JPH04292443A - Slag powder treated with polyhydroxyl group-containing substance - Google Patents

Abstract

PURPOSE:To stabilize slag of pig iron useful as a raw material for composite material and to obtain products having properties free from deterioration with time. CONSTITUTION:Slag such as blast furnace slag is treated with a polyhydroxyl group-containing substance to prevent integration of harmful ion such as Ca<++> into a hardening process. Consequently, the treated slag powder will not cause hardening reaction even after allowing to stand for many hours and becomes a composite material not reducing flexibility even in a state mixed with an organic binder such as chlorinated polyethylene, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to slag powder which is made from slag discharged from ironworks, such as granulated blast furnace slag, and which is mixed into various base materials as a filler.

0002

2. Description of the Related Art Inorganic products such as slate boards and gypsum boards are relatively light and hard materials, so they are used in various fields including building materials. In addition, organic products such as vinyl chloride sheets are used in forms that take advantage of their excellent properties such as flexibility, waterproof performance, and weather resistance.

However, inorganic products have a high water absorption rate and are not suitable for bending. Moreover, when used as a sound insulation material that takes advantage of its surface density, due to its high hardness, a coincidence effect occurs in which the sound insulation performance deteriorates in the high frequency range. On the other hand, organic products have problems in flame retardancy, and moreover, tend to generate large amounts of harmful gases such as chlorine when burned. In addition, many of them have low density, and when used for sound insulation purposes, it is necessary to construct them quite thickly. In this regard, it is known to mix an inorganic filler as a means of improving properties such as fire retardancy and sound insulation.

[0004] Bonding of granulated blast furnace slag using a synthetic resin as a binder has been proposed in Japanese Patent Application No. 59-214990. However, according to conventional methods, for example, when vinyl chloride and calcium carbonate are used as a binder and an inorganic filler, respectively, 2
Only about 50 parts of the inorganic filler is blended.

[0005] Therefore, the present inventors conducted research on materials containing this type of filler, and achieved a higher filling rate than before.
Furthermore, we are developing composite materials that make it possible to use industrial waste such as granulated blast furnace slag as a filler. As part of this effort, we discovered that when granulated blast furnace slag powder is blended with chlorinated polyethylene, a highly flexible composite material can be obtained even though it is blended at a significantly higher filling rate than conventional methods. A patent application was filed. This composite material can contain up to 1,400 parts by weight of granulated blast furnace slag per 100 parts by weight of chlorinated polyethylene, and has excellent flexibility, water absorption resistance, sound insulation, flame retardancy, etc.

[0006]

It has been observed that the newly proposed composite material exhibits a tendency to harden in harsh humid environments. In particular, it has been experimentally determined that there are significant differences in the curing of composite materials depending on the type of stabilizer added to prevent deterioration of the chlorinated polyethylene. For example, when 10 parts by weight of MgO is mixed as a stabilizer, the slag filling amount is 600 parts by weight, 800 parts by weight, 1000 parts by weight, 1 part by weight under conditions of 98% humidity and 50°C.
All of the 300 parts by weight cured to a level where practical flexibility was lost in about 100 to 200 hours. Other experiments were conducted using 10 parts by weight of calcium, barium, lead, tin, epoxy, etc. as stabilizers, and with no stabilizer added, but the hardening level was lower than that of MgO addition. Both values were lower than that of the previous case, and it was judged that it could withstand use in a normal indoor environment. However, it has been found that all of the latter have a tendency to cure upon wetting to a greater or lesser degree. In addition, granulated blast furnace slag contains 3 to 8% M.
Although it contains gO, it is a well-established theory that this MgO is not in a free state.

[0007] Therefore, in order to make the composite material usable in any harsh humid environment, the granulated blast furnace slag itself is chemically treated so that it can be hardened regardless of the harsh humid conditions or the presence of stabilizers. The challenge was to create a slag powder that would not If such slag powder can be obtained, Mg, which is commonly used as an inexpensive resin stabilizer, can be used.
It also becomes possible to use O.

[0008] This property deterioration occurs not only when granulated blast furnace slag is blended with chlorinated polyethylene as a filler, but also when it is used as other fillers. Similar problems also occur when using materials other than granulated blast furnace slag, such as steelmaking slag.
Products with reliable physical properties cannot be obtained.

The present invention was devised to solve these problems, and by treating slag powder with a substance containing polyhydroxyl groups, it is made into a raw material powder with stable properties, which can be used as a filler, etc. The purpose is to obtain a product that does not deteriorate in properties when used.

0010

[Means for solving the problems] The slag powder of the present invention is
To achieve this purpose, we have developed a slag powder treated with a polyhydroxyl group-containing substance, which is obtained by immersing the powder obtained by crushing blast furnace slag or steelmaking slag in an aqueous solution of the polyhydroxyl group-containing substance and then drying it. be.

[0011] Examples of polyhydroxyl group-containing substances include maltose,
These include tannic acid, polyacrylic acid, pectic acid, and sucrose.

0012

[Function] The cause of the hardening phenomenon that occurs in composite materials made of chlorinated polyethylene mixed with granulated blast furnace slag as a filler is unknown, but the inventors believe that it is caused by the latent hydraulic properties of the slag. Ta. Latent hydraulicity refers to the property of a material that does not harden easily even when water is added to it, but hardens when exposed to a certain level of alkaline stimulation. As a result of intensive study on means for preventing hardening, it was discovered that treatment with a polyhydroxyl group-containing material is very effective.

[0013] Substances containing polyhydroxyl groups contain a large number of O in one molecule.
It is a substance containing H groups, such as maltose, which has 8 OH groups. Maltose has the chemical formula C12H22O
11, and the weight proportion of the OH group in one molecule is 4.
It can be as low as 0%. Including other chemicals, the substances shown in Table 1 are listed as usable polyhydroxyl group-containing substances.

[0014]

[Table 1]

In the polyhydroxyl group-containing substance, some of the OH groups dissociate in an aqueous solution to become O-...H+, and some become undissociated -O
It exists as H. Therefore, the aqueous solution exhibits weak acidity. It is unknown which ions contribute to preventing hardening, but Ca++ decomposed and eluted from the slag, which is usually thought to be the cause of hardening, is attracted by Coulomb force to O- or -OH and is held there. It is thought that the transition to the curing process is physically inhibited. Furthermore, it is thought that this restriction on Ca++ suppresses changes in the properties of the slag powder even when it is used as a material other than a filler.

[0016]

[Example] The following experiment was conducted to investigate the curing prevention performance of polyhydroxyl group-containing substances. A suspension was prepared by taking 50 g of granulated blast furnace slag as a sample, adding 150 ml of water, and further adding 1 g of a predetermined polyhydroxyl group-containing substance. Then, the polyhydroxyl group-containing substance is dissolved by stirring the suspension, and after leaving it to stand, 1 part of caustic soda is added as a hardening accelerator.
g was added thereto, and the mixture was stirred again and allowed to stand still. After a predetermined period of time had elapsed, the hardening state of the slag was examined. Table 1 shows the results. The curing status was determined by stirring with a metal spatula, and those that could be stirred were evaluated as ○, and those that were solidified and could not be stirred were evaluated as ×.

[0017]

[Table 2]

As shown in Table 2, when no polyhydric group-containing substance was added, the slag exhibited a hardened state after 48 hours. On the other hand, when the polyhydroxyl group-containing substance was added at a concentration of 2%, the slag was not hardened even after 960 hours. However, the amount of polyhydroxyl group-containing substances added is 0.1%.
When the amount was less than that, curing was observed after 96 hours.

[0019] As described above, polyhydric acid group-containing substances are effective in preventing hardening of slag. Therefore, a composite sheet was created using granulated blast furnace slag powder treated with a polyhydroxyl group-containing substance using the following procedure. First, a polyhydroxyl group-containing substance corresponding to 2% by weight of granulated blast furnace slag powder was measured and an aqueous solution was prepared. Slag was added to this aqueous solution, and after stirring, water was evaporated and the powder was dried. Next, 1000 parts by weight of the above-treated dry slag powder and 10 parts by weight of an MgO-based stabilizer were mixed with the chlorinated polyethylene while passing it through a roll press machine. By repeating this operation 15 to 20 times, a sheet with a thickness of 3 mm was manufactured.

The mixed raw material was in a slightly brittle state during the pressing operation, but as the process was repeated and homogenized, it returned to a softened state and a flexible composite material was obtained. At this time, heat generation was generated that had an adverse effect on the roll press operation, so cooling water was passed through the roll to maintain the temperature at 60 to 80°C.

The flexibility of the produced composite sheet was examined in a constant temperature and humidity atmosphere of 50° C. and 98% RH. The results are shown in FIG. 1 in comparison with sheets similarly made from untreated powder. In addition, flexibility is determined by needle diameter 1.
A 0 mm rheonometer was pierced into the test piece to a depth of 1.5 mm, and the maximum resistance value at that time was evaluated. Figure 1 shows
It is a graph showing the maximum resistance value measured in this manner in relation to elapsed time.

As is clear from FIG. 1, the composite sheet manufactured using slag treated with a polyhydric acid group-containing substance does not undergo a curing reaction even after a long period of time and maintains excellent flexibility. I understand that. In contrast, the flexibility of the composite sheet using untreated powder deteriorated as the wet test progressed.

The slag powder treated according to the present invention is
In addition to the above-mentioned use as a composite sheet, it can also be used as a filler for various coating materials. For example, when kneaded with a binder such as a water-soluble resin, a coating agent with excellent fire resistance can be obtained. At this time, the slag powder of the present invention has a long pot life and exhibits stable properties over a long period of time. Also, additives for foams,
It can also be used as a filler for mixing into rubber, plastics, etc. manufactured by injection molding. In addition, this slag powder can be stably obtained as a steel by-product, and has the prospect of becoming a filler for resins that is cheaper than the conventionally widely used calcium carbonate.

[0024]

As explained above, in the present invention, by treating slag powder with a substance containing polyhydroxyl groups, deterioration of the powder is suppressed and deterioration over time is prevented. Therefore, the treated powder does not undergo a curing reaction, and when mixed with an organic binder to produce a composite, for example, a product with stable quality can be obtained.

[Brief explanation of the drawing]

[Figure 1] Comparison of the change over time in the flexibility of a composite sheet made from slag powder treated with a polyhydroxyl group-containing substance with the change over time in the flexibility of a composite sheet made from untreated slag powder. graph shown

Claims (1)

[Claims] 1. A slag powder treated with a polyhydroxyl group-containing substance, which is obtained by immersing a powder obtained by pulverizing blast furnace slag or steelmaking slag in an aqueous solution of the polyhydroxyl group-containing substance and then drying the powder.