ELECTRIC ARC FURNACE

A direct current plasma arc furnace (1) for melting and/or treating a material by production of electric arcs and providing a molten product, the furnace (1) comprising; a tank (10) comprising: a crucible (12) delimiting a chamber (11) configured to receive material to be melted and/or treated; a plurality of refractory walls surrounding the outer surface of the crucible (12); and a metallic frame (15) covering the refractory walls; and a heating system configured for heating the received material, the heating system comprising a first electrode acting as cathode (13) and a second electrode (120) acting as anode, wherein the first electrode acting as cathode (13) is a movable electrode configured to project vertically into the chamber (11) delimited by the crucible (12). The crucible (12) is made of a material comprising at least 98% of synthetic graphite, the crucible (12) being part of an anode system also comprising said second electrode (120) and at least one part (12', 12") connecting the crucible (12) and the second electrode (120), said crucible (12) having a double function: receiving and holding material to be melted and/or treated and providing electric conduction for the flow of current to heat said material, in such a way that, in use of the furnace (1), the voltage potential difference between the cathode (13) and any point of the surface of the crucible (12) defined to be in contact with the material to be melted and/or treated is the same.