CONVERSION TO FILTERED TAILINGS: COMMISSIONNING AND RAMP-UP OF RIO TINTO’S BAUXITE RESIDUE FILTRATION PLANT

In November 2019, Vaudreuil’s team commissioned its Bauxite Residue Filtration Plant (BRFP) comprising four (4) filter presses, each one having 750 m2 of filtration surface to treat an average of 4300 m3 of thickened bauxite residue per day. This was the first significant change in residue treatment since the implementation of deep thickeners in the late 80s and mud farming in the early 2000. With the Bauxite Residue Disposal Area (BRDA) reaching its physical limit, the previous thickened tailings disposal combined with summer mud farming was no longer an option to ensure sustainability of Vaudreuil’s alumina refinery. This article provides an overview of the filtration technology chosen by RTA-Vaudreuil and outline the team's approach in achieving the designed filtration rate and ensuring equipment availability in the plant. The focus will also be on modification of upstream processes to achieve residue with desirable filterability. It will present a comprehensive review of operating strategies and maintenance tactics employed, ranging from bauxite mills down to mud washers. New key performance indicators and new operating limits were defined to ensure compliance with production and disposal criteria. The work also covers the changes in material management that were implemented at the BRDA over the years, and more recently with filtered tailing, to bring Vaudreuil beyond 2022 and covers the next improvements that will be considered to improve BRFP reliability.