Clinker Portland with iron ore tailing and its characterization by integrated laboratory methods

Abstract

The large volume accumulation of iron ore tailings (IOT) in Brazil poses significant risks of accidents, highlighting the need for strategies for their recycling. The Brazilian's IOT possesses mainly iron oxide content (HI-IOT) and can be used as raw materials alternatives in clinker production. Based on a fixed lime saturation factor (LSF = 0.96), we incorporated 5 to 10 wt% of HI-IOT in the raw meal to produce Portland clinkers. The mineralogical phases (alite, belite, aluminate, and ferrite) were evaluated by quantitative X-ray diffraction. Optimal results were obtained with 7.5 wt% of HI-IOT in the clinker Portland, i.e., approximately 32 %wt. of clay substitution. The mechanical strength evolution was evaluated by a reduced-size test and obtained compressive strength of 34.8 MPa at 3 days-age, 54.10 MPa at 7 days-age, and 71.20 MPa at 28-days values compatible with standardized high initial strength Portland cement. By monitoring the complete hydration process using TG/DTG and assessing the volumetric composition over time, valuable insights were gained regarding the potential application of these Portland cements at an industrial scale.