KR920005400B1 - Preparation method of fireproofing adiabatic material - Google Patents

Abstract

A refractory thermal insulator comprises blast furnace discharged water granulation slag of 57-60 wt.% having the particle size of 0.5-1.0 mm, blast furnace sludge of 30-35 wt.%, and bentonite of 3-5 wt.%. The mixture contains an organic binder which consists of sodium carboxylmethyl cellulose and the water with the ratio 1:1. The amount of binder and water is 10-20 wt.% against thermal insulating mixture. Refractory thermal insulator is manufactured by firing the mixture at 1,100-1,150 deg.C.

Description

Manufacturing method of fireproof insulation

1 is a graph showing the change in volume specific gravity according to the particle size of the slag.

2 is a graph showing the change in volume specific gravity depending on the firing temperature and the additive.

3 is a graph showing changes in compressive strength according to firing temperature and additives.

4 is a graph showing the change in volume specific gravity according to the amount of the inorganic binder added.

5 is a graph showing the change in compressive strength according to the amount of the inorganic binder added.

The present invention relates to a method of manufacturing a fireproof insulation material, and more particularly, to the manufacture of a fireproof insulation material which can improve the thermal efficiency of a furnace body or a building by utilizing blast furnace crushing slag and blast furnace sludge as by-products in the steel manufacturing process as main components. will be. Conventional methods for producing fireproof insulation include heating a natural raw material to produce a swelling phenomenon caused by decomposition of low melting point materials such as crystalline water, and adding a flammable or sublimable material to the raw material to be fired. Method and other methods of adding a foaming material are known, and diatomaceous earth, pearlite, obsidian, refractory clay, vermiculite and the like are used according to the characteristics of the raw materials. Currently, blast furnace slag and blast furnace sludge are being used in the iron and steel industry together with pig iron production. However, since blast furnace slag has latent hydraulic properties, effective methods of coating materials, cement, concrete coarse aggregate, fine aggregate, and fertilizer are known in the art, and blast furnace slag is mixed with cement or water glass at 200 ° C. or lower. It is known to dry or to dry the water of the crushed slag and to apply 10-15% limestone to make bricks.

And the use of blast furnace slag in the production of refractory insulating bricks is known from Korean Patent Publication No. 88-2431, in this case, the blast furnace slag with a particle diameter of 1-2mm, as the main component, the organic bonding material carboxymethyl cellulose Bentonite and refractory clay are added as an inorganic binder and fired at a temperature of 1150-1300 ° C. However, unlike blast furnace slag, blast furnace sludge has been abundantly produced in the blast furnace process, but despite the fact that it contains a considerable amount of useful components (carbon: 30-40%) due to the inclusion of harmful components, it has been discarded.

Accordingly, an object of the present invention is to produce a refractory insulation and thermal insulation material that can be used to increase the thermal efficiency of various furnaces or buildings by mixing blast furnace slag and blast furnace sludge as by-products in the blast furnace process at a constant ratio. Hereinafter, the present invention will be described in detail.

The present invention relates to carboxy, which is an organic binder, in a mixture containing a conventional blast furnace chain slag having a particle diameter of 0.5-1.0 mm: 50-60% by weight, blast furnace sludge: 30-35% by weight, and bentonite: 3-5% by weight. Methyl cellulose sodium and water are uniformly mixed in a 50: 50 weight ratio by adding 10-20% by weight to the weight of the mixture and then molded and fired at a temperature of 1100-1150 ℃ to more than this It will be described in detail as follows. The blast furnace chain slag and the blast furnace sludge are usually mixed at a constant ratio, and an inorganic binder is preferably mixed with 3-5% of bentonite, and then carboxymethyl cellulose sodium, which is an organic binder, is used to improve low temperature strength and molding. Water is mixed in a 50: 50 weight ratio and finely ground to add 10-12 wt% of the mixture to the mixture weight. In addition, as shown in FIG. 1, since the volume specific gravity varies greatly depending on the particle size of the slag, the slag particle size is uniformly mixed by adding the binder with the blast furnace sludge using a sample having a particle size of 0.5 mm or more and 1 mm or less. It is then put into a mold and press-molded, and the molded body is dried for 1 hour and 30 minutes at a constant temperature of 110 ℃ and then fired by maintaining for 2 hours at a temperature of 1100-1150 ℃ in an electric furnace, etc. Insulating material is prepared, the temperature rise to the firing temperature is preferably raised in order sequentially for 30 minutes from room temperature to 400 ℃, 1 hour from 400 ℃ to 800 ℃, and 1 hour 30 minutes from 800 ℃ to the firing temperature.

When the blast furnace slag is calcined at high temperature, it has thermal volume expansion characteristics according to the crystallization of alumina in the components, and in the case of blast furnace sludge, it is localized due to the exothermic reaction heat due to the oxidation reaction of a large amount of carbon in an oxidizing atmosphere when added at a constant ratio In addition to the improvement of the plasticity characteristics and the development of the pore structure in the sample due to the diffusion of the combustion gas and the volatilization of the low melting point component, it is possible to form a refractory insulating structure. Hereinafter, the present invention will be described in detail through examples.

EXAMPLE

The structural plasticity characteristics and compressive strengths of the mixed ratios of the blast furnace slag and the sludge and the blast furnace slag and the coke in the same ratio as shown in Table 1 were measured and the results are shown in Table 1 below.

TABLE 1

As shown in Table 1, the structural plasticity characteristics and compressive strengths of the blast furnace slag and the blast furnace sludge were significantly different, which is due to the volatilization of some low melting components of the blast furnace sludge or oxidation of carbon. It is estimated to be significantly affected by the visual observation, and the visual observation shows that only the mixing ratio of 2: 1 shows uniform pore distribution.

And the addition of coke instead of sludge showed a very dense reaction characteristics, it can be seen that the volumetric ratio also shows a significantly higher result than the addition of sludge.

Among the mixtures shown in Table 1 above, blast furnace slag: sludge ratio of 2: 1 is added to the mixture of blast furnace slag and sludge with inorganic binders such as bentonite or refractory clay in a proportion as shown in Table 2 below, and then mixed with blast furnace slag. , 12% by weight of carboxy methyl cellulose sodium as an organic binder was added to the total weight of the sludge and the inorganic binder, and then fired at 1150 ℃ to prepare a refractory heat insulating material, and the physical properties are shown in Table 2 below.

TABLE 2

As shown in Table 2, the invention material has a softening temperature of 1310 ℃ or more, as can be seen in the following 3 showing the thermal expansion characteristics of the invention material, it causes a slight volume expansion in the temperature region below 1310 ℃. It can be seen that the reheat shrinkage problem generated in the conventional heat insulator is compensated.

TABLE 3

Example 2

For the invention material, comparative material B and the conventional material shown in Table 2 of Example 1, the volume specific gravity and the compressive strength according to the firing temperature were measured, and the results are shown in FIGS. 2 and 3. As shown in FIG. 2 and FIG. 3, only the present invention exhibited a specific gravity of less than 1.1 at a firing temperature of 1150 ° C., and the present invention also exhibited more than 50 when the firing temperature was above 1150 ° C. even in compressive strength. Able to know.

In the case where the carboxymethyl cellulose sodium, which is an organic binder added for the purpose of maintaining the low temperature strength, was not added, all of them exhibited a specific gravity of 1.1 or more in the experimental temperature range. It is assumed that organic binders are decomposed in the temperature range of 300 ℃ or higher, so that the coking force disappears, but the pore structure is developed during the carbonization process.

Example 3

For the inventive material and the comparative material B shown in Table 2 of Example 1, the volume specific gravity and the compressive strength according to the addition amount of bentonite and refractory clay were measured, and the results are shown in FIGS. 4 and 5. As shown in FIG. 4 and FIG. 5, as the addition amount of bentonite increases, the overall weight ratio is increased, and the volume specific gravity of less than 1.1 is obtained only when the bentonite addition range is 3-5%. In general, the characteristics of refractory bricks are defined in terms of low specific gravity, high thermal conductivity, high compressive strength, and less than 2% of reheat shrinkage.

In order to form and fire the mixture of blast furnace slag and blast furnace sludge of the present invention, it was prepared by adding bentonite as a binder and subjected to a characteristic test. As a result, it was evaluated as a C-1 grade fireproof insulation brick prescribed in KSL 3301. It has the same characteristics as refractory insulation bricks or blast furnace slag bricks, which can extend the use particle size of raw materials, lower the firing temperature, and increase the added value by utilizing the blast furnace slag that is a by-product of the steel industry and the blast furnace sludge that is entirely discarded. There is.

As described above, the present invention uses the high temperature expansion characteristics of the blast furnace slag, the oxidation reaction of the carbon contained in the sludge and the volatilization characteristics of the low melting point material, so that the refractory insulation material of the present invention is shown in Table 2. As shown in Table 3, it has a softening temperature of more than 1310 ℃, and as shown in Table 3, there is a slight volume expansion, and the problem of reheating shrinkage caused by the conventional refractory insulation material (clay or silicon soil) is compensated. The pretreatment can also be omitted, which simplifies the manufacturing process and, as a raw material is produced by waste in the iron and steel industry, it brings cost saving and waste utilization effects.

Claims (1)

Ordinary blast furnace slag having a particle diameter of 0.5-1.0 mm; 57-60% by weight, blast furnace sludge: 30-35% by weight, and bentonite; The mixture containing 3-5% by weight of carboxymethyl cellulose sodium as an organic binder and water were uniformly mixed in a 50:50 weight ratio, and then molded by adding 10-20% by weight of the mixture to 1100-1150 ° C. Process for producing a refractory insulating material, characterized in that the firing at a temperature.

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