Water Model Experiment on Coagulation, Entrapment by Liquid/Liquid Interface and Bubble Flotation of Inclusions in Molten Copper

Abstract

It is well known that inclusions deteriorate the quality of copper products. To improve the quality, it is necessary to make clear the kinetic behavior of inclusions in molten copper and optimize operation conditions and processes. However, a model that can predict the number concentration and distribution of inclusions in molten metal has not been developed enough. Therefore, the kinetic behavior on coagulation of inclusions, entrapment of inclusions at liquid/liquid interface, such as between molten copper and flux, and removal by bubble flotation was investigated. In present study, a change in particle number density with time was measured by a water model experiment using a gas stirred vessel. And a predictive model of particle number density by coagulation, entrapment at liquid/liquid interface and bubble flotation was constructed and verified comparing with the experimental values. As a result, the calculated values agreed with experimental values approximately and the present model was appropriate. In the analysis using the model, it was found that the effect of entrapment on change in particle number density was dominated at the low particle number density and the effect of coagulation was dominated at the high particle number density. From the viewpoint of inclusion removal, it was considered that the entrapment was main mechanism in the present experimental condition and the effect of bubble flotation on inclusion removal became relatively large in the case that gas flow rate was increased.