The literature concerning the injection moulding of engineering ceramics has been reviewed. This indicated that a number of claims had been made for the successful use of different organic binders during moulding and their removal prior to sintering. However, many of the claims were not supported by detailed/exact eScperimental evidence as to powder-binder compositions, moulding conditions, moulded properties, debinding times/cycles, or details of the structure and properties of the solid ceramic bodies produced. From the available information it was clear that there were few systematic and scientific investigations concerning the understanding of each stage of the injection moulding process. The present research programme has been carried out in two phases as follows. The first phase was concerned with the reinvestigation and re-evaluation of binder systems claimed to be successful for the injection moulding of alumina ceramics. The binders re-investigated included the thermoplastic-based binders such as polystyrene, polyacetal and atactic polypropylene and the water-based methylcellulose (Rivers) binder system. Alumina was chosen as the main powder to be investigated due to its simple handling and, highest applications amongst ceramic materials and on the basis that there is incomplete published work for almost every step of the injection moulding process. During the first stage of this work the optimum properties such as powder-binder compositions, mixing and moulding conditions, debinding properties, green and sintered densities provided by each binder system were determined. The results of these investigations showed that all the previous (re-evaluated) binder systems had major limitations and disadvantages. These included low volume loading (64 % maximum) of the alumina powder resulting in rather low sintered densities (96 % maximum-of theoretical density) and very long debinding times in the case of the thermoplastic-based binders. it ry low alumina volume loading (55 % maximum resulting in a 94 % . sintered theoretical density) and long moulding cycle time (- 5 min) along with adhesion and distortion problems during demoulding occurred in the case of the water-based methylcellulose binder system. Further work did not appear worthwhile. The newly developed binder systems have been used with a number of other powders such as zirconia, silicon nitride, silicon carbide, tungsten carbide-6 weight % cobalt and iron-2 weight % nickel, to establish- whether injection moulding is feasible. Optimum properties such as powder volume loadings, mixing, moulding, demoulding, moulded densities, debinding and some sintered density results showed that these new binder systems can also be used successfully for the injection moulding of other ceramic and metallic powders, although a fuller evaluation of the properties such as optimum sintered densities and mechanical properties is required.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-10-05T20:33:12Z No. of bitstreams: 2 Dissertação - Mariana Rezende de Barros - 2016.pdf: 5601059 bytes, checksum: 953996d14e3ede469126893d305e59ce (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-10-06T11:38:33Z (GMT) No. of bitstreams: 2 Dissertação - Mariana Rezende de Barros - 2016.pdf: 5601059 bytes, checksum: 953996d14e3ede469126893d305e59ce (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-06T11:38:33Z (GMT). No. of bitstreams: 2 Dissertação - Mariana Rezende de Barros - 2016.pdf: 5601059 bytes, checksum: 953996d14e3ede469126893d305e59ce (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-01 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Modern agriculture requires productivity, efficiency and quality. Therefore, there is need for the application of agricultural lime to correct the soil acidity. The Midwest was appointed as the largest producer of agricultural limestone, with 38.2% and Goiás and holder of 11.6%. In limestone beneficiation process is the generation of fine material (through in # 400 (0.035 mm)), which does not have economic viability in the agricultural, metallurgical and calcination. This is because this particle size of particle decreases the percolation of gas in blast furnaces and has slow settling when used in agriculture, can be transported by wind generating environmental liabilities. Briquetting is to agglomeration of fine particles by pressure, aided or not by a binder, allowing obtaining not only compacts, but with size, shape and mechanical parameters. The objective of this study was to investigate the binding of fine limestone through briquetting through use of a specific type known to have very fine grained (<0.075 mm) using organic and inorganic binders. Agglomeration of fine limestone through the briquetting was conducted by varying the amounts of water (used as inorganic binding agent) 0; 5; 7.5; 10; 12.5% and 2.5; 5; 7.5 and 8.5% organic binders - Molasses Soy and Treacle of cane sugar. The limestone powder and briquettes were analyzed chemically and physically by Scanning Electron Microscopy, Energy Dispersive X-ray (EDS), chemical and particle size analysis. The briquettes were subjected to impact resistance test, resistance to breakdown in water and compressive strength. The best results in impact resistance tests were analyzed and from these results of other tests were performed. The results of mechanical impact resistance were analyzed statistically by analysis of variance (ANOVA), checking if the binder content and factors influenced the agglomeration of the mineral. In addition to lowering the environmental liabilities, the briquettes will also generate profits for the mining industry and can offer a co-product with similar characteristics to the product originally marketed. / A agricultura moderna exige produtividade, eficiência e qualidade. Por isso, há necessidade da aplicação do calcário agrícola para corrigir a acidez dos solos. O Centro- Oeste foi apontado como o maior produtor de calcário agrícola, com 38,2% e Goiás sendo detentor de 11,6%. No processo de beneficiamento do calcário ocorre a geração de material fino (passante em 400# (0,035 mm)), que não possui viabilidade econômica nos setores agrícola, metalúrgico e de calcinação. Isso ocorre porque essa granulometria de partícula diminui a percolação de gases nos altos-fornos e possui sedimentação lenta quando empregada na agricultura, podendo ser transportada pelo vento gerando passivo ambiental. A briquetagem consiste na aglomeração de partículas finas através de pressão, auxiliada ou não por aglutinantes, permitindo obtenção de produtos não só compactados, porém com forma, tamanho e parâmetros mecânicos. O objetivo do trabalho foi verificar a aglomeração dos finos de calcário por meio da briquetagem através aproveitamento de um tipo específico conhecido por possuir granulometria bastante fina (< 0,075 mm) utilizando aglomerantes orgânicos e inorgânicos. A aglomeração dos finos de calcário através da briquetagem, foi realizada variando as dosagens de água (utilizada como agente aglomerante inorgânico) de 0; 5; 7,5; 10; 12,5% e 2,5; 5; 7,5 e 8,5% de aglomerantes orgânicos – Melaço de Soja e Melado de Cana-de-açúcar. O calcário em pó e os briquetes foram analisados química e fisicamente por meio de Microscopia Eletrônica de Varredura, Energia Dispersiva de Raios-X (EDS), análises química e granulométrica. Os briquetes foram submetidos a testes de resistência ao impacto, resistência à decomposição em água e resistência a compressão. Os melhores resultados obtidos no teste de resistência ao impacto foram analisados e a partir desses resultados foram realizados os demais testes. Os resultados de resistência mecânica ao impacto foram analisados estatisticamente através da análise de variância (ANOVA), verificando se os fatores aglomerantes e teor influenciaram na aglomeração do mineral. Além de diminuir o passivo ambiental, os briquetes também irão gerar lucros para a indústria mineral, podendo oferecer um coproduto com características semelhantes ao produto originalmente comercializado.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-13T19:56:21Z No. of bitstreams: 1 FRANCISCO PINTO FILHO – TESE (PPGEP) 2016.pdf: 2405186 bytes, checksum: d7b5b1d68600f138fc5134159b39d6fc (MD5) / Made available in DSpace on 2018-06-13T19:56:21Z (GMT). No. of bitstreams: 1 FRANCISCO PINTO FILHO – TESE (PPGEP) 2016.pdf: 2405186 bytes, checksum: d7b5b1d68600f138fc5134159b39d6fc (MD5) Previous issue date: 2016-08-29 / Capes / A busca por inovações tecnológicas nos últimos anos cada vez mais se intensifica. Neste contexto, dois importantes grupos, os lantanídeos e as hidantoínas se destacam com importantes contribuições em diversas áreas de pesquisas apresentando vasto campo de aplicações. Nesses termos, esta pesquisa teve como objetivo sintetizar e caracterizar nanocomplexos dos íons lantanídicos: Eu +3, Er+3 e Nd+3 com 5-(4-metilfenil)-3-fenil-2-tioxo-imidazolidin-4-ona (HPA) e um segundo ligante, 1,10-fenatrolina (Phen), almejando obter complexos com propriedades biológicas. Partindo da reação entre os cloretos dos respectivos lantanídeos com os ligantes orgânicos, sob refluxo de aproximadamente 8 horas e temperatura de 60°C, foram obtidos os complexos de európio, érbio e neodímio. Os nanocomplexos em pó foram caracterizados utilizando técnicas de análises espectroscópicas, térmicas e estrutural. Os complexos de íons lantanídicos apresentaram resultados da análise elementar conforme a estequiometria proposta (1:3:1). A coordenação dos ligantes com os íons lantanídicos ocorreu através dos átomos de oxi gênio e enxofre da estrutura do 5-(4-metilfenil)-3-fenil-2-tioxo-imidazolidin-4-ona (HPA) e dos átomos de nitrogênio (C=N) da 1,10’- fenantrolina, que podem ser observados nos espectros de infravermelho, através dos deslocamentos dessas bandas presentes nos ligantes livres e coordenados. Os espectros UV-Vis apresentaram discretos deslocamentos e mudanças nas intensidades das bandas de absorção dos complexos em relação ao ligante HPA. As curvas TG/DTG do ligante HPA apresentou 3 etapas de decomposição, enquanto, que os complexos apresentaram 4 etapas. O nanocomplexo de Eu+3 apresentou menor estabilidade térmica, o que possibilita o uso destes pós como fármacos. As curvas DSC dos nanocomplexos apresentaram uma série de eventos endotérmicos e exotérmicos correspondentes a processos de decomposição, desidratação, fusão e volatilização que corroboram com as curvas termogravimétricas. Todos os complexos lantanídicos obtidos apresentaram dimensões nanométricas, e o complexo de neodímio apresentou a estrutura mais cristalina. / The search for technological innovations in recent years increasingly intensifies. In this context, two major groups, the lanthanides and hydantoins stand out with important contributions in many areas of research showing wide field of applications. In these terms, this research aims to synthesize and characterize complex of lanthanide ions: Eu+3, Ho+3, Er+3 and Nd+3 with 5-(4-methyl-phenyl)-3-phenyl-2-thioxo-imidazolidin-4-one (HPA) and a second linker, 1,10-fenatrolina (Phen), aiming to obtain complexes with biological properties. From the reaction between the chlorides of lanthanides with the respective organic ligands under reflux for approximately 8 hours and 60°C, were obtained complexes of europium, holmium, erbium and neodymium. The powder complexes were characterized using spectroscopic techniques, thermal and structural analyzes. The complexes of lanthanide ions showed elemental analysis results according to the proposed stoichiometry (1:3:1). The coordination of the ligands with lanthanide ions occurred through oxygen and sulfur atoms in the structure of 5 - (4-methylphenyl) -3-phenyl-2-thioxo-imidazolidin-4-one (HPA) and nitrogen atoms (C = N) of 1,10'- phenanthroline, which can be observed in the infrared spectra, through the displacement of these bands present in free and coordinated ligands. UV-Vis spectra showed discrete displacements and changes in the intensities of the absorption bands of the complex compared to the HPA binder. The TG/ DTG curves HPA binder 3 had decomposition steps, while the complexes showed 4 and 5 steps. The complex synthesized Er+3 showed higher thermal stability. The DSC curves of the complexes showed a series of endothermic and exothermic events corresponding to decomposition processes, dehydration, fusion and volatilization, corroborating the thermogravimetric curves. All lanthanide complexes obtained showed nanometric dimensions, and neodymium complex presented the most crystalline structure.