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By Tianjiao Luo

The electroless copper plating process for continuous carbon fiber using CuSO4?5H2O as the main salt and formaldehyde as reducing agent was experimentally studied, including the effects of pH values and concentration of chelating agents, stabilizing agents and reducing agent on the electroless plating process. The surface morphology and the composition of coating were investigated by means of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), and deposited the coating thickness was measured by way of dissolution. The results indicated that the pretreatment of carbon fiber before plating was so important. This pretreatment could prevent the formation of the black cores, furthermore, it could form many active absorption cores with Ag as the center on the carbon fiber surface. Used the optimized parameters in this process, which led to a stable solution for plating, a homogeneous copper coating was conducted with the carbon fiber plated with favorable mechanical performance and high adhesion strength.

Jan 1, 2006

By Elli Miettinen

In Copper Flash Smelting operation disturbances may lead into dust build-up in the gas train and off-gas handling system causing reduced heat recovery efficiency and process availability. Flue dust of a Copper Flash Smelting process heat recovery boiler has been characterized and its thermal conductivity and diffusivity have been determined. Dust accretions consist of several layers possessing varying particle sizes, densities, and thermal properties, with the binding phase usually being sulphate. All the dusts can be regarded as effective thermal insulators with thermal conductivity values of less than 2 W/mK and thermal diffusivity values of less than 0.005 cm2/s. Porosity can be regarded as a fairly good indicator of the thermal transport efficiency of these types of materials, but the material microstructure must also be considered. The results can be used in the dimensioning of metallurgical heat recovery boilers and they also provide accurate input data for process models.

Jan 1, 2009

By Rajesh Kumar Mishra

About 500,000 troy ounces of Platinum Group Metals (PGM) will be available for recycling each year from spent automobile catalytic converters in North America alone. Platinum Group Metals? from spent catalyst can be extracted by Hydrometallurgical, Pyrometallurgical or Gas Phase volatilization processes. This paper is a review and comparative study of various processes investigated for PGM extraction. A number of processes described in this paper have already been commercialized. The technical and environmental aspects of the important processes are discussed.

Jan 1, 1989

By Roberto Parreiras Tavares, Frederico da Costa Fernandes, Guilherme Antonio Defendi, Vangleik Ferreira da Cruz, Júlio César de Sousa Pena

"Near-net-shape casting is an important area of research in the iron and steel industry today. Among the near-net-shape casting processes, the single-belt caster seems to be the most promising, since it is the only one that can achieve levels of productivity similar to those obtained with conventional continuous casting machines. One of the most important aspects in the single-belt casting is the feeding system used to deliver liquid metal over the belt. This system determines the velocity distribution and the levels of turbulence of the liquid metal and affects the quality of the strips. In the present work, a metal delivery system having a simple geometry was proposed. Using the CFD code CFX 5.6, a mathematical model to simulate three-dimensional turbulent fluid flow and heat transfer in that system has been developed. This model was used to analyze different configurations of the metal delivery system and the free surface shape of the fluid was also determined. A physical model of the feeding system was built and used to validate the predictions of the mathematical model. The fluid flow calculations have been validated by dye injection experiments and laser doppler anemometry. Measurements of the free surface levels have also been performed. These experiments provided supporting evidence for the predictions of the mathematical model.IntroductionTo maintain its competitiveness in the present market, the metallurgical sector, particularly the steelmaking companies, are developing new techniques of production. Some of these new processes are focussed on the strip casting technologies. Among these technologies, the SingleBelt process is considered the most interesting option, reducing the number of rolling steps and, consequently, the final cost of the product, especially the part associated to the energy consumption (fuel and/or electric energy). This process can also reach levels of productivity that can not be matched by other strip casting methods(1). One of the most important aspects concerning these new processes is related to the liquid metal delivery system. This system can have a significant effect on the final quality of the strips, since it determines the velocity distribution and the levels of turbulence of the liquid metal."

Jan 1, 2004

By Jörg Wallner

In order to limit SO2 emissions, the Montanwerke Brixlegg AG has installed a desulphurisation plant with the primary aim of reducing the peak emissions from the copper converter that are of particular ecological concern. The author discusses the process requirements, the desulphurisation process selected and the results achieved.

Jan 1, 1996

By David B. George

Kennecott Utah Copper adopted Outokumpu Flash Smelting and Kennecott-Outokumpu Flash Converting in 1995, a process based on granulating high grade copper matte. While nickel mattes and very small quantities of copper matte had been commercially granulated for years, no large scale copper matte granulation system had been built. This paper summarizes the history and benefits of copper matte granulation, the Kennecott design basis, the successful operation for over 10 years and potential problems inherent in some matte granulation approaches.

Jan 1, 2006

By I. Goy D. Gaballah

Decontamination of synthetic K2Cr2O 7 solutions containing 10 to 1000 ppm of hexavalent chromium using chemically treated barks have been studied at a laboratory scale. Metal removal from solutions depends on the pH, the initial concentration and the bark species. The use of a pulp density of 2 % in an agitated flask at the optimum pH for 2 hours leads to a percentage chromium removal of about 95 of the initial metallic ions content. Other trials conducted by column percolation permit the determination of the maximum retention capacity of the treated bark. Depending on the bark species, oak or pine, the rate of saturation is 110 and 215 mg of Cr per gram of bark respectively. The incineration of the metal charged barks gives recyclable, ashes containing 36 and 54 % of chromium metal for the oak and pine barks respectively. Experiments, of Cr6+ removal from industrial effluents containing up to 1800 ppm have been carried out on the semi-pilot plant scale. They have lead to the elimination of about 90 % of hexavalent chromium from this industrial waste solution. Further studies are conducted in order to define the hexavalent chromium binding mechanisms on bark constituents.

Jan 1, 1992

By Zhao-feng Xie

A new process of recycling valuable metals containing in the slag of jamesonite smelting in the blast furnace was studied. In this process, the valuable metals such as Pb, Sb, Zn and In etc. were fumed and volatilized and enriched in the dust firstly and then the dust was leached by sulfuric acid. In the leaching procedure, Zn and In in the dust entered into the leaching solution and were separated from Pb and Sb which remained in the residue.The optimal operation conditions of the fuming procedure are as follows: the mass ratio of the blast furnace slag, coal powder and lime are 100:22:10 respectively and the fuming time are 1.5~2.5 h, the fuming temperature is not below 1200C and the volatilization rates of Pb, Sb, Zn and In are 95%, 92%, 86% and 75% respectively. The optimal conditions for the leaching procedure are also presented: the consumption of sulfuric acid is 1.15 times of the theoretical consumption, the ratio of liquid to solid is 4:1 and the leaching temperature, leaching -1time and stirring speed are 90, 1.5h and 300 r?min separately. The leaching rates of Zn and In are 98.5% and 95.2% respectively. The experimental results shows that the valuable metals in the dust can be recovered and separated effectively by this process and the?ir recovery efficiencies are as follows: Pb94%,Sb91%, Zn84% and In69%.

Jan 1, 2009

By K. Adham

"Fluidized beds are utilized in a wide range of high-temperature applications throughout the metals and materials industry. Their main advantage is the fast and uniform heat and mass transfer between the hot combustion gases and the particulate solid feed. A further benefit can be the lowering of the processing plant's energy consumption, through heat recovery from the fluid bed processes used for solids heating. Here, the enhanced energy efficiency of fluidized systems is investigated and the modeling results are discussed for three configurations: the flash tube, the single bubbling bed and the multi-stage fluid bed. Key thermal design aspects of each system are identified based on results from process simulations, in order to benchmark their main operating features and overall energy efficiency. Suitability and applicability of each configuration is also discussed based on a number of process and material property considerations.IntroductionCombustion based heating of particulate solids is commonly done using three different types of fluidized beds. The flash tube (FT) is similar to a hot pneumatic transport system. The single-stage fluidized bed (FB) typically uses in-bed combustion. The multi-stage fluidized bed (MSFB) can have two or more stages stacked into a tower.Flash tube (FT) suspends the incoming solid charge in a high-velocity stream of hot combustion gases. To maintain the solids suspension in the FT, two parameters are required: high velocity for elutriation of the particles and adequate solid-to-gas ratio for avoiding high pressure drops and solids drop-out [l].The fluid bed (FB) works at much lower velocities than the flash tube. Therefore, most of the solids are not conveyed in the gas stream, but are only suspended in a liquid-like manner. At minimum fluidization velocity (Umr), the gas flow exerts just enough force on the solids to keep them suspended in place [2].Multi-stage fluid bed (MSFB) heats up the solids as they are transferred from an upper bed level to a lower one, counter-current to the rising flow of hot gases generated at the lowest stage. As the temperature and volumetric flow of the gases decrease from bottom to the top stage, smaller bed diameters can be used in the energy recovery stages [3]."

Jan 1, 2014

By Hongyang Cao

The iron constituents selectively separated from the modified copper slags by magnetic separation and flotation.were studied. The results of magnetic separation for modified copper smelting slags show that the grinding size, current intensity and dispersant agent had great influence on grade, and recovery ratio of TFe in preparation concentrate; The results of flotation for magnetic concentrate show that the positive flotation of sodium oleate negatively upgrade the grade of magnetic concentrate, but the reverse flotation of lauryl amine and soluble starch are effective. The grade of TFe can reach 54% and the recovery ratio can reach about 90% in magnetic concentrate, when the grinding size is 45.8µm and the current intensity is 2.5A. The optimal effect is obtained by using lauryl amine as collector and soluble starch as depressant to reverse flotate magnetic concentrate, and the grade of TFe is upgraded 2.37%.

Jan 1, 2009

By Yunnen Chen

This work concerns the removal of zinc(II) and COD by means of sawdust obtained as a by-product from locally used wood. The zinc(II) and COD removal study has been carried out batchwise where the influence of physico-chemical key parameters such as tree species, pH value of solution, temperature and contacting time and dosage of adsorbent have been considered. The maximum percent removal was attained at pH 9 all for Zn(II) and COD after about 60 min. The adsorbent can be effectively desorption using 0.1 M HCl. The experimental results showed that ion exchange maybe the major adsorption mechanisms for binding the divalent metal ions to the sawdust. Sawdust was a potential adsorbent for the removal of Zn(II) from the effluent of electroplating industry.

Jan 1, 2009

By Fiseha Tesfaye, Pekka Taskinen

"Thermodynamics of the equilibrium phase assemblage Ago_9Cul.lS-Cu2-xS-CuS have been studied by an EMF -method. The ternary phase was synthesized from the pure Cu2S and Ag2S in vacuum furnace at high-temperature and mixed with appropriate compositions of Cu2S and CuS to form the cathode electrode. The EMF-measurements were made on the solid-state galvanic cell Pt(-) I Ag I RbAg,ils I Ago9Cu1.1S-Cu2-xS-CuS I Pt(+), in a temperature range from 316 K to 498K.Based on the measured EMF vs. T relations, thermodynamic functions (?fG° , ?fS and ?fH°) of stromeyerite (Ag0.9Cu1.1S) in equilibrium with Cu2-xS and CuS have been determined. The obtained experimental values have been compared with the available literature values. New experimentally determined thermodynamic properties of the solid solution (Ag,Cu)2Sss were determined.IntroductionDue to intense mining of high grade sulfide ore minerals in the past, recently, the available sulfide ores are poor in metals and becoming increasingly complex; such that, the production of high grade metals by the conventional pyrometallurgical processes is compromised. Consequently, smelters are in need to modify their operating flow sheets and strategies for processing more complex feed materials economically, while meeting the strict environmental regulations. To make the appropriate modifications, accurate thermochemical data of phases and phase assemblages which exist in these complex ore minerals are essential.Silver-bearing sulfosalts are encountered in ore minerals for the production of base metals and are common sources of silver. Among the silver-based sulfosalts, stromeyerite (Ag0_9Cu1.1S) is relatively common ore mineral in most hydrothermal vein and replacement deposits [1]. Recently, the ternary chalcogenide compound Ago0.93Cu1,07S has been studied, intensively, due to its high ionic conductivity and gradual disorder in the sequential phase transitions [2]. Therefore, accurate knowledge of the thermodynamic properties of stromeyerite has considerable fundamental and practical interest in many aspects of extractive, chemical and physical metallurgy."

Jan 1, 2014

By J. S. Kirkaldy

A theoretical procedure is demonstrated for calculating two-dimensional binary cellular single-valued interfaces and extended to triple-valued (remelt) shapes. The numerical calculations for the single-valued local equilibrium problem which yield unique shapes as functions of the supersaturation parameter a and the partition coefficient k are reviewed. The cell amplitude L and wavelength A scale identically as the inverse velocity to the 112 power and the aspect ratio r is a constant equal to 312, independently of a and k for a < 0.5.. For 0.5 < a < m, L, A and r decrease asymptotically to zero indicating the finite amplitude nature of the instability at a = 1 and the existence of sub-marginal states which converge to a flat interface at a- m (Glv- m). Scaling comparisons between equilibrium single-valued and triple-valued and deep-rooted non- equilibrium cells are made.

Jan 1, 1992

By Roderick I. L. Guthrie, Donghui Li, Mihaiela Isac, Luis Calzado

The HSBC is an ideal process for the production of BMG strips. The purpose of the present work was to investigate the casting of Ca-based, bulk amorphous strips. The possibility of casting three Ca-based alloys (60Ca-20Mg-20Al, 60Ca-15Mg-10Al-15Zn and 55Ca-15Mg-10Al-15Zn- 5Cu (at.%).) was investigated, using the HSBC simulator. Numerical simulation and mathematical modeling were used to predict temperature variations and cooling rates, under different interfacial gaseous atmospheres (helium and air) near the meniscus region. Given the critical cooling rates and glass temperatures needed to be reached for the vitrification of the respective alloys, this leads to predictions of the critical thicknesses possible with this novel casting process. To validate our predictions, these alloys were then prepared and cast onto the sand-blasted, solid copper substrate mould of the HSBC simulator. The possibility of producing Ca-based metallic glassy strips via the HSBC processes was confirmed, using optical microscopy, X-ray diffraction and Scanning Electron Microscopy, to characterize the glassy properties of the cast strips. It was found that the HSBC process would be able to provide sufficient cooling to form amorphous strips for the 60CA-15Mg-10Al-15Zn and 55Ca-15Mg- 10Al-15Zn-5Cu alloys, but not the 60Ca-20Mg-20Al alloy.

Jan 1, 2014

By David Bequette, Ray D. Peterson, Cynthia K. Belt

"With a need to cut production costs in the metals industry, cost savings from energy efficiency improvements are critical. Opportunities can be found by reviewing furnace systems and practices so that the melting and holding processes operate at the highest energy efficiency. Many of the changes can be implemented with a minimum of expense or capital investment. This paper will review several low cost methods to optimize energy efficiency on reverberatory melting or holding furnaces. These five methods (furnace utilization, idle procedures, fire rate, controls, furnace pressure) will be explained and information given to implement these changes. Included are several rules-of-thumb and benchmarks for aluminum reverb furnaces.IntroductionEnergy can be a significant portion of the total manufacturing costs for metals and materials manufacturing involving thermal processing such as heat treating, melting, and high temperature processing. Natural gas prices have dramatically varied over the last few years. While no one can foresee the future, prices are expected to increase from the current low prices. More recently, emphasis is being put on the reduction of greenhouse gases with the potential of additional costs to industry.One of the first steps in an energy management program is to measure the energy usage of the process [1]. The results are typically understood in relation to the mass melted in kWh / mT [BTU / lb]. For the purposes of this paper, furnace energy efficiency is calculated over a month or even a year and thus includes hold times. This efficiency is typically different from the values quoted by furnace manufacturers. Those values are for limited short term tests at highutilization.Once you know the performance for your furnaces, these should be compared to industry benchmarks. For aluminum melt furnaces with cold air burner systems, a benchmark value or goal is 1800-2000 BTU/lb [1160-1290 kWh/mt], though some of the best have reached 1600 BTU/lb [1030 kWh/mt]. Furnaces with regenerative burners can attain 1100-1200 BTU/lb [710- 775 kWh/mt]. There are some designs of multi-chamber furnaces or oxygen furnaces that have improved on these numbers, perhaps as low as 950 BTU/lb [615 kWh/mt]. Typically, as the degree of sophistication and energy efficiency of the furnace increases, so does the cost."

Jan 1, 2010

By Ole Rud Bendixen

Topsoe has developed a Wet gas Sulphuric Acid (WSA) process which effectively recovers SO2 in off-gases from non-ferrous smelters and roosters. The product is concentrated sulphuric acid of typically more than 96 wt% irrespective of SO, concentration in off-gas. The process does not generate any waste products or waste water and does not use any absorbents or other chemicals. In the process, up to 99.3% of the SO2 is converted catalytically into SO3, which reacts with water in the gas, hereby forming gaseous sulphuric acid. The acid is condensed in a WSA condenser of proprietary design. Excellent heat economy and practically no sensitivity to the water balance mean that no extra sulphur burning is required at any S02 concentration, The process is especially well suited for treating off-gases where the SO2 content is lower than approx. 5-6%, and it is a good alternative to a complete renovation of a smelter. However, also off-gas from flash smelter may be treated. The process has found good use in both molybdenum and lead roosters. An example from a molybdenum roaster in Chile shows that 97-98wt% acid is produced from a 2.3 % S02 gas. This plant is situated in the outskirts of Santiago and represented a major local source of SO2. The plan was started in May 1993.

Jan 1, 1996

By A. Warczok

The oxidation and smelting of chalcopyrite, bomite, chalcozine and pyrite has been studied under simulated flash smelting conditions. The results of copper sulphide oxidation show that under constant oxidation conditions, the degree of oxidation drops sharply when the particle size is increased above a given range. This critical size range varies typically between 200 and 500 pm depending on the oxygen content in the gas phase. For bomite, chalcopyrite and pyrite, the critical size range increases with increasing iron content in the mineral and with increasing oxygen content in the gas phase. The extreme case is observed for pyrite in pure oxygen, where there is no effect of the particle size on the degree of oxidization. Microscopical observations of the oxidized products show the influence of different factors on the mechanism of oxidation and fragmentation of the sulphide particles. Based on microscopical analysis and phase identification of the oxidized products, a model has been proposed for the oxidation and smelting of copper sulphide particles in suspended state. The mathematical model describing the sulphide particle oxidation is supported by the obtained results. Using this model, it is possible to describe the role of particular factors in the sulphide minerals oxidation.

Jan 1, 1992

By Shuichiro Okada

Various efforts to reduce energy consumption and smelting cost are made at Tamano Smelter. Production of anode copper has been increased by about 30 % and energy requirement has been decreased about 50 % respectively. Challenges toward more higher goal are being continued. Details about the following are described in this paper. 1 Waste heat recovery Steam recovery at up-take of FSFE Heat recovery from waste gas of anode furnaces 2 Application of tonnage oxygen 3 Application of pulverized carbonaceous fuels to the flash smelting furnace with furnace electrodes ( FSFE ) 4 Application of computer control system to copper smelting 5 Improvement of the fugitive gas collecting system 6 Improvement of the mechanical tuyere puncher for the converter furnace

Jan 1, 1983

By Manuel Alvarado, David Nemir, Jan Beck

"Thermoelectric generation using special N-doped and P-doped semiconductors is well known as a means for direct heat energy to electrical energy conversion without the need for moving parts. The technology is used today in niche markets for low level electricity production and has been proposed as a scalable means for capturing large scale energy from waste heat streams. The choice of geometry of the thermoelements and conductors is critical to the successful implementation of a waste heat recovery system in order to manage losses due to Joule heating and diffusive heat flows. This paper describes a simulation study to define the performance impact of different aspect ratios for the active thermoelements and the electrical interconnect. The use of a finite element model that incorporates the intercoupled heat and electrical energy flows highlights some of the issues impacting scalability.IntroductionThermoelectric phenomena arise out of the intercoupled electrical and thermal currents in a material. A two-element thermoelectric generator is depicted in Figure 1. It is constructed by connecting an N-type thermoelement and a P-type thermoelement in electrical series, with both elements in thermal parallel between a heat source and a heat sink. The electrical series connection is made by attaching conductors as shown. Ideally, these series connection elements will be both good thermal conductors and good electrical conductors.The two element generator in Figure 1 is disposed between two thermal reservoirs: the heat source, which furnishes heat energy; and the heat sink, which absorbs heat energy. Heat energy flux Q, flows from the heat source to the heat sink, driven by the temperature difference between the source and the sink. As depicted in Figure 1, when a resistive load, R, is attached, electrical current, I, may be extracted from the thermoelectric generator and furnished to the load. The N-type and P-type thermoelements, are the active portions that do the actual conversion of heat energy to electrical energy. Although thermoelements may be built using conductors such as bismuth and antimony, higher efficiency thermoelectrics are built using heavily doped semiconductors. Thermoelectric devices are generally formed by connecting many pairs (couples) of N and P type thermoelements in electrical series and in thermal parallel. A commercially available module having 127 couples (254 elements) is shown in Figure 2."

Jan 1, 2011

By G. R. Palmer

The success of future electric vehicles will depend greatly upon the power supply choices made today. Research is presently being conducted by automotive engineers and electrochemists to determine what battery type may be the most promising. Not only are product production and application efficiencies being evaluated but also environmental concerns of reclamation and recycling. Rechargeable batteries using nickel-metal hydride electrodes are strong candidates for these electric vehicle applications. The U.S. Bureau of Mines is investigating hydrometallurgical technology that separates and recovers purified metallic components present in nickel-metal hydride battery scrap. Sulfuric, hydrochloric, and nitric acids are all capable of dissolving the battery electrode alloys given the proper operating conditions. Solvent extraction of the leach solutions using D2EHPA removes iron, and selective precipitation shows promise of recovering the other metals in the H2SO4 and HNO, systems.

Jan 1, 1994