The objective of this paper is to study the utilization of a mixture of marble waste and kaolin in the hot metal desulphurisation. In this work, marble waste, kaolin, fluorite and pig iron were used. First it was done marble waste and kaolin characterization through their chemical analysis and particle size. Then it was elaborated four different mixtures which were added in a bath of pig iron at 1,450oC with known composition, besides the utilization of pure lime in an experiment and pure calcium carbonate in other one. Samples were collected by vacuum sampling and analysis to check the variation of sulfur in the bath was made. By analyzing the results of the additions, it can be seen that the best result was obtained when using the marble waste mixed with fluorite, surpassing the materials commonly used in steel