This paper proposes a novel direct casting method of alumina suspensions using alginic acid salt and the coagulation agent hydroxyaluminum diacetate (HADA). These two compounds allowed the consolidation of alumina suspensions through a simultaneous time-delayed physical and chemical gelation process. The physical gel was formed by the gradual release of aluminum and acetate ions from the HADA in water, while the chemical gel originated from the cross-linking of alginate molecules by the polyvalent aluminum ions. Wet alumina green bodies displayed enhanced mechanical properties with the addition of minimal contents of organic material (< 0.1 wt%).