JPH02243553A - Production of formed body using steel slag as binder - Google Patents

Abstract

PURPOSE:To produce a high-strength formed body using steel slag as a binder by adding specific amounts of an alkali metal hydroxide and alkali metal carbonate as an aqueous solution to specified fine steel slag powder and kneading a paste, etc., therewith. CONSTITUTION:An alkali metal hydroxide in an amount of 1-30wt.% and an alkali metal carbonate in an amount of 1-30wt.% are added to fine steel slag powder having 5,000-8,000cm<2>/g Blaine specific surface area and the resultant mixture is kneaded with a paste, mortar or concrete. In the process, at least the alkali metal hydroxide as an aqueous solution is added thereto. The resultant kneaded mixture is formed and then hardened. Thereby, the steel slag can be effectively utilized to afford high-strength formed body using the steel slag as a binder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a molded product using steel slag as a binder, more specifically,
af/g fine powder of steel slag as an aqueous solution and knead it into paste, mortar, or concrete (hereinafter collectively referred to as concrete, etc.) to increase the strength of the hardened product. The present invention relates to a method for manufacturing a molded body using steel slag as a binding material.

[Prior art and problems with the invention]

Traditionally, steel slag such as blast furnace slag or converter slag has been produced in large quantities as an industrial by-product, but its uses are limited to being used as a raw material for cement production or for producing blast furnace cement and aggregate. Most of the waste is dumped in landfills without being put to effective use. Recently,
It has been proposed to add gypsum, quicklime, etc. to steel slag to increase its hydraulic properties and make it into cement.
Since its strength is not sufficiently developed, a satisfactory molded product using steel slag as a binder has not yet been obtained.

[Means to solve the problem]

In order to solve this drawback, the present inventors added a small amount of alkali metal hydroxide and alkali metal carbonate to fine steel slag powder with a plain specific surface area of 5,000 to 8,000 cilg, and kneaded it into concrete, etc. At that time, if at least the alkali metal hydroxide is added as an aqueous solution,
It was discovered that the strength of the cured product of the kneaded product was significantly increased, and the present invention was proposed.

That is, the method of the present invention has a plane specific surface area of 5000 to 8
000cn! /H steel slag fine powder, 1 to 3
When kneading concrete, etc. by adding 0% by weight of alkali metal hydroxide and 1 to 30% by weight of alkali metal carbonate, at least the alkali metal hydroxide is added as an aqueous solution, and the kneaded product is mixed. It is characterized by being cured after being molded.

The method of the present invention will be explained in detail below.

Iron and steel slag is a by-product during iron and steel manufacturing, and to give an example of its chemical composition, blast furnace slag is 51023
2-36%, 81□0312-20%, CaO35-4
3%, Mg[]00.5~10%7102 0.1~3
%, converter slag is 5i025~20%, Al2
O30,3~2%, FeO3~25%, Fe2O,3~
15%, Ca030-55%, and Mg01-8%, and in the method of the present invention, steel slag having such a chemical composition is used as a raw material.

Normally, iron and steel slag can be manually processed as granules with a particle size of several mm to several tens of mm, but it is important to grind it into a fine powder before use. In this case, grinding aids such as diethylene glycol and triethanolamine, as well as concrete materials used as cement dispersants, such as lignin sulfonate, β-naphthalene sulfonic acid formalin condensate salt, and sulfonated melamine, are used. Basically, all of them are product names, but if you crush them together with "Hozolith" (manufactured by Old Master and Ruders), "Mighty" (manufactured by Kao Soap), and "Melment" (manufactured by Showa Denko), etc. This is a preferred pulverization method because it further increases the strength. As for its fineness, the strength increases as it increases, but the compressive strength at one day of age is 3,000 in dulane specific surface area.
When it exceeds 0 crl/g, it increases significantly, but in the present invention, from the viewpoint of the compressive strength of the compact, the iron and steel slag crushing device, the crushing time, etc., it is 5,000 to 8,000
A plane ratio within the range of cd/g is used.

In the method of the present invention, an alkali metal hydroxide and an alkali metal carbonate are added in order to further increase the activation of the steel slag and develop high strength. The addition ratio of the alkali metal hydroxide to the steel slag is 1 to 30% by weight; if it is less than 1% by weight, the strength enhancement effect is small, and if it is added in excess of 30% by weight, there is not much advantage. On the contrary, the alkali becomes strong and becomes impractical. The preferred amount added is 5 to 15% by weight.

Specific examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, and lithium hydroxide. Among these substances, there is almost no difference in their strength-enhancing effects, but they are difficult to obtain. Sodium hydroxide is the most preferred because of its ease of use.

Further, the addition ratio of the alkali metal carbonate is 1 to 30% by weight, preferably 2 to 10% by weight based on the steel slag, and if the addition amount is less than 1% by weight, there is no effect of improving long-term strength. Further, there is no advantage in terms of strength development when adding more than 30% by weight. Specific examples of carbonates of alkali metals include carbonates of potassium, sodium, lithium, etc. Among them, sodium carbonate has the best strength development. These do not necessarily need to be added as an aqueous solution.

In the present invention, the method of adding the alkali metal hydroxide is particularly important and has a great influence on strength development.

For example, compared to adding it in advance to steel slag or adding it in powder form during mixing of concrete, etc., when added dissolved in the water used during mixing, the openness strength increases by approximately 2. , the alkali metal hydroxide is preferably added as an aqueous solution, and desirably,
Dissolve the entire amount in the water used and add.

In this way, the kneaded material to which alkali metal hydroxide and alkali metal carbonate are added develops significantly high strength by curing, and in particular, the initial strength at about one day of age increases significantly. The long-term strength will also increase.

The materials described above are used and mixed with sand, gravel, reinforcing fibers, etc. as necessary to mix concrete, etc. At that time, hardening materials, such as those used as additives for Portland cement, are mixed. Addition of accelerators, setting retarders, foaming agents, expansion agents, etc. will produce corresponding effects.

Curing after forming a mixed material such as concrete can be the same as the curing method for a molded object using ordinary Portland cement as a binder, and can be selected as appropriate depending on the product, such as leaving it outdoors, accelerated curing by heating, etc., or high-temperature and high-pressure curing. be done.

The present invention includes, for example, piles, balls, pipes, U-shaped grooves,
It is applied to the production of molded bodies similar to Portland cement, such as box culverts, tetrabods, blocks, asbestos slates, lightweight bodies, and fiber reinforced bodies.

As explained in detail above, in producing a molded product using steel slag as a binder, the present invention provides a process in which specific amounts of alkali metal hydroxide and alkali metal carbonate are mixed into concrete or the like, and in particular, at least alkali metal water The oxide is added as an aqueous solution to mix concrete, etc., and harden it.According to the present invention, it is possible to manufacture a molded product with the same strength as Portland cement using steel slag itself. It is revolutionary in that it has become
In addition, it has the secondary effect of making it possible to effectively utilize industrial by-products.

Hereinafter, the present invention will be explained in more detail with reference to examples.

Example 1 Plane specific surface area having the chemical composition shown in Table 15.
To 100 parts by weight of 0.70 cm2/g granulated blast furnace slag, 10 parts by weight of hydroxide (IJium) and sodium carbonate are added and a paste is kneaded, but at this time, the entire amount of sodium hydroxide is dissolved in the water used. For the case where it is added as a powder and the case where it is added in solid form to granulated blast furnace slag powder in advance, a paste with a W/C of 30% is kneaded and poured into a 2 x 2 x 8 cm mold to prepare a paste specimen. did. The compressive strength of this material was measured after it was cured for 28 days in a room with 80% RoH at 20.degree. C. and at 1 day after being steam-cured at 60.degree. C. for 6 hours. Table 2 shows the results.
Shown below.

Table 1 Example 2 Additives in the proportions shown in Table 3 were added to 100 parts by weight of blast furnace water slag used in Example 1 in order to investigate the effect of different addition ratios of sodium hydroxide and sodium carbonate. Then, in the same manner as in Example 1, 2 X 2 X 8 c
A specimen of m was prepared and heated in a room with
After curing for 8 days, the compressive strength was measured (tests Nα5 to Nα1
4) Also, plane specific surface area 6,600 (test Nα1
5) a, ooo<Test Nα16) blast furnace water slag slag and for comparison 4.070 (Test N1117)
8,900 (test Nal 8) was used for the same test. The results are shown in Table-3.

Test N (L5, 9. I 7. 18 (H#c exists.

* Addition of IJium (carbonate) in solid form instead of sodium hydroxide The results in Table 3 show that adding sodium hydroxide in the form of an aqueous solution produces excellent effects, and in Tests Nα6 and 17. Plain specific surface area from comparison 5.
It can be seen that those with a plain ratio of more than 8.000 are more effective than those with less than that, and from the comparison of Test N (116 and 18), those with a plain ratio of more than 8.000 are not more effective compared to the amount of grinding. .

Patent applicant: Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1 to 30% by weight of alkali metal hydroxide and 1 to 30% by weight of alkali metal carbonate are added to fine steel slag powder with a plain specific surface area of 5000 to 8000cm^2/g to form paste, mortar or concrete. A method for producing a molded body using steel slag as a binder, characterized in that at least an alkali metal hydroxide is added as an aqueous solution when kneading, and the kneaded product is molded and then hardened.