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By L. Dornelles, M. H. Prediger, R. de C. de S. Schneider, D. A. R. Lopez

In this work it was evaluated the environmental impact of sunflower plantation for biodiesel production. It was considered, for life cycle analysis (LCA) of sunflower in familiar agriculture in the South of Brazil, data collected in 23 experimental farmings with sowing in the period from August to November (2006 -2007). The LCA has considered the plantation conditions, energetic efficiency, man power, diesel volume, type of machines, fertilizers and pesticides used. From the analysis carried through it was evidenced that the sunflower produced in small scale does not need the use of tractors to have an excellent productivity and low impact. Therefore, the sunflower can be cultivated, with the necessary cares, in periods that do not compromise the man power for other cultures and the sunflower is an alternative so that the familiar property can produce biodiesel.

Jan 1, 2008

By V. Bredykhin

The efficiency of scrap processing depends firstly on reliability of information about its chemical composition. The paper presents the results of the investigation and development regarding solid copper alloy scrap in the range of lump size 40÷300 mm. Nowadays the sorting of lump scrap is done by two methods: 1. Sorting according to metals and alloys is done at places of scrap generation, and further till metallurgical processing each lot has its "certificate"; 2. Hand sorting of scrap is done according to the marks on solid items in special shops using proximate analyzers or manually by experienced workers. This sorting process is labor - consuming low efficient and involves mistakes. The informational method is a promising trend in the copper scrap sorting. The method is direct, i.e. as a result of sorting the chemical composition of each scrap lump or main elements is determined, and assured data of qualitative and quantitative composition are received.

Jan 1, 2006

By Vinay Kumar, Jae-Chun Lee, Abhishek Kumar, Manis Kumar Jha

However, India is rich in ores and mineral, but E-waste recycling is necessary due to the report of national and international studies, which cautioned on the generation, treatment and accumulation of e-waste in India. Current data indicate that the total domestic e-waste generation including imports is around 382979 MT, however waste available for recycling and actually recycled are 144143 MT and 19000 MT, respectively. In which recycling by non-formal and formal sector are 95% and 5%, respectively. On the other hand, India has developed expertise in handling verities of metallic wastes in an organized and safe manner. The development of individual process or combined processes for handling the e-waste is underway. Eco- friendly and energy-saving processes are necessary to comply with stringent environmental regulations. The paper includes the recent trend of e-waste generation, recycling process and its future prospects particularly in India.

Jan 1, 2011

By Q. Chen

The magnetic properties and phase evolution of Nd-lean and/or boron-rich melt- extracted ribbons of Nd98Fe90.2xBx, where x = 6 through 11, have been studied using XRD, DTA, TMA, and VSM. The off-stoichiometric Nd2Fe14B compositions cause additional phases to be present after crystallization and affect the magnetic properties obtained. The crystallization temperature of this alloy series rises with the increasing) boron content. In addition to Nd2Fe14B and a-Fe, Fe3B is detected. It is found that increasing the boron content reduces B, within this composition range. The magnetic properties are directly associated with the relative magnetic phase content in the samples.

Jan 1, 1997

By V. Gel

An analysis of the operation of rotary tilting furnaces has indicated that they ensure better recoveries of metal when smelting lump scrap from aluminum slags, brass and bronze. On the other hand, processing of slags (concentrates obtained by mechanical upgrading) in pear-shaped furnaces results in much lower performance values as might be expected. At the Novgorod metallurgical plant a process for blister copper production in a rotary TROF converter (Outokumpu, Finland) has been introduced on a commercial basis. Smelting of brass and bronze scrap to produce blister copper is carried out using the technology developed in Russia and differing from the Outokumpu technology by the types of flux used and the blowing conditions in fuel burners and for melt oxidation, as well as by the design of gas removal system, the design of nozzles for melt blowing and the use of carbonaceous reductant (coal) for magnetite reduction in slags. Industrial-scale testing has demonstrated that by means of special techniques the 30-tonne converter productivity can be increased by 30% to 40% as compared with its rated productivity.

Jan 1, 2006

By Nexhmedin Lohja

The production of high-carbon ferrochromium in a submerged electric furnace based on double-level technology has some advantages compared to close-type furnaces with one tap hole. These advantages include the reduction of the specific energy consumption for the overall process, good separation of ferrochromium from slag, an effective treatment of raw materials including lean chrome ores (low percentage of Cr2O3) etc. An outline of the operation of this furnace along with the production line of briquettes from fines of chrome ore by using organic and inorganic binders, will be followed by a description of the recent work carried out to improve the energy consumption in this furnace through a pre reduction process of Cr2O3 ores by the off-gas energy recuperated from the furnace and the use of SiC in the feed. A short theoretical analysis of the new work will also be given.

Jan 1, 2006

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006

By B. Wan

The process of synthesizing silica nanopowder by the gas phase thermal oxidation of tetraethylorthosilicate (TEOS) in a diffusion flame reactor was simulated using a commercial computational fluid dynamic (CFD) code. The fuel combustion process and silica particle formation and growth in the flame are modeled. The temperature, velocity and particle size distribution (PSD) fields inside the reactor are computed. Chemical reaction rate and population balance model (PBM) were used to calculate the particle formation and growth and PSD.

Jan 1, 2006

By D. Ducharme, J. Lenz

Operation of the Kidd electrolytic zinc plant commenced in 1972 with a cellhouse capacity of 105,000 tonnes of zinc cathode. The original cellhouse layout consisted of 42 parallel rows for a total of 588 cells. As leaching capacity increased, the cellhouse was expanded to 630 cells. Zinc cathode was manually stripped from plant start-up until the development of a mobile automated stripping system in 1994. Machine development continued until a second unit was placed in production in 1996, from which point, 60 % of the cellhouse was being stripped with the automated system. The final phase of the project was implemented in 1999 with the commissioning of two more automated strippers. This paper describes the implementation of the automated stripping system and its impact on cellhouse productivity.

Jan 1, 2000

Sodium is added to aluminum-silicon eutectic alloys to modify the structure. The ideal amount is about 100 ppm but due to the fact that sodium is lighter than aluminum and can float to the surface where it bums, oxidizes ad volatilizes, a far greater amount is usually added. Furthermore, as the sodium is continually lost from the alloy the optimum amount is only present for a limited time. The net result is a process which is hard to control, produces fumes and a considerable amount of dross. It is shown that by electrochemically titrating sodium through a tube of sodium beta alumina electrolyte that the sodium can be added continuously in a controlled way. As the sodium is added to the bulk of the aluminum, there is no sodium on the surface of the alloy so that little surface oxidation occurs, and no fumes and dross are produced. This leads to an improved product and working conditions.

Jan 1, 1995

By J. W. Perez

In the treatment of process effluents containing metal ions, it is sometimes desired to remove all of the heave metal ions while at other time it is, desired to remove one heavy metal ion from another, selectively. Ion and precipitate flotation processes were evaluated to perform these functions using the copper-iron aqueous system as a model. Because preliminary foam fractionation experiments proved to be relatively inefficient, most of this work has focused on precipitate flotation using both hydroxide and sulfide precipitation. Test results indicate that by proper control of reagents and operating conditions, it is possible to substantially reduce the froth volume over that achieved with foam fractionation and to separate copper from iron selectively. Mechanisms for collector attachment to precipitates were studied.

Jan 1, 1992

By Anurag Tripathi, J. K. Saha, S. K. Ajmani, J. B. Singh

"The quality of steel is a major concern in the metallurgical industry. The control of liquid steel temperature can enhance the level of cleanliness in steel. Ladle is one of the major vessels used to transfer liquid steel between different stations. The heat transfer phenomenon taking place in this vessel needs to be monitored for controlling the liquid steel temperature. A CFD model was developed for prediction of liquid steel temperature during complete process cycle of ladles in direct heats. The model was validated with liquid steel temperature measured at on-line purging station and tundish during teeming from one of the actual steel plant. The accuracy of model was 96 %. The results obtained show insignificant effect of slag thickness, tapping temperature and ladle life on liquid steel temperature in the ladle. However, the importance of initial refractory temperature was noticed. The CFD model developed in present work can generate the thermal history of liquid steel and refractory walls of any ladle at any stage.1. IntroductionThe control of liquid steel temperature is desired to achieve required steel quality. The low casting temperature is detrimental and may result in nozzle blockages due to premature solidification in the tundish. The phenomenon of heat losses taking place in ladles needs to be understood for prediction of liquid steel temperature. The assessment of thermal profile of liquid steel from BOF converter to caster can be done through consideration of heat losses at all points. Hlinka and Miller [1] showed that the ladle pouring temperature varies due to heat losses from molten steel into surrounding refractory layers. The phenomenon of thermal stratification was numerically simulated by Ilegbusi and Szekeley [2]. The effects of slag cover on heat loss and liquid steel flow in ladle before and during teeming to a continuous casting tundish was numerically simulated by Chakraborty and Sahai [3]. Investigators also developed some simple models to predict the steel temperature for some of the processes taking place in ladles [4-9].The present work is an effort to generate the full information about the temperature drop taking place in any ladle throughout its process cycle. This information can be used to predict liquid steel temperature and to take decisions to minimize heat losses."

Jan 1, 2012

By Stella Agatzini

Column leach tests were conducted to evaluate the amenability of poor Greece nickel laterites to heap leaching with dilute sulfuric acid at ambient temperature. The ore tested was a limonitic laterite with less than 1 % nickel and it was subjected to a suitable pretreatment with water prior to it being loaded into the columns, following findings of preliminary research work. The acid solution was recycled after suitable pH adjustment. Factorial designs were used to determine the effects and interactions of the following factors: sulfuric acid concentration, ore column height, ore grain size and ratio of leach solution volume to the ore quantity. The response which were investigated included nickel and cobalt recoveries, codissolution of iron, calcium, magnesium, aluminum, chromium and silica and also sulfuric acid consumption. Experimental error was also detennined. The tests showed that a nickel recovery of 88% could be achieved in 60 days.

Jan 1, 1993

By Mark W. Sajewycz

Creating technology, securing patent rights, and managing a patent portfolio are time-sensitive and dynamic activities. Agreements should be in place with technology partners (employees, contractors, joint venture partners), prior to embarking on research and development projects, so as to mitigate future disputes over patent rights. Technology partners should be educated on patent law basics so as to be mindful of patent bar triggering events. Accurate records must be maintained to capture information relevant for preparation and filing of patent application, including subject matter, names of inventors, and invention date. Developed inventions should be evaluated for whether to file for patent protection, delay patenting until technology is further developed, maintain trade secrecy, or effect deliberate public disclosure. Once decision is made to file for patent protection, time is of the essence, and application for patent protection should be filed as soon as possible, as many countries award patents on a "first-to file" basis. Decisions on where to file are made having regard to potential competitive advantages versus cost considerations, and can be delayed by taking advantage of priority rights recognized in patent legislation of most countries. Once patents are granted, competitors must be policed for potential patent infringement, and legal action may be necessary to prevent patent infringement.

Jan 1, 2006

By I. M. Santos Moraes

Achieving high current efficiencies when operating at high current densities is a goal for every refinery, whether conventional or permanent cathode technology is employed. To obtain higher current efficiency at increased current density at Caraiba's Tankhouse, the production team decided to change the cathode cycle from eleven to thirteen days, reducing cathode cycle to one per anode cycle. The idea was to reduce the anode-cathode spacing and consequently reduce the potential for short-circuiting them. With respect to current efficiency, the overall result was not much better than that obtained with the normal operating conditions. A new attempt to obtain higher current efficiency at high current density was implemented by going back to two cathode cycles per anode cycle, this time reducing cathode life to ten days. This approach yielded the highest current efficiencies. This paper presents the data generated with the three operating conditions: normal practice, a single cathode cycle per anode cycle, and two cathode cycles per anode cycle with a reduced cathode cycle time. It compares the productivity achieved with each set of operating conditions. An analysis of the main operating parameters as well as the advantages and disadvantages involved with each condition is also presented for future reference.

Jan 1, 1999

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 C. J. Lewis

This presentation concerns calcium oxide-better known as high calcium quick lime High calcium quicklime is produced by calcining high calcium limestone, mostly in the many rotary kilns located throughout the United States and Canada. This paper presents suggestions on the handling of lime based on field experience. The subjects covered are chemical analyses, transporta¬tion, lime storage, lime slaking to form a water slurry of calcium hydroxide solids, slurry transportation, slurry viscosity, and scaling of lime slurries. It is hoped that the comments on the foregoing areas will be of use to those designing or operating lime systems.

Jan 1, 1992

By C. P. Broadbent

Due to growing .public awareness of environmental issues and greater sensitivity towards waste management, many countries around the world are implementing more stringent legislation governing the storage and disposal of hazardous wastes containing heavy metals such as As, Sb, Pb, Cd or Hg. These wastes can no longer be dumped without providing clear guarantees that the material concerned is environmentally safe and will not leach toxic elements to the surroundings. In the Netherlands the current dumping charge for chemical waste (i.e. worst category) is $280/t, and for industrial waste this cost reduces to $75/t. If the material can be reused there may be a small positive credit for selling it, for example discard slag as an aggregate to the construction industry. A number of (pyre)-metallurgical operations, mostly associated with the extraction of metals from sulphidic ores, produce arsenic residues in the form of As2O3 containing flue dusts and speises. If the flue dust is of high purity it can be sold, though many traditional uses are being substituted by other materials. In many cases upgrading the quality of the arsenical dusts is not possible for either technical or economic reasons. Traditional practice is to dissolve these dusts in acid prior to precipitation as ferric arsenate, which is at present classified by many countries as industrial waste and can be dumped. Recent work, however, has cast doubt on the stability of arsenates for disposal and alternative disposal routes have been investigated. Tests have shown that up to 10% (dm) As can be incorporated into "glassy" silicate slags with very low levels of arsenic leaching in the cooled product. Calcium arsenate was added to a range of synthetic and industrial slags from the system SiO2-FexOy-CaO-A12O3-AsmOn, under mildly oxidising conditions and quenched subsequently in water. It would appear that this represents an environmentally acceptable method for the disposal of many arsenical residues and there is some optimism that this method will be equally applicable to the disposal of other toxic metal residues.

Jan 1, 1994

By Tracy Morris, Weldon Read, Luis Navarro

"During the leaching of anodic slimes, tellurium dissolves into the leach liquor together with copper and must be removed before the solution is sent to liberator cells for copper recovery. Prior to the installation of autoclaves, tellurium was precipitated using raw slimes that caused a recirculation of tellurium in the leaching circuit. After autoclaves were installed the old leach tanks were converted into tellurium reactors utilizing copper chips, steam and agitation to form a copper telluride precipitate. Tellurium levels of less than 10 rng/L are achieved in a timely manner.IntroductionThe electrolytic refining of copper consists of an electrolytic cell provided with an anode of impure copper, a cathode of substantially pure copper (starter sheet) and an electrolyte made of copper sulfate and sulfuric acid [1]. When a direct electrical current is passed between the anode and cathode inside the cell, the impure copper anode dissolves in the electrolyte and pure copper is plated onto the cathode. During this operation, many of the impurities are deposited on the bottom of the cell as an anodic slime residue composed of insoluble chemical compounds. Slimes are a major source of rare and precious metals in the copper industry [2-5],In the Amarillo Copper Refinery (ACR), the anodic copper slimes are sent to the Precious Metals department in order to extract and then refine the gold, silver, platinum and palladium from them. The remaining impurities, in the form of a soda slag or copper slag are sent to the Hayden smelter for further processing. Copper telluride is sent to the Selenium/Tellurium department inside the plant for selenium and tellurium recovery. During the leaching process of the anodic slimes, copper, tellurium, and other metal species in the slimes are dissolved into leach liquor that cannot be returned to the tankhouse unless the tellurium concentration is below 10 mg/L."

Jan 1, 2012

By Martin Brueggemann

The Tyrone copper solution extraction and electrowinning plant was the first such facility built by Phelps Dodge Mining Company in 1984. Over the next 20 years, the aqueous flow rate capacity of the plant has been expanded from the original design of 12,000 gallons per minute (gpm) to 34,000 gpm to meet production goals in the face of declining copper grades in the leach solutions. The ability to process higher aqueous flow rates through existing equipment comes at the expense of increased organic loss through entrainment to raffinate. These losses of organic (diluent and extraction reagents) can account for up to 10 percent of the plant?s total operating costs. With the recent dramatic price increase of petroleum-based products, these operating costs due to losses are sure to increase. This paper will discuss recent improvements at the Tyrone SXEW plant that have resulted in a 40 percent reduction of organic losses. These improvements include picket fence modifications, new fence materials, organic recovery systems, and operational practices within the solution extraction process.

Jan 1, 2006