IMPACT OF PARAMETER CHANGES ON THE ALUMINUM RECOVERY IN A ROTARY KILN

摘要

The remelting process of a coarse metal fraction in a rotary kiln was investigated to research the effects of salt flux quantity, fluoride addition, aluminum oxide content, temperature and rotation speed of kiln on metal yield, salt slag properties and its constitution. The metal recovery of the aluminum scrap remelting in a short rotary kiln is stromg influenced by metal losses in salt slags due to the lack of coalescence of dispersed droplets. The effects of fluoride type and concentration, kind of aluminum alloy and temperature on the coalescence of aluminum droplets in salt flux was investigated. In order to explain the observed behaviour of CaF_2, the polythermic section of the ternary system NaCl-KCl-CaF_2 related to salt fluxes was studied. Flour ion is discussed as an active constituent of salt melts promoting the coalescence and also affecting the interfacial tension between aluminum and flux.