Effects of Mixing Variables and Mold Temperature on Prebaked Anode Quality

Abstract

Bench-scale work was carried out to determine effects of mixing time on quality of pressed and vibrated prebaked anodes. Effects of coke and pitch preheating and mix and mold temperatures were determined also. Green and baked apparent densities of pressed anodes increased by 0.02 Mg/m³ on increasing mixing time from 5 to 60 minutes. Most of the density increase occurred and baked anode electrical resistivity minimized after 30 minutes of mixing. Coke and pitch preheating had little effect on the bench-scale pressed anodes. A mold temperature 30°C over the pitch softening point (cube-in-air) improved pressed anode properties compared with a mold temperature 10ºC over the softening point. Vibrated anode properties were optimum with a 15-minute mixing time. With longer mixing times, properties were greatly degraded. A mix and mold temperature 40ºC over the pitch softening point was optimum for vibrated anodes.