Method for melting metal material in a melting plant and relative melting plant

Patent metadata

Field	Value
Publication number	US-10801083-B2
Application number	US-201414786152-A
Country	US
Kind code	B2
Filing date	Apr 23, 2014
Priority date	Apr 23, 2013
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

Method for melting metal material in a melting plant comprising at least an electric furnace having at least a shell into which said metal material is introduced, and feed means to load said metal material into said shell, said method comprising at least a step of loading said metal material into said shell by means of said feed means, a melting step in which said metal material is melted, and a subsequent tapping step in which the molten metal material is tapped.

First claim

The invention claimed is:

1. A method for loading and melting metal material in a melting plant comprising an electric furnace having a shell into which said metal material is introduced, and feed means to load said metal material into said shell, said loading and melting method comprising:
loading said metal material into said shell by means of said feed means,
melting said metal material, and then
tapping the molten metal material,
wherein said loading comprises a first loading substep in which said metal material is loaded inside said shell to generate an initial accumulation of solid metal material inside said shell equal to between 25% and 45% of the overall quantity of molten material contained inside the electric furnace before the tapping and which will be tapped at the end of the melting cycle,
wherein the melting comprises melting a first quantity of said metal material loaded inside said shell during the first substep, and wherein said loading further comprises a second loading substep, performed subsequent to the first substep, in which the load with which said metal material is unloaded into the shell is reduced by a control device in such a way that the load of metal material that is charged into the electric furnace in said second loading substep corresponds to the first quantity of metal material that is melted, so as to maintain, inside a metal bath that is gradually formed, a quantity of solid metal material that is equal to the quantity of solid metal material that defines said initial accumulation, and
wherein said loading further comprises a third loading substep in which the feed load is further reduced until the loading process is stopped, to allow all the metal material present in the furnace to be completely melted, wherein the tapping step takes place when the whole solid mass has melted.

2. The method of claim 1 , wherein at least between and/or during said first loading substep and second loading substep an auxiliary heat energy supply is provided by combustion-type auxiliary heating energy supply means.

3. The method of claim 2 , wherein said auxiliary heating energy supply means are disposed in proximity to said accumulation of solid material in order to heat the latter.

4. The method of claim 1 , wherein said quantity of metal material that defines the accumulation comprises between 30% and 40% of the overall quantity of liquid metal that is tapped.

5. The method of claim 4 , wherein said quantity of metal material that defines the accumulation comprises between 32% and 38% of the overall quantity of liquid metal that is tapped.

6. The method of claim 1 , wherein the load in said first loading substep comprises between about 50 (kg/min)/MW and about 150 (kg/min)/MW.

7. The method of claim 6 , wherein the load in said first loading substep comprises about 100 (kg/min)/MW.

8. The method of claim 1 , wherein the load in said second loading substep is constant and comprises between 75 (kg/min)/MW and about 85 (kg/min)/MW.

9. The method of claim 1 , wherein said step of loading said metal material into said shell occurs immediately after said tapping step.

10. The method of claim 1 , including disposing said feed means at the side and above said shell, and disposing the mass of said metal material of the accumulation so that the mass of said metal material moves to a height near the feed height of said feed means.

11. The method of claim 1 , wherein during said tapping step said molten material is taken from said shell leaving inside the shell a determinate level of liquid material for a subsequent melting step, wherein the quantity of liquid material defining said level comprises between 10% and 25% of the overall quantity of liquid metal.

12. The method of claim 1 , wherein the tapping comprises rotating the shell until a level of the melted metal material in the furnace is equal to between 10% and 25% of the total quantity of melted metal material in the furnace prior to the tapping, and wherein the level of the melted metal material in the furnace is maintained following the tapping.

13. The method of claim 1 , wherein the feed means comprises a conveyor that is movable in a horizontal direction toward and away from the electric furnace.

14. A method for loading and melting metal material in a melting plant comprising an electric furnace having a shell into which said metal material is introduced, and feed means to load said metal material into said shell, said loading and melting method comprising:
loading said metal material into said shell by means of said feed means,
melting said metal material, and then
tapping the molten metal material,
wherein said loading comprises a first loading substep in which said metal material is loaded inside said shell to generate an initial accumulation of solid metal material inside said shell equal to between 25% and 45% of the overall quantity of molten material contained inside the electric furnace before the tapping and which will be tapped at the end of the melting cycle,
wherein the melting comprises melting a first quantity of said metal material loaded inside said shell during the first substep, and wherein said loading further comprises a second loading substep, performed subsequent to the first substep, in which the load with which said metal material is unloaded into the shell is reduced by a control device in such a way that the load of metal material that is charged into the electric furnace in said second loading substep corresponds to the first quantity of metal material that is melted, so as to maintain, inside a metal bath that is gradually formed, a quantity of solid metal material that is equal to the quantity of solid metal material that defines said initial accumulation,
wherein said loading further comprises a third loading substep in which the feed load is further reduced until the loading process is stopped, to allow all the metal material present in the furnace to be completely melted, wherein the tapping step takes place when the whole solid mass has melted, and
wherein the tapping comprises maintaining a level of the melted metal material in the furnace equal to between 10% and 25% of the total quantity of melted metal material in the furnace prior to the tapping.

15. The method of claim 14 , wherein the tapping further comprises rotating the shell until the level of the melted metal material in the furnace is equal to between 10% and 25% of the total quantity of melted metal material in the furnace prior to the tapping.

16. The method of claim 14 , wherein the feed means comprises a conveyor that is movable in a horizontal direction toward and away from the electric furnace.

Assignees

• Danieli Off Mecc

Inventors

• Villemin Bernard
• Wilhelm Uwe
• Narholz Thomas
• Riga Enrico

Classifications

• C21C5/527 Primary

  Charging of the electric furnace · CPC title

• F27B3/186

  Charging in a vertical chamber adjacent to the melting chamber · CPC title

• F27D11/10

  Disposition of electrodes · CPC title

• F27B3/205

  Burners · CPC title

• F27D13/002

  Preheating scrap · CPC title