There is provided a process for preparing aluminium chloride comprising: leaching aluminium dross residues with HCl so as to obtain a mixture comprising a solid and a liquid; and hydrochlorinating the liquid obtained from the mixture, so as to form a precipitate comprising aluminium chloride. Such a sequence can also be used for preparing alumina. In such a case, the process can further comprise the step of converting the so-obtained aluminium chloride into alumina. In the processes previously defined, the solid so-obtained can also be leached with H.sub.2SO.sub.4, thereby generating a leachate. The leachate can also eventually be hydrochlorinated so as to increase the yield of the desired product obtained i.e. alumina or aluminium chloride.