Procedimentos experimentais para avaliação da emissão de poeira em manuseio de minério

Abstract

The generation of dust during the handling and transportation of bulk causes a series of problems, such as the erected air and loss of valuable material. Due to the risk associated with inhalation of dust, several control mechanisms have been adopted. The use of water is a viable option to inhibit the generation of dust, although the use of chemical suppressants is in some cases more appropriate. However, standards and methods for characterizing the generation of particulates are not very consolidated in the literature, for the proper selection of the control mechanism. Therefore, this study aimed to develop test methodologies to evaluate the emission of minerals particulate. The emission of particulate during transport was evaluated in a test bench developed by adapting an existing wind tunnel, using a wagon model and air speeds of 40 km/h and 70 km/h, for different iron ore moisture values. Results show that the increase in flow speed increases the loss of material mass contained inside the wagon model and the increase in material moisture significantly reduces the loss of mass, being enhanced with the use of dust suppressants applied to the material surface. To simulate material handling, a bench was developed using the dust tower technique concept, which allows dust generation tests during material discharge. In the results obtained, it is also verified that the increase in material moisture significantly reduces the emission of particulates, being more evident for materials that have a higher percentage of fines. The influence of suppressants was also evaluated, and among the tested reagents Fe2(SO4)3 showed the best result for the pellet feed milled, greatly reducing the emission of particulates in relation to the use of water only. For pellets, Ca(OH)2 showed the best results without curing time and CaCl2 for the condition with curing time of 2 hours. Therefore, the results show that the benches and experimental procedures developed, presented satisfactory and coherent results, which are reliable for the characterization of the emission of particulates from different materials.