A unique in blow sampling system has been applied to a blowing converter to retrieve simultaneously representative bulk metal bath and slag/metal emulsion samples from seven specified positions and every 2 min from start of blow. Full sample datasets from 20 heats have been grouped according to differences in the bulk bath phosphorus removal profiles and analysed with respect to relative refining ability of the slag/metal emulsion and the bulk metal bath. The complexity of the thermokinetic relationships behind the removal of carbon and the transfer of silicon, phosphorus, manganese and sulphur between the metal and slag is highlighted and the metal circulation rate in the emulsion is derived. © 2011 Institute of Materials, Minerals and Mining.