Industrial ecology is a field of study that encourages the use of closed-loop material cycles to achieve sustainability. Loop closing requires the movement of materials over space, and has long been practiced in the iron and steel industry. Iron and steel (ferrous) scrap generated in the U.S. is increasingly exported to countries in Asia, lengthening the transportation distance associated with closing the loop on the iron and steel life cycle. In order to understand the environmental cost of transporting this commodity, an activity-based maritime transportation model and a theoretical in-land transportation model are used to estimate emissions generated. Results indicate that 10.4 mmt of total emissions were generated, and emissions increased by 136 percent from 2004 to 2009. Increases in the amount of emissions generated are due to increases in the amount of scrap exported and distance it is transported.

Today, the alloy content in steel scrap deliveries in Sweden are determined by the waste management company by test melts. Random sampling analysis (RSA) is an alternative method, under development, to determine the alloy composition of steel scrap. This method evaluates the alloy composition of the steel delivery based on a number of randomly chosen steel scrap unit. RSA is a surface analysis, it is done on a distributed area where with the help of a grid, marks the random steel scrap units for evaluation. This means that the surface fraction determines the odds of analyzing the steel scrap. In a previous study of RSA, 100 random pieces of scrap units was evaluated for its alloy composition with Optical Emission Spectroscopy (OES). These scrap deliveries were thereafter sent to an Electric Arc Furnace for melting. This was done to compare the RSA analysis with samples taken after scrap melting. The RSA study however assumes that the scrap units have the same weight. In this study, the weights of the scrap units in the RSA was assumed to have a variance. Using MATLAB® and the alloy composition data acquired from the old study, a simulation was made where 100 pieces and 100 analyses was made to see what the margin of error in comparison to the old study. Another goal with this study was to see if the variance of the weight had any relation to the absolute deviation of each element in the alloy composition. The results showed that there was no relation between the absolute deviation of each element and the weight distribution in the population. This indicates that there are other factors involved other than the weight distribution in the samples. The average margin of error for all the elements was calculated to 5.94% for the weight distribution of 0.1:0.1:10 kg. This indicates that RSA is accurate or close in analysis for old steel scrap deliveries even if the weight distribution is 0.1:0.1:10kg. The highest margin of error was obtained for W, Ce and Ti with a margin of error of 18.6%, 14.89% and 10.71% respectively. All the other elements had a margin of error beneath 10%. This indicates that for RSA on old steel scrap deliveries a margin of error of 10% would be a good benchmark on the accuracy of the analysis.

Målet har varit att öka andelen skrotanvändning i omsmältan med hjälp av linjärprogrammering som en optimering vid en aluminiumindustri, vilket uppnåddes. Det har gjorts en nulägesanalys om hur aluminium används, hur produktionen fungerar samt var det faller ut skrot. Följande har en teoretisk referensram upprättats med källor från tidigare problem som lösts med linjärprogrammering, en beskrivning av linjärprogrammering och en matematisk uppställning. Det har också beskrivits hur problemet ställts upp, vilka infallsvinklar som använts och de resultat som optimeringen gett. Det har även gjorts arbete kring den måluppfyllande optimeringen som presenterats efter resultatet, vilket följs av en diskussion och slutsats med rekommendationer för framtida arbete inom ämnet. Optimeringen är gjord både mot volym som målfunktion, vilket ger en ökad användning av skrotet, och med pris som målfunktion, som bidrar till en minskad kapitalbindning i skrotet som finns kvar. Dagslägets användning av skrot uppgår till cirka 30 % per år medan optimeringsmodellen gjord på endast 17 av 72 recept skulle kunna få i så mycket som 90 % av hela årets producerade skrot. En optimering på endast ett recept visar också på att det är möjligt att smälta om och producera gjutlegeringar bestående av hög andel enbart skrot. / The aim with this project was to increase the amount of used scrap in the remelt of aluminum alloys by using linear programming, which was successfully done. A status analysis about the average use and characteristics of aluminum has been described, as well as a mapping of the todays industry within the company. This is followed by a theoretical chapter containing references from previous work solved with linear programming, and a description of LP including the mathematical model. The attempt to solve this problem is carefully shown in the forthcoming chapters together with the different approaches that were used. The results are presented with analysis of each optimization, followed by a discussion and a conclusion including future recommendations. The model is used with two different objective functions to get perspective, volume to maximize the amount of used scrap and price to increase use of high valued alloys in order to decrease capital accumulation within the non-used scrap. The remelt process of today consumes about 30 % of the total scrap produced during one year. This model shows that it is possible, by having 17 out of 72 recipes, to use 90 % of all scrap. One optimization for a single recipe also proved that it is possible to produce an alloy consisting of basically scrap.

This study intends to better control the final composition of steel by trying to have a better knowledge of elements including copper, nickel, molybdenum, manganese, tin and chromium in the scrap. This objective was approached by applying probability and statistical concepts such as normal distribution, multiple linear regression and least square and non-negative least square concepts. The study was performed on the raw materials’ information of Ovako Smedjebacken and Ovako Hofors, two steel production plants in Sweden. The information included but were not limited to the amount of the different scrap types used in the charge, total weight of the charge and the final composition of the produced steel.  First, the concept of normal distribution was used as to consider the variations of the alloying elements between the estimated and measured alloy contents. The data were then used to consider a model for distribution factor of the studied elements. Also, an estimation of the alloy contents in the scrap type given the final steel composition was carried out using the concept of probability and statistics. At the end, a comparison of the results from the different concepts was done.

No description available.

The purpose of this report is to identify the main challenges involved with scrap management in the manufacturing context. The work was conducted in collaboration with Cummins-Scania XPI in Södertälje. In order to conduct the work, a literature review covering the areas of quality management in the manufacturing context was conducted. In the end, Total Quality Management was chosen as the main theoretical framework that was used to identify the organisational challenges for scrap management. With respect to how this work was carried out, a Current State Analysis was used for the evaluation of the case company’s practices. Data gathering was carried out through component testing and interviews. The results indicate that several points for improvement exist in the assembly and salvage lines, with the main ones being adherence to documentation processes, motivation of scrapping decisions, and more centralised data management. Moreover, it was shown that unjustified risk aversion may lead to undue scrapping of components. The results are immediately relevant and useful for the case company but have the potential of being valuable for other companies, as well. Namely, the methodology laid out in this report can be replicated and produce valuable insights in all manufacturing contexts. On the other hand, factors such as type of scrap generated affect the applicability of this report’s findings to different contexts. For instance, production lines with scrap consisting of solid metal parts will find more immediate use from this report compared to production lines with more chemically complex scrap, such as circuit board designs with adhered batteries. / Syftet med denna rapport är att identifiera de huvudsakliga utmaningarna med skrothantering inom tillverkningssammanhang. Arbetet utfördes i samarbete med Cummins-Scania XPI i Södertälje. För att genomföra arbetet genomfördes en litteraturöversikt över områdena kvalitetshantering inom tillverkningssammanhang. Total Quality Management valdes i slutändan som det huvudsakliga teoretiska ramverket som användes för att identifiera de organisatoriska utmaningarna för skrothantering. Med hänsyn till hur detta arbete utfördes användes en aktuell tillståndsanalys för utvärdering av det aktuella företagets praxis. Datainsamlingen genomfördes genom komponenttestning och intervjuer. Resultaten indikerar att det finns flera punkter för förbättring imonterings- och räddningslinjerna, med de huvudsakliga som efterlevnad av dokumentationsprocesser, motivering av skrotbeslut, och mer centraliserad datahantering. Dessutom visade det sig att oberättigad riskaversion kan leda till onödig skrotning av komponenter. Resultaten är omedelbart relevanta och användbara för det aktuella företaget men har potentialen att vara värdefulla även för andra företag. Nämligen kan den metodik som beskrivs i denna rapport replikeras och ge värdefulla insikter i alla tillverkningssammanhang. Å andra sidan påverkar faktorer som typen av skrot som genereras tillämpbarheten av denna rapports resultat i olika sammanhang. Till exempel kommer produktionslinjer med skrot bestående av solida metalldelar att hitta mer omedelbar användning från denna rapport jämfört med produktionslinjer med mer kemiskt komplexa skrot, som kretskortsdesigner med fastklistrade batterier.

The purpose of this report is to identify the main challenges involved with scrap management in the manufacturing context. The work was conducted in collaboration with Cummins-Scania XPI in Södertälje. In order to conduct the work, a literature review covering the areas of quality management in the manufacturing context was conducted. In the end, Total Quality Management was chosen as the main theoretical framework that was used to identify the organisational challenges for scrap management. With respect to how this work was carried out, a Current State Analysis was used for the evaluation of the case company's practices. Data gathering was carried out through component testing and interviews. The results indicate that several points for improvement exist in the assembly and salvage lines, with the main ones being adherence to documentation processes, motivation of scrapping decisions, and more centralised data management. Moreover, it was shown that unjustified risk aversion may lead to undue scrapping of components. The results are immediately relevant and useful for the case company but have the potential of being valuable for other companies, as well. Namely, the methodology laid out in this report can be replicated and produce valuable insights in all manufacturing contexts. On the other hand, factors such as the type of scrap generated affect the applicability of this report's findings to different contexts. For instance, production lines with scrap consisting of solid metal parts will find more immediate use from this report compared to production lines with more chemically complex scrap, such as circuit board designs with adhered batteries. / Syftet med denna rapport är att identifiera de huvudsakliga utmaningarna med skrothantering inom tillverkningssammanhang. Arbetet utfördes i samarbete med Cummins-Scania XPI i Södertälje. För att genomföra arbetet genomfördes en litteraturöversikt över områdena kvalitetshantering inom tillverkningssammanhang. Total Quality Management valdes i slutändan som det huvudsakliga teoretiska ramverket som användes för att identifiera de organisatoriska utmaningarna för skrothantering. Med hänsyn till hur detta arbete utfördes användes en aktuell tillståndsanalys för utvärdering av det aktuella företagets praxis. Datainsamlingen genomfördes genom komponenttestning och intervjuer. Resultaten indikerar att det finns flera punkter för förbättring i monterings- och räddningslinjerna, med de huvudsakliga som efterlevnad av dokumentationsprocesser, motivering av skrotbeslut, och mer centraliserad datahantering. Dessutom visade det sig att oberättigad riskaversion kan leda till onödig skrotning av komponenter. Resultaten är omedelbart relevanta och användbara för det aktuella företaget men har potentialen att vara värdefulla även för andra företag. Nämligen kan den metodik som beskrivs i denna rapport replikeras och ge värdefulla insikter i alla tillverkningssammanhang. Å andra sidan påverkar faktorer som typen av skrot som genereras tillämpbarheten av denna rapports resultat i olika sammanhang. Till exempel kommer produktionslinjer med skrot bestående av solida metalldelar att hitta mer omedelbar användning från denna rapport jämfört med produktionslinjer med mer kemiskt komplexa skrot, som kretskortsdesigner med fastklistrade batterier.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Este trabalho tem como objetivo o desenvolvimento de uma tecnologia para a atenuação do impacto provocado pelo passivo ambiental gerado por pneus inservíveis, conjuntamente ao desenvolvimento de novos materiais compostos para uso na construção.Os pneus têm uma estrutura física especial, com grande resistência e durabilidade, mesmo ao término de sua vida útil e, por isso, sua deposição em aterros sanitários é inadequada, já que eles não permitem compactação, tornando-se favoráveis para a criação de agentes causadores de enfermidades e oferecem grandes riscos de incêndios, o que acarreta sérios danos ao meio ambiente. A tecnologia desenvolvida utilizou a borracha de pneus inservíveis, após serem picados por processo mecânico, segundo diferentes tamanhos, para a composição de produtos de baixo custo e utilizáveis na construção civil em elementos construtivos, placas de amortecimento sonoro e de revestimento de pisos para edificações, sinalização horizontal em vias públicas, absorvedores de impacto em estradas,etc. O agente de aglomeração utilizado foi a resina poliuretânica derivada do óleo de mamona (Ricinus communis), uma fonte renovável, que também apresenta estabilidade física e química, e um excelente desempenho como aglomerante. O composto obtido foi testado com relação à durabilidade, às propriedades mecânicas como resistência à compressão e tração, módulo de elasticidade e fluência por meio da termo análise, demonstrando resultados satisfatórios e confirmada sua aplicação em vários campos da construção civil. / The objective of this work is to develop a technology for the impact attenuation caused by the passive environmental generated by scrap tires, jointly to the development of new composites for being used in construction. The tires have a special physical structure, with great resistance and durability, also in the term of their useful life, therefore, their deposit in landing fields are inadequate, once they do not allow compacting, becoming favorable for the creation of causes of diseases and they offer great fires risks, what causes serious damages to the environment. The developed technology used the rubber of useless tires, after being fragmented by mechanic process, according to different sizes, for the composition of products of low cost to be used in the civil construction in constructive elements, noise reduction plates and lining of floors for constructions, horizontal signaling in public ways, impact insulating in highways, and so on. The agent of mass used was the polyurethane resin, derived of the castor oil (Ricinus communis), a renewable source that also presents physical and chemical stability, and a good bonding behavior. The obtained composite was tested in relation to durability behavior, mechanical properties which the compression forces and tension, and also its modulus of elasticity and creep by use of thermo analisys, demonstrated satisfactory results and confirmed its application in a many fields of the civil construction.

Em qualquer setor onde exista fornecimento de materiais, as decisões da recuperação do material não conforme são relevantes. Este trabalho estuda as decisões da recuperação de material não conforme na indústria Aeronáutica, onde o seu produto final tem um longo ciclo de fabricação e de suprimento e elevado custo o que exige que o tempo dessa recuperação seja o mínimo possível. O material não conforme tem diferentes destinos, podendo ser recuperado através do retorno ao fornecedor ou oficina autorizada, ou ainda ser destruído. Esse trabalho utiliza o conhecimento da Logística Reversa como suporte para essa decisão de recuperação, porém sob a ótica do cliente e não do fornecedor como a maioria da literatura apresenta. Muitas vezes, o custo dessa recuperação é muito maior que o de uma nova aquisição e nesse tipo específico de indústria 95% do material comprado é importado tornando a logística ainda mais difícil. Este trabalho propõe a utilização de um modelo heurístico, que decide o destino do material não conforme. Os parâmetros para medidas de desempenho desse modelo é a comparação de dados do histórico de itens recuperados pela empresa estudada com os dados obtidos pelo modelo heurístico. / In any company where supply of materials exists, the decisions of recovering non-conform materials are relevant. This paper studies these decisions in an aerospace company, which its finished product has a long production and supply cycles with a high cost, what demands that the time of this recovery be as short as possible. The non-conform material has different destinies, being recovered through the return to the supplier or authorized workshop, or still to be destroyed. This paper uses the knowledge of the Reverse Logistics as a support for that recovery decision, however under the customer’s point of view and not of the supplier as most of the literature presents. A lot of times, the cost of that recovery is much larger than the one of a new acquisition and in that specific type of industry 95% of the bought material is imported turning the reverse logistics still more difficult. This work proposes the use of a heuristic model, which decides the destiny of the non-conform materials. The parameters for measures of acting of that model are the comparison of data of the report of items recovered by the company studied against the data obtained by the heuristic model.