Abstract: The open turbine rotating disc contactor (OTRDC) is a novel rotary agitated extractor based on the rotating disc contactor (RDC) in order to handle systems with high solid particle content. Its structure is similar to the RDC except three narrow strips added on the lower surface of each rotating disc. A number of experiments on hydrodynamics and mass transfer for a water-kerosene-quartz particles system were carried out in a 52 mm diameter contactor with butyric acid as solute. The experimental results showed that the direction of mass transfer has some effect on the liquid dispersed phase holdup, solid phase holdup and overall volumetric mass transfer coefficient. The correlation of characteristic velocity must be corrected under solute transfer conditions. The presence of solid particles will result in a smaller height of dispersion transfer units, but it may be unfavourable to the mass transfer in some cases.