A metallurgical furnace of the convertible type to an electric arc furnace or to a converter for conducting production processes for the production of metals in the molten state, in particular steel or cast iron, characterized in that it comprises: - a vessel comprising: - a lower shell for containing the metal bath, said metal bath being composed of molten metal and an overlying layer of slag, wherein said lower shell is tiltingly supported and is provided with a deslagging opening for evacuating the slag overlying the molten metal and with a tapping opening for tapping the molten metal, - a upper shell removably positioned on said lower shell and provided with - a first inlet opening for feeding, through the same, charge material in the solid state and which can be associated with a first feeding group for the continuous feeding of said charge material in the solid state and/or - a second inlet opening for feeding, through the same, charge material in the molten state and which can be associated with a feeding group for the continuous feeding of said charge material in the molten state, - a closing roof for the upper closing of said vessel, wherein said closing roof is removably positioned above said upper shell and is provided with a passage opening for the passage, through the same, of at least one electrode, at least one charge opening for feeding, through the same, charge material in the solid state, and at least one evacuation opening for discharging the gas fumes generated inside said furnace during the production process, - wherein at least one of said first inlet opening, said second inlet opening, said passage opening, said charge opening and said evacuation opening is closed or can be associated with a closing element of the removable type, - wherein said lower shell has a diameter D and said vessel has an overall height H ranging from 0.70D to 1.25D, said furnace being equipped with a group of injectors for the injection of oxygen and other gaseous or powder raw materials into said furnace, wherein said injectors are inserted in said upper shell at the lateral wall thereof. - a vessel comprising: - a lower shell for containing the metal bath, said metal bath being composed of molten metal and an overlying layer of slag, wherein said lower shell is tiltingly supported and is provided with a deslagging opening for evacuating the slag overlying the molten metal and with a tapping opening for tapping the molten metal, - a upper shell removably positioned on said lower shell and provided with - a first inlet opening for feeding, through the same, charge material in the solid state and which can be associated with a first feeding group for the continuous feeding of said charge material in the solid state and/or - a second inlet opening for feeding, through the same, charge material in the molten state and which can be associated with a feeding group for the continuous feeding of said charge material in the molten state, - a closing roof for the upper closing of said vessel, wherein said closing roof is removably positioned above said upper shell and is provided with a passage opening for the passage, through the same, of at least one electrode, at least one charge opening for feeding, through the same, charge material in the solid state, and at least one evacuation opening for discharging the gas fumes generated inside said furnace during the production process, - wherein at least one of said first inlet opening, said second inlet opening, said passage opening, said charge opening and said evacuation opening is closed or can be associated with a closing element of the removable type, - wherein said lower shell has a diameter D and said vessel has an overall height H ranging from 0.70D to 1.25D, said furnace being equipped with a group of injectors for the injection of oxygen and other gaseous or powder raw materials into said furnace, wherein said injectors are inserted in said upper shell at the lateral wall thereof. - a lower shell for containing the metal bath, said metal bath being composed of molten metal and an overlying layer of slag, wherein said lower shell is tiltingly supported and is provided with a deslagging opening for evacuating the slag overlying the molten metal and with a tapping opening for tapping the molten metal, - a upper shell removably positioned on said lower shell and provided with - a first inlet opening for feeding, through the same, charge material in the solid state and which can be associated with a first feeding group for the continuous feeding of said charge material in the solid state and/or - a second inlet opening for feeding, through the same, charge material in the molten state and which can be associated with a feeding group for the continuous feeding of said charge material in the molten state, - a closing roof for the upper closing of said vessel, wherein said closing roof is removably positioned above said upper shell and is provided with a passage opening for the passage, through the same, of at least one electrode, at least one charge opening for feeding, through the same, charge material in the solid state, and at least one evacuation opening for discharging the gas fumes generated inside said furnace during the production process, - wherein at least one of said first inlet opening, said second inlet opening, said passage opening, said charge opening and said evacuation opening is closed or can be associated with a closing element of the removable type, - wherein said lower shell has a diameter D and said vessel has an overall height H ranging from 0.70D to 1.25D,