Predição do fluxo de bentonita em silos verticais.

Abstract

Brazil is ranked as highest for its great world reserves of a diverse group of metallic and non-metallic minerals pointing out as one of the six most important mineral countries in the world. Industrial minerals such as bentonite represent a great deal in the sum of the mineral goods produced in Brazil. Storage silos play a very important role at industrial processes, especially in the areas of mineration and agrarian industry, serving as means of storage and manipulation at production processes. In some countries researches in this area are applied through technical norms for the calculation of silos. The number of researches in the area is still very limited and that is proved by the fact that Brazil does not have a specific norm for " Actions and flow in silos" , which could guide projects and professionals connected to the field even though it is one of the principal producers of minerals in the world, thus causing several problems related to silo projects at mineral products processing industries. The present work had the objective to determine the physical and flowing properties of bentonite so they can be used for silos dimensioning. Tests were performed with the TSG 70-140 machine known as " Jenike Shear Cell" presenting the following properties: humidity level, granulometry, consolidated density, angle of internal friction, effective angle of internal friction, wall friction angle, flow function and flow factor. Made adjustments being obtained define equations that were adequate for the experimental results. An analysis was also applied at the kind of flow occurred at prismatic silos with eccentrical discharge for two kinds of discharge transversal sections and two kinds of storage time. Average runoff discharge was finally determined. The discharge holes used in the experiment were able to guarantee mass flow without the occurrence of cohesive arches. The properties determined in the experiment can be inserted at a future Brazilian norm actions and flow in silos.