JPH0892630A - Gaseous oxygen blowing device for electric furnace - Google Patents

Abstract

PURPOSE: To provide a gaseous oxygen blowing device of which the stable operation is assured by improving the utilization efficiency of oxygen, minimizing the splash of molten metal and slab and suppressing the wear of an electrode and the damage to the lance itself. CONSTITUTION: This gaseous oxygen blowing device is composed of a water or air cooled nonconsumable oxygen lance pipe 10 and a freely attachable and detachable consumable nozzle 14 mounted at the front end of this nonconsumable oxygen lance pipe 10. The gaseous oxygen is blowed in the state of immersing the consumable nozzle part at the top end part of lance pipe into the molten metal at the time of blowing of the gaseous oxygen. As a result, the utilization efficiency of oxygen is improved and the splash of the molten metal and slag is minimized. The free blowing of the gaseous oxygen into the furnace regardless of the furnace volume (furnace diameter and furnace height) is made possible while the wear of the electrode and the damage to the lance itself are suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for blowing oxygen or an oxygen-containing gas into a molten metal in an electric furnace used for melting metal materials, refining molten metal, and the like.

[0002]

2. Description of the Related Art As an electric furnace used for melting metal materials, refining molten metal, etc., it is attached to electrodes placed above the metal materials charged in the furnace and furnace walls such as the bottom and side walls of the furnace. A DC electric furnace that melts metal materials and smelts molten metal by passing an electric current between the electrodes and the three electrodes that are placed above the metallic materials charged in the furnace. An alternating current electric furnace for melting a metal material and refining a molten metal is known.

In this type of electric furnace, in order to accelerate the melting of the metal material and to refine the molten metal, a consumable pipe of oxygen is generally used to blow oxygen into the molten metal in the furnace. There is. Conventionally, an operator had to hold a pipe for blowing oxygen and powder and blow it into the furnace.
In recent years, a non-consumable water-cooled lance system, in which an upper-blown lance of a converter disclosed in Japanese Patent Application Laid-Open No. 1-219116 is applied to an electric furnace, has been adopted from a consumable pipe blowing method. Since it eliminates the need to connect a new pipe due to the exhaustion of the previous pipe, it is adopted as a method that frees the worker from the work under heavy environment and high temperature environment.

[0004]

In a converter for refining molten metal, a lance cooled with water is blown into the furnace from above, and a non-consumable lance has been put into practical use. In, the height from the surface of the bath to the opening is 1
Since it is 0 m or more, scattering of molten metal and slag does not pose a problem. However, in the electric furnace, the height up to the furnace lid is about 2 m, and when supersonic injection is performed by the non-consumable lance, the molten metal or slag is greatly scattered, resulting in poor yield and large electrode wear. , It will result in a hindrance to the operation. In order to suppress the scattering of the molten metal or slag to the extent that it does not hinder the operation, it is necessary to greatly reduce the blowing gas, and there is a problem that the required amount cannot be blown.

Therefore, in order to make up for the shortage of the blowing gas, it is necessary to increase the number of consumable lances or use a consumable pipe for blowing. An object of the present invention is to provide an oxygen gas blowing device which can be operated safely while minimizing the scattering of molten metal and slag in an electric furnace, and which dramatically improves the utilization efficiency of oxygen or oxygen-containing gas.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, oxygen or oxygen is introduced into an electric furnace for melting a metallic material, accelerating melting of a metallic material in an electric furnace used for refining a molten metal, and refining a molten metal. The structure of an oxygen blowing lance device for blowing an oxygen-containing gas is characterized by comprising a non-consumable lance pipe and a consumable nozzle at the tip of the non-consumable lance pipe that is detachable.

[0007]

In the oxygen gas blowing device according to the present invention, the water-cooling or air-cooling non-consumable lance pipe is provided with a detachable consumable nozzle at the tip thereof. The conventional non-consumable lance blows oxygen gas at a supersonic velocity from 100 mm to 500 mm above the molten metal melting surface, so that the molten metal or slag is severely scattered, resulting in not only poor yield but also a hindrance to operation. Also, the scattering of molten metal or slag mainly occurs in the furnace wall (horizontal direction) and furnace lid (upward) direction of the blowing direction, and it is not possible to increase the blowing amount (speed) of oxygen gas due to supersonic slur .

In the oxygen gas blowing device of the present invention,
When the oxygen gas is blown into the molten metal, the oxygen gas is blown while the consumable nozzle portion at the tip of the lance pipe is immersed in the molten metal, so that the molten metal or slag does not scatter, so that free oxygen blowing is possible. As described above, according to the present invention, the blowing amount and utilization efficiency of oxygen or an oxygen-containing gas can be dramatically improved, and the scattering of molten metal and slag can be minimized to operate safely.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 is a cross-sectional view of a DC electric furnace to which the present invention is applied, and FIG. 2 is an enlarged cross-sectional view of a consumable nozzle 14 at the tip of the oxygen injection lance pipe 10 of FIG. The DC electric furnace 1 shown in FIG. 1 comprises a furnace body 4 covered with a refractory 2 and a water-cooled box 3, and a furnace lid 5 arranged above the furnace body 4, which can be lifted and lowered from the center of the furnace lid 5. Between the molten metal 8 of scrap mainly charged in the DC electric furnace and the tip of the upper electrode 6 by the direct current supplied to the upper electrode 6 and the bottom electrode 7 arranged on the bottom of the furnace. The scraps are melted or the molten metal 8 is heated by the arms formed in the above.

A water-cooled oxygen lance 10 and a water-cooled lance 10 disposed below the oxygen lance 10 for cooling the molten metal 8 from the working port 9 provided in the furnace body 4 for heating and refining. A powder injection lance 11 is placed in the furnace. The lances 10 and 11 can be adjusted in position in the front-back and up-down directions in the furnace by a drive device (not shown) for moving forward and backward and up and down.

The lances 10 and 11 are held by a lance holder 12, and the lance holder 12 is supported by an arm 13. A consumable nozzle 14 that is immersed in the molten metal is attached to the tip of the water-injected non-consumable lance pipe 10 for blowing oxygen. When blowing oxygen gas into the electric furnace, as shown in FIG.
Oxygen gas is blown in while the consumable nozzle 14 at the tip of 0 is immersed in the molten metal. The oxygen blowing lance pipe 10 forms an angle θ ₁ with the surface of the molten metal. Also,
From the experimental results, the angle θ ₁ is optimally 30 ° ≦ θ ₁ ≦ 60 ° in terms of oxygen utilization efficiency and prevention of scattering of molten metal and slag.

The consumable nozzle 14 is a straight nozzle made of metal (SS400) as shown in FIG. The material of the consumable nozzle 14 may be alumina, graphite, zirconia / graphite refractory material. The consumable nozzle 14 and the tip of the non-consumable lance pipe 10 are connected by inserting a consumable nozzle into the tip of the non-consumable lance pipe as shown in FIG. 2 and connecting them with a thermosetting adhesive. Alternatively, any structure that can be freely attached and detached, such as flange fastening, may be used. When the oxygen gas is not blown into the molten metal, the consumable nozzle 14 may be attached or removed.

[0013]

As described above, by using an oxygen gas blowing lance in which a consumable nozzle is attached to the tip of the non-consumable lance pipe, the molten metal and slag are scattered when the oxygen gas is blown into the molten metal. Is kept to a minimum, and the large lump of molten metal on the lance is prevented from being constantly scattered, and oxygen is blown regardless of the furnace volume (furnace diameter, furnace height) while suppressing electrode wear and damage to the lance itself. ,
You can blow it freely. In addition, since oxygen can be blown deeply into the molten metal, the utilization efficiency of oxygen is dramatically improved, safe operation is possible, and it greatly contributes to improved productivity and reduced energy costs. Extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view of a DC electric furnace to which the present invention is applied.

FIG. 2 is an enlarged cross-sectional view of the tip of the lance pipe of FIG. 1 of the present invention.

[Explanation of symbols]

 1 DC Electric Furnace 2 Refractory 3 Water Cooling Box 4 Furnace Body 5 Furnace Lid 6 Upper Electrode 7 Furnace Bottom Electrode 8 Molten Metal 9 Working Port 10 Non-consumable Oxygen Lance Pipe 11 Powder Injection Lance 12 Lance Holder 13 Arm 14 Consumable Type nozzle

Claims (1)

[Claims] 1. A lance device for blowing oxygen or an oxygen-containing gas into an electric furnace for melting a metal material, accelerating dissolution of a metal material in an electric furnace used for refining a molten metal, and refining a molten metal. An oxygen gas blowing device for an electric furnace, characterized in that it comprises a non-consumable lance pipe and a consumable nozzle detachably attached to a tip of the non-consumable lance pipe.