Detailed particle‐fluid simulations of moving bed reactors such as blast furnaces (BFs) are computationally very expensive. The wide range of temporal scales from short‐lived micromechanics to slow, macroscopic transport makes it almost impossible to study e.g., heat transfer over process‐relevant time scales. However, a recently introduced approach that uses high‐fidelity data obtained with the discrete element method (DEM) enables extremely fast data‐assisted simulations. Using this methodology, calculations are conducted, which are efficient enough to study granular motion through a BF slot model subject to heat transfer between the hot blast and the solid phase over many hours. These long durations make it possible to determine the thermal steady state including shape and location of the cohesive zone (CZ). While other approaches either have to predefine its properties or are bound to very small domain sizes, this novel strategy is applied to a large‐scale BF slot model with about 28 m height and 15 m width with hardly any prior knowledge. It constitutes an important step toward virtual experiments on BFs under realistic conditions and will allow researchers to gain new insights, perform variations of operating parameters, and ultimately build an online monitoring system.