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By Leila Figueiredo de Miranda, Leonardo G. de Andrade e Silva, Anderson dos Santos Mesquita

ThisworkseekstounderstandifPETcompoundswithcarbonblackcan be uses to replace polypropylene and polystyrene for anti-static packaging mate- rials. PETcompoundswerefabricatedcontaining10.0;11.0;12.0and15.0weight % of carbon black with a particle size 325 mesh. We determined the thermome- chanical properties (Dynamic Mechanical Analysis—DMA, Tensile Properties, Fracture Toughness, and Hardness) and Electrical properties of the compounds. In conclusiontheresultsshowthecompoundbased onPETfilledwith 15.0% carbon black might be used in the handling, transportation and storage of electronic components because their mechanical properties, thermal and resistivity are satis- factory for this purpose. (cid:1) (cid:1)

Mar 1, 2018

By Mark Tjerkstra

In ,1993, the WMC Resources Ltd.-owned Kalgoorlie Nickel Smelter, underwent a capacity upgrade. This capacity increase was offset by .air quality control restrictions limiting the smelter's availability to 80%. As the direct. result of this limitation, WMC Resources Ltd commissioned a double absorption contact ,acid ,plant for the desulphurisation of furnace waste gas in August 1996. The history and the impact of the acid plant on S02 emissions and air quality is reviewed. General descriptions of the other aspects of the Kalgoorlie Nickel Smelter's Environmental Project are also included in the paper. Information on 'the design features? and operating practices that relate to or contrast with practices at operations visited by KNS personnel prior to acid plant commissioning provide the paper's focus. Smelter operation has changed markedly from unstable operation prior to 1997 to continuous" operation with little down time due to mechanical or process failures resulting in increased smelter availability to more than 90%

Jan 1, 1998

By Isabela Leao Amaral da Silva, Felipe Perisse Duarte Lopes, Alice Barreto Bevitori, Sergio Neves Monteiro, Ruben Sanchez Rodriguez

"The fibers extracted from the stem of the ramie plant are among the strongest natural lignocellulosic fibers with a potential to be used as reinforcement of polymer matrix composites. Characterization of the ramie fiber has recently been conducted for its physical and mechanical properties. However, the effect of increasing temperature on the ramie fiber behavior has not yet been fully investigated. Therefore, the objective of this work was to perform a thermal analysis on ramie fibers with different diameters within the naturally found range of practical interest. The analysis was conducted by thermo-gravimetric, TGA and DTG, as well as differential scanning calorimetric, DSC, techniques. It was found that the ramie fibers present thermal stability up to 200°C and then suffer a sharp deterioration between 300 and 500°C, resulting in characteristic peaks.IntroductionSince the middle of last century, polymer composites have substituted many conventional monolithic materials in applications ranging from aerospace to sport [l]. The main advantages of these composites are the low density and flexible properties specially using fiber as reinforcement to suit the mechanical performance requirements [2]. These are usually high strength and stiffness requirements that could be reached with synthetic fibers such as glass, carbon and aramid fibers. In recent years, however, the use of synthetic fibers is being questioned in terms of problems caused to the environment. In fact, as non degradable material, synthetic fibers are associated with long term pollution when discarded. Moreover, the expended energy for fabrication and processing can be related to relatively large amounts of C02 emissions and represents a contribution to global warming [3]. Glass fiber, in addition, is toxic and cannot be incinerated as a waste in thermal power plants [ 4]. Possible substitutes for glass fiber are the natural fibers. Many natural fibers are today being considered as viable alternatives to replace glass fiber as reinforcement of polymer composites. In particular, some natural lignocellulosic fiber extracted from plants present a real potential for this replacement [2-8]. Their comparative advantages are lower density and reduced cost as well as renewability, biodegradability, recyclability and neutrality with respect to C02 emission [3]."

Jan 1, 2011

By Xuemei Zheng, Aiyuan Ma, Yonggang Zuo, Jinhui Peng, Shiwei Li, Libo Zhang

The effect of moisture content on the dielectric properties and microwave drying behavior of zirconium hydroxide was studied by using an open-ended sensor dielectric measurement system at the frequency of 2.45 GHz. The experimental results showed that moisture content can significantly influence the variation of dielectric properties. Dielectric constant, loss factor and loss tangent all increase with the increasing moisture content. Compared with the conventional drying method, the microwave-assisted drying method resulted in a substantial decrease (81.8%) in the drying time, and the drying effect was better at the lower power level of 600 W. This study offers the useful information on dielectric properties of zirconium hydroxide, which can be used for developing microwave drying applications in mineral processing and designing better microwave sensors for measuring zirconium hydroxide moisture content.

Jan 1, 2015

By John Anawati

Bauxite residue is an environmentally unfriendly byproduct of alumina manufacturing, produced worldwide in large quantities. This material contains 50– 100 ppm of scandium, a critical material for the production of stronger, weldable, corrosion resistant, and heat tolerant aluminum products. Aircraft manufacturers are particularly interested in Al–Sc alloys because of its ability to form weldable alloys that could potentially reduce aircraft weight by 15–20%. Because of its abundance and low cost, bauxite residue has the potential to be used as an efficient feedstock for valorization processes to recover its scandium content, while in turn degrading this problematic waste. In this project, we developed an efficient process to recover scandium and rare earth elements from a Canadian bauxite residue with high extraction yields, using industrially scalable and economical techniques. The process employs a modified version of sulfuric acid leaching and subsequent impurity removal by selective precipitation. This article outlines the current progress and design rationale in the development and optimization of this innovative and sustainable recovery process.

By J. K. Brimacombe

Plant trials have been conducted at the Tacoma Smelter of ASARCO to assess the effect on tuyere blockage and refractory erosion at the tuyere line, of increasing the injection pressure of air into a Peirce-Smith con¬verter. Four tuyeres each having an ID of 19.1 mm (3/4 in) were installed toward one end of the tuyere line of the No. 4 Converter. Air and oxygen-enriched air were injected at 414 kPag (60 psig) through these tuyeres and at the usual 83 kPag (12 psig) through the remainder of the tuyeres in an otherwise normal converter campaign. The test campaign consisted of 88 charges and lasted for 89 days. During this period, punching of the high-pressure tuyeres was found to-be unnecessary; and when, as a precaution, the tuyeres were cleaned by hand at the end of a charge, they were always open. Also it was observed that the flow of high-pressure air remained constant. Accretion formation around the tip of the high-pressure tuyeres varied from charge to charge and was influenced by the matte grade and the level of oxygen enrichment.

Jan 1, 1983

By M. Sakamoto, S. Karaswa, Y. Yoneoka, Y. Ohmizo

"The Annaka Refinery has been processing leach residue by Waelz process for 17 years. Recently, the quantity of the leach residue has increased due to a decline in the quality ~f zinc concentrate. Meanwhile, negative factors (e.g. deterioration of water balance due to improved electrolytic power consumption rate) have increased· in the processing of the leach residue.We have implemented various measures in responses to this situation, while striving to increase ·processing capacity and achieve stable operation. AS we have largely completed our assessment of the efficacy of these measures, we report on our recent process improvements.IntroductionWe have been treating leach residue by the Waelz kiln process since 1981. At that time, treatment of only 50,000 tons of leach residue per year was anticipated. However, subsequent process improvements have revised this figure up to 75,000 to 80,000 tons per year.However, today's increased Fe zinc concentrate grade has resulted in increased amounts of leach residue. In addition, improvements have reduced electrolytic power consumption rate of zinc electrolysis, limiting the amount of water that can be used in ·the zinc refining processes and for deaning leach residue. Consequently, we encounter an increasing number of problems and factors adversely affecting leach residue treatment, including increases in water-soluble Zn (WsZn) and. S (S04) in leach residue.To solve these problems, we have taken several measures to ensure long-term continuous operation and treatment of this increased · amount of leach residue. This paper discusses these measures."

Jan 1, 2000

By Kinya Atsumi, Kanjana Khunathai, Hisaya Kato, Hidetka Kawakita, Keisuke Ohto, Katsutoshi Inoue

"Crosslinked microalgae were prepared from the residue generated in the production of biofuel, by crosslinking-condensation in concentrated sulfuric acid. These microalgae were tested for adsorption of various metal ions in hydrochloric acid medium. The crosslinked microalgae exhibited high selectivity for Au(III) over other precious and base metal ions. From an isotherm experiment, the maximum adsorption capacity was evaluated to be 3.25 mol/kg of dry gel for Au(III) which was many times higher than that of the original microalgae residue. SEM and X-ray diffraction confirmed the formation of metallic gold particles, suggesting the occurrence of a redox reaction between surface functional groups on the gel surface and trivalent gold ion.IntroductionSubstantial quantities of precious metals are being used by the electronic industry because of their excellent electrical conductivity and resistance to corrosion. In recent years, recovery of precious metals from secondary sources such as electronic scrap [1,2 ], and leach liquors is being favored because of environmental concerns. Of course, recovery is only practical, if its cost is lower than the value of the metals (gold, platinum and palladium) recovered.Traditional methods of separation and refining do not fulfill this requirement. In order to overcome this problem, attempts have been made in recent years to develop new processes including total leaching in hydrochloric acid containing chlorine gas or hypochlorite, followed by solvent extraction and ion exchange [3]. In the new processes, new solvent extraction reagents or ion exchange resins with high selectivity and high loading capacity are used to simplify the process and to reduce the operating costs."

Jan 1, 2011

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 A. Hasko

Phytoremediation is a new low cost alternative technique for remediation of contaminated soils from heavy metals that are emitted by ferrous and nonferrous mining and extracting processes. It is based on the possibility to use several plants that accumulate high level of metals in order to remove metallic pollutants from soils and render them harmless. Phytoextraction is an adjacent new technique that uses these hyper-accumulator plants in order to extract the metals from them using even the conventional smelting or refming processes. In our previous work, an extensive investigation of about 150 plants have been carried and several species were identified that could be used for nickel phytoremediation and phytoextraction because of their high accumulation of nickel. It has been found that five taxa from Alyssum genus specie had the highest ability to accumulate nickel with concentrations more than 10000 ug/g (dry weight) or 1%. The taxa showing the highest accumulation of this metal is Alyssum murale var. chlorocarpum with 28 600 ug/g or 2.86%, a good candidate for Phytoextraction. In this work, in order to optimize the phytoremediation and phytoextraction processes further Absorption Spectrometry measurements and biological studies were carried out to determine the parts of the plants that accumulate the highest amount of nickel and the best biological cycle during which they accumulate the highest amount. The results show that the greatest accumulation of nickel occurred in the leaf material (2.86%) and the least in the roots (0.43%). The investigation of the biological cycle of the genus Alyssum showed that: (1) the seeds germinated between 50 C to 30 0 C and more in 25 0 C; (2) 62.9 % of seeds germinated at A.m. var. chlorocarpum; (3) the emergence is almost continue from March to April; (4) the anthesis occurs from May to July; (5) the ripening of the fruit takes place 30 days after flowering; (6) the dissemination of fruits occurs from September to October. Due to these special characteristics it is reaffirmed that Alyssum murale var. chlorocarpum, as a nickel hyperaccumulator, is the most promising plant to be used for feasible phytoremedation and phytoextraction purposes. Keywords: Key words: Phytoextraction, PhytoRemediation, Nickel accumulators, Alyssum sp., Biological cycle

Jan 1, 2003

By De-qing Zhu, Zi-fu Gao, Jian Pan

"In order to produce high quality metalized products and prevent from burden cohesion during pre-reduction, self-fluxed pellets were made for COREX process in the paper. The effects of reduction temperature and reducing gas composition on pre-reduction behaviors of self-fluxed pellets are studied. The results show that the prereduced pellets have poor quality and deposited carbon appears when the reduction temperature is between 600°C and 700°C. The metallization rate, reduction degree and compressive strength of prereduced pellets are promoted by the elevating reduction temperature and mole fraction of H2. Pellets reduced by pure H2 at 800°C have high metallization rate (96.2%), reduction degree (99.4%) and compressive strength (960N/pellet). In all tests, self-fluxed pellets display normal swelling (RSI<l5%) behavior which reveals that self-fluxed pellets are suitable for COREX process. Increasing reduction temperature and mole fraction ofH2 in reducing gas is benefit for pre-reduction of pellets.IntroductionCompared with Blast Furnace, the COREX process has advantages of short flow sheet, using non-coke coal and high-energy utilization. Acidic pellets and lump ores are the chief iron- bearing burden for COREX process which could lead to low melting point substance appearing in per-reduction process. In addition, the acidic hematite pellets tend to swell during the reduction [1-3]. This will result in decreasing compressive strength of pellets, burden cohesion, bad air permeability and poor work status in shaft furnace. Adding carbonate flux could restrain burden bonding to some extent in actual production, but decomposition of carbonate flux increases energy consumption. Worse still, weak reduction potential is unfavorable to iron material reduction [ 4, 5]."

Jan 1, 2013

By Catherine Williams-Beam

Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc. Its chemical behavior resembles the alkali metals (K, Rb, Cs). It occurs almost exclusively in natural waters the monovalent thallous cation. The solubilities of thallous compounds are relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. The major sources of thallium are the base metal sulfides and precious metal bearing sulfides. Therefore, it is often present as a contaminant constituent in waters emanating from heavy metal sulfide bearing deposits. Thallium can be effectively removed from wastewater to <2 µg/L by reductive precipitation of thallium sulfide. Effective thallium sulfide precipitation requires a controlled solution potential/pH combination. The required potential can be effectively achieved by utilizing a particulate iron slurry or packed column environment. Experimental results will be presented and discussed.

Jan 1, 2003

By Sang Han Son

The vapor pressures of FeCI2 and ZnC12 in the FeCl2-ZnCl2 system were measured by the transpiration method at 873K and 917K. The vapor pressure data were interpreted to indicate the formation of complex ions in the FeCl2-ZnCl2 melts. It is presumed that the complex molecule FeZnCl4 as well as FeCI2 and ZnCI2 exists in the vapors in equilibrium with molten FeCl2-ZnCl2 mixtures. The activities in the FeCl2-ZnCI2 system are shown a negative deviation from Raoult&apos;s law. These results suggest the formation of complex ions such as ZnCl42- in molten FeCI2-ZnCI2 mixtures.

Jan 1, 2003

By M. Jahazi, P. P. Bhattacharjee, K. Chadha

The present work investigated the effect of strain reversal during high pressure torsion on the evolution of microstructure, texture and hardness properties of two different materials with different dynamic recovery behavior, namely, high purity (99%) Aluminum (2N-Al) and Aluminum-Magnesium (Al-2.5%Mg) alloy. In the two aluminum alloys subjected to different routes, the evolution of the ultrafine structure followed same trend. At lower strain level, sub grains with prominent LAGBs network were observed and at higher strains, ultrafine equiaxed grains separated by HAGBs were observed throughout the disk. The texture evolution in monotonically and strain reversal processed 2N-Al and Al-2.5%Mg showed presence of typical torsion texture components at different strain levels. The strength of the components was observed to follow different trends depending on the processing routes.

Jan 1, 2015

By Tianzu Yang, Weifeng Liu, Shu Bin, Lin Chen, Wanda Bin

"Vanyukov Process has been mainly applied for processing copper and nickel sulfide ore for more than 30 years. Based on the understanding of the Vanyukov Process, researchers from China introduced the technology into the areas of lead, antimony and bismuth extraction by changing the furnace structure and technical flow, which greatly extended the application area and raised the processing efficiency, thus developed the oxygen-rich side-blow bath smelting (OSBS) technology in 2000. This contribution reviews the history of OSBS technology from four respects: the quantity, the furnace structure, the process flow and the application area. Its potential research direction and industrial application are also summarized.IntroductionVanyukov bath smelting furnace and related bath smelting technology were developed by researchers from Soviet Union who devoted comprehensive research on fundamental theory as well as engineering technology [1,5]. Vanyukov process has been applied for large industrial production since the 1970s and it is still one of the major methods in modem pyrometallurgy process. The appearance ofVanyukov double district furnace and joint double furnace in the past ten years, which are applied for copper smelting, is the most valuable advances of the Vanyukov process [7,8,9]. However, the application ofVanyukov process was limited in copper and nickel sulfide ore smelting, and few countries adopted this process except Soviet Union."

Jan 1, 2013

By J. R. Goode

Up to one half of neodymium and praseodymium production, key ingredients in permanent magnets, is produced illegally. About 60% of cobalt production, critical in lithium-ion batteries and other applications, comes from central African states, and much of it is produced illegally. Tantalum, important in modern electronics, is also primarily sourced from central Africa and, again, much of it illegally. Illegal mineral production, as exemplified here, is often used to fund armed conflict. Furthermore, it is typically conducted with scant regard for human rights and environmental protection. It also leads to depressed prices which in turn limits the possibility of legitimate producers entering the market. Systems of traceability and provenance, along with cooperative supply chain participants can limit the production of illegitimate material and thereby improve conditions in the countries of origin and reduce downward pressure on prices.

By Richard J. Abitz

Thennodynamic geochemical models have been applied to assess the relative effectiveness of a variety of reagents added to aqueous waste streams for the removal of radioactive elements. Two aqueous waste streams were examined: effluent derived from the processing of uranium ore and irradiated uranium fuel rods. Simulations of the treatment train were performed to estimate the mass of reagents needed per kilogram of solution, identify pH regions corresponding to solubility minimums, and predict the identity and quantity of precipitated solids. Results generated by the simulations include figures that chart the chemical evolution of the waste stream as reagents are added and summary tables that list mass balances for all reagents and radioactive elements of concern. Model results were used to set initial reagent levels for the treatment trains, minimizing the number of bench-scale tests required to bring the treatment train up to full-scale operation. Additionally, presentation of modeling results at public meetings helps to establish good faith between the federal government, industry, concerned citizens, and media groups.

Jan 1, 1996

By Shigehito Isobe

The Li-N-H system composed of LiH and LiNH2 catalyzed by titanium compound desorbs ~6 mass% hydrogen and a quite small amount of ammonia in temperature range from 150 to 250 °C under He flow atmosphere. In this work, hydrogen desorption (H-desorption) mechanism in the reaction from LiH+LiNH2 to Li2NH+H2 in a non-equilibrium condition was clarified by TDMS, TG and FT-IR analyses for the products replaced by LiD or LiND2 for LiH or LiNH2,respectively. The results suggested that H-desorption reaction progresses through two-step elementary reactions mediated by ammonia. As a next step, we carefully determined the amount of the ammonia containing in desorbed hydrogen for the Li-N-H system in a closed system from the practical point of view. The results indicated that a quite small of ammonia thermodynamically coexisted in the desorbed hydrogen in closed system, although ammonia could not be almost detected in emitted hydrogen gas by TDMS under some non-equilibrium conditions. Moreover, for understanding the role of titanium, the chemical bonding state of the titanium compounds doped as catalyst in the mixture was examined by XAFS measurement. The results indicate that the Ti atoms, which can induce catalytic effect, are in a particular chemical bonding state.

Jan 1, 2006

By Tobias Pröll, Bernhard Kronberger, Joachim Rohovec, Werner Hölt, Hermann Hofbauer

"As this is only a first draft, more precise explanations as well as detailed schemes, figures and plots will be included in the final draft. The description og the 100 kW test rig will also be mor detailed as construction is ongoing and will be finished during the summer. Furthermore simulations are to be finished shortly; so details on combustibles and gas concentrations will also be included in the final draft.AbstractOxyFuel combustion is a key technology for the efficient separation of CO2 from fuel combus¬tion (especially coal). Since coal plays a minor role in the Austrian energy mix the application of OxyFuel towards other fuels (biomass, waste fuels) is interesting to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alter¬native fuels is also interesting from a strategic point of view in order to generate knowledge for operation of capture ready cofiring and waste/sludge-incineration plants. OxyFuel uses a synthetic mixture of 02 and recycled exhaust gas where the 02 content may vary. This supplementary degree of freedom allows improved operation especially for low calorific fuels. Heavy fuel oil addition for low calorific combustibles can be omitted when using OxyFuel combustion. Application of alternative fuels (wood, waste wood, municipal waste, sewage sludge) in a 100-kW CFB plant is investigated in combination with process simulation.IntroductionOxyFuel combustion is discussed as one of the key technologies for the efficient separation of CO2 from combustion of fossil fuels (especially coal). Since coal plays only a minor role as primary energy source in Austria, the broadening of the scope towards OxyFuel of other fuels like biomass or waste fuels is necessary to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alternative fuels besides the large coal-oriented projects is interesting also from the strategic point of view. The presented project aims at the generation of knowledge in order to design and operate capture ready cofiring and waste/sludge incineration plants."

Jan 1, 2008

By Terence Makanyire, Animesh Jha

The dissolution and chemical properties of vanadium, zirconium, and niobium in rutile lattice are analyzed by comparing the octahedral site preference energies, with respect to Ti4+ ion in the solvent phase. The oxides are often present in rutile lattice and interfere in achieving the quality of pigment grade TiO2 due to favourable Gibbs energy for dissolution in the solvent rutile matrix. Binary mixtures of V2O5 { TiO2; Nb2O5 { TiO2 and ZrO2 { TiO2 with compositions of 80, 85, 90, 95 and 97 wt% TiO2 were made, pelletized and sintered at 1100 °C for 24 hours. The solidsolution mixtures were then cooled and leached in 2M NaOH for 3 hours at 60 °C. Phase and lattice parameter characterizations, and microstructural and compositional analyses were then carried out using X-ray diraction and SEM/EDX, respectively. The leachates were analysed by Atomic Absorption Spectroscopy (AAS), using which the solute dissolution model for oxides were investigated.

Jan 1, 2014