Perlite is a volcanic glass which has high amount of silica and alumina. Those properties make it a candidate, if finely ground, for being used as a pozzolan. The studies on the pozzolanic properties of perlite are very limited, and none of them has dealt with the use of perlite in the blended cement production. The aim of this study is to investigate the pozzolanic properties of perlite, and if appropriate to investigate perlite&rsquo / s usability in blended cement production. For this purpose, perlites from two different sources &ndash / Izmir and Erzincan - are used as replacement of portland cement clinker with two different percentages: 20% and 30% by weight of total cement. Then for each different composition, materials are ground with some gypsum in order obtain grinding curves for the resultant cements. After obtaining the grinding curves, a total of 22 cements with two different finenesses are produced by intergrinding and separately grinding the materials for each composition. The obtained cements are used in paste and mortar production so that normal consistencies, setting times, autoclave expansions, and compressive strengths are determined.

Perlite is a glassy volcanic rock that contains approximately 70-75% silica and 12-18% alumina. There are very large perlite reserves in the world (~6700 million tons) and approximately two thirds of these is in Turkey. Due to its high amounts of silica and alumina, at the beginning of such a study, it seemed that it would be worth first to find out whether perlite possesses sufficient pozzolanic property when it is a finely divided form and then to investigate whether it could be used as a pozzolanic addition in producing blended cements. In this study, perlites from two different regions (izmir and Erzincan) were tested for their pozzolanic properties. After obtaining satisfactory results, grindability properties of the clinker, perlites and their different combinations were investigated. Several blended cements with different fineness values and different perlite amounts were produced by either intergrinding or separate grinding methods. The tests performed on the cement pastes and mortars containing the blended cements produced were as follows: Water requirement, normal consistency, setting time, soundness, compressive strength, rapid chloride permeability, resistance to sulfate attack and resistance to alkali-silica reactions. The results showed that Turkish perlites possess sufficient pozzolanic characteristics to be used in cement and concrete industry. Moreover, the properties tested in this study satisfied the requirements stated in the standards for blended cements. The durability of the mortars was found to be improved by 20% or more perlite incorporation.

Perlite is a volcanic mineral. The latest investigations on ground perlite showed that it is suitable for pozzolanic usage. Thus, it is of vital importance especially for countries rich in perlite such as Turkey. The aim of this study is to investigate the advantages and problems associated with using perlite in concrete and to identify accurate methods and amounts of use for producing durable cementitious mixtures. Within the scope of this study, the alkali-silica reactivity of perlite containing cementitious mixtures were compared using four different methods. Expansion mechanism of the mixtures were tried to be understood by measuring the alkalinity of bath waters. In order to cope with early strength decreases caused by perlite addition, activation of the mixtures by chemical and thermal methods were attempted. It was found that chloride containing chemicals are very effective at later ages and sodium containing chemicals are more effective at early ages. Sodiumhydroxide addition to the perlite containing mixtures was found to be detrimental to both the initial and late-age strengths of mortars. It was concluded that perlite addition generally results in a decrease in alkali-silica expansions. However, the expansion of concrete samples should be investigated comprehensively. Thermal curing at high temperatures resulted in a rapid increase at 1-day strengths, however, for better ultimate strengths lower thermal treatments or no-thermal curing were found to be more effective. Compared to the traditional portland cement concretes, high-volume ground perlite concretes have environmental and economical advantages.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / This study presents the use of sodium methoxide as a homogeneous catalyst and impregnated Perlite (potassium hydroxide/perlite) as heterogeneous catalyst for production of biodiesel using Baobab and Marula oil respectively. One factor at a time experimental design was used to study the effect of temperature, time, amount of catalyst and methanol to oil ratio on the transesterification of baobab oil using sodium methoxide as a catalyst. Response surface methodology was used to study the effect of temperature, time, amount of catalyst and methanol to oil ratio on the transesterification of marula oil using perlite as a catalyst. Biodiesel yield produced using sodium methoxide and baobab oil was 96% at 1 hr reaction time, 30 wt.% methanol to oil ratio, 1 gram of catalyst and 60°C reaction conditions. Biodiesel yield produced using perlite and marula oil was 91.38% at 3.55 hr reaction time, 29.86 wt.% methanol to oil ratio, 3.46 grams of catalyst and 70.41°C reaction conditions. Perlite catalyst was reusable for transesterification of marula oil while sodium methoxide was not reusable for transesterification of baobab oil. Baobab and Marula biodiesel fuel properties are comparable to American Society for Testing Materials standard (ASTM).

Made available in DSpace on 2014-12-17T15:41:53Z (GMT). No. of bitstreams: 1 HialeYSS_DISSERT.pdf: 3935527 bytes, checksum: 49a917d8f6b548b50f34324737a29f0a (MD5) Previous issue date: 2010-01-21 / In this work, expanded perlite, a mineral clay, consisting of SiO2 and Al2O3 in the proportions of 72.1 and 18.5%, respectively, was used as an adsorbent for oil in its pure expanded form as well as hydrofobized with linseed oil. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) were used to study the thermal behavior and quantify the percent adsorption of perlite in differents processes comparing the results with the ones obtained using Gravimetric Analysis. In the process of hydrophobization with linseed oil granulometric fractions > 20, 20-32 and 32-60 mesh were used and adsorption tests with crude oil were performed in triplicate at room temperature. The results obtained by TG/DTG in dynamic atmosphere of air showed mass losses in a single step for the expanded perlite with pure adsorbed oil, indicating that the adsorption of oil was limited and that the particle size did not in this process. Linseed oil has performed well as an agent of hydrophobized perlite (32 to 60 mesh) indicating a maximum percentage of 59.9% and 68.6% the linseed with a fraction range from considering the data obtained by thermogravimetry and Gravimetry, respectively. The adsorption of oil in the expanded perlite and hydrofobized pure perlite with linseed oil did not produce good results, characterizing an increase of 0.5 to 4.6% in pure perlite and 3.3% in hydrofobized perlite with granulometric 32 to 60 mesh / Nesse trabalho a perlita expandida, um argilomineral, constitu?do de SiO2 e Al2O3 nas propor??es de 72,1 e 18,5%, respectivamente foi utilizada como adsorvente para petr?leo na sua forma pura expandida como tamb?m hidrofobizada com ?leo de linha?a. Para isso, utilizou-se a Termogravimetria (TG), a Termogravimetria Derivada (DTG) e a An?lise T?rmica Diferencial (DTA) para estudar o comportamento t?rmico e verificar o percentual de adsor??o da perlita nos processos utilizados, em compara??o com a An?lise Gravim?trica. No processo de hidrofobiza??o com o ?leo de linha?a utilizou-se as fra??es > 20, 20 a 32 e 32 a 60 mesh e os testes de adsor??o com o petr?leo bruto foram realizados em triplicata em temperatura ambiente. Os resultados obtidos por TG/DTG em atmosfera din?mica de ar mostraram perdas de massa em uma ?nica etapa para a perlita expandida pura adsorvida com petr?leo, indicando que a adsor??o de petr?leo foi limitada e que a granulometria n?o interferiu nesse processo. O ?leo de linha?a apresentou bons resultados como agente hidrofobizante da perlita indicando um percentual m?ximo de 59,9% e 68,6% de linha?a na fra??o de 32 a 60 mesh considerando os dados obtidos por Termogravimetria e Gravimetria, respectivamente. A adsor??o do petr?leo na perlita pura expandida e na perlita hidrofobizada com ?leo de linha?a n?o apresentou bons resultados, caracterizando um aumento de 0,5 a 4,6% na perlita pura e 3,3 % na perlita hidrofobizada de 32 a 60 mesh

Made available in DSpace on 2016-12-08T17:19:24Z (GMT). No. of bitstreams: 1 Heloiza Doering Gasparin.pdf: 4558205 bytes, checksum: e414bcfd7c4434aa73fcdf59cdf98ff2 (MD5) Previous issue date: 2014-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This investigation study shows the effects of high temperatures and exposure time on the mechanical properties of one perlitic gray cast iron commonly applied to diesel engine cylinder heads. The effects were evaluated in samples which come from three different cast irons, FC300 class, with different percentages of molybdenum and different hardening mechanisms. Two of them have different amounts of molybdenum and the third did not have significant amounts of molybdenum, however, have refined graphite. The high temperature rupture tensile tests were performed on specimens with 10mm diameter, machined from bars 30mm diameter. The tests were performed at room and high temperature (200°C, 300°C, 350°C, 400°C, 450°C, 500°C and 550°C). The exposure times at elevated temperatures, after material heat homogenization, were 0min (default), 60min and 90 minutes. Samples with highest percentage of molybdenum (0.27 wt%) had the best mechanical properties for high temperature conditions. At room temperature, the material with refined graphite had higher strength resistance values when compared to the other two materials. The mechanical properties evaluated by measurements of microhardness, yield strength (0.2%) and specific strain complement the behavior analysis of these properties at elevated temperature. According to the obtained results, the stress strength decreases with the temperature incrementing. This is attributed to the pearlite matrix decomposition occurrence as a result of the carbon diffusion process. The Carbon from cementite goes by diffusion to the graphite, which is the responsible for the increase graphite percentage in the material. Metallographic analyzes indicate the occurrence of this phenomenon. Increases in high-temperature exposure time also contributed to the perlite degeneration. All microstructural evaluation were made by analysis of cementite and graphite percentage, graphite size for different test temperatures and different times of exposure to high temperature. 16 / Este trabalho de pesquisa apresenta os efeitos de elevadas temperaturas e do tempo de exposição sobre as propriedades mecânicas do ferro fundido cinzento de matriz perlítica, material comumente aplicado a cabeçotes de motor a diesel. Foram avaliados três ferros fundidos da classe FC300, com diferentes percentuais de molibdênio e diferentes mecanismos de endurecimento. Dois dos materiais possuem diferentes teores de molibdênio e o terceiro contém teores de molibdênio desconsideráveis, no entanto, possui grafita refinada. Ensaios de tração até ruptura a quente foram realizados em corpos de prova com diâmetro de 10 mm, usinados de um pino bruto de 30 mm de diâmetro. Os ensaios de tração foram realizados a frio (temperatura ambiente) e a quente (200°C, 300°C, 350°C, 400°C, 450°C, 500°C e 550°C). Os tempos de exposição a elevadas temperaturas, após homogeneização térmica do material, foram de 0 (padrão), 60 e 90 minutos. As amostras com o maior percentual de molibdênio (0,27% em peso) apresentaram melhores propriedades mecânicas para as condições de elevada temperatura. À temperatura ambiente, o material com grafita refinada teve valores de resistência à tração mais elevados em relação aos outros dois materiais. As propriedades mecânicas de microdureza, tensão de escoamento 0,2% e deformação específica complementaram a análise do comportamento destas propriedades à elevada temperatura. De acordo com os resultados obtidos, a redução na resistência mecânica com a elevação da temperatura é atribuída à ocorrência de decomposição da perlita, como resultado da difusão do carbono vindo da cementita migrando à grafita, que é o responsável pelo aumento da quantidade de grafita no material. As análises metalográficas evidenciaram a ocorrência deste fenômeno. Aumentos no tempo de exposição a temperaturas elevadas também contribuíram para a degeneração da perlita. Toda avaliação microestrutural se deu por análise de percentuais 14 de grafita, cementita e tamanho da grafita a diferentes temperaturas de ensaio, bem como diferentes tempos de exposição à elevada temperatura.

The work deals with the development of a new thermal insulation material that contains a secondary raw materials or waste. It is an insulating material with the requirement of resistance to high temperatures - 200 ° C and 500 ° C. Type of material is determined by the way of reducing density - direct and indirect. Direct is achieved by adding lightweight aggregates, indirect is achieved by gas evolution through chemical reaction and the subsequent incorporation of gas into the structure of the material. This thesis is part of the MPO TIP č. FR-TI 2/340 project.

Tagebaumaßnahmen führen durch Entfernung des Oberbodens, Vermischung von Bodenschichten bei der Wiederverfüllung von Restlöchern und Maschineneinsatz dazu, dass auf Tagebaufolgeflächen meist extrem schwierige Standortbedingungen für Pflanzenwachstum herrschen. Dazu zählen v.a. Bodenverdichtung und Bodenversauerung durch die Verwitterung von Eisensulfiden, was Ernährungsstörungen und Belastungen mit Schwermetallen und anderen Schadstoffen zur Folge hat. Die Bodenbedingungen sind auf kleinem Raum sehr heterogen. Das ungünstige Mikroklima der vegetationsfreien Flächen verstärkt die durch Bodenverdichtung schwierige Wasserversorgung. Mykorrhiza-Pilze fehlen oft zunächst. Ziel dieser Arbeit war die Entwicklung eines möglichst wenig aufwendigen Konzeptes, um mit Hilfe geeigneter Baumarten und Bodenhilfsstoffe zumindest auf kleiner Fläche eine Begrünung von Kippen-Rohböden zu erreichen, um so Startpunkte einer Sukzession zu etablieren. Zu diesem Zweck wurden verschiedene Baumarten (Quercus robur, Acer platanoides, Sorbus aucuparia, Alnus glutinosa, Pseudostuga menziesii und Pinus sylvestris) und Bodenhilfsstoffe zur Verbesserung der physikalischen (Perlit, Wasserspeichersubstanzen: sowohl herkömmliches, petrochemisches Hydrogel als auch neuartiger Superabsorber aus pflanzlicher Stärke), chemischen (Kalk), physikalischen und chemischen (Kompost) sowie biologischen (Mykorrhiza-Impfung) Bodeneigenschaften getestet. Die Bodenhilfsstoffe wurden einzeln und miteinander kombiniert eingesetzt. Auf auch Jahre nach der Ablagerung des Haldensubstrats noch vegetationsfreien Flächen im ehemaligen Ronneburger Uranerz-Abbaugebiet wurden Freilandversuche mit knapp 1.000 Bäumen angelegt; Topfversuche im Gewächshaus dienten der Begleitung und Vertiefung. Die physikalischen und chemischen Bodeneigenschaften der Versuchsflächen wurden analysiert, die Effekte der Bodenhilfsstoffe darauf im Topfversuch überprüft. Die Entwicklung der Versuchspflanzen wurde über zwei Jahre hinweg durch regelmäßige Vitalitätsschätzungen auf einer 5-stufigen Skala, Messungen verschiedener Wuchsparameter und Analysen der Elementgehalte in den Assimilationsorganen untersucht. Die Böden wiesen eine sehr geringe Wasserspeicherkapazität und eine stark gestörte Infiltrations- und Wasserleitfähigkeit auf. Das Nährstoffpotential war mit Ausnahme sehr geringer Stickstoff-Gehalte gut. Eine sehr starke Versauerung sowie stark belastende Kupfer- und Schwefel-Gehalte waren die Haupt-Probleme. Auffällig waren hohe Magnesium-Gehalte und -Sättigungen. Die Versuchspflanzen waren entsprechend sehr stark mit Schwefel und Kupfer sowie mit Eisen, Aluminium und teilweise Mangan belastet und zeigten auffallend hohe Magnesium-Gehalte. Sie wiesen Ernährungsdefizite auf, die auf die geringe Stickstoffversorgung, Nährstoffantagonismen/Ionenkonkurrenz und Toxizität zurückgeführt werden können. Im Verlauf des Versuchs entwickelte sich auf einigen Versuchsflächen in Teilbereichen Spontanvegetation (Moose, Calamagrostis epigejos). Bodenuntersuchungen ergaben leicht höhere pH-Werte und eine entsprechend günstigere Ernährungssituation in diesen Bereichen, vermutlich aufgrund einer unregelmäßigen Flächenkalkung einige Jahre vor Versuchsbeginn. Die Entwicklung der Versuchspflanzen wurde stark von den Standortunterschieden beeinflusst. Kalk und Kompost hatten deutlich positive Effekte auf die chemischen Bodenbedingungen und die Pflanzenentwicklung. Mit Kompost war der Einfluss vor allem bei den anspruchsloseren Baumarten Eberesche, Schwarz-Erle und Wald-Kiefer oft größer. Daneben zeigten Mykorrhiza-Impfungen eine starke Wirkung, vor allem in Kombination mit Kalk und/oder Wasserspeichersubstanzen. Die positiven Wirkungssynergismen von Mykorrhiza-Impfungen und Wasserspeichersubstanzen auch ohne Kalk-Gaben waren angesichts der sehr stark sauren Standortverhältnisse bemerkenswert. Darüber hinaus hatten Wasserspeichersubstanzen wie auch Perlit keine, teilweise sogar negative Effekte durch Herabsetzung der Kalk-Wirkung in kombinierten Varianten. Zudem wiesen die mit Perlit oder Wasserspeichersubstanzen gepflanzten Bäume teils hohe Schadstoff-Belastungen auf. Die Bodeneigenschaften wurden nicht beeinflusst; die feinbodenreichen Lehmböden mit ihrer geringen Infiltrationsfähigkeit durch Zerscherung der Grobporen bei Verdichtung schienen für den Einsatz von Wasserspeichersubstanzen weniger geeignet zu sein. Das Vorhandensein von Pilz-Partnern zur Mykorrhiza-Bildung ist auf diesen schwierigen Standorten offenbar von besonderer Bedeutung, da diese Symbiose die Wasserversorgung von Pflanzen verbessern kann, außerdem ihre Ernährung fördert und die Schadstoff-Aufnahme hemmt, wie im Rahmen der vorliegenden Arbeit bestätigt werden konnte. So konnten durch kombinierte Mykorrhiza-Impfungen teilweise selbst die extremen Schwefel-Gehalte auf ein normales Maß gesenkt werden, was mit Kalkung allein nicht der Fall war. Die obligat Mykorrhiza bildenden Rot-Eichen und Wald-Kiefern, zwei eigentlich zur Tagebaurekultivierung sehr geeignete und viel verwendete Baumarten, zeigten insgesamt hohe Ausfallraten. Bei den Eichen spielte dabei die schlechte Qualität des Pflanzenmaterials, bei den Kiefern wahrscheinlich starke Trockenheit zum Zeitpunkt der Versuchsanlage im Frühjahr 2005 eine Rolle. Bei den ebenfalls obligat Mykorrhiza bildenden Douglasien war der Standort in günstigeren Bereichen, in denen sich auch Spontanvegetation entwickeln konnte und in die nachweislich Mykorrhiza-Pilze einwanderten, von großer Bedeutung. Wie die als einzige Baumart nicht mit Kupfer belastete Eberesche und die durch ihre Symbiose mit Stickstoff-fixierenden Bakterien sehr gut geeignete Erle, die von allen Baumarten die besten Ergebnisse zeigte, konnte sich auch die Douglasie auf diesen etwas besseren Standorten selbst ohne Bodenhilfsstoffe zufrieden stellend entwickeln. Angesichts des extremen Sommers 2006 kam vermutlich auch ihre Trockenheitstoleranz zum Tragen. Die Spitz-Ahorne zeigten hohe Schadstoff-Belastungen, kaum Wachstum und eine stark gestörte Wurzel-Ausformung. Die Baumart wurde zudem stark verbissen und erwies sich insgesamt als wenig geeignet. Auf Grundlage der Ergebnisse der auf den Ronneburger Tagebaufolgeflächen durchgeführten Untersuchungen wird für die Rekultivierung dieser und vergleichbarer Standorte eine Mischung aus Erlen, Ebereschen und Douglasien empfohlen, wobei die Erle auch aufgrund ihrer Standort verbessernden Eigenschaften den größten Anteil einnehmen sollte. In stärker versauerten (pH KCl < 4), frei von Bodenvegetation bleibenden Bereichen sollte einige Zeit im Vorfeld der Pflanzungen eine Kalkung mit aufgrund der Bodengehalte magnesiumfreiem Kalk erfolgen, um die Voraussetzungen für Bodenvegetation und Mykorrhiza-Pilze zu verbessern. Bei den Ebereschen und Erlen ist eine Kompost-Gabe ins Pflanzloch als Starthilfe sinnvoll. Zumindest bei den Douglasien sollten Mykorrhiza-Impfungen durchgeführt werden, die generell auf diesen Standorten empfehlenswert sind und somit auch für die Ebereschen und Erlen sehr vorteilhaft sein können. Die Dauer der Wirkung der Bodenhilfsstoffe und die über die beobachtete Zeit hinaus gehende Entwicklung der Bäume sind unter den gegebenen, sehr schwierigen Standortbedingungen mit fortschreitender Pyrit-Verwitterung und damit Bodenversauerung offen.

L’industrie automobile cherche constamment à augmenter la part des pièces fabriquées à partir de tôles minces en aciers plus résistants et à plus bas coût. Le parallèle entre les diagrammes de phases Fe-N et Fe-C montre qu’il est possible de développer des aciers similaires dans le système Fe-N. Les objectifs de cette étude étaient l’élaboration des aciers binaires Fe-N et le développement des structures équivalentes à celles dans les aciers au carbone. Les approches envisagées s’articulent autour de : Elaboration : la nitruration gazeuse en phase austénitique suivie de traitements d’homogénéisation ont permis de charger des tôles minces de fer pur en concentrations importantes d’azote. Une simulation de la diffusion de l’azote a été proposée. Genèse des microstructures : Le refroidissement lent de l’austénite Fe-N conduit à des structures perlitiques lamellaires et globulaires, constituées de ferrite et du nitrure non-stoechiométrique Fe4N. Une structure aciculaire particulière a été identifiée. Il s’agit de la ferrite se développant dans le nitrure Fe4N. Le refroidissement lent de la ferrite Fe-N sursaturée conduit à la précipitation des nitrures stables Fe4N et métastable Fe16N2. Des microstructures multiphasées [alpha+alpha'+gamma] ont été obtenues par des maintiens dans le domaine intercritique suivis de trempe. Le domaine intercritique a été réexaminé en utilisant le modèle des sous-réseaux. Des essais in-situ en MET ont relevé l’évolution des précipités de Fe16N2 dans la ferrite au cours du vieillissement à 85 °C. Des proportions importantes de l’austénite résiduelle ont été relevées, ce qui serait à la base du développement des aciers TRIP à l’azote / Car designers are seeking ways to increase the proportion of parts made of sheet steels of higher strength and lower cost. The parallel between the Fe-N and Fe-C phase diagrams shows that it is possible to develop similar steels in the Fe-N system. The objective of this study was to prepare binary Fe-N steels and to develop structures equivalent to those in carbon steels. Approaches to meet the objectives are considered: Preparations of Fe-N steels: gas nitriding in austenite domain followed by homogenization treatments allowed to introduce high amount of nitrogen in pure iron sheet. A simulation of the nitrogen diffusion was proposed to describe the weight increase during nitriding. Genesis of microstructures: The slow cooling of the Fe-N austenite led to lamellar and globular pearlitic structures composed of ferrite and nitrideFe4N. An acicular microstructure, which is the consequence of the precipitation of the ferrite in the nitride Fe4N, was also identified. The slow cooling of the supersaturated Fe-N ferrite led to the precipitation of the stable nitride Fe4N and the metastable nitride Fe16N2, which witnessed a rapid diffusion of nitrogen in ferrite at low temperature, comparable to that of carbon. The multiphase microstructures [alpha+alpha'+gamma] were obtained by intercritical treatments followed by quenching. The intercritical domain was reviewed using the sub-lattice model. In-situ TEM investigations have identified the precipitation of Fe16N2 nitride in the ferrite during the aging at 85 °C. High amount of the residual austenite have been identified, which would be the basis for development of TRIP nitrogen steels

The diploma thesis is focused on the verification of the parameters of thin lightweight mineral plasters with modified composition. As alternative raw materials are used expanded perlite Vapex, calcined diatomite Celite and powder waste glass of fluorescent lamps. In the theoretical part is summarized knowledge from completed studies dealing with the issue of compensation porous filler component. In the experimental part is tested consistency of fresh mixture, physical-mechanical, sorption and thermal insulating characteristics. It is compared the appearance of the surface and summarized the results of measuring.