Melting furnace for metallurgical plant and operating method therefor

Patent metadata

Field	Value
Publication number	US-11390927-B2
Application number	US-201816772385-A
Country	US
Kind code	B2
Filing date	Dec 14, 2018
Priority date	Dec 15, 2017
Publication date	Jul 19, 2022
Grant date	Jul 19, 2022

Abstract

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.

First claim

The invention claimed is:

1. An operating method of a melting furnace comprising
a vessel provided with a bottom;
a tapping duct passing through the bottom and having a first stretch arranged in a thickness of the bottom and completely passing through the bottom, and a second stretch, adjacent to the first stretch, protruding inside the vessel;
a fixed cover of the second stretch shaped as a bell, closed at an upper end thereof and open at a lower end thereof; said bell 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 fixed cover, in cooperation with the second stretch of the tapping duct, defines a volume inside the fixed cover and adapted to act as a tapping hood;
rotation means adapted 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;
the method comprising the following steps:
a) providing the vessel with the tapping duct in the first reference position and providing a bath of molten metal material at an equal level both inside and outside the fixed cover and comprised between the lower end of the fixed cover and an upper edge of the second stretch, a slag being kept on a surface of said bath outside the fixed cover;
b) rotating the vessel in a first direction so that the tapping duct passes from said first reference position to said second position inclined until the level of molten metal material reaches the upper edge of the second stretch so that the molten metal material begins to be tapped through the tapping duct creating a depression inside the volume;
c) rotating the vessel in a second direction, opposite the first direction, so that the tapping duct returns to the first reference position, while, due to said depression, the molten metal material passes from the outside of the fixed cover to the inside of the volume and continues to be tapped through the tapping duct until said depression is canceled.

2. The method according to claim 1 , wherein in step c) said depression is canceled when the level of molten metal material outside the fixed cover reaches a lower edge of the lower end of the fixed cover, whereby, at a passage of air from the outside of the fixed cover to the inside of the volume, the level of molten metal material inside the fixed cover is lowered, reaching the lower edge, and therefore reaching the level of the molten metal material outside the fixed cover;
or wherein said depression is canceled by operating a relief valve provided on the fixed cover;
or wherein said depression is canceled by further rotating the vessel in said second direction, so that the tapping duct passes from said first reference position to a third position inclined with respect to said first reference position until the level of molten metal material inside the volume reaches the lower edge of the fixed cover.

3. The method according to claim 1 , wherein, following step c), with the tapping duct in the first reference position, there are provided the steps of:
returning the bath of molten metal material to a level between the lower end of the fixed cover and the upper edge of the second stretch;
repeating steps b) and c).

4. The method according to claim 1 , wherein during at least steps b) and c) it is possible to load and/or melt scrap inside the vessel, also during the tapping.

5. The method according to claim 1 , wherein the tapping duct is always kept open, also during the melting of scrap inside the vessel.

Assignees

• Danieli Off Mecc

Inventors

• Terlicher Stefano
• D'Odorico Mattia
• Sansa Michael

Classifications

• C21C5/4653 Primary

  Tapholes; Opening or plugging thereof · CPC title

• F27B3/19 Primary

  Arrangements of devices for discharging · CPC title

• F27B3/065

  tiltable · CPC title

• C21C5/527

  Charging of the electric furnace · CPC title

• F27D3/1509

  Tapping equipment · CPC title