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Fragmentação de materiais rochosos: análise e influência de parâmetros que interferem no consumo energético e na geometria dos produtos finais
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Abstract(s)
O processo de fragmentação, numa instalação de britagem, consiste em reduzir os materiais rochosos em partículas de menores dimensões, com recurso à utilização dos fragmentadores. Como as rochas não apresentam características petrográficas e mineralógicas iguais, quando sujeitas a forças externas provocadas pelos fragmentadores, não se fragmentam de forma idêntica.
De forma a comprovar estas afirmações, o estudo objeto desta dissertação baseou-se nessa análise. Numa primeira parte foram abordados temas ligados à redução de calibre processada pelos fragmentadores e mecanismos de fragmentação, assim, como parâmetros que influenciam a forma do produto. Com vista à identificação dos parâmetros geométricos, físicos e mecânicos que interferem na fragmentação dos materiais rochosos, concretizaram-se ensaios laboratoriais. Foram analisadas as propriedades de quatro amostras de litologias diferentes: duas de granito (pedreira de Fornelo e Serdedelo) e duas de calcário (pedreira de Sangardão e Vale Grande n°2). Após o tratamento dos dados laboratoriais, realizou-se uma interpretação estatística das variáveis analisadas nos ensaios, com vista a relaciona-las com o índice de fragmentabilidade.
Na produção de rochas industriais, a operação de fragmentação é a que acarreta maior consumo de energia.
Por isso, numa última abordagem, elaborou-se uma análise do consumo energético na etapa de fragmentação onde foram recolhidas as amostras em estudo. Para determinar a energia específica desse estágio, recorreu-se à aplicação da fórmula de Bond.
Perante os resultados obtidos, concluiu-se que as propriedades dos materiais rochosos, como textura, dureza dos minerais, grau de alteração, resistência e a sua constituição são parâmetros que interferem na redução das partículas na fragmentação. No processo de fragmentação na instalação de britagem, a geometria do produto depende do fragmentador utilizado. Quanto ao consumo energético, está parcialmente dependente do tipo de fragmentador e da sua abertura de saída, assim como, o tamanho da alimentação.
The fragmentation process, in a crushing plant, consists on reducing the size of the rocky materials to small particles, using the so-called crushers. Since rocks do not have identical petrographic and mineral characteristics, when under the influence of external forces caused by the crushers, they will not break in the same way. In order to prove these claims, the dissertation was focused on this analysis. In the first part of this work the themes are related to the caliber reduction by the crushers and the crushing mechanisms, as well as, the parameters which influence the product’s shape. With the object to identify the geometrical, physical, and mechanical parameters of rock materials, laboratory tests were made. The properties of four different samples were analyzed: two samples of granite (Fornelo and Serdedelo quarries) and two limestone samples (Sangardão and Vale Grande nº2 quarries). After data analysis, a statistical interpretation of the variable behavior in the tests was done, aiming to compare them with the crushability index. In the production of industrial rocks, the crushing operation is responsible for the higher energy consumption. Therefore, in a last effort, the energy consumption in the crushing step was evaluated on the place where the study samples were collected. To calculate the specific energy of this stage, the Bond formula was employed. With the results obtain previously, it was concluded that the properties of the rock materials, such as, texture, minerals hardness, degree of alteration, resistance and its constitution are parameters that interfere with the reduction of the particles in the fragmentation. In fragmentation process in the crushing plant, the geometry of the product depends of the utilized crusher. As for the energy consumption, it is partially dependent of the type of crusher and the opening of the exit, as well as, the size of the feed.
The fragmentation process, in a crushing plant, consists on reducing the size of the rocky materials to small particles, using the so-called crushers. Since rocks do not have identical petrographic and mineral characteristics, when under the influence of external forces caused by the crushers, they will not break in the same way. In order to prove these claims, the dissertation was focused on this analysis. In the first part of this work the themes are related to the caliber reduction by the crushers and the crushing mechanisms, as well as, the parameters which influence the product’s shape. With the object to identify the geometrical, physical, and mechanical parameters of rock materials, laboratory tests were made. The properties of four different samples were analyzed: two samples of granite (Fornelo and Serdedelo quarries) and two limestone samples (Sangardão and Vale Grande nº2 quarries). After data analysis, a statistical interpretation of the variable behavior in the tests was done, aiming to compare them with the crushability index. In the production of industrial rocks, the crushing operation is responsible for the higher energy consumption. Therefore, in a last effort, the energy consumption in the crushing step was evaluated on the place where the study samples were collected. To calculate the specific energy of this stage, the Bond formula was employed. With the results obtain previously, it was concluded that the properties of the rock materials, such as, texture, minerals hardness, degree of alteration, resistance and its constitution are parameters that interfere with the reduction of the particles in the fragmentation. In fragmentation process in the crushing plant, the geometry of the product depends of the utilized crusher. As for the energy consumption, it is partially dependent of the type of crusher and the opening of the exit, as well as, the size of the feed.
Description
Keywords
Agregados Consumo energético Geometria das partículas Índice de fragmentabilidade Aggregates Energy consumption Particles geometry Crushability index