JPH05117001A - Hardened material of cement - Google Patents

Abstract

PURPOSE:To obtain a hardened material of cement having excellent mechanical strength by blending iron clay with cement and a water-absorptive polymer including water required for hardening the iron clay and the cement and compression molding the blended material. CONSTITUTION:100 pts.wt. cement (e.g. Portland cement) is blended with 5-150 pts.wt. based on dried powder of mixed powder (iron clay) consisting essentially of gypsum produced as a by-product in a plant for producing pigment of titanium dioxide with sulfuric acid method and blended with a water-absorptive polymer (e.g. PQ polymer) containing such as amount of water as to be required in hydration reaction of cement and iron clay as inclusion water. In the case, a required amount of water for hardening may be previously absorbed in the water absorbing polymer. The prepared mixture is molded into a desired shape by a vacuum degassing extruder and cured for about two weeks to give a hardened material of cement having excellent mechanical strength such as compression strength and flexural strength. The hardened material may be optionally mixed with a magnetic material, an electrically-conductive material and a ferroelectric material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an effective use of a mixture powder (abbreviated as iron clay) containing gypsum and iron oxide as main components, which are by-produced in a sulfuric acid method titanium dioxide pigment manufacturing plant. In the present invention, the iron clay is mixed with cement and a water-absorbing polymer that clathrates water in the structure, and the mixture is pressure-molded to obtain a cement hardened product. The hardened cement product of the present invention is excellent in compressive strength, bending strength, etc. as compared with general concrete and cement mortar, and thus is useful as various building materials such as outer wall materials, inner wall materials and roof materials. In addition, the hardened cement product of the present invention is widely used as a functional material such as an antistatic material, an electromagnetic wave absorbing material, a magnetic material and a ferroelectric material by blending a magnetic material, a conductive material, a ferroelectric material and the like. Is what you can do.

[0002]

2. Description of the Related Art In a sulfuric acid method titanium dioxide pigment manufacturing plant, titanium ore such as ilmenite is digested with sulfuric acid to form titanyl sulfuric acid, which is hydrolyzed to collect titanium dioxide, and a large amount of waste sulfuric acid is generated. This waste sulfuric acid is usually neutralized with an alkali such as calcium carbonate and recovered as a powder of a mixture of gypsum and iron oxide, which is called iron clay, as a main component. Although a method for effectively utilizing this iron clay has been studied in the past, the present situation is that a method for effectively utilizing a large amount of iron clay and utilizing it in a large amount has not yet been established.

[0003]

DISCLOSURE OF THE INVENTION The present inventor has conducted various studies on effective utilization of iron clay, and used iron clay in place of sand or gravel used as an aggregate in the production of concrete or cement mortar. I focused on doing and researched. In the conventional production of concrete and cement mortar, when uniformly mixing cement, aggregate and water,
It requires much more water than is necessary to hydrate the cement to maintain good flowability. Cement, iron clay, water was uniformly kneaded according to this conventional method, and cured and cured, but water other than the theoretical amount required for hydration does not affect curing and evaporates, Porosity due to air bubbles was generated, and the resulting cement hardened product had reduced mechanical strength and poor durability, making it difficult to effectively use iron clay.

[0004]

As a result of continuous research to solve the problems of the prior art, the present inventor has found that if the cement can be hardened only with a reaction theoretical amount of water necessary for its hydration reaction, mechanical strength It was found that a hardened cement product having excellent mechanical strength such as durability can be obtained. Based on this finding, a broader study was conducted to mix the water absorbing polymer in which the theoretical amount of water necessary for the hydration reaction of hemihydrate gypsum in cement and iron clay was included in the structure with the iron clay and cement. By further press-molding if necessary, the curing reaction of the gypsum component contained in the iron clay will be utilized, and the compression strength,
It was possible to obtain a cement hardened product having excellent bending strength and the like.

That is, the present invention is a hardened cement product produced by mixing a powder mixture of gypsum and iron oxide as a main component, cement and a water-absorbing polymer that clathrates water in the structure, or further by pressure molding. It is about.

[0006] A mixture powder containing gypsum and iron oxide as the main component means that titanium ore such as ilmenite is digested with sulfuric acid to produce titanyl sulfuric acid at a sulfuric acid method titanium dioxide pigment manufacturing plant, which is hydrolyzed to form titanium dioxide. It is obtained by neutralizing the collected waste sulfuric acid with an alkali such as calcium carbonate, and is abbreviated as iron clay in the present specification. In the present invention, in addition to the iron clay, any mixture powder containing gypsum and iron oxide as a main component can be used. An example of the chemical analysis value (wt%) of iron clay is shown in the following table. Normally, iron clay is 10 to 30 wt% as CaO and 15 to 35 wt% as SO ₃ .
The content of Fe ₂ O ₃ is 15 to 30% by weight.

[0007]

It has been found that iron clay is a neutral substance having a pH of about 7, is harmless when used as an aggregate of a hardened cement, and is rather preferable. It is desirable to dry the iron clay before use, and it is particularly desirable to heat or calcine at a temperature of around 150 ° C. to make the gypsum component into semi-water or anhydrous gypsum. The iron clay obtained by drying, heating or baking in this way is a powder with good fluidity,
A theoretical amount of water required for curing can be included and uniformly mixed with the water-absorbing polymer powder described below. The semi-water or anhydrous gypsum contained in the heated or calcined iron clay powder is easily solidified by the water released from the water-absorbent polymer during pressure molding, and in the hydration reaction of cement that requires time, It is effective in maintaining moldability and preventing deformation. That is, when cement is hardened and molded without mixing with iron clay, it becomes soft and easily deformed, but when iron clay is present, semi-water or anhydrous gypsum can serve as a shape-retaining agent. It turned out. In addition, a part of the iron clay can be replaced with ordinary clay such as kaolinite, halloysite, illite, attapulgite, and various smectites.

Examples of the cement used in the present invention include various types of normal / early-strength / ultra-early-strength Portland cement, and various mixed cements obtained by mixing fly ash, blast furnace slag and the like with these cements.

In the present invention, since the theoretical amount of water necessary for the hydration reaction contained in the water-absorbent polymer is used as the water for hardening the cement, a cement compact excellent in strength and durability can be obtained. Further, in the present invention, a mixture of iron clay, cement, and a water-absorbing polymer that clathrates water in the structure in an amount equal to or more than the theoretical amount necessary for hydration, and a lightweight cement molded product when not subjected to subsequent pressure molding Can be In this case, blending of the foam material is also effective.

The water-absorbent polymer used in the present invention includes natural products such as pulp and absorbent paper, hydrophilic polymers such as cross-linked polyvinyl alcohol and cross-linked polyoxyethylene,
Various kinds of super absorbent polymers such as starch type, cellulose type and synthetic polymer type can be used. Commercially available super absorbent polymers include PQ polymer (trade name, Osaka Organic Chemicals), ALASORP (trade name, Arakawa Kagaku), Wonder Gel (trade name, Kao), Sunweto (trade name, Sanyo Kasei), Sumika gel ( Product name, Sumitomo Chemical),
AQUAKEEP (trade name, iron chemistry), AQUARIC (trade name, Nippon Shokubai Chemical Co., Ltd.), dry tech (Drytech,
Product name, Dow Chemical), Water lock (Water)
Lock, trade name, grin processing, Aqualon, trade name, Hercules, Fabor, trade name, Stockhausen,
Luquasort, trade name, BAS
F) and the like, and any of them can be used. Among these, the PQ polymer is one that has been subjected to a special treatment with an inorganic substance when producing sodium polyacrylate,
Even if it absorbs 50 times the weight of water, it is in the form of a dry dry powder, which is preferable. That is, the PQ polymer is a water-absorbing polymer in which water is included in the structure and has an independent fine particle dry state even after absorbing a theoretical amount of water necessary for the hydration reaction. It can be easily mixed with the iron clay in the powder state, and the contained water can be easily released by pressure molding such as extrusion or pressing. Therefore, it is most suitable for producing a cured product. In the case of a water-absorbing polymer other than the PQ polymer, when 50 times the weight of water is absorbed, it does not become a dry and dry powdery state, and mixing becomes difficult, and it is necessary to reduce the amount of water absorption. In addition,
The particle size of the PQ polymer when water is included depends on the particle size of the PQ polymer and the amount of water absorbed, and is 0.03 to
Since it can be adjusted freely within the range of 5.0 mm,
The particle size can be appropriately selected according to the working conditions at the time of mixing with cement and iron clay.

The mixing ratio of cement and iron clay is
Iron clay is 5 to 150 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of cement on a dry powder basis. If the amount of iron clay is less than this range, the initial curability will be poor, and if it is too large, the compressive strength will be
It is not practically preferable because the tensile strength becomes weak.

The amount of the water-absorbing polymer used is at least the amount necessary to absorb the theoretical amount of water required for the hydration reaction of cement and iron clay. It should be noted that, like mere dry powder of iron clay, the gypsum component in it is 2
When using water gypsum, the water-absorbing polymer is used in an amount sufficient to absorb the amount of water required for hydration of the cement.

In the cement molded product of the present invention, when the cement, the iron clay and the water absorbing polymer are mixed, if necessary, a magnetic material, a conductive material, a ferroelectric material, etc. are blended to prevent the electrification. As a functional material such as a material, a wave absorber, a magnetic material, and a ferroelectric material, it can be widely used as a wave absorber, a clean room wall material, and a floor material. Fe ₂ is used as the magnetic material.
O ₃ , Fe ₃ O ₄ , various ferrites, Fe, Ni, C
Powders such as o and CrO ₂ and conductive materials include carbon, Cr, Ni, Fe, Al, Si, Sn and Sb-containing S
Various types of powders such as TiO ₂ coated with the nO ₂ layer, powders of various shapes, and ferroelectric materials include BaTiO ₃ and PbTi.
Examples of the powder include O ₃ and SrTiO ₃ .
A magnetic material, a conductive material, a ferroelectric material, etc. are preferably added in an amount of 0.1 to 50% by weight, preferably 5 to 30% by weight, based on cement.

[0015]

【Example】

Example 1 Iron clay produced as a by-product from a sulfuric acid method titanium dioxide manufacturing plant was calcined at 150 ° C. for 30 minutes to obtain a mixture powder containing gypsum, iron oxide and titanium dioxide as main components (19.8 wt% as CaO, SO ₃ 21.6% by weight, Fe
₂ O ₃ is 22.5% by weight and TiO ₂ is 15.8.
(Wt% content). On the other hand, as a super absorbent polymer,
Using PQ polymer BL100 (trade name, sodium polyacrylate type, manufactured by Osaka Organic Chemistry), a theoretical amount of water necessary for hardening cement and iron clay is added in advance, stirred and mixed to make water the structure of PQ polymer. It was enclosed in the inside to obtain a dry powder. The amount of water added at this time was about 50 times the weight of the PQ polymer. The above-mentioned mixture powder containing gypsum and iron oxide as main components and PQ polymer powder in which water was included in the structure were mixed with cement at the ratio (weight ratio) shown below. This mixing could be easily and uniformly done. Cement: Iron clay: Water-containing PQ polymer = 100: 20: 20.4 (water: PQ polymer = 20:
0.4) The obtained mixture was vacuum degassed by an extruder to obtain a length of 300 mm,
After being formed into a plate shape having a width of 50 mm and a thickness of 10 mm, it was cured at room temperature at 20 ° C. for 14 days. The molded plate thus obtained has a compressive strength of 510 Kg / cm ² and a bending strength of 162.
It was Kg / cm ² and was superior to ordinary cement mortar board.

Example 2 A mixture was obtained in the same manner as in Example 1 except that the mixing ratio of each component was as follows. Cement: Iron clay: Water-containing PQ polymer = 100: 40: 23 (water: PQ polymer = 22.5:
0.5) This mixture was put into a press, a pressure of 120 Kg / cm ² was applied to form a column having a diameter of 30 mm and a height of 30 mm, and then the mixture was cured at room temperature at 20 ° C. for 14 days. The compression strength of the thus obtained molded product was 450 Kg / cm ² .

Example 3 Pois (trade name, manufactured by Kao Corporation) was used as the superabsorbent polymer in the above Example 1, and a mixture was obtained in the following mixing ratio of each component. In this case, in order to make the water-containing poise powdery, increase the amount of poise to about 1
Three times the weight of water was added. Cement: Iron clay: Water-containing poise = 100: 30: 23 (water: poise = 21.4: 1.
6) The obtained mixture is vacuum degassed by an extruder to obtain a length of 300 mm,
After being formed into a plate shape having a width of 50 mm and a thickness of 10 mm, it was cured at room temperature at 20 ° C. for 14 days. The molded plate thus obtained has a compressive strength of 470 Kg / cm ² and a bending strength of 118.
It was Kg / cm ² .

Example 4 A molded product was obtained in the same manner as in Example 2, except that the components were mixed in the following proportions. Cement: Iron clay: Water-containing PQ polymer = 100: 100: 28.5 (water: PQ polymer = 2
7.9: 0.6) The compression strength of the obtained molded body was 390 Kg / cm ² .

Example 5 In Example 1, cement, iron clay and PQ were used.
Further added γ-Fe ₂ O ₃ powder in the polymer, was obtained a molded plate was treated in the same manner except that mixing in the following proportions. Cement: Iron clay: γ-Fe ₂ O ₃ : Water-containing PQ
Polymer = 100: 10: 10: 20.4 (water: PQ polymer =
20: 0.4) The obtained molded plate had a compression strength of 490 Kg / cm ² , a bending strength of 148 Kg / cm ² , and a coercive force of 450 Oe.

Example 6 A molded plate was obtained in the same manner as in Example 5 except that cobalt-treated γ-Fe ₂ O ₃ was used in place of the γ-Fe ₂ O ₃ powder. The compression strength of the obtained molded plate is 48.
5 kg / cm ^2, bending strength 140 kg / cm ^2, the coercive force was 690Oe.

Example 7 In Example 5, acicular Ti coated with an Sb-containing SnO ₂ layer as a conductive filler instead of the γ-Fe ₂ O ₃ powder.
Using O ₂ (FT-1000, trade name, Ishihara Sangyo),
A molded plate was obtained in the same manner except that the mixing was carried out in the following proportions. Cement: Iron clay: FT-1000: Water-containing PQ
Polymer = 100: 10: 20: 20.4 (water: PQ polymer =
20: 0.4) The obtained molded plate has a compressive strength of 445 Kg / cm ² , a bending strength of 110 Kg / cm ² , and a resistivity of 0.15 ohm.
It was cm.

[0022]

According to the present invention, the following effects are brought about. (1) Gypsum such as iron clay, which is a large amount of by-product, and a mixture powder containing iron oxide as a main component can be effectively used. (2) By adding a mixture powder containing a gypsum component such as iron clay to cement, the gypsum component can be used as an early solidifying agent, so that when only cement is used, it is soft and easily hardened The drawback of the body creating can be eliminated. (3) By using clathrate water contained in the water-absorbent polymer, it is possible to cure with only the theoretical amount of water required for hydration. Therefore, a hardened cement product having mechanical strength superior to that of conventional cement mortar and concrete products can be obtained. (4) A mixture obtained by adding 10 to 50 times by weight of water to the water-absorbent polymer can be mixed in the form of free-flowing powder with cement or other additive powder in the form of powder. Further, since only the theoretical amount of water necessary for curing can be used, a product having high strength can be obtained. (5) By blending a magnetic material, a conductive material, a ferroelectric material, or the like, as a functional material such as an antistatic material, an electromagnetic wave absorbing material, a magnetic material, or a ferroelectric material, for example, an electromagnetic wave absorbing molded body or a clean room. It can be widely used as a wall material and flooring material.

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Claims (2)

[Claims] 1. A hardened cement product, which is produced by mixing a mixture powder containing gypsum and iron oxide as main components, cement and a water-absorbing polymer that clathrates water in the structure, or further by pressure molding. 2. A mixture powder of gypsum and iron oxide as a main component, cement, a water-absorbing polymer for clathrating water in the structure, and at least one of a magnetic material, a conductive material and a ferroelectric material, or further mixed. A hardened cement product produced by pressure molding.