A hydrometallurgical perspective of aluminium dross recycling

Abstract

To meet the objective of recovering aluminium from aluminium dross, it is essential to recycle it and save natural resources for posterity. Aluminium dross, a waste generated in an enormous quantity, is formed over the top surface of the molten bath when the surrounding oxygen comes into contact and forms a thick semi-solid layer of oxide. Pure metallic aluminium, which is entrapped within the oxides, is extracted using three different routes i.e., Pyrometallurgy, hydrometallurgy and hydrothermal. Metallic aluminium is recovered using the pyrometallurgical route by melting dross in a rotating furnace. In hydrometallurgy, chemical treatments of dross ensures the synthesis of a wide range of products. Newly developed technique like hydrothermal is used to produce zeolites, molecular sieves, and many other useful products. Apart from the solid products, gases like H2, NH3 and CH4 are produced by recycling dross when the Al-water reaction takes place in the presence of acids or alkalis. The present study comprises major aspects of dross recycling via the hydrometallurgical route.