Recycling and valorisation of carbon fibre reinforced aluminium

Abstract

Composite materials are nowadays widely used, and their demand is growing over the years thanks to their exceptional mechanical properties such as high fatigue strength, high stiffness, and low density. They are found in different sectors such as aeronautics, automotive, defence, wind power and others. The most used metal matrix in composite materials is aluminium due to its lightweight, high thermal conductivity, and wear resistance. However, when these composite materials reach the end of their useful life, they are mainly incinerated or forgotten in landfills. Today, there are no definitive methods for their recycling and recovery as these materials are very difficult to treat due to their high stability and strength. It is necessary to develop an efficient treatment methodology to transform this type of waste into resources in order to continue supplying the needs of industry within a circular economy model. The aim of this work focuses on the treatment of aluminium matrix composites reinforced with carbon fibres, giving them a new life cycle, and contributing to the circularity of this type of materials. Firstly, most of the aluminium is recovered through smelting processes, thus recovering a carbon fibre impregnated with aluminium. Afterwards, a complete removal of the aluminium from the carbon fibre is carried out by acid and base treatments. Finally, the aim is to extend this study to other metal matrix composite materials.