Establishing a Novel Methodology to Correlate the Macroscopic and Microscopic Degree of Sintering in Magnetite Pellets during Induration

Abstract

The quality of product pellets is a result of the physico-chemical phenomena involved in the induration process. Sintering is the primary phenomenon, and its degree or extent contributes substantially to the evolution of the metallurgical and mechanical properties of a pellet. During the induration of magnetite pellets, sintering proceeds through the oxidized and non-oxidized magnetite phases. Sintering of these phases has been previously studied on a single pellet at the macroscopic scale using an optical dilatometer. A deeper understanding requires corroboration of these studies through characterization at the microscopic scale. In the present work, the observations recorded at the microscopic scale are quantified using image processing techniques to correlate them to the macroscopic measurements. Distance transformation, which is an image processing principle, is adapted in a novel way to digitize the microstructures and to determine the degree of sintering in a pellet quantitatively. This methodology has potential applications as a generic tool to follow the sintering phenomenon and process kinetics at any stage during induration. Figure 7. Comparison of sintering degrees from the optical microstructures (microscopic) and optical dilatometry (macroscopic) for a) oxidized magnetite and b) non-oxidized magnetite pellets. www.advancedsciencenews.com www.steel-research.de steel research int. 2018, 89, 1700366

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