The utilization of carbon dioxide (CO2) in chemical processes is one plausible solution for decreasing greenhouse gases in the atmosphere. Herein, a boric acid extraction process was developed utilizing CO2 as a leaching agent. Three-factor three-level Box-Behnken design model was employed to investigate and optimize process variables of temperature, pressure and reaction time for reactive extraction from ulexite mineral using carbon dioxide. A 91.8 % boric acid extraction yield was obtained at 70 degrees C and 9 MPa with a reaction time of 170 min. At the end of reaction, the heterogeneous mixture was separated by vacuum filtration. The presence of Na (8.72% wt.) in EDX analysis confirmed the crystallized powder has sodium borate. The filter cake was determined as calcium carbonate from the XRD and FTIR analyses. Utilizing supercritical CO2 as a leaching agent is a viable solution to sequester CO2 collected as calcium carbonate while also producing commercially relevant boric acid. (C) 2020 Elsevier B.V. All rights reserved.