where k is the flotation rate constant of the liberation class and R1 is the ultimate recovery of the liberation class. The values for the flotation rate constant as a function of mean sulphide liberation and SIBX dosage are shown in Fig. 3. As seen in Fig. 3, the flotation rate constant increases with the increase of mean sulphide liberation,demonstrating that the particles containing higher percentage of copper sulphide minerals were better recovered than the particles with lower percentage of copper sulphide minerals. Additionally,the highest flotation rate constant was obtained when flotation pulp was conditioned in the presence of 50 g/t of SIBX.