Search Documents

By Leonid N. Shekhter, Corby G. Anderson, Esra Cankaya-Yalcin, Daniel G. Gribbin, Joseph D. Lessard, Larry F. McHugh

"A new process for smelting copper, Looping Sulfide Oxidation™ (LSO™) significantly and positively alters the smelting energy balance. This process uses copper oxide in conjunction with air for the desulfurization of copper and chalcopyrite concentrates. Copper oxide is regenerated in a flash type furnace and then ""looped"" back for the oxidation of the copper concentrate. Heat and material balances show that the Looping Sulfide Oxidation™ process requires significantly lower net energy than conventional technology. This process produces anode copper and higher S02 content off-gases for efficient formation of sulfuric acid. Additionally, the process yields slags with lower copper solubility as compared to the conventional technology.IntroductionBased on the positive results from LSO™ investigations [1], further lab investigations into co=on sulfides and metal oxides were performed. It was discovered that chalcopyrite (CuFeS2) is oxidized with copper (II) oxide. In this reaction over 98.5% of sulfur was removed as S02, while a significantly improved energy balance was observed. This paper intends to analyze both the conventional flash smelting process and the newly developed Looping Sulfide Oxidation™ process, comparing heat and material balance results. LSO™ yields improvements to the energy footprint for copper, opening the door to new copper processing opportunities."

Jan 1, 2013

The entrainment of copper matte in the slag during the slag skimming stage of a Peirce-Smith converter was studied with a dam break model. Experiments were carried out with a range of fluid pairs where the lighter fluid was allowed to overflow a weir and the amount of entrained heavier fluid measured. The resulting entrainment is measured as the ratio of the heavy to light fluid withdrawn. The fluids include oil-water, water- glycerol and salt solutions-water pairs to cover a wide range of densities and viscosities. It was found that the Richardson number, Ri, correlates the entrainment well. For the case of the liquid-liquid interface initially at the same height as the weir, the entrainment was found to vary with Ri-1/3. The transient flow was simulated with a volume of fluid (VOF) code written in-house and used a stairstep approach to represent flow obstacles. The code was validated against the experimental results with good agreement for the variation of the heights of the two fluid with time. The simulation showed that the prevailing mechanism for entrainment is due to a pressure differential created across the liquid in the converter during pouring resulting in the heavier liquid being rotated upwards and over the weir.

Jan 1, 1999

The reported values of the standard reduction potentials of the Au(NH3)2+/Au(0) and Au(S2O3)23-/Au(0) couples are reviewed to emphasise the experimental difficulties associated with the measurement of reliable values for these quantities. The standard reduction potential for Ag(I)/Ag(0) in ammonia and thiosulphate solutions measured at ionic strength 0.1 and 25oCis used to predict the following relevant stability constants () for gold complexes based on the linear free energy correlations: Au(NH3)2+2 = 1013, Au(S2O3)23-2 = 1024 and Au(NH3)43+4 = 1033. The equilibrium constant ( 10-11) for the reaction Au(S2O3)23- + 2NH3 = Au(NH3)2+ + 2S2O32- based on these stability constants is in reasonable agreement with the measured value (10-9) based on potentiometric and spectroscopic data when excess ammonia was added to a solution of Na3Au(S2O3)2. This also indicates that the stability constant of Au(NH3)2+ is 9 to11 orders of magnitude less than that of Au(S2O3)23-. Relevant species distribution and Eh-pH diagrams based on the revised data are presented.

Jan 1, 2003

By H. Kung, T. R. Jervis, M. Nastasi, T. E. Mitchell

"A systematic study of the structure-mechanical properties relationship is reported for nanolayered composites of MoSh-SiC, Mo-MoSh, Mo-MoShNx, MoSi2-MoSi2Nx, and Mo-MoShMoSi2Nx (x=3-4) synthesised by sputtering techniques. These composites have been studied by nano-indentation and cross-sectional TEM as a function of annealing temperature. As-deposited layers are amorphous except for Mo. With increasing annealing temperature, first MoSh and then SiC crystallize, while the hardness progressively increases until the layers start to spheroidize and grain growth sets in at 900ºC. For the case of Mo-MoSi2, the layers react and the composite deteriorates rapidly. However, MoSi2Nx remains amorphous up to 1000ºC, suggesting that it could act as a diffusion barrier between Mo and MoSi2. In fact the Mo. MoSi2Nx, MoSi2-MoSi2Nx and Mo-MoSi2-MoSi2Nx nanolayers are found to remain stable up to such temperatures. IntroductionMolybdenum dislicide, MoSh, is a potential matrix material for high temperature structural composites due to its high melting point and good oxidation resistance at elevated temperature [1]. The two major drawbacks for structural applications are inadequate high temperature strength and poor low temperature ductility. Silicon Carbide (SiC) being hard and thermally compatible with most ceramics and intermetallic compounds, has been found to be suitable for second phase reinforcement in various structural applications and, in particular, the addition of SiC whiskers improves the high temperature yield strength of MoSi2 [2]. While most of the research in MoSb-SiC composites has been on the particulate form of SiC, laminated composites may offer unique properties. It has been shown that synthetic multilayers with alternating layers of metal and/or compounds may exhibit interesting mechanical properties [3]. Enhancement in mechanical properties by decreasing the wavelength of multilayer spacing has been studied extensively. In general, two types of strengthening have been proposed: (1) Hall-Petch strengthening [4,5], where the strength increase is inversely proportional to the square root of the layer thickness; (2) Koehler modulus strengthening [6], which increases with modulus difference and decreasing layer thickness. In the present study, we have performed a systematic study of the relationship between strength and structure in a number of different nanolayered systems based on MoSh. Layer thicknesses have been varied and their nanostructures have been varied by heat treatment. Previous work on MoSi2-SiC is summarized [7]. In an attempt to improve fracture toughness, MoSh-Mo nanolayered materials have been prepared but are found to react and deteriorate. Previous work has shown that nitrided MoSi2 (MoSi2Nx with x=3-4) is highly stable [8] and so nanolayered composites of MoSi2-MoSi2Nx and Mo-MoSi2-MoSi2Nx have been prepared to assess the' stability and mechanical properties of these composites. Preliminary results are presented."

Jan 1, 1994

By Hiroshi Maeta, Takao Kino, Hirota Osono, Kikuo Matsusaka, Azusa Shida

"Prior to refine an ultra-high purity material, it is necessary to estimate the surface cleanness of a base material. In this report, the cleaning method of a surface for refining of an ultra-high purity aluminum has been studied. Aluminum sample of 99.999% purity was p9lished mechanically and electrically and washed with various solvents. Surface composition and a depth profile near the surface were examined. Based on the experimental results, surface structure of an ultra-high purity aluminum was discussed.IntroductionRecently, studies on high purity metals have become of interest, and we have reported .various properties of an ultra- high purity aluminum1- 2)In order to purify a metal, it is necessary to clean a work area and to make vacuous as possible. So, we are studying the purification of aluminum by an ultra-high vacuum refining system and a zone refining system set up in a clean room with cleanliness class of 1000.Now, in order to avoid a mixing of impurities into the refining metal, a surface cleanness of a base metal is very important factor. The purity of the base aluminum used our work is 99.999%, but the surface state of the base aluminum is not clear. Aims in this work .are to investigate the surface state and to obtain the cleaning method of the base aluminum.Experimental procedureSamples used in this work were 99.9% (3N), 99.99%(4N) and 99.999% (SN) aluminum produced industrially and 99.9999% (6N) aluminum purified by us."

Jan 1, 2000

By G. R. Adams, N. Y. Tang, N. Qiang

"Aluminum is the most important alloy addition to Zn baths for controlling the reaction kinetics between the steel substrate and molten Zn in continuous galvanizing operations. Due to the complexity of the Zn-Fe-Al ternary system, the measurement and control of effective bath Al remains a challenge for modem galvanizers. The successful development of Al sensors has made the real-time measurements of bath Al contents possible. To facilitate their application, a computer interface and a palm-size data logger have been developed by Cominco. Plant applications indicated that the sensor possessed sufficient accuracy for process monitoring and control. The working mechanism of the Al sensors and Cominco's development work is described, and the results of sensor applications are presented.IntroductionControl of bath Al content is critical in modem continuous galvanizing because it has a strong influence on coating structure and properties and the overall product quality. The control of effective bath Al content (Al in liquid solution) is particularly critical for galvannealing where a high bath Al content may lead to incomplete alloying during post annealing, and a low bath Al content may result in other operation problems, such as excessive bottom dross accumulation and difficulties in coating thickness control. The desirable accuracy of the Al control is within ±50 ppm of target levels. In principle, such an accuracy is achievable for modem chemical analysis facilities, such as atomic absorption photospectrometer (AAS) and induction-coupled plasma (ICP). However, a recent study carried out by the International Lead and Zinc Research Organization (ILZRO) indicated that such an accuracy is rarely achieved in the zinc and steel industries.(1)"

Jan 1, 1997

By A. V. Tarasov

A flow-sheet for waste-less processing of spent lead batteries comprises mechanized separation of batteries, smelting of the metallic fraction in a kettle, electrothermal smelting of oxysulfate fraction, refining of crude lead and processing of reverts to produce commercial products. Smelting of lead-containing fraction is performed in an electrothermal furnace using a processing technology developed in the Gintsvetmet Institute and differing from conventional processes by the fact that it does not require any fluxing agent (soda); no matte is formed in the process and the amount of slag produced is minimal, because its formation depends only on the ash content of coke and the quality of battery scrap separation. The process has been patented. It has been introduced on a commercial scale in 1.8 MVA furnaces at the plant of A0 "RyazTsvetmet" (Ryazan, Russia). The process has the following main advantages as compared with conventional shaft-furnace smelting and smelting in a short-drum furnace: the process does not require technical-grade oxygen, the amount of process gas generated is minimized ensuring a decrease in lead-containing dust and sulfur dioxide emissions by 3 to 5 times per unit of lead recovered; a decrease in dust entrainment resulting in lower amounts of recycled dust; lower slag yield (a decrease from 20-25% to 3-5%); lower coke requirement (a decrease from 10-14% to 3-4%). Refining of crude lead is performed using conventional technology but there are several unique features for which know-how is available. Processing of by-products of electrothermal smelting and secondary lead refining (slag, drosses, skimmings) and ebonite fraction (crushed battery casings) is performed in a slag-fuming furnace.

Jan 1, 2002

By Alex Meystel, Diran Apelian

"In this paper, an outline is given for a theory of intelligent control (IC) of manufacturing processes (MP) based upon what all of them have in common: all MP's can be represented as distributed networks of sequential/parallel elementary ""lumped"" models; all elementary models are organized by definite input-output conditions, and by the set of constraints; all elementary models incorporate not only well defined physical knowledge, but also assumed physical knowledge, expert knowledge, expected knowledge to be obtained during the process from sensors, etc. This creates a hierarchy of elementary controllers coordinated by local coordinators of different levels up to a global coordinator. The latter verifies the adequacy of MP by using a holistic image of the process: depictogram. The structure of knowledge based controller is introduced, and the analytical/linguistic tools of control are presented. The concept entails a number of perspectives which are discussed in the conclusions.1. IntroductionIt is becoming increasingly clear to those of us in Engineering and Technology oriented fields that the so called ""service industries"" do not create wealth. Moreover, it is now accepted that manufacturing is the key to the creation of wealth from a socio-economic point of view. This appreciation of the importance of manufacturing is reflected by the transformations we are seeing in our factories, as well as the changes in both curricula and research activities of our universities. Though we find these changes to be in the right direction, there is yet much more to be done to advance the frontiers of manufacturing and materials processing as we approach the third rnillenium."

Jan 1, 1988

By Nils Eivind Kamfjord, Halvard Tveit, Ingeborg Solheim

"Because of its negative environmental effect the attention towards NO emissions increases. This again leads to new demands from the authorities for better surveillance and control of emissions. Earlier and recent industrial measurements towards FeSi- and Si-metal furnaces reveal quite high NO-emission. The NO is believed to be produced in the combustion zone above the furnace surface, mainly as thermal NO.In order to expand the knowledge on NO-formation in silicon metal production, a pilot scale experiment in a 440 kVA silicon furnace has been carried out. The experimental set-up was designed with a view to be able to copy and manipulate the formation mechanisms for NO by controlling the flow of false air into the off-gas system.The resulting NO-values corresponding to the different air inlet to the furnace top, show significantly differences between the different air inlet geometries.IntroductionNOx is the common notion for the two gases nitric oxide (NO) and nitrogen dioxide (NO2). Since combustion of fuels, such as gasoline, diesel, bio diesel, propane, coal, and ethanol, forms NOx the dominating contributors to NOx emissions are the on-/offshore transportation industry and power generation based on fossil fuels [1]."

Jan 1, 2012

By Tanm Engin, Ali Riza Tarakcilar, Derya Dispinar

"Nowadays, the casting industry is developing parallel with the information technologies (IT). Particularly the casting simulation software is being frequently used in foundry floors for casting quality control and optimisation. In this study, the filling and solidification analysis of a rolling roll manufactured by spherical graphite cast iron were carried out by Vulcan casting simulation software. The appropriate defect relieving suggestions were presented by anticipation of defects that may form during the casting process.IntroductionThe optimisation of a casting process has long been the most focused area in manufacturing plants. Many of the work involve not only the process itself but the cost as well. When it comes to the process, it is important to be able to control the defects that may form during casting.The casting process begins with the melting of a charge; followed by pouring into the mould cavity. One of the most important factors is the difference in the liquid/solid density which may lead to porosity. On the other hand, turbulence during filling is another significant factor in casting operations [1].During solidification, due to the density difference between liquid and solid, porosity might form which leads to crack-like defects. There are several other factors that may determine the quality of a casting such as segregation, inclusions, grain size and etc. However, porosity is one of the first parameters that can be easily determine and controlled by the help of simulation software. Simulation is a cost-effective tool in the optimization of process parameters and castings can be visually observed. Time loss and economic expenses could be minimized [2]."

Jan 1, 2012

By Pradeep kumar Jha, Manas Mohan Mahapatra, Sabin Kumar Mishra, Satish Kumar Ajmani, Satish C. Sharma

"Due to mechanical/ electrical failure in the C.C. line or inadequate availability of molten steel from coming ladle, sometimes one/two outlets of a multi-strand tundish in continuous casting unit is closed. Closing any of the outlets affects the flow distribution inside the tundish which in turn governs the quality of steel coming out. Hence it is important to study which of the outlets should be closed to have proper results in terms of flow behavior and inclusion removal inside the tundish. Present study aims at finding the effect of closing one or two outlets on flow behavior and inclusion removal in a multi strand tundish. It was found that closing the near outlet (outlet near to the inlet) increases the inclusion removal tendency than closing the other two outlets in a six-strand billet caster tundish (only three outlets are considered because of symmetry).IntroductionContinuous casting process transforms molten metal into solid on a continuous basis. This process is the most efficient way to solidify large volumes of metal into simple shapes for subsequent processing [1]. Molten metal is tapped into the ladle from furnaces. From the ladle, the hot metal is transferred via a refractory shroud (pipe) to a holding bath called a tundish. The tundish allows a reservoir of metal to feed the casting machine while ladles are switched, thus acting as a buffer of hot metal as well as smoothing out flow, regulating metal feed to the moulds and cleaning the metal [2]."

Jan 1, 2012

By Toshihide Takenaka, Takashi Matsui, Nao Murakami, Masahiro Kawakami

"Electrowinning of Ti have been investigated in a LiF-NaF-KF melt including K2TiF6 at 773-923K by applying electrochemical oxidation ofH2 gas as an anodic reaction. The cathodic behavior of titanium and the anodic behavior of H2 gas were studied by voltammetry in detail to clarify the electrolytic condition for the process. The electrowinning of Ti was carried out by potentiostatic _electrolysis. Steady electrolysis was achieved under the suitable electrolytic condition without breaking out the anode effect. Titanium metal was electrodeposited on a Ti cathode though the deposits were usually powdery. It is concluded that this process is potential if the morphology of the deposit can be improved.IntroductionTitanium has such good properties as high specific strength and high corrosion resistance. However, the availability of Ti has been limited because the price of Ti is much higher than those of other common metals, such as Fe and Al. The production process of Ti ingot from its ore is rather intricate so that the production cost is high. If the simpler process is developed, the production cost should be retrenched. Titanium metal is usually produced by the Kroll process, which consists of the electrowinning of Mg metal in molten salt and the chemical reduction of TiCl.i by Mg metal. The Kroll process is very elabrate, but not simple. Because the chemical reduction ofTiCl4 by Mg metal is highly exothermic, a considerable amount of energy is wasted.Titanium metal can be electrowon in molten salt bath in principle. A simpler and more effective process than the Kroll process may be realized by the direct electrowinning so that the electrowinning of Ti metal has been studied widely[ 1]. Some researchs progressed to a pilot plant stages [2], but the electrowinning of Ti has not been industrialized yet."

Jan 1, 2000

By M. Sripathy, K. V. Sharmal

"The conventional fiber reinforced plastic does not participate in the plastic deformation or enter the large plastic deformation state during collision. On the other hand, sandwich structure allows more plastic deformation, which improves the energy absorption efficiency. The objective of this study is focused on the investigation of the crushing of sandwich structure made from sisal / coir / bamboo/ glass fabrics as reinforcement and with polyester resin to form the composites skin and with polyurethane foam as the core. Experiments were conducted, showing that the underlying crushing mechanism of sandwich structures is very different from that of solid-section thin-walled structures. When a sandwich is subjected to crushing, the core deforms in the shear mode and the face bends independently. The damage is through the width zone of crushed foam core accompanied by a residual crushing in the foam. It is shown that such damage causes a significant reduction of compressive strength. Results show that glass/polyester and bamboo/polyester skin based sandwich structures have superior compressive strength. Coir /polyester based sandwich structure come next to glass/polyester sandwich structures in this aspect which is then followed by Sisal /polyester based sandwich structures.IntroductionCellular polymeric foam sandwich structures are often employed in shock mitigating applications. The cellular polymeric foam has several favorable properties, such as, low density, relatively high strength-to weight ratio and a significant degree of crushability. This high crushability is the result of the large void ratio in such materials, which also facilitates the collapse of cell walls via bending and buckling [1]. A few feasibility studies on FRP sandwich panels show that the panels efficiently provided high mechanical performance for minimum weight [2]."

Jan 1, 2012

By Rzyman Michal, Nakamura Takashi, Shibata Etsuro, Grabda Mariusz, Oleszek-Kudlak Sylwia

"Tetrabromobisphenol A (TBBPA) and many systems based on the synergistic effect of brominated organic compounds with Sb2O3 are extensively used as effective brominated flame retardants (BFRs) in many materials such as plastics and textiles. Thermal degradation of BFR containing plastics leads to the formation of hydrocarbons and gaseous compounds such as HBr and SbBr3. Our thermodynamic considerations indicate that these gases can act as bromination agents for metallic oxides such as ZnO, Cu2O, CuO, PbO and FeO. Moreover, these metallic oxides have the thermodynamic tendency to brominate easier than does Sb2O3. The aim of this study was to investigate experimentally the reactivity of ZnO with 1) HBr originating from the thermal decomposition of TBBPA and 2) SbBr3, which is formed during thermal degradation of brominated flame retardant plastics. The thermal treatments of the mixture of compounds of interest were investigated by thermogravimetry coupled with mass spectrometry.IntroductionTetrabromobisphenol A (TBBPA) and many systems based on the synergistic effect of brominated organic compounds with Sb2O3 are extensively used as effective brominated flame retardants (BFRs) in materials such as plastics and textiles. For instance, 4.5 million tons of flame retardant plastics containing BFRs are produced in Japan each year. Thus, in thermal treatments such as the incineration and melting of solid wastes, BFR containing plastics are intentionally or unintentionally included in the wastes. Thermal degradation of BFR-containing plastics leads to the formation of hydrocarbons and gaseous compounds such as HBr and SbBr3 [1-5]. Our thermodynamic considerations [6] indicate that heavy metal oxides such as ZnO, Cu2O, CuO, PbO and FeO should easily react with HBr prior to Sb2O3 and also with SbBr3, the main gaseous product in the thermal decomposition of TBBPA, forming low boiling point metallic bromides suitable for the volatile separation of heavy metals. The metal oxides are also expected to qualitatively and quantitatively affect debromination and decomposition of the flame retardant."

Jan 1, 2008

By Jeffrey Shepherd, Scott R. Smith, Eduard Guerra

"Electrochemical and spectroscopic evidence for the dissolution of a Au electrode by meso-2,3- dimercaptosuccinic acid (DMSA) from an acidic LiCl04 electrolyte is presented. Near the potential of zero charge, DMSA was determined to form a stable layer on the metal surface but at more anodic polarizations, DMSA was displaced from the metal through an oxidative process. The anodic displacement of the layer from the electrode resulted in a small amount of Au that was detected in the electrolyte using atomic absorption analysis. The extent of Au dissolution, was monitored while holding the potential of the electrode for 24 hours at the thermodynamic Eo/H,O in LiCl04 electrolytes containing 10 mM DMSA. This routine resulted in detectable quantities of a soluble Au-DMSA complex in the electrolyte and the greatest leaching was observed at a pH = 2.0. At room temperature, the leaching rate was stable at 10.9 µg cm·2 hr·' however, upon increasing the temperature to 50.0°C, the rate of Au dissolution increased yielding an average rate of extraction of 40.1 µg cm·2 hr- 1. Interestingly, after the first 12 hours of leaching at 50.0°C, the leaching current decreased dramatically suggesting surface passivation which prevented further Au extraction. The implications of this process in the industrial leaching of Au will be discussed.IntroductionThe use of cyanide in the industrial process of leaching Au from ores has raised concerns regarding both operational safety and environmental issues surrounding the disposal of spent leaching eftluents in tailings ponds. Depending on the chemical nature of the processed ore, the spent solutions that are released into the tailings ponds can contain toxic cyanide, either dissolved or complexed with different metals and may pose serious risk to wildlife as well as freshwater contamination to nearby water systems. Because of these issues, some recent studies have focused on the exploration of more environmentally-friendly molecules to selectively leach Au with appropriate kinetics. However, to effectively leach Au into an aqueous solution, a suitable ligand that reacts to form a stable chemical bond with Au is needed to form soluble Au complexes that can be later recovered [I]. Recently several sulfur bearing alternatives have been shown to leach significant quantities of Au in aqueous solutions. These include thiourea [2], thiocyanate [3], and thiosulphate [4]. However, alkylthiols are also known to quickly form a stable covalent Au-S bond [5], but have been relatively understudied in term of their ability to leach Au in solution, even though some short chain thiols are water soluble and relatively nontoxic."

Jan 1, 2012

By Alex I. Kociubczyk, Wilky Desrosin, Lucía Mabel Boycho, Alicia E. Ares, Carlos E. Schvezov

In the present research, commercially pure Sn and Zn, and Sn-Zn alloys (Sn-1wt.%Zn, Sn- 2wt.%Zn, Sn-4wt.%Zn, Sn-8wt.%Zn and Sn-8.9wt.%Zn, weight percent) were obtained by a horizontal directional solidification process with two opposite senses and heat extraction. The solidification process was realized using a horizontal furnace with two heat extraction systems at both ends. The temperature was measured using eight K-type thermocouples and an electronic recorder of temperature data. The resulting structures were analyzed using optical microscopy. From the solidification process the thermal and metallographic parameters were determined in all samples. The presence of defects in the solidified pieces was observed. Internal defects pretended to be dependent not only on the composition of the alloys under consideration but also on the size of the structures formed, also, on the velocities and accelerations of interphases, and on the variation of thermal gradients. A model of the phenomenon from the first principles is presented.

Jan 1, 2015

By R. D. Osmanson

A series of batch roasting tests was performed on minus 1/2 inch gold bearing refractory samples from the Gold Acres deposit, and 67 select particles were polished and the sulfide alterations were examined microscopically. The suite of specimens represents two hour batch roast treatments at 600°C, 700°C, 725°C, 750°c, 800°C, and 900°C. Auriferous pyrites were found to alter sequencially to pyrrhotite, magnetite and finally to hematite. It was found that the decrease in cyanidation extraction with high temperature roasting is likely due to the increas ing stability of magnetite and more crystalline hematite, and the decrease in porosity with these phases which occlude the gold. Gold has been noted to occur very early in the mineralizing sequence, with gold being found in quartz and in clay/carbonate rock matrix. No gold was found in the two pyrite phases, but numerous gold grains were found in pyrrhotite after pyrite and in subsequent iron oxides. Gold mineralization had apparently ended by the time base metals were introduced into the deposit.

Jan 1, 1987

By Helena Byrdziak

Polish Copper Industry, located in the Lepica-Glogów region and operated since the 1970's, includes four mines and two smelters, "Legnica" and "Glogów", the latter consisting of "Glogów" I" and "Glogów II" both having different technologies. The "Legnica" and the "Glogów I" smelters using shaft furnaces, so sulfur elimination largely takes place during batchwise converting, resulting in fluctuation SO2-concentration between less than 1% up to 10% in the converter pas W the sulfuric acid plants. The ensuing difficulties of the past have now largely been overcome. Introduction of flash smelting at "Glogów II" with subsequent acid making by double SO2-conversion from the stable process gas, contributed significantly to further reduction Of SO2-emission. In 1994 a new double conversion sulfuric acid plant was installed at "Glogów l" as well as a "Solinox" desulfurisation plant at "Legnica", further reducing SO2 emission considerably, The next step towards this goal under consideration is a semi-dry desulfurization system for the "Glogów I" power station, SO2- abatement measures by KGHM and the results thereby achieved are presented.

Jan 1, 1996

By Claude Lorenson

"The Spyrometer™ imaging pyrometer brings new dimension of imaging capabilities to temperature measurement technology by combining a high temperature video camera with scanning optical pyrometry. This gives the operators the ability to observe process conditions while measuring the temperature of virtually any object or region in the field of view. Since the lens tube of the camera can be air or water cooled, it is possible to see inside furnaces giving a very good view of many different types of metallurgical processes. Specific benefits in process knowledge and maintenance tasks for furnaces in different types of metal industries are discussed.1-Principles of Imaging PyrometryLens tube, camera and processorImaging pyrometry is the combination of video imaging and computer-driven pyrometry that measures the temperature of certain zones (selected by the operator) within the image viewed on the monitor screen. To obtain a detailed image of the metallurgical process under observance, it is necessary to place the optical objective of the camera close to the process. The Spyrometer™ (which is Quadtek's tradename for its imaging pyrometer) objective is housed in a lens tube that is cooled and permits insertion inside the vessel of interest. The length of the lens tube is chosen on the basis of making sure that the tip of the tube is just beyond the refractories lining the inside of the furnace. In most pyrometallurgical processes, we have found that the most reliable system set-up uses a water cooled shroud to cool the lens tube optics. A sapphire window provides maximum protection from the environment. Even in the case of the water cooled version, there is an air purge for the lens that keeps the objective clean and protects against hot metal splashes."

Jan 1, 1997

By Weng Fu

In this study, Resin-in-Pulp (RIP) technology is used to separate Pb from a chalcopyrite slurry. Solvent-impregnated resin, Lewatit® VP OC 1026, which contains di(2-ethylhexyl) phosphoric acid (D2EHPA) in a macroporous polystyrene matrix was used, as the functional group exhibits selectivity for Pb over Cu. Adsorption pH, kinetics, as well as resin and CuSO4 concentrations were investigated. The results show that the kinetics of Pb and Cu loading are fast, reaching the adsorption equilibrium within 30 min. The equilibrium pH of 2 was chosen as optimum for operation in order to achieve a high Pb extraction rate and extent as well as selectivity for Pb over Cu. High Cu(II) concentration in solution results in Pb(II) requiring a larger amount of resin for the same degree of extraction. Regeneration and reuse tests show that the loss of adsorption capacity happens in the 1st and 2nd cycles and then the adsorption capacity stabilises for the 3rd cycle.