JPS6037066B2 - Manufacturing method of densified granulated slag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing densified granulated slag suitable for use in concrete mortar, etc.

With the development of the steel industry, the amount of molten blast furnace slag produced as a by-product from blast furnaces has also increased, but while some of it is being used effectively, the reality is that most of it cannot be disposed of. Conventionally, two methods have been used to treat such molten blast furnace slag.

One method is to discharge molten blast furnace slag onto a vast site, allow it to cool naturally, then dig it up with a bulldozer or the like, crush it into appropriate sizes, and use it as ballast. Another method is to inject water into molten blast furnace slag and rapidly crush it to produce so-called granulated slag with a diameter of 5 or less, which is used as a raw material for blast furnace cement. By the way, it has been a long time since it has been pointed out that there is a shortage of natural sand for concrete and mortar used in the fields of architecture and civil engineering. Therefore, research into artificial sand as an alternative to natural sand is active, and the application of blast furnace slag in this field is also being considered. However, the above-mentioned method of manufacturing balas mainly yields large pieces, so in order to make them into tsumugi-kotsu villages, they must be crushed, but balas are very strong and therefore suitable for tsumugi-kotsu-mura. It is extremely difficult and uneconomical to crush to a particle size (less than 5 sides). In addition, since most of the granulated slag has a particle size of 5 or less in diameter, it is suitable for use as fine aggregate, but since it is soft and coarsely glassy, it is There are problems with strength, specific gravity, water absorption rate, etc., and it is unsuitable for use as a material. As a result of conducting research from the perspective of using blast furnace slag primarily as pongee aggregate, the present inventor found that
The inventors have determined that the most appropriate method is to densify granulated slag, and have arrived at the present invention.

That is, the present invention is a method for producing granulated granulated slag, which is characterized by adding an iron oxide-containing substance to molten blast furnace slag and then converting it into granulated slag at room temperature.

Suitable materials containing iron oxide include converter slag and iron ore.

When these substances are added alone or in a mixture to molten blast furnace slag, sufficiently dissolved, and then converted into granulated slag using the usual method, extremely heavy fibers with high surface dry apparent specific gravity and low water absorption are produced. A densified granulated slag is obtained. At this time, the amount of the iron oxide-containing substance added may be about 2.5% or less in terms of iron oxide amount (in terms of Fe○, hereinafter the same) as a result of various experiments. The particle size of the iron oxide-containing substance is suitably less than 2 ribs, and if it is larger than that, undissolved residue will occur, which is not preferable. FIG. 1 is a graph showing the surface dry apparent specific gravity of a product when converter slag containing approximately 50% of 2.5 ribs or more is added. In the graph, a solid line with arrows at both ends is shown from around 60 minutes to around 80 minutes, which indicates the timing of charging the converter slag. The meaning of this solid line is the same in other figures. The addition rate of converter slag is 15
1k9/min (0.9% iron oxide amount). What is clear from this graph is that the amount of slag increases over time, and the surface dry apparent specific gravity of granulated slag tends to decrease as shown by the dot-dash line. Even if slag is added, in this experiment, the surface dry apparent specific gravity of the granulated slag is only about 224 at most. The water absorption rate is shown in parentheses along the curve, and is 2.8% at its best. On the other hand, FIG. 2 is a graph showing the surface dry apparent specific gravity of the product when the same converter slag with a particle size of 1.2 or less is added.

As is clear from this graph, the rise of the curve due to the addition of converter slag was steep, the maximum surface dry light specific gravity reached nearly 2.6, and the water absorption rate also decreased to a maximum of 0.7. In the above two experiments, the particle size of converter slag was 50%
Relatively large ones, such as those included, indicate that there is no significant effect.

This tendency was the same for other iron oxide-containing substances.
Figure 3 shows iron ore powder at 91k9/min (iron oxide content: 2
．． This is an experimental example in which iron ore powder was added to molten blast furnace slag at a ratio of 5%), and in this case as well, the surface dry apparent specific gravity of granulated slag rose sharply due to the addition of iron ore powder, and the water absorption rate was also improved. It has also been found that good results cannot be obtained unless the moisture content of the iron oxide-containing material is about 1%.

For example, when we conducted an experiment in which converter slag with an attached moisture content of 4% was added to the molten blast furnace slag at 2%, the molten blast furnace slag bubbled in the gutter and the level rose rapidly, making it difficult to continue work. . The appropriate location for adding the iron oxide-containing substance is a sloping path branching off from the runner, as close to the branching point as possible. Example 1 In the vicinity of the junction of the sloping path branching from the runner attached to the blast furnace, Fe2033.4%, Ca037.4%, S
i0210.7%, Mg08.8%, Mn2036.1
%, peak 2031.8%, 1g, loss+1.9 dry converter slag with a particle size of 1.2 ribs or less at 115k9/
It was added at a rate of 100 min.

The flow rate of blast furnace slag at the time of addition was about $/min, and from this the amount of iron oxide in the additive was equivalent to 0.9%.
When such molten blast furnace slag was converted into granulated slag using a conventional method, a fine granulated slag with an average surface dry screening specific gravity of 2.59, a water absorption rate of 0.7%, and a glass content of 99.5% was obtained. Ta.
Example 2 Fe20393.5%, Si025.19%, Ca00
．． Dry specularite powder having a composition of 45% Mg, 00.29% Mg, 2030.25% AI and a particle size of 0.6 or less was added to the molten blast furnace slag at the same position as in Example 1 at an addition rate of 91k9/min. did.

The amount of blast furnace slag at the time of addition was 2.5 tons/minute, and from this the amount of iron oxide in the additive was equivalent to 2.5% on average. When such molten blast furnace slag was made into granulated slag using a conventional method, the surface dry apparent specific gravity was 2.
70, a fine granulated slag with a water absorption rate of 1.0% and a glass content of 99.5% was obtained. The granulated slag according to Examples 1 and 2 above can be used as fine aggregate for concrete mortar, and according to the test results, it can be used for practical purposes without adversely affecting the water-cement ratio, fluidity, strength, etc. As part of the effective use of blast furnace slag, its usefulness is extremely high from the standpoint of resource conservation.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship when converter slag with a grain size of 2.5 grains or more is added to molten blast furnace slag. Figure 2 is a graph when converter slag with a grain size of 1.2 Yanagi or less is added. FIG. 3 shows graphs when iron ore powder is added. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. Densified water characterized by adding an iron oxide-containing substance to molten blast furnace slag in an amount of 2.5% or less in terms of iron oxide content, and then converting this into granulated slag by a conventional method. Manufacturing method of crushed slag. 2. The method for producing densified granulated slag according to claim 1, wherein the iron oxide-containing substance is converter slag. 3. The method for producing densified granulated slag according to claim 1, wherein the iron oxide-containing substance is iron ore. 4. The method for producing densified granulated slag according to any one of claims 1 to 3, wherein the particle size of the iron oxide-containing substance is 2 mm or less.