Advancing Sustainably: Construction progressing on Residue Filtration facility in Brazil

Defining what it means to be a sustainable aluminum company requires a deep commitment to continuous improvement and a relentless pursuit of innovation. That’s certainly true in our global refining system, where new technology is working to save water and reduce land use.

Two of our refineries in Australia were the first in the industry to adapt press filtration to manage bauxite residue, a by-product that consists primarily of red mud and coarse sand. Now, the technological learnings are being transferred to Brazil, where a new press filtration facility is under construction at our Poços de Caldas refinery.

“We are very proud to be the first Alcoa plant in Brazil to implement the press filtration project, which is fundamental for the continuity of our operations in Poços de Caldas,” explained Fabio Martins, Poços de Caldas General Plant Manager. “This project has a strong sustainability appeal, in addition to increasing the safety of our operations.”

The construction work began in August 2021 and is expected to be complete in the second quarter of 2022, with commissioning by the end of the year. The construction involves 15 companies and approximately 360 people. When finished, it will help transform the way bauxite residue is processed at the Poços de Caldas location.

“We have completed the entire foundation and walls supporting the filters and the assembly of the metal structures, tanks, pipes and floors is in progress,” said Rodrigo Giannotti, Refinery Manager and project leader in Poços de Caldas. “The first filter will be commissioned at the end of May, starting the change in technology to the dry storage method.”

Alcoa first adapted the press filtration technology at the Pinjarra and Kwinana refineries in Western Australia. Those two refineries now have the capability to reduce freshwater use by a collective 2.2 gigaliters (581 million gallons) through the process. This is equivalent to the amount of water needed to fill 880 Olympic-sized swimming pools.

Brad Klopper, Alcoa’s Global Residue Filtration Technology Manger, explained: “This innovative technology allows us to improve our business in a number of different aspects. The geotechnical stability of our reside areas is improved. We reduce our land use, and we significantly reduce our freshwater usage.”

Traditionally, bauxite residue is sent to drying areas as a slurry and then dries in the sun. “Now, with filtration,” Klopper said, “we remove the moisture from the cake and significantly reduce our freshwater usage. In the drying climate of Western Australia, that is a major, positive operational impact.”

Alcoa has a global goal to reduce global bauxite residue land requirements per metric ton of alumina produced by 15% by 2030, from a 2015 baseline. Alcoa continues to build partnerships focused on developing innovative pathways for bauxite residue re-use, turning the waste product into a resource. Other examples include using the residue as a material for low-carbon cement as well as transforming it into a soil-like substance.

The reduction of bauxite residue is also one of several process improvements Alcoa is developing for its Refinery of the Future project, which intends to unlock decarbonization at scale and deliver a cost-competitive refinery that can eliminate fossil fuels from the refining process and bring other operational improvements.