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By Marisa Di Sabatino, Michael Phan Knudson, Mari Juel, Eivind Øvrelid

"A p-type Czochralski silicon ingot doped with boron was characterized for resistivity, minority carrier lifetime, interstitial oxygen, and metallic impurities. Analyses show a peak in resistivity and a dip in lifetime both occur 5 cm from the top of the ingot crown. This peak in resistivity deviates from the expected trend based on Scheil's equation for boron distribution. High concentration of interstitial oxygen in this area suggests that other oxygen-related defects, such as thermal donors and precipitates, may also be present here, and the observed peak in resistivity and dip in lifetime could be attributed to such defects. The low lifetime of 15-30 µs at minority carrier density of 7.5 x 1014 cm-3 is likely due to copper contamination.IntroductionSolar energy resources vastly exceed all other alternative energy resources, ensuring that solar power must play a crucial role in the evolving energy market. The economic viability of solar power in competition with other energy resources depends upon finding efficient, cost-effective, reliable, and controlled methods for solar cell production. In this regard, minimizing waste (such as material with unsuitable electrical properties that hinder solar cell performance) is a vital component of making solar cell manufacturing cost-effective. Impurities affect electrical properties of solar cell silicon in different ways (i.e. [1, 2, 3, 4, 5, 6]). In this work we focus on the role of oxygen and metallic impurities. Understanding oxygen impurities in silicon is critical to solar cell development because oxygen has been attributed with influencing critical electrical properties including resistivity and minority carrier lifetime and thereby potentially hindering solar cell performance or rendering material unsuitable for solar cells.[1, 2] Furthermore, oxygen is a common impurity in the standard type of solar cell silicon, Czochralski (CZ) silicon, due to diffusion of oxygen from the silica crucible into the melt during crystallization. [7] This study investigates the effects oxygen impurities have on the electrical properties of p-type CZ silicon."

Jan 1, 2013

By Andy Judge

"In traditional Permanent Magnet Machines, such as electric motors and generators, power is transmitted by magnetic flux passing through an air gap, which has a very low magnetic permeability, limiting performance. However, reducing the air gap through traditional means carries risks in manufacturing, with tight tolerances and associated costs, and reliability, with thermal and dynamic effects requiring adequate clearance. Using a magnetically permeable, high thermal conductivity material has the potential to improve magnetic performance, while at the same time offering performance advantages in heat transfer.Ferrofluids can be used to improve permeability in the rotor I stator gap. However, there are several tradeoffs in this approach. Fluid immersion comes with an increase in fluid friction loss compared to the windage losses of a traditional system. Isolating the rotating components from the ferrofluid can offset this effect. Also, while the magnetic effect can be positive for gap permeability, leakage flux can increase, and saturation can limit gains. These effects must be taken into account for a system optimized for ferrofluid immersion.IntroductionPermanent Magnet Machines (PMM's) convert electrical energy to mechanical energy in motor applications, or, for generator applications, convert mechanical energy to electrical energy through means of passing alternately polarized magnets past electrical coils. Looking at a simplified version of a PMM, where Rx is magnetic reluctance and <l>x is magnetic flux, we have the circuit shown in Figure 1."

Jan 1, 2013

By Rodney Hundermark, July Ndlovu, Lloyd Nelson, Phillimon Mukumbe, Paul van Manen, Whitey Seyanund, Bart Pieterse, Bertus de Villiers, Diale Mokwena

The 2003 redoubling in power to 68MW on the Polokwane Smelter furnace represented a significant intensification in platinum group metal (PGM) smelting. Combined with onerous ‘green’ PGM concentrate smelting requirements, this yielded conditions unusually corrosive to copper coolers and refractories. This presented unexpected operational and design challenges to reliable crucible operation and maintenance. Combined with specific operational control intervention, development of protective coatings has led to the life of water-cooled copper components improving from 9 to 40 months. The furnace matte endwall was extended in 2010 to address accelerated wear of refractories and the potential risk for contact of copper components by superheated matte. An 18 month planned endwall rebuild cycle has been demonstrated (versus catastrophic failure within 9 months). Finally, benefits including lower energy consumption, improved metal recoveries and higher productivity resulting from operational and in-house design developments will be described, that justify “Celebrating the Mega-scale” in PGM smelting.

Jan 1, 2014

By Andreas Dietrich

Laser off-gas measurement of CO, O2 and temperature has been carried online in EAFs. A visualization screen shows the values of CO and Oxygen and temperature for the entire heat, and includes the status of furnace equipment. The historical data of the heats are stored such that the furnace performance can be evaluated and optimized. A short comparison between laser based and conventional systems has been carried out related to speed, influence of dust, water, pressure, protection for bag house explosions. A high water and/or dust content in the sample does not represent a problem for this type of system. The measurement method works without interruption even under worst conditions such as dirty scrap, carbon injection etc. The installation was developed in conjunction with Marienhuette, Graz. They are 100% scrap based with a tap to tap time of ca. 46 min. Keywords: Laser Measurement, Off Gas, CO, O2, Temperature

Jan 1, 2003

By U. Kammer

The reduction of the lead content in the separator fraction produced during the mechanical processing of spent lead-acid batteries is an important environmental and economical issues. The reduction of lead down to less than 1 percent is very difficult using hydroseparators that are common in battery recycling facilities. Very promising results were achieved performing experiments on a test rig using a new technology in battery treatment: a discharge-type jigging unit. The materials is fed onto the jigging bed and transported through the machine. Due to the intensive movement of the feed, an additional washing effect is also obtained in addition to separation of the lead and plastic fractions. The knowledge gained from this development work at UVR-FIA GmbH in Freiberg, Germany, led to a patent application. This paper focuses on the results of the development work and the start-up and one year's operation of the industrial-scale application at Harz-Metall GmbH in Goslar, Gennany.

Jan 1, 2000

By WenCai Li, Yong Ren, Shuai Niu, Xin Hong

"Temperature measurement is very important in metal smelting process. Many devices are used to realize non-contact temperature measurements. Compared to conventional thermocouple, infrared temperature measurement has it's unique advantages. However, using an infrared temperature measurement at the top of the furnace can not obtain the desired optical signal because of disturbance from slag layer, high-temperature gases and other effects. A real time thermometry system with dual-wavelength radiation was presented to get optical signal emitted from molten metal through bottom-blowing nozzle. Taking into account the advantages and disadvantages of bottom-blowing devices, a MHP (Multiple Hole Plug) bottom-blowing device was used, through which the optical signal was transferred to the infrared thermometer by use of optical fiber. After conversion and analysis in real-time, the result was displayed and recorded in computer. After calibration, it could be a good predictor of temperature trend in a metallurgical process. IntroductionAt the refining stage of steelmaking, in order to achieve predetermined chemical composition and temperature, high-temperature molten steel is refined in a furnace such as converter. Because the refining process involved with chemical components and reaction velocities in the furnace rely on the temperature of steel, it is necessary to know the temperature accurately in real time during the process. And temperature measurement is also helpful for the end-point judgment. The temperature in the refining process changes quickly, for instance, in a converter, 300t molten steel is processed in only about half an hour.At present, traditional way of temperature measurement is using a thermocouple probe mounted on a lifter called a sub-lance. The thermocouple is immersed in molten steel and its temperature is measured during the short period until the thermocouple is fused. Accurate and reliable temperature can be obtained by this method, but in consideration of the discontinuous measurement and the costs, missing the end-point temperature may sometimes occur.According to the above background, a method in which a temperature-sensing element such as a thermocouple is immersed directly in molten steel is not suitable for the continuous temperature measurement because materials having such stability are not available. Therefore, radiation thermometry is promising. There have been some reports on radiation thermometry through an observation nozzle through the bottom or side of a refining furnace [1, 2]."

Jan 1, 2014

By Onder Guney, Erdem Demirkesenm

"In this study, the crystallization behavior and thermal expansion coefficient of a lithium disilicate (LS2) based glass-ceramic derived from SiO2-Li02-AhO3-K2O-ZrO2 system was investigated by using x-ray diffraction (XRD), high temperature x-ray diffraction (HTXRD), differential thermal analysis (DTA) and dilatometer techniques. Analytical reagent grade chemicals were chosen as raw materials for preparing glass batches. Nucleation and crystal growth heat treatments were planned according to DTA results. The amounts of the amorphous and crystalline phases developed during the heat treatments were determined by quantitative XRD. XRD results of crystallized samples showed simultaneous formation of lithium silicate (LS) and quartz in the early stage of the crystallization followed by formation of lithium disilicate (LS2) at higher temperatures. The thermal expansion coefficients of glassceramics were also measured depending on the applied heat treatments.IntroductionSignificant developments occurred in all ceramic materials provide the fabrication of high quality dental implants [1]. Glass ceramic based dental restorations like dental inlays, crowns, bridges and veneers are becoming increasingly popular with their reliable and durable performance [2,3]. In addition to their advanced functional properties, glass ceramic implants especially lithium disilicate glass ceramics also face the esthetics expectations of patients and dentists and in this way they are starting to take the place of metal based restorations today [1,3,4,5]. Lithium disilicate glass-ceramics derived from multicomponent glass systems have some superior mechanical and optical properties comparable to natural teeth [ 6]. In restorative dentistry, mechanical characteristics of biomaterials play very crucial role in order to resist the masticatory forces occurred during biting and chewing [7] According to three point bending test results of Roland, flexural strength of the lithium disilicate glass-ceramics were 400±40 MPa and their fracture toughness (K1c) are approximately 3,3 MPa m112 [2,6]. In addition to high mechanical strength, aesthetic appearance is another important prerequisite as material for dental restorative applications. Translucency and light transmission of the LS2 glass ceramics mimic enamel. Moreover, opacity of the material can also be adjusted depending on the restoration types [2,6, 7]. These superior properties of the LS2 glass ceramics are directly related with chemical composition of the base glasses and controlled crystallization heat treatments [ 4, 7]. The aim of the present work is to determine the effect of heat treatment schedules on the crystallization behavior and thermal expansion of the LS2 glass-ceramics."

Jan 1, 2011

By Art Cooper

Granulation systems are customarily viewed as problem areas in metallurgical operations. The inherent risk of explosion when combining a high temperature melt with water creates a safety hazard. Separation of the granulated material from the quenching medium generally involves equipment that can have significant maintenance and operating costs. Granulation systems&apos; reliability and availability can negatively affect the plant production. Against this background, granulation systems have been treated by design firms and producers as an add-on and a necessary evil. The technology is becoming better understood and solutions to common problems are being found. This paper will discuss typical problems in common systems, and some of the improvements that have been made, with particular reference to non-ferrous applications.

Jan 1, 2006

By Takayuki Watanabe, Yoshiki Shimizu, Yusuke Moriyoshi

"B-C-N nanotubes prepared by a flush evaporation method using a de arc plasma were mainly characterized by transmission electron microscopy (TEM) and electron energy· loss spectroscopy (EELS). The nanotubes obtained· were divided into three types such as carbon boron nitride and carbon or carbon nanotubes surrounded with boron nitride nanotubes. These types of nanotubes were obtained at higher temperatures than about 3000 K, however, these were not formed at lower temperatures than about 3000K. On the other hand, 11anocapsules were· formed at all the experimental temperatures and nanocapsules with a homogeneous phase were obtained at lower temperatures than about 3000 K. The effect of additives on the formation of B-C-N nanotubes was not clear. Based on these experimental data depending on temperatures and corresponding microstructures, the formation mechanisms of both nanotubes and nanocapsules were briefly .discussed 1 Introduction As reported previously, nano tubes have unique electrical properties1, 3) The preparations of nallotupes have been usually carried out by flush evaporation methods using either a de arc plasma or a laser4 -5) By these methods the reaction rate is so rarid that we have no data of intermediate products between initial raw materials and. final products of nanotubes 6-9). So, the formation mechanisms of nanotubes have been mainly speculated only from the microstructures of resultant nanoiubes. In order to have more reliable formation mechanisms, it is particularly important to have the information of intermediate products at the corresponding temperatures. From the viewpoints, we have studied about the effects of temperatures on the preparation of nanolubes. Here we report mi firstly some problems on the preparation of B-C-N nanotubes 10), secondly the effects of temperatures on the preparation of B-C-N nanotubes, and finally the formation mechanisms of nanotubes."

Jan 1, 2000

By Claude Lorenson

"The Spyrometer™ imaging pyrometer brings new dimension of imaging capabilities to temperature measurement technology by combining a high temperature video camera with scanning optical pyrometry. This gives the operators the ability to observe process conditions while measuring the temperature of virtually any object or region in the field of view. Since the lens tube of the camera can be air or water cooled, it is possible to see inside furnaces giving a very good view of many different types of metallurgical processes. Specific benefits in process knowledge and maintenance tasks for furnaces in different types of metal industries are discussed.1-Principles of Imaging PyrometryLens tube, camera and processorImaging pyrometry is the combination of video imaging and computer-driven pyrometry that measures the temperature of certain zones (selected by the operator) within the image viewed on the monitor screen. To obtain a detailed image of the metallurgical process under observance, it is necessary to place the optical objective of the camera close to the process. The Spyrometer™ (which is Quadtek's tradename for its imaging pyrometer) objective is housed in a lens tube that is cooled and permits insertion inside the vessel of interest. The length of the lens tube is chosen on the basis of making sure that the tip of the tube is just beyond the refractories lining the inside of the furnace. In most pyrometallurgical processes, we have found that the most reliable system set-up uses a water cooled shroud to cool the lens tube optics. A sapphire window provides maximum protection from the environment. Even in the case of the water cooled version, there is an air purge for the lens that keeps the objective clean and protects against hot metal splashes."

Jan 1, 1997

By E. Krystad, G. Tranell

"The kinetics of boron removal from liquid silicon during slag refining, as a process step in the production of solar grade silicon, has been investigated by means of small scale mass transfer experimental series at 1600°C, using a graphite crucible. The slags were SiO2-CaO based, with or without addition of approx. 19 wt% MgO. Experiments were carried out at slag-metal ratios of 1 or 2, where the silicon initially contained approx. 250 ppm boron. The metal-slag mass transfer coefficients for boron were found to be in the order of 1-3 · 10-6 m/s and were largely influenced by slag composition. The mass transfer rate was higher for the MgO-containing slag than the slags without MgO. The final equilibrium distribution of boron between metal and slag, LB, was determined to be in the order of 2.3-3.3.I. INTRODUCTIONRecent years have seen a race in industry and research aimed at obtaining a reliable metallurgical route for production of silicon for solar cells (SoG-Si) from metallurgical grade (MG) silicon. Metallurgical routes can successfully challenge the traditional chemical routes for production of SoG-Si if they generate metal of sufficient purity while being less expensive in terms of production cost and energy consumption. Efficient removal of boron is one of the greatest obstacles in the refining of silicon by a metallurgical route, because the segregation coefficient of boron in silicon makes directional solidification unfeasible; in addition, the vapour pressure of boron is not high enough for removal by vacuum refining. However, the thermodynamic properties of boron makes removal from silicon by oxidation possible, and thus the process of slag refining of silicon has been receiving increasing attention as a method for boron removal."

Jan 1, 2012

By Leijun Li, M. M. Mahapatra

"A three-dimensional finite element model with moving heat source was developed for pulsed-laser powder deposition (PLPD) process. Experiments were conducted to study the repair of superalloy components using the PLPD process. During the experiments, IN 625 powder was deposited on a superalloy substrate similar to IN 738. The process was modeled using three-dimensional finite element analysis. Element birth and death technique was used in the finite element model for simulating the deposition of powder layer on the substrate. A moving distributed heat source was used in the thermal model for realistic simulation of the process. Temperature dependent thermal material properties including enthalpy were used for the powder and the substrate in the transient thermal analyses. The fusion zones and peak temperature distributions of the deposits were predicted from the transient thermal analyses.IntroductionPoor weldability is a critical issue of superalloy repairing. The microstructural directionality of the superalloy components are disrupted when repaired by the fusion welding processes. Currently there is no widely accepted method to economically and reliably repair directionally solidified superalloys components. Pulsed laser powder deposition process (PLPD) is a promising repairing technique as the substrate is not severely affected by the heat source.In this study PLPD technology is used as the tool for superalloy repairing. In most of the land based turbine engines the directionally solidified nickel based superalloy similar to IN 738 [1] is used as the bucket material. The turbine engine blade tips are subjected to a combination of extreme operating conditions and corrosive environment. The tip of the nickel based turbine engine blades can be repaired using IN 625 material as suggested in the literature [1-2]. IN 625 is considered to be ductile and strong enough for the purpose of Ni based turbine engine blade tip repair[1-2]. During the present PLPD investigation, IN 625 powder was used as the deposit material on an experimental super alloy substrate similar to IN 738 superalloy used as the cast superalloy for the turbine engine blades."

Jan 1, 2012

By V. J. Ramirez, A. M. E. Noguez, M. J. Navarrete, B. G. Salas, N. T. Robert

"The close die forging stress in truncated conical cavities is evaluated with dimensional analysis. Five dimensionless groups are proposed from the process variables in order to simplify the forging stress determination. These groups are experimentally related and graphically expressed. This methodology can be used to predict the actual forging stress in industrial close die forgingThe use of the dimensionless groups allow to comprise more cases than the presented here, provided similar geometries and operational conditions.Introduction.Closed die forging is essentially a plastic deformation inside a two piece mold (forging die) with the inverted shape of the actual forging geometry. This plastic deformation will always be the result of a compressive stress. There are theoretical models which include complex calculations for the analytical determination of stresses (1, 2, 3, 4). Results of these calculations are approximate, requiring generally ulterior tests to obtain the true operational conditions(5).In this paper, it is presented a simplified approach to the actual compression stress needed in the forging. A well known tool in engineering: the Buckingham's Pi theorem in conjunction with dimensionless groups and a working piece scale model is used. Dimensional analysis will give the dimensionless terms needed to experiment with a selected scale model geometry to make the stress determination. The results presented demonstrate the reliability of this methodology."

Jan 1, 1997

By Pedro A. Netto, Giulio R. Altoé, Sergio N. Monteiro, Ygor M. Moraes, Frederico M. Margem, Gabriel O. Glória

Since environmental issues are becoming more and more important Worldwide. Nowadays, Natural fibers are been used to substitute the synthetic ones. Although PALF fiber is an important natural fiber and its mechanical Properties surpass in various aspects some other lignocelluloses fibers, such few studies have been conducted with the fiber obtained from leaf of PALF plant. In order to better evaluate the mechanical properties and possible applications, this paper aims to improve the elastic modulus of the PALF fiber by Weibull statistics, by evaluating their mechanicals properties and possible applications. The fibers were divided in diameter intervals and the tensile strength and elasticity modulus were measured in each range. The fractured surface was examined using scanning electron microscopy. The results, interpreted by the Weibull statistical method, showed a correlation between the fiber elastic modulus and its diameter.

Jan 1, 2015

By Lucas Nana Wiredu Damoah, Lifeng Zhang

"Increasing demand for Solar Grade Silicon (SoG-Si) due to rising interest in renewable energy has lead to increased SoG-Si Top – cut scraps generated from the multi-crystalline silicon making process. Due to the high cost of SoG-Si and the potential to use the top-cut scraps as feedstock material, there has been increased effort to develop cost effective and efficient technologies. As a result, several methods to recycle the top-cut scraps are currently been applied, and researched. These include settling under gravitation field, which is a slow process to be industrially applicable. Natural settling of inclusions by gravitational force is a slow process and not attractive to the industry. Recent experiments on Top-cut SoG-Si scrap under high frequency, high voltage, electromagnetic field showed that SiC inclusions settled within a short time to the bottom of the crucible and the characteristic rod-like morphologies of Si3N4 inclusions in SoG-Si were not detected. This study investigates the enhanced settling of SiC inclusions and the behavior of Si3N4 particles under the influence of high frequency, high voltage, electromagnetic field in Top-cut SoG-Si.IntroductionThe photovoltaic industry depends on silicon based PV materials either as single-crystalline silicon, or multi-crystalline Si (MC-Si), or amorphous Si [1] for over 90 % of its market share. [2] MC-Si produced by directional solidification of solar grade silicon melt dominates the silicon PV market. During the directional solidification process, SiC and Si3N4 particles within the melt are pushed by the solidification front to the top of the ingot which is the last to solidify. Therefore the top of the ingot is cut generating what is known as top-cut solar silicon scraps. The Si3N4 particles are mainly from the coating material at the inside surface of the silica crucible and from air absorption during the solidification process. The SiC particles mainly stem from the carbon reduction process of the primary production of silicon [3]. Due to the growth of the PV industry as a result of global demand for clean, reliable, and affordable energy [4], there is the need to develop new methods to compliment exiting ones to recycle SoG-Si waste (e.g. top-cut) for sustainability."

Jan 1, 2012

By John R. Howell

"SUMMARYThe process of producing a new cast component requires significant design and development by both the design engineer and the foundry engineer. This effort strives to produce a high quality component at minimum cost. To assist in this development, an analysis system, consisting of several computer programs, has been developed to simulate the metal casting process. This system incorporates analytical geometric solid modeling, finite element analysis, results display, and an innovative technique to model the casting mold with surface boundary conditions.The simulation has produced excellent thermal results and work is in progress to develop techniques to enable use of this data in additional analyses to predict porosity and residual stress. Research is required to produce working parametric formulations of material properties. Software development is required to develop good fluid flow analyses for large. 3D models to simulate filling of and convection in molds.Integrating this system of programs is difficult due to proprietary database structures used by software developers. However, an acceptable means has been accomplished' to move data from one program to another. Further software development is required to facilitate this task. INTRODUCTIONThe process of producing a new cast component requires significant design and development by both the design and foundry engineer. This effort strives to produce a high quality, reliable component at minimum cost in a timely manner. The design engineer needs to know the physical and mechanical properites which can be expected in the actual part at critical areas. This will enable him to design a part with minimum material while fulfilling the performance required. The foundry engineer needs to produce a sound, quality casting with a minimal amount of material In risers, the feeding system and machining stock. This must be done with a minimum· investment in tooling and development time and maximum productivity of labor and capital employed. This task Is continually being made more difficult because of increased competition in the marketplace and the use of castings in more severe service. This has strongly influenced the need for high quality castings.The task of developing a new casting is difficult for both the design and foundry engineer. To assist in this development, Deere & Company has been engaged in the development of an analysis system to simulate material processes. A major portion of this program involves simulation of the metal casting process. This analysis system has evolved into a package of computer programs which simulates casting solidification and subsequent cooling through the finite element method"

Jan 1, 1986

By Peter Fischer

A demonstration plant for QSL technology with a continuous through-put of up to 10 t/h concentrate has been in operation at the Berzelius smelter, Duisburg, Germany since early 1981. In the QSL-process, both oxidation and reduction steps are performed in a single horizontal long cylindrical reactor. In the present demo-reacior, 2.5 M diameter by 22 M long, these steps are separated by a low partition wall with an underflow opening, to prevent backmixing of slag. -Tests on a variety of concentrates, including high-lead Missouri-type material and lower grades, have shown recoveries and consumables indicating very attractive economics. Investment cost estimates further enhance the economic attractiveness. Environmental protection afforded by the QSL system is a major advantage. The process has proven its reliability and versatility and is now ready for commercialization. Continued test work, including smelting secondary lead materials, is planned.

Jan 1, 1983

By Yun Li

In 1999 Yunnan Copper Corporation (YCC) decided to modernise their copper smelter and change the existing sinter plant I electric furnace process to a combination of ISASMEL T and electric slag cleaning furnace. The main aim of the project was to improve the environmental performance and decrease the energy consumption. Generally the project has been successful, partly attributable to the selection of a reliable and fully demonstrated technology. The design capacity for the ISASMELT furnace is 600,000 tonnes of dry copper concentrate per year. The furnace has been running smoothly since heat up in May 2002. YCC expended considerable effort in the preparation for plant operation. An extensive training program for key YCC personnel at the Mount Isa Copper Smelter improved their understanding of the process significantly and ensured successful hand-over of the technology. This paper describes the project history and summarizes initial operating results.

Jan 1, 2003

By Yun Li

In 1999 Yunnan Copper Corporation (YCC) decided to modernise their copper smelter and change the existing sinter plant I electric furnace process to a combination of ISASMEL T and electric slag cleaning furnace. The main aim of the project was to improve the environmental performance and decrease the energy consumption. Generally the project has been successful, partly attributable to the selection of a reliable and fully demonstrated technology. The design capacity for the ISASMEL T furnace is 600,000 tonnes of dry copper concentrate per year. The furnace has been running smoothly since heat up in May 2002. YCC expended considerable effort in the preparation for plant operation. An extensive training program for key YCC personnel at the Mount Isa Copper Smelter improved their understanding of the process significantly and ensured successful hand-over of the technology. This paper describes the project history and summarizes initial operating results.

Jan 1, 2003

By Lucas Nana Wiredu Damoah, Lifeng Zhang

"The use of electromagnetic field to remove suspended particles from metals such as aluminum by pushing to the boundary has been well studied. However, the potential of this method is yet to be exploited for the removal of inclusions from silicon. Considering the increasing amount of Top-cut SoG-Si scraps year upon year, there is the need to harness all the potentials of technologies to recycle this materials to ensure sustainability. This study investigates, and discusses new results on the effect of processing parameters such as composition, coil current, and frequency on the removal of inclusions from silicon under high frequency AC electromagnetic field.IntroductionThe solar cell silicon making industry requires pure and clean silicon in order to maximize the conversion potential of the solar cell material. The conversion efficiency of solar cells is limited by minority carrier recombination at dislocations and those intra-granular defects such as impurities, small clusters of atoms, or precipitates [1]. Recent global developments in the energy sector with a drive for the production of clean, reliable, and affordable energy have stirred a rapid growth in the production of photovoltaic (PV) cells.[2] Thus over the years, silicon based PV cells has seen a lot of growth as it has a PV market share of over 90 % [3] either as single-crystalline silicon, or multi-crystalline Si (MC-Si), or amorphous Si [4]. MC-Si produced by directional solidification of solar grade silicon melt dominates the silicon PV market. During the directional solidification process, SiC and Si3N4 particles within the melt are pushed by the solidification front to the top of the ingot which is the last to solidify. Therefore the top of the ingot is cut generating what is known as top-cut solar silicon scraps. The Si3N4 particles are mainly from the coating material at the inside surface of the silica crucible and from the air absorption during solidification process. The SiC particles mainly stem from the carbon reduction process of the primary production of silicon [5]. For sustainability the silicon in the top-cut silicon scraps must be recovered. Therefore methods for removing non-metallic particles, such as SiC and Si3N4, from the silicon are important in order to recycle the top-cut scraps to a useful feedstock for the silicon solar cells manufacturing."

Jan 1, 2012