Abstract: The process for the manufacture of special aluminas from the powder produced in the calcination of alumina hydrate, as proposed by the invention, achieves the recovery of this by-product, treating it separatedly from the rest of the alumina, in order to convert it into special alumina of high calcination degree, or alpha alumina, being adequate for uses other than aluminum production. The process is carried out by submitting the by-product to a water-washing stage that reduces its sodium content, solid and liquid separation, filtering and drying. A drying operation is finally carried out with a calcination at a high temperature wherein the alumina of high calcination degree is transformed into alpha alumina.