Optimization of boric acid extraction from ulexite mineral by using supercritical carbon dioxide

İpeksever S., GÖNEN M.

Journal of Supercritical Fluids, vol.166, 2020 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 166
  • Publication Date: 2020
  • Doi Number: 10.1016/j.supflu.2020.104998
  • Journal Name: Journal of Supercritical Fluids
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Food Science & Technology Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: Boric acid, Reactive extraction, Supercritical CO2, Sequestration, Box-Behnken design, DISSOLUTION KINETICS, LEACHING KINETICS, CO2 SEQUESTRATION, COLEMANITE, ORE


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.