A review on direct hot extrusion technique in recycling of aluminium chips

Recycling of industrial waste is a subject of great importance today in any sector and more so in the aluminium industry. Aluminium recycling could sustain material resources, reduce the usage of energy, ease greenhouse gas emission and save the environment. This study examines the usage of direct hot extrusion of aluminium chip in the recycling of aluminium, focusing on the end product, properties and processing route. The process directly converts the new scrap of aluminium chips generated from industries to aluminium-based composite or aluminium alloys. The properties of the extrudates depend on the process parameters and the alloying elements added to the aluminium chips. High shear strain is required to disperse the oxide layer on the surfaces of the chip, thus permitting a contact between the newly exposed aluminium chips, and is consolidated to form a solid semi-finished product. The technique can be done through various process combinations and routes. The selection of process combination and routes depends on the product type and properties, degree of contamination of chip and size. The technique is proven as a viable method for aluminium recycling.