JPS59153819A - Method for burning carbonaceous solid in melting and refining furnace - Google Patents

Abstract

PURPOSE:To burn well carbon and to improve refining efficiency when refining is carried out in a melting furnace by burning a carbonaceous solid, by blowing an oxidizing gas on the peripheral part of the surface of a bath under whirling or in the direction of an oblique tangential line. CONSTITUTION:When molten metal in a furnace is refined by charging a carbonaceous solid and blowing an oxidizing gas rich with oxygen, the carbonaceous solid is usually mixed with slag, and indirect refining is carried out. At this time, the oxidizing gas is blown form a pair of lances on the peripheral part of the surface of the bath under whirling or in the direction of an oblique tangential line. The charged carbonaceous solid is uniformly dispersed, and uniform oxidation proceeds, with refining efficiency improved.

Description

Detailed Description of the Invention This invention involves adding a carbonaceous solid such as coke onto a molten metal or molten slag bath, and blowing an oxidizing gas such as oxygen from above to burn the carbonaceous solid. This invention relates to a method for burning carbonaceous solids in a metal refining method that utilizes heat for melting raw materials and refining reactions.

A carbonaceous solid such as coke is added to the molten slag containing the molten oxide, and an oxidizing gas is blown onto it to eliminate the heat generated by combustion of the carbonaceous solid, dissolve the oxide, and The method of supplying thermal energy for reduction is
It is important as the basic norocess principle for carrying out melt reduction of iron ore and chromium ore with carbonaceous solids.

However, by adding granular coke to the molten slag, the oxidizing gas spray nozzle inserted from the top of the furnace
The problem with coke combustion is that the coke tends to be blown toward the furnace wall by the kinetic energy of the gas and collect near the furnace wall or near the stagnation point between the jets. The contact efficiency between the oxidizing gas blown onto the coke grains is poor, and the oxidizing gas only comes into contact with the slag bath, which significantly reduces the oxygen utilization efficiency. Relatively expensive ^(
Since 5 gas is often used, it can easily become a big problem.

Of course, since a small amount of molten slag is suspended above the molten metal containing carbon, the oxidizing gas blown onto the metal can pass through the slag bath and react with the carbon in the molten metal. However, in processes aimed at melting and reducing oxides, the slag bath is generally very important, and oxidizing gas is often passed through the slag bath.

Therefore, a major issue is how to improve the contact efficiency between the suspended carbonaceous solid and the σλ-oxidizing gas.

In a test experiment concerning a method of blowing oxidizing gas onto coke grains suspended in a large amount of slag bath to burn them, the present invention was conducted to avoid the above-mentioned blowing phenomenon of one coke being blown away due to the kinetic energy of the gas. Based on the knowledge that this is the most important factor in improving the efficiency of oxygen utilization, the method of spraying oxidizing gas was devised to avoid this "blowing phenomenon". .

The oxidizing gas blowing methods described in claims (1), (2), and (3) all prevent a decrease in the utilization efficiency of oxidizing gas due to such a single coke blowing phenomenon. This is an effective method.

The details of the present invention will be explained below based on the drawings.

The method according to claim (2) is a method in which oxidizing gas is sprayed using a rotating lance. As shown in Fig. 1, molten slag 3 containing oxides such as Fe and Or is collected in a furnace body 1 lined with a refractory, and is reduced by coke grains 4 floating in the slag. The molten metal is stored in the furnace bottom 2. Raw materials and coke are continuously fed to the sheet 8 on the furnace. In oxygen spraying, coke is combusted by the oxidizing gas blown into the Sinulag bath by lance 5, and the heat generated causes the dissolution of oxides and
Heat of reduction is supplied. The method shown in FIG. 10 has a lance grasping mechanism 7 on the central axis, and the lance 5 is grasped so as to be inclined with respect to the central axis. By rotating the inclined lance 5, the slag of the oxidizing gas rotates in the circumferential direction on the surface of the slag bath, which is the collision surface with the bath.

On the other hand, in the method shown in FIG. 1(b), the lance 5 is upright with respect to the central axis of the furnace, but the grasping mechanism 7 and the lance itself are rotated in the circumferential direction at a position deviating from the central axis by an appropriate distance. , the collision surface of the oxidizing gas turns in the circumferential direction, and the first
This produces an effect similar to the method in Figures (,).

If Obu is rotated at a certain speed in this way, the oxidizing gas collision surface will move faster than the moving speed of the coke grains that are trying to escape from the multi-oxidant gas collision surface due to "blowing". , oxidizing gas can be sprayed under conditions where there are always enough coke grains.In the example shown in Figure 1, one lance is used to rotate, but the same effect can be achieved by rotating multiple lances. The effect of this can be obtained.

The method according to claim (3) uses the kinetic energy of an oxidizing gas jet blown in a tangential direction.
This method aims to improve the contact efficiency between carbonaceous solids and oxidizing gas by rotating the slag bath and coke grains in the circumferential direction of the furnace.

As shown in FIG. 2, one or more inclined lances 1
In step 5, oxygen is blown into the slag bath. Due to this oxygen gas, the slag bath 13 and the coke grains 14 swirl in the circumferential direction of the furnace and pass through the oxidizing gas impingement surface 17 at regular intervals.

This maintains sufficient contact between the coke grains and the oxidizing gas. In this method, it is advantageous to convert the kinetic energy of the oxidizing ff jet into swirling motion of the bath as efficiently as possible.

For this purpose, the inclination angle 18 (angle with the bath surface) of the lance must be 60° or less, and the lance must be placed as close to parallel (tangential) to the circumference of the furnace as possible. desirable.

In this way, the spraying of oxidizing gas is determined by the location (flame point) and
By displacing the suspended carbonaceous solids relative to each other,
can significantly increase the chances of contact between oxygen and carbonaceous solids,
The effective rate of oxygen can be increased.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show one embodiment of the present invention.
FIG. 2(a) is a plan view showing another embodiment of the present invention, and FIG. 2(b) is a front view thereof. 1: Furnace body, 2: Molten metal bath, 3: Molten slag bath, 4: Floating coke, 5: Oxygen blowing slag, 6: Position of oxygen blowing lance after rotation, 7: Lance grasping mechanism, 8: Raw material sheet, 11: Furnace body, 12: Molten metal bath, 13: Molten slag bath, 14: Floating coke, 15: Inclined lance, 16: Raw material chute, 17: Impingement surface of oxygen jet, 18: Inclination angle θ of lance.

Claims (3)

[Claims] (1) Carbonaceous solids are added to the upper part of the molten metal or molten slag bath, and the carbonaceous solids are combusted by blowing oxygen or oxygen-containing gas (oxidizing gas) to the upper part, and the heat of combustion is used to convert the raw material In a furnace for melting and refining carbonaceous solids, the oxidizing gas is sprayed at the periphery of the bath surface, and the oxidizing gas is sprayed to relatively displace the position and the carbonaceous solid.・Combustion method of carbonaceous solids in smelting furnace・ (2) The method of spraying the oxidizing gas is such that the means for relatively displacing the position and the carbonaceous solid is rotating the nozzle in the circumferential direction of the furnace. Method. (3) The means for displacing the position and the carbonaceous solid relative to the spraying of the oxidizing gas is such that the axis of the oxidizing gas jet is within 60° to the bath surface and has a tangential component to the periphery of the bath surface. 2. The method according to claim 1, wherein the oxidizing gas is sprayed by tilting a nozzle and displacing the suspended carbonaceous solids in the circumferential direction of the furnace by spraying the oxidizing gas.