A system and method for continuous casting. The system includes a melt chamber, a withdrawal chamber, and a secondary chamber therebetween. The melt chamber can maintain a melting pressure and the withdrawal chamber can attain atmospheric pressure. The secondary chamber can include regions that can be adjusted to different pressures. During continuous casting operations, the first region adjacent to the melt chamber can be adjusted to a pressure that is at least slightly greater than the melting pressure; the pressure in subsequent regions can be sequentially decreased and then sequentially increased. The pressure in the final region can be at least slightly greater than atmospheric pressure. The differential pressures can form a dynamic airlock between the melt chamber and the withdrawal chamber, which can prevent infiltration of the melt chamber by non-inert gas in the atmosphere, and thus can prevent contamination of reactive materials in the melt chamber.