In a solvent extraction settler arrangement the outlet box comprises an inner tube arranged vertically inside a shaft, the inner tube being spaced from the side wall of the shaft to define an intermediate space between the inner tube and the shaft. The inner tube has an inner space and an opening at the lower part of the inner tube adjacent the bottom to form a flow path for the heavy solution phase to flow to the inner space. The shaft comprises a second outlet which is separate in relation to the discharge outlet and above the level of the discharge outlet. The second outlet opens through the side wall to the intermediate space at a location adjacent to the upper end of the shaft and at the level of said layer of entrained light solution phase for discharging said layer of entrained light solution phase from the intermediate space.