Caracterização tecnológica de minério de níquel laterítico

Abstract

The object of this study is the technological characterization of saprolitic lateritic ore from the Barro Alto deposit, Goiás. Practical observations within CODEMIN’s RKEF (Rotary Kiln Electric Furnace) circuit, owned by Anglo American, demonstrated variations in its performance even when ore piles with equivalent chemical composition are fed into it. These variations were previously attributed to the difference in mineralogical composition. In this context, in order to perform an evaluation combining the chemical and mineralogical composition with the operational performance of the CODEMIN’s RKEF circuit, a technological characterization was proposed. The characterization was performed for ten representative samples which were taken from ten different ore stockpiles that fed the CODEMIN’s RKEF circuit. For each sample chemical analysis were performed using x-ray fluorescence (XRF); mineralogical analysis using x-ray diffraction (XRD); and thermal analysis using thermogravimetry (TG / DTG) and differential thermal analysis (DTA). Also, the industrial data was analyzed in order to determine a quantification performance model and a predictability model for pre reduction. The results indicated that for the analyzed samples, the vermiculite, chromite, goethite and clinochlore can contribute negatively to the performance of the main monitoring and process control parameters as well as the proportion of amorphous together with clinochlore and goethite phases may help to predict the pre-reduction during calcining. It was also found that the model to quantify the performance was considered satisfactory for the analyzed data.