Artigos Científicos - ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/3360
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Item Acesso aberto (Open Access) Efeito de aditivos no comportamento reológico do rejeito da bauxita(Universidade Federal do Pará, 2015-03) GONÇALVES, Silvane Gonçalves e; BRUM, Sebastião Martins; FELIPE, Augusta Maria Paulain Ferreira; SOUZA, José Antônio da Silva; FERREIRA, Keylla CastroIn the bauxite mining in Parogominas, PA, Brazil, tailings are discarded in the processing with 33.5% of solids content and small particle size with D50 below 5 µm. These factors contribute to this suspension basically formed by silicoaluminates, with high concentrations of kaolinite clay, increase the viscosity and the yield stress, these factors are important during the pumping. It was performed granulometric analysis and determined the chemical and mineralogical composition of the material. It was studied the use of the sodium hexametaphosphate and polyacrylamide 25% anionic to decrease the viscosity. The result show that the viscosity decrease with use of 23.8 g/ton for the polyacrylamide and 101.75 g/ton for the sodium hexametaphosphate. The particle size and the pH have influence in the behavior of the additives.Item Acesso aberto (Open Access) Estudo da sinterização em reator vertical de leito fixo para produção de agregado sintético(Universidade Federal do Pará, 2017-06) QUARESMA, Danielly da Silva; NEVES, Alacid do Socorro Siqueira; MELO, Alvino Oliveira; PEREIRA, Luiz Felipe Silva; BEZERRA, Pamela Tais Silva; MACÊDO, Emanuel Negrão; SOUZA, José Antônio da SilvaThe synthetic aggregates are being employed in civil construction for the reduction of mineral extraction activities. Within this context, the recycling of industrial waste is the basis of the majority of processes to reduce the exploitation of mineral resources. In this work the sintering in a vertical fixed bed reactor for synthetic aggregate production using 20% pellets and 80% charcoal was studied. The pellets were prepared from a mixture containing clay, charcoal and fly ash. Two experiments varying the speed of air sucking were carried out. The material produced was analyzed by X-ray diffraction, scanning electron microscopy, measures of their ceramic properties, and particle size analysis. The results showed that the solid-state reactions, during the sintering process, were efficient and the produced material was classified as coarse lightweight aggregate. The process is interesting for the sintering of aggregates, and can be controlled by composition, particle size, temperature gradient and gaseous flow.