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By Gjergj Dodbiba, Toyohisa Fujita, Takahiro Kikuchi, I-Chen Wu

"In order to separate molybdenum (Mo) from the high-level radioactive liquid waste (HLLW), Pb-Fe based adsorbents were synthesized. The adsorbents were precipitated by adding sodium hydroxide in mixture of 1 mol/L lead nitrate and 1 mol/L ferric nitrate aqueous solutions. Each precipitate was then filtered, dried and ground to obtain a fine powder, which has been used as an adsorbent. Two main parameters were considered when synthesizing the adsorbents, i.e. the pH value at precipitation of adsorbent precursor and the calcination temperature of Pb-Fe based adsorbent. Moreover, the structures of the synthesized adsorbents were investigated by means of an X-ray diffractometer.The experimental results indicated that the calcination temperature of the Pb-Fe based adsorbent has a great influence on adsorption capacity of the adsorbent for Mo. It was found that when the Pb-Fe based adsorbent was calcinated at 500 oC, the sorbed concentration of Mo was the highest.1. IntroductionThe high-level radioactive liquid waste (HLLW), arising from the reprocessing of nuclear fuel are generally immobilized in an alkali borosilicate glass matrix. Broadly speaking, alkali borosilicate glasses are the matrix of choice for the immobilization of the HLLW, since they permit vitrification of waste stream of variable composition, [1]. Within this frame, the incorporation of molybdenum (Mo) is of particular interest in the vitrification of HLLW. Molybdenum is know to have a low solubility in borosilicate glass compositions and its presence in excess results in the phase separation of a complex yellow molten salt during vitrification, [1]. The formation of so-called “yellow phase” material during the vitrification process is undesirable since it leads to the accelerated corrosion of the inconel crucible liners. Furthermore, the “yellow phase”, which is reported to contain also other fission products, is soluble in aqueous solution providing a potential route for the leaching of radionuclides from the vitrified waste, should it come into contact with water, [1]."

Jan 1, 2008

By Kalyani Das Sarkar

"Steel Authority of India Limited, a Public Sector Undertaking with a production capacity of 14 million tones of crude steel, is India's largest steel maker and ranks among the leading steel producers in the world. SAIL owns and operates eight manufacturing plant – five integrated steel plants at Bhilai, Durgapur, Rourkela, Bokaro and Burnpur producing carbon steel, and three speciality steel plants. All integrated steel plants have hospitals of 650 – 750 bed capacity with modern facilities to serve it's employees and adjoining localities in a clean and sustainable environment.According to the Bio-Medical Waste(Management and Handling) Rules, 1998 and as amended to date, all Bio-Medical waste which is generated during the diagnosis, treatment or immunization of human beings or in research activities pertaining thereto or in the production or testing of biologicals are to be categorized and taken to any facility wherein treatment, disposal of this waste or processes incidental to such treatment or disposal is carried out.The hospital management has created adequate treatment facility for Sharp and Infectious Waste, Pathological Waste and Anatomical Waste through Autoclave, Shredding Machine and developing deep burial pits. Some of these hospitals is ISO 9000-14000 certified. Use of above said treatment facilities in these hospitals are discussed in this paper.INTRODUCTIONBio-Medical waste means any waste, which is generated during diagnosis, treatment or immunization of human beings or animals or in research activities pertaining to these or in the production or testing of biologicals.Steel Authority of India Limited, a Public Sector Undertaking with a production capacity of 14 million tones of crude steel, is India's largest steel maker and ranks among the leading steel producers in the world. SAIL owns and operates eight manufacturing plant – five integrated steel plants at Bhilai, Durgapur, Rourkela, Bokaro and Burnpur producing carbon steel, and three speciality steel plants. All integrated steel plants have hospitals of 650 – 750 bed capacity with modern facilities to serve it's employees and adjoining localities in a clean and sustainable environment."

Jan 1, 2008

By Georgeta Rata, Cornelia Petroman, Ioan Petroman

"Proper training and education in the field of recycling and waste treatment are inconceivable without the proper teaching of the terminology specific to both recycling (aerospace products recycling, automotive recycling, general recycling, recycling behaviour, recycling schemes, recycling systems, and waste recycling) and waste (characterization of waste, electronic waste, heavy-metal containing waste, monitoring of waste, radioactive waste, solid waste, waste collection, waste conversion, waste recycling, waste reutilization, waste stabilization, waste storage, and waste treatment) in both the students’ mother tongue and in English for Special Purposes (ESP) as a second language (with focus on the structuring of the specific terminology). Including linguistic approaches among the possible approaches of environmental protection and material sustainability means including linguistics among the various disciplines addressing energy supply, cement and building materials, metallurgy, chemistry, glassware, pulp and paper industry, machinery, automobile and electronic industries, collection, and sorting, further treatment and final disposal of post-consumer material.IntroductionCultural and technical changes have produced more novel artefacts than novel activities or novel properties, generating new vocabulary needs that are readily answered by new words (nouns).The purpose of this research is to show that ‘waste words’ – phrasal words (items that have the internal structure of phrases but function syntactically as words, e.g., cattle waste) and particularly compound nouns (words formed by combining roots, that tend to have a meaning that is more or less idiosyncratic or unpredictable, e.g., wastepaper ‘discarded paper’) – used in the study of the English of recycling, waste treatment, and clean technologies can be misleading for both native and non-native students and/or users of English because their structure alone does not allow instant, proper understanding of their meaning.Our hypothesis is that this inconvenient can be overcome by getting to reach the proper meaning of these new words. Or, arriving at the precise meanings of the ‘waste words’ depends on our knowledge of the world (for example, wastepaper indicates that some used paper is discarded and not wasted) rather than on purely linguistic knowledge."

Jan 1, 2008

By Norberto Benitez, Christian Ludwig, Simona Regenspurg, Fabian Mendez

"Navarro is the main garbage dump in the city of Cali (Colombia). Operated since the late 1960s it collects about 1.600 tons of waste daily. The environment surrounding Navarro is highly contaminated and the pollutants released by the dump threaten human health in the adjoining neighborhoods. The goal of our project is to identify major pollutants released from the dump and their distribution in the surrounding ecosystem. In a first phase of the sampling and analysis program landfill leachate was collected and screened for heavy metals and for the most common persistent organic pollutants. This allowed us to identify the most relevant compounds on which we focused in a more detailed second phase investigation. These compounds were quantified in the vicinity of the landfill (groundwater, surface water, drinking water and soil) to get information on their mobility and possible pathways into the human body.IntroductionThe usual technique of waste disposal in most developing countries is by landfilling on not -, or not well controlled sites, where people live close by or even on the waste itself. A typical example for this practice is Navarro, the main garbage dump in the city of Cali (Colombia). Operated since the late 1960s it now consists of about 23 million tons of household and industrial waste. The dump is located on a wetland in the riverbed of the Cauca River, the main drinking water source for Cali. Two ponds of unknown permeability located next to the landfill collect a fraction of the waste leachate. During the rainy season, the ponds frequently overflow and drain into the soil (alluvial, loamy sediments) of surrounding sugar cane fields. The environment of Navarro is assumed to be highly polluted and there is evidence that it affects the health of nearby inhabitants. Specifically, the incidence of respiratory diseases was higher among vulnerable individuals (<3 and >50 years old) living in a <3 km perimeter of Navarro as compared with a control group (Solano et al., 2006). Further, a clustering of extremely rare congenital malformations (sirenomelias and cyclops) was observed in a small area during a short time period (<6 months) (Filigrana et al., 2008)."

Jan 1, 2008

By T. Takasu

Overall productivity in copper refining is currently determined by the electrorefining process. Previous research showed that forced convection of the electrolyte improves the morphology of the copper deposit on the cathode and suppresses passivation of the anode. In this paper, electrorefining experiments under forced convection were carried out in the presence of As, Sb and Bi impurities, both in electrolyte and in the anode, to determine the effect of the impurities on the electrorefining process. The concentrations of the impurities in the deposit increased with increasing current density without forced convection. An increase in the fluid velocity suppressed the increase in impurity concentration. These concentrations were high, especially in the initial stage of deposition without forced convection, corresponding to a decrease in the cathode potential measured during that period. This indicates that the enrichment of impurities was induced electrochemically. The reason for the decrease in cathode potential was the low concentration of copper ions on the electrode surface because of ion consumption by the electrolysis. The forced convection of the electrolyte enhanced the ionic mass transfer and thus suppressed the polarization and deposition of the impurities. The fluid motion was shown to be effective in achieving electrolysis under high current density conditions.

Jan 1, 1999

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

By Kaixi Jiang, Bangsheng Zhang, Lei Zhang, Haibei Wang, Xiaoping Zou

"China plays an important role in the global molybdenum industry; in fact, both China's molybdenum mine and smelter production ranked first in the world. The characteristics of China's molybdenum resources are quite complex, and moly-nickel ores with carbon, coppermoly ores and wulfenite can be only found in China. This paper firstly introduces China's molybdenum resource/ reserve situation. Secondly, the status of molybdenum smelting technologies, especially roasting by rotary kilns and multiple-hearth furnaces, are discussed. The practices and the development of some new technologies, such as pressure leaching, solvent extraction, ion exchange, carbon adsorption for moly-nickel ores and low grade molybdenite concentrates, are also introduced.IntroductionMolybdenum is widely used in special steels, aviation, alloys, chemistry, electronic and medical industries because of its excellent physical and chemical characters [1,2].In nature, molybdenum exists mainly as molybdenite associated with copper ore which are the main material for smelting. About 99% of molybdenum is produced from molybdenite. In addition, wulfenite, molybdenum oxide ore and graphite shale containing Mo-Ni have also industrial value to extract molybdenum and other metals such as Ni, Re, Pb and Zn. The reserves of molybdenum in China are about 8.4 million tons metal; China is ranked as the second largest source in the world. The output in China is more than 40 kt in 2010. Ferromolybdenum is the main product and then ammonium molybdate. The consumption in China is about 20 kt and the rest is exported to overseas.The first molybdenum smelter in China was built in 1963. Today the main producers include Jinduicheng Moly Company, Luanchuan Moly Company and Jiangxi Copper Group Company. Technologies and equipment have changed greatly. Roasting and multi-hearth furnaces are widely used. Several new processes were developed such as pressure leaching, solvent extraction, ion exchange and carbon absorption [3-8]."

Jan 1, 2012

By Line Hallgren

The fluid flow in the mold during up-hill teeming is of great importance for the quality of the cast ingot and therefore the quality of the final steel products. At the early stage of the filling of an up-hill teeming mold, steel enters, with high velocity, through the nozzle into the mold and the turbulence on the meniscus could lead to entrainment of mold flux. The entrained mold flux might subsequently end up as defects in the final product. It is therefore very important to get a mild and stable inlet flow in the entrance region of the mold. It has been acknowledged recently that swirling motion induced using a twist tape swirl blade, in the submerged entry nozzle is remarkably effective to control the fluid flow pattern in both the slab and billet type continuous casting molds, resulting in increased productivity and quality of the produced steel. From the above result, we propose, swirling flow generated through a swirl blade inserted into the entry nozzle, as a new method of reducing the deformation of the rising surface and the unevenness of the flow during filling of the up-hill teeming mold. The swirling blade has two features: (1) to generate a swirling flow in the entrance nozzle and (2) to suppress the uneven flow, generated/developed after flowing through the elbow. The effect of the use of a twist tape swirl blade was studied using both numerical calculations and physical modeling. Water modeling was used to assert the effect of the swirling blade on rectifying of tangential and axial velocities in the filling tube for the up-hill teeming and also to verify the results from the numerical calculations.

Jan 1, 2006

By Nicola Baldo, Marco Pasetto

"The paper presents the results of a laboratory study, conducted at the Experimental Road Laboratory of the University of Padova, in order to verify the possibility to use different types of electric arc furnace (EAF) steel slags – in substitution of the natural aggregates – in the composition of both dense graded and porous asphalt mixes for flexible road pavements. The research has been articulated in a preliminary study of the chemical, physical, and mechanical properties of the EAF steel slags, and in the following mix design and performance characterization of the bituminous concretes, through stiffness modulus tests at various temperatures and permanent deformation (creep) tests. All the mixtures with EAF slags have satisfied the requisites for acceptance standardized for the road sector, thus resulting as suitable for use in the construction of infrastructures, moreover presenting higher mechanical characteristics than those of the corresponding asphalts with full natural aggregate. IntroductionSteel is produced industrially employing two main technologies: the integral cycle, which starts from mineral iron, and the electric cycle, which uses scrap metal. A consistent amount of the steel produced in Italy (approx. 55%) comes from Electric Arc Furnaces (EAF), which every year, alongside the steel, produce approximately 2 million tons of slag. The recycling of this waste product to produce new high-quality raw materials would reduce both the exploitation of limited natural resources and the amounts of refuse. In the European Union, 60% of slag from EAF is still today disposed of in dumps. The extremely diverse origins of scrap metal (waste from mechanical manufacturing, industrial and civil demolition, car bodywork, etc.) means that the by-products generated by the smelting, slags and ashes, contain different elements, in varying composition, also depending on the type of steel to be produced and the consequent adding of binding and melting elements during the production process. For this reason, iron and steel industry electric furnace slag - unlike the blast furnace dross utilised in cement works, which has a more uniform composition as it comes from a more standardised cycle – has been viewed in the past with some diffidence and so, at least in Italy, the possibilities of its re-use have never been fully developed."

Jan 1, 2008

By Felipe P. D. Lopes, Ailton Silva Ferreira, Sergio N. Monteiro

"Environmental issues such as global warming and water pollution are motivating fast changes in scientific and technological paradigms. Special importance is now being given to the so called environmentally friendly materials, which are renewable, recyclable and biodegradable. An example is the natural fibers with increasing industrial applications beyond the conventional uses as baskets, fabrics, ropes and carpets. In addition to traditional natural fibers, others like curaua (Ananas erectifolius) are being investigated for possible use as reinforcement of industrial composites. Since epoxy matrix is not yet incorporated with curaua fibers, the objective of this paper was to study the basic properties of epoxy composites reinforced with different amounts of curaua waste fibers. A comparative analysis aiming at the use of these composites as substitute for conventional building materials was carried out.IntroductionThis new millennium, which initiates with the 21th century, is experiencing a fast degradation of the environment by pollution and climate changes. Most of the problems are related to our methods of development associated with the use of fossil fuels and the energy intensive processing and production of synthetic materials. As a consequence, environmental issues such as global warming and ocean pollution are motivating rapid changes in technological paradigms. One relevant example is the current importance given to natural materials like the lignocellulosic fibers extracted from cultivated plants or found as industrial wastes [1]. These fibers are considered environmentally correct alternatives to substitute energy intensive conventional synthetic fibers such as carbon, glass, nylon and aramid. In addition to the renewable recyclable and biodegradable nature of the lignocellulosic fibers, the low cost and abundance in developing regions are major advantages that justify their increasing application as reinforcement of composites [2,3].In fact, nowadays, the use of natural fibers is no longer restricted to baskets, ropes, clothes and carpets. Industrial composites are introducing these fibers in large technological segments associated with car making, building construction and furniture [4,5]."

Jan 1, 2008

By A. A. Bustos

Four Air Liquide Shrouded Injectors (ALSI ) were installed and operated for over one year in a Peirce-Smith converter at the Falconbridge nickel smelter in Falconbridge, Ontario, Canada. A shrouded injector consists of an inner pipe and an annulus, through which high oxygen enriched air and nitrogen flow, respectively The nitrogen cools the injector and protects the refractory in the vicinity of the injector tip, allowing for substantial increases in oxygen flow rates to the converting reactions. Several injector designs were tested to study the effect of changes in the cross-sectional area and changes in the entrance geometry of the annulus. An optimum design would minimize the injection pressure required for a given flow rate to achieve choked flow conditions at the tip of the injector. The operation of the ALSI was simple and did not require any special care or maintenance, either between blows or between converter cycles. In particular, the shrouded injectors did not require punching, as is the case with conventional tuyeres. In terms of refractory performance, the ALSI, operating at 30-40 % oxygen enrichment, were superior or equal to the conventional tuyeres, which operated at 21-23% oxygen. The results of the demonstration program led Falconbridge Limited to implement the ALSI technology on a commercial scale The paper presents the demonstration program results in terms of gas flow rates, accretion formation, punchless operation and refractory wear.

Jan 1, 1999

By P. S. Arthur

The ISASMELT? process is a submerged lance smelting technology operating in smelters in Australia, the USA, Belgium, India, Germany, Malaysia and China. Further plants are under construction in Peru and Zambia. Following the invention of the Sirosmelt lance technology Mount Isa Mines recognised the commercial potential in the novel top blown bath smelting process and embarked on a development program that has lasted more than 25 years. After successful operation of pilot plants and demonstration plants producing copper and lead, Mount Isa Mines decided to license the technology to external companies. Since the purchase of Mount Isa Mines by Xstrata in 2003, Xstrata Technology has assumed responsibility for transferring the technology to ISASMELT? licensees. In the 15 years since the first commercial furnaces started operation plants have been constructed (or are under construction) with a combined annual smelting capacity of more than six million tonnes of concentrates or secondary raw materials. Process development continues on the commercial scale plants at Mount Isa and elsewhere. Many of the improvements implemented by plant operators have been passed on to, and adopted by, other licensees. Exchange of ideas and technical improvements occurs through ad hoc visits to fellow licensee sites and through regular licensee workshops arranged by Xstrata Technology. This paper updates the reader on the status of various ISASMELT? plants either operating or under construction. It highlights the important role that the technology provider?s operational experience plays in ensuring that new smelting plants ramp up quickly to nameplate capacity.

Jan 1, 2006

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

By Kurt Svens

"As zinc consumption is gradually increasing all the time in the world, many zinc plants are looking for possible expansions. As the sulphuric acid market as well as the fertilizer market in many areas is saturated, the costs for the roasting-acid plant section of the zinc plant will create problems when making feasibility calculations for possible expansions. For solving the customers' situation, two proven zinc concentrate direct leaching technologies are available. A third one, which is possible, does not have any industrially proven applications in the zinc area.IntroductionTime to time, the zinc plants in the world scrutinize their operations with respect to their cost efficiency, the total zinc recovery and the near-by or far-away consumer markets, especially the for zinc and sulphuric acid. Their preliminary profitability calculations can show that a possible total expansion is not economical, when they are looking to expand the whole roasting/acid plant - leaching - solution purification - electrowinning - casting route, as the possible market price for the sulphuric acid is low or the sulphuric acid market is too far away. Based on these facts, their economical study often indicates that implementing a zinc concentrate direct leaching option could be more favourable. Regarding this situation, several aspects concerning three alternative direct leaching methods will be discussed, of which pressure leaching and the atmospheric leaching processes have several industrial applications in the zinc industry, as the ultrafine grinding - conventional leaching process at present has none. As iron is also dissolved during zinc concentrate direct leaching, iron removal processes generally used in the zinc industry are additionally discussed below."

Jan 1, 2012

By Samson Adeosun, Sanmbo Balogun, David Esezobor

"In a typical year, approximately 1.7 million tons of residues and wastes are expected from Ajaokuta integrated steel plant, Nigeria. They will be generated mainly from sinter plant, blast furnace (BF), and basic oxygen furnace (BOF) operations and during rolling and finishing. The residues and wastes include slag, dust, sludge and slurries from gas cleaning, waste water, mill scales and other associated scraps. In this paper concepts for the utilization of residues and wastes in Ajaokuta Steel Plant where no reclamation routines have been provided for in the first and second phases of its project implementation is designed. The paper analyses the sources of the iron oxide wastes and evaluates the quantities expected from the main production facilities of the plant which include the two 312 m2 capacity sintering machines, the two 2000 m3 blast furnaces and two 130-T BOF (of the 2nd phase expansion of the Steel Plant). A reclamation routine designed for Ajaokuta residues and wastes is presented.IntroductionIn the steel industry, approximately 550kg of residues per ton of crude steel arise from the production processes and from pollution control facilities [1- 4]. These residues consist of slag, dusts and sludge, mill scale, spent pickle liquor, and other iron bearing materials. The main by – products generated in the steel industry are listed in Table I.Although major progress has been made in the recycling and use of some of these residues, particularly flue dust, blast furnace and steel making slag, yet a significant quantity are land filled or stockpiled. These unsightly stockpiles occupy valuable real estate and may become a source of environmental pollution if not otherwise disposed. In any case, the dumping option has become quite costly. For instance, one ton of iron ore costs between 28 and 34 US dollar, whereas as much as $20 per ton of steel produced is required to meet environmental compliance obligation in the USA [5, 6]."

Jan 1, 2008

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

By Bora Derin, Adnan Aydin, Onuralp Yucel, Hakan Morcali

"The steelmaking industry which uses electric arc furnaces (EAF) generates approximately 250.000 tons of EAF flue dusts annually in Turkey. These flue dusts contain valuable metals such as zinc, iron and lead. For example, if these flue dusts can be treated efficiently, disposal problems certainly decreases and annually almost 40.000-75.000 tons of zinc can be recovered. In this study, powder and pellet forms of EAF flue dusts taken from a steel mill were carbothermally treated in a temperature controlled pilot scale rotary furnace via carbothermal reduction in order to investigate the reduction behavior of Zn and Pb. Temperature (900-1000 and 1100 °C) and time (0-90 minutes) were selected as reaction parameters. The chemical analysis was performed for the sample residues.IntroductionTurkey’s steel production reached to 23.3 million tons in 2006. There are three integrated steel plants of which capacities vary from 0.7 to 3 million tons per year and seventeen EAF steel plants of which capacities vary from 0.06 to 2 million tons per year [1]. When it is considered that more than 74 % of the Turkish steel production is produced by EAF method and approximately 10 - 15 kg of dust is formed per ton of steel during this process, the amount of annual generated EAF dust may be estimated at approximately 0.25 million tons. EAF dust which contains valuable metals such as zinc, lead, iron, cadmium, and chromium, is considered as hazardous waste product in steelmaking industry. If these flue dusts can be treated efficiently, not only the disposal problems certainly decrease, but also annually almost 40.000-75.000 tons of zinc can be recovered. Many studies which exist on recovering of the valuable metals from EAF dust, propose and practice many hydro-metallurgical and pyro-metallurgical treatments [2- 7]. In this study a laboratory scale work were performed to investigate reduction behavior of zinc and lead in EAF dust by carbothermal process in a rotary furnace."

Jan 1, 2008

By Xiping Chen, Wangxing Li, Jiemi Zhou

"Desulfurization methods suitable for anode-grade petroleum coke (coke for short) used in primary aluminum industry are coke desulfurization during calcination, desulfurization in soakage and desulfurization in mediums. Coke desulfurization during calcination is discussed in this paper. Influences of calcination temperature, holding time and coke granularity on coke desulfurization were discussed. Experimental results show that calcination temperature has a remarkable influence on coke desulfurization. When the temperature is high enough desulfurization ratio of coke can reach 85% only by calcination. Holding time has a definite influence on coke desulfurization, but desulfurization ratio is low at the temperature of 900~1300°C. The influence of holding time is obvious when calcination temperature surpasses 1400°C. The influence of coke granularity is smaller compared with calcination temperature and holding time.IntroductionPetroleum coke is main raw material for carbon anode in primary aluminum industry, and its weight percentage in carbon anode is about seven percent. Green coke can not be directly used for anode production because of its immanent moisture and volatiles. Green coke must be calcined in order to meet the request of anode production. Calcination is a heat-treatment process during which green coke is heated to a given temperature to remove volatiles, moisture and some sulfur. Real density, strength, electrical conductivity and anti-oxidation ability of petroleum coke can be improved by calcination and calcined coke can be received [1, 3, 4]. Sulfur in calcined coke finally goes into carbon anode. During baking or aluminum smelting, the sulfur in anode ultimately changes into SO2 and emits from anode into the atmosphere. Excess SO2 easily leads to acid rain which brings heavy pollution to the environment [1, 2]. With the development of Chinese aluminum industry, consumption of anode-grade petroleum coke increases year by year, the total consumption in 2007 surpassed 4.5 million tones and the yearly emission of SO2 from aluminum smelters has exceeded 270 kilotones. From 2005 Chinese government began to limit the emission of SO2 from primary aluminum industry, so desulfurization of anode-grade petroleum coke becomes more and more urgent. Some relationship need to be found and used to guide desulfurization of petroleum coke."

Jan 1, 2008

By Bekir Karasu

Boron raw materials are amongst the most important natural sources for many industrial branches and their values become increasingly raised with the discovery of boron usage in many new technological fields. All the countries in the world are unfortunately not as lucky as Turkiye and USA where major boron deposits are mainly located. It is widely known fact that on one side, boron is very precious component with its technological importance, on the other; only its limited sources are available. Therefore, even its wastes have to be evaluated and regained. In the present work wastes of Etibor Kirka Borax Company of Turkiye were used in the production of opaque frits which was suitable for floor tile glazes. Standard and newly produced frit based glazes were applied on the pre-engobed floor tile bodies and single firing was employed. Final products were examined according to the certain standard tests and their microstructures were also investigated. All the results confirmed the evaluation of boron wastes in opaque floor tile glazes.

Jan 1, 2006

By Luis Velazquez, Andrea Zavala, Nora Munguia

"This paper is aimed at describing the evolutive strategy in which the University of Sonora is following for optimizing the organic and inorganic material life cycle in the products used on campus. The institutional strategy has be oriented towards new patterns of behaviors in order to integrate the principles of sustainability as a guideline for preventing, eliminating, and/or reducing the negative environmental and occupational impacts generated when performing university substantive functions of teaching, research, and outreaching and partnership as well as its management operation tasks.IntroductionThe University of Sonora is the largest and most important university among several other universities in both the city and the state. It is a public university with a 29,792 students in three campuses in the state. The main campus of the University of Sonora is located in the capital city of Hermosillo, which has a population of more than 609,829, in the state of Sonora in the northwestern region of Mexico [1].Despite the fact that in the University of Sonora there were, in the eighties, some projects dealing with environmental issues, there was not until 1992 that the sustainability efforts were really initiated. It happened when the Sustainable Development Group was created in the Department of Industrial and Systems Engineering as a response to the need for adapting the industrial engineering curricula to the challenge of sustainable development [2]. In order to promote sustainability, it has been necessary to cope and break with several university paradigms. For this reason, the strategy for becoming a sustainable university has continuously evolved throughout the years from a simple structure composed by individual and isolated projects to a systematic and integrative Sustainability Management System. Thanks to this evolution, the University of Sonora has won a respectable reputation in the greater community and it is seen in the region as an icon of sustainability promoter. In this sense, the substantives functions of education, research, and outreach and partnership, which are considered supportive and integrative, have also evolved to play a key role for the success of sustainability initiatives.The institution has followed four avenues for becoming a sustainable university; education, research, outreaching and partnership and greening the campus [3]."

Jan 1, 2008