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The aim of this work was to study the effect of flow rate on the fuming rate/silica flux of liquid silicon in order to gain a better understanding of the silica fuming during industrial ladle refining during silicon production. The formation of silica fume is the results when the liquid silicon is exposed to air. This silica fume has been shown to be a health hazard when breathed by plant workers and increased environmental regulations call for its elimination. This work is being done as part of the FUME project (FUgitive emissions of Materials and Energy) with funding from the Norwegian Research Council and the Ferro-alloys Industrial Research Association (FFF). To examine the silica flux a series of experiments in a medium scale induction furnace were carried out. A graphite crucible with an inside diameter of 11.4 cm was charged with refined or unrefined metallurgical grade silicon. This silicon was melted and air was blown onto the surface at 3 different rates (1, 3.5, 5 LPM). The produced silica fume was collected in a filter and analyzed for particle size and compositions differences. The total mass of the fume produced was used to estimate the silica flux.The silica flux was found to vary with flow rate from 0.00156 moles/s-m2 at 1 LPM to 0.02788 moles/s-m2 at 5 LPM. With no significant difference between refined and unrefined. The particle size and composition were also found to vary with flow rate. The particle size distribution was similar to what was found in industry (75% under 0.01 µm). However, the size of the largest particles was found to decrease with increasing flow rate. Finally the amount of impurities in the fume decreased with increasing flow rate as well. Additionally, in continuation of previous work on small scale oxidation experiments with liquid silicon in a muffle furnace were done and a more in-depth analysis by EPMA was carried out. It was found that addition of calcium increases the oxidation rate, and that the addition of calcium and aluminum results in an oxide layer with multiple phases.

Induction vacuum refining testwork has been carried out for the removal of phosphorus from silicon melts. This work is of interest for the production of solar-grade silicon, since phosphorus is hard to remove from silicon and an important impurity in solar cells.

Climate change is undoubtedly a serious challenge facing the world today, and as a result the preservation of the environment is at the top of the agenda for the international community and national governments. Integrated reporting is a global phenomenon driven by the necessity for better information for shareholders and stakeholders. Sustainability reports in South Africa have gained momentum since King III was released in 2009. The purpose of this study is to determine if Ferroalloy manufacturers disclose their carbon emissions in their integrated reports. A literature study was done and content analysis was used to analyse the integrated reports of Ferroalloy manufacturers. On average the integrated reports of Ferroalloy manufacturers comply 41% according to GRI requirements. Governance related points measured complied on average 51%, while internal standards measured 71%. 86% of organisations make use of external standards to report their emissions on. Direct emissions obtained on average 42% as per GRI G4 requirements, while indirect emissions obtained a score of 50%. Emissions that may occur as a result of the usage of organisations products were reported on at only 11% according to the GRI G4 requirements. / MBA, North-West University, Potchefstroom Campus, 2015

Climate change is undoubtedly a serious challenge facing the world today, and as a result the preservation of the environment is at the top of the agenda for the international community and national governments. Integrated reporting is a global phenomenon driven by the necessity for better information for shareholders and stakeholders. Sustainability reports in South Africa have gained momentum since King III was released in 2009. The purpose of this study is to determine if Ferroalloy manufacturers disclose their carbon emissions in their integrated reports. A literature study was done and content analysis was used to analyse the integrated reports of Ferroalloy manufacturers. On average the integrated reports of Ferroalloy manufacturers comply 41% according to GRI requirements. Governance related points measured complied on average 51%, while internal standards measured 71%. 86% of organisations make use of external standards to report their emissions on. Direct emissions obtained on average 42% as per GRI G4 requirements, while indirect emissions obtained a score of 50%. Emissions that may occur as a result of the usage of organisations products were reported on at only 11% according to the GRI G4 requirements. / MBA, North-West University, Potchefstroom Campus, 2015

A indústria coureiro-calçadista, durante o processamento de peles, produz resíduos que, por causa do método de curtimento empregado, têm cromo na sua composição química. O objetivo geral deste trabalho é mostrar que é possível a reutilização do metal contido nas cinzas oriundas da incineração de aparas de couro como matéria prima na produção da liga ferro-cromo, livrando o meio ambiente de um resíduo perigoso. Trata-se de um estudo para a elaboração de uma liga com as características similares às de uma ferro-liga ferro-cromo alto carbono (FeCrAC) comercial. Uma análise termodinâmica foi realizada simulando o processo de redução do óxido de cromo com o objetivo de fundamentar e de fornecer as condições para a condução de experimentos. Ao nível de laboratório, em estágio preliminar, foi demonstrado que é possível a reutilização do cromo contido nas cinzas da incineração de aparas de couro na produção de uma liga ferro-cromo. Neste caso obteve-se uma liga com 28 % de cromo e 7% de carbono com uma recuperação metalúrgica de cromo de 69%. / The leather and shoe industry, during the process of leather tanning, produces residues that, because of the method used, have chromium in its chemical composition. The general objective of this work is to show that the recycling of the contained metal is possible as raw material for the iron-chromium alloy production, exempting the environment of a dangerous residue. This study is aimed at the production of an alloy with the similar characteristics to those of the commercial ferroalloy HCFeCr. A thermodynamic analysis was carried through, simulating the process of reduction of chromium oxide, to base and give the conditions for the experiments. At the laboratory level, in preliminary stage, it was demonstrated that the reutilization of chromium contained in ashes of the incineration of leather shavings for the production of one commercial ferroalloy HCFeCr is possible. In this case, an alloy with 28% of chrome and 7% of carbon was obtained, with a metallurgical chrome yield of 69%.

A indústria coureiro-calçadista, durante o processamento de peles, produz resíduos que, por causa do método de curtimento empregado, têm cromo na sua composição química. O objetivo geral deste trabalho é mostrar que é possível a reutilização do metal contido nas cinzas oriundas da incineração de aparas de couro como matéria prima na produção da liga ferro-cromo, livrando o meio ambiente de um resíduo perigoso. Trata-se de um estudo para a elaboração de uma liga com as características similares às de uma ferro-liga ferro-cromo alto carbono (FeCrAC) comercial. Uma análise termodinâmica foi realizada simulando o processo de redução do óxido de cromo com o objetivo de fundamentar e de fornecer as condições para a condução de experimentos. Ao nível de laboratório, em estágio preliminar, foi demonstrado que é possível a reutilização do cromo contido nas cinzas da incineração de aparas de couro na produção de uma liga ferro-cromo. Neste caso obteve-se uma liga com 28 % de cromo e 7% de carbono com uma recuperação metalúrgica de cromo de 69%. / The leather and shoe industry, during the process of leather tanning, produces residues that, because of the method used, have chromium in its chemical composition. The general objective of this work is to show that the recycling of the contained metal is possible as raw material for the iron-chromium alloy production, exempting the environment of a dangerous residue. This study is aimed at the production of an alloy with the similar characteristics to those of the commercial ferroalloy HCFeCr. A thermodynamic analysis was carried through, simulating the process of reduction of chromium oxide, to base and give the conditions for the experiments. At the laboratory level, in preliminary stage, it was demonstrated that the reutilization of chromium contained in ashes of the incineration of leather shavings for the production of one commercial ferroalloy HCFeCr is possible. In this case, an alloy with 28% of chrome and 7% of carbon was obtained, with a metallurgical chrome yield of 69%.

A indústria coureiro-calçadista, durante o processamento de peles, produz resíduos que, por causa do método de curtimento empregado, têm cromo na sua composição química. O objetivo geral deste trabalho é mostrar que é possível a reutilização do metal contido nas cinzas oriundas da incineração de aparas de couro como matéria prima na produção da liga ferro-cromo, livrando o meio ambiente de um resíduo perigoso. Trata-se de um estudo para a elaboração de uma liga com as características similares às de uma ferro-liga ferro-cromo alto carbono (FeCrAC) comercial. Uma análise termodinâmica foi realizada simulando o processo de redução do óxido de cromo com o objetivo de fundamentar e de fornecer as condições para a condução de experimentos. Ao nível de laboratório, em estágio preliminar, foi demonstrado que é possível a reutilização do cromo contido nas cinzas da incineração de aparas de couro na produção de uma liga ferro-cromo. Neste caso obteve-se uma liga com 28 % de cromo e 7% de carbono com uma recuperação metalúrgica de cromo de 69%. / The leather and shoe industry, during the process of leather tanning, produces residues that, because of the method used, have chromium in its chemical composition. The general objective of this work is to show that the recycling of the contained metal is possible as raw material for the iron-chromium alloy production, exempting the environment of a dangerous residue. This study is aimed at the production of an alloy with the similar characteristics to those of the commercial ferroalloy HCFeCr. A thermodynamic analysis was carried through, simulating the process of reduction of chromium oxide, to base and give the conditions for the experiments. At the laboratory level, in preliminary stage, it was demonstrated that the reutilization of chromium contained in ashes of the incineration of leather shavings for the production of one commercial ferroalloy HCFeCr is possible. In this case, an alloy with 28% of chrome and 7% of carbon was obtained, with a metallurgical chrome yield of 69%.

Thesis (MBA (Business Management))--University of Stellenbosch, 1996. / ENGLISH ABSTRACT: The ferroalloy industry is, in contrast to the operationally complicated chemical industry, very reliant on the wealth of experience that has been built up by the operating personnel over a long period of time. The industry has not been at the forefront of technical development and has, in many respects, lagged behind in technological development. Information technology is one such area that has not received its fair share of attention. This study resulted from the requirement that the control systems of the submerged arc furnaces at the Samancor Meyerton Works be integrated in such a way that the plant subsystem controllers could operate off a single database. This would ensure that the reliance of the operation on the experience of personnel could be reduced by the judicious application of data from the process. The integration was expanded to include the control of the electricity generation plant that will utilize the waste gasses from the submerged arc furnaces to generate the electricity. The boundaries of the study were subsequently expanded to include a proposal for the integration of the control systems into a management information system for the Meyerton Works. The study gives consideration to the theory underlying management information systems after the strategic issues of the Manganese Division of Samancor are discussed. The theoretical aspects of management information systems together with the strategic issues of the Manganese Division are brought together to form the practical proposal of the integrated control and management information system. The case studies considered are based on two incidents that occurred on one of the submerged arc furnaces where the resulting financial losses were substantial. An integrated control system would have reduced the financial losses significantly. Finally, the recommendations of the study are firstly, that the management information system as proposed be expanded to include the furnaces that were not originally envisaged to have their control systems integrated, secondly that the maintenance management function be integrated with the control systems and management information system, and finally that the production planning system be included in the management information system so as to give substance to the control and optimization of the flow of manganese units from the mines to the customer. This will entrench the position of Samancor as a world class supplier of manganese units. / AFRIKAANSE OPSOMMING: Die ferroallooi industrie is, in teenstelling met die chemiese nywerheid wat 'n ingewikkelde bedryf het, afhanklik van die ondervinding van personeel wat oor 'n lang tyd opgebou is. Die industrie was nie 'n baanbreker ten opsigte van tegniese ontwikkeling nie en het ook grotendeels agtergebly op die gebied. Inligting tegnologie is een van die gebiede wat nie die gewensde hoeveelheid aandag gekry het nie. Hierdie studie het sy oorsprong gehad in die behoefte om die beheer sisteme van die dompelboog oonde van die Meyerton Werke van Samancor te integreer sodat die beheerders van die subsisteme van aanleg vanaf 'n enkele databasis kon funksioneer. Dit sou die resultaat gehad het om die afhanklikheid van die bedryf op die ondervinding van die personeel te verminder. Die integrasie gedagte was uitgebrei om die beheer van die elektrisiteits opwekkings aanleg, wat die afgase van die oonde gebruik, in te sluit. Die afbakening van die studie was later verbreed om te dien as 'n voorstel vir die integrering van die beheersisteme in 'n bestuursinligting stelsel vir die Meyerton Werke. Nadat die strategiese aangeleenthede van die Mangaan Afdeling aandag geniet, word die teorie aangaande bestuursinligting stelsels bespreek. Die teorie van die bestuursinligting stelsels en die strategiese aangeleenthede van die Mangaan Afdeling word bymekaar gebring om die voorstel van die geintegreerde beheer sisteem en bestuursinligting stelsel te vorm. Die gevallestudies wat bespreek is, is gebaseer op twee insidente wat op een van die oonde gebeur het waar daar geweldige finansiele verliese was. Geintegreerde beheer stelsels sou die verliese beperk het. Die aanbevelings wat gemaak is, is eerstens dat die bestuursinligting stelsel soos voorgestel is uitgebrei word om die oonde waar die beheerstelsels nie oorspronlik geintegreer sou wees in te sluit, tweedens dat die instandhouding bestuursstelsel geintegreer word met die bestuursinligting stelsel, en derdens dat die produksiebeplanning stelsel in die bestuursinligting stelsel gesluit word. Hierdeur sal die beweging van mangaan eenhede vanaf die myne na die kliente geoptimiseer word om Samancor se posisie as 'n wereld klas verskaffer van mangaan eenhede te verstewig.