KR20000032102A - Molding material using slag from an iron mill - Google Patents

Abstract

PURPOSE: A molding material using slag from an iron mill is provided, which is able to solve the problem of supply and demand of aggregate due to collect restriction of natural aggregate. CONSTITUTION: In the molding material using water granulation slag comprising aggregate and cement, the aggregate comprises: (i) 10-90 wt.% of water granulation slag; and (ii) 90-10 wt.% of at least one of sand, powdered limestone or slow cooling slag. In the molding material using water granulation slag and stainless slag comprising aggregate and cement, the aggregate comprises: (i) less than 50 wt.% of water granulation slag; and (ii) more than 50 wt.% of stainless slag.

Description

Molding material using steel mill slag

The present invention relates to compositions of secondary concrete products such as bricks and blocks, and more particularly, to molding materials using handmade slag and stainless slag.

In general, cement and aggregate are mixed with water to make a molding having a suitable strength, which is commonly referred to as concrete secondary product. Examples include bricks, blocks, sidewalk blocks, road boundary stones, drainage pipes, central dividers, manhole covers, and landscape stone. Aggregate which is a raw material of such a molding is mainly used natural sand or stone powder, and natural sand includes mountain sand, river sand and sea sand. However, as the regulations on protection of natural ecosystem and protection of natural environment are intensified in the future, shortage of natural sand is expected to occur, and the countermeasures are required.

On the other hand, various slag generate | occur | produce in a steel mill. For example, stainless steel slag is generated in the process of making stainless steel, as well as by-product slag and hand slag produced in the blast furnace. The blast furnace slag which is a by-product from blast furnace is used as road slag after adjusting to a certain granularity, and blast furnace slag is used as cement raw material, blast furnace cement raw material, fertilizer raw material, etc. It has never been. Stainless slag is also the same.

The present inventors have repeatedly studied the method to replace the slag produced by a large amount in the steel mill with natural sand, and as a result, it has been confirmed that it is possible to use steel mill slag as aggregate, and came up with the present invention.

The present invention proposes a molding material, which is a secondary product of concrete, by using blast-furnace slag and stainless slag as a substitute for natural aggregate.

Molding material of the present invention for achieving the above object,

(a) handmade slag: 10-90 wt%

(b) At least one or more of sand, stone powder or aggregated slag, comprising aggregate and cement mixed at 90-10% by weight.

In addition, the molding material of the present invention,

(a) Reclaimed slag: 50 wt% or less

(b) Stainless Slag: Consists of aggregates and cements mixed in at least 50% by weight.

Hereinafter, the present invention will be described in detail.

[Forming material using hand slag]

Slag is generated in the blast furnace of the steel mill, and the slag is divided into aggregate slag and wood slag according to the treatment process. Aggregate slag is a slag of molten state separated from molten iron when leaving the furnace in the steelmaking process and is gradually cooled after being crushed to a predetermined size and shipped as a mass. On the other hand, the slag is shipped in an amorphous state by quenching by spraying the pressurized water of the sewage equipment to the molten slag.

The chemical composition of the blast furnace slag (lumped slag and hand slag) is shown in Table 1.

Chemical composition (% by weight) SiO ₂ CaO Al ₂ O ₃ MgO MnO TiO ₂ Na ₂ O K ₂ O T.Fe FeO Cl SO ₃ ZnO NiO, Cr ₂ O ₃ , CuO, CdO, PbO, SnO, Sb are traces 33.13-34.75 41.15-43.16 9.82-14.60 7.03-11.55 0.05-0.53 0.63-1.85 0.1-0.15 0.27-0.55 0.30-1.68 0.32-0.97 0.0018-0.043 0.01-0.074 0.0015-0.020

Since blast furnace slag is composed mainly of CaO and SiO ₂ , there are few heavy metals that have harmful effects on the human body, and even if a small amount is present, it is composed of a stable compound because it is produced by slow cooling or rapid cooling from hot molten slag. It is a very stable raw material which does not change chemical and physical properties by reaction.

As shown in Table 1, the aggregated slag and the slag have no difference in chemical composition, but the slag is in an amorphous state and the aggregated slag is in a crystalline state. As such, the reclaimed slag may play an important role in developing late strength when used as aggregate because it has latent hydrophobicity as an amorphous material. Here, the latent hydraulic property refers to a property that the hydrated product is formed on the surface of the slag when the slag is in contact with water to condense and harden.

In the case where the applied slag is applied to the aggregate according to the present invention, the amount of the mixed slag in the aggregate is important. In the present invention, the mixing ratio of reinforcing slag is determined from aggregate based on a typical mixing ratio of cement and aggregate, for example, 1: 4 to 10.

In one embodiment, the aggregate slag in the aggregate is 10-90% by weight, and at least one or more of the remaining sand, stone powder, or aggregate slag is preferably 90-10% by weight. The mixing of the aggregate slag in the aggregate is more than 10% by weight in consideration of the object of the present invention for supplying a substitute for natural aggregate, and the mixing in the amount of 90% by weight or less is the compressive strength of the concrete secondary product specified in the KS standard. It is to be satisfied. Sand means here the natural sand used as a normal aggregate, and stone powder is also normally used as aggregate. The lump ash slag is crushed slag of the blast furnace described above and is crushed at a proper granularity. In the KS standard aggregate is used to satisfy the particle size of -0.15mm ~ -10mm, so the aggregate used in the present invention also uses that meets the KS regulations.

[Forming material using handmade slag and stainless slag]

According to the present invention, a molding material having an appropriate strength can be obtained even by using aggregate in which the handmade slag and the stainless slag are blended. Stainless slag is a slag from the stainless steel manufacturing process, and the chemical composition thereof is shown in Table 2 below.

Chemical composition (% by weight) SiO ₂ CaO Al ₂ O ₃ MgO MnO TiO ₂ Na ₂ O K ₂ O T.Fe 33.13-34.75 41.15-43.16 9.82-14.60 7.03-11.55 0.05-0.53 0.63-1.85 0.1-0.15 0.27-0.55 0.30-1.68

In the case of using the stainless slag as aggregate in accordance with the present invention, the mixing ratio of the aggregate is preferably set to 50% by weight or less and 50% by weight or more of the slag of the slag. The reason is that when the amount of the used slag is more than 50% by weight of the total aggregate, the crack occurs in the molded body and the product formation is bad, so that the defect rate is very high.

At this time, instead of a predetermined amount of stainless slag mixed with more than 50% by weight of the total aggregate, stone powder, sand, aggregate slag may be mixed at least one or more. In addition, stone powder, natural sand, lumped slag may be mixed with at least one kind instead of a predetermined amount of the hand-made slag mixed in less than 50% by weight of the total aggregate.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

Inventive Example (1-15)

For natural sand, stone powder, and -10mm blast furnace aggregate slag adjusted in size, adjust the mix ratio to 10%, 30%, 50%, 70%, 90% by weight of the total slag from the steelworks blast furnace. After adjusting the cement ratio to 10: 1, an appropriate amount of water was added, and the mixture was sufficiently mixed with an impller mixer. At this time, the weight of the total aggregate was 1000kg. Thereafter, cement bricks were molded at a pressure of 45 kg / cm ² , and then cured indoors under a condition of 50 ° C. × 10 hrs in a curing tank with a humidity of 98% or higher, followed by outdoor curing. After 7 days of outdoor curing, compressive strength and water absorption of cement bricks were measured and the results are shown in Table 2 below.

Comparative Example (1 to 3)

A brick was manufactured by the same method as the above-described invention except that 100% of the used slag was used as the aggregate, and the ratio of the aggregated slag to the handmade slag was changed to 1:10, 1: 6.7, 1: 4. The compressive strength and water absorption of bricks were measured and the results are shown in Table 2 below.

Conventional example (1)

A cement ratio of 1000 kg of natural sand aggregate was 10: 1, and an appropriate amount of water was added, and the mixture was sufficiently mixed with an impller mixer. Thereafter, cement bricks were molded at a pressure of 45 kg / cm ² , and then cured indoors under a condition of 50 ° C. × 10 hrs in a curing tank with a humidity of 98% or higher, followed by outdoor curing. After 7 days of outdoor curing, the compressive strength and water absorption of cement bricks were measured and the results are shown in Table 3 below.

As shown in Table 3, the bricks prepared according to the present invention (Inventive Examples 1-4, 6-9, 11-13) showed better physical properties than the bricks made of natural sand (prior example 1). The bricks of Inventive Example (5, 10, 14-15) were somewhat inferior in physical properties to the conventional bricks, but satisfied the physical properties (compressive strength of 80 kg / cm ² and absorption rate of 10% or less) specified in KS.

Example 2

Inventive Example (16-24)

Adjust the mixing ratio of the natural sand, stone powder and granulated slag from the steel mill to 10%, 50% and 90% by weight of the total aggregate, and adjust the cement ratio of the total aggregate to 5: 1. After adjusting to, an appropriate amount of water was added and mixed well with an impller mixer. At this time, the weight of the total aggregate was 1000kg. After that, the hollow concrete block was molded at a pressure of 45 kg / cm ² , and then cured indoors under the conditions of 50 ° C. × 10hr in a curing tank with a humidity of 98% or higher, and then outdoor curing was performed. After 7 days of outdoor curing, the compressive strength and water absorption of the block were measured and the results are shown in Table 4 below.

Comparative Example (4)

A block was manufactured in the same manner as in the invention example except that 100% of the handmade slag was used as the aggregate, and then the compressive strength and the water absorption of the block were measured and the results are shown in Table 4 below.

Conventional example (2)

The cement ratio of 1000 kg of natural sand aggregate was adjusted to 5: 1 and mixed with an impller mixer by adding an appropriate amount of water. After that, the block was molded at a pressure of 45 kg / cm ² , and then cured indoors under a condition of 50 ° C. × 10 hr in a curing tank having a humidity of 98% or higher, followed by outdoor curing. After 7 days of outdoor curing, the compressive strength and water absorption of the cement block were measured and the results are shown in Table 4 below.

As shown in Table 4, the block produced according to the present invention had physical properties equivalent to or higher than those of the conventional block.

Example 3

In the following examples, except for the mixing ratio of the aggregate, the manufacturing method of the brick is the same as that of Example 1, so only the mixing ratio of the embodiments is mentioned herein.

Inventive Example (25-27)

The stainless slag is adjusted to 10%, 30%, and 50% by weight of the total aggregate, and the cement to aggregate ratio is adjusted to 10: 1, and then the appropriate amount of water is added to the impller mixer. Mixing to prepare a binary mixed aggregate, and prepared a brick with this aggregate and then measured the compressive strength and absorption of the brick and the results are shown in Table 5 below.

Inventive Examples (28-29)

Adjust the mixing ratio to 30% and 50% of the handmade slag on the aggregate mixed with stainless slag and stone powder, prepare ternary mixed aggregate under the same conditions as above, and prepare the brick with the aggregate, and then compress the strength and absorption rate of the brick. Was measured and the results are shown in Table 5 below.

Inventive Example (30-31)

Adjust the mixing ratio to 30% and 50% of the hand slag on the aggregate mixed with stainless slag, stone powder, and -10mm aggregate slag, and to prepare the quaternary mixed aggregate under the same conditions as above, and then prepare the brick with the aggregate. The compressive strength and absorption rate of were measured and the results are shown in Table 5 below.

Comparative Example (5-7)

The mixing ratio was adjusted to 70% by weight ratio of the total aggregate of the male slag to the stainless slag, and a binary mixed aggregate was prepared under the same conditions as described above (Comparative Example (5)). In addition, the mixing ratio was adjusted to 70% by weight ratio of the total aggregate of the hand slag to the aggregate mixed with stainless slag and stone powder, and the ternary mixed aggregate was prepared under the same conditions as described above (Comparative Example (6)). In addition, a quaternary mixed aggregate was prepared such that the stainless slag, stone powder, -10mm aggregate slag was mixed to 70% by weight ratio of the total aggregate of the handmade slag (comparative example (7)).

After the brick was manufactured from the mixed aggregate, the compressive strength and the absorption rate of the brick were measured and the results are shown in Table 5 below.

As can be seen in Table 5, the brick composed of the hand slag and stainless slag was satisfied all the requirements of the brick.

As described above, the present invention can provide a molding material that can solve the supply and demand difficulties of the aggregate in accordance with the limit of the collection of natural aggregate, such molding material is brick, block, sidewalk block, road boundary stone, drainage pipe, central separator , Can be usefully applied to secondary concrete products such as manhole cover, landscaping stone.

Claims (4)

In the molding material composed of aggregate and cement, The aggregate is (a) wood slag: 10-90% by weight and (b) at least one of sand, stone meal or lumped slag: 90-10% by weight Molding material using handmade slag, characterized in that it comprises a mixture In the molding material composed of aggregate and cement, The aggregate is (a) wood slag: less than 50% by weight (b) Stainless slag: 50 wt% or more Molding material using the handmade slag and stainless slag, characterized in that it comprises a mixture. 3. The molding material according to claim 2, wherein the aggregate is mixed with at least one of stone powder, sand, and aggregated slag instead of a predetermined amount of stainless slag mixed at 50 wt% or more. 3. The molding material as claimed in claim 2, wherein the aggregate is mixed with at least one of stone powder, natural sand, and lumped slag instead of a predetermined amount of wood slag mixed at 50 wt% or less.