Modified cathode with protrusions in aluminum reduction cell

School of Metallurgy, Northeastern University, Shenyang 110819, P.R. China
e-mail: pengjp@smm.neu.edu.cn

Received: 8 September 2015
Accepted: 8 February 2016

Abstract

A three-dimensional (3-D) finite element model of the aluminum electrolysis cell was established to determine the consequence of modified cathode with protrusions which were designed to increase the flow resistance. Electromagnetic field and velocity were calculated in ANSYS and CFX respectively at a constant aluminum level. The protrusions occupy some space in the metal, making metal height smaller and higher horizontal current. Results show that due to the protrusions, peak value of horizontal current density component J_x was increased from 6075 A/m² to 8475 A/m². Maximum J_y was increased from 253 to 3129 A/m². The maximum metal velocity in the cells with traditional cathodes and modified cathodes was 14.5 cm/s and 13.8 cm/s respectively. The protrusions-restrained impact in the metal was found more effective than the negative impact that higher horizontal current density brought. The wave crests calculated due to previous cathodes were found to be 2.3 cm and 2.0 cm, respectively. The protrusions block the metal flow, creating less intensive metal motion and eddies between protrusions, which can promote the dissolution of alumina.