JPH01252559A - Modification of blast furnace granulated 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] This invention relates to a method for modifying granulated blast furnace slag into slag having excellent reactivity and a high specific surface area by treating it with an alkaline solution. It is something.

[Prior art] In order to use granulated blast furnace slag produced as a by-product in steel plants, for example, as building materials, water treatment materials, water absorbing materials, fillers, etc., it is necessary to modify its surface properties and increase its specific surface area. It is necessary to increase it.

As a reforming method for such granulated blast furnace slag,
No. 7-703 discloses a method consisting of the following: finely powdered granulated blast furnace slag is added to an alkaline solution at a ratio of 10 to 40 g per 100 mff1 of the alkaline solution and stirred for a predetermined period of time. Hydration reaction treatment, then
The slag subjected to the hydration reaction is separated in a mill, and the slag separated in a furnace is washed with water and then dried at a temperature of 110° C. (hereinafter referred to as prior art).

[Problems to be Solved by the Invention] According to the above-mentioned prior art, when the hydration reaction time is 3 hours, the specific surface area of granulated blast furnace slag is 1 m2/g or less when not treated (however, in the Blaine method) compared to 63-6
It can be increased to 9M/kg (however, B, E, T, method).

However, with the above specific surface area, when used as a raw material for building materials, water treatment materials, water absorbing materials, plastic fillers, etc., the water absorption of the product and the impact resistance when used as a plastic filler are etc. cannot be said to be sufficient,
There is a need to develop a method for modifying granulated blast furnace slag to obtain higher non-surface area in a short time.

Therefore, the object of this invention is to produce granulated blast furnace slag.

The object of the present invention is to provide a method for modifying slag into slag having excellent reactivity and a high specific surface area, which is suitable as a raw material for building materials, water treatment materials, water absorbing materials, fillers, etc.

[Means for Solving the Problems] The present invention includes adding 5 to 10 g of granulated blast furnace slag powder to an alkaline solution of a predetermined concentration per 100 mfi of the alkaline solution.
The granulated blast furnace slag powder subjected to the hydration reaction is washed with water to remove residual alkali, and then heated and dried at a predetermined temperature. Modifying the granulated blast furnace slag powder so that its specific surface area is 9 Onζ/g or more, preferably, the heating temperature is 450° C. or more, 850° C.
C. or less, the granulated blast furnace slag powder is modified so that its specific surface area becomes 120 i/g or more.

In the present invention, it is preferable that the granulated blast furnace slag before reforming be made into fine powder having a maximum particle size of substantially 10 μm or less. If the maximum particle size is substantially more than 10 μm, it is impossible to modify the slag powder into a slag powder having a specific surface area of 90 m 2 /g or more.

In order to turn the granulated blast furnace slag into a fine powder as described above, the input lag must be milled in a ball mill etc. so that its specific surface area is, for example, about 4.
It is necessary to crush the slag until it becomes 0OOcJ/g, and then classify the slag crushed as described above using an air classifier or the like.

If the slag is pulverized only by a pulverizer such as a ball mill, a large amount of time and energy will be consumed, and the surface activity of the pulverized slag will be reduced.

The addition ratio of granulated blast furnace slag to the alkaline solution needs to be 5 to 10 g per 100 rn Q of the alkaline solution. As in the prior art, when the addition ratio to 100 mQ of alkaline solution exceeds 10 g,
The desired reforming effect cannot be obtained. -1 side, alkaline solution 1
If the addition ratio to 00 mI2 is less than 5 g, there will be a problem that the economical efficiency will be lowered.

As the alkaline solution, it is desirable to use a caustic soda solution with a concentration of 1N or higher. If the concentration is less than 1N, the modification effect will be low.

The hydration reaction temperature of fine slag powder in an alkaline solution is
It is desirable that the temperature is 90°C or higher. Hydration reaction temperature is 90
Below ℃, the modification effect is low.

What is the heating temperature of granulated blast furnace slag after hydration treatment and subsequent washing with water to remove residual alkali?

Granulated blast furnace slag powder with an average particle size (50% particle size) of 1.5μ was added to a NaOH solution at a temperature of 90°C and a concentration of 3N at a ratio of 5g per 100mQ of the solution. A hydration reaction was carried out by stirring for hours. Next, samples were prepared by separating the granulated blast furnace slag suspended in the NaOH solution and subjected to the hydration reaction treatment by furnace. The obtained sample 15.1B was subjected to differential thermal analysis by heating to 1000° C. at a rate of 10° C. for 7 minutes.

FIG. 1 is a graph showing the above-mentioned differential thermal analysis results, in which the horizontal axis shows the heating temperature, and the vertical axis shows the relative values of exotherm (su) and endotherm (-). As is clear from FIG. 1, the sample showed an endothermic peak when the heating temperature was 450°C. Due to the endothermic action at this time, the CaO produced in the above-mentioned water utilization reaction
・m5i02・nAQ20. - Bound water of hydrates such as q1120 was removed, and the specific surface area increased significantly due to pores generated when bound water was removed. On the other hand, the heating temperature is 85
When the temperature exceeded 0°C, heat generation became intense and the sample deteriorated. From this, the preferable range of the heating temperature is 45
It was found that the temperature was 0°C or higher and 850°C or lower.

[Example] Next, the present invention will be explained based on examples.

Granulated blast furnace slag having the chemical composition, vitrification rate, and basicity shown in Table 1 was ground by a ball mill, and had a specific surface area of 3,840 crJ/g.

Slag powder with an average particle size (50% particle size) of 10 μm! I
! Made by l.

Next, the slag powder obtained above was charged into an air classifier and classified with a DP50 (50% particle size) of 3 μIll, so that the non-surface area was 18,920 ad/g and the average particle size was 1. A fine slag powder of 5μI11 was prepared. The obtained slag fine powder was heated to a temperature of 90°C and 3°C.
The fine slag powder was subjected to a hydration reaction treatment by adding it to a specified NaOH solution at a ratio of 5 g per 100 mQ of the solution and stirring for 73 hours.

Next, the slag differential suspended in the NaOH solution, which has undergone the hydration reaction treatment, is separated by furnace.

The separated fine slag powder was dried by heating at a temperature of 100°C for 4 hours, and then crushed to prepare the specimen NQI of the present invention.6 Also, the separated fine slag powder was heated at a temperature of 450°C for 4 hours. The sample Nα2 of the present invention was prepared by drying it by heating for a period of time and then crushing it.

FIG. 2 is a graph showing the specific surface area of the present invention specimens &1 and &2. As is clear from FIG. 2, the specific surface area of the present invention specimen Nα1 when subjected to slight crushing is 10
2 m2/g, and the non-surface area of one present invention specimen Nn2 was 122 m2/g.

Figure 3 is an electron micrograph (5000x magnification) of the present invention specimen Nα2, and Figure 4 is a slag fine powder (with a specific surface area of 18,920 cJ/g before hydration reaction treatment) for comparison This is an electron micrograph (magnification: 5,000 times) of a specimen (hereinafter referred to as a comparative specimen).

As is clear from FIGS. 3 and 4, the specimen Nα1 of the present invention has many pores on one surface, and the voids are connected to the inside. In contrast, the comparative specimen has no pores on its surface and is dense.

[Effects of the Invention] As described above, according to the present invention, granulated blast furnace slag can be produced at a rate of 90 m2/g or more, especially 120 m2/g, in a short period of time.
It can be modified into a slab with a higher specific surface area, thereby making it suitable for building materials and water treatment materials.

Industrially useful effects are brought about, such as obtaining highly reactive slag suitable as a raw material for waterproofing materials and the like.

[Brief explanation of the drawing]

Figure 1 is a graph showing the differential thermal analysis results of the sample, Figure 2 is a graph showing the specific surface area of the specimen of the present invention, Figure 3 is an electron micrograph of the specimen of the present invention (sooo magnification), and Figure 4 is This is an electron micrograph (5000x magnification) of a comparison specimen.

Claims (1)

[Claims] 1. Granulated blast furnace slag powder is added to an alkaline solution of a predetermined concentration,
The hydrated blast furnace slag powder is added at a rate of 5 to 10 g to 100 ml of an alkaline solution and stirred, and then the hydrated granulated blast furnace slag powder is washed with water to remove residual alkali. A method for modifying granulated blast furnace slag, the method comprising: modifying the granulated blast furnace slag powder so that its specific surface area becomes 90 m^2/g or more by heating and drying the granulated blast furnace slag at a predetermined temperature. 2. Add granulated blast furnace slag powder to an alkaline solution of a predetermined concentration.
The hydrated blast furnace slag powder is added at a rate of 5 to 10 g to 100 ml of an alkaline solution and stirred, and then the hydrated granulated blast furnace slag powder is washed with water to remove residual alkali. 450℃ or higher, 850℃
A method for modifying granulated blast furnace slag, comprising modifying the granulated blast furnace slag powder so that its specific surface area becomes 120 m^2/g or more by heating and drying at the following temperature. 3. The method for reforming granulated blast furnace slag according to claim 1 or 2, wherein the particle size of the granulated blast furnace slag powder as a raw material is substantially 10 μm or less. 4. The method for reforming granulated blast furnace slag according to claim 1 or 2, wherein a caustic soda solution having a concentration of 1 normal or more is used as the alkaline solution. 5. The method for reforming granulated blast furnace slag according to claim 1 or 2, wherein the hydration reaction treatment is performed at a temperature of 90°C or higher.