A melting furnace for metallurgical plant comprising a vessel provided with a bottom; a tapping duct passing through the bottom; rotation means to rotate the vessel so that the tapping duct passes from a first reference position to a second position inclined with respect to said first reference position, and vice versa; wherein said tapping duct has a first stretch arranged in the thickness of the bottom and completely passing through the bottom, and a second stretch, adjacent to the first stretch, protruding inside the vessel; wherein there is provided a cover of the second stretch shaped as a tube closed at an upper end thereof and open at a lower end thereof; said tube being coaxial and spaced from said second stretch, and being spaced from a zone of the bottom which includes the first stretch of the tapping duct, whereby the cover, in cooperation with the second stretch of the tapping duct, acts as a tapping hood.