Efficient carbon dioxide (CO₂) reduction into carbon monoxide (CO) is required to establish a smart iron-making process based on an active carbon recycling energy system (iACRES). A disk-type solid oxide electrolysis cell (SOEC) was prepared and examined experimentally for application to the CO₂ reduction process in iACRES. A SOEC with a cathode|electrolyte|anode structure of Ni-YSZ|YSZ|La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ was fabricated. The electrolysis of carbon dioxide was conducted at 800–900°C. A current density of 107.1 mA cm^–2 was measured between the cathode and anode at 900°C and at 2.52 V. The production rates of CO and O₂ were in agreement with the theoretical values determined using Faraday’s law. Evaluation of iACRES using the experimental results indicated that an estimated 0.73 high-temperature gas cooled reactor units as the primary energy source for CO₂ reduction and a SOEC surface area of 0.098 km² were required for the reduction of 30% CO₂ in blast furnace gas emitted from a conventional blast furnace.