Fremgangsmåde til fremstilling af lerjordshydrater ved fældning af aluminiumsalte i nærværelse af tinkrystaller

In the production of hydrated alumina (I) by precipitation from basic and/or acid aluminum (Al) salts, precipitation is carried out from an aqueous medium containing crystallization seeds, which have an average diameter of 12-250 nm in the medium. In the production of hydrated alumina (I) by precipitation from basic and/or acid aluminum (Al) salts, precipitation is carried out from an aqueous medium containing crystallization seeds, which have an average diameter of 12-250 nm in the medium and comprise (a) (I) and/or alumina seeds and/or (b) organic polymer/oligomer forming a lattice in the medium, in an amount of 0.1-5 wt.% with respect to (I), calculated as oxide (Al2O3). An Independent claim is also included for boehmitic and/or pseudoboehmitic alumina with a pore volume of 1.0-1.6 ml/g and an average pore radius of 6-12 nm at a crystallite size of 3-5 nm, determined at 120 reflection, produced by this process.