Simultaneous reduction of Si and Ca occurs in silicocalcium production. The concentration dependence of interaction rate of CaO-SiO2 melts with graphite at 1873 and 1823 K is investigated over the concentration range of 45-65 wt.% SiO2. Statistical processing the experimental data obtained by gravimetric method, shows that the error in the determination of rates is not more than 10%. It is inferred that the process proceeds in kinetic regime by electrochemical mechanism.