KR101852037B1 - Manufacturing method of light weight geopolymer by using slag from waste spent catalyst and silicon sludge - Google Patents

Abstract

The present invention relates to the production of an environmentally friendly lightweight bubble geopolymer for replacing lightweight foamed concrete using existing cement, wherein 100% of waste catalyst slag, which is a waste generated in industry, is used without using conventional blast furnace slag or meta kaolin A blowing agent for lighter weight also uses a silicon sludge generated in a semiconductor wafer process, thereby disclosing a method for producing economical lightweight bubble geopolymers without generating a large amount of CO ₂ . The present invention is silica (SiO _2), alumina (Al ₂ O ₃₎ and calcia (CaO) a waste catalyst slag, silicon sludge and alkaline activator solution comprising, including the step of mixing, curing, and curing the light-weight foam Geo Wherein the mixed alkali activator solution has a concentration of 5 to 15 M and a water content ratio of the waste catalyst slag to the total weight of the silicon sludge is from 0.20 to 0.32. And a manufacturing method thereof.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a lightweight bubbling geopolymer using waste catalyst slag and a silicon sludge,

The present invention relates to a method for producing a geopolymer, and more particularly, to a method for producing a lightweight geopolymer using specific waste resources in a geopolymer synthesis process.

Since the conventional concrete structural material has a higher specific gravity than the strength thereof, there is a disadvantage that it increases the self weight of the structure. Therefore, lightweight concrete has been developed and used in various fields in order to improve these shortcomings and to give other excellent performance. Lightweight concrete is widely used not only for non-structural use but also for structural use. However, it is currently used as non-structural concrete for indirect effects such as insulation and sound insulation, rather than using structural concrete due to direct effect of reduction of weight. There are three types of lightweight concrete: lightweight aggregate concrete using porous lightweight aggregate with low specific gravity, lightweight foamed concrete with numerous air bubbles inside the concrete, and Autoclaved Lightweight Concrete (ALC).

Lightweight foamed concrete has been studied for its use as a part of insulation and soundproofing materials in European countries due to its thermal insulation properties. However, most of the lightweight concrete is a lightweight aggregate concrete or ALC (Autoclaved Lightweight Concrete) It is a fact that it is concentrated. In recent years, however, due to the fact that the lightweight foamed concrete in the field is insulated, the sound insulation performance between the upper and lower floors, the weight reduction of the structure and the construction of the ondol pipe are easy and the manufacturing and construction are possible in a relatively small area, (Korea Concrete Institute, The Latest Concrete Engineering, pp. 659-695 (2004)).

Traditionally, concrete is a construction material made by mixing cement, water, aggregate and admixture. The cement manufacturing industry consumes a large amount of energy and has the problem of producing limestone (CaCO ₃ ) and a large amount of CO ₂ gas when the fuel is burned have. The amount of CO ₂ generated in the cement manufacturing process accounts for 7% of global greenhouse gas emissions, which is increasing every year (GS Ryu, YB Lee, KT Koh, and YS Chung, Construction and Building Materials, 47, 409 -418 (2013)).

Geopolymers are eco-friendly inorganic binders that replace conventional cements and have been reported to have excellent physical and mechanical properties when reacted with pozzolans such as blast furnace slag, fly ash, and meta-kaolin (Davidovits J., Comrie DC Jr. Provis, P. Duxson, GC Lukey, Journal of Hazardous Materials, Vol. 12, No. 7, pp. 30-40 (1990), Paterson JH, and Ritcey DJ, ACI Concrete International, , A139, pp. 506-513 (2007)). Geopolymers also have amorphous three-dimensional network structures composed of alumino silicates, have excellent chemical durability and mechanical properties, and have the potential to be manufactured from industrial wastes or low-grade materials (Davidovits J., Comrie DC, J., J. Van Deventer, JL Provis, P. Duxson, GC Lukey, Journal of Hazardous Materials, Vol. 12, No. 7, pp. A139, pp. 506-513 (2007)). In the reaction mechanism of the geopolymer, when the alkaline environment is provided to the raw material of the aluminosilicate component, the Si and Al ions are eluted and the polymerization reaction proceeds rapidly, and a three-dimensional polymerization chain of Si-O-Al- (J. J. ≪ / RTI > Joshi and MS Kadu, Int. J. Environmental Science and Development, Vol. 3, No. 5 (2012); J. Davidovits, Concrete Technology Past Present and Future, Vol.144, 383-398 (1994)).

In particular, a bubble geopolymer refers to a porous material having a specific gravity of 2.0 or less, which is made for the purpose of weight reduction, and generally refers to a porous material produced by mixing bubbles by chemical reaction by mixing Al, Si powder or the like to make it lighter than porous bodies or concrete of the same volume . Lightweight bubble geopolymers are used in various fields such as structural, reinforced concrete coating, heat shielding, etc. by mixing bubbles in order to lighten the weight. It is necessary to develop a lightweight bubble geopolymer with a compressive strength of 1.5 MPa or more and an apparent specific gravity of 0.5 to 0.7 according to the KS F 4039 standard of cement mortar concrete in order to increase the utilization of the environmentally friendly inorganic binder.

Various studies have been made on a method for producing a geopolymer using waste resources. For example, waste glass (registered patent No. 1078336), building waste (registered patent No. 1120062), fly ash (registered patent No. 1315371) And a blast furnace slag (Patent No. 1218654).

Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an environmentally friendly lightweight bubble-free geopolymer for replacing lightweight foamed concrete using conventional cement. The use of 100% waste catalytic slag, which is the waste generated in industry, and the blowing agent for lighter weight also make use of the silicon sludge generated in the semiconductor wafer process, which can produce economical lightweight bubble geopolymers without generating a large amount of CO ₂ Method.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for mixing, curing and curing a waste catalyst slag, a silicon sludge and an alkali activator solution containing silica (SiO ₂ ), alumina (Al ₂ O ₃ ) and calcia (CaO) Wherein the mixed alkali activator solution has a concentration of from 5 to 15 M and a water content ratio of the spent catalyst slag to the total weight of the silicon sludge is from 0.20 to 0.32 And a method for manufacturing a lightweight bubble geopolymer.

The amount of the waste catalyst slag and the amount of the silicon sludge is 85 to 91 wt% of the waste catalyst slag and 9 to 15 wt% of the silicon sludge.

The waste catalyst slag and the silicon sludge content are 97 to 99% by weight of the waste catalyst slag and 1 to 3% by weight of the silicon sludge, and further water glass is mixed so that the water content ratio of the water glass to the liquid weight of the alkali activator solution 0.5 to 1.5. ≪ / RTI >

According to the present invention, a lightweight bubble-type geopolymer having a density of 1 or less can be produced by adding silicon sludge to waste catalyst slag, and 100% This makes it possible to manufacture eco-friendly inorganic binders that are economical and comparable to structural lightweight foamed concrete.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram illustrating a process for producing a lightweight bubble-generating polymer according to the present invention,
FIG. 2 is a graph showing XRD measurement results for the crystal phase analysis of silicon sludge in the embodiment of the present invention,
3 and 4 are graphs showing the results of measurement of the density and compressive strength of the lightweight bubbling geopolymer according to the variation of the W / S ratio and the amount of the added silicon sludge,
FIG. 5 is a graph showing the results of measurement of density and compressive strength of a lightweight bubbling geopolymer according to the use of a complex activator and a change in addition amount of a silicon sludge in an embodiment of the present invention,
FIG. 6 is a graph showing the results of measurement of density and compressive strength of a lightweight bubbling geopolymer according to changes in addition amount of a water activator of a complex activator in an embodiment of the present invention. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification. Also, throughout the specification, when an element is referred to as "including " an element, it means that it may include other elements, not excluding other elements, unless specifically stated otherwise.

The present invention is silica (SiO _2), alumina (Al ₂ O ₃₎ and calcia (CaO) a waste catalyst slag, silicon sludge and alkaline activator solution comprising, including the step of mixing, curing, and curing the light-weight foam Geo Wherein the mixed alkali activator solution has a concentration of 5 to 15 M and a water content ratio of the waste catalyst slag to the total weight of the silicon sludge is from 0.20 to 0.32. A manufacturing method is disclosed.

In order to manufacture a lightweight bubble geopolymer, 100% waste catalyst slag, which is produced by melting the waste catalyst at high temperature after exhaust gas purification, is used as a raw material of the geopolymer. In order to reduce the weight through bubble formation, Characterized in that a silicon sludge is added. In addition, an alkali activator solution such as an aqueous NaOH solution may be used alone as an activator for the geopolymer reaction through the hydration and heavy / condensation reaction of the waste catalyst slag, or a mixture of an alkali activator solution and water glass .

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a process diagram illustrating a process for producing a lightweight bubble-generating polymer according to the present invention.

Referring to FIG. 1, the lightweight bubbling geopolymer according to the present invention can be produced by, for example, dry mixing the waste catalyst slag and the silicon sludge according to the blending ratio, adding the alkali activator solution to the mixed raw material, Sealing, curing at 60 to 80 ° C and 12 to 36 hours, and after completion of curing, the specimen can be manufactured by demolding for 2 to 4 days.

The waste catalyst slag used in the present invention is mainly composed of silica (SiO ₂ ), alumina (Al ₂ O ₃ ) and calcia (CaO), and contains a small amount of magnesium oxide (MgO), iron oxide (Fe ₂ O ₃ ) . Preferably, the silica is contained in an amount of 28 to 32 wt%, alumina is contained in an amount of 34 to 38 wt%, and calcia is contained in an amount of 21 to 25 wt%. In the waste catalytic converter, Can be made by melting at high temperature. Such waste catalyst slag may be used by drying before mixing with an alkali activator solution described later, and may be used by drying at 100 to 120 ° C for about 12 to 36 hours.

Further, the silicon sludge used in the present invention is generated during a process of manufacturing a silicon wafer used for manufacturing a semiconductor device. A silicon wafer is produced by cutting a silicon ingot, and sludge containing silicon is produced during the process.

The spent catalyst slag uses a strong alkali activator can cause the reaction to elute the Si ^{4 +,} Al ^{3 +} ion which is involved in breaking the glass film geo-polymer reaction because it is not possible to geo-polymer reaction by itself, OH ^- the more the concentration of the decomposition is the coupling ₂ -Al ₂ O ₃ glass quickly SiO and produce large quantities of a reactive ion. Therefore, when the alkali ion concentration is high, the alkali activator as an important factor for the activation of the waste catalyst slag accelerates the decomposition of the reactant of the waste catalyst slag, and thus a geopolymer having high strength can be produced.

The alkaline activator is not particularly limited as long as it is a water-soluble alkaline hydroxide capable of reacting with the waste catalyst slag (pozzolanic reaction) to produce components such as silicates or aluminates having hydraulic properties. For example, an alkali activator solution having a concentration of 5 to 15M, preferably 7 to 11M, and more preferably 8 to 10M may be used as a solution in which distilled water is mixed with sodium hydroxide (NaOH) or potassium hydroxide (KOH). The alkali activator solution can be prepared, for example, by mixing sodium hydroxide at a proper concentration in distilled water and heating it to a temperature of 25 to 90 ° C and mixing.

The silicon sludge forms a hydrogen gas through a chemical reaction as shown in Reaction Scheme 1 when it is in contact with the alkali activator solution, and the gas collects and expands in the interior of the geopolymer, thereby making it possible to manufacture a lightweight foamed geopolymer.

[Reaction Scheme 1]

_{Si + 2NaOH + H 2 O →} Na 2 SiO 3 + 2H 2

At this time, the water content ratio of the alkali activator solution to the weight ratio of the silicon sludge addition amount to the total solid raw material weight, that is, the total weight of the waste catalyst slag and the silicon sludge influences the density and compressive strength of the lightweight bubbling geopolymer, The amount of the silicon sludge in the alkaline activator solution and the water content of the optimal alkaline activator solution may be present. According to the present invention, the concentration of the alkaline activator solution is 5 to 15M, The water content ratio in the solution (hereinafter, also referred to as 'W / S (water / raw material) ratio') is 0.20 to 0.32, preferably 0.23 to 0.31, more preferably 0.26 to 0.30, 0.28 to 0.30. When the alkaline activator solution is used alone, the optimal content of the silicon sludge may be 9 to 15 wt% (waste catalyst slag 85 to 91 wt%), preferably 12 to 15 wt% Wt% (waste catalyst slag 85 to 88 wt%).

In the present invention, a method for manufacturing a lightweight bubble geopolymer having a compressive strength of 1.5 MPa or more and an apparent specific gravity of 0.5 to 0.7 according to the KS F 4039 standard of the existing cement mortar concrete while minimizing the silicon sludge content is proposed do.

That is, the water sludge is further mixed with the alkali activator solution containing 1 to 3 wt% of the silicon sludge (97 to 99 wt% of waste catalyst slag), the water content of the water glass to the liquid weight of the alkali activator solution Ratio is in the range of 0.5 to 1.5 so as to satisfy the compressive strength and specific gravity standard. In this case, the water content ratio of the water glass is more preferably 0.8 to 1.2, most preferably 0.9 to 1.1.

Hereinafter, the present invention will be described in more detail by way of examples.

Spent catalyst Slag  And silicon Sludge  Basic properties

The spent catalyst slag used in this embodiment is made by recovering valuable metals from waste catalysts generated in an apparatus for purifying exhaust gas of automobiles and melting the remaining metals at high temperatures. Table 1 below shows the results (unit: wt%) of the chemical composition of the waste catalyst slag using X-ray fluorescence (XRF). As a main component, SiO ₂ , Al ₂ O ₃ and CaO are present in a large amount of 29.7, 35.8, and 22.7 wt%, respectively. Thus, the possibility of a lightweight bubbly geopolymer raw material through formation of Si-O- .

In addition, the silicon sludge used in this embodiment is generated during a silicon wafer manufacturing process used for manufacturing a semiconductor device. The silicon wafer is produced by cutting a silicon ingot, and sludge containing silicon is produced during the process. The chemical composition of this silicon sludge was analyzed by using X-ray fluorescence (XRF). The results are shown in Table 2 (unit: wt%). As a result of the chemical composition analysis, it was confirmed that SiO ₂ was the main component at 97.8 wt%. The results of the XRD measurement for the crystal phase analysis of the silicon sludge are shown in FIG. 2, and it was confirmed that the main component was silicon rather than oxide such as SiO ₂ .

W / S ratio and silicon Sludge  Lightweight bubbles Geopolymer  analysis

In Examples 1 to 10, NaOH was fixed at a concentration of 9M as an alkali activator, and lightweight bubbles were formed according to changes in silicon sludge addition amounts (3, 6, 9, 12, and 15 wt%) and W / S ratio changes (0.23, 3 and 4 show the results of measuring the density and compressive strength of the light-weight bubble-generating polymer prepared. The results are shown in Table 3 below. The lightweight bubble geopolymer was prepared by dry blending the waste catalyst slag and the silicon sludge according to the blending ratio, molding the cubic type mold (5 × 5 × 5 cm) by adding the alkali activator solution to the mixed raw material, After curing at 70 ° C and 24 hours, after the curing was completed, the specimens were aged for 72 hours after demolding.

Referring to FIG. 3, density of the geopolymer tends to decrease as the amount of silicon sludge added increases, regardless of the W / S ratio. The silicon sludge forms H ₂ (g) through a chemical reaction as in the above reaction formula 1 when it is in contact with the NaOH activator. The gas is captured and expanded inside the geopolymer to form a lightweight bubbling geopolymer.

In the case of a geopolymer having a W / S ratio of 0.29, the density of silicon sludge was decreased from 12 wt% due to the increase in the amount of silicon sludge added compared with the geopolymer having a W / S ratio of 0.23. The decrease of the density of the geopolymer is considered to be due to the improvement of the workability due to the decrease of the viscosity of the specimen. In addition, since the reaction of silicon sludge (see Scheme 1) is faster than the geopolymerization of spent catalyst slag, the increase of Na ⁺ ion with increasing W / S ratio promotes the formation of H ₂ (g) of silicon sludge Which is believed to have contributed to the weight reduction of geopolymers.

As shown in FIG. 4, when the W / S ratio was 0.23 and 0.29, the highest compressive strength (4.5 MPa, 10 MPa) was obtained when the amount of silicone sludge was 3 wt% And the strength tended to decrease. The decrease in compressive strength with increasing amount of silicon sludge is attributed to the weakening of the geopolymer matrix due to the macropores formed inside the geopolymer by foaming by the H ₂ (g) reaction of the silicon sludge. This result is consistent with the decrease in the density of the geopolymer as the sludge addition amount increases.

In Examples 9 and 10, in which NaOH alone activator was mixed with 12 wt% and 15 wt% of silicon sludge, the compressive strength was 1.5 MPa and the density was 0.6 ~ 08, and the specific gravity and compression of non-structural cellular concrete of KS F 4309 It is understood that the strength standard is satisfied.

Use of complex activators and silicone Sludge  Lightweight bubbles Geopolymer  analysis

In Examples 11 to 16, the W / S ratio was fixed to 0.29, and the composite activator prepared by mixing 50 wt% of water glass with 9M aqueous NaOH solution (based on water) was applied. The change in the addition amount of silicon sludge ), 1.0, 2.0, 3.0, 6.0% by weight) (see Table 4 below, unit: parts by weight), and the density and compressive strength of the lightweight bubble- Respectively.

Referring to FIG. 5, the density of the geopolymer prepared with the complex activator showed a tendency to decrease as the amount of the silicon sludge was increased. When the silicon sludge was added at 0.1 wt%, the geopolymer exhibited a density of 1.6, The density decreased rapidly to 0.42. Compressive strength also decreased sharply as the amount of silicon sludge was increased. When the amount of silicon sludge was more than 2 wt%, the compressive strength was low as 2 MPa. In the results of FIG. 3, the density of the geopolymers added with 3 wt.% And 6 wt.% Of silicon sludge without addition of water glass showed a density of 1.64 and 1.38, respectively. However, when using a complex activator mixed with water glass, Low densities of 0.62 and 0.44 were obtained at 3 wt.% And 6 wt.% Of the geopolymer, respectively.

In Example 14, in which 2 wt% of silicon sludge was mixed with NaOH and water glass, a compressive strength of 1.5 MPa and a density of 0.64 were obtained to satisfy the specific gravity and compressive strength of KS F 4309 non-structural cellular concrete , It can be confirmed that the addition amount of the silicon sludge required for the light weight is greatly reduced when the complex activator is used.

Lightweight bubbles with varying amounts of water activator Geopolymer  analysis

In Examples 17 to 27, the W / S ratio was fixed to 0.29 and the amount of added silicon sludge was set to 1% by weight. In the composite activator, light weight was changed according to the addition amount of water glass mixed with NaOH 9M solution (0 to 50% The bubble geopolymer was prepared (see Table 5, unit: parts by weight), and the density and compressive strength of the produced lightweight bubble-type geopolymer were measured and are shown in FIG.

Referring to FIG. 6, the density of the geopolymer tends to decrease gradually as the amount of water glass added in the composite activator increases. When the aqueous activator of the aqueous NaOH solution is not mixed with water, The density of water glass decreased sharply from 35 wt%, and the density of water glass added was lower than 1.0 at 50 wt%. Compressive strength increased with increasing amount of water glass, but showed the highest value at 18 wt% at 15 wt%. However, when the amount of water glass added was more than 15 wt%, the compressive strength tended to decrease as the amount of water glass added increased.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (3)

Silica (SiO _2), alumina (Al ₂ O ₃₎ and calcia producing a lightweight foamed geo-polymer including (CaO) Catalyst slag, mixing, curing, and curing the silicone sludge and alkaline activator solution comprising In this way,
Wherein the mixed alkaline activator solution has a concentration of 5 to 15 M and a water content ratio of the waste catalyst slag to the total weight of the silicon sludge is 0.23 to 0.31,
Wherein the waste catalyst slag and the silicon sludge content are 97 to 99% by weight of the waste catalyst slag and 1 to 3% by weight of the silicon sludge, and further water glass is mixed so that the water content ratio of the water glass to the liquid weight of the alkali activator solution is 0.8 ~ 1.2,
Wherein the lightweight bubbling geopolymer has a compressive strength of 1.5 MPa or more and an apparent specific gravity of 0.5 to 0.7. delete delete

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