Interactions between Magnetite Oxidation and Flux Calcination during Iron Ore Pellet Induration

Abstract

Many chemical reactions take place simultaneously during the induration of iron ore pellets produced from magnetite concentrates. Two of the most important are magnetite oxidation and calcination of carbonate fluxes. The first reaction consumes oxygen diffusing into the pellet, while the second reaction produces carbon dioxide that must diffuse out of the pellet. A mathematical model combining the two reactions and gaseous diffusion within the pellet has been developed to quantify the interaction between the two reactions. This combined mathematical model showed that current induration plant mathematical models for the mass and energy balance around a pellet furnace are inaccurate in treating magnetite oxidation and flux calcination as separate reactions. Assuming separate reactions can lead to an error of up to 20 pct conversion of magnetite at the end of the preheat stage. This combined mathematical model, confirmed by experiments with single pellets, also demonstrated that calcination of fluxes also tends to follow a ''shrinking core'' model rather than reacting simultaneously across the pellet, as existing whole plant models assume. Modifying induration plant mathematical models in accordance with the findings of this article could lead to further savings in energy costs for pellet plants.

Aquatic geochemistry of a major freshwater lake in the Kashmir Himalaya: solute acquisition and denudation process in the lacustrine system

“…Further, the significant negative correlation between SiO 2 and Fe 2 O 3 (R 2 = −0.53) content infers the presence of hematite and goethite in the form of silica/iron oxides and hydroxides in the lake sediments. Iron after entering into solution as carbonate is converted to iron carbonate, which then oxidizes as hematite (Wilson, 2004;Firth & Garden, 2008). This produces convolution of rocks and persists as insoluble deposits at a particular place for some period, developing some portion of regolith, that are eventually being transported by various agencies to the lake basin.…”

Influence of Basicity and Calcium-Containing Substances on the Consolidation Mechanism of Fluxed Iron Ore Pellets

“…The CaO produced by limestone decomposition in the low-basicity (0.4-1.0) green pellets could react with Fe 2 O 3 to form calcium ferrite and react with SiO 2 to form silicate during the preheating process [24]. With the increase in roasting temperature, calcium ferrite was preferentially melted.…”

Inhibition Mechanism of MgO Addition on High‐Temperature Oxidation of Magnetite: Density Functional Theory and Ab Initio Molecular Dynamics Methods Joint Research and Experimental Verification

“…No reaction of quartz grains occurs during the preoxidation process, and the bonding strength of quartzite grains with other minerals comes from the sintering of quartzite grains to the adjacent hematite and the glassy slag produced by acidic veinlets and bentonite. Andrew et al [6] DOI: 10.1002/srin.202200887…”