Effect of supergravity field on the behavior of suspended dross in hot dip Al-Zn and purification

Abstract

Suspended dross is becoming the main factor affecting the surface quality of hot-dip coated steel. Hence, this paper developed a new method for its removal from industrial hot-dip Al–Zn (AZ) baths by using a supergravity field, whose effect on it was analyzed. The supergravity field forced the suspended dross to the top layer, and stratification occurred. As the gravitational constant (G) increased, the pure alloy ratio in the hot-dip AZ matrix increased and the suspended dross became more intensively confined in the top layer; at G = 1000, the pure alloy ratio reached 87.3%, with almost no suspended dross. A new shape factor for the suspended dross was proposed to determine via kinetic calculations its movement behavior under the supergravity field. The calculation results were consistent with the experimental data, laying the foundation for the separation and removal of suspended dross in hot-dip AZ baths by the supergravity field.