Structure Formation Mechanisms in Wet and Dry Pellets of the “Clay Mineral–Iron Ore Concentrate” Composite System

This article examines the interaction of clay minerals with iron ore concentrate in the context of the efficient use of composite mineral resources. The role of the adsorption properties of mineral additives in the formation of interparticle bonds in green pellets is analyzed. Using X-ray diffraction (XRD) and infrared spectroscopy, the dehydration processes of Na- and Ca-montmorillonite were investigated, and the influence of the cation type on the minerals’ ability to retain water was established. The high thermal stability of the structural OH groups of montmorillonite from the IV-layer clay of the Cherkasy deposit was confirmed, which is an important factor during high-temperature processing of mineral raw materials. Electron microscopy results showed that the fourth-layer clay forms an optimal porous composite microstructure, which contributes to increased water-holding capacity and gas permeability of the pellets. A direct correlation between the adsorption capacity of mineral additives and the strength of raw and dried pellets was experimentally confirmed. Montmorillonite with palygorskite from Layer IV, characterized by high adsorption capacity and prolonged dehydration processes, was identified as the most effective composite binding additive. The results obtained deepen scientific understanding of the mechanisms underlying pellet strength formation and have practical significance for the rational and resource-efficient use of mineral resources in the production of iron ore pellets. The results also demonstrate the potential for improving resource efficiency in pellet production through reduced consumption of traditional binder materials.