A hearth for a metallurgical furnace, in particular for a blast furnace, the hearth including a wall lining and a bottom lining of refractory material for containing a molten metal bath, the bottom lining including a lower region and an upper region that is arranged to cover the top of the lower region and that is built of ceramic elements, the ceramic elements of the upper region being made of microporous ceramic material including a granular phase made of a silico-aluminous high alumina content granular material and a binding phase for binding grains of said granular material, said microporous ceramic material having thus an maintaining permanently a thermal conductivity lower than 7 W/m.° K.