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By Tiejun Chun, Marcus Emrich, Jian Pan, Deqing Zhu, Vinicius Mendes

"Joint projects of studies of hematite acid pellet have been implemented to develop technological solutions for using Vale hematite pellet feed in Chinese palletizing plant. Beneficial improvements on the pellets quality were achieved by adjusting the blends composition and using new technology of pre-treating the blended pellet feed with HPGR (High Pressure Grinding Roller) on rotary kiln pellet technology. The drop strength of green balls increased from 3.4 to 6.0 times from 0.5m height, at the same time, the bentonite dosage decreased from 1.5wt% to 0.7wt%. The compressive strength of roasted pellets reaches 2500 N/pellet. The reduction swelling index of roasted pellets is below 15%.IntroductionWith the fast development of steel industry in China, the production of pellets has been further expanded. Pellets are used as a high quality charge for blast furnace and the annual output is around 80Mt pellets [1]. According to the developmental trend, sinter will be replaced by pellets due to the larger environmental impact of sintering plants when compared to pelletizing plants. For example, the specific CO2 emission in sintering process is around 2.5 times higher than in pelletizing process. However, the steel industry of China has been confronted with a serious shortage of domestic pellet feed due to the low iron grade of Run-of-Mine ore despite of huge reserves of iron ores [2]. Therefore, more pellet feed, mainly hematite, has been imported to make pellets."

Jan 1, 2011

By Mitchell L. Spencer, Viswanathan Panchanathan

"Bonded magnets are important category in permanent magnets. They are made by one of the following processes: compression bonding, injection molding, extrusion, calendering. An overview of the various bonded magnet processes and properties of products made with different magnet materials along with their applications are discussed. The main emphasis will be on the use of bonded NdFeB and ferrite magnets.IntroductionBonded magnets are a major growth area in permanent magnets. Bonded magnets are made by any one of the following processes: Compression bonding; Injection Molding; Extrusion and Calendering [1,2]. Compression and injection molded magnets are rigid magnets. Materials used in calendering process produce flexible magnets. Only the extrusion process makes both rigid and flexible magnets. The binders used for the bonded magnets vary depending on the processes. Thermoset, thermo-plastic and elastomeric binders are respectively used in compression, injection and the calendering process. Extrusion molding uses elastomers or thermo-plastic materials. The most co=on magnetic materials, Ferrite, SmCo, Alnico and NdFeB can be used in any of the above processes either alone or in combination as hybrid magnets. Another material that has been developed for co=ercial application is SmFeN. Making the material has been challenging and it is being used in niche market applications in limited quantitiesIn the extrusion process, a highly loaded compound is used to produce strip or sheet and is continuously extruded through a die. In calendering the granulated compound is rolled to produce a continuous wide sheet. In the compression bonding process a uniaxial pressing force is used. These magnets have higher loading compared to injection molded magnets. In injection molding the material is forced into a mold cavity and has lower loading compared to compression molded magnets [2,3]. Most of the flexible magnets are made using extrusion and calendering processes and the most co=on magnet material is inexpensive ferrite. Flexible magnets have been made using rare earth materials, but on a very limited basis.The major advantages of magnets processed by extrusion and calendering are as follows: inexpensive tooling, automation; practically any 2D geometry; fast production rates; no chipping or breaking; a wide range of properties; on-line magnetization; easy to convert (e.g. cut, punch or shape).Compression bonded magnets are inexpensive to manufacture. They have higher magnetic properties compared to injection molded magnets; however lower than their sintered counterparts. The magnet shape is restricted to simple geometries and they require careful handling. Their isotropic nature allows complex magnetizing patterns."

Jan 1, 2013

By Laurentiu Nastac, Ruslan Mudryy

"This paper investigates the solidification of cast energetic materials. An active cooling and heating (ACH) technology and a mechanical vibration (MV) technology were applied to achieve unidirectional solidification during casting and to reduce cracks, gas pores, and shrinkage defects. The design parameters of these technologies were developed via Computational Fluid Dynamics (CFD) modeling and thermal stress analysis. Concerning the ACH technology, the number of cooling/heating sections and their temperature profiles and time sequences were optimized based on the thermo-physical properties of the energetic material as well as the riser and mold diameter, thickness and type. The ACH technology will also decrease the thermal stresses during casting of energetic materials and therefore minimize the formation of potential cracks that may form during the casting process. The MV technology will help to remove air entrapped during pouring process and decrease the detrimental gap size between the projectile and the solidified energetic material.IntroductionCasting processes are widely employed in the manufacture of products with intricate shapes and, in particular, in applications where the material of the final product is sensitive to machining. It is especially useful in processing of energetic materials. The cooling conditions applied in the casting process can affect the quality of the final cast in terms of void formation, residual stress distributions, and mold separation. Substantial shrinkage is also observed due to the density change upon solidification [1-3]. Residual stresses are known to be closely related to the formation of cold cracks and hot tears during casting. The formation of a gap between the mold and the cast material is of critical importance due to its deleterious effect on heat removal and on crack formation. In the casting of energetic materials all these defects can significantly impair the detonation velocity, Gurney energy, and insensitive munitions characteristics of the formulation, and lead to catastrophic accidents in explosives handling [ 4-5]. Imposition of carefully controlled cooling condition is thus critical in optimizing the cast quality that could help avoid such destructive effects."

Jan 1, 2013

By Wing Ka Ng

Substitution of pulverized coal injection by solid biocarbon fuel has the potential to achieve substantial reduction in GHG emissions associated with blast furnace ironmaking. A systematic evaluation was conducted on the performance of solid bio-carbons produced from a single raw biomass source using different pyrolysis technologies. The potential of solid biocarbon in reducing GHG emission of the blast furnace ironmaking process is strongly influenced by its O/C mass ratio. In order to achieve substantial GHG reduction, it is necessary to replace coal injection by solid biocarbon having a low O/C mass ratio. The pyrolysis technology and conditions employed are key parameters influencing O/C mass ratio of the resultant solid biocarbon. Close collaboration between steelmakers and solid biocarbon producers is critical for producing suitable solid biocarbon fuel to replace pulverized coal injection. A successful partnership should pave the way in achieving substantial reduction in GHG emissions of the blast furnace ironmaking process.

By Hao Rang

The article Is specially to Introduce the recovery process of Nb, Mn, P from slags and reutilization techniques of the remaining slags. Nb-Mn-Fe alloys which contain 14-16% Nb, 40-60% Mn can be obtained after using fire refining process of " Blast Furnace-Revolving Furnace-Electric Furnace -Electric Furnace, "meanwhile, phosphorous slags which the content of phosphorus pentoxide Is 29.21%. Further going through wet metallurgical processing and electrowinning technics to recover grading 99°o metallic manganese. Finally, phosphorous slags are grinded finely to be as phosporous fertilizers to be directly used for farmlands. Small particle size (0-8mm) rich slags are mixed with slight solid additions for balling directly, and taken Into blast furnace with blocky slags all together. The remaining tall slags are fully used as constructional materials, slags cement as well as a serial of wall materials, road materials, ground ornamental materials without burning operation and steam curing. The compressive strength range of those materials is up to 15-30 MPa. There is no more solid waste slags effluent In the full technical process.

Jan 1, 1994

By Junwei Han, Wenqing Qin, Dawei Wang, Fen Jiao, Wei Liu

The removal of iron impurity from zinc calcine was studied by magnetization roasting and magnetic separation. The effects of roasting temperature, magnetic intensity, ore grinding, and leaching pretreatment on iron grade and recovery were investigated. The results indicated that iron recovery increased with the increase of roasting temperature or magnetic intensity, while iron grade was always less than 22%, depending on the fact that the magnetite were not liberated completely. The good liberation was difficult to be achieved by ore grinding but was easier by acid leaching, since the magnetite grains were very fine. After the leaching pretreatment, the recovery of 76.31% with iron grade of 53.24% was obtained by one roughing and cleaning. The SEM/EDS analysis showed that a part of sphalerite, zinc ferrite and other gangues were mixed into the iron concentrate, while some of fine magnetite was reported to the tailing.

Jan 1, 2016

By Animesh Jha

The carbothermic reduction of chalcopyrite has been studied in the temperature range 1073 to 1273K in presence of lime. The role of lime during the reduction process is explained and the phase equilibria leading to the metallisation of copper and iron are discussed. The effect of coal and carbon monoxide on the reduction process have been studied and the rate governing steps are identified. This investigation also cites examples of possible mechanisms of physical separation of metallic Cu from iron during the reduction process.

Jan 1, 1992

By Zhi-xiang Cui

Dongying Fangyuan Nonferrous Metals Co., Ltd. has developed a new technology to produce anode copper from concentrates through only two furnaces. This new technology is called the Two-Step Copper Smelting Process. This paper presents the commercial application of the Two-Step Copper Smelting Process and its operating conditions. The key features of the Fangyuan Two-Step Process are as follows: (1) feed materials, including concentrates and flux, are mixed without pretreatment and fed into the Submerged Lance Smelting (SLS) furnace; (2) high grade white metal (WM) produced by the SLS furnace is transferred via WM conduit into one of the two Submerged Lance Converting and Refining (SLCR) furnaces; and (3) the two SLCR furnaces blow alternatively to maintain continuous operation of the whole production chain. The new smelter started operation in October 2015 with a processing design capacity of 1.75 Mt/year of mixed feed and has been operating for over 30 months.

By James W. Reeves

DuPont was the titanium metal pioneer who put the greatest effort into both R&D and commercial sponge and powder metallurgy production. This was concentrated in the period 1945 through 1963. The commercial results were development of the chloride process for TiCl4 using ilmenite, development and improvement of the Kroll process, development of a modified Hunter process to make titanium powder and commercial development of a direct powder process. The powder metallurgical process failed because of the inability to meet powder chloride specifications. All this work remained a trade secret until published in NMAB -392 by Mahla in 1983. There were other processes explored by DuPont, both improved sponge and powder processes. Much of this work has been continued by others but none, as of yet, resulting in new improved titanium metal capacity.

Jan 1, 2001

By Markus A. Reuter, Jacob Wood, Robert Matusewicz

Over the last 20 years, significant improvements in copper smelter productivity have been realized through the advent of continuous smelting processes. This progress has until recently however, not been carried through to copper converting. Peirce-Smith converting has been widely used by the copper industry for 100 years but is limited by its batch nature in achieving large scale of production. A logical next step is therefore copper converting on a continuous basis with its inherent environmental benefits. A number of continuous converting technologies are currently in use or being developed within the copper industry, the majority of these operating with calcium-ferrite slags. A notable exception however is the Ausmelt Continuous Copper Converting (C3) technology which has focused on operation with ferrous-calciumsilicate or loosely called olivine type slags. This paper discusses the merits of the Ausmelt C3 process and the advantages offered in terms of operational flexibility and process control arising from the use of lime modified iron silicate slags. It also examines the effects of key process variables pertinent to continuous copper converting from both a theoretical and experimental/operational perspective.

Jan 1, 2009

By Egil Krystad, Merete Tangstad, Kai Tang, Gabriella Trenell

"A new UMG-Si refining concept has been proposed in this paper. Liquid Si and another liquid metal phase (Me) were separated by the molten slag spontaneously based on their different physicochemical properties. Two metal/slag distribution reactions are able to occur in the system simultaneously. Experimental investigation on the B and P distribution equilibria among Si/slag/Me was carried out in the graphite resistance furnace under the inert atmosphere. The B and P doped silicon was in equilibrium with either the SiO2-CaO or SiO2-CaO-l0%CaF2 slags at 1600 and 1650°C, respectively. The pure Fe and Cu metals were used in order to ""capture"" B and P in the slag phases. B and P in samples were determined by the ICP-MS. B and P distribution coefficients for the Si/slag/Me equilibria were compared with the theoretical calculations. The possible kinetic barriers for the Si/slag/Me three-layer equilibria have been analyzed. The metal contaminations in the three-layer equilibria were also examined. The present study provides a new approach for the refining of MG-Si.IntroductionMost of the impurities in the metallurgical silicon (MG-Si) are rather ""dilute'', ranging from few to several thousand ppms. However, the target impurity levels for upgrade metallurgical silicon (UMG-Si) feedstock are often far below the level of ppm. In such extreme case, the conventional refining technologies face the great technical challenges. B removal by slagging has already been implemented industrially. Removal of Pis frequently carried out by the vacuum distillation. The separating treatments for B and P removals lead to increase refining cost, total CO2 emission and longer pay-back time of solar cell module.It is well known that the phosphate capacities of slags in equilibrium with liquid silicon are extremely lower. However, if we introduce another phase that possesses high ""phosphor capacity"" into the Si/slag system, one would expect to continuously remove P from Si through molten slag to the new ""phosphor capturer"". The so-called three-layer refming concept is thus proposed in the present study. Liquid Si and another liquid phase (Me) are separated by the molten slag spontaneously based on their different physicochemical properties. Two metal/slag distribution reactions are able to occur in the system simultaneously."

Jan 1, 2013

By Stefan Mutz

In Germany the automobile recycling is regulated by law. Current legislation requires that by the year 2015, eighty five w.-t. % of the components from used cars ill be materially recycled. Whilst for 10 w.-t. % of the materials a thermal utilization is certified, there are still some concrete questions that remain unanswered regarding the usability of single fractions. The recent innovative approaches to the concepts of used cars dismantling do not alter the fact that the majority of the materials of used cars still have to pass over the shredder and the connected processing aggregates. The status of the so called SLF (Shredder light fraction) which is about 25 w.-t. % w.-t. in used cars, has not been satisfactorily clarified. Furthermore questions still remain regarding the separation of the NMSF (nonmagnetic metal shredder fraction) which has to be separated in the single metallic fractions like stainless tell, copper, brass, zinc, etc. Attempts of optimization can be found. This paper analyses some of the difficulties being encountered by the automobile recycling industry in Germany, before reviewing some of the innovative approaches that the industry has introduced. Finally the paper goes on to describe the potential of automatic picking. Examples of a series of tests, utilizing this technology, in which a variety of products from a range of shredders were isolated are described in detail. This new technology provides a range of applications to the automobile recycling industry.

Jan 1, 2002

By Binxu Zhaug, Mark Jolly, Xiaojun Dai

"In conventional investment casting process of aluminium alloys for the application of the aerospace industry, to assure the quality of the final casting, usually the foundry uses large runner system which results in low yield, high energy consumption and high GHGs emission. In one case of this investigation, the yield is between 5 ~ 10% which means that the current casting process wastes large amount of energy and generates lots of scraps. By applying a new casting method, the bulky runner system and the melting/holding time are significantly reduced, the quality of the casting is improved, and in the meantime the related energy consumption and GHGs emission are significantly decreased. In the investigation, the energy efficiencies and GHGs emission between the current and traditional processes are calculated and compared.1. IntroductionAs one of the conventional casting process, Investment Casting Process (ICP) and its applications can be traced to thousand years ago [l]. In current casting industry, ICP still plays an important role in the production of small and precious castings with high quality requirements in automobile and aerospace industries. Both casting quality and manufacturing costs which mainly consist of energy costs have crucial effects on the competitiveness of castings in the market. In the production of aluminium alloy castings using ICP, the energy cost and energy efficiency of a casting facility depend mainly on the efficiency of its melting and heat treating performance. In association with the two performances, more than 60 % of the total process energy costs are symbolised in a typical casting facility [2]. Additionally, in conventional ICP of aluminium alloys for the application of the aerospace, to assure the quality of the final casting, typically the foundry uses huge runner system including big risers/feeders which cause low yield, creates lots of scraps and generates high energy consumption. Consequently, there are huge opportunities for casting industry to choose the best practices for potential energy saving. Furthermore, the reasons such as the stringent limitation of environmental legislation in Europe and the pressure of the rising energy price force the casting industry to reduce the energy consumption and greenhouse gases (GHGs) em1ss10n."

Jan 1, 2012

By Ivanildo Hespanhol

"DALYs are a measure of the health of a population or burden of disease due to a specific disease or risk factor. It evaluates the time lost because of disability or death from diseases compared with a long life free of disability in the absence of disease. DALYs are calculated as the sum of years of life lost by premature mortality (YLL) and years of healthy life lost in states of less than fully health, i.e., years lived with a disability (YDL), which are standardized by means of severity weights, thus: DALY=YLL+YLD.WHO has established for wastewater use in irrigation (1) the same reference level of health protection as established for drinking water quality (2), i.e., the additional burden of disease from consuming water irrigated food should not exceed 10-6 DALY(Disability-Adjusted Life Years) loss per person per year (pppy). This level of risk means that a single additional case of disease may occur in a population of 1 million, during a life time (70 years). In a individual basis is equivalent to the occurrence of a mild disease during about 31,5 seconds.Such a restrictive risk is almost impossible to be attained in most developing countries which may not be able to afford the cost of wastewater treatment and of other protective measures, even for restrict irrigation.This paper presents proposals to adapt the reference level of risk to local technical, cultural, economical and social conditions of developing countries on the basis of a risk benefit approach."

Jan 1, 2008

By Klas G. Hultbom

Mercury is present as trace contaminant in many raw materials for metallurgical plants. When such materials are treated with pyrometallurgical processes the mercury is volatilised. Mercury has a high vapour pressure, even at low temperatures, and therefore it is removed only partly by normal gas cleaning processes. The Boliden Norzink scrubbing process removes elemental mercury by converting it to calomel. It is widely used in the base metals industry. This paper gives examples of the application, and also outlines the background for the development of the process. Another technology developed by Boliden for mercury removal is the Selenium filter. This is a fixed bed filter based on the reaction between elemental gaseous mercury and selenium, by which mercury selenide, HgSe, is formed. The mercury selenide is a highly stable compound with extremely low solubility in water and very low vapour pressure. Mercury is removed selectively without any side reactions. Special applications for the selenium filter technology include mercury removal from gases containing sulphur dioxide and geothermal off-gases.

Jan 1, 2003

By J. David Chapman

There are a variety of choices of materials for mineral extraction processing. Traditionally, end users have used metallic piping for fluid handling and little is known about the advantages (or limitations) of non-metallic piping systems. This presentation will review custom FRP pipe systems and their use in severe corrosive and erosive process streams. These systems can be designed to various pressure and temperature ratings and different components (such as resin and glass type) can be varied to suit the process conditions

By D. Gregurek

In non-ferrous metal furnaces the installed magnesia-chromite refractory lining is exposed to several stresses, rather complex in their interaction. Therefore, a detailed investigation and understanding of wear mechanisms through “post mortem studies” is an important prerequisite for refractory producer. Additionally, in order to determine the most suitable refractory products and to improve the lining life of refractories, practical corrosion testing with processing slags is performed. For this purpose the test-facilities, such as induction furnace, rotary kiln but also cup test and drip slag test, allow the best possible understanding of chemothermal brick wear on pilot scale. Prior to testing a complete mineralogical investigation, thermo-chemical calculation via FactSageTM of the slag was carried out. Based on such research results, combined with specific process knowledge RHI Magnesita can recommend appropriate brick lining solutions for non-ferrous metal furnaces.

By Shilai Yuan, Huimin Lu, Zhijiang Gao, Panpan Wang

"Solvent refining of silicon through using Si-Al melts is a valid method to remove the impurities from metallurgical grade silicon (MG-Si) melt. The thermodynamic behavior of impurities Fe, Al, Ca, Ti, Cu, C, B and P in MG-Si during the solidification of MG-Si was studied based on the available thermodynamic parameters and experimental data. The morphology of inclusions was investigated by Scanning Electron Microscope (SEM). The chemical composition of inclusions in MG-Si and Al-Si melt was analyzed by EPMA. It is found that the amount of white inclusion reduces and most impurities are solved into the Al-Si melts. After solidification of Si–Al alloy using induction heating and acid leaching, impurities can be effectively removed. The solidification of silicon from the Si–Al melt is found to be more effective for purification than general silicon solidification.IntroductionPhotovoltaic energy is one of promising energy resources in a sustainable society because of its inexhaustibility and cleanliness. Although the production and installation of solar cells have increased significantly during the last decade, the cost of solar cell installation is still high. Multicrystalline silicon has now become the main material in the photovoltaic market because of its low production cost and because of the relative high conversion efficiency of solar cells made from this material, which has been studied for a long time [1-3].Electronic grade (EG) silicon (99.9999999% Si) is commonly used as the raw material to produce SOG-Si (99.9999% Si). Silicon produced from the chemical routes restricts the development of solar cells due to environment threaten, high energy consumption and low productivity. Purification of metallurgical grade silicon (MG-Si) is a low cost, environment friendly method. Although several metallurgical processes such as directional solidification, vacuum refining and electron beam melting [4], have been developed, the cost reduction and refining efficiencies for manufacturing silicon is still have to be further optimized.In the purification process, it is difficult to remove boron and phosphorus by the conventional metal refining method. The refining efficiency depends on the segregation behavior of different elements in solid silicon and the liquid phase. The segregation ratios of all investigated impurities were found to be much smaller than the segregation coefficients between solid and liquid Al-Si melts [5]. For instance, the segregation coefficient of B in Si is 0.8 at the silicon melting point (1687K), whereas it is around 0.2 when silicon is solidified from Si-Al melt at 1273K. For phosphorus the segregation coefficient is 0.06 when silicon is solidified from Si-Al melt at 973K°C, which is much less than 0.35 for recrystallization from liquid silicon. Since the segregation coefficient of boron in silicon is 0.8, it cannot be removed by directional solidification."

Jan 1, 2014

By Kenshi Kawabata, Mitsuji Ueda, Junko Umeda, Katsuyoshi Kondoh, Kantarou Kaneko

Solid-state recycling process of in-house scraps of machined magnesium (Mg) alloy wastes has been established to directly produce wrought materials via the repetitively plastic deformation by Roll-compaction (RCP) and the conventional hot extrusion. The coarse chips, wasted in machining AMX602 (Mg-6Al-0.2Mn-2Ca) cast billets used for the gate bar used in Electronic Toll Collection (ETC) of the high-way system, were employed as the input materials in this study. RCP process enabled to serve coarse Mg alloy powder consisting of refined grains and intermetallics with no re-melting. They were easily consolidated by hot extrusion, and their wrought alloys showed both homogeneously refined grains less than 1~2 µm by dynamic recrystallization and randomized texture by repetitive plastic deformation on the input wastes. These materials revealed extremely advanced mechanical properties of high tensile strength of 356MPa and high ductility of 14.8%, compared to the originally virgin materials with 270MPa TS and 5% elongation. When applying the same Mg alloy wastes via RCP process to the mass production in the company, the large-scale extruded materials also indicated the superior tensile properties. It means that this direct solid-state process is held as “Up-grade recycle of metal wastes”.

Jan 1, 2008

By R. David Prengaman

During the past several years a new insoluble lead anode has been developed for copper electrowinning. The new anode consists of a rolled lead-calcium-tin alloy sheet attached to a slotted copper bus bar by a soldering process which produces a complete metallurgical bond between bar and sheet. The metallurgical bond greatly reduces the resistance between the bus bar and the lead sheet and the high conductivity does not deteriorate during the life of the anode. The rolled anode thins uniformly and does not suffer preferential grain boundary or internal corrosion commonly seen in cast anodes. The lead-calcium alloy containing a high tin content corrodes slowly because the rolling process produces a uniform, fine grained structure. The wrought product is very strong and ductile; and contains no internal defects, segregation, cracks, or pores which can reduce the life of the anode. Because the anodes corrode uniformly, a high percentage of the anode thickness can be utilized thus extending the life of the wrought anodes. The anode alloy composition which is stable only in wrought form, produces exceptional resistance to passivation during current interruptions. First introduced into liberator cells, the new electrowinning anodes have been specified as the anodes of choice for every new SX-EW tankhouse constructed in the last two years. This paper describes the new anode, its method of construction, service history, and how it differs from present copper electrowinning anodes.

Jan 1, 1987