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By Yu Hu, Gabriella Tranell, Song Zhang, Eivind Johannes Øvrelid

"In the present research, recycling feedstock of silicon for Photovoltic (PV) application is investigated. Whether these recycling feedstocks are reliable in the future use is discussed in this work to assess the properties of the crystal silicon ingot, which is commercially pulled from top-cuts of casted multicrystalline ingot via one kind of Czochralski method - FerroTech. Dopant is the acceptor type Boron (B) and growth direction was <100>. Crystal diameter and the length were 190mm and about 1700mm, which were controlled by the temperature and the pulling speed, then cut to 156mm * 156mm wafers with 2000um and 200um thickness. Resistivity measurements of these wafers by Four Point Probe (FPP) are in good agreement to the calibrated profile after Rapid Thermal Process (RTP). In this work, the Minority Carrier Lifetime MCI, shown by Carrier Density Image (CDI) and Quasi Steady State Photo Conductance (QSSPC), gives the mapping results on the cross section and the relationship to the injection level, increases in an arrange from 40us to 90us along the ingot height, which is abnormal distribution compared to the standard ingot. Then Oxygen and other metal impurities distributions, measured by Flourier Transform Infra - Red (FTIR) respectively, account for the novel phenomenon of the continuously increased MCI. Various types of heat treatments were performed on these wafers (different ingot and different positions) in N 2 and 0 2 mixture atmosphere. Before and after heat treatment, micro-defects were revealed by copper decoration and etching work. Solar cells are fabricated by Energy Research Center of the Netherlands from the experimental ingot, and processed under an industrial standard line. Compared to results of the reference mono-crystalline and multi-crystalline silicon solar cells, the performances of experimental ones show excellent efficiency values up to 18.5%, and Jsc values up to 37mA/cm2.IntroductionThe PV industry has gone through rapid development, with a high growth rate resulting in an increasing demand for silicon feedstock. In addition, costs in production need to be reduced such that solar energy can compete other conventional and renewable energy. Searching low cost, reliable and efficient feedstock is one promoting way to improve and enhance the competitiveness of the PVindustry.More and more researchers start searching new raw materials for PV application [1]-[4]. The key to make full use of low cost raw materials is to control the distribution and effect of impurities, such as Carbon, Nitrogen, and other metal contamination [5]."

Jan 1, 2013

By John A. Clark, Danylo Oryshchyn, Casey Carney, Stephen Gerdemann, Cathy Summers, Thomas Ochs

"Limited analysis of combustion gas streams where carbon capture is not of interest is done mainly to ascertain operation parameters. Stringent regulations on acid gases and particulates promote careful flue gas analysis. Unregulated components are typically not analyzed. Typically not more than four points (two in the boiler, and one each in the flue and the stack) are sampled. A successful oxy-fuel process with carbon capture and compression is anticipated to require as many as 12 sample points with analysis for water, nitrogen, oxygen, argon, NOx, SOx, and carbon monoxide. Carbon dioxide captured for beverages produces a high value product and the cost associated with analysis is warranted. However, carbon capture for disposal must keep all costs to a minimum. This paper will compare alternative approaches for cost-effective sampling and analysis of the carbon dioxide product streams from oxy-fuel combustion, through all stages of production through compression and pipeline/vessel delivery.IntroductionAnalysis of gases in an oxy-combustion process with carbon capture is essential to the operations of the oxy-fired boiler and the subsequent collection, compression, and purification of carbon dioxide. The process is charged with pure oxygen and not-so-pure carbon in the form of coal at the front end, generating a product of mainly carbon dioxide with traces of argon, nitrogen, sulfur compounds, nitrogen compounds, oxygen, hydrogen, and mercury. It is possible that hydrogen chloride and hydrogen sulfide may also be present in trace amounts [1]. The trace components primarily come from impurities contained in coal such as water, sulfur, nitrogen, and volatile organic compounds. Coal also contains a good deal of mineral matter that is transformed into ash during combustion, becoming particulates that can complicate the analysis regimes utilizing standard analytical equipment."

Jan 1, 2010

By T. J. White

Each year, thousands of tons of toxic concentrates are produced as the unwanted byproducts of industrial operations and smelting activities. The fate of these materials remains open, as in general their consumption is limited and potential markets contracting. Xtaltite (pronounced crystal-tight) is a Synthetic Mineral Immobilization Technology (SMITE) optimized for the concentration, detoxification and consolidation of toxic metal wastes. In this approach, we seek to mimic nature to produce durable synthetic minerals that survive for aeons in well characterized geological settings. This approach has high public acceptability because the concept is easily understood by the layperson and the long term stability of the waste form may be predicted with confidence. In addition, where Xtaltite is used for mine backfill, a system of ecologically sustainable mining development is established. This paper details the design and fabrication of Xtaltite under oxidizing and reducing conditions. To illustrate and contrast these stabilization regimes, specific reference will be made to the treatment of thallium, chrom~um and arsenic wastes. Waste form performance under TCLP, dynamic boiling water tests and in other leaching media will be compared and discussed with respect to their relevance to different disposal options.

Jan 1, 1995

By R. W. Adams

A new process has been developed for leaching zinc sulphide concentrates at atmospheric pressure using air or oxygen plus nitrogen dioxide in dissolved or gaseous form as? an oxygen carrier. The process is flexible and can cope with variations in the degrees of retention and regeneration of dissolved nitrogen dioxide in the leaching phase. By controlled addition of concentrate a leach solution with low residual nitrate concentration can be produced. Following separation by filtration of unleached solids and elementa1 sulphur and conventional oxidation/precipitation of dissolved iron, the leach liquor can be treated with metallic zinc to remove the remaining nitrate and other meta111c impurities such as copper, cadmium and cobalt to provide a solution suitable for electrolytic recovery of zinc. Pilot scale testing of the process .has given zinc recoveries in the high nlnet1es, production of a hi.gh grade jarosite-free Pb/Ag residue (50% Pb.) and a saleable high grade of elemental sulphur. .A wide range of concentrates can be treated containing substantial levels of lead and copper as well as zinc. Indicative cost estimates suggest that the new process is competitive with alternative procedures such as pressure leaching.

Jan 1, 1990

By Florian Kongoli

The behavior of cobalt as a by-product in the NilCu smelting and converting processes effects directly the quality of the final products as well as the revenues gained from the overall process. An effective way to evaluate and predict this important behavior is thermodynamic modeling which reduces the time and the cost of experimental investigation. In this work a thermodynamic model of cobalt-containing matte phase in NilCu smelting and converting processes is presented. The model predicts a priori the thermodynamic properties and phase relations of the ternary and multicomponent matte based solely upon the optimized parameters of the binary systems. This model can be used with other models such as those of slag, metal, gas etc. to predict various aspects of cobalt behavior such as matte- slag, metal-slag distribution, etc.

Jan 1, 1999

By F. H. (Sam) Froes, C. Suryanarayana, K. C. Russell, C. M. Ward-Close

"Far from equilibrium synthesis allows development of novel crystal structures and microstructures, leading to achievement of enhanced physical and mechanical properties. A number of ""far from equilibrium"" techniques are reviewed with emphasis on the amount of departure from equilibrium. The ability of two such techniques, mechanical alloying (MAl, and physical vapor deposition (PVD) to develop novel structures are discussed in detail. For the MA process emphasis is placed on intermetallic compound compositions. Solubility extension, beyond rapid solidification (RS) levels, is found in terminal compositions but not for the intermetallics. Nanostructure-sized grains (< 100nm) form which can be retained after ""low temperature"" compaction. On continued milling in many cases the nanometer-sized grains transform to an amorphous structure. Ordering is destroyed by MA, except in those intermetallics with large negative enthalpies of formation. For the PVD process, a review of application to terminal light alloy compositions is presented. This includes a new high-temperature aluminum alloy, layered materials with nanometer spacing, corrosion-resistant magnesium alloys and low-density titanium compositions. IntroductionTo enhance the mechanical property combinations of advanced structural materials innovations in process/synthesis are required [1-6]. In this paper the capability of various ""far from equilibrium"" synthesis techniques [7,8] to produce novel constitutional and microstructural effects, and hence potentially enhanced physical and mechanical properties, in advanced materials is presented. The application of two such methods, mechanical alloying (MA) and physical vapor deposition (PVD) is discussed in detail. For the MA process emphasis is on intermetallic compositions with consideration given to solid solubility extension, microstructural refinement, amorphization, and formation of intermetallic compounds. For the PVD process application to terminal light alloy compositions is discussed."

Jan 1, 1994

By Gus Van Weert

Solvent extraction of iron from zinc refinery liquors has been investigated before, mainly on the MEHPA / HC1 stripping combination. Leakage of chloride into the zinc electrolyte and the costs of handling the ferric chloride eluate have prevented this option from being adopted. This work explores the stripping of the ferric loaded organic phase with nitric acid to take advantage of the possibility of regenerating up to 6N nitric acid, and clean spheroidal hematite production by autoclave treatment of ferric nitrate solution. The work was carried out with DEHPA (di 2-ethyl-hexyl phosphoric acid) in kerosine. Degradation testing proved the DEHPA to be very stable, when exposed to nitric acid solutions up to 6N and temperatures up to 70" C over a period of five days. Ferric iron was removed completely froma synthetic hot acid leach liquor, irrespective of the DEHPA concentration. Stripping the ferric turned out to be the problematic step. Although the stripping efficiency was considerable better at 50 than at 20° C, it decreased with increasing DEHPA/Fe ration in the organic phase. Eluates of no more than 5-10 g/l ferric nitrate were produced. surprisingly, nitric acid was found to be a less efficient stripping agent than sulphuric at equivalent normality and its efficacy levelled off above 4N. It was concluded that DEHPA does not appear to be the S.X. reagent to take advantage of the low cost autoclave decomposition of ferric nitrate opportunity in zinc hydrometallurgy and that another S.X. reagent, also resistant to nitric acid, but based on weaker compound formation is needed.

Jan 1, 1998

By Xu-ling Chen, Qian Li, Yong-bin Yang, Zhao Jing, Tao Jiang, Guang-hui Li

"It is generally known that alkali metals are harmful to blast furnace production resulting in aggravating RDI of sinters, abnormal expansion of pellets, deteriorating blast furnace lining, etc. Sinters regarded as dominating burden of blast furnace are determined as the main source of alkali metals. In this study, the removal behavior of potassium and sodium oxides by pre-reduction sintering during the sintering process was studied. The removal ratio ofK20 and Na20 was greatly influenced by coke powder content, carbon species, coke powder adding ways, additive and so on. Under the conditions of carbon rate 12% and 5% dosage of CO supplied in the sintering process, the corresponding removal ratio ofK20, Na20 was 69.00% and 32.79%, and metallization ratio could reach 4.65%. This technology provided a novel process for reducing the content of alkali metals in sinters and dramatically improving the quality of blast furnace burden.IntroductionSinter is the main iron-bearing charge of blast furnace for iron-making in China, making up about 80% of the total burden; therefore, its quality has a significant influence on the quality of pig iron and blast furnace operation. Research and practice of numerous years prove that potassium and sodium coming from ores are brought into blast furnace and upgraded, which is one of the essential reasons that lead to blast furnace nodulation and influences its strength. Currently, effective flow sheet to remove potassium and sodium is weak magnetic separation-intensive magnetic separation-flotation [l], while iron ore concentrate is still ofhigh levels of potassium and sodium. As sintering process is also not effective to remove potassium and sodium, blast furnace in China is of high alkali burden, e.g. it reaches 5.6-6.2kg/tFe in Baotou iron making plant, which is greater than international tolerated level of2.55kgltFe [l]."

Jan 1, 2013

By Edgar Peek

Lixiviant regeneration is by definition a precondition for any hydrometallurgical process. In chloride hydrometallurgy either HCl or Cl2 has to be regenerated in order to establish an economically viable metallurgical process. One such regeneration process is widely used with steel pickling where HC1 is regenerated through the thermal decomposition of ferrous chloride in either spray roasters or fluid bed pyrohydrolyzers. This standard HC1 regeneration process deserves to be considered as a potential separation process, since thermodynamic calculations show that a fluid bed pyrohydrolyzer can function as a ferrous-nonferrous separator. Several nonferrous,metals such as zinc, lead and cadmium can be volatilized as a chloride under ferrous chloride pyrohydrolysis conditions. If such a nonferrous metal volatilization could be achieved in the case of slurry feeding of "contaminated" iron oxides, then this would increase the Fe/H2O ratio of the (process) feed and thus save on fuel per ton of iron, while yielding a marketable iron oxide product. Previous test work on synthetic materials revealed that the near-complete separation of zinc, lead and cadmium from iron oxide was possible in a pyrohydrolytic atmosphere, even if zinc was present as zinc ferrite (more than 99.5%). This investigation, which was carried out in a tube furnace at 1100 K has now been extended to treat synthetic zinc minerals and also franklinite ore. For the latter, it was found that 85% zinc volatilization could be achieved in 4 hours at 1300 K. It is postulated that complete zinc volatilization could not be attained due to the formation and/or presence of gahnite and hardystonite, which might be stable in HCl/H2O atmospheres at 1100 K. The effect of adding small amounts of calcium chloride to react with gahnite and hardystonite to give zinc chloride and both calcium aluminates and silicates is being discussed. Test work on slurry feeding of this complex ore in a recently constructed 4-inch diameter fluid bed pilot unit has been planned for the near future.

Jan 1, 1995

By Stanko Nikolic

The Top Submerged Lance (TSL) technology, developed in the 1970s, is now widely used for the processing of a range of materials. TSL technology for continuous converting was first patented in the 1990s. The process is based on the use of calcium ferrite slag. Although this slag system had been applied elsewhere the phase equilibria had not been thoroughly investigated. This lead to a collaboration between the Process Technology group of Mount Isa Mines, now part of Glencore, and the Pyrometallurgy Innovation Centre (PYROSEARCH) at The University of Queensland. Through multiple research programs this complex system was successfully investigated. The results were then implemented within thermodynamic modelling tools. This combined new knowledge was then applied to the design and industrial implementation of the TSL continuous converting technology, ISACONVERT™. This paper describes the key findings of the research and how this was applied to the industrial implementation of the technology.

By Reza Kamali, Mohsen Bashiri, Hadi Fanisalek

"Nomenclature: A: area (m2), C: heat capacity (WIK), cp: specific heat (J/Kg K), d: internal tube diameter (in), F: correction factor for multi-pass and crossflow heat exchanger, h: convective heat transfer coefficient (W/m2K), k: thermal conductivity (W/mK), L: length (m), m: mass flow rate (Kg/s), W: flow rate, N: number, Q: heat rate (W), R: thermal resistance, T: temperature (°C), U: overall heat transfer coefficient (W/m2K), ;1,,P: pressure drop (Pa), ;1,,T: temperature difference (°C), p: density (lb/ft3), N: number of tube passes, U,: velocity in tubes, iJh: head loss in feet of flowing fluid, Up: velocity in the pipe leading to and from the heat exchanger (ft/sec), µ: viscosity ( cp ), Llpf frictional pressure loss (psi/l 00 equivalent ft of pipe) Subscripts: b: baffle, c: cold, cf counter flow, ex: exchanger, f: fouling, h: hot, i: inlet-inner, ib: inlet baffle, lm: logarithmic mean, m: mean, o: outlet-outer, s: shell, t: tube, w: wall AbstractThe main bottleneck for primary aluminum production industry is dealing with a huge amount of input energy. The fact is that part of provided energy to aluminum production smelters will be lost as waste heat and it never used for aluminum production. One part of waste heat is escaping from the potroom exhaust gases, which was studied for possible recovery in a desalination plant to produce distilled water and the paper was presented in 2011 TMS Annual Meeting. However, it was shown that waste heat recovery plant to produce distilled water is highly profitable but the main fact is that the exhaust gases from potroom are highly corrosive, abrasive and dusty. The main challenge for desalination plant construction, which is using aluminum smelter exhaust gases as the main heat source, is the highly corrosive environment that makes the situation difficult and complicated for equipments design and plant construction. In this paper, we are trying to study a detailed investigation regarding the heat exchangers fouling, corrosion in heat exchangers including heat exchangers' material, how often we need to shut down the plant for maintenance or cleaning, and plant thermal efficiency with considering fouling."

Jan 1, 2012

By Metehan Erdogan, Ishak Karakaya, Fuat Erden

"Mg-Ni system draws attention due to the promising hydrogen storage properties of Mg2Ni. The proposed method involves the use of NiO and MgCl2 in an electrochemical cell to from Mg-Ni intermetallics directly. The electrodeoxidation of NiO was followed by combination of Mg and Ni in molten salt electrolytes. The products were characterized by XRD analysis and SEM examinations. The quantitative results from Rigaku supported by Rietveld Refinement method conducted by Maud showed that more than 50 percent of the input Ni was converted to Mg-Ni intermetallics.INTRODUCTIONIt is well known that fossil fuels are the most common energy producing materials throughout the last century although, they are not renewable and their usage cause critical environmental problems [1, 2]. Hydrogen, on the other hand, is known as a clean, renewable energy carrier and instead of fossil fuels; usage of hydrogen for energy production will be the benefit of mankind. However, there are problems that hinder more common usage of hydrogen such as hydrogen storage [3]. Mg2Ni is known as Mg based hydrogen storage material with high hydrogen storage capacity [3-6]. Common Mg2Ni production methods are; mechanical alloying [8-11], vacuum induction melting [12, 13], vacuum arc melting [14], combustion synthesis [15], melt spinning [16], repetitive rolling [17] and isothermal evaporation casting [18] were also used. However, in all of these, pure Mg and Ni are required to be produced previously. Therefore, difficulties arise during handling, preparation and combination of Mg and Ni due to highly reactive nature of especially magnesium (i.e. oxidation of Mg) [11, 17, 19, 20]. Although hydrogen desorption dynamics can be significantly improved with usage of nanostructured Mg2Ni [7], it is difficult and it requires very long processing durations to produce nanostructured Mg2Ni by above processes."

Jan 1, 2014

By Ryokichi Shimpo, Akio Fuwa

"The process-measurements of copper smelters in Japan were investigated for the summary of the latest technique and for the fundamental study of process control. The smelters investigated are those employing flash smelting furnace and P.S. converter, one reverberatory furnace and P.S. converter, and one continuous smelting converting furnace (M.I. process). Respective process is then considered, consisted of several reactors of different functions. The measurement methods were summarized in each reactor, including the measurement points. The methods of chemical analyses of the samples in each reactor were also investigated.IntroductionAn investigation on the process measurements, chemical analyses, and system control in copper smelters in Japan were carried out for understanding and summarizing the technique of the pyrometallurgical copper smelting operations. The typical seven processes in six copper smelters were investigated in the period from 1985 to 1987. The smelters investigated were Touyo Smelter of Sumitomo Metal Mining Co., Ltd., Kosaka Smelter of Dowa Mining Co., Ltd., Saganoseki Smelter of Nippon Mining Co., Ltd., Tamano Smelter of Hibi Kyodo Smelting Co., Ltd., Ashio Smelter of Furukawa Co., Ltd. and Naoshima Smelter of Mitsubishi Metal Co., Ltd. They include five flash smelting furnace and P.S. converter systems, one Mitsubishi continuous smelting and converting process (M.I. process), and one reverberatory furnace and P.S. converter system.The investigation was performed by making inquiries about the measurements, chemical analyses, system control, and their future prospects to the engineers in each smelter and by summarizing up in each item. The system control and future prospects were summarized in another paper titled ""Process Control Scheme of Copper Smelting Processes in Japan and Future View."

Jan 1, 1989

By S. J. Macnaughton

The Olympic Dam deposit in South Australia contains 2% copper and 0.06% uranium, which are present as bomite, chalcocite, chalcopyrite, uraninite, coffinite and brannerite. The copper is principally recovered using flotation. The flotation tailings, which contain the bulk of the uranium, and typically 0.3% copper, are leached using sulfuric acid and an oxidant at atmospheric pressure. This paper describes the results from a detailed investigation of the leaching behaviour of this ore. The influence of acid strength, Fe3+ concentration, redox potential and temperature on the dissolution of uranium and copper minerals was studied. Experimental data were obtained from extensive batch leach tests. Mineralogical studies, including SEM analysis of individual mineral grains, were also carried out. The maximum extraction of uranium determined experimentally was in good agreement with that predicted from SEM determination of the proportion of refractory brannerite in the ore. The leaching rate of copper was found to be independent of acidity over the range 20 g L-&apos; to pH 2.0, but was strongly dependent on temperature and Fe3+ concentration. Uranium extraction showed a weak de endence on acidity, Arrhenius temperature dependence and a complex co-dependence on F>+ concentration and redox potential. A kinetic model has been developed, which predicts copper and uranium dissolution. This model will be incorporated into a more comprehensive model that can be used to predict leach performance and reagent consumption for specific ore samples.

Jan 1, 1999

By William Petruk

The primary requisite for a successful extractive metallurgy operation is to grind an ore fine enough to liberate the minerals so that they can be concentrated, or to expose mineral surfaces so that the minerals can be leached. The ease or difficulty of liberating or exposing the mineral grains is dependent upon the mineral textures such as grain size, crystallinity and bonding between mineral grains. In particular, mineral grains with straight grain boundaries and a weak bonding to other minerals are easily liberated and readily concentrated into high grade concentrates. In contrast mineral grains that have re-entrant boundaries and are strongly bonded to their neighbours are not easily liberated and will not produce high grade concentrates, even with regrinding. Similarly, inclusions that occur along fractures and grain boundaries can be readily exposed and leached. Whereas minute random inclusions in large grains will not be liberated or exposed unless they occur along planes of weakness.

Jan 1, 1995

By Yuanbo Zhang, Zhixiong You, Daoxian Duan, Guanghui Li, Tao Jiang

"Manganese is mainly consumed by steel and battery industries. In recent years, it is essential to utilize the low-grade manganese oxide ores with total manganese grade below 25%, as the high quality manganese ore resources are becoming scarce with the rapid development of the steel industry. Conventional pyro-metallurgical processes for utilizing manganese oxide ores are characterized by high production cost and energy consumption, low productivity, serious environmental pollution, etc. In this study, reduction thermodynamic of MnO2 reduced by sulfur was firstly carried out. Then, a novel process of reduction roasting with sulfur followed by acid leaching was developed to recover manganese from the very low-grade manganese oxide ores. Effects of main factors, including temperature, reduction time and S/Mn mole ratio, were investigated, and a high leaching efficiency of Mn above 95% was obtained under optimal conditions.IntroductionHigh/middle-grade manganese oxide ores are generally used in the metallurgical industries, particularly in steel plants and ferro-alloy units. The consumption of metal manganese in the ferro-alloy industry accounts for 85- 90% of the total Mn demanded [1]. Therefore, high quality manganese ore resources are becoming scarce with the rapid development of steel industry. It is essential to make good use of large quantity of low-grade manganese ores (TMn < 25%) presently available."

Jan 1, 2012

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. he special studies have been conducted in the Gintsvetmet 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 Thomas P. Battle

Ilmenite (iron titanate) is the source of over 90% of all the titanium produced in the world today. At some point during production of titanium dioxide or titanium metal the iron impurity must be removed. Too often it becomes a waste instead of a product. DuPont and MINPRO have developed a solid-state process which separates the iron and titanium components of ilmenite into different high-purity powders, which can be separated using conventional mineral processing techniques. The main reactor in this process is a unique high-temperature ball mill, where the iron segregates from the ilmenite lattice with the assistance of catalytic quantities of He\. The results of lab, pilot plant, theoretical, and scale-up studies are presented and discussed.

Jan 1, 1996

At its Copper Cliff Smelter, Inco Limited processes a bulk copper-nickel concentrate in two Inco oxygen flash furnaces. The furnace matte is converted to low iron matte for further processing, and the molten converter slag is recycled to the flash furnaces. The flash furnace slag is discarded. Natural gas or coke supplies a minor proportion of the process heat requirements, thus limiting the flash furnace matte grade to the target 45% CuNiCo. Coke addition to the furnace offers a potential means of establishing a reducing barrier on the surface of the molten bath. Such a practice would be conducive to producing sulfur deficient (partially metallized) matte. At the same iron content, the iron activity of sulfur deficient matte is higher than that of regular matte. A supernatant coke barrier could, therefore, be expected to lead to higher nickel and cobalt recoveries, reduction or even elimination of magnetite furnace bottom build-up and increased sulfur elimination as SO2 in the flash furnace. Preliminary experiments were conducted in a mini plant flash furnace to investigate the effect on process metallurgy of the suggested modified scheme. This paper presents the experimental results and discusses key aspects of the possible operation of the Inco flash furnace with a coke barrier separating the freeboard from the molten bath.

Jan 1, 2003

By Lucas L. da Costa, Sergio N. Monteiro, Romulo L. Loiola, Tammy G. Rodrigues Portela

"The fibers extracted from the petiole of the buriti palm tree are relatively strong as compared to other lignocelluloses fibers, with a potential for composite reinforcement. In this work, polyester matrix composites incorporated with these fibers were investigated for their flexural behavior. Specimens with up to 40% in volume of continuous and aligned buriti petiole fibers were bendtested until rupture. The results showed an increase in both the composite mechanical strength and the stiffness with incorporation of these fibers. A fractograph analysis by SEM disclosed a moderate adhesion mechanism between the buriti petiole fiber and the polyester matrix. This mechanism is apparently responsible for the improved performance of the composites.IntroductionIn recent years, the substitution of energy-intensive synthetic materials for natural ones is being considered in many industrial sectors including automobile, packing and textile [1]. A typical case is that of natural fibers, mainly those obtained from cellulose-based plants also known as lignocelluloses fibers. They have being investigated in the past two decades, aiming to replace synthetic fibers, particularly the glass fiber, commonly used as polymer composite reinforcement [2-8]. From the engineering point of view, lignocellulosic fibers present today important environmental, economical, societal and technological advantages already discussed [7-8]. Moreover, several lignocellulosic fibers are known since the beginning of our civilization and still cultivated or naturally extracted all over temperate and tropical regions of the world. According to Kalia et al [1 ], these fibers can be classified by their origin, as shown in Table 1."

Jan 1, 2011