JPS6153136A - Reformation of steel slag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention adds a modifying material to steelmaking slag (hereinafter referred to as slag) to modify its mineral composition and thereby prevent the expansion and collapse of the slag. It's about how to do it.

[Prior art]

mm steel slag is 2CaO・5iOt, F・CaO2
F-M [(○, 2CaO-Few Os, 4C
aO-Alz Ox ・Fe! o2, Fe
d5 Fe! It mainly contains Os, Fex O4, etc., but 2Cab-3ift contains r-2Ca during the cooling process.
The steelmaking slag expands and collapses due to the volumetric expansion when F-CaO and F-MgO absorb water and change to Ca(OH)z and Mg(OH)z. For this reason, cement raw materials (CaO, SI Ox, F
Steelmaking slag cannot be used as a civil engineering material as it is, except when used as fertilizer, etc.), so most of it was disposed of in landfills, but as is well known, molten MiZl slag Modifiers such as silicate rocks, minerals or weathered products thereof, coal ash, foundry waste sand, karami, glass chips, red dirt, etc. are added to the steelmaking slag to stabilize it so that it does not expand and collapse as described above. (hereinafter, this reaction is referred to as a slag reforming reaction).

There are two ways to add this reforming material; one is to put it into the steelmaking furnace, and the other is to put it into a slag pan (commonly known as
However, since the method of charging the reforming material into the J14 furnace may cause damage to the furnace wall of the steelmaking furnace, generally, it is The method used is to input materials.

Basically, there are two ways to introduce the reforming material into this slag ladle: (a) A method in which it is introduced in contact with the slag flow discharged from the steelmaking furnace; (b) A method in which it is injected in contact with the slag flow discharged from the nil steel furnace. (c) A method in which the slag is used as a substitute for the slag in the slag pan and is placed in the slag pan before receiving the slag (hereinafter referred to as the slag method) (
d) (There is a method of putting the slag into a sandwich-like formation with the slag in a pot.

[Problem that the invention seeks to solve]

However, in any of the above methods of charging the reforming material into the steelmaking furnace, or the methods (a), (b), and (d) above, the reforming material is placed inside the steelmaking furnace or in a 1 liter slag pot. Therefore, a device is required to shape the reforming material into a predetermined shape and introduce it into a high-temperature steelmaking furnace or slag pan, and therefore the method is not simple.

In comparison, the method (c) in which the reforming material is used as a substitute for the slag in the slag pan and is placed in the slag pan before receiving the slag, is a method in which the modifier is shaped into a predetermined shape and heated to a high temperature. It is an extremely excellent method because it does not require a device to put the reforming material into the steelmaking furnace or the slag pot, and it can be done while the slag pot is cold. It can be said.

However, since the modifying material is at the bottom of the slag pan and the modifying material is in contact with the steel shell, the modifying material and slag are not mixed sufficiently. There was a drawback that the reaction was not carried out sufficiently. Therefore, in combination with the above method, a lance pipe is inserted into the slag pan and bubbling gas (0!, Nt, air) is blown in to stir the slag.
The slag was modified, but even with this method, it was not possible to completely modify the slag.
Instead of the lance pipe, there is a method of mechanically stirring the slag by inserting an impeller-like object into the hot slag, but this method requires complicated equipment and is not practical because the slag adheres to the impeller, making stirring impossible.

The present invention has been made in view of the above circumstances, and improves the slag slag method described in (c) above, which is simple, and further promotes the slag reforming reaction and improves steelmaking slag by completely reforming the slag. The purpose is to provide a quality method.

Means for Solving the Problem c] The method for modifying steelmaking slag according to the present invention in accordance with the above object is as follows:
In a steelmaking slag reforming method in which a reforming material is placed in a slag pan in advance to receive molten steelmaking slag from a steelmaking furnace and the steelmaking slag is reformed, wood chips are added together with the above-mentioned reforming material. It is composed of:

Here, the modified material refers to silicate minerals, rocks or their weathered products, coal ash, foundry waste sand, karami, glass waste, red stain, etc., and the wood chips are made by cutting wood into appropriate sizes. In addition to objects, this also includes wood chips, wood chips, the remains of packaging boxes, etc.

[Effect]

In the present invention, a modifier and wood chips are placed in advance as sludge in a sludge discharging pot before receiving sludge. Therefore, when molten slag from a steelmaking furnace is put into the slag pan, the wood chips are exposed to high temperatures and gasify, and since the wood chips are light, some of them try to float on top of the slag. With gasification and floating of wood chips,
The reforming material and slag are stirred to promote the slag reforming reaction. For this reason, it is preferable to place the wood chips in the lower part of the modification material.

Also, in this way, the slag is not contaminated by wood chips, since the wood chips placed in the slag pan are burned and leave no harmful substances in the slag.

[Experiment 1] In order to confirm the effect of the method for reforming steelmaking slag according to the present invention, the following experiment was conducted using slag in the reduction stage of electric furnace No. 40 (which has the property of collapsing when cooled as it is).

The outline of this experimental apparatus is shown in Figure 11E-Figure 4, and the following four methods (a), (b), (c), and (d) are all
Take the molten slag 1 from the electric furnace into the ladle 2 and pour it into this? 8 slag 1
(3 to 4 t/1ch) to the specified modifying material (particle size 5mm
Hereinafter, this was carried out by putting 600 to 750 kg/1ch) 3 into a waste pan (commonly referred to as a slag pan) 4.

(b) As shown in Figure 1, a predetermined amount of reforming material 3 is placed in the slag pan 4.
I experimented by adding only

As a result, the unreacted residue of the modification material 3 was about 70 to 80%.
there were. Some of the slag had been reformed, but others had collapsed.

(b) As shown in Figure 2, a predetermined amount of reforming material 3 is placed in the slag pan 4.
and air bubbling with lance pipe (size 20A) 5 (conditions: 2m37m1n, 1~
1.5 kg/am”).

As a result, the unreacted residue of the modification material 3 was about 30 to 40%.
there were. Some of the slag had been reformed, but others had collapsed.

(c) As shown in Figure 3, a piece of wood (approximately 8 to 10 cm in diameter,
The modifying material was spread on top of 3 pieces (3 pieces with a length of 30 c+s) 6.

As a result, the unreacted residue of the modifying material 3 was approximately 0 to 5%. The slag was very good (modified).

(d) As shown in Figure 4, a piece of wood (approximately 8 to 10 ell in diameter)
, 3 pieces with a length of 30 cva) 6), and then air bubbling with a lance pipe (size 20 A) 5 (conditions: 2 m37 m1n, 1~1°5)
kg/cm”).

The results showed that there was almost no unreacted residue of the modifying material 3, and the slag was very well modified.

From the above, it can be seen that if the modifying material is placed on a piece of wood, the modification of the steelmaking slag is almost completely carried out [Experiment 2]. The following experiment was carried out regarding the case of a two-charge receiver in which slag 1a and 1b were introduced twice after a certain period of time.

The outline of this experimental apparatus is shown in Fig. 5, but the difference from the above experiment 1 is that the slag 1a and 1b are charged in two sides at a certain time,
- The modification material 3, etc., was salined in advance each time it was added.

(a) When only the modifier 3 was placed as shown in FIG. 5, approximately 70 to 80% of the modifier remained unreacted, and the slag was almost unmodified.

(b) In addition to the above (a), air bubbling (the conditions are as described above) was also used using a lance pipe (not shown). The results showed that there was about 20 to 30% of the unreacted modifier as a whole, and some of the slag was modified while the rest was unmodified.

(c) As shown in FIG. 6, a piece of wood 6 was placed under each modified material 3. The results show that the unreacted modifier is 0 to 5.
%, the slag was very well modified.

From the above experiments, it can be seen that if the modifying material 3 is spread over the wood chips 6, extremely excellent modification of the slag can be achieved.

Next, the components and properties of various slags will be compared between the conventional slag method and the method according to the present invention shown in Example 1.2 below.

First, Example 1.2 will be explained.

[Example 1] A piece of wood (approximately 10e in diameter) was placed in the slag pot.
s of about 30cm in length), put the reforming material (530kg/1ch) on top of it, and added 2 charges of slag (3.5t/1ch) discharged from the electric furnace. (Indicated by slag C in the table).

[Example 2] Place wood pieces (4 pieces with a diameter of about 10 cm and a length of about 30 cm) in a slag pot, and place the modifying material (600 kg/1ch) on top of them.
and 100 to the slag discharged from the converter (6t/1
Table 1 shows the chemical analysis (direct (wt%)) of the modifying material.

Table 1 Chemical analysis values of the used modifier (wt%) Table 2 also shows the chemical analysis values of various slags, decay rates, and minerals determined by X-ray diffraction. Here, the disintegration rate is determined by crushing the cooled slag after treatment (25 mm or less) and magnetic separation.
Autoclaving (AS) for ~25mm slag
TM method, 200℃, 20atm, held for 3 hours), 10m
+n and below were calculated by taking into consideration decay materials.

For comparison, the properties of slag (indicated by A and B in the table) that were modified by the slag method are also shown.

Next, Table 3 shows the results of the elution test according to the method notified by the Environment Agency and the aggregate test according to JI37.
1.

〔Effect of the invention〕

As described above, the present invention is an improvement on the number 7' method, in which wood chips are placed in advance together with a modifying material before receiving the slag, and the gas generated from the wood chips and some of the wood chips float to the surface. Since the slag is stirred and the slag reforming reaction is promoted, almost complete reforming of the slag can be carried out, and the method of the present invention does not require any special tools or equipment, so it is simple and easy to use. It has become possible to sufficiently modify slag using an inexpensive method, and it has become possible to use slag more widely.

[Brief explanation of the drawing]

Figures 1, 2, and 5 are side sectional views of an apparatus used for experimenting with a conventional method for reforming steelmaking slag, and Figures 3, 4, and 6 are views of an embodiment of the present invention. FIG. 2 is a side sectional view of an apparatus used for experimenting with such a steelmaking slag reforming method. [Explanation of symbols] 1, la, lb -----m slag, 2---
- Ladle, 3 -...- modified St material, 4-...-
Slag pot, 5 -------...Lance pipe, 6-
...-piece of wood

Claims (2)

[Claims] (1) In a steelmaking slag reforming method in which a reforming material is placed in a slag pan in advance to receive molten steelmaking slag from a steelmaking furnace and the steelmaking slag is reformed, together with the above reforming material. A method for modifying steelmaking slag characterized by adding wood chips. (2) The method for modifying steelmaking slag according to claim 1, wherein the wood chips are arranged under the modifying material.