Abstract: The thermodynamics of solvent extraction of Tc with 2-butanone was investigated in the NaOH system using cyclohexane as the diluent. The results show that the ratio of organic and aqueous phase and the concentration of NaOH have obvious effect on the ratio of extraction, leading to the ratio of extraction increases with the phase ratio and the concentration of NaOH. The extraction equilibrium is achieved within about 8 min and the process is exothermic. Additionally, the apparent equilibrium constants and thermodynamic functions for the extraction process at different temperature were calculated.