This patent describes economical and environment-friendly processes for the synthesis of Al-containing non-Mg anionic clays. It involves hydrothermally reacting a slurry comprising a divalent metals source with an aluminum source to directly obtain Al-containing non-Mg anionic clay, the Al source being aluminum trihydrate or its thermally treated form. There is no necessity to wash or filter the product. It can be spray dried directly to form microspheres or can be extruded to form shaped bodies. The product can be combined with other ingredients in the manufacture of catalysts, absorbents, pharmaceuticals, cosmetics, detergents, and other commodity products that contain anionic clays.