Simulating blending of iron ore sinter feed in industrial stockpiles using a voxelization-based geometric model. Part I: Model development considering inter-batch variability

Abstract

Stockpiling is the most used method for buffering and homogenization of large volumes of bulk materials. Homogenization occurs due to the mixing action of stacking and reclaiming procedures but some variability in the material properties persists when it is finally fed to the process. Such variations may require corrections in the operational set-up of the process for maintaining the quality of the product. A specific case of interest takes place inside steelmaking facilities, where iron ore sinter feed is transformed into sinter product, after being mixed with additives. The chemical and physical properties of sinter feed used in a large steelmaker in Brazil present largevariations since the supplier relies on material from different production sites, which are delivered through multiple railroad compositions. The work presents the development of a tool for the simulation of the operations of stacking and reclaiming of sinter feed for the case in which the stockpile is fed by train compositions representing four to six batches. The tool aims to predict the time-dependent variations in the properties of sinter feed while being fed to the sintering process. The tool was specifically developed for the case of interest, restricted to the utilization of the Chevron stockpiling scheme and the reclaiming procedures used in the site. The idealization of the shape of the pile and the symmetry of the Chevron scheme allowed to optimize the numerical method and improve computation times substantially. The present work focuses on the effects of inter-batch variability, while the analysis of intra-batch variability and the extension to other stockpiling schemes will be the object of a second work in the series. The tool was implemented and validated using data from industrial surveys. Additional case studies were simulated to assess its capabilities and limitations. Results show that the tool can provide a reasonable estimate of the properties of sinter feed being fed to the process and that it is suitable to be used in planning raw materials yard operations.