JPS62113738A - Manufacture of hard water-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 the Invention The present invention relates to a method for producing granulated slag. In more detail, a large amount of molten blast furnace slag (
The present invention relates to a method for inexpensively and stably producing granulated slag used as fine aggregate for concrete, particularly hard and dense granulated slag having the same quality as natural sand, from molten slag (hereinafter referred to as molten slag).

Conventional technology In recent years, river sand extraction regulations have been implemented from the perspective of environmental protection, resulting in a shortage of natural sand supply, and the deterioration of its quality has been seen as a problem.As a result, the recycling and effective use of blast furnace slag has been rapidly progressing. Active research is being conducted in various fields to use blast furnace slag as a substitute for natural sand.

Generally, granulated slag as a substitute for natural sand is produced by allowing an appropriate amount of molten slag to flow down into high-pressure jet water, and the following methods have been proposed as such methods.

(A) As shown in Figures 2 and 3, the molten slag (2) is ejected from the compressed air injection source (3) installed behind the molten slab (2) falling from the molten slab gutter (1).
After injecting compressed air (4) to roughly crush and scatter the molten slag, pressurized water is injected onto the scattered slag from a downwardly inclined pressure water nozzle (6) to form coarse granulated slag. Manufacturing method (see Special Publication No. 60-6300)
or (B) A method of producing granulated slag of any quality by adjusting the flow rate of pressurized water jetted from the nozzle hole of a blowing box within a certain range shown in FIG. 4 (1) and (If). (Refer to Japanese Patent Application Laid-open No. 121140/1983).

Problems to be Solved by the Invention However, even with the above-mentioned method, it is still difficult to achieve hard and dense granulation that satisfies the unit volume mass and coarse particle ratio, which are important criteria for quality evaluation in the continuous production of granulated slag. It has not been possible to produce it stably, industrially and economically.

Steps to Solve the 4 Problems As a result of repeated studies in view of the above problems, the inventors have determined a specific combination of water It (water/slag ratio) and water temperature of the pressurized water in the blowing process. It was discovered that granulated slag having any desired quality can be obtained by adjusting it within the range, and the present invention has been completed.

That is, the present invention provides a method for producing granulated slag in which molten slag produced by-product during blast furnace operation is dropped from a molten slag gutter, and pressure water is injected onto the slag to finely crush and granulate it. Hard water characterized in that the temperature and water/slag ratio of the pressurized water used are in the area surrounded by curves A, B, C1, straight line D1, straight line E1, straight line F and straight line G shown in the attached FIG. A method for producing crushed slag is provided.

The curve A-C and the straight line D-G are expressed by the following formula on a coordinate axis with the water/slag ratio as the horizontal axis (X axis) and the temperature of the pressure water as the vertical axis (Y axis).

Curve A: Y=-68.7+64.0&nX Curve B: Y=
-109,0+63. H! nX curve C: Y=-240,
2+ l l 9.3 (!n When the temperature rises, a large amount of foamed soft granulated slag is generated.
On the other hand, when the blowing water temperature decreases in winter, the particles become finer and become out of specification, and the flow rate of molten slag discharged from the blast furnace fluctuates over time, and the quality of granulated water changes accordingly. This was done based on the knowledge of the phenomenon of

That is, the normally used hard granulated slag manufacturing equipment is shown in FIG.

The molten slag (2) falling from the molten slag gutter (1) is
The high temperature region is rapidly cooled by compressed air (4) injected from a compressed air injection source (wind box) (3) provided behind it, and precooling and dispersion is performed. Then, pressurized water (7) is injected onto the coarsely crushed scattered slag (5) from a pressure water nozzle (blown box) (6) to form coarse granulated water slag (8).
This is transferred to the granulated slag gutter (10) using the conveyed water (9).
The upper part is drained into a water tank to form hard granulated slag.

The hard granulated slag produced in this manner is lightly crushed using an auto fine crusher or a rod mill to improve the particle shape and particle size and produce a fine slag aggregate product. The crusher removes the angularity of the hard granulated slag particles to improve the particle shape and adjust the overall particle size to a predetermined range.

When the blown granulated slag is crushed, the coarse particle ratio decreases and the unit volume mass increases. That is, in order to keep the quality of the slag fine aggregate product after crushing within a predetermined range, it is essential that the untreated slag before crushing falls within a corresponding certain quality range.

As a result of examining various conditions from this point of view, we found that the coarse grain ratio of the raw granulated slag after blowing and before crushing is 3.0 or more, and the unit volume quality is stable within the range of 9/Q from 11.3 to 1.5. It has been found that slag is most suitable for producing fine aggregate products of high quality.

Although it is possible to adjust the quality of granulated slag by changing the amount of crushing processed by the crusher, there is a limit, and from the standpoint of equipment productivity, it is necessary to reduce the amount of processing and the adjustment range of the machine. It is desirable to produce each type of product separately, and it is not desirable to adjust the quality of granulated slag products by changing the amount of crushing.

Conventionally, raw granulated slag with quality within this range has been targeted. Although granulated slag has been manufactured by the above-mentioned known methods, these methods have large quality fluctuations and often deviate from a predetermined range, resulting in many non-standard products. As a result of various studies to find out the cause, the present inventors found that the amount of pressure water (water/slag ratio) and water temperature during blowing have the greatest influence, and that the following relationship holds true. Ta.

That is, immediately after discharging molten slag that had been brought into a molten state (1500° C.) in an electric furnace from the furnace, various tests were conducted using the temperature and flow rate (water/slag ratio) of the injected pressurized water as control factors. Tests were conducted at a water temperature of 4 to 80°C and a water/slag ratio of 5 to 15 to determine the relationship between coarse particle ratio and unit volume mass. The results are shown in Figure 1. As is clear from Figure 1, curve C: Y=-240,2+119.312nX
A coarse grain ratio of 3.0 or more is satisfied in the upper region. On the other hand, the ``P'' volume quality m is curve A: Y=-68, 2+64.
1,3 ktt/ρ or more below 0&nX, curve B:
Y=-109,0+63.1NnX Upwards 1,5
kg/Q or less can be obtained. Also, the water/slag ratio to the right of straight line D:X=5 is preferable for safety, while straight line E:
An economical water/slag ratio is obtained to the left of X=15. In other words, if the water/slag ratio is less than 5, there is a risk of steam explosion due to fluctuations in the slag flow rate, and if it is more than 15, it is necessary to prepare a large amount of blowing water for circulation and reuse in the storage tank, which is not practical. Not the point. Therefore, the water/slag ratio is 5
As mentioned above, a range of less than 15 is desirable. Also, the water temperature is 10~
The temperature should be in the 90°C range. If the water temperature is 90° C. or higher, the amount of water vaporized increases and the pump efficiency decreases, which is a problem.

If the temperature is below 10°C, it will be easily affected by the outside air, and especially in winter, there is a risk that the water pipes may freeze and disrupt the operation of the equipment. Therefore, IO≦Y≦90.

More preferably, the water temperature is 40 to 60°C, and the water/slag ratio is in the range of 7 or more and IO or less (the meshed area in Figure 1), and the granulated slag is industrially stable and has the desired quality. can be manufactured efficiently and economically. In other words, it is economically undesirable to set the temperature of the blowing water to less than 40°C due to annual atmospheric temperature changes, and if it exceeds 60°C, there is a possibility that curve A will be exceeded due to the rise in temperature due to the sensible heat of the slag. . Therefore, the water temperature is preferably in the range of 40 to 60°C. In addition, in order to uniformly rapidly cool the molten slag by pressurized water and stabilize the particle size distribution, compressed air may be injected immediately before injecting the pressure water so that the cross-sectional shape of the molten slag flowing down from the molten slag gutter becomes plate-like. More preferred.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Granulated slag was manufactured using the blowing apparatus shown in FIG.

In the figure, the molten slag falling from the molten slag 1a (1) (
2) (For example, temperature 1470-1480°C, flow ff12.
6 tons, 7 minutes), air fi
Inject 200 u3/min of compressed air (slag: air (volume ratio) = 1:2 QO) I, After roughly crushing the molten slag and scattering it into a plate or thin layer, pressurized water nozzle (6
) was injected with pressurized water at a flow rate of 7 tons (water/slag ratio = 8) at a temperature of 45° C. to crush and granulate the slag to obtain hard granulated slag. This hard granulated slag was lightly crushed using an auto fine crusher to obtain a slag fine aggregate product. The physical properties of the obtained granulated slag are shown below.

Absolute dry specific gravity 2.67 2.72 Water absorption rate (%
) 0.36 0.30 unit volume quality ff1
1.37 1.51 (kg/σ) Coarse particle ratio 3,43 2.53 Example 2 The molten slag that flowed out from the blast furnace through the molten slag gutter was picked up by a pot truck and transported to the fracking equipment. This molten slag (1380-1400°C) is discharged at a flow rate of 2 tons/min while tilting the molten slag pot, and the molten slag slag is heated at 40°C and flow rate is 14 tons/min (water/slag ratio =
7) Pressure water was injected to crush and granulate the slag to obtain hard granulated slag.

This granulated slag was lightly crushed using a rod mill to obtain a slag fine aggregate product. The physical properties of the obtained granulated slag are shown below.

, absolute dry specific gravity 2.60 2.77 water absorption rate (
%) 0.5 summer 0.39 unit volume mass
1.35 1.61 (&9/(2) Coarse particle ratio 3.45 2.59 The chemical composition of the granulated water obtained in the above Example! and 2 is J
It fully satisfies IS standards and also satisfies JIS standards as a slag fine bone product.

Effects of the Invention According to the present invention, physical properties equivalent to natural sand (absolute dry specific gravity, unit volume mass, water absorption rate, and coarse particle ratio ), it is possible to stably and inexpensively produce high-quality hard granulated slag that satisfies the JTSM1 rating.

[Brief explanation of drawings]

Figure 1 shows the relationship between the temperature and flow rate (water/slag ratio) of pressurized water to obtain a coarse grain ratio of 3.0 or more before crushing and a unit volume mass of 1.3 to 1.5 kg/(l). Graphs, Figures 2 and 3 are schematic diagrams showing the conventional granulated slag manufacturing method, Figure 4 is a graph showing the adjustment range of pressure water in the conventional granulated slag manufacturing method, and Figure 5 is a diagram showing the method of the present invention. 1 is a schematic diagram showing the equipment used for this purpose. The main symbols in the diagram are as follows: !: Molten slag gutter, 2: Molten slag, 7: Pressure water, 8:
Granulated slag.

Claims (3)

[Claims] (1) In a granulated slag production method in which molten slag, which is produced as a by-product during blast furnace operation, falls from a molten slag gutter and is injected with pressurized water to finely crush and granulate the slag, the pressure used for blowing is A hard material characterized in that the water temperature and water/slag ratio are in the area enclosed by curves A, B and C, as well as straight lines D, E, F and G shown in the attached FIG. Method for producing granulated slag. (2) Pressure water temperature is 40-60℃, water/slag ratio is 7
The method according to item (1) above, wherein the number is 10 or less. (3) Item (1) or (2) above, in which compressed air is injected immediately before pressurized water injection to treat the pre-cooled and dispersed molten slag.
Section method.