Hot pressing has been investigated for the production of transparent MgAl 2 O 4 aimed at the scaling up of the process. Other assessed techniques (hot isostatic pressing, spark plasma sintering) can hardly be used for the production of flat components with large dimensions and good planarity.Hot pressing of stoichiometric Al 2 O 3 –MgO powder mixtures has been preferred to the direct pressing of spinel powder for the readily availability of pure powders and to exploit the thermodynamic driving force of the spinel formation. LiF has been used as sintering additive.A thermodynamic investigation of the reactions involving LiF, MgO and Al 2 O 3 has helped in the comprehension of the densification mechanisms affecting the transparency of spinel. Transparencies up to 70% in the visible range (highest value 78% at 1100nm) have been obtained. Suitable soakings have been added for promoting the initial liquid phase sintering and the release of LiF through formation of vapour phases.