Gravity dust-catchers are widely utilized in steelmaking plants to separate particles from the gas flow produced by the blast furnace (BF). The BF recycle system often experiences high total suspended solid (TSS) levels with a significant increase in sludge generation. This increased sludge generation results in higher costs in operation, chemical treatment and sludge removal. Due to the environmental limitations inside an operating dust-catcher, direct measurement of operating conditions can be extremely difficult. Computational fluid dynamics (CFD) models provide a method of gaining an understanding of the operating conditions and phenomena that occur inside a blast furnace dust-catcher on both full process and detailed levels. In this paper, a numerical geometry of the dust-catcher is designed and simulated under typical operating conditions. The Discrete Phase Model (DPM) is employed to track the flow patterns and paths of dust particles. The collection efficiency performance is evaluated at different conditions (quarter full, half full, and three quarter full). From these results, an alternative design to enhance process efficiency is proposed and investigated.