Boron extraction from original alkaline brine using synergistic extraction system

This paper presents a novel system and method for the extraction and separation of boron from alkaline solutions. The extraction system consists of a 1:1 molar ratio of 2-octanol and salicylate ester, which effectively extracts boron from the solution. The extraction efficiency of boron increases with the pH of the solution, reaching up to 75% in a single extraction stage when pH > 9. The study also investigates the effects of extraction ratio, extraction time, and extraction temperature on the extraction performance. Under optimized conditions, using natural salt lake brine from Tibet as the raw material, a three-stage countercurrent extraction process can achieve a boron extraction rate of 95%. After subsequent stripping and concentration, boric acid can be directly produced with a purity exceeding 99%. Moreover, the extraction system demonstrates good stability during the extraction-stripping cycle. FT-IR and Raman spectrum were employed to investigate the main functional group of the extraction process, and DFT was used to study the coordination mechanism. This work provides an effective pathway for the comprehensive utilization of boron in alkaline solutions.