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By Juha Järvi

Outokumpu Zinc Oy has two separate roasting lines with fluidized bed furnaces and waste heat boilers for calcine collection and heat recovery. During the last 30 years, zinc production in Kokkola plant has increased continuously and at the same time the raw materials have changed. Therefore, the waste heat boiler has been under continuous research and development. The waste heat boiler plays a significant role in the process and consequently the reliability and efficiency of the device is important for the effectiveness of the entire process. Many changes have been made to the boiler in the last decades. New radiation tube screens, tube bundles, and baffle-plate constructions have been added to the boiler and also rapping systems for the dust have been developed. The latest improvement to the boilers was a baffle wall, located in the middle of the radiation section roof in the first boiler, and baffle plates in the lower part of the convection section in the second boiler. The new boiler design and optimization were carried out using physical water and air-dust modeling as well as computational fluid dynamics. The modeling work agrees well with experiences in practice. The latest developments have increased the operating hours per year and the effectiveness of the waste heat boiler.

Jan 1, 2002

By Nicola Baldo, Marco Pasetto

"The paper discusses the results of a laboratory study, aimed to evaluate the suitability of the bottom ash from Municipal Solid Waste Incineration (MSWI), obtained from different Italian plants, to be recycled in the lithic skeleton of bituminous mixtures, for base layers of road and airport pavements. The research involved a preliminary study of the physical and geotechnical properties of the bottom ash by itself; it was followed by a mechanical characterization of the bituminous concretes. The traditional Marshall methodology was used to identify the optimum bitumen content; the mixtures were also mechanically checked by means of the stiffness modulus test, repeated load axial test and fatigue test. Because the requisites for acceptance in the Italian Specifications and Standards have been satisfied and given the positive mechanical performances, it has been verified that the MSWI bottom ash can be used as substitution of the lithic materials in the road bases, also with very high contents (up to 81% on the weight of the aggregate). Introduction The incineration of Municipal Solid Wastes (MSWs) provides for by-products which can be mainly classified as bottom ash and fly ash. The first one, corresponding to the 25% on the weight of the wastes to be incinerated, so resulting the principal product of the process, is mainly composed by Silica (Si), Iron (Fe), Calcium (Ca), Aluminium (Al), Sodium (Na) and Potassium (K) oxides, so presenting a composition similar to that of different natural materials. Its metallic fraction can be recovered; the remaining part is usually stocked in dumping or, less frequently, recycled. Bottom ash can be re-utilised in the construction of new infrastructures, especially in bitumen bounded mixtures, because of the inert properties of the binder which covers the grains with a subtle film, that prevents the release of heavy metals. The paper describes a study aimed to design new bituminous mixes for flexible road and airport pavements, realised with the highest content of 4 types of bottom ashes, deriving from different MSWI plants of the Northern Italy. The ashes will be named as BA1, BA2, BA3, BA4 respectively (the origin cannot be specified)."

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/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 Aly M. Abdel-Rehim

The present work deals with a study of the mechanical activation of processing of Egyptian monazite by its simultaneous ball-milling and pressure leaching in order to improve the recovery of thorium and lanthanides from monazite. Experiments of simultaneous ball-milling and alkaline leaching of monazite contrary to autoclave leaching were carried out in stainless steel ball-mills of cylindrical shape under different conditions of temperature, pressure, time and alkali amount and strength. The ball-mills were heated and mechanically rotated in an electric furnace by means of roll mechanism. The effective rotation speed was fixed at 130 rpm in all tests. The charge of steel balls of different diameters was equivalent to 45% of the total mill volume. Monazite was charged in ball-mill without preliminary grinding. It is found that high rate of monazite leaching by ball-milling leaching method is achieved at lower temperature, shorter time and lower expense of alkali than in autoclaves. The results obtained show that complete recovery of thorium and lanthanides from monazite (99.8%) by simultaneous ball milling and alkaline leaching is attained at 140°C within 2 h. It is concluded that processing of monazite by its simultaneous ball-milling and leaching is mechanically activated and accelerated as a result of grinding action of steel balls that caused the continuous removal of the hydroxide product from reacting particle surfaces. This leads to the exposing of fresh and activated monazite particles surfaces to alkali leach solution and consequently the acceleration of the reaction of monazite processing.

Jan 1, 2006

By Alireza Zakeri

To evaluate the behavior of minor elements in the copper smelting process, activities of silver, selenium and tellurium at minor concentration were determined at 1473 K within the miscibility gap of the Cu-S-Me (Me = Ag, Se, Te) and Cu-Fe-S-Me systems varied in Fe/Cu ratio. Phase relations between the immiscible metal and matte phases in the foregoing systems were first established by a quenching technique at 1473 K to supplement the activity measurement data. A Knudsen-effusion mass spectrometer, capable of handling complex gaseous systems and relatively small vapor pressures, was adopted for activity determination. Using a multiple Knudsen-cell, the ion intensity of minor element in the sample under study was measured simultaneously with that in a reference sample. Activity was obtained from the ratio between the measured ion intensities as well as the known activity value of the minor element in the reference sample. Limiting activity coefficients of the minor elements were correlated with composition of the matte. Based on the experimental results, the vaporization behavior of the minor elements has been discussed.

Jan 1, 1999

By J. Partinen

Drying is a unit process which has numerous applications in metallurgical process industry. Kumera Technology Center, being a worldwide equipment and process supplier, has developed sophisticated solutions for both direct and indirect drying. In conventional direct drum drying, the energy is taken from combustion of fossil fuels, requiring energy input and emitting considerable amount of off gases. In modem copper smelters, thermal energy from the off gases is recovered in waste heat boilers making the steam available. Using that steam as the energy source for concentrate drying, the total volume of off gases can be considerably reduced and releasing of harmful combustion gases into the atmosphere can be avoided. Kumera Technology Center has recently developed and promotes a new steam drying process for drying of copper concentrates. In the development of the new dryer, Kumera's approach has been to combine the best properties of both the steam dryers and the drum dryers. In the design special attention has been paid to overcome problems of excessive wear and clogging and to reduce the required maintenance operations. In this paper the environmental issues and energy consumption related to both direct and indirect drying processes are discussed. The estimated operation costs and emission levels are compared, based on calculations and the data collected from industry. Finally, the development project of the Kumera Steam Dryer is briefly reviewed

Jan 1, 1999

By A. Kapilashrami

Slag foaming proves to be both blessing and curse for the process productivity, depending on where in the process it occurs. In pyrometallurgical processes, slag foaming is often a result of chemical reactions taking place in the slag. As the slag composition and reaction rates are changing, foaming occurs under dynamic conditions. In the present work, slag foaming was studied with XRF. The foam displayed a fluctuating behaviour, unaccountable by existing models. The concept of foaming index was found not to be satisfactory in describing the foam, resulting in the need for alternative theories. The rate of fluctuations was seen to be related to the difference between rate of gas generation and rate of gas escape from the system (Ug-Ue) as well as the bubble sizes. Thus, model development of dynamic foaming phenomenon has to take the effective chemical reaction rate as well as the bubble sizes into consideration. The first step in obtaining foam is to form bubbles. In the present work, gas bubbles were generated through chemical reaction at interface between two immiscible liquids and the bubble formation was studied optically. The gas bubble size was seen to be uninfluenced by the reaction rate. However, bubble formation was seen to take place in one of the phases and since the bubbles consequently traversed the interface under the influence of buoyancy, the viscosity of the first phase was found to influence the final bubble size where increased viscosity would yield a larger bubble size.

Jan 1, 2006

By Emilia Visileanu, Eftalea Carpus

"The strategy of developing the Romanian textile industry sub-sectors envisages the achieving of certain superior production indices, from a physical and value point of view, in 2010, a quantitative increase of textile wastes by 14% in 2010 as compared to 2000, implicitly. The percentage of the turned-to-profit wastes will have an increasing tendency, from 53.6% in 2000 to 74.7% in 2010. The article synthetically presents the innovative elements of the technology of processing the industry textile wastes.1. Introduction“People will need to re-adopt this sense of rarity that has been forgotten over the last two centuries. Humans need to collect, sort, recover, going back to the old ideal of alchemists: complete the material cycle, turn waste into resource, reduce all forms of predatory behaviour as much as possible”Irrespective of the historical period, geographical positioning, economic power or employed technologies, wastes resulted and will result in a bigger or smaller quantity as long as life and activity on Earth go on. The negative effects of these over the environment factors and implicitly over population health are well known all over the world and not approaching this matter enough may have catastrophic consequences over life. Having in view these aspects, finding solutions for diminishing the general waste quantity and limiting the negative effects of those products is important, by effecting the reusing of the recyclable ones in the production processes as secondary raw materials, and by ecologically treating and storing those than cannot be reused.2. Experiments and researchesThe textile industry affects the environment by the high water, energy and chemical consumption, as well as by the high quantity of wastes that are the result of using an impressive number of chemical substances and technological processes.The development strategy of the Romanian textile industry sub-sectors foresees, for 2010, the achieving of certain higher production indices as compared to 2000, both in terms of materials (as merchandise) and in terms of value, which implicitly leads to a quantitative increase of wastes.The flexible, economic and ecologic technologies which include systems of waste preliminary preparing (cutting, opening) and conventional or non-conventional system of processing the recovered fibres lay at the basis of substantiating the activity of implementing the notion of zero wastes."

Jan 1, 2008

By Józef Czernecki

The Polish copper concentrates are characterised by low content of sulphur and iron. At KGHM Polska Miedz S.A. two copper production technologies are in use. The shaft furnace process is used at the Legnica Copper Smelter and the Glogów I Copper Smelter. A single-stage direct to blister Outokumpu flash smelting process is used at the- Glogów II Copper Smelter. Melting copper concentrates in the shaft furnaces is carried out in a reducing atmosphere and the product obtained is a matte. Instead, a result of melting copper concentrates by an oxidising flash process blister copper of a quality similar to that of converter copper is obtained. The annual copper production at KGHM Polska Miedz S.A. exceeds 450,000 tons. Another important metal is silver produced from slimes from copper electrolysis (about 1000 t/y). Moreover, such metals as Pb, Ni, Se, As, Au and other precious metals, including Pt and Pd, are recovered from various semiproducts. This paper presents technological flow sheet of the copper production in plants using the shaft furnaces and in another plant in which a single-state flash process is applied. Characteristics of products, methods of their utilisation, main parameters of particular technological operations, and advantages and shortcomings of the solution applied are presented. There are also discussed: the natural environment protection as well as directions of the KGHM Polska Miedz S.A. plants modernisation.

Jan 1, 1999

By D. Quattrini

The aim of the present work is to present the gas chromatography (GC) as an alternative method of analysis in the thermal decomposition of calcium carbonate. Therefore, a furnace/GC on-line system was employed to study the kinetics of the reaction, measuring the CO2 produced in the decomposition. One of the advantages of the GC method is the possibility to perform an in-situ characterization and quantification of the gaseous products to obtain kinetic parameters, besides the method is simple and shows a good reproducibility. The decomposition of calcium carbonate was carried out in isothermal conditions at temperatures from 655 to 715°C with nitrogen as purge gas. Several gas velocities were used to determine the adequate flow that minimizes the effect of external mass diffusion as rate controlling step. It was made a preliminary analysis of the sample size influence on the reaction rate. The activation energy of the reaction was determined by Flynn method. The value obtained was in a good agreement with other authors. On the other hand, gravimetric measurements were employed for compare GC results.

Jan 1, 2006

By Amanda C. Lima, Luiz Augusto H. Terrones, Sergio N. Monteiro

"Fabric from weaved yarns made of jute fibers have been considered as reinforcement for polymeric composites. In particular, these fabrics obtained from discarded sackcloth are presently being investigated as environmentally friendly composites with recycled polyethylene matrix. The objective of the present work was to compare the practical properties and economical aspects of these composites with those of conventional materials such as wooden board and gypsum panels for building application. The comparison showed that, depending on the amount of post-used jute fabric, a cost/benefit analysis favors these composites over the conventional materials.IntroductionThe increasing amount of wastes generated by human activities is becoming a worldwide problem of pollution with growing consequences to the environment. The question on how to dispose these wastes is, therefore, a major global issue. Among the possibilities of it gating the problem, the use of materials with characteristics of being renewable, biodegradable and recyclable is considered an environmentally correct solution. Examples of this type of materials are left over lignocellulosic fiber from coconut husks and sugarcane bagasse [1] that, after the primary extraction of edible pulp and juices, can be recover for industrial application. Nowadays, the main use of these fibers is to reinforce polymeric composites applied as components for building construction and automobile parts [2,3]. In addition to these applications, composites reinforced with residual lignocellulosic fibers may replace conventional furniture and panels made of wood and thus help to reduce deforestation [4].Environmental protection is not the only motivation for recycling natural fiber wastes. In developing regions activities associate with collecting and processing residual fibers provide job opportunities for low-income people. Moreover, if the lignocellulosic fiber is collected as a recyclable waste, it hes the economic advantage of a comparatively cost, which constitutes in a relevant difference as a choice for commercial utilization."

Jan 1, 2008

By Magdelinka Padenkova-Yaneva, Emilia Christova Kostakeva

"One of the methods for waste treatment is composting during which as a result of controlled biological decomposition of organic waste in aerobic conditions harmless materials are received. Composting takes place in suitably designed premises which ensure the optimal conditions for biochemical decomposition of the waste. A usual way to process composting is the spreading of the waste on a base made from reinforced concrete.In the paper the phases and basic technical features of the process of composting, the requirements and properties of the base and the ways of protection of concrete base against corrosion are revealed. Technical decisions for a specific construction site in Bulgaria are shown and the advantage of achieving durability of the concrete constructions in the plant while achieving simultaneous environment protection from pollution is discussed.IntroductionComposting is the process of controlled biochemical decomposition of vegetable and animal organic waste in aerobic conditions as a result of which harmless materials are obtained. The latter have better stability and are rich in humus substances which are useful for agricultural crops and can be used for restoring the soil fertility [1, 2, 3, 4].In modern waste treatment plants a composting technology is adopted in which the waste is spread on a concrete base as piles with certain dimensions [1, 3]. These piles are periodically stirred or air is blown through them in order to ensure the quantity of oxygen required for the process of aerobic decomposition of the organic matter. The fluids and gases formed in the course of the composting are take away in order not to pollute the environment – air, water, and soils. For this purpose the base on which the waste is spread must satisfy certain requirements, and the gases must be taken away and rendered harmless in order to protect the atmospheric air from pollution. This paper discusses the need for protecting the concrete base from corrosion and characterizes the stages and main parameters of the composting process and the possibilities for primary and secondary protection of the concrete base from corrosion. Specific technical decisions applied in a composting facility in the area of the town of Plovdiv are presented."

Jan 1, 2008

By Tracy T. Morris, Luis G. Navaro

"Anodic copper slimes produced during the electrolytic refining of copper are routinely batch leached to remove copper. At the Amarillo Copper Refinery, an atmospheric leaching process was converted to an autoclave pressure leaching system to improve the removal of copper, reduce the consumption of oxygen, improve leaching times and enhance tellurium recovery. The benefits of pressurized versus atmospheric leaching of slimes were soon realized by obtaining the desired level of decopperization in a shorter time and with lesser quantities of reagents. The autoclave was designed and constructed with a unique oxygen injection system that enables good control of the leaching process and with no plug-ups. Other features include a mass measuring system that balances the quantity of slimes to be leached to the desired final solution concentration based on initial feed concentrations. The end result was a more efficient and controllable leaching process for removing copper from anode slimes.IntroductionThe electrolytic refining of copper consists of an electrolytic cell filled with a sulfiiric acid based electrolyte and pairs of copper anodes and cathodes. When a current is applied, copper in the anode dissolves and is plated onto the cathode. Impurities within the anode that are more noble than copper do not dissolve and end up at the bottom of the cell and are referred to as slimes. Gold and silver are the main slimes constituents of interest because of their monetary value, but there typically are significant quantities of selenium, tellurium, lead, antimony, arsenic, bismuth, nickel, silica and tin. Copper is also present, usually as a metallic or as a reactant with tellurium, selenium, oxygen or sulfur and can range from 10 to 30% of the slimes fall."

Jan 1, 2012

By Petr Sulovsky, Pavel Leber, Jaroslava Ledererova, Miroslav Svoboda

"The properties of raw materials used for the production of building materials play an essential role in their choice. Industrial waste materials can in some cases improve the performance of new building materials, when compared with classical raw materials. The addition of waste can however negatively impact some of the building material´s characteristics, influencing its stability, service time, durability, and can introduce undesirable variation of certain characteristics over time. It is necessary that each secondary raw material intended for such use be thoroughly investigated in terms of its chemical, physical, and mechanical properties, with special attention paid to the risk components and risk parameters. It is necessary to make many- sided technological tests in relation to the required characteristics of the resulting materials for each chosen application. Moreover, the limit values for the critical (risk) parameters, which the given secondary raw material must satisfy to be used in a specific technology, need to be defined. Introduction The risk components in the industrial waste materials to be used in the production of building materials fall into two groups: - components that pose a risk of development (instant or delayed) of a process deleterious to the utility properties and durability of the resulting materials. Such processes include volume change (expansion as well as shrinkage), alkali-silica reaction, delayed ettringite formation, thaumassite attack, aggressive carbonation, etc. - elements or components that can, if released from the waste-containing building material, pollute the environment. They involve the so called potentially hazardous elements as well as compounds like fenols, PCB, PAHs etc. From the viewpoint of the presence of both groups of risk components, the wastes can be classified as: • environmentally inert waste materials. They are produced in the largest volumes and do not pose a threat to human health. Their physical and/or chemical characteristics fail to satisfy all requirements for utilization in ordinary production. The aim of technology design is to work them into the building products with suitable utility properties. • easier workable waste materials containing toxic components are produced in large volumes. In spite of the content of toxic components, their physical and chemical properties make them suitable for ordinary production, provided that the harmful substances are immobilized by the chosen technology."

Jan 1, 2008

By Bradford C. Wesstrom, Omar Araujo

"Impurities from an electrolytic refinery are typically extracted from the electrolyte utilizing conventional electrowinning cells. These cells are arranged in series with cascading solution flow and are commonly referred to as liberator cells. The Freeport McMoRan Copper & Gold El Paso Refinery has optimized the removal of arsenic in cascading liberator cells by utilizing two separate feed solutions. The primary feed solution is recycled liberator electrolyte and the secondary feed solution is ""neat"" tank house electrolyte. The secondary feed solution is added based on the voltage response across the individual cells utilizing independent variable frequency drive (VFD) pumps. When the voltage across a cell changes, a signal is sent to the VFD pump to maintain a cell voltage of 1.98 volts. By maintaining this voltage the copper content in each cell exits at 2-4 grams per liter. This safely optimizes the arsenic removal as copper arsenides on the liberator cathodes.IntroductionDuring the electrolytic refining of copper, impurities from the copper anode report both to the bottom of the electrolytic refining cell as slimes and to the electrolyte. The impurities which enter the electrolyte are arsenic, antimony, bismuth and nickel. The impurities that report to the electrolyte during the electrolysis process gradually increase. As these impurities increase, they are incorporated into the refined copper cathode. There are many processes that have been used to remove these impurities from refinery electrolytes. Some of them are listed as follows: solvent extraction, ion exchange, hydrogen sulfide reduction, bioreactor, adsorption onto a low - solubility metal-oxide hydrate, adsorption onto activated carbon and EMEW cells. The conventional process used by the copper refining industry for controlling the level of impurities in electrolyte involves multistage electrolytic cascading liberator cells. In these cascading liberator cells copper, arsenic, antimony and bismuth are removed as various mixed deposits from the electrolyte. Removal of these impurities is achieved through an increase in voltage resulting from the depletion of copper in the electrolyte through electrowinning. With this higher voltage, the Group Vb elements, arsenic, antimony and bismuth are deposited on the copper cathode and report as slimes to the bottom of the cells. Nickel is removed in a subsequent process."

Jan 1, 2012

By Farouk Tedjar

The growth of miniaturization in one hand and energy density need lead to rapid development of new chemistry for batteries as observed during last decade particularly in secondary systems. However dark side of the progress is always in environment impact and scarcity of resources. In the lithium segment a jump from six electrochemical series (all non rechargeable systems) before 1990 to more than 15 systems including new rechargeable systems has been observe during last decade. Lithium battery chemistry was enriched with new electrolytes, conductive salts and new oxide composition. In the same time, lithium ion battery safety was strongly improved during last period. The progress of these technologies was strongly boosted by the substantial growth of the mobile telephone market in the mid 1990's (+ 1% a month in 2000, and a 71% penetration rate in Europe in 2005 compared to just a few percent in 1996). This market is constantly in search of higher electrochemical performance (mainly energy density in front of increasing miniaturization. Recycling of end of life product could be managed not only in environment aspect, but also under resource conservation and economic aspect of arising technology (mainly on the effect of re-injection recovered materials) The Li-ion segment is a new branch in the cobalt market and impact of LiCoOx will be fitted with the actual increase of the demand for this battery. For this reason all the processes aim to valorize active and packaging material. RECUPYL process project was conducted in this direction to offer a new solution for recycling those lithium systems. The process has been developed at pilot industrial scales using synergy between new equipment (for mechanical pre-treatment step) and existing line at RECUPYL facility (for chemical treatment) and should lead to high valorization rate with a minimum hazardous co-products. The process was also developed in order to be able to recover news cathode materials introduced in electrode like LiFEPO4, LiMxCoyO2 and new anode composition in substitution with former carbon anode.

Jan 1, 2006

By Zhu Fangyi

"The article introduces the process EAF with De-P hot metal charging for Melting Stainless Steel in Baosteel stainless steel Branch. Based on the practice of production, the main effect on the Cr Loss during EAF with De-P Hot Metal Charging Melting Stainless Steel including using oxygen, the material charging and making slag are theoretically analyzed. The optimization of using oxygen can reduce the oxidation of Cr during EAF Melting Stainless Steel. The optimization of material charging, especially Si content is suitable can reduce the loss of Cr. Effective reduction can realize the lowest Cr oxide in slag. Based on the character of the process EAF with De-P hot metal charging for Melting Stainless Steel, applied the integrated control method, the Cr loss during EAF melting stainless steel decreased 43.10%. 1 INTRODUCTION EAF with De-P HM charging for melting stainless steel is a technology for stainless steel making. Practice prove that the new process can shorten tap to tap time, reduce the special power consumption, dilute the impurity element from the stainless steel scrap that is propitious to produce the high quality stainless steel, alleviate the shortage of stainless steel scrap to the production. As a new technology, the process has some technical problems and difficulties. The proportion of Cr alloy charging exceeds 20% during EAF with De-P hot metal charging melting stainless steel. As Cr alloy is difficult melting and easy oxidation, too much Cr alloy charging result in Cr loss too much and tap to tap time too long for EAF production. By applying the new technology, Baosteel stainless steel branch has increased the technology level and economy index. Now the content of Cr oxide in slag reduce from 8.59% to less than 6.0%. The Cr loss during EAF melting stainless steel decreased 43.10%. According to the practice application, the process of EAF with De-P HM melting stainless steel are theoretically analyzed. The main factors affecting the Cr loss during EAF with De-P hot metal charging melting stainless steel are discussed."

Jan 1, 2008

By Alexander A. Knminskii

Polymorphism of BaR2F8 compounds is analyzed, and some peculiarities of obtaining monoclinic low-temperature (3-BaR2F8 crystals (R=Y, Ho-Yb) and orthorhombic high¬temperature a-ßaR2F8 crystals (R=Yb, Lu) by the Bridgman-Stockbarger growth technique are discussed. We pay a special attention to BaYb2F8:Er3+ crystals, which are able to generate both 2:µm SE using the new four-level operating scheme (4F9/2?4I11/2 laser channel) and 2- and 3-µm SE by means of the cascade scheme (4F92?+4I11/2?+4I31/2). This 2-µm generation of Er3+ ions has an advantage over similar SE of Ho3+ and Tm3+ ions (especially under diode laser pumping), that is important in designing the medicine and ecology laser. We report on orthorhombic BaR2F8 crystals with the ordered structure, a new crystalline materials for generating Ln3+ ions. The growth conditions are determined and orthorhombic BaLu2F8 crystals of several cm3 in volume doped with Ce3+, Nd3+, Ho3+, Er3+, and Tm3+ ions are obtained for the first time. Spectroscopic and laser characteristics of these crystals are discussed for Nd3+-and Era+-doped samples serving as representative examples. In particular, low-threshold stimulated emission was excited in 4F3/2?+4I11/2 channel of Nd3+ ions in the BaLu2F8. Room-temperature generation was obtained also at -1.317 µm wavelength for Nd3+ and at ~2.8 µm (several lines) for Era+ ions in this new laser crystalline host with a threshold of about 20 J.

Jan 1, 1997

By Andrey Tarasov, Erki Unn, Valery Paretsky

"The stability of the markets of energy resources and labor in countries of the Baltic Sea Region including Estonia is determined to a significant degree by the use of combustible shales as fuel and their distillation resulting in generation of up to 70% of non-recyclable waste. The objective of this business plan is to substantiate the investments for establishment of a new facility in Estonia for waste-less and environmentally safe processing of fossil minerals and man-made products generated in the shale industry, as well as other hazardous wastes. The proposed facility will use a basically new waste processing technology developed in Russia - i.e., processing in sparged molten slag This technology eliminates any release of harmful pollutants to the environment and a facility using this technology does not require, therefore, any sanitary protection zone.IntroductionIn the Baltic region, and first of all in Estonia and some other European territories, there are large natural deposits of combustible shale, which due to the lack of other own resources of energy and hydrocarbons for the chemical industry is burned and distilled with low technical and economic efficiency generating large amounts of toxic and highly toxic wastes and intermediate products. Currently, the penalties for disposal of such wastes have grown to such an extent that shale burning and distillation might become unprofitable. This might result in suspension of the given operations, which in turn will affect in an adverse way the markets of energy resources and labor market in those countries. Furthermore, in addition to the “shale problem”, Estonia, similarly to most member countries of the European Union, faces the challange of environmentally safe processing of highly toxic wastes, such as municipal solid wastes, oilpolluted materials, medical wastes and infected materials, spent rubber tires, etc. These wastes are at present stored or processed with release of a significant quantities of extremely toxic cancerogenic substances (dioxins, furans) or collected and exported for treatment at an extremely high cost and with a loss of valuable components contained in these types of waste and often with return of supper toxic processing products."

Jan 1, 2008

By M. Somerville

In 1989 CSIRO Minerals initiated investigations into continuous converting of copper matte into low sulphur blister in Sirosmelt type reactors. Following the successful piloting of this processing route, some effort was directed towards a single stage copper making process where copper metal is made in one step from concentrate. The aim of the project is to develop a continuous process, which offers considerable environmental and economic benefits over conventional copper making processes, which use Pierce-Smith converters. In the selection of the optimum flowsheet a number of slag treatment options have been considered and tested. These unit operations include: leaching and electrowinning, flotation-leaching-electrowinning and flotation with recycling of recovered copper through the smelting vessel. In this paper the suitability of these process options are evaluated using the available information and recently measured copper recoveries from our testwork at CSIRO. The operating and capital costs of the various options have been estimated using Aspen Plus simulation procedures. The most attractive flowsheet in terms of capital and operating costs is the treatment of slag using mineral processing techniques and the recycle of a copper slag concentrate to the smelting vessel. It has been found that the chemistry of the slag being treated has a large bearing on the recovery of copper in flotation and hence on the economics of the process.

Jan 1, 1999