leached with h 2 so 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 application_number US 94456707 A description further features and advantages of the invention will become more readily apparent from the following description of various embodiments as illustrated by way of examples only in the appended drawings wherein as it can be seen from fig1 such a process is relatively simple and it can be carried out easily without requiring tedious tasks the aluminium dross residues are first treated with hcl so as to obtain a mixture comprising a solid and a liquid then for example upon filtration the two phases liquid and solid can be separated from one another the liquid is then hydrochlorinated for example by using gaseous hcl thereby forming aluminium chloride the aluminium chloride so obtained can eventually be converted into alumina via a pyrolisis alternatively aluminium chloride can be converted into alumina by means of a pyrohydrolysis according to the following reaction as shown in fig2 the aluminium dross residues are treated with hcl and a mixture comprising a solid and a liquid is obtained the mixture is treated for example by filtration so as to separate the liquid from the solid the solid is then submitted to a leaching treatment with h 2 so 4 and a solid containing various minerals and metals such as sulphates is thus obtained this solid is then treated with an aqueous solution so as to solubilize the minerals and metals contained therein thereby providing a leachate which can comprise sulphates then the liquid and the leachate are combined together and they are hydrochlorinated for.