KR20200001255A - Geopolymer block composition using molten slag and method for manufacturing the same - Google Patents

Abstract

Provided is a method for preparing a geopolymer block, which comprises: mixing molten slag and a foaming agent to produce a geopolymer raw material; adding a complex activator mixed solution to the geopolymer raw material to produce a geopolymer paste; and molding the geopolymer paste to produce a geopolymer molded body. The step of producing the geopolymer molded body comprises the following steps: filling 40-70% of a mold frame by volume with the geopolymer paste; and releasing gas produced in the geopolymer paste filled in the mold frame through an opening formed in the mold frame.

Description

GEOPOLYMER BLOCK COMPOSITION USING MOLTEN SLAG AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a geopolymer block composition and a method of manufacturing the same, and more particularly, by using molten slag generated during the operation of coal gas combined cycle (IGCC), superior compressive strength, thermal insulation, and light weight than ALC blocks. It relates to a lightweight geopolymer block composition having and a method for producing the same.

 Integrated Gasification Combined Cycle (IGCC) uses environmentally friendly coal, but has higher generation efficiency than coal-fired power plants and emits pollutants in the exhaust gas after high efficiency. It is a power generation technology that can be minimized. In Korea, 300 MW-class power generation facilities have been installed and are in operation. Currently, discussions are underway to build the IGCC Unit 2, and IGCC facilities will continue to be built as part of the replacement of existing thermal power plants in order to solve the environmental pollution problem. It is expected to come true. In the operation process of the IGCC plant, the coal gasification reaction is operated under high temperature / high pressure conditions, so that ash and metals contained in coal used as raw materials are melted and discharged into slag. Currently, in Korea, since there is no technology for processing molten slag generated during the operation of a coal gas combined cycle power generation facility, all of it is landfilled. Therefore, since landfills are required for waste disposal, there is a need for technology for recycling landfills and environmental pollution problems.

On the other hand, ALC blocks, which are currently sold as building materials, are manufactured using inorganic materials, so they have fire resistance that does not burn, and because they have about 70% of pores formed inside, they have excellent insulation performance and 0.25 weight than ordinary concrete. It is about twice as low. The raw materials and manufacturing methods used are siliceous materials such as silica or silica sand and quicklime, cement, anhydrous gypsum and blowing agent as raw materials.They are supplied at a rate and then poured, pre-cured, cut and autoclave. Manufactured in the order of curing process. At this time, the autoclave curing process, which is one of the manufacturing processes, is a high temperature and high pressure steam curing method that is performed at 180 ° C. and 10 atm for 10 to 12 hours. In this process, since a high temperature / high pressure reactor is used, the size of the product is limited depending on the size of the facility, the operating cost is high, and the cost of the product is expensive because much attention is required for the operation of the facility.

The present invention manufactures a geopolymer paste using waste molten slag and blast furnace slag similar in composition to coal gasification molten slag, and then provides a non-combustible insulating material having a compressive strength of at least a certain level while having a thermal insulation function. It is intended to provide a method of preparation.

In addition, the present invention is to provide a method of manufacturing a building material that can reduce the production cost and replace the cement as the operating pressure is normal pressure during the manufacturing process and the drying operation temperature is 70 ~ 90 ℃ low.

In order to solve the above problems, an embodiment of the present invention comprises the steps of mixing the molten slag and blowing agent to produce a geopolymer raw material; Adding a complex activator mixed solution to the geopolymer raw material to produce a geopolymer paste; And molding the geopolymer paste to produce a geopolymer molded article, wherein the producing of the geopolymer molded article comprises: filling the geopolymer paste by 40 to 70% of a volume of a mold; And discharging the gas generated from the geopolymer paste filled in the mold through the opening formed in the mold.

The blowing agent preferably contains 0.10 to 0.50 wt% based on the geopolymer raw material.

The blowing agent preferably comprises waste silicon sludge powder.

The complex activator mixed solution preferably has a weight ratio of alkali activator to water glass of 1: 1.

The step of producing the geopolymer paste, preferably further comprises the step of kneading evenly after supplying the water to the water content / solid weight ratio in the liquid sample to 20 to 30% by weight to the geopolymer paste.

Preferably, the step of pulverizing the molten slag to 80 ~ 120 ㎛ before the step of producing the geopolymer raw material.

The producing of the geopolymer molded body may include: drying the mold filled with the geopolymer paste at a high temperature for 24 hours in a dryer operated at 70 to 90 ° C .; And it is preferable to further comprise the step of room temperature curing for 3 days at room temperature conditions the high temperature dried mold.

Another embodiment of the present invention provides a geopolymer block composition produced by the method of preparing the geopolymer block composition.

It is preferred to include Hydroxycancrinite (Na ₈ Al ₆ Si ₆ O ₂₄ (OH, CO ₃ ) ₂ .2H ₂ O).

Another embodiment of the present invention provides a geopolymer block comprising a geopolymer block composition.

According to the method for producing a geopolymer block composition according to the present invention, IGCC molten slag, waste molten slag, and blast furnace slag, which should be discharged from the IGCC plant and disposed of, can be used as raw materials for construction materials. It works.

In addition, it is possible to replace the cement currently used as a raw material for ALC block manufacturing, and to use waste in the production of products, thereby reducing environmental protection and cost.

In addition, the conventional ALC process requires a high temperature (180 ° C.) / High pressure (10 bar) reaction operation, but in the present invention, since the operating pressure is normal pressure and the drying operation temperature is low as 70 to 90 ° C., the product production cost can be reduced. have.

In addition, the heating and drying process can be performed simultaneously with the molding to shorten the manufacturing time and to control the shape of the molding.

1 is a flowchart illustrating a method of manufacturing a geopolymer block using molten slag according to an embodiment of the present invention.
2 (a) or 2 (b) shows the results of X-ray diffraction (XRD) and XRF analysis of the molten slag according to an embodiment of the present invention.
Figure 3 is a picture of the mold according to an embodiment of the present invention.
Figure 4 is a picture of the molded body molded in the mold according to an embodiment of the present invention.
5 is a pore distribution shape photograph of a geopolymer molded article prepared according to an embodiment of the present invention.
6 shows the compressive strength measurement results according to the filling amount of the geopolymer paste according to an embodiment of the present invention.
Figure 7 shows the specific gravity measurement results according to the filling amount of the geopolymer paste according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Terms and words used herein are terms selected in consideration of functions in the embodiments, and the meaning of the terms may vary according to the intention or custom of the invention. Therefore, the terminology used in the embodiments to be described later, according to the definition when specifically defined in the present specification, if there is no specific definition should be interpreted as meaning generally recognized by those skilled in the art.

1 is a flowchart illustrating a method of manufacturing a geopolymer block using molten slag according to an embodiment of the present invention, and FIG. 2 (a) or 2 (b) shows an XRD (of molten slag) according to an embodiment of the present invention. X-ray Diffraction) and XRF analysis results are shown, Figure 3 is a molding picture according to an embodiment of the present invention, Figure 4 is a molding picture formed in a molding die according to an embodiment of the present invention, Figure 5 is a pore distribution shape photograph of the geopolymer molded article prepared according to an embodiment of the present invention, Figure 6 shows the compressive strength measurement results according to the filling amount of the geopolymer paste according to an embodiment of the present invention, Figure 7 Shows the specific gravity measurement results according to the filling amount of the geopolymer paste according to an embodiment of the present invention.

Referring to FIG. 1, in order to manufacture a geopolymer block using molten slag according to an embodiment of the present invention, the molten slag is first washed and dried. The molten slag refers to a rock component remaining after iron is separated from iron ore, which is a raw material of iron in a steel manufacturing process. For example, when molten iron ore, coke, limestone, etc. are melted in a blast furnace (blast furnace), It may refer to that generated by melting the mineral component together. For example, the molten slag may refer to discharged from coal gasification combined cycle power generation. Most coal ashes, including fly ash from coal-fired power plants, are crystalline, but the molten slag from coal gasification combined cycle is amorphous. As shown in FIG. 2, the molten slag discharged from the coal gasification combined cycle power generation is composed mainly of silica (SiO ₂ ) and alumina (Al ₂ O ₃ ), and sodium oxide (Na ₂ O) and calcium oxide (CaO). Iron oxide (Fe ₂ O ₃ ), magnesium oxide (MgO) and the like may be included in a small amount.

On the other hand, the geopolymer (Geopolymer) has a characteristic that a chemical reaction occurs when the alkali activator such as NaOH or KOH is mixed with minerals Al-Si is the main component, the Si-O-Al-O bond as a polymer, alkali Since the physical properties and material properties of the binder are different according to the activator concentration, the additive mixture, and the manufacturing process, proper control of the binder enables the production of a product having a desired use and function. In the case of the molten slag, the main components are Si and Al. Therefore, the geopolymer paste can be manufactured by mixing Si and Al with an alkali activator in the molten slag.

Therefore, the present invention is to produce a lightweight geopolymer block having superior compressive strength, heat insulation, and light weight than the ALC block by the manufacturing method described below by utilizing the molten amorphous slag discharged from the coal gasification combined cycle.

After washing the molten slag with washing water, a drying process (S100) is performed so that the moisture in the molten slag is within 10%. At this time, when the moisture content in the molten slag exceeds 10%, the molding properties are lowered, and it may be difficult to control the ratio of the geopolymer raw material and the mixed activator mixed solution in the step of generating the geopolymer block described later.

The grinding process (S200) may be performed on the molten slag in which the drying process is performed. Since the initial shape of the molten slag sample is non-uniform, it may be difficult to uniformly mix with the complex activator mixed solution in the step of producing the geopolymer paste. Therefore, in order to improve the reactivity with the complex activator mixed solution and to easily control the component ratio of the geopolymer raw material and the complex activator mixed solution in the geopolymer paste generation step described later, the average particle size of the molten slag is 80 It may be ground to a range of ˜120 μm. If the average diameter of the molten slag is less than 80 ㎛ then it may be difficult to knead the molten slag, if more than 120 ㎛ may be difficult to uniformly mixed with the composite activator mixed solution in the step of producing a geopolymer paste, Reduced geopolymer reaction rate and poor compressive strength of the final composition.

Next, a geopolymer raw material may be produced by mixing a blowing agent in the molten slag in the form of fine particles, which are pulverized (S300). The blowing agent is for improving the porous formation of the geopolymer, and may include, for example, waste silicon sludge (Si-sludge) powder. The waste silicon sludge is generated in the process of cutting or polishing silicon in the form of wafers in various silicon industries, and the waste silicon sludge is used as a foaming agent because it generates more than 21,000 tons per year and requires recycling technology of these sludges. Waste recycling effects can be expected. On the other hand, the waste silicon sludge may be applied to a silica containing little impurities containing only a small amount of alumina.

The geopolymer block to be manufactured according to the manufacturing method of the present invention needs to be controlled so that the compressive strength, thermal insulation performance and specific gravity required in the ALC block are maintained at a certain level while maintaining a small and uniform pore shape by the blowing agent. That is, to manufacture a lightweight geopolymer block having a certain level of compressive strength and insulation performance, pores should be evenly distributed. If the pore distribution is uneven, the compressive strength of the block is reduced or the insulation is not evenly made, which makes it impossible to uniformize the product quality. Therefore, pore shape control inside the geopolymer block is very important.

Internal pore formation using a blowing agent in the geopolymer block manufacturing process is due to the generation of hydrogen gas by a chemical reaction, as shown in the following formula (1), the hydrogen is produced continuously for about 40 minutes after the production of the geopolymer paste. The waste silicon sludge blowing agent may produce a geopolymer block having a multi-pore by generating hydrogen gas through a reaction shown in the following Chemical Formula 1.

[Formula 1]

Si + ₂ NaOH + H ₂ O → Na ₂ SiO ₃ + 2H ₂

That is, since the hydrogen gas is generated by the reaction of the Si component used as the blowing agent with NaOH, pores are generated, when the blowing agent is contained in a predetermined amount or more, the mechanical strength of the geopolymer is lowered and the durability of the geopolymer composition is poor. have. Therefore, the blowing agent may be included in 0.10 to 0.50% by weight based on the geopolymer raw material.

Thereafter, a complex activator mixed solution may be added to the geopolymer raw material to generate a geopolymer paste (S400). The complex activator mixed solution may induce a geopolymer formation reaction using molten slag generated during the operation of coal gasification combined cycle (IGCC).

In the polymerization process of geopolymer, chemical reaction of Al-Si mineral occurs in high alkali state, and thus Si-O-Al-O bond, which is a polymer, is formed, and physical properties and material properties of the binder are different depending on alkali activator concentration and manufacturing process. Can vary. In order to manufacture the geopolymer block by applying such geopolymer reaction characteristics, it is necessary to supply an appropriate amount of alkali activator, supply of additives for improving the treatment performance, and control of solids and moisture ratio to have optimum molding conditions.

In this case, the complex activator mixed solution may include an alkali activator and a silicon compound. Since molten slag produced during the operation of coal gasification combined cycle (IGCC) cannot undergo a geopolymer reaction on its own, the reaction is carried out by breaking the glass film and eluting Si ^{4 +} and Al ^{3 +} ions involved in the geopolymer reaction. uses a strong alkaline activator, which can cause, OH ^- is higher the concentration of the decomposed ₂ -Al ₂ O ₃ glass bonded quickly SiO and produce large quantities of a reactive ion. Therefore, when the alkali ion concentration is high, the alkali activator may promote the decomposition of the reactant of the molten slag to produce a geopolymer having a high strength, and as a result, it is possible to improve the durability of the produced geopolymer composition.

The alkali activator is not particularly limited as long as it is a water-soluble alkali hydroxide which reacts with the molten slag (pozzolanic reaction) to produce components such as silicate and aluminate having hydraulic properties. For example, an alkali activator solution having a concentration of 10-15 M may be used as a solution in which sodium hydroxide (NaOH) is mixed with distilled water. The alkali activator solution may be prepared by mixing sodium hydroxide in a suitable concentration in distilled water at room temperature.

The silicon compound may be silicon supplied from the mixed activator mixed solution to the geopolymer raw material, and may include hydrides, oxides, siloxanes, siloxanes, halides, borides, carbides, nitrides, metal oxides, and the like containing silicon elements. It may include.

For example, the silicon compound may include water glass (Sodium Silicate, Na ₂ SiO ₃ ). The water glass enables additional Si supply in addition to Si eluted from the geopolymer raw material, such as the reaction shown in Formula 2 below. Therefore, the addition of the water glass can be controlled so as not to significantly reduce the workability while improving the compressive strength of the geopolymer block. In addition, the water glass may increase the alkalinity due to the increase of the OH- group due to the hydrolysis reaction of the water glass to further improve the dissolution of Si ^{4 +} , Al ^{3 +} ions, thereby improving the durability of the manufactured geopolymer block. have.

[Formula 2]

Na ₂ O · nSiO ₂ + (2n + 1) H ₂ O → 2NaOH + nSi (OH) ₄

In this case, the composite activator mixture solution is preferably a weight ratio of the alkali activator to water glass of 1: 1. As the water glass content increases, the compressive strength of the manufactured geopolymer composition may be improved. However, when the water glass content exceeds 75% by weight, workability is deteriorated. Therefore, the geopolymer molded body may not be smoothly manufactured. May occur. In addition, when the water glass content is too high, the crystallinity of the prepared geopolymer paste may be lowered, resulting in poor durability of the prepared geopolymer composition.

In the step of producing the geopolymer paste, by controlling the water content / solid weight ratio in the liquid sample of the geopolymer paste to increase the reaction ions can improve the reaction efficiency and improve the moldability. That is, when the alkali activator and the water glass are mixed with the geopolymer raw material, the weight ratio of the water content (liquid phase) / geopolymer raw material (solid phase) in the composite activator mixed solution is evenly supplied by supplying water such that the weight ratio is 20 to 30% by weight. You can mix or knead it. When the liquid / solid weight ratio is less than 20% by weight, the fluidity of the geopolymer paste is lowered in the step of producing the geopolymer molded body so that it is not evenly distributed in the mold, and when the excess reaction liquid is more than 30% by weight, the filter medium It can be discharged to the outside of the mold by passing through.

Next, in order to perform the geopolymer molded product generation step (S500), after controlling the liquid / solid weight ratio of the geopolymer paste and performing a kneading process, it is filled in a mold. Since the geopolymer paste is swollen during gas generation by the blowing agent, the geopolymer paste is filled with about 40 to 70% of the mold volume. At this time, in order to evenly distribute the hydrogen gas generated by the foam and to prevent the formation of large pores or irregular pores by gas retention and drift, the mold should be configured to discharge the gas evenly. In other words, the mold should be configured to form a hydrogen gas outlet in the mold for the purpose of uniform pore shape of the hydrogen gas generated by the blowing agent inside the geopolymer block.

That is, as shown in Figure 3, the molding die 10 may be a variety of forms according to the building material use, for example, in the form of a hexahedron, a plurality of openings 12 are formed in each surface 11 of the hexahedron The gas discharged from the geopolymer block can be evenly distributed and discharged in the six directions (up / down, left / right, front / back). Each hexahedral inner wall of the mold 10 is provided with a cover of fibrous material, for example, a nonwoven fabric 13, so that the swelling geopolymer paste can be compacted without leaking. The nonwoven fabric 13 may be used as a one-time and removed after the molding is completed, and may be included in the final product when using a ceramic material such as dark wool or mineral wool.

After filling the geopolymer paste into the mold, high temperature drying is performed for 24 hours in a drier operating at 70 to 90 ° C., and then room temperature curing is performed at room temperature for about 3 days.

As shown in FIGS. 4 to 5, the geopolymer molded body formed through the above manufacturing method, that is, the geopolymer block 14, has a small and uniform pore shape, which is required in an ALC block that is a non-combustible insulating material for construction. It can maintain compressive strength, insulation performance and a certain level of specific gravity.

On the other hand, the geopolymer block composition according to an embodiment of the present invention may be prepared by the above-described manufacturing method.

At this time, the geopolymer composition may include Hydroxycancrinite (Na ₈ Al ₆ Si ₆ O ₂₄ (OH, CO ₃ ) ₂ · 2H ₂ O). The Hydroxycancrinite may be produced in the above-described geopolymer formation process and may include crystalline. As described above, the molten slag discharged from the coal gasification complex power generation is in an amorphous form, and the hydroxycancrinite, which is crystalline as a result of the geopolymer forming process, is generated, so that durability of the manufactured porous geopolymer composition may be improved.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example  1: geopolymer paste To fill  Measurement of changes in compressive strength and specific gravity

Production Example  One

After washing the gasified coal slag with washing water, a drying process was performed such that moisture in the molten slag was within 10%. Thereafter, the molten slag in which the drying process was performed was subjected to a crushing process to have an average size of 80 to 120 ㎛.

Then, silicon sludge was supplied as a blowing agent to the molten slag in the form of pulverized particulates, but the silicon sludge was controlled to contain 0.10 to 0.50 wt%.

In this case, the mixed activator mixed solution is prepared by mixing an alkali activator (10-15 mol NaOH aqueous solution) and water glass (28.4% SiO ₂ , 9.4% Na ₂ O), the alkali activator and water glass in a 1: 1 ratio After supplying so that the liquid / solid (W / S) ratio of 20 to 30% by weight of additional water was supplied and then kneaded evenly.

Then, the kneaded geopolymer paste was filled with 30%, 65%, and 80% in the volume of the mold, and dried at 70-90 ° C. for 24 hours at high temperature, and then cured at room temperature for 3 days.

Experimental Example  One

According to Example 1, the compressive strength measurement results according to the filling amount of the geopolymer paste in the molding die is shown in FIG.

In this case, the compressive strength was measured by using a universal testing machine (UTM-900NH Series DAEKYUNG, Korea) and measured 3 to 5 specimens at a head speed of 5 cm / min as an average value.

Referring to FIG. 6, the compressive strength of the geopolymer paste filling amount was 80% or more than twice that of the geopolymer paste filling amount was 30%. That is, when the filling amount of the geopolymer paste is 30%, the compressive strength is about 6.5 MPa, when the filling amount is 65%, the compressive strength is about 8.5 MPa, and when the filling amount is 80%, the compressive strength is about 13 MPa.

Meanwhile, according to Example 1, specific gravity measurement results according to the filling amount of the geopolymer paste are shown in FIG. 7. Referring to FIG. 7, the specific gravity (apparent density) is about 0.7 g / cm ³ when the geopolymer paste filling amount is 30% or 60%, and the specific gravity is about 0.8 g / cm ³ when the geopolymer paste filling amount is 80%. .

In the case of the geopolymer block of the present invention, the compressive strength must be at least 7 MPa and the specific gravity is 0.7 g / cm 3. Therefore, the filling amount of the geopolymer paste is preferably 30 to 70.

Claims (10)

Mixing the molten slag and blowing agent to produce a geopolymer raw material;
Adding a complex activator mixed solution to the geopolymer raw material to produce a geopolymer paste; And
Molding the geopolymer paste to produce a geopolymer molded body,
Generating the geopolymer molded article,
Filling the geopolymer paste 40 to 70% of the volume of the mold; And
And discharging the gas generated from the geopolymer paste filled in the mold through the opening formed in the mold.
The method according to claim 1,
The blowing agent comprises from 0.10 to 0.50% by weight based on the geopolymer raw material, the method of producing a geopolymer block composition.
The method according to claim 1,
The blowing agent comprises a waste silicon sludge powder, method of producing a geopolymer block composition.
The method according to claim 1,
Wherein said composite activator mixed solution has a weight ratio of alkali activator to water glass of 1: 1.
The method according to claim 1,
The step of producing the geopolymer paste,
The geopolymer paste further comprises the step of supplying water to the water content / solid phase weight ratio in the liquid sample to 20 to 30% by weight and kneading evenly, the method of producing a geopolymer block composition.
The method according to claim 1,
Before the step of producing the geopolymer raw material further comprises the step of grinding the molten slag so that the average particle size of 80 ~ 120 ㎛, geopolymer block composition manufacturing method.
The method according to claim 1,
Generating the geopolymer molded article,
Drying the mold filled with the geopolymer paste at a high temperature for 24 hours in a dryer operated at 70 to 90 ° C .; And
Further comprising the step of curing the high temperature dried mold in room temperature for 3 days at room temperature, method of manufacturing a geopolymer block composition.
A geopolymer block composition produced by a method of preparing a geopolymer block composition according to any one of claims 1 to 7.
The method according to claim 8,
A geopolymer block composition comprising Hydroxycancrinite (Na ₈ Al ₆ Si ₆ O ₂₄ (OH, CO ₃ ) ₂ .2H ₂ O).
A geopolymer block comprising the geopolymer block composition according to claim 8.

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