Red mud filtration test results using afp iv™ automatic filter press

Abstract

The results of pressure filtration testing demonstrates that a standard design FLSmidth AFP IV™ filter press can dewater red mud from initial feed concentrations of between 30-44 wt% and produce final cakes containing 67 - 70 wt% solids. This paper outlines various factors affecting the filtration rate and final cake solids concentration such as feed solids concentration, slurry temperature and feed pump delivery rate/pressure relationship as well as the configuration of the filter plates. The results are presented for different bauxite grades. Additional testing was performed to obtain filter cakes containing 75 wt% cake solids by evaluating high-pressure filtration at 30 - 60 bar using both recessed plate and membrane plate configurations. The tests demonstrate that high-pressure filtration above 30 bar can produce 75 wt% solids.