BIDISPERSE MIXTURES OF SAND: EFFECTS OF GRANULOMETRY ON ITS PACKING AND FLOWABILITY

Autor: Baiao, Denise, Machado, Camila dos Santos, Condotta, Rodrigo
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: The Journal of Engineering and Exact Sciences, Vol 4, Iss 1, Pp 0117-0126 (2018)
The Journal of Engineering and Exact Sciences; Vol. 4 No. 1 (2018); 0117-0126
The Journal of Engineering and Exact Sciences; Vol. 4 Núm. 1 (2018); 0117-0126
The Journal of Engineering and Exact Sciences; v. 4 n. 1 (2018); 0117-0126
The Journal of Engineering and Exact Sciences
Universidade Federal de Viçosa (UFV)
instacron:UFV
ISSN: 2527-1075
Popis: The present work aims to evaluate the effect of granulometry (particle size and particle size distribution) on the manly physical properties of bidisperse bulk solids, such as bulk density, porosity, cohesion, compressibility and basic flow energy. Therefore, two groups of mixtures comprising commercial sands with different sizes were prepared. The first group (G1) consisted on adding two sort of fine quartz powder (particle undersize of 200 and 600 mesh) into commercial sand 50/60 (coarse). The second group (G2) was formulated adding commercial sand (80/100 and 50/60) added into coarse one (40/50). All mixtures were tested at static and dynamic conditions and at incipient transition (shear test). As result, it was observed higher interactions for smaller quartz’s particles that lead to form agglomerates, increasing bulk porosity and reducing bulk density of non-consolidated mixtures comprising this sort of material. Fine particles at group 1 mixtures have also improved the quality of fluidization, but decrease powder flowability increasing cohesion. The results obtained for group 2 mixtures have revealed no significant changes on bulk properties as increasing fine particle into coarse one. This is could be attributed to the low ratio between fine and coarse particles, changing particle packing, once the interspaces between coarse particles could not be filled with fine one. Este trabalho teve como o objetivo avaliar o efeito da granulometria (tamanho das partículas e faixa de distribuição granulométrica) nas principais propriedades físicas de leitos bi dispersos, tais como densidade aparente, porosidade, coesão, compressibilidade e energia básica de fluxo. Para tanto foram confeccionados dois grupos de misturas envolvendo areias comerciais com diferentes granulometrias. O primeiro grupo (G1) consistiu na incorporação de dois tipos de areias de quartzo (partículas menores que mesh 200 e mesh 600) em um de tipo de areia de sílica comercial 50/60 (grosso). O segundo grupo (G2) constituiu em misturas de areias de sílica 40/50 (grosso) mediante adição de partículas de menor granulometria de areia de sílica 50/60 e 80/100. Todas as misturas foram analisadas em condições estáticas, dinâmicas e na iminência do movimento (cisalhamento). Como resultado observou-se uma maior tendência por parte das partículas de tamanho reduzido em formar aglomerados, aumentando a porosidade e diminuindo densidade aparente quando não consolidadas. A presença de partículas de tamanho reduzido nas misturas do grupo 1 também melhorou a fluidização das misturas deste grupo, mas prejudicou a fluidez aumentando a coesão do meio. Os resultados obtidos para o grupo 2 de misturas não apresentaram diferenças significativas em suas características com a incorporações de finos. Isto se deve a baixa relação entre o tamanho das partículas, de maneira que as partículas menores não cabem nos interstícios das partículas maiores.The present work aims to evaluate the effect of granulometry (particle size and particle size distribution) on the manly physical properties of bidisperse bulk solids, such as bulk density, porosity, cohesion, compressibility and basic flow energy. Therefore, two groups of mixtures comprising commercial sands with different sizes were prepared. The first group (G1) consisted on adding two sort of fine quartz powder (particle undersize of 200 and 600 mesh) into commercial sand 50/60 (coarse). The second group (G2) was formulated adding commercial sand (80/100 and 50/60) added into coarse one (40/50). All mixtures were tested at static and dynamic conditions and at incipient transition (shear test). As result, it was observed higher interactions for smaller quartz’s particles that lead to form agglomerates, increasing bulk porosity and reducing bulk density of non-consolidated mixtures comprising this sort of material. Fine particles at group 1 mixtures have also improved the quality of fluidization, but decrease powder flowability increasing cohesion. The results obtained for group 2 mixtures have revealed no significant changes on bulk properties as increasing fine particle into coarse one. This is could be attributed to the low ratio between fine and coarse particles, changing particle packing, once the interspaces between coarse particles could not be filled with fine one.
Databáze: OpenAIRE
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