Due to economic reasons, great efforts have been made to increase the scrap usage in basic oxygen furnaces (BOF) and in secondary refining ladles. The mechanism of melting of scrap in above mentioned reactors is not clear. Water models can be used to simulate the motion and melting process of scraps. In this study, the ice sphere and ice sphere made by saturated KCl solution, which can simulate the light and heavy scraps, are used in water mode experiment to study the motion process and melting mechanism in BOF-like vessels and ladles. The results show that the melting time of ice samples are not affected by freezing time when the freezing time is longer than 18 hours. The shape of ice sphere and ice sphere made by saturated KCl solution during melting is spherical or ellipsoidal. The diameter of both sphere decreases linearly with time. With the increase of bath temperature, the melting of both ice samples accelerates. Furthermore, the mechanism of motion of ice sphere and ice sphere made by saturated KCl solution is significantly different due to the flow field difference with respect to the variance of liquid level and gas flowrate. Specifically, the melting time of ice sphere decreases with the increase of liquid level, while the melting time of ice sphere made by saturated KCl solution decreases dramatically first and then increases slightly. The melting time of the ice sphere made by saturated KCl solution is the lowest at the position where the ratio of liquid level to the diameter of the reactor is 0.94. In addition, adding ice sphere made by saturated KCl solution above the gas plume will significantly reduce the melting time when the liquid level is low (the ratio of liquid level to the diameter is 0.42~0.73). However, the addition position will not change the melting time when the liquid level is high (the ratio of liquid level to the diameter is 0.83~1.04).