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By Zhangm Mingming

Three samples received from the EAF shop were characterized by chemical, X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM) methods. The objective of this characterization work was to investigate the occurrence of nickel, copper, zinc, sulfur and phosphorus and to identify their origin and associations with iron minerals in the concentrate samples from the mines. The samples were identified as MINERAL, PELLET, and HRD. The latter is the DRI product. All three samples were received as fine powders. The results indicate that, in the mineral sample, magnetite is the major iron oxide mineral with hematite as a second phase based on the OM and XRD studies. Pyrite [FeS2], chalcopyrite [CuFeS2] and bravoite [(Fe,Ni)S2] are the major sulfide minerals. Trace amounts of apatite [Ca5(PO4)3(F,Cl,OH)], wardite [Na4CaAli2(PO4)8(OH)8 6H2O], giniite [Fe;(PO4)4(OH)3 2H2O] and vivianite [Fe3(PO4)2 8H2O] were identified by SEM and XRD. Microscopic studies also indicated that most of the sulfide grains in the mineral sample are present either as liberated fine particles (about 10 microns) or as inclusions within the magnetite and hematite grains. XRD studies revealed magnetite as the major mineral with subordinate amounts of hematite and pyrite confirming the microscopic findings. Copper, nickel, and zinc are mainly present as chalcopyrite, bravoite, and franklinite [(Zn,Mn,Fe)(Fe,Mn)2O4] in trace amounts in the mineral samples, respectively. Impurities carry over to the pellet and HRD samples. Chemical analyses of the three iron-bearing samples indicate that sulfur and phosphorus in the pellet sample exceeded the specification. Since liberated pyrite and chalcopyrite particles were observed in both the mineral and pellet samples, magnetic and flotation processing routes should be effective for sulfide removal but at the cost of iron losses. The high phosphorus content of all three samples indicates that there are phosphates which are difficult to remove by the current concentrating processes (magnetic separation and flotation).

Jan 1, 2012

By Petr Stehlík

"This paper is aimed at showing and demonstrating progress in technologies and improvements in units for the thermal processing of various types of waste. The following areas are covered: units for the thermal treatment of hazardous industrial waste and common MSW, technologies for the thermal treatment of industrial and sewage sludge, utilizing waste in cement production (material and energy recovery), up-to-date off-gas cleaning systems, original and unique units for the thermal processing of polluted gases, low-NOx burners. The paper represents a review based on industrial applications, papers published in reputable international journals and a monograph under preparation.IntroductionThe present contribution is an overview of the activities and achievements of the Institute of process and environmental engineering (UPEI) of the Brno University of Technology (VUT). The Institute belongs to European leading teams in the field of the thermal processing of various types of waste. The research in the institute currently revolves mainly around a strategic project “Waste and Biomass Utilization focused on Environment Protection and Energy Generation” that is supported by the national government. Due to the limited space this paper is conceived as a review of papers published especially in reputable international journals.Main (strategic) target of the research is development of new, efficient processes (eventually modernized processes with novel original elements) for effective and highly efficient treatment of waste and biomass, including their maximum utilization as renewable energy sources while minimizing harmful emissions. To this purpose, highly advanced know-how for the design and construction of the related technology lines is being developed, supported by mathematical modeling (see e.g. [1]), experimental validation and optimization.Municipal and Industrial Solid Waste – Concept of Waste-to-Energy CentersThermal processing of various types of wastes is not only waste disposal and/or treatment at present. It has to be regarded as waste to energy process wherever and whenever possible and feasible. This observation was at the origin of the concept of new regional Waste-to-Energy Centers (WTEC), outlined in the following paragraphs. The proposal of the centers is based on a combination of experience, know-how and sophisticated approach. The main fact influencing the concept of WTEC is the necessity to treat different types of wastes. Typical types of wastes as well as main products of the processes in a WTEC are shown in Figure 1."

Jan 1, 2008

By Larry M. Southwick

The smelting of copper and other non-ferrous metals have made considerable advances over the last 125 years. Many of the ideas and processes currently in use were attempted early in the history of smelting and were unsuccessful. Often the cause was incomplete understanding of the metallurgy involved, inadequate refractories, poor materials of equipment fabrication or trying too many new ideas at once. With time, these problems get solved and the technologies become commercialized .These were processes whose time had not come when originally proposed, but did eventually. On the other hand, there have been some concepts whose time will never come. They were impossible then and they are impossible now. The people that dream these up were either crackpots (they didn't know what they were doing, but thought they did), or charlatans (they knew they didn't know what they were doing, but didn't care). Both rely on bad science to propose metallurgical absurdities. These too have their place in the development of technology, though mostly negative, and several examples will be discussed in this paper. Three from around the turn of the century will be covered, as well as one from this decade. The last demonstrates that the art of creating absurdities has not withered, even after ninety years of scientific sophistication, and some can even be patented. The first three reached field trials due to the gullibility of company management. The last arose from a fortuitous mis-operation of a plant which solved a problem, but the explanation and patent which arose are metallurgically impossible.

Jan 1, 1999

By Mitsuru Tanahashi

Oxidation removal of boron from molten silicon by injecting oxygen and highly basic CaO-CaF2flux powder has been investigated with special attention to the dynamic behavior of the injected flux particles and gas bubbles. Since oxygen gas is injected into the melt, high oxygen partial pressure is maintained at the flux-O2-Si interface and the removal of boron proceeds under nonequilibrium conditions. By applying this process, boron concentration in metallurgical-grade silicon can be reduced to a single-ppm level. In this paper, the effects of the dynamic behavior of the flux particles injected into the silicon melt and the area of the reaction field (the flux-O2-Siinterface) formed in the vicinity of the flux-gas exit of the injection nozzle on the rate of the boron removal are discussed from the viewpoint of process dynamics. The experimental results clarified that the boron removal rate is affected by the kinetic energy of the flux particles which is determined by the injection conditions, such as the gas-flow rate of oxygen and the size of the flux particles. At higher oxygen gas-flow rates, the injected flux particles are expected to possess a significantly high kinetic energy such that they penetrate the O2-Si interface formed at the nozzle exit, which results in the formation of a new reaction field for boron removal. On the other hand, at lower gas-flow rates, the injected flux particles possess too low kinetic energy to penetrate the interface. In this case where the formation of the reaction field is limited, it is shown experimentally that the rate of the boron removal is constant, independently of the flux injection rate.

Jan 1, 2006

By Robert W. Hyers

Electromagnetic levitation has proven important in a wide range of experiments, all affected by fluid flow. For some experiments such as viscosity measurements, only whether the flow is laminar or turbulent must be established. For other experiments, however, quantitative assessments of velocity, shear stress, or shear strain rate are required. In most cases it is difficult or impossible to measure the internal flow in levitated droplets directly. The samples are usually small, opaque, reactive, high-temperature, metastable, or all of these. Furthermore, recirculating flow limits the utility of tracking surface particles, since they collect in stagnation points ratherthan following the flow. Most research groups have chosen mathematical modeling to assess the internal flow in levitated droplets. A variety of analytical and numerical methods have been applied, including both laminar flow and various turbulence models. A number of these models are reviewed and their impact on different containerless experiments is assessed. Much of the research reviewed here was performed by alumni of Professor Julian Szekely, and by others using similar methods.

Jan 1, 2006

By Tomoya Nihei, Hiroshi Hayashi

"A novel selenium removal process called Recycled Green rust/Ferrite Process is developed by MMC. In this process, a mixed Fe2+-Fe3+ hydroxide compound, green rust (GR), reduces selenate to elemental selenium, while GR is consequently oxidized to magnetite Fe3O4. Sequencing batch-mode experiment showed that the residual selenium concentration gradually decreased with the number of batch test increased. Stable selenium removal was achieved when the number of batch test exceed 15 times. Optimum selenium removal ratio reached 99.95% where initial Se concentration 2.1mg/L decreased to 0.001mg/L. Furthermore, the continuous feeding test carried out through a pilot-scale plant with a feeding capacity 600 L/hr. Approximately 860-hour-feeding test was carried out for the selenium-contaminated groundwater which had an averaged selenium concentration of 0.88 mg/L. Selenium concentration in the effluent from thickener maintained less than 0.01 mg/L (selenium removal rate of 99%) until a net operating time reached 800 hours.IntroductionJapan is one of the largest producers of selenium, and thus there are potential environmental impacts of selenium on soil and aquatic environments. The Mitsubishi Material Corporation (MMC) owns some real estate properties whose soil and groundwater was polluted by selenium and other heavy metals. These sites include former industrial plants: a smelter for nonferrous metal and a fabricating semiconductors and pigments. Selenium in aquatic environment commonly exists in four oxidation states, namely, VI, IV, 0 and -II. Selenate ion (SeO4 2-), the most oxidized form of selenium, and selenite ion (SeO3 2-) are highly soluble and mobile. Elemental selenium (Se0) is insoluble in water and therefore has much lower toxicity. Because selenium is carcinogenic and teratogenic at high concentration, the national effluent standard in Japan is fixed at 0.1 mg/L and the environmental standard at 0.01 mg/L. Although there are several selenium removal techniques, the most conventional process is coprecipitation with a ferric hydroxide because of its simplicity and low cost. It is known that selenite is adsorbed strongly on the surface of ferric hydroxide, but selenate is not. The low affinity of selenate on oxide mineral surfaces was demonstrated by the fact that selenate could be easily displaced by adding competing anions, particularly sulfate ion. Selenate removal from polluted water is one of the most difficult techniques, and more effective methods are desired. MMC developed a novel selenium removal process [1]. In this process, the concentrated slurry that contains Fe(II)-Fe(III) hydroxyl-salts known as Green Rusts (GRs) contributes to selenate removal. The main components of the iron precipitate in the reactor are GRs and their oxidation product, magnetite (Fe3O4)."

Jan 1, 2008

By Roberto Giovanardi, Isabella Lancellotti, Luisa Barbieri, Ercole Soragni, Fernanda Andreola

"Recovery of precious metals (PMs) is a present topic, as they are used almost in every electronicelectric device. Gold is the second PM in order of consumption (following silver) and it is almost ubiquitary in electronics where it mainly finds application to produce bonding wires in integrated circuits and as a coating for contacts and connectors. Given this, discontinued electronic and, with a minor role, electric devices may represent a primary source of PMs as gold mines or jewelery wastes.At present the recovery of gold from such waste is generally accomplished by two strategies: by oxidative thermal treatment followed by metallurgical or chemical processes or by cyanide chemical etching; both techniques do not represent the optimum as the first one deserves a great amount of energy and non-combustible pollutant slag and fumes are produced, while the second procedure comports the use of a highly pollutant agent as cyanide.The aim of this work is the characterization of different electronics scraps to evaluate the gold concentration, and the selective recovery of this metal using enviromentally-friendly techniques. In particular, a new process was developed in order to overcome such environmental and efficiency issues. The process reaches the goal of detach the gold film from the substrate by selective leaching of the supporting metal.IntroductionThe treatment of waste from electrical and electronic equipments is a current topic as their role in modern life is increasing. The disposal of such waste represents both an environmental and an economical concern due to the vast amount of both precious and non precious metals.The use of precious metals (PM) in this field is of primary importance given PM’s unique properties, which give to each of them a specific and irreplaceable role. Silver is the most used, with a demand of over 5000 tonnes per year, mainly for switches and contacts in electric appliances. Gold is the second PM in order of consumption (over 250 tonnes per year and 8% of the total demand) and it is almost ubiquitous in electronics where it finds application to produce bonding wires in integrated circuits and as a coating for contacts and connectors. It is also used as solder in integrated circuits (in alloy with tin) or for wide coatings where it ensures protection against corrosion. Palladium, platinum, rhodium and iridium follow in order of consumption [1- 3]."

Jan 1, 2008

By Robert A. Reiley

Under the traditional environmental paradigm, industry, stakeholders, and government impact the environment through production, consumption, and regulation. For more than twenty years, this paradigm has survived more or less unchallenged. Environmental action has followed a typical pattern: industry pollutes, the public clamors, government enacts legislation, and industry expenditures for pollution-control equipment soar. In the 1990's, many groups realize that command-and-control techniques may not be the most effective method of dealing with environmental issues in the new millennium. The need for regulatory reform became apparent in the 1980's after an accident at the Union Carbide plant in Bhopal, India. In addition, the prospects of an integrated European market and increased global trade sparked a need for common standards regarding the production of goods and services, which led to the adoption of the International Standards Organization (ISO) 9000 Quality Standards. These factors, and others, triggered the development of the Environmental Management System (EMS). Over the past decade, country-and industry- specific EMSs were developed. However, the IS0 realized the need for a single, internationally recognized standard that would be workable for any type organization. The goal of this standard is to promote economic competitiveness, remove trade barriers, and promote environmental protection. To this end, the IS0 14000 Standards were developed to provide business with a structure for managing environmental impacts. This article argues that a new paradigm has begun to transcend the old. Protection of the environment if shifting from "government drivers" to "market drivers". This shift means that industry and stakeholders, instead of government, are taking the lead to develop ways to protect the environment. This article also argues that government can use this new paradigm, in a time of declining budgets and regulatory reform, to continue to protect the environment through increased compliance monitoring and rigorous enforcement. Specifically, the IS0 14000 Standards can allow the government to reduce compliance costs, streamline permit and reporting requirements, and provide business with regulatory flexibility. Finally, this article argues that IS0 14000 will be central to the regulatory reform effort, because it can be internally implemented with little need for legislative intervention.

Jan 1, 1999

By Henrique Ventura Oliveira

Continuous casting is the most important process for solidification of steels. In this process, the fluid flow pattern in the tundish and in the mould have significant effect on the product quality. Problems associated to fluid flow in the tundish include surface turbulence, ?short-circuits?, formation of dead zones and vortexing. During grade changes, mixing in the tundish plays a significant role in determining the length of the intermixed slab. All these flow aspects can be studied by means of mathematical and physical models. In the last years, numerical simulation of fluid flow has become a very popular tool in the analysis of the performance of continuous casting tundishes. In setting-up these numerical simulations, special care should be taken in choosing the appropriate mesh distribution, the interpolation scheme, the adequate location of the inlet boundary and the turbulence model. In the present paper, turbulent fluid flow in different configurations of tundishes was simulated. Different turbulence models were used in the simulations. Residence time distribution (RTD) and mixing curves during grade changes were predicted and compared to results obtained in physical models. The performances of the different turbulence models were evaluated. For the tundishes that have been studied, the performances of the different turbulence models tested in the present work were similar. There is no evidence that any of the models provided sustained improvement when compared to the well-established standard k- model. All turbulence models tested presented limitations in simulating flows under low turbulent Reynolds numbers.

Jan 1, 2006

By Norbert Hort, Karl Ulrich Kainer, Carsten Blawert, Daniel Fechner

"With the development of new heat resistant magnesium alloys, the automotive industry has introduced several parts to the drive train. The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap and the changing legislation will force car manufacturers to take magnesium recycling into consideration. So far post consumer scrap has not been used for magnesium alloy production. Quite a reasonable amount of automotive scrap is likely to end up in a mixed light metal shredder fraction. The separation of mixed magnesium scrap according to several alloys is complex. Therefore secondary magnesium alloys made from blended post consumer scrap would be useful. For this work a matrix of potential recycling alloys was prepared by chill casting and high pressure die casting. The materials were investigated for their microstructure, mechanical properties, heat resistance and corrosion properties. The results will be presented in this paper.IntroductionWithin the last ten to fifteen years several heavy magnesium parts have been assembled in passenger cars, such as gear box housings and crank cases [1, 2]. Reasons are the lately developed new heat resistant alloys and the increasing responsibility of automotive manufacturers to reduce the vehicles weight and thereby CO2 emissions. The latter is pushed by international legislation [3, 4]. The rising quantity of magnesium in automobiles will result in an increasing amount of so called post consumer scrap at the end of the vehicles life.So far magnesium recycling was done only for clean scrap that is free from impurities, contaminations and sorted according to a chemical composition or a single alloy respectively [5- 15]. The latter is also called class 1 scrap and mainly consists of sprues and runners from magnesium die casters [15, 16]. For the upcoming automotive post consumer scrap the materials quality strongly depends on the way end of life vehicles are treated. By proper dismantling of old cars, the bigger magnesium components could be collected and possibly treated similar to class 1 scrap [15]. Up to date automotive manufacturers have no uniform recycling system for end of live vehicles. Most probably a considerable quantity of old cars will be shredded. The resulting light metal shredder fraction will contain aluminium and magnesium scrap, both from several alloys. A separation of mixed magnesium and aluminium scrap is feasible according to [17]. Other authors claimed that the grade of separation of magnesium from aluminium is still not sufficient for a proper industrial recycling process of magnesium post consumer scrap [15, 16]. If an automatic sorting is possible it will probably be very expensive [18]. Therefore, so far the main use of post consumer scrap has been the steel desulphurisation and aluminium production [15]. The use of post consumer scrap for magnesium alloy production has been considered already by [15] and [16] but some problems have to be approached."

Jan 1, 2008

By Ladislav Bebar, Tomas Parizek, Radek Dvorak, Petr Stehlik

"More and more sweeping environmental regulations initiate research, development and introducing into operation up to date technologies for cleaning off-gas and flue gas generated in various branches of industry and municipal waste treatment. The following systems based on novel types of equipment are shown: thermal and catalytic treatment of waste gases polluted by VOC (Volatile organic compounds) and carbon monoxide (alternatively NOx), catalytic filtration for efficient destruction of PCDD/F (dioxins) and potentially NOx, wet cleaning of flue gases polluted by SO2, HCl and HF with a original type of homogenizer “O-element”, integrated equipment for cleaning waste gases polluted by solid particulates, SO2, HCl, HF and heavy metals (alternatively NOx or PCDD/F). The outstanding features of all equipment mentioned above are low investment and operating costs together with high removing efficiency of pollutants. These units can be used mainly in incineration plants, refineries and other chemical plants. The paper represents a review based on papers published in reputable international journals and a monograph under preparation as well as on experience from industrial applications.IntroductionIn the recent years, more and more emphasis is put on preserving clean environment. One of the most closely monitored objects of general public attention are exhaust gases, containing a number of undesirable compounds like NOx, CO, SO2, HCl, HF, fly ash a PCDD/F. These harmful species are created in chemical processes mainly in the industry, transport and energy sectors. There is therefore a strong impetus for abatement of these harmful pollutants. Sectors of industry are thus subject to emission regulations specific to various types of units. In the framework of increasing demand for a clean environment, the concerned legislation is becoming increasingly strict and requires removal of pollutants by modern methods that would ensure efficient abatement of emissions at reasonable investment and operating costs.Attention is focused chiefly on methods for decreasing harmful emissions from thermal waste treatment facilities processing industrial and municipal waste that may be subsequently applied in other sectors of industry. Units for the thermal treatment of waste not only provide means of its disposal, but may become also important sources of energy, provided that strict emissions limits are satisfied. Figure 1 compares emission limits given by the legislation for municipal waste incinerators and limits for a selection of energy sources with heat capacity up to 50 MW (see EU regulation 200/76/EC). The Figure implies that the values of emission limits for waste incineration are mostly comparable with emissions from the combustion of natural gas. Thanks to the continuing improvements of the methods for removal of harmful pollutants, the emissions from waste incinerators are typically deep below the limits."

Jan 1, 2008

By J. V. Happ

The investigation reported in this paper was prompted by the belief that vacuum processing of copper mattes could provide significant advancement to present-day copper smelting and converting technology. Specifically, vacuum distillation of copper mattes in a unit such as the R.H. vessel used in vacuum degassing of steel, can lead to improvements in: converter flue-gas-cleaning system, purity of acid (or liquid SO2), aisle hygiene, purity of electrorefined copper and smelter flexibility. In the study conducted, removal of Volatile impurities (arsenic, antimony, bismuth, lead and zinc) from liquid mattes, by vacuum distillation in a laboratory-scale equipment was performed. The conditions investigated covered a temperature range of 1123-1223K, absolute pressure of 6.5-0.5kPa (50 - 3 mm Hg) and with bleed gas consisting either of pure oxygen or argon. Six matte samples (four U.S. and two foreign) were tested. Under the "best" conditions arsenic and antimony were reduced to << 0.01% in the product matte. The removal of bismuth, lead and zinc was variable and appeared to be influenced by the matte composition of the sample. As might be expected, the rates of distillation of the various species were increased at higher temperatures and lower absolute pressures. The influence of a small flow rate of gas (02 or Ar) over the melt did not have a signifi¬cant influence on the extent of impurity removal. The magnetite content of the matte was reduced by up to 30% during vacuum treatment and was favored by a low partial pressure of oxygen over the melt. Substantial amounts of sulfur were also evaporated and an, overall increase in copper grade of the matte was realized. The paper concludes with an evaluation of industrial aspects of the process as applied to conventional smelters.

Jan 1, 1983

By A. D. Neuman, C. C. Davis, M. R. Lopez, A. C. Martinez, T. A. Nothwang, F. G. Hampel, S. L. Voit

"One of the thrust areas for the Global Nuclear Energy Partnership (GNEP) program is the development of actinide bearing fuels for transmutation in a fast reactor. Mixed Oxide (MOX) fuel has an extensive fast reactor irradiation history and thus is being considered for use as a baseline composition from which minor actinides can be incorporated for use as a transmutation fuel. The current study involves characterization of precursor powders and pellets destined for the Advanced Test Reactor in Idaho. These pellets will have three compositions: one standard MOX composition, (U0.80Pu0.20)O1.98, and two compositions of minor actinide mixed oxide (MAMOX) with oxygen to metal ratios (O/M) of (U0.75Pu0.20Am0.03Np0.02)O1.98 and (U0.75Pu0.20Am0.03Np0.02)O1.95. The precursor powders were characterized using a field emission gun scanning electron microscope (FEG-SEM) to determine particle morphology, size, and size distribution. An electron probe microanalyzer (EPMA) was used to characterize element distributions in the pellets.IntroductionThe fundamental purpose of GNEP is to enable a fuel recycling partnership between member nations. The customer nations utilize the fuel for electricity generation provided by and subsequently recycled by the supplier nation. The supplier nation recycles the actinide constituents, mainly uranium and plutonium, in advanced nuclear power reactors, and thus reducing waste volumes [1, 2]. Nuclear materials are strictly controlled through the International Atomic Energy Agency. One of the thrust areas supported by the GNEP program is the development of actinide bearing fuels for transmutation in a fast reactor under the U.S. Advanced Fuel Cycle Initiative (AFCI) in order to transmute long-lived transuranic actinide isotopes into shorter-lived fission products [3].MOX fuel has an extensive fast reactor irradiation history and thus is being considered for use as a baseline composition into which minor actinides can be incorporated for use as a transmutation fuel [4]. Irradiation performance data on oxide fuels with high concentrations of minor actinides is limited, which has prompted this study. This paper discusses the characterization results of precursor powders and pellets prepared for the Advanced Test Reactor in Idaho to determine the effects of including minor actinides in the fuel, and addresses two fuel test matrices proposed by Hilton et al. [3]. The pellets will have three compositions: one standard MOX composition, (U0.80Pu0.20)O1.98, and two compositions of MA-MOX with O/M of (U0.75Pu0.20Am0.03Np0.02)O1.98 and (U0.75Pu0.20Am0.03Np0.02)O1.95. The precursor powders, uranium oxide (depleted, DUO2 and highly enriched, HEUO2), neptunium oxide, NpO2, americium oxide, AmO2, and plutonium oxide, PuO2, were characterized using a FEG-SEM for particle morphology, size, and size distribution. The morphology of the actinide powders was studied in the areas of flowability and porosity in order to predict manufacturability. The MOX pellets were characterized using an EPMA in order to determine impurity levels and locations."

Jan 1, 2008

By Wolfgang Steffes-Tun

Pyrite ore concentrate from the Meggen mine (FRG) , which contains about 0 300 400 ppm thallium, is roasted in a fluid bed furnace at 1000 -1100 C to form sulfur dioxide and ash consisting mainly of hematite. Subsequently, the sulfur dioxide is separated from the ash or dust during several steps while cooling to about 250oC. The pyrite ash fractions show decreasing grain size down to 5 pm, a pH-decrease down to 2,4 and a marked enrichment of arsenic and thallium by a factor of 12. In the final fraction, the hot electroprecipitator dust of the dump (EGR), minute crystals of thallium-containing jarosite can be detected by analytical transmission electorn microscopy (TEM). Under oxidizing, acid conditions, jarosite may be a possible "reservoir mineral" for immobilizing thallium.

Jan 1, 1989

By Jorge Alberto Soares Tenório

Electronic components have precious metals like Au and Ag. These metals have a high performance in electric conductance. The recycling of the scrap, however is too difficult because of the presence of other metals like Fe, Al, Zn, Sn, ceramics and plastics, all together in electronic components. The aim of the present work was to define one way for physical separation to have metallic non-ferrous concentrates. It was used three kinds of scrap. I was used conventional equipment for mineral processing like hammer mill; screens, electrostatic and magnetic separation.

Jan 1, 1997

By Irina V. Sokol

Alloyed steel chips and swarf formed during metal processing are looked upon as additional raw material In metallurgycal production. The manuscript presents some new methods for steel waste chips and swarf cleaning. One of them Is swarf and steel chips cleaning In ethylene tetrachloride with ultrasonic assistance and following, solvent regeneration. Thermal cleaning of waste chips and swarf provides exit gas products utilization. Catalyst Influence of metal surface on the process of thermal decomposition of liquid hydrocarbons during cleaning process has been studied. It has been our experience that the efficiency of metal waste cleaning technique depends on the storage time of the swarf. Waste chips and swarf cleaning procedures presented in the manuscript have been proved economically advantageous and environmentally appropriate.

Jan 1, 1995

By W. G. Davenport

Chapters 7,8and 9 calculated three combinations of: blast composition (mass% O2, mass% N2) oil quantity per tonne of concentrate blast temperature that will steadily produce molten 65% Cu matte from pure chalcopyrite-concentrate. The combinations are:

Jan 1, 2001

By Mokka N. Rao

In this experimental investigation, the principal operating parameters of the spirals HC 1870 and HG 8/7 are determined for the hydrogravimetric separation of the friable siliceous iron minerals of the Piar Distric, Venezuela. Mineralogical characterization including optical microscopy of feeding materials and the products after separation are presented. Comparative analysis is made of effectiveness of productivity between the two spirals.

Jan 1, 1999

By James D. Navratil

Advances in hydrometallurgy require the introduction of new separation and purification processes, but they can be complex, costly and energy intensive. Chromatographic processes have low energy requirements and possess very high separation efficiencies. However, they have not yet made the great industrial impact that might be expected from their benefits. The large-scale and difficult separation of rare earths would greatly benefit from an improved continuous chromatographic operational device. Truly continuous, multicomponent chromatographic separations may be achieved by means of the continuous annular chromatograph. Work has been Initiated at The University of New South Wales involving the improvement and development of such equipment for the separation and purification of rare earths.

Jan 1, 1990

By Michel G. Drouet

Dross, a major by-product of all processes involving molten aluminum, forms at the surface of the molten metal as the latter reacts with the furnace atmosphere. It generally represents 1 to 5 wt% of the melt, depending on the process, and contains on average about 50% free aluminum dispersed in an oxide layer. Since aluminum production is highly energy-intensive, dross recycling is very attractive from both the energy and the economic standpoints. The conventional recycling process using salt rotary furnaces is thermally inefficient and environmentally non-acceptable because of the production of salt slags. Hydro-Quebec has developed and patented a new salt-free technology using a rotary furnace heated by an electric arc between two graphite electrodes, called DROSCAR®. A 600-kW pilot plant in operation at LTEE is in use to demonstrate the process. This process provides aluminum recovery rates over 90%, using a highly energy efficient, environmentally sound production method. In 1994, 400 tonnes of aluminum dross were treated in this facility and several tests on various types of dross have also been conducted in early 1995. A report on the results will be presented.

Jan 1, 1995