JPH09268036A - Annealed blast furnace slag having low sulfur concentration and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an annealed blast furnace slag having low sulfur concentrations by bringing an annealed blast furnace slag controlled in the granule size into contact with a gas containing steam in specific conditions. SOLUTION: A gas containing steam in a concentration of 15-540vol.% and heated to >=70 deg.C is blown at a flow speed of 0.03-30m/min on an annealed blast furnace slag controlled to a granule size of >=25mm and having a reducing sulfur concentration of approximately 0.3wt.% and a whole sulfur concentration of approximately 1wt.% to obtain the annealed blast furnace slag having low sulfur concentrations comprising a reducing sulfur concentration of >=0.1wt.% and a whole sulfur concentration of >=0.5wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a glass fiber raw material,
The present invention relates to a low-sulfur concentration blast furnace slowly cooled slag used as a substitute for a sheet glass raw material, an autoclaved building material (calcium silicate-based building material) raw material, and a method for producing the same.

[0002]

BACKGROUND ART Blast furnace slag and slowly cooled blast furnace slag, because it contains SiO _2, Al ₂ O _3, etc., alternative pyrophyllite clay is a glass fiber material or sheet glass material, xonotlite type or tobermorite building materials It is suitable as a substitute for minerals that have been conventionally used in many fields, such as the substitution of silica stone, which is the raw material of.

JP-A-53-72035 discloses that sulfide or S in blast furnace slag is oxidized by air or the like to a sulfur oxide salt such as thiosulfate, which is easily dissolved in water. The method of removing S in the slag is disclosed. JP-A-53-22523 discloses a method of 150
A method is disclosed in which steam is blown into the molten blast furnace slag at about 0 ° C. to react and remove S as SO ₂ and H ₂ S.

Further, JP-A-53-19337 discloses that
A method is disclosed in which lump slag obtained by solidifying blast furnace slag is brought into contact with hot water or steam to elute S in slag. However, in all of the above methods, blast furnace slag is used as a roadbed material.
In particular, the content of reducing S is 0.1 which is the target of the present invention.
Greater than wt% or less. For example, 3 blast furnace slowly cooled slags
Even if it reacts with atmospheric oxygen or the like for more than a month, only about 30% of S and S ^2- contained in slag can be stabilized as SO ₄ ^2- . In addition, JP-A-53-72
In the example of Japanese Patent No. 035, it takes 10 days for the absorbance, which is a measure of the S content, to decrease by 70%, and it takes 30 days for the decrease to saturate. JP-A-53-22
In the method disclosed in Japanese Patent No. 523, 20.9% in 5 minutes
Although it is described that the desulfurization rate can be obtained, the device for blowing the steam into the molten slag is large-scale and is industrially unsuitable because it is dangerous. Also, JP-A-53-
Japanese Patent Laid-Open No. 19337 exemplifies a case of treatment with hot water at 90 ° C., but SO ₄ ^{2− in the} treated water has an analysis value of 350 p.
There is only pm. That is, it is disclosed that the above-mentioned treatment reduces S to the extent that it can be used as a roadbed material. However, as to how much the contents of S and reducing S in the slag are actually reduced by these treatments, It is not described, and according to these conventional techniques, it was practically difficult to industrially reduce the total S to 0.5 wt% or less and the reducing S to 0.1 wt% or less.

[0005]

During the production of glass fiber, the blast furnace slow-cooling slag contains reducing S (S ⁰ and S ²⁻ ), which binds with heavy metals and causes yarn breakage. . Further, when the total S concentration is high in the production of glass fiber or sheet glass, bubbles are generated in the bath during melting, so the heat transfer for melting is lowered. Further, if the total S concentration is high, in the case of a building material that requires autoclave treatment, H ₂ S and SOx are generated from the slag during autoclave treatment, which causes an offensive odor and causes corrosion inside the autoclave. As described above, in effectively using slag, it often becomes a hindrance to practical use.
It is rarely used as a raw material for sheet glass and a raw material for autoclaved construction materials.

[0006] The present invention can be used as a substitute for the wax stone clay, which is a raw material for glass fiber or plate glass, and a substitute for silica stone, which is a raw material for zonotolite-based or tobermorite-based building materials. An object is to provide a cold slag and a method for manufacturing the same.

[0007]

In order to solve the above problems, (1) the concentration of reducing S (S ⁰ + S ^{2 −} ) that causes yarn breakage during glass fiber production is low, (2) The use of slag having a low total S concentration as a raw material which causes bubbles during glass fiber or plate glass production and H2 ₊ S and SOx generation during autoclave construction material production. S ⁰ refers to elemental sulfur (free sulfur), and S ²⁻ refers to S divalent sulfides such as CaS, K ₂ S and MnS.

The following method is known as a method for reducing the S ⁰ ₊ , S ^2- , and total S concentrations. (A) Natural Aging Treatment Method This method is "Characteristics and Utilization of Steel Slag", P104-1.
17, after crushing the blast furnace slowly cooled slag and adjusting the grain size, as shown in Japan Iron and Steel Institute (1982)
S ⁰ by stacking and reacting with oxygen in the atmosphere
And S ²⁻ are stabilized as SO ₄ ²⁻ . (B) Method of contacting with hot water or steam This method involves contacting a lump slag obtained by solidifying molten blast furnace slag with hot water or steam, as disclosed in JP-A-53-19337. Is a method of eluting the easily eluting component in the slag.

[0009] However, in the natural aging process method, even when reacted with oxygen or the like of the slowly cooled blast furnace slag 3 months or more in air, S ⁰ and S ^2- about 30 wt% only SO ₄ ^{2 -} stabilized as ₊ I can't do it, and all S
Since the concentration hardly decreases, glass fiber raw materials,
When used as a sheet glass raw material or an autoclave-processed building material raw material, the above-mentioned problems occur.

In the method of contacting with hot water or steam,
Although the generation of yellow water, which is a problem when using blast furnace slowly cooled slag as a roadbed material, can be prevented, S ⁰ , S ^2- , and total S concentration are not mentioned, and glass fiber raw material, sheet glass raw material, autoclave It is unclear whether it can be used as a raw material for treated building materials. In view of the above circumstances, the present invention is directed to reducing S (S ⁰ +
S ²⁻ ) concentration is 0.1 wt% or less, and the total S concentration is 0.
A blast furnace slowly cooled slag having a low sulfur concentration of 5 wt% or less and a method for producing the same.

The present invention was made based on the following technical idea. That is, as disclosed in the prior art, S contained in the vicinity of the surface of the slag comes into contact with water and is dissolved as soluble S ions. However, even if the slag is porous, S in the slag is difficult to be eluted due to insufficient water flow in each slag particle, and the residual S amount is large. In the case of the steam treatment, the steam comes into contact with the slag to form condensed water, and S is eluted and treated in the condensed water, so that the result is the same as the above hot water.

Based on the above-mentioned prior art, the present inventors have studied various means for effectively removing S in the slag and easily on an industrial scale. As a result, S is eluted into water as an ion. H ₂ S or S
The present invention is based on the idea that it can be volatilized and removed as a gas such as Ox. That is, since the viscosity of gas is extremely small unlike water, it is possible to easily flow out from the pores in the slag particles to the outside as long as the gas flow is given, and the residual S can be greatly reduced as compared with the conventional case. You can do it. The reason why the gas containing 15 to 50% by volume of water vapor is used here is that if the water vapor is less than 15% by volume, the amount of H ₂ O reacted with S becomes insufficient and S cannot be effectively removed. This is because when the content is more than the volume%, the water vapor condenses and stays in the pores in the slag particles, and S cannot be effectively removed for the reason described above.

The reason why the temperature of the gas containing water vapor is set to 70 ° C. or higher is that the effect of removing S was not experimentally observed below 70 ° C. The flow velocity of such gas is 0.03
The reason for defining m / min to 30 m / min is as follows. That is, when the flow velocity is less than 0.03 m / min, H ₂ S or SOx generated by the reaction between S and H ₂ O is generated.
This is because gas bodies such as cannot escape together with the gas from the pores of the slag particles. Even if the flow velocity exceeds 30 m / min and the flow velocity is increased, the effect does not increase, which is disadvantageous in terms of equipment and cost. The reason is that

The particle size of the slag is set to 25 mm or less because
If it is larger than 25 mm, desulfurization inside the slag is difficult to proceed,
Also, it is difficult to handle in operation.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The blast furnace slowly cooled slag according to the present invention has a reducing S (S ⁰ + S ²⁻ ) concentration of 0.1 wt% or less and a total S concentration of 0.5 wt% or less. Characterize. Blast furnace slag is roughly classified into granulated slag and slowly cooled slag. In the present invention, the object is slow-cooled slag. The reason for this is that, as a result of various experiments, it was found that the water granulated slag is vitrified and is therefore difficult to desulfurize.

The slow-cooling blast furnace slag according to the present invention is based on slag that has been discharged and cooled and solidified in a slag field or the like as usual. Ordinary blast furnace slowly cooled slag has reducing S
(S ⁰ + S ²⁻ ) is contained in an amount of about 0.3 wt% and total S is contained in an amount of about 1 wt%. The low sulfur concentration blast furnace slowly cooled slag according to the present invention is obtained by desulfurizing this slag. When this slag is used as a raw material for glass fiber, reducing S (S ⁰ +
The reason for setting the concentration of S ²⁻ ) to 0.1 wt% or less is that the problem of yarn breakage does not occur even if the maximum amount of blast furnace slowly cooled slag is used as a substitute for the wax stone clay which is a glass fiber raw material. Preferably, slag having an S ⁰ + S ²⁻ concentration of 0.05 wt% or less is used as the glass fiber raw material.

S ⁰ + S ^2- may be contained not only in the blast furnace slowly cooled slag but also in other raw materials.
^A lower concentration of ⁰ + S ^{2 −} is preferable because it allows a wider range of selection of other raw materials. The maximum compounding ratio of the blast furnace slowly cooled slag in the glass fiber raw material is determined by the chemical composition defined by the glass fiber and is about 40 wt%. The reason for setting the total S concentration to 0.5 wt% or less is that due to the H ₂ S and SOx generated from the blast furnace slowly cooled slag even when the maximum amount of the blast furnace slowly cooled slag is replaced as a substitute for silica stone which is a raw material for autoclave-processed building materials. This is because corrosion inside the autoclave does not occur. The maximum blending ratio of the blast furnace slowly cooled slag in the autoclaved building material is determined by the composition of minerals such as zonotolite and tobermorite, and is about 50 wt% in the case of tobermorite.

According to the method for producing a low-sulfur-concentration blast furnace slowly cooled slag according to the present invention, the blast furnace slowly cooled slag is brought into contact with a gas containing steam at a temperature of 70 ° C. or higher to obtain S.
⁰ + S ^2- concentration of 0.1 wt% or less, and total S concentration of 0.
It can be 5 wt% or less. The reason why the temperature is 70 ° C. or higher is that there is almost no desulfurization effect at temperatures lower than 70 ° C.

The reason why the gas containing steam is used is that the coexistence of steam causes the sulfur content in the slag to change to H ₂
This is because they are removed as S and SOx. In Figure 1, all S
Shows the relationship between the heat treatment temperature and the total S when the blast furnace slowly cooled slag of 1.0 wt% was treated in an air atmosphere at atmospheric pressure for 1 hour. If water vapor does not coexist, as shown in FIG. 1, desulfurization does not occur unless the atmosphere has a temperature higher than 1000 ° C.
The presence of water vapor enables desulfurization at low temperatures. In the present invention, the type of gas used is not limited. In addition to gases such as air and nitrogen, boiler exhaust gas, heating furnace exhaust gas and the like can be used. Further, although the total pressure of the atmosphere is not limited, desulfurization can be performed in a shorter time in a higher pressure atmosphere.

[0020]

Next, embodiments of the present invention will be described. Table 1 shows the chemical composition of the slowly cooled blast furnace slag used in the experiment of this example. The blast furnace slowly cooled slag used in the experiment contained 0.3% S ⁰ + S ^{2 −} .
1 wt% and 1.03 wt% of total S are included. The desulfurization treatment was performed by exposing this blast furnace slowly cooled slag to the atmosphere shown in Table 2. The results are shown in Table 2. As shown in Comparative Example 1-1, when the temperature is lower than 70 ° C., almost no desulfurization is performed. In addition, as shown in Comparative Examples 1-2 and 1-3, 70
Even if the temperature is above ℃, it will not be sufficiently desulfurized in the absence of water vapor. Furthermore, as shown in Comparative Example 1-4, when the amount of water vapor is too large, it is difficult to desulfurize, and as shown in Comparative Example 1-5, it is difficult to desulfurize even when the flow rate is low. As shown in Comparative Example 1-6, even if the particle size is larger than 25 mm, desulfurization is difficult. On the other hand, as shown in Examples 1-1 to 1-8, the grain size is 25
mm 0, a flow rate of 0.03 m / min or more, a temperature of 70 ° C. or more, and an atmosphere in which water vapor coexists at 15 to 50% by volume, the S ⁰ + S ²⁻ concentration is 0.1 wt% or less, and the total S concentration is 0%. It can be 0.5 wt% or less.

Table 3 shows that various kinds of S ⁰ + S ²⁻ concentration and total S concentration blast furnace slowly cooled slag were used as glass fiber raw materials and autoclave-processed building material raw materials to generate bubbles during glass raw material melting, glass fiber yarns. It shows the result of investigating breakage and corrosiveness inside the autoclave. Example 2-
As shown in 1 and 2-2, the S ⁰ + S ^2- concentration is 0.1 w
By using slag of t% or less and total S of 0.5 wt% or less as a raw material, even if the compounding ratio of the blast furnace slowly cooled slag in the glass fiber raw material is 40 wt%, which is the maximum, Generation and yarn breakage do not occur, and corrosion inside the autoclave does not occur even if the blending ratio of the blast furnace slowly cooled slag in the autoclaved building material is 50 wt%.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

EFFECT OF THE INVENTION S which is the form of sulfur in the slow-cooled blast furnace slag
⁰ + S ^2- concentration of 0.1 wt% or less, and total S concentration of 0.
By making it 5 wt% or less, when manufacturing glass fiber,
Without generating bubbles and thread breakage during melting,
In addition, during autoclave-processed building material production, corrosion inside the autoclave does not occur. Therefore, the blast furnace slowly cooled slag can be used in large amounts as a glass fiber raw material and as an autoclave-treated building material raw material.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between heat treatment temperature and total S.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroyuki Tobo, 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Inside Technical Research Institute, Kawasaki Steel Co., Ltd. (72) Masato Kumagai 1, Kawasaki-cho, Chuo-ku, Chiba (72) Inventor Norihiro Ueda 2-4-1 Shiba Park, Minato-ku, Tokyo Inside Kawatetsu Mining Co., Ltd. (72) Inventor Yoshio Suzuki, 1 Niihamacho, Chuo-ku, Chiba City Stock Research Institute

Claims (2)

[Claims] 1. Reducing S ≦ 0.1 wt%, and total S ≦
Low-sulfur concentration blast furnace slowly cooled slag characterized by being 0.5 wt%. 2. A slowly cooling blast furnace slag having a particle size adjusted to 25 mm or less is brought into contact with a gas containing 15 to 50% by volume of steam at 70 ° C. or higher at a flow rate of 0.03 m / min to 30 m / min. A method for producing a slowly cooled blast furnace slag having a low sulfur concentration.