ESTUDIO DE VIABILIDAD DEL USO DE RESIDUOS DE MINERAL DE HIERRO COMO PIGMENTO EN RESINAS DE POLIPROPILENO

The Brazilian mining industry plays a significant role in the country’s economy. However, it also generates large volumes of waste during the ore beneficiation process, resulting in severe environmental impacts. Recent researches have explored the potential of iron ore tailings as a raw material in the manufacturing of construction materials, aiming to reduce environmental impact. The distinctive coloring acquired by the produced materials can contribute to their application in certain segments where aesthetic factors are relevant. This study aimed to evaluate the feasibility of iron ore tailings, derived from the dam breach in Mariana-MG, as a pigment for polypropylene, widely used as a polymer matrix for composites, especially wood-plastic composites. Samples with different polypropylene and iron ore tailing contents, ranging from 1 to 10 % by mass, were developed using thermokinetic mixing, milling, extrusion, pelletization and hot compression processes. The produced specimens were analyzed for their appearance and evaluated for their mechanical performance. The results showed that the tailings presented high pigmentation power when incorporated into polypropylene, without compromising its mechanical properties and even providing a gain in flexural strength. However, the proportion between the amount of residual material used and the total volume of waste discarded in nature is very low, indicating limited potential for material reuse. This situation can be modified by using the tailings in the production of woodplastic composites, where, in addition to acting as pigment, they can also act as reinforcing filer. This approach would allow the utilization of a considerable larger portion of the residual material.