JPS62247882A - Production of solidifying agent - Google Patents

Abstract

PURPOSE:To prepare a solidifying agent which has a high rate of solidification, is weakly alkaline and acts as a replacing material for cement by mixing a material prepd. by subjecting blast furnace water granulated slag and gypsum of stack gas desulfurization to an exposure treatment in an ozone atmosphere with Mg, CaCl2, cement, Ca hydroxide, etc. CONSTITUTION:Pulverized powder of the blast water granulated slag and pulverized powder of the gypsum of the stack gas desulfurization are subjected to the exposure treatment for the specified time in the ozone atmosphere and 20-50wt% pulverized powder of the gypsum of the stack gas desulfurization obtd. by subjecting the powder to the ozone treatment thereof, 1-4wt% Mg, 1-5wt% CaCl2, either one or both of 1-5wt% cement and 0.1-0.5wt% Ca hydroxide and the pulverized powder of the blast furnace water granulated slag subjected to the ozone treatment and corresponding to the balance are mixed. The solidifying agent obtd. in such a manner has the high rate of solidification, is weakly alkaline, does not generate environmental pollution, has the substantial mechanical strength of the solidified matter and is usable as a replacing material for cement.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a solidifying agent mainly composed of blast furnace water slag and expelled gypsum, and is useful for improving soft ground, assimilating sludge, and cement. It is mainly used as an admixture and a substitute for cement.

(Conventional technology) In order to improve soft ground and solidify sludge, blast furnace water slag is traditionally burnt and crushed, and a small amount of hydraulic inorganic material is added to it to activate the hydraulic properties of blast furnace water slag. Solidifying agents produced by mixing are widely used, and solidifying treatment is performed by mixing a mixture of the solidifying agent and cement milk into soft soil or sludge and stirring. The solidifying agent is
When the lime glass in the blast furnace water slag reacts with the hydroxide lime in the mortar, lime silicate and lime aluminate, which are similar to the main compounds of Portland cement, are produced, which exhibits hydraulic properties and is dense. This increases the assimilation strength by forming a hydrated tissue.

However, the solidifying agent produced from the blast furnace water slag usually needs to be mixed with cement milk at a ratio of about 1:1, and if the mixing ratio of cement milk is reduced, a sufficient solidifying effect cannot be obtained. Therefore, in actual use, a large amount of cement is required, and ground improvement costs and sludge treatment costs are high.
The problem is that it can affect the kidneys.

Further, the solidifying agent requires a considerable curing period to complete solidifying, and the compressive strength of the assimilate is not sufficiently increased. For example, water content 120%, specific gravity 1.
45? 1 door of /l- silty clay and 120 KI of mixed milk in which the solidifying agent and cement milk are 1=1? When mixed, the indoor-axial compressive strength after 30 days is 2-3K
g/crI (15 to 17 in the case of 300 kg contamination)
Kg/cy & ), and requires a long curing period and large amounts of solidification agent and cement milk to increase the assimilation strength.

On the other hand, it has been known that blast furnace water slag undergoes a hydration reaction with gypsum in the presence of an alkaline stimulant and has the effect of solidifying soft soil and the like. That is, the alumina component in the blast furnace water slag undergoes a hydration reaction with gypsum due to the action of alkaline reaction accelerators such as cement and slaked lime, producing so-called hardened IJ ngite, which solidifies soft soil, etc. .

However, with solidifying agents manufactured using cement or slaked lime as stimulants, even if the amount of stimulant is increased (15 to 20% by weight), the hydration reaction between alumina and gypsum is extremely slow, and solidification takes a considerable amount of time. Moreover, there are disadvantages in that the solid matter is strongly alkaline and the compressive strength of the solidified product is extremely low.

In addition, in order to increase the hydration reaction rate between alumina and gypsum, potassium hydroxide (KOH) and sodium hydroxide (Na
OH) and other strong alkaline substances are being used as stimulants to develop methods for producing assimilation agents. However, even in this case, 15 to 20% by weight of a strong alkaline stimulant is required to promote the hydration reaction (the reaction rate will be saturated even if more is added), and as a result, the alkalinity of the solidified product will be reduced to PT (l Directly 10-1
This results in alkaline contamination of the soil and ground, and in the case of sludge treatment, there is a risk of secondary contamination due to assimilated sludge waste. Furthermore, the solidifying agent produced by the above manufacturing method has a low compressive strength of the solidified product, and there is a risk of cracking due to the reaction with the alkali aggregate, so it is completely impossible to use it for construction purposes as a replacement for the 7-mention material. It is.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems with conventional solidifying agents mainly composed of blast furnace water slag, namely: (1) the solidification time is considerably long (2) the compressive strength of the solidified product is Solved the problems such as: - The solidified product is strongly alkaline, causing environmental pollution; - Due to its strong alkalinity, the mechanical strength of the solidified product is low, and it cannot be used as a cement substitute. Production of a solidifying agent that has a fast assimilation rate, is weakly alkaline, does not cause environmental pollution, and has sufficient mechanical strength as a solidified product, and can be used as a substitute for cement. The purpose is to provide a method.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present inventor has proposed the following: ■ By adding other substances to the alkaline stimulant, a stronger water can be produced with a smaller amount of the alkaline stimulant. The idea was to increase the sensitivity to stimulants and promote the hydration reaction by activating the main components, blast furnace water slag and expelled gypsum itself. Regarding combinations of alkaline stimulants and additives, we conducted numerous solidification tests using their mixing ratios and the mixing ratios of blast furnace slag and removed gypsum as parameters, and also investigated the activation of blast furnace water slag and removed gypsum by ozone. Various tests were conducted regarding the chemical treatment.

The present invention was created based on the above idea and various tests based on the idea, and the present invention exposes fine powder of blast furnace water slag and flue gas desulfurization gypsum in an ozone atmosphere for a certain period of time, and then processes it for 20 days. ~50% by weight of fine powder of ozonated flue gas desulfurization gypsum, 1 to 4% by weight of magnesium,
1 to 5% by weight of calcium chloride, 1 to 5% by weight of cement and 01 to 05% by weight of hydrated calcium, either one or both, and the balance equivalent to fine powder of ozonated blast furnace slag. A method for producing a solidifying agent, which comprises mixing.

(Function) The solidifying agent produced according to the present invention basically promotes the hydration reaction between the alumina component in the blast furnace water slag and gypsum with an alkaline stimulant, and by producing hardened ettringite, the solidifying action is odorless. It is assumed that In addition, when used in combination with cement, etc., the high lime glass in the blast furnace water slag reacts with the hydroxide lime in the cement to produce lime silicate and lime aluminate, which are similar to the main compounds of cement. However, the hydraulic action caused by these is superimposed on the assimilation action.

By adding a small amount of magnesium and calcium chloride to an alkaline stimulant such as cement or calcium hydroxide, the stimulant is further activated, its ability to promote the hydration reaction is improved, and the formation of the hardened ettringite product is promoted. Assimilation time is shortened and the mechanical strength of the solidified product is also improved.

In addition, by exposing the main components of removed gypsum and blast furnace water slag to an ozone atmosphere, the alumina components in the gypsum and water slag are activated, and together with the action of the stimulant, the It is assumed that the production of 1-IJ ngite is further promoted and a denser hydrated structure is formed, thereby achieving a significant improvement in the mechanical strength of the solidified product.

(Example) Hereinafter, the present invention will be explained in detail based on one embodiment of the present invention.

Blast furnace slag is produced by rapidly cooling molten blast furnace slag discharged from a blast furnace with fresh water or seawater, then drying it and pulverizing it (particle size 5
~3011m). The pulverized blast furnace water slag is subsequently introduced into an ozone generator, where it is exposed to an ozone atmosphere for a certain period of time. The ozone exposure treatment is performed by dropping fine slag powder along a zigzag chute from top to bottom inside the ozone generator, and the residence time of the fine powder in the ozone atmosphere is is 10 to 20 seconds, the power of the ozone generator light source is 2KW x 10 units, and the processing capacity of fine slag powder is 1
0-15 Kg/min. In addition, as a blast furnace amphibious land,
It is preferable to use molten blast furnace slag quenched with fresh water, and the exposure treatment in an ozone atmosphere is as follows:
Retention for about 0 to 20 seconds is sufficient, and even if the ozone treatment is further strengthened, no significant change is observed in the increase in mechanical strength of the solidified product.

Table 1 shows the chemical components of the blast furnace slag used in this example.

Table 1 Chemical composition of blast furnace water slag (wt%) On the other hand, flue gas desulfurization gypsum is manufactured by drying and finely pulverizing (particle size 5 to 20 μm) desulfurized gypsum from heavy oil-fired thermal power plants. , has chemical components as shown in Table 2. Further, as in the case of blast furnace water slag, the removed gypsum is subjected to a bleaching treatment in an ozone atmosphere after drying and pulverization, and the ozone treatment conditions are the same as in the case of the blast furnace water slag.

Table 2 Chemical components (wt%) of flue gas desulfurization gypsum Tables 3 and 4 show the mixing ratio of each component of the solidifying agent produced in this example.

Table 3 Components of solidifying agent (wt%) Table 4 Components of solidifying agent (% by weight) Cement and calcium hydroxide constitute the main irritants, and when cement is used alone, the amount of 1 to 5 w
t% addition is required. If the cement content is less than 1 wt%, the hydration reaction between alumina and gypsum in the blast furnace water slag will not be promoted, and if the cement content exceeds 5 wt%, not only will the alkalinity of the solidified product increase, but the hydration reaction will be accelerated. This is because the reaction promoting effect is saturated, and a mixing ratio of 1 to 3 wt% is most suitable.

The same is true when calcium hydroxide is used as the main stimulant; below 0.1 Wt%, the hydration reaction is too slow, and above 0.5 Wt%, the alkalinity of the solidified product is low. This is because the reaction rate does not improve much as the amount increases, and a mixing ratio of 01 to 0.2 Wt% is the optimum value. In this example, cement and calcium hydroxide are used alone, but they can be used together, for example, cement l-Iwt% and calcium hydroxide O,
Of course, 1 wt% may also be used.

Magnesium and calcium chloride serve a supplementary function to the main stimulant, activate the main stimulant, and significantly promote the hydration reaction by acting synergistically with the main stimulant. In addition, in order to promote the hydration reaction, magnesium should be added at 1 to 4 wt% (optimal value is 1 to 2 wt%) and calcium chloride should be added at 1 to 5 wt% (optimal value is 1 to 3 wt%).
each is required, and if either falls below its minimum value, the promoting effect decreases. Furthermore, when the amounts of magnesium and calcium chloride exceed 4 and 5 wt%, respectively, the effect of promoting the hydration reaction is saturated. Therefore, the respective addition amounts are 4 and 5 W
t% or less.

Ozone-treated degassed gypsum and ozone-treated blast furnace water slag are the basic components of the solidifying agent, but the ratio of the two (blast furnace water slag/degassed gypsum) is about 1 to 4. is suitable, and preferably 12 to 20 is optimal. Even if the amount of gypsum is insufficient and becomes less than 20 wt%, or even if the amount of gypsum exceeds 50 wt% and the blast furnace water slag becomes insufficient, the solidifying performance and solidifying strength of the solidifying agent will decrease. Therefore,
In this embodiment, the amount of removed gypsum is 20 to 50 wt%, and the remainder after removing the stimulant and activator is blast furnace water slag. The ratio of the amount of blast furnace water slag to the amount of gypsum is based on theory (including one shift, which is considerably larger than the direct shift), but the reactivity of the alumina component in the blast furnace water slag to the removed gypsum (dihydrate gypsum) is Since it is related to the solubility of gypsum, it has been confirmed that extremely good solidification properties can be obtained even if the amount of gypsum is considerably less than the theoretical value.

FIG. 1 shows the solidification test results of the solidifying agent produced according to the present invention as shown in Table 3, and curve A relates to the solidifying agent according to the present invention.

Curve B is for the case where blast furnace water slag and gypsum, which have the same chemical composition and have not been subjected to ozone treatment, are used, and both have a different mixing ratio of solidifying agent and water (solidifying agent/water). 1.
This is the value when it is set to 7.

In the case of the solidifying agent produced according to the present invention, the compressive strength is 200 KF 7 days after mixing! /7.330 Kg/d in 14 days
.

It becomes 54.0 K9/7 in 28 days, and has approximately the same assimilation rate and compressive strength as Portland cement.

Furthermore, it has been found that the compressive strength is improved by about 30% compared to the case where the blast furnace water slag and gypsum are not subjected to image treatment using an ozone atmosphere.

The alkalinity of the solidified product by the solidification agent is PH85, which is a weak alkalinity close to neutrality, and the alkalinity is significantly lower than that of the conventional cement-based hardening agent whose main ingredient is blast furnace water slag.

Furthermore, using the solidifying agent produced according to the present invention, the water content ratio is 12.
0%, specific gravity 1.45 K, / 7 silty clay 1
When 120:9 of molten milk of the solidification agent is mixed with Go, 3
After 0 days, the indoor-axial compressive strength is 6 to 7 Kg/cd, which improves the compressive strength of the solidified material by 30 to 40% compared to the conventional cement-based solidifying agent that mainly uses blast furnace water slag, and also reduces the assimilation time. is also significantly shortened.

(Effects) The solidifying agent according to the present invention is made by exposing the main components, blast furnace water slag and expelled gypsum, in an ozone atmosphere for a certain period of time, so that both are activated and less irritants are used. As the hydration reaction progresses rapidly, a dense hydrated structure is formed. As a result, the assimilation rate and compressive strength of the solidified material are significantly improved.

Further, since the solidifying agent according to the present invention significantly enhances the effect of promoting the hydration reaction of the alkaline stimulant by adding magnesium or the like, a rapid solidifying effect can be achieved with a small amount of the alkaline stimulant. Therefore, even if soil improvement treatment or sludge assimilation treatment is performed using the solidification agent, so-called alkali pollution will hardly occur, and the time required for solidification work will be significantly shortened, improving work efficiency. Improvements can be made.

Furthermore, the solidifying agent according to the present invention has approximately the same assimilation rate and compressive strength of the solidified product as Portland cement, and can be used for building materials as a cement substitute. There is almost no possibility that cracks or the like will occur in the structure due to the reaction.

Furthermore, the present invention aims to effectively utilize blast furnace water slag and removed gypsum, and has superior effects in terms of resource saving and low cost compared to conventional cement or cement-based solidifying agents.

As mentioned above, the present invention has high practical utility.

[Brief explanation of drawings]

FIG. 1 shows the curing and strength properties of the solidifying agent of the present invention. A Characteristic curve of the solidifying agent according to the present invention. B Characteristic curve of a solidifying agent using blast furnace land and land and gypsum, which have the same chemical components as those of the present invention but have not been subjected to ozone bleaching treatment. 0 yen 1st

Claims (1)

[Claims] (1) The fine powder of blast furnace water slag and the fine powder of flue gas desulfurization gypsum are exposed in an ozone atmosphere for a certain period of time, and then
% by weight of ozone-treated flue gas desulfurization gypsum fine powder, and 1
-4% by weight magnesium, 1-5% by weight calcium chloride, 1-5% by weight cement and 0.1-0.5% by weight
1. A method for producing a solidifying agent, which comprises mixing one or both of calcium hydroxide in a weight percent and the balance of fine powder of ozone-treated blast furnace slag.