REAL (RECYCLING ALUMINIUM): SUSTAINABLE RECYCLING TECHNOLOGY FOR MULTILAYER PACKAGING

One of the primary applications of aluminium is in the production of aseptic carton and other multilayer packages. These materials play an essential role in terms of food safety and waste reduction, both of which are pressing global issues highly debated by society. The aluminium foil within these packages provides the most effective barrier against the ingress of oxygen and light, ensuring an extended shelf life for the stored products. However, these packages face a significant challenge when it comes to recycling, with aluminium being the most challenging component.
In Brazil, for example, only 30% of post-consumption aseptic carton packages are collected. This material is sent to paper mills where cellulose fibers are separated and recycled. Only a portion of the remaining material obtained after this process, known as Polymer-Aluminium (PolyAlu), is reused in the production of roofing tiles and panels, primarily. The unused material is sent to landfills.
Companhia Brasileira de Alumínio (CBA) has developed a patented technology called ReAL (Recycling Aluminium), which utilizes Bayer spent liquor from its refinery as the primary reagent. In this technology, firstly, the PolyAlu undergoes a process for removing residual fibers and contaminants. The cleaned PolyAlu is then subjected to a chemical step in which it reacts with Bayer spent liquor, dissolving the aluminium and transforming it into sodium aluminate. This sodium aluminate is sent back to the Alumina refinery's test tanks and follows the regular Bayer process stages. Hydrogen is also generated in this reaction, and it can be used as fuel in the calcination step, replacing up to 15% of natural gas. The polymer remains inert throughout the entire process. This polymer can then be recycled through mechanical processes, exhibiting excellent properties, and finding applications in products such as films and injection-moulded items, among others.
From an ESG perspective, this project increases the aluminium recycling rate, enhancing the circular economy and improving the income of individuals engaged in sorting and collection. Furthermore, it reduces CO2 emissions due to hydrogen usage in the calciners, lowers the overall energy consumption of the refinery, decreases the use of natural resources, and minimizes residue generation.