Avaliação ambiental para o aproveitamento de rejeito de minério de ferro: estratégia para redução de disposição de rejeitos em barragens de contenção e redução dos riscos aos recursos hídricos

Abstract

Results to recent ruptures of iron ore tailings dams in Brazil, there was an intensification of the need to propose alternatives for the use of these structures using especially to increase water security, to preserve natural and human resources. In this context, the present study has the objective to evaluate the environmental use of iron ore flotation tailings as a material consisting of road pavements; as a strategy to reduce risks to water resources. Iron ore tailings samples, collected continuously at the output of the flotation duct of the Cauê-Itabira/MG mine, were subjected to leaching tests and solubilization tests according to current regulatory procedures. Specimens made by simulating the composition of road pavements, evaluating 6 (six) possibilities according to different compositions and different layers on the pavement structure, were subjected to the same tests. The results indicated the iron ore tailings are classified as class IIA waste Not dangerous-Not inert, considering that the manganese and phenols elements had solubilized percentege above that allowed by legislation. The results to the tests on the pavement samples indicated the specimens made with Soil/Iron ore tailings/Lime and Soil/Iron ore tailings/Cement were the most efficient in retaining the manganese and phenols elements, being, therefore, the most viable for the use of the waste from the environmental point of view. However, as the aluminum content has exceeded the limits of the norm, due to the pH increase in these samples, it is recommended to reduce the lime and cement content, trying to keep the pH below 9.0. To ensure immobilization of the contaminating elements, it is recommended to do studies on adsorption and incorporation of polymers (adsorbent materials) on the pavements.