Danieli & C. Officine Meccaniche S.p.a.

Corrado De Cecco

Gianni Gensini

Giovanni Coassin

Matteo Vittorio Losciale

Sergio Gerussi

Melting method for an electric arc furnace with alternative sources of energy for the melting of iron-based alloys, the electric furnace (10) including tuyeres (13) positioned on the bottom to deliver oxygen, at least one tuyere (15) to deliver coal dust which works in the area of contact between the bath of molten metal (16) and the layer of slag (22), at least one supersonic lance (12) cooperating with a lance (29) to deliver coal dust, these lances (12, 29) having a working position (12c, 29c) in which the supersonic lance (12) is positioned in close proximity to the surface of the molten metal (16) and the lance (29) to deliver coal dust is positioned in the vicinity of the surface of the layer of slag (22), and a plurality of burners (28) positioned on the cooled sidewalls (31) of the furnace (10) and delivering oxygen-based gases and combustible substances, whereby at least two first burners (28) work with the action of one burner supporting the action of the next one, the furnace (10) being charged with one or more charges which provide for a first step of start-up of the melting and a second step of melting, a refining step and a tapping step being included, in which method in the first step of start-up of the melting at least one second burner (28e) collaborates in freeing quickly the path of introduction of the supersonic lance (12) and of the lance (29) to deliver coal dust.

Melting method for an electric ARC furnace with alternative sources of

Electric arc furnace with alternative sources of energy, which functions with direct current or alternating current and comprises at least one lance (12) to inject pure or combined oxygen above the bath (16) and a plurality of tuyeres (13) positioned in the hearth of the furnace (10) to inject oxygen below the bath, the tuyeres (13) being cooled by a peripheral movement of a cooling mixture consisting of at least one gas having a high cooling power (methane, butane, inert gases, etc.) and of at least one diluting gas (nitrogen, carbon dioxide), pipes (15) being included to introduce additives and powdered coal, post-combustion burners (28) possibly being comprised, the tuyeres (13) including an oxygen delivery pipe (18) having a diameter greater than 8 mm., the oxygen pressure being capable of being modulated according to the working steps, there being a constant minimum pressure of delivery. Melting operating method associated with such an electric furnace, wherein the charging operation with each single charge (skip) is divided into defined periods, with which are associated a pressure of delivery of oxygen through the tuyeres (13) and a percentage of gas having a high cooling power and proportioned to the rate of flow of the oxygen, there being a minimum pressure of delivery of oxygen in each moment of the working of the furnace (10).

Growing community of inventors

Ragogna, Italy

Corrado De Cecco