JPH0665950B2 - Charging method for raw materials such as arc furnace scraps - Google Patents

Description

TECHNICAL FIELD The present invention relates to a raw material charging method for scraps and the like for charging raw materials such as scraps into an arc furnace.

[Prior Art] Conventionally, for example, when scrap is charged into an arc furnace, the scrap is simply put into the arc furnace from a scrap bucket located right above the arc furnace. In other words, no particular consideration was given to the charging position of scrap in the arc furnace. In addition, when charging scrap, the power supply to the arc furnace was temporarily stopped, the furnace lid was opened, and then the scrap was charged in batches by a bucket.

[Problems to be Solved by the Invention] Conventionally, since raw materials such as scrap are simply dropped into an arc furnace in a lump, the portion facing the electrode in the arc furnace becomes a so-called hot spot portion and scrap. Melts rapidly and the heat loss from the furnace wall at the hot spot becomes large. Further, the wear of the furnace wall at the hot spot portion is severe, which is one of the factors that hinder the durability of the arc furnace body.

However, batch-type scrap charging inherently has the following problems. That is, the operation rate of the arc furnace is lowered because the power input is temporarily stopped at the time of charging the scrap, and the furnace lid is opened each time the scrap is charged, which causes a large heat loss.

The present invention solves such a conventional problem and enables the continuous charging system of raw materials such as scrap to be adopted.

[Means for Solving the Problems] The present invention is intended to concentrate the raw material such as scrap into the hot spot portion facing the electrode in the furnace body, and to feed the raw material to the hot spot portion and the cold adjacent to the hot spot portion. It is characterized in that it is charged along the circumferential direction of the furnace body from the boundary portion with the spot portion toward the hot spot portion side.

[Operation] According to the raw material charging method for scrap or the like of the arc furnace of the present invention, the raw material is charged from the boundary portion between the hot spot portion and the cold spot portion toward the hot spot portion along the circumferential direction of the furnace body. By doing so, the raw material is not only intensively charged into the hot spot part, but also the charged raw material is distributed so as to be distributed along the circumferential direction of the furnace body and spread over the entire hot spot part. It Then, the raw material charged in the entire hot spot portion in this way covers the entire hot spot portion without a gap, and prevents a large heat loss from the furnace wall in the hot spot portion, and the furnace in the hot spot portion. Protect the wall and prevent its wear.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
In this example, scraps that are finely cut are handled as scraps to be charged into the arc furnace.

First, a device configuration for carrying out the present invention will be described.

In the figure, reference numeral 1 is an arc furnace, which has a furnace lid 3 on an upper portion of a furnace body 2 made of a refractory material. This furnace lid 3
The arc furnace 1 is opened by turning to the position shown by the chain double-dashed line in FIG. An electrode 4 is located in the arc furnace 1. In this example, three electrodes 4 are provided, and these are pulled up when the furnace lid 3 turns. As shown by the dotted line in FIG. 1, in the arc furnace 1, the three locations where the electrodes 4 face each other are hot spots P ₁ , and the locations between these hot spots P ₁ are cold spots. It becomes part P ₂ . The furnace lid 3 is provided with an elbow 5 for discharging the exhaust gas in the arc furnace 1. Furnace body 2 located above the boundary portion between the hot spot portion P ₁ and the cold spot portion P ₂
A total of three scrap charging ports 6 are provided in the furnace wall portion of the. A charging duct 8 for the scrap S is connected to each charging port 6 via a separation flange 7, and the scrap S is passed through the charging duct 8 as shown in FIG.
From the boundary portion between the hot spot portion P ₁ and the cold spot portion P ₂ toward the hot spot portion P ₁ side,
It is designed to be inserted along the circumferential direction of. The hotspot portion P located on the right side in FIG.
_Although illustration of a charging duct for charging the scrap S to ₁ is omitted, the charging duct is similar to the other two charging ducts 8 shown on the left side, and the hot spot P _The scrap S is provided so as to be introduced along the circumferential direction of the furnace body 2 from the boundary portion between ₁ and the cold spot portion P ₂ . The separation flange 7 separates when the arc furnace 1 tilts and the molten steel therein is poured out. A scrap receiving hopper 9 is provided above the charging duct 8. In the case of this example, one common receiving hopper 9 is provided for the two charging ducts 8 on the right side in FIG. 1, and two charging ducts are diverged from this one receiving hopper 9. 8 in a row. Stop valves 10 are provided at those branch points. Above the receiving hopper 9, the unloading side of the horizontal conveyor 11 for scrap transportation is located. The horizontal conveyor 11 conveys scrap S that has been finely cut, and its peripheral portion is covered with a conveyor cover 12.

Next, the operation of the apparatus configured as described above and the scrap charging method according to the present invention will be described.

The horizontal conveyor 11 continuously carries out the scrap S from the external scrap carrying-out place, and inputs it into the receiving hopper 9. The scrap S is a product in which scraps of various sizes are finely cut in advance by a scrap shear and sized. Therefore, as the horizontal conveyor 11, a general conveyor can be used. The scrap S in the receiving hopper 9 is opened by opening the stop valve 10.
Electric arc furnace 1 from scrap charging port 6 via charging duct 8
It is continuously charged inside. As a result, the scrap S is not only intensively charged into the three hot spots P ₁ , but also scraped in the circumferential direction of the furnace body 2 because the scrap S is charged along the circumferential direction of the furnace body 2. Therefore, the scrap S is charged so as to spread over the entire hotspot portion P ₁ . And
Such scrap S which is loaded in the always cover the entire respective hot spot portion P _1, while preventing a significant heat loss from the furnace wall at the hot spot portion P _1,
The furnace wall in the hot spot portion P ₁ is protected.

By the way, by equipping the furnace wall of the arc furnace 1 with a sensor (not shown) for detecting the degree of melting of the scrap S in the furnace, and controlling the conveying speed of the scrap S based on the detection signal of the sensor. It is possible to realize the optimum melting by matching the charging speed of the scrap S and the melting speed of the scrap S. As a sensor in that case, it is possible to use a sensor (for example, a thermocouple) that detects a temperature change of the furnace wall when the scrap S before melting exists near the furnace wall and when it disappears. it can.

Further, in the present embodiment, since the charged scrap S always covers the furnace wall of the hot spot portion P ₁ , the continuous charging method of scrap is adopted without any trouble. This is extremely advantageous in the following points. That is, since the scrap S is continuously charged without opening the furnace lid 3, heat loss from the furnace is small. In addition, since there is no time to stop the power supply to the arc furnace 1, the maximum power of the transformer can be continuously supplied. As a result, the steelmaking time can be shortened, productivity can be improved, and the basic unit of power, electrodes, and bricks can be kept small, and the cost can be significantly reduced by labor saving and unmanned charging. it can. Moreover, since the sized scrap S is charged, the heat transfer efficiency to the scrap S is good and the melting speed is fast, and the batch type charging of the scrap S is performed for continuous transfer of the scrap S by the conveyor. No need for a large scrap charging overhead crane.

Further, in the above-described embodiment, the scrap S is charged through the charging port 6 formed in the furnace wall, but the charging port for the scrap S may be provided in other portions such as the furnace lid 3 and, in short, scrap In order to concentrate the raw material such as S in the hot spot portion P ₁ and to charge the hot spot portion P ₁ so as to spread over the entire hot spot portion P ₁ , the raw material is hot from the boundary portion between the hot spot portion P ₁ and the cold spot portion P _2. It suffices if it is at a position where it can be charged along the circumferential direction of the furnace body 2 toward the spot portion P ₁ side.

[Effects of the Invention] As described above, according to the method for charging raw material such as scrap in the arc furnace of the present invention, the raw material is moved from the boundary portion between the hot spot portion and the cold spot portion adjacent thereto to the hot spot portion side. By pouring it along the circumferential direction of the furnace body, the raw material is concentrated in the hot spot part,
Moreover, it is possible to insert the hot spot so that it covers the entire hot spot. Therefore, the entire hot spot is always covered with raw materials such as scrap to prevent large heat loss from the furnace wall in the hot spot. In addition to preventing it, it is possible to protect the furnace wall in the hot spot part and prevent its wear.

In addition, this makes it possible to employ a continuous charging method that is superior to the batch charging method for raw materials such as scraps, and avoids problems in adopting the continuous charging method.

[Brief description of drawings]

1 is a plan view, FIG. 2 is a longitudinal sectional view, and FIG. 3 is a view on arrow III in FIG. 2. 1 ... Arc furnace, 2 ... Furnace body, 3 ... Furnace lid, 4 ... Electrode, 6 ... Scrap charging port, 8 ... Charging duct, 11 ...
… Conveyor, S …… Scrap (raw material), P ₁ …… Hot spot part, P ₂ …… Cold spot part.

Claims (2)

[Claims] 1. A raw material charging method for charging a raw material such as scrap into a furnace body of an arc furnace, wherein the raw material is charged in a concentrated manner at a hot spot portion facing an electrode in the furnace body. A method for charging raw material such as scrap in an arc furnace, characterized by charging along the circumferential direction of the furnace body from the boundary between the hot spot part and the cold spot part adjacent to the hot spot part toward the hot spot part side . 2. The method for charging a raw material for scrap or the like in an arc furnace according to claim 1, wherein raw materials such as finely crushed scrap are continuously charged.