4-Tert-butyl-2-(alpha-methylbenzyl) phenol (t-BAMBP) was used in cyclohexane in the extraction of rubidium from brine sources containing lithium. The effect of t-BAMBP concentration and aqueous phase pH on the rubidium and lithium extraction equilibrium was studied. t-BAMBP/cyclohexane was efficient and selective for rubidium extraction with optimal operating conditions being pH of 13.0 and initial t-BAMBP concentration of 1.0 mol.L- 1. The stoichiometry of the complex of t-BAMBP with rubidium is 4:1. The apparent extraction equilibrium constant of rubidium was calculated by fitting the experimental data. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.