magnet is also developed using the powder and an original binder system developed in order to mold at low temperature. Typical remanence, coercivity and maximum energy product obtained are 0.77 T, 0.78 T and 103 kJ/m3, respectively in the density of 4.77 Mg/m3The temperature coefficient of remanence is -0.07 %/K and that of coercivity is -0.54.%/K. The initial irreversible flux loss of the magnet that has a permeance of two is -5 % at 100 °C and the irreversible .flux loss of it is -4.4 % exposing it at 80 °C for 1000h.IntroductionSm2Fe17N3 alloy powder is expected to be very useful for a bonded magnet. The reasons are as follows. The magnetization is as large as the Nd2Fe14B alloy. Curie temperature is even higher than the alloy. The uni-axial anisotropy is comparatively higher than the alloy. Consequently it is possible to obtain high coercivity after just milling the powder and therefore possible to obtain high-energy product in a bonded magnet as it is realized in the SmCo5 bonded magnet. On the other hand, sintering is difficult because it will be decomposed into samarium nitride and a-Fe when heating it up to 500°C:"

Jan 1, 2000

By J. -S. Park, H. -S. Jeon

This study has been carried out to develop a relatively simple hydrometallurgical process for recovering nickel as nickel sulfate from the spent nickel-cadmium battery residue in which cadmium was removed by vacuum distillation. This residue is composed of 36 % nickel, 20 % iron, and other metals such as cobalt. First, crushing and selective classification were performed to separate iron to produce a nickel-rich product (over 40 % nickel). This product was dissolved in sulfuric acid to obtain a nickel sulfate solution. During the dissolution, nitric acid and air were added to the system to enhance the iron oxidation reaction rate. The free acid remaining in the dissolved solution was neutralized by adding nickel carbonate. Iron was precipitated as iron hydroxide and removed from the solution. The nickel sulfate solution was then fed to a vacuum evaporator to concentrate the solution by evaporation of water and crystallized at around 45°C to obtain nickel sulfate hexahydrate. A recrystallization process could remove other impurities such as zinc and manganese.

Jan 1, 2000

By P. J. Uggowitzer, H. Kaufmann

"New Rheocasting is a novel route of semi-solid casting, in which the globular semi-solid precursor material is produced by controlled cooling of only slightly superheated melts in conventional steel crucibles. The resulting semi-solid slugs are placed into the sleeve of a vertical Squeeze Casting Machine and then filled into steel dies. Solidification occurs under hydraulic pressures up to 100 MPa Due to the reduced cost of precursor material, reduced investment cost and easier recycling, the New Rheocasting process offers cost reductions of up to 25% over conventional semi-solid casting · routes. The New Rheocast products are pore free, pressure tight, weldable and heat treatable castings.In the present work the New Rheocasting Process is introduced and the influence of heat treatment on mechanical properties of the New Rheocast alloy A356 is discussed.The alloy A356 is cast under ideal New Rheocasting conditions into a step die on an UBE HVSC 350 Squeeze Casting machine. As-east, TS and T6 heat treatment conditions with variations in solutionizing and aging time/temperature parameters are applied and the samples are tested by tensile testing. Alternatively, the same heat treatment conditions are applied to conventional Squeeze Casting parts and compared with New Rheocasting.Questions of potential cost savings due to modified heat treatment conditions are also addressed in this paper."

Jan 1, 2000

By Esther Carrera Martinez

Caraiba Metals is the sole brazilian copper custom smelter. The sulfur present in the various concentrates processed is recovered as sulfuric acid and oleum ,which are sold in the local market For quality assurance purposes, a study was carried out in order to determine how to control the arsenic content in the acid, allowing the continuous processing of concentrates with high levels impurity, The study was based on the process parameters of the washing towers and mist precipitators, Others process variables were investigated and their effects were used in support to confirm the results, After many analyses performed some interventions to improve the quality of the acid were implemented in the plant, which proved to be successful even by using a conventional purification system,

Jan 1, 1996

By XUEWEN WANG, Bowen Li, Mingyu Wang

A novel technology characterized by higher extraction of vanadium and recovery of valuable elements was developed to recover vanadium from stone coal. The brief flow of the novel technology mainly includes low temperature sulphation roasting, water leaching, recovering potassium, aluminum, copper and selenium, solvent extraction enrichment vanadium, precipitation of red vanadium, removal sodium from red vanadium and calcinations. The total recovery of vanadium reached 76.3%, which was higher than the current applied technology. The novel technology was environmentally-friendly and could extract vanadium from the stone coal, in which the content of V2O5 was less than 0.8%.

Jan 1, 2015

By Rubén Alvarado

The markets and environmental protection rules are more and more exacting, both of which have determined that copper smelters should look for technological development and global management to ensure their viability and competitivity in the short and long term. The main facilities of the present and future Smelting-Converting Process at Codelco's Caletones Smelter, is based on Teniente Converter reactors with a high operational availability that have reached concentrate processing capacities near 2,000 tpd. These reactors are in operation in most of the smelters in Chile as well as in Zambia, Peru, Mexico and, in ?the near future, in Thailand. Since 1993, the Smelting-Converting process of the Caletones Smelter of Codelco-Chile has been based on one Reverberatory furnace, two Teniente Converters and four Peirce-Smith Converters. These facilities, together with the operation of two Fluidized Bed Dryers, three Slag Cleaning Furnaces, and two Oxygen Plants have allowed the smelter to reach concentrate smelting capacities and copper productions of 1,215 kt/year and 360 kt/year, respectively. This transitional operating scheme, combining together traditional and advanced technological equipment, needs further modernization to successfully face the modern world challenges, especially with relation to the environmental commitment, production costs and wide satisfaction of customers. For this reason, for the period 1997-2000, a Modernization Plan has been worked out. This plan considers an increase of the present throughput, which will permit a significant increase in productivity, as well as finding a definitive solution for meeting the environmental regulations. Among these projects, we can point out the definitive shut down of the Reverberatory Furnace, which is a contaminating piece of equipment of low energetic efficiency. Additionally, it considers the installation of two new Slag Cleaning Furnaces, one additional Oxygen Plant, and the incorporation of two new Sulphuric Acid Plants with a production capacity of 4,500 T/D, that will recover over 92% of the sulphur content, of process off-gases.

Jan 1, 1998

By Tobias Dubberstein, Hans-Peter Heller

The viscosity of Fe-Cr-Mn-Ni TRIP/TWIP (Transformation Induced Plasticity, Twinning Induced Plasticity) steel with varied nickel content is investigated using a vibrating finger viscometer. The viscosity of the melt is calculated from the change in power input in the field coil by an immersed finger into the liquid steel to maintain a constant peak-to-peak amplitude of the sine wave of oscillator compared to the idle state. Nickel content in steel is varied from 3 wt% to 9 wt%. The dynamic viscosity (η) at 1600 °C for 3 wt% Ni is 3.73±0.14 mPas, for 6 wt% Ni 3.50±0.03 mPas, and for 9 wt% Ni 3.93±0.09 mPas. There is a kink from low to high nickel content in viscosity values of Fe-Cr-Mn-Ni alloys. This phenomenon can be explained by a change in coordination number in the melt, as reported for Fe-Ni binary system in literature. The availability of viscosity data delivers relevant input to model free fall atomization processes of FeCrMnNi alloys.

Jan 1, 2015

By Mingchun Lu, Zhe Wang, Mingming Cao, Xiangdong Xing, Shan Ren, Jianliang Zhang, Zhengjian Liu

"The effect of reduction temperature on the vanadium titano-magnetite carbon composite pellets was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the discussion has put emphasis upon the enhanced reduction mechanism of additives containing CaF2 and NaF in this paper. The results showed that the reduction temperature of 1350°C was needed for the generation, mergence and growing up of metallic iron as well as monomer dissociation between metallic iron particles and slag phase in the vanadium titano-magnetite metallization pellets. The iron compound was completely reduced into metal iron, and Fe2Ti04 was mainly transformed into metal iron, (Fe,Mg)Ti205 and FeTi03 at 1350°C. The maximum metallization ratio was only 88.5% at 13500 for 30 min without any additive. However, with the addition of 3.0% CaF2 or NaF, the metallization degree of pellets could reach up to 94.8% and 92.5%, respectively.IntroductionVanadium titano-magnetite which is mainly distributed in the area of Panxi, Chengde and Maanshan in China is a kind of complex iron ore which contains various valuable metal elements such as iron, vanadium, titanium, etc. Among the above areas, Panzhihua (Sichuan Province in China) area possesses the largest deposits of vanadium titano-magnetite and the future reserves are more than 100x108t, and the reserves of Ti existing as Ti02 reach to 8.7x108t which occupy over 91% of the whole nation and ranked No.1 in the world[1]. Lots of researches on the comprehensive utilization of vanadium titano-magnetite have been conducted in the world. And many technological processes have been applied successfully in industrial production. Among these processes, the process of rotary kiln-electric furnace is employed to recover iron and vanadium in South-Africa, while the process of blast furnace-rotary furnace is widely used in Russia and China. Besides, many researchers have made efforts on employing new direct reduction process to realize the effective comprehensive utilization of vanadium titano-magnetite[2-4]. However, the direct reduction process is only researched in laboratory and it has not been used in industry."

Jan 1, 2013

By V. J. Ramirez, A. M. E. Noguez, M. J. Navarrete, B. G. Salas, N. T. Robert

"The close die forging stress in truncated conical cavities is evaluated with dimensional analysis. Five dimensionless groups are proposed from the process variables in order to simplify the forging stress determination. These groups are experimentally related and graphically expressed. This methodology can be used to predict the actual forging stress in industrial close die forgingThe use of the dimensionless groups allow to comprise more cases than the presented here, provided similar geometries and operational conditions.Introduction.Closed die forging is essentially a plastic deformation inside a two piece mold (forging die) with the inverted shape of the actual forging geometry. This plastic deformation will always be the result of a compressive stress. There are theoretical models which include complex calculations for the analytical determination of stresses (1, 2, 3, 4). Results of these calculations are approximate, requiring generally ulterior tests to obtain the true operational conditions(5).In this paper, it is presented a simplified approach to the actual compression stress needed in the forging. A well known tool in engineering: the Buckingham's Pi theorem in conjunction with dimensionless groups and a working piece scale model is used. Dimensional analysis will give the dimensionless terms needed to experiment with a selected scale model geometry to make the stress determination. The results presented demonstrate the reliability of this methodology."

Jan 1, 1997

By Knut H. Bech, Stein Tore Johansen

"The collision efficiency for small particles relative to 2D spherical bubbles in a developed turbulent flow field were calculated applying an adopted version of the CPD program FLUENT. The turbulence field was related to bubble size and fluid properties. The results were compared with analytical theory. The turbulence intensity was found to be the most important single parameter for collision efficiency. Effects of boundary layer thickness and particle diameter were discussed. IntroductionRemoval of inclusion particles from melted aluminium can be facilitated by means of a rotor system that supplies kinetic energy and gas bubbles to the floating metal. At the surface the inclusions adhere to the surface dross or slagg which is removed at regular intervals by the operators. When applying computational fluid dynamics (CFD) to model such a system, one experiences difficulties with the large range of turbulent length-scales encountered, from the large geometrical scales of the rotor and container, through the bubble size and down to the particle diameter. A mathematical model for the complete system will be both complex and require an extreme spatial resolution. Another way of dealing with the problem is to model the micro-scale phenomena separately and apply the results to create a model for the macroscopic system. In a previous work [12] we addressed these problems and developed a procedure for calculating turbulence enhanced flotation to bubbles. It was found that turbulence may have a profound effect on the collision rate of particles to idealized bubbles. In this study we recognize that only a fraction of the total turbulent kinetic energy generated by the rotor's work on the liquid metal may contribute to enhanced flotation. By using a model spectrum for the turbulence, the fraction of turbulent energy in eddies smaller than the bubble diameter is calculated. A twodimensional CFD model was then constructed to calculate the collision efficiency between particles and bubbles of various sizes."

Jan 1, 1999

By Nobuo Kikumoto

Recently, the treatment of industrial waste materials has been a serious social problem here in Japan. Filling them in ponds is now strictly prohibited due to a limited land area and incineration method is also regulated as not to generate DXN. In these conditions, Onahama Smelter has begun to treat shredder dusts (SD) of car at reverberatory furnaces to recover various metals such as copper, gold, silver and palladium without generation of DXN. The total volume of these dusts is expected more than 1 million metric tonnes a year in Japan. Onahama Smelter is now planning to treat about 20% of them in the near future by using tonnage oxygen. In this paper, the heat balance, control method of DXN and treatment of these dusts in reverberatory furnaces are described. DXN : Dioxin (The generic term of PCDD and PCDF)

Jan 1, 2000