JPS605297A - Sludge solidifying agent - Google Patents

Abstract

PURPOSE:To achieve the enhancement in longterm strength and initial strength and the available utilization of quick lime dust, by containing a shaft furnace granulated slag fine power with a predetermined particle size, gypsum and quick lime dust in a predetermined ratio. CONSTITUTION:A sludge solidifying agent consists of 30-60pts.wt. of finely pulverized shaft furnace granulated slag with a specific surface area of 2,000- 4,000cm<2>/g, 20-45pts.wt. of gypsum and 15-40pts.wt. of quick lime dust prepared from a lime baking oven as a byproduct. This solidifying agent is high in longterm strength and initial strength and quick lime dust discarded by much effort is effectively utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a sludge assimilation agent, more specifically a granulated slag.
This invention relates to a solidifying agent based on granulated blast furnace slag, gypsum, and quicklime dust instead of gypsum and slaked lime based materials.

[Technical background of the invention and its problems]

Granulated blast furnace slag is produced by letting molten blast furnace slag, which is a by-product of a blast furnace in a steel mill, flow down through a tandigy, spraying it with pressure water, quenching it, and crushing it. This granulated blast furnace slag is glassy and has latent hydraulic properties that harden due to the presence of lime or gypsum. the result,
Traditionally, it has been used mainly as a raw material for blast furnace cement.

However, although assimilates using granulated slag have high long-term strength, they have the disadvantage of low initial strength. If the initial strength is low, it will hinder the running of a 1rI machine, for example, and cause a decrease in construction efficiency. Therefore, attempts have been made to add calcium chloride, etc. Although this method is certainly effective in improving initial strength, it often results in a decrease in long-term strength.

On the other hand, it has been conventionally known that a mixture of granulated blast furnace slag, gypsum, and slaked lime can solidify and stabilize sandy soil, silt, and the like.

In recent years, wood inventors have also revealed that highly water-containing clay soils, such as sludge, that far exceed the liquid limit have a solidifying and stabilizing effect.

Ettringite (3CaO
-A1203.3CaSO4.32H20) is dispersed and generated, which is thought to prevent the deformation of the clayey soil structure. Contains 65 to 95 parts of quicklime generated from furnaces), and has a particle size of 100. This quicklime dust is currently difficult to dispose of, as it is a powder of approximately 300 ml of water and elutes a high alkali when it comes into contact with rainwater, etc.Furthermore, this quicklime dust can be hydrated by mixing it with highly water-containing clay soil such as sludge. When turning into slaked lime, it absorbs water, generates heat, lowers the water content ratio, and exhibits a compaction effect, but quicklime dust alone cannot provide sufficient strength. On the other hand, quicklime is sometimes used for soil improvement, but when it is used as a slurry as in Example 2, the hydration rate is too fast and high strength cannot be obtained. [Objective'] The present invention solves the above-mentioned conventional problems, and provides a sludge solidifying agent that has the desired long-term strength, has excellent initial strength, and can effectively utilize quicklime dust. It is in.

[Summary of the invention]

The gist of the present invention to achieve this objective is that 2 (100 to 4
Granulated blast furnace slag pulverized to 30 to 000cra/g
The sludge assimilation agent is characterized in that it contains 60 parts by weight, 20 to 45 parts by weight of gypsum and 15 to 40 parts by weight of quicklime dust produced by lime kilns.

[Structure of the invention and its specific explanation]

In the present invention, three components, granulated blast furnace slag, gypsum, and quicklime dust, are used as main or all components.

The particle size of granulated blast furnace slag is 2000 to 4000 crl/
g is preferred. When adjusting the particle size, 200
If it is less than 0d/g, the hydration reaction of the granulated blast furnace slag will be too slow and the improvement in initial strength that is the objective of the present invention cannot be achieved, and if it exceeds 4o00ffl/7, the strength will be insufficient to meet the energy required for crushing. No improvement effect is seen0
Particularly preferred is 2500 to 3500 d/#0.30 to 60 parts by weight of granulated blast furnace slag is mixed. If it is less than 30 parts by weight, there is little soluble alumina required for the production of ettringite, so it is difficult to stabilize highly water-containing clay soil such as sludge. On the other hand, if it exceeds 60 parts by weight, the amount of gypsum and quicklime dust will be relatively small, resulting in a decrease in the amount of ettringite produced, which is also unsuitable for stabilizing sludge.

It is suitable to use 20 to 45 parts by weight of gypsum02
If it is less than 0 parts by weight, there will be less sulfate radicals required for IJ guide formation, and if it exceeds 45 parts by weight, the amount of granulated blast furnace slag and quicklime dust required for ettringite formation and improvement of initial strength will be reduced, making it unsuitable.

Quicklime dust is mixed in 15 to 45 parts by weight, but if it is less than 15 parts by weight, there is no effect of improving initial strength, and if it exceeds 40 parts by weight, the amount of other components required to develop long-term strength will be reduced.

On the other hand, in the present invention, as a source of slaked lime, quicklime dust with particularly low hydration activity is used. This quicklime dust is preferable because, as shown in Example 1 below, the water utilization reaction is slow. When it is added as a slurry, as in the case of sludge, hydration continues even after the disturbed sludge settles and re-forms its structure. This is thought to be due to the effective consolidation effect. On the other hand, although the use of quicklime powder has been considered, the hydration activity is high as shown in Example 2, but the method shown in Example 2, which uses the quicklime dust of the present invention, has high hydration activity. The effect of improving initial strength is small compared to the case where The reason for this is that water is used quickly and is added in the form of a slurry, so the hydration ends and breaks off, especially during kneading and while the structure of the kneaded sludge is disturbed, causing the above-mentioned effect to occur. [Example] Next, the present invention will be further explained with reference to an example.
0μ), quicklime dust (88μ) produced as a by-product from the lime kiln
Check the hydration activity of each of the sieve residue (45) using the following steps 1 to 2.

■ Take 50 ml of pure water in a 200 ml beaker and add a few drops of phenolphthalein. ■ Start stirring with a stirrer. ■ Add lime to a temperature of 0.591 degrees. ■ Immediately, the liquid will become slightly Add 0.4 N hydrochloric acid solution to maintain the red color, and read the amount added every 30 seconds. The results are shown in Figure 1, and the hydration activity of the quicklime duct is comparable to that of quicklime and slaked lime. It can be seen that it is low compared to 0 (Example 2) Liquidity limit 136%, Japanese unified classification CI (frontage of sludge with a water content ratio of 263) x depth 1 x depth 1.3 m
3. Enter the pool up to a height of 1m from the bottom. oooCr
? L/,! A mixture of i+ granulated blast furnace slag: flue gas desulfurization stone g: slaked lime source = 5:3:2 was added and mixed with 7% to the M and t of sludge.The slaked lime source used was the quicklime used in Example 1. , slaked lime, and quicklime dust. From this sample, the sludge that had hardened on the 14.28th day of 3.7° was sampled and its unconfined compressive strength was measured.

The results are shown in Figure 2, and the sludge added with the mixture using quicklime dust showed a remarkable increase in initial strength at 3 and 7 days of age, compared to when other slaked lime sources were used. It is around 1 to 1 which is said to be drivable.

〔Effect of the invention〕

As described above, according to the present invention, the 2'L can achieve the desired long-term strength and improve the initial strength by 2'L, which is particularly effective for sandy soil systems, and which is difficult to dispose of. It is possible to make effective use of quicklime dust.

[Brief explanation of the drawing]

FIG. 1 is a correlation diagram showing the hydration activity overlay test results of slaked lime sources, and FIG. 2 is a correlation diagram showing changes in strength over time of slaked lime sources.

Claims (1)

[Claims] (1) 30 to 60 parts by weight of granulated blast furnace slag pulverized to 2000 to 400 OCrv, 20 to 45 parts by weight of gypsum, and 15 to 15 parts by weight of quicklime dust from lime kilns.
A sludge solidifying agent characterized by containing 40 parts by weight and a total of 100 parts by weight.