The cement industry accounts for a significant share of global greenhouse gas (GHG) emissions due to the calcination of limestone and fossil fuel combustion during clinker production. To mitigate these emissions, carbon mineralization using Cement Kiln Bypass Dust (CBPD) offers a promising solution, as capturing CO₂ while enabling potassium chloride (KCl) recovery. This study aims to assess the environmental and economic feasibility of a CBPD-based carbon mineralization and KCl recovery process as an alternative to landfilling. A Life Cycle Assessment (LCA) following the IPCC (2021) GWP 100 method was conducted to estimate CO₂ reduction, and a Benefit–Cost (B/C) analysis was performed using process data derived from pilot-scale operation and mass balance modeling. The results indicate that the developed process achieves a net GHG reduction of –0.156 kg CO₂-eq per kg of CBPD, confirming its carbon-negative performance. In addition, the process was found to be economically viable, yielding a net profit of 315,041 KRW per ton of CBPD and a B/C ratio exceeding 3.0, primarily due to revenue from CaCO₃ and KCl recovery and carbon credit trading. Overall, the proposed technology demonstrates strong potential for industrial-scale decarbonization in the cement sector by transforming a landfill-bound by-product into valuable mineral and chemical resources. Future research should focus on scaling up, LCA–TEA integration, and policy linkage to promote commercialization and inclusion within circular economy and carbon neutrality frameworks.