Dissolution Rate of Stationary Solid Copper Cylinder into Molten Al-Cu and Mg-Cu Alloys

Abstract

In order to provide the fundamental data for the removal of copper from ferrous scrap by metallic bath immersion process, the dissolution rates of stationary copper cylinder into molten Al-Cu and Mg-Cu baths were measured as a function of temperature and the composition of molten bath. Furthermore, kinetic analysis was conducted with respect to mass transfer and diffusion coefficients. It was confirmed that both the molten baths of Al and Mg systems can dissolve solid copper very rapidly and have much greater mass transfer coefficient than the other metals such as Pb and Bi do so. The dissolution rate and mass transfer coefficient are substantially the same for the both baths and decrease with the increase of Cu concentration of molten baths. Apparent activation energy of mass transfer are in the range of 32 to 40 kJ/mol for Mg-Cu system and about 30 kJ/mol for Al-Cu system. In the case of Al-Cu system, diffusion coefficient is almost unchanged by varying Cu concentration of molten bath. In Mg-Cu system, however, it markedly decreases with increasing Cu concentration, particularly in the concentration range more than about 30mass% Cu and underlies that for Al-Cu system. © 1994, The Iron and Steel Institute of Japan. All rights reserved.