Potencial da utilização de rejeito de minério de um ferro como precursor no desenvolvimento de um ligante álcali-ativado

Abstract

Iron ore production grows every year, along with the positive economic percentage that this sector brings to the country's economy. On the other hand, geotechnical challenges also increase for mining. Responsible for major environmental disasters that have occurred in recent years, this sector needs alternatives that seek to solve the large demand for waste from the ore beneficiation process and which is disposed of in dams. Therefore, this work proposed the development of an activated alkali binder from iron ore waste. The proposed methodology is characterized by the use of iron ore waste as a precursor, the use of industrial waste carbide lime (CC) as a source of calcium, and sodium silicate (SS) as an activator. The curing was carried out for a period of 7 days at a temperature of 23°C to approximate room temperature. The tested samples were evaluated through simple compression strength and characterized by X-ray Diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and metal leaching. Three percentages of lime (5%, 7% and 10%) and five concentrations of activator (10%, 15%, 20%, 25% and 30%) were studied. As a result, the best simple compression strength was obtained at 277.44 kPa or 0.27 MPa, with the concentration of 10% CC and 20% SS, where it was possible to observe evidence of CASH and NASH gel formation. In addition, the samples did not present toxicity and metal leaching at levels higher than the normative parameters analyzed.