The Client is a big Group having one of the most important Alumina Refineries in North America using the Bayer Process by leaching the bauxite ore with caustic soda. The generated waste is a slurry called “Red Mud”. The Red Mud, containing caustic soda, was pumped to big tailings ponds where it was stored for years in a semi-liquid phase. The capacity of the ponds was going to be saturated in about few years and this was a potential threat for the future operation of the refinery. It was necessary to adopt an alternative method for the red mud management considering the limited availability of space for the disposal of the material. The dewatering with filterpress was the preferred one mainly for the following reasons:

• Highest dewatering level (cake dryness >73%).
• Lower risks for the environment and the surrounding community.
• Reduced footprint of the disposal area.
• Maximum recovery of caustic soda.

Diemme^® Filtration, who is World Leader with the treatment of red mud, has been involved from the beginning with the execution of a thorough pilot campaign at the site working hand in hand with the client in order to design the equipment to meet specifically the strict targets and site standards. It was also fundamental to meet the agreed deadlines in order to maintain the production of the plant. The installation of a system with 4 filterpresses mod. GHT2500F18 presented numerous challenges but eventually reached the targeted parameters (>4.600 tpd of solids with >73% of cake dryness). The close and open cooperation between the parties generated a trusted partnership which led to a successful project which is now state of the art in this Industry.