Critical solution surface tension for liquid–liquid extraction

This paper introduces a strong correlation between the solution surface tension and the liquid–liquid extraction process of minerals. It was found that the liquid–liquid extraction recoveries of celestite, magnesite and dolomite minerals decreased with decreasing solution surface tension, and eventually the liquid–liquid extraction of these minerals did not take place below a particular value of the solution surface tension. The solution surface tension value at which liquid–liquid extraction does not occur was defined as ‘the critical solution surface tension for liquid–liquid extraction, γc-e’. Consequently, the solution surface tension value for a successful liquid–liquid extraction of a mineral must be higher than the critical solution surface tension of liquid–liquid extraction (γc-e) value. In addition, the experimental results have demonstrated that the γc-e values obtained from liquid–liquid extraction tests of these minerals were slightly higher than their critical surface tension of wetting (γc) values based on the contact angle measurement technique. These differences between the γc-e and the γc values indicate that the liquid–liquid extraction process of the minerals took place after reaching a sufficiently low wettability.

Graphical abstractThere is a critical value of solution surface tension for achieving the liquid-liquid extraction process of minerals. This critical value of the solution surface tension can be defined as ‘critical solution surface tension for liquid-liquid extraction, γc-e’.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ This study indicates a strong correlation between surface tension and liquid–liquid extraction. ▶ The surface tension at which liquid–liquid extraction does not occur has been defined as ‘γc-e’. ▶ The γc-e values are slightly higher than the critical surface tension of wetting (γc) values.