This paper presents a novel and effective way for copper smelting with lower carbon emissions, where biodiesel is used as the fuel Instead of diesel. In this study, we developed a two-phase numerical model to simulate the top blown injection copper smelting process and we examined the dispersion characteristics of biodiesel spray droplets ejected from the lance nozzle tip immersed in water. The dispersion characteristics of the biodiesel spray droplets were examined at various air-fuel ratios and calculation model was verified by test. The results show that spray tip penetration distance of the biodiesel spray droplets increases while the mean diameter decreases with an increase in the atomized air velocity. The axial velocity of the atomized air is significantly reduced within the bubble generated at the nozzle tip and the axial velocity is 0 m/s when the distance between the nozzle tip and bottom of the bubble is 10-12 mm. The axial velocity of the biodiesel spray droplets slightly increases and then significantly decreases within the bubble generated at the nozzle tip. The axial velocity of the biodiesel spray droplets tends to stabilize when the spray droplets enter the water region of the two-phase model.