Design of a cement kiln dust recovery process for CO2, SOx, and NOx capture and utilization using a microbubble scrubber

Abstract

Cement kiln dust (CKD) is generated as waste during cement production, and a substantial amount of CKD is landfilled, thereby increasing its negative impact on the environment. However, the industrial application of CKD aimed at reducing its environmental impact is a challenging task. This study proposes a novel CKD recovery process for CO2, SOx, and NOx capture using a microbubble scrubber (MBS). The process involves two main steps: first, metal-ion separation from CKD to produce Mg(OH)2, Ca(OH)2, and KOH; second, the use of a Microbubble Scrubber (MBS) system. The MBS system utilizes these hydroxides to simultaneously capture SOX, NOX, and CO2 by enhancing surface area with microbubbles, thereby reducing emissions and potentially enabling the reuse of captured pollutants. Finally, sulfurization and carbonation are performed by generating additional products, such as metal carbonates, sulfates, and nitrates. The designed process exhibits the maximum capture efficiencies of CO2 (92 %), SOX (99 %) and NOX (38 %) payback period of 0.45 years, which confirms its economic feasibility."