JPS5913462B2 - Type 2 anhydrous gypsum hardening material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is based on Patent Application No. 143771 (Japanese Unexamined Patent Publication No. 71654) filed in 1973 by the inventor of this application. Involved in the improvement of inventions for materials.

Conventionally, there have been hardening compositions based on gypsum, steel furnace plugs, and cement, and it is known that a hardening composition can be easily obtained by blending these three materials.

The blending composition in this case refers to gypsum (dihydrate gypsum).

) 10-15 weight percent cement, 2-5 weight percent steel death slag, 85-90 weight percent, or about 10 weight percent gypsum (gypsum dihydrate), 30-50 weight percent cement, 40-6 steel furnace slag.
Gypsum (dihydrate gypsum) with a composition of about 0 weight percent
No cured compositions with more than 30 weight percent IP loading were observed.

This is because it has generally been confirmed that when 30% by weight of gypsum (gypsum dihydrate) is blended, the physical properties of the cured product deteriorate.

In addition, the gypsum that has been used in the past is dihydrate gypsum, and it is rare to see quasi-pyrochlore gypsum used as a compounding material.

① Semi-pyrophoric gypsum shown in this invention is a by-product during the production of hydrofluoric acid, and is usually only used as a raw material for expanded cement, and conversion to trihydrate gypsum is currently not considered due to cost considerations.

■ Quasi-pyrolyte gypsum has similar properties to α-gypsum, so depending on the application method, it can be expected to be made into a fairly unique practical material, but it has a slow curing speed and hydrofluoric acid In the case of by-products, there is a quality problem because they contain impurities during manufacturing, and although they are inexpensive materials, their uses are limited.Also, even if the quality could be improved to be close to pure products, they would be fatal as plaster. The problem of weak water resistance, which is a typical characteristic, remains.

The present invention solves these problems (especially hardening speed and water resistance), and as a result of repeated improvement studies aimed at utilizing the advantages of quasi-pyrolyte gypsum as is, the following methods are used to solve these problems: In other words, a curing accelerator was mixed with the crushed quasi-pyrolyte gypsum, and slaked lime and water were added to adjust the pH to 11.
-12 slare IJ- can be cured in a relatively short time, although it varies depending on the size of the crushed particles of anhydrous gypsum.

The strength of this cured product is relatively high, comparable to that of alpha gypsum, but the water resistance is extremely poor, comparable to the results shown in the case of trihydrate gypsum units.

Therefore, with the aim of improving this point, we further investigated the effects of various silicate substances that differed from the mechanism of the earlier-filed invention. In order to meet the purpose, we thought that it would be more reasonable to use artificial materials than natural materials, and from these materials, we mainly selected iron and steel furnace slag materials for experiments.

A steel furnace flag is displayed for substances that correspond to steel furnace plug-related substances.
It can be used for silica for fertilizer, blast furnace slag cement, etc.

Among these, blast furnace slag cement was considered to be the most suitable material in terms of availability, quality reliability, physical properties, and economic efficiency, so this was selected as the representative material.

The experimental results show that in the case of by-product quasi-scorched gypsum, there are no conclusive results from various measurements regarding the physical properties of the hardened material obtained by adding blast furnace plug cement in the range of 8.5 to 24% by weight. A clue to improvement was finally obtained by adding about a weight percent.

In other words, the cured product obtained by blending with a coulometric content of 24% or less is first of all non-luminous in both strength and curing speed;
It was confirmed that the strength was finally improved when the content was about 50% by weight, and the strength in both bending and compression was nearly 200% compared to the additive-free material.

However, the curing speed was still slow, and in all cases it took more than three times as long as the additive-free material, which was found to be a practical problem.

Furthermore, although the water resistance was generally improved, it was still in the unsatisfactory range.

Therefore, in order to improve these various points, as a result of further consideration,
The addition of ordinary Portland cement is effective for the lack of strength that occurs when the content is less than 24 coulometric percent, and the addition of alumina cement of 2 to 4 percent by weight is generally effective for improving the acceleration of curing speed required. It turns out that there is.

In addition, the water resistance could be improved by the synergistic effect of both ordinary porland cement and alumina cement.

By appropriately combining these results, the three points of strength, curing speed, and water resistance can be solved at the same time.

Furthermore, as expected, the curing speed was slow and the strength of the cured product was slightly lower under conditions in which no curing accelerator was added.

Examples of similar materials for the steel furnace plug material used here include the above-mentioned blast furnace plug cement, steel furnace nug (quenched product, slowly cooled product), and converter plug.

Furthermore, since it is a reaction between solids that involves dissolution, the first requirement is that the particle size of each raw material to be charged is as finely pulverized as possible, usually 170 mesh or less, preferably 200 mesh or less. The results showed that it is desirable that

Next, if we show the appropriate blending range of each raw material, ■
Geothermal water gypsum has a content of 30 to 70% by weight (38 to 88.6% by weight as dihydrate gypsum), and if it exceeds 70% by weight, water resistance deteriorates and there is a problem in practical use.

Although water resistance is still not perfect in the range of 47 to 70 weight percent, it is sufficient for use as a building material, especially as an interior material.

At 30-47% by weight, the physical properties show strength and water resistance suitable for building materials and civil engineering materials, but from an economic point of view mainly considering the effective use of geothermal water gypsum, it is around 45% by weight. Can be seen.

Furthermore, if the coulometric content is less than 30 percent, it becomes difficult to call it a geothermal water gypsum hardening material.

■If we consider blast furnace plug cement as a steel furnace flag substance corresponding to geothermal water gypsum, the appropriate range is 5.
Approximately 5 to 20 weight percent.

If it is more than 55% by weight, it is difficult to think of it as a geothermal water gypsum hardening material, and if it is 55 to 45% by weight, there is no problem with both strength and water resistance, and the material is considered to be practical in all directions. .

A content of 45 to 20% by weight is sufficient as an interior building material, while a content of less than 20% by weight results in poor water resistance and is a practical problem.

The limit for improving the physical properties of ordinary Portland cement is about 15% by weight, and no effect on the physical properties was observed even if the increase was more than this.

On the other hand, the appropriate range for alumina cement is 1.5~
It is considered that 5% by weight is added, and if it is less than 1.5% by weight, the curing rate is not as noticeable compared to a product without additives.
It was found that when the content exceeds 5% by weight, the water condensation reaction rapidly progresses and the temperature of the cured product increases, and as a result, the strength actually decreases.

(2) The main purpose of adding slaked lime to geothermal water gypsum is to neutralize it, so about 0.5 to 1.0 weight percent is sufficient.Additional additions other than necessary increased the amount of mixed water and decreased strength.

The amount of water use accelerator added is 1 for the total amount of potassium sulfate and potassium alum.
It is desirable to add a small amount of geothermal water at about 1.5% by weight, considering the fact that it is an insoluble component and economic efficiency.

Of course, in terms of the economical composition of the hardening material from a practical point of view, the maximum amount of quasi-pyrophoric gypsum should be added within the range that maintains the highest physical properties of the hardening material.

The economic composition of this hardening material can be summarized as follows.

■40-45% by weight of quasi-scorched gypsum, 40-45% by weight of blast furnace slag cement, 6-13% by weight of ordinary Portland cement, 2-5% by weight of alumina cement, 0.5% by weight of slaked lime, sulfuric acid power IJ 0.6 Weight percent, potash alum 0.
At about 4% by weight, in short, after this composition, a composition in which there is a large amount of quasi-pyrophoric gypsum gradually decreases the physical properties, and conversely, a composition in which there is a small amount of quasi-pyrophoric gypsum is optimal. The physical properties will be maintained.

Examining the water utilization reaction of the hardening material of this invention, it is found that anhydrous gypsum is dissolved by the action of potassium sulfate and potassium alum, which are water utilization promoters, and C3 in steel furnace flag substances and cement is dissolved.
As a result of the three-way reaction with A and lime in the system, ettringite (3CaO-A40s) is rapidly formed through a pozzolanic reaction.
・3CasO4@32H20), etc., which hardens and improves physical properties such as strength and water resistance of the hardened product.

It has been determined that the reaction rate in this case is further accelerated by the addition of alumina cement, and this invention constitutes an atmosphere for optimal production of IJn gite.

Therefore, the absence of hydration accelerator or alumina cement results in a time delay in completion of cure.

These relationships were also supported by the results of X-ray analysis.

As shown in the examples, a curing agent blended with an appropriate composition was cured in 5 to 6 hours by stirring a slurry with water in an amount of about 30 to 33 weight percent.

When this cured product is cured for 7 days at room temperature under saturated steam, the specific gravity is 1.8 to 2.0, and the compressive strength is 350 to 400.
kg/CIIL, bolting strength 80-90kg/CTL,
The water resistance of the constant mass dried at 45°C is maintained in running water at room temperature for 20 days (
The weight loss was only 0.2 to 0.9 percent by weight when water was passed through at room temperature at a rate of 201 times per unit surface area (d) of the 2 cm cubic molded body.

Examples (See Figure 1) For semi-scorched gypsum, which is a by-product of hydrofluoric acid production, 32-mesh sieve undersize (coarse particles) or 200-mesh sieve undersize (fine particles) were used.

100 parts of this 32 mesh sander type anhydrous gypsum and blast furnace slag cement type 0 9,6 as a steel furnace flag material.
100 parts of 200 mesh anhydrous gypsum and 32.5 to 101.6 parts of type 0 blast furnace slag cement mixed with 1 part of slaked lime.
．． 1 to 2.3 parts were further mixed.

Add 1.4 to 1.6 parts of ground potassium sulfate and 1 part of potassium alum to the collected water so that the amount of water mixed with the total amount is 30 parts.
．． After dissolving 0 parts, the mixture was further mixed with the anhydrous gypsum-blast furnace slag cement mixture and thoroughly stirred, and then poured into a gunmetal mold while applying a pie break and hardened.

When the fluidity of the slurry was insufficient, a small amount of water was appropriately added to maintain fluidity.

This is called Experiment A.

1.0 to 1.2 parts of slaked lime to a mixture of 100 parts of 200 Meshunda 1 type anhydrous gypsum, 32.5 to 102.2 parts of Class 0 blast furnace plug cement, and 8.7 to 27.7 parts of ordinary Portland cement. Further mixing was performed.

After dissolving 1.3 to 1.5 parts of crushed potassium sulfate and 0.9 to 1.0 parts of potassium alum in the collected water so that the amount of water mixed is 30 parts to the total amount of preparation, Gypsum and blast furnace flag cement - further mixed with ordinary Portland cement mixture, thoroughly stirred, and then pie-broken into gunmetal molds.
It was poured and hardened while being applied with water.

When the fluidity of the slurry was insufficient, a small amount of water was appropriately added to maintain fluidity.

This is called Experiment B.

32 mesh under or 200 mesh under 1 type anhydrous gypsum (100 parts) and blast furnace slag cement) Class C 32.5
~101.9 parts and alumina cement No. 1 3.1~7,
1.1 to 1.3 parts of slaked lime was further mixed into the mixture of 4 parts.

Add 1.4 to 1.5 parts of ground potassium sulfate and 0 parts of potassium alum to the collected water so that the amount of water mixed is 30% of the total amount of water.
．． After dissolving 8 to 1.0 parts, the mixture was further mixed with the anhydrous gypsum-blast furnace slag cement-alumina cement mixture, stirred with light, and then poured into a gunmetal mold while being exposed to a vibrator and hardened.

When the fluidity of the slurry was insufficient, a small amount of water was appropriately added to maintain fluidity.

Let this experiment be C.

A mixture of 32.6 to 159.7 parts of blast furnace slag cement type 0, 8.7 to 41.3 parts of ordinary portland cement, and 3.0 to 95 parts of alumina cement No. 1 to 100 parts of 200 mesh 1 type anhydrous gypsum. Add slaked lime to 1.
0 to 1.6 parts were further mixed.

1.4 to 1.6 parts of ground potassium sulfate and 0 parts of potassium alum are added to the water collected so that the amount of water mixed is 30% of the total amount of water.
．． After dissolving 9 to 1.0 parts, the mixture was further mixed with the anhydrous gypsum-blast furnace flag cement-ordinary Portland cement-alumina cement mixture, thoroughly stirred, and then poured into a gunmetal mold while applying a vibrator to harden. I let it happen.

When the fluidity of the slurry was insufficient, this experiment was designated as D in which a small amount of water was appropriately added to maintain fluidity.

1.2 parts of slaked lime was further mixed into a mixture of 100 parts of 200 Metsuyuanda 1 type anhydrous gypsum, 101.7 parts of blast furnace plug cement type 0, 27.6 parts of ordinary Portland cement, and 7.6 parts of alumina cement No. 1. .

Mix the sampled water with the anhydrous gypsum, blast furnace flag cement, ordinary Portland cement, and alumina cement mixture so that the amount of mixed water is 30% of the total amount of water mixed, and after stirring thoroughly, pie break into a gunmetal mold. It was poured and cured while applying -.

When the fluidity of the slurry was insufficient, a small amount of water was appropriately added to maintain fluidity.

Let this experiment be E.

The results of a subsequent investigation of the curing time (time until demolding), strength, and water resistance of the cured product obtained in the above experiment are also shown in FIG.

The strength was measured using a Shimadzu universal testing machine, and the test piece for measuring compressive strength was 2c1rL x 2cIrL x 2cI.
5 rL cubes, 2cIIl x 2C for bending strength measurement
Three rectangular parallelepipeds of rrL x 6crIL were used, the strength was the average value of these, and the age was 7 days at room temperature and saturated steam pressure.

Water resistance test specimen is 2c11'L x 2CII'L x 2CrrL
Two cubes were used, and tap water of 5# in the 5-day test and 21 in the 200-day test was poured per unit surface area (d).

The weight loss was determined based on the average value of two samples, which were left at room temperature for one day after drying at 45° C. to constant weight.

Weight loss measurement wave compressive strength was measured.

In addition, various surface conditions were observed on the test specimens.

Experiments 19 and 20 were conducted using granulated silica blast furnace slag for fertilizer as the steel furnace flag material and were confirmed under the optimum experimental conditions described above.

Experiments 21 and 22 compared two types of commercially available products from Company A under the same conditions as the present experiment.

Next, in Experiment 23.24 as a comparative example, 30 mesh under or 200 mesh under ■ semi-scorched gypsum was added to a solution in which a hardening accelerator was dissolved in collected water so that the water content was 30%. After mixing and stirring thoroughly, slaked lime was added little by little to adjust the pH of the mixed slurry to 11-12, and then poured into a mold and hardened.

The amount of slaked lime added is 1.6 to 1 per 100 parts of anhydrous gypsum.
．． The amount of potassium sulfate was 1.6 parts, and the amount of potassium sulfate was 1.0 parts.

The physical properties of the cured product were investigated in the same manner as before.

As seen in Table 1, the cured product obtained by the formulation as in this example has improved strength and water resistance compared to the cured product obtained in the comparative example, and the curing time is also greatly reduced. It can be shortened and is extremely suitable as a building material and soil improvement material.

[Brief explanation of the drawing]

Figure 1 shows experimental values.

Claims (1)

[Claims] 1 ■ 30-70% quasi-pyrolyte gypsum, 55-20% steel furnace plug material, and 0-15% ordinary Portland cement.
%, alumina cement 1.5 to 5%, slaked lime 05 to 0.7%, and anhydrous gypsum hydration accelerator slightly %. Water-gypsum hardening material.