KR100653311B1 - Cement composition for autoclaved lightwiht concrete production comprising heavy oil ash and manufacturing method of alc using the same - Google Patents

Abstract

The present invention relates to a composition for producing light-weight foamed concrete comprising heavy oil ash, and more particularly, to a composition for producing light-weight foamed concrete which is environmentally friendly and has high function by addition of heavy oil ash. The present invention (a) 20 to 70% by weight siliceous raw material; (b) 15-30 weight percent of Portland cement; (c) 5-25 wt% lime; (d) 0.05-4% by weight of aluminum paste; And (e) provides a cement composition for producing ALC comprising 5 to 30% by weight heavy oil ash. According to the present invention, heavy oil ash may be used as an additive to improve foaming performance in the ALC manufacturing process, and ultimately to improve mechanical properties of the ALC. In addition, it is possible to provide a cement composition for producing ALC, which replaces some of the materials used in ALC production, thereby increasing the throughput of heavy oil ash and does not cause a decrease in physical properties of the final ALC.

 Heavy oil ash, ALC, foaming performance, compressive strength

Description

Composition for manufacturing light foamed concrete containing heavy oil ash, method for manufacturing ALC using the same {CEMENT COMPOSITION FOR AUTOCLAVED LIGHTWIHT CONCRETE PRODUCTION COMPRISING HEAVY OIL ASH AND MANUFACTURING METHOD OF ALC USING THE SAME}

The present invention relates to a composition for producing light-weight foamed concrete comprising heavy oil ash, and more particularly, to a composition for producing light-weight foamed concrete which is environmentally friendly and has high function by addition of heavy oil ash.

It is a kind of lightweight concrete that has light weight by dispersing countless bubbles in concrete by blowing agent of autoclaved lightweight concrete (hereinafter referred to as 'ALC'). It is produced in the form of panel reinforced with blocks and reinforcing bars. In addition, it exhibits excellent performance in light weight, heat insulation, fire resistance and workability, which are general advantages of light weight concrete.

However, ALC is excellent in light weight, heat insulation, processability, dimensional stability, fire resistance, etc., but has disadvantages in mechanical properties such as high hygroscopicity and brittleness. The mechanical properties of ALC are closely related to the physical properties such as specific gravity, compressive strength, and tensile strength of ALC.The mechanical properties of ALC are maintained while maintaining excellent performance advantages such as light weight, heat insulation, fire resistance, and workability. It is necessary to provide good ALC.

Meanwhile, heavy oil ash generated from thermal power plants or boilers is composed of unburned carbon with 70 to 80% of its components, and inorganic oxides such as SiO ₂ and Al ₂ O ₃ in the glassy state, in addition to valuable metals such as vanadium and nickel. exist.

Up to now, most of the heavy oil ash generated from heavy oil-fired power plants has been used as a deoiling agent in the steel industry. However, when high oil sulfur oil is used, the sulfur component of heavy oil ash is rapidly increased and it is difficult to recycle as a deoiling agent.

On the other hand, researches for recycling heavy oil ash include recovering valuable metals from heavy oil ash, and incineration using a high-efficiency incinerator. Recently, some researches on activated carbon through pretreatment such as CO ₂ have been conducted. It is becoming.

On the other hand, Japanese Patent Laid-Open No. 6-9251 proposes a method for manufacturing artificial lightweight aggregate for lightweight concrete by mixing heavy oil ash with coal ash. This method can solve the problem of poor sintering of light weight aggregate manufactured from conventional coal ash by utilizing unburned carbon contained in heavy oil ash.

In addition, studies on the use of cement admixtures have been conducted using the characteristics of the constituents constituting heavy oil ash. Korean Patent Laid-Open Publication No. 10-2004-82094 has proposed a hydraulic composition that utilizes the color represented by carbon black, the main component of heavy oil ash, as a black pigment of cement and at the same time uses the subsidiary silica and alumina as potential hydraulic substances. .

However, to date, such heavy oil recycling is not widely applied. Moreover, in Korea, the use of high-sulfur heavy oil in heavy oil-fired power plants is expected to increase the domestic production of heavy oil ash to over 30,000 tons after 2005. Therefore, there is a need for various studies on building materials whose properties can be enhanced by the addition of heavy oil ash.

An object of the present invention is to provide a cement composition for preparing ALC which can improve the physical properties of ALC using heavy oil ash as an additive.

Furthermore, an object of the present invention is to provide a cement composition for producing ALC, which does not cause a decrease in physical properties of the final ALC while increasing the throughput of heavy oil ash by replacing some materials of the material used for preparing the ALC.

It is also an object of the present invention to provide a method for producing ALC from the cement composition and the ALC produced thereby.

In order to achieve the above technical problem (a) 20 to 70% by weight siliceous raw material; (b) 15-30 weight percent of Portland cement; (c) 5-25 wt% lime; (d) 0.05-4% by weight of aluminum paste; And (e) provides a cement composition for producing ALC comprising 5 to 30% by weight heavy oil ash.

The composition may further include 1 to 5% by weight of far-infrared and negative ion co-radiator with respect to the weight of the composition.

In another aspect, the present invention provides a raw material for manufacturing ALC comprising 20 to 70% by weight of siliceous raw material, 15 to 30% by weight of Portland cement, 5 to 25% by weight of lime, 0.05 to 4% by weight of aluminum paste and 5 to 30% by weight of heavy oil ash. step; Molding, preliminary curing and demolding the mixed raw materials; And autoclaving the demolded block under high temperature and high pressure.

The present invention also provides an ALC block prepared by the above-described method, which contains heavy oil ash and has an SO ₃ content of 2.5 to 4%.

The ALC of the present invention forms a slurry by mixing lime, siliceous raw material, foaming agent, and admixture with water as a main raw material and making a slurry through steam curing in an autoclave of high temperature and high pressure (180 ° C, 10㎏ / ㎠). It is prepared by the process of forming Tobermorite crystals of the structure.

Hereinafter, the raw material used for the ALC manufacturing method of this invention is demonstrated.

As the siliceous raw material, silica or silica may be used. The silica and / or silica sand (hereinafter referred to as 'silica sand') is preferably included in about 20 to 70% by weight based on the total content of the composition.

The siliceous material has a pozzolanic action during ALC production, and there is a slight difference depending on the properties of cement and lime, the powder degree of pozzolan, foaming and curing method, but a high content of SiO ₂ is generally advantageous for improving compressive strength. In addition, in order to increase the number of bonding of silica and lime in the crystal structure inside the ALC, an increase in the adhesion surface is required. Therefore, the higher the powder density, the better the compressive strength is. Therefore, the silica sand is preferably pulverized with a wet mill to have a powder degree in the range of about 2200 ~ 3400 cm ² / g.

In the present invention, as a raw material for lime, both hydrated lime and quicklime can be used, but the hydrated lime has a phenomenon in which condensation is delayed at room temperature, and it is preferable to use quicklime. In the case of using quicklime, exothermic reaction is carried out by hydration reaction in the process of reacting with SiO ₂ by hydrothermal reaction in autoclave to form Tobermorite crystal structure as well as raw material blended in slurry form into semi-plastic body It can promote the hydration of low popland cement and foaming of Al powder, fix the mixed water and express the hardness.

In addition, quicklime, when contacted with water, absorbs large amounts of water into a number of very fine pores, causing hydration. This reaction is a very effective grinding process, and Ca (OH) ₂ has a significant expansion force compared to CaO, and after a few minutes, it changes to a dispersed slurry in which very fine white powder or fine particles are distributed depending on the amount of binding water. .

As the aggregates of the fine particles are dried, the binding force is increased, and the action can shorten the autoclave curing period, and the higher the purity and powder of the quicklime itself, the greater the effect.

The quicklime circuit is preferably 85% to 90% CaO, MgO 1% or less quicklime. In the present invention, the lime is preferably included in about 5 to 25% by weight based on the total weight of the mixed raw material.

In the present invention, cement is generally used mainly popland cement, but sometimes the use of crude steel cement is also possible. When Al powder is used as a blowing agent, the amount of alkali components such as Na ₂ O and K ₂ O in cement affects the rate of foaming, the amount of foaming, and the size and distribution of bubbles from the slurry phase along with the hydration temperature of the cement. Therefore, in order to manufacture ALC of relatively constant quality, homogeneous components and use of cement of constant quality are required. In the mixed raw material of the present invention, the cement is preferably contained about 15 to 30% by weight.

Various kinds of materials may be used as the blowing agent, but it is preferable to use aluminum powder or aluminum paste in consideration of economical efficiency, reaction control properties, and the like. Since the aluminum powder is very strong in water repellency in itself and is required to be uniformly dispersed in the ALC slurry, it is preferable to use a product having low water repellency. The content of Al is preferably 0.05 to 4% by weight.

The generation of air bubbles by aluminum in the manufacturing process of ALC can be explained by the following chemical reaction.

2Al + Ca (OH) ₂ + 2H ₂ OCaAl ₂ O ₄ + 3H ₂

2Al + 2NaOH + 2H ₂ O.2NaAlO ₂ + 3H ₂ (NaOH: added as foaming accelerator)

Hydrogen gas produced by the above reaction may move upward due to the specific gravity difference, and in some cases, escape to the outside, so that some admixture is used for the purpose of stably and uniformly dispersing bubbles in the slurry.

The generation of hydrogen gas is terminated around 20 minutes, but if the flow is severe even after the expansion is completed, bubbles may disappear and there is a fear of volume settlement. In addition, when curing starts before the expansion ends, the bubble shape becomes flat and its distribution is uneven, resulting in an increase in specific gravity. In order to prevent such a point, it is important to cure at the same time as the termination of foaming. This time adjustment should be adjusted in consideration of the effects of temperature during ALC manufacture, particle composition in Al powder or paste, mixer, dispersant, etc. used.

The composition of the present invention contains heavy oil ash. In the heavy oil ash, 70 to 80% of its components are unburned carbon, and inorganic oxides such as SiO ₂ and Al ₂ O ₃ are present in a glassy state in addition to valuable metals such as vanadium and nickel.

As can be seen in the examples of the present invention described below, the added heavy oil ash improves the foaming performance of ALC. This is presumably due to the fact that heavy oil ash is distributed into porous even particles and contains spherical fine pores.

In addition, the added heavy oil ash serves as an auxiliary binder. This is because the inorganic oxide contained in the heavy oil ash is present in the glassy state, and thus has latent hydrophobicity, and is caused by the hydration of the hardened cement during the cement hydration process.

In addition, the added heavy oil ash serves as a black pigment to change the color of the prepared ALC.

In addition, as can be seen in the examples described below, the heavy oil containing heavy oil ash having a sulfur compound content of 5% or more results in the improvement of compressive strength, the stability of the semi-plastic body, and the effect of shortening the molding time. In addition, the use of high sulfur containing heavy oil ash can reduce the shrinkage of ALC and improve freeze-thaw resistance.

The heavy oil ash in the composition of the present invention is preferably added 5 to 30% by weight. In particular, from the viewpoint of compressive strength, it is preferable that heavy oil ash within 7 to 14% of the total composition is added. However, heavy oil ash of more than this range may be added in place of the silica sand, and even at this time, the mechanical properties of the ALC, such as compressive strength, may be improved, and in manufacturing ALC blocks or panels, cost reduction may be obtained.

When the content of heavy oil is more than 30% by weight, the tobermorite forming reaction does not proceed and the specific gravity is very low, so that it cannot be used as an ALC block.

The ALC manufacturing cement composition of the present invention may further include a admixture for producing the ALC block. The admixture is a foaming accelerator to compensate for the lack of alkali and promote foaming, a dispersant for the purpose of evenly dispersing each component consisting of a slurry phase, to maintain the bubbles in the slurry, to prevent the aggregation of bubbles, Coercion and the like. Addition amounts and components of such admixtures are well known to those skilled in the art.

Gypsum and lime, which are currently used as admixtures, can increase the strength by adding an appropriate amount in the case of hydrothermal reaction. In addition, hydration of quicklime is suppressed during the foaming process of the slurry, but the effect of controlling the state of foaming by water-soluble lactate is good. It is known.

In addition, in the case of the steel for adjusting the curing time, the strength of the ALC is slow in foaming when compared to the concrete, and thus, many inconveniences and breakages occur during the time of demolding and the handling of the product. Prevention is possible.

Gypsum (CaSO ₄ · 2H ₂ O) among the raw materials can be added in the form of natural or anhydrous gypsum, which is preferable to use an appropriate amount experimentally because it affects the properties of ALC depending on the content of SO ₃ in the final ALC product. And, 2 to 5% by weight based on the whole composition can be used.

Moreover, according to another aspect of this invention, it is preferable that the composition for ALC manufacture of this invention contains a far-infrared and anion simultaneous radiator.

The far-infrared and anion simultaneous emitter preferably contains about 1 to 20% by weight of monazite rare earth ore based on the total weight of the emitter. The far infrared and anion co-radiators can be produced by the following method.

A mixture of 38 to 43% by weight of silica, 2 to 4% by weight of acetic acid, 2 to 5% by weight of alumina, 20 to 25% by weight of boric acid, 14 to 27% by weight of soda ash, and 5 to 11% by weight of calcium carbonate are placed in a container. After grinding for 30 to 60 minutes, the mixture is put into a melting furnace at 1200 to 1400 ° C., calcined for 1 to 3 hours, and then quenched and ground. Thereafter, 1 to 20% by weight of the monazite rare earth mineral is added to the pulverized product, which is then pulverized to produce a particle size of 200 mesh or less. The far-infrared and anion co-radiators manufactured in this way have a maximum wavelength in the wavelength range of 5 to 24 μm, have far-infrared emissivity of about 0.93 to 0.95, and anion emission is more than 600 / cc. Tourmaline (tourmaline) may be used in addition to the monazite mineral to obtain the anion release effect. At the firing temperature of 1200 ° C. or less, additives are not sufficiently melt mixed, resulting in inhomogeneity of the produced radiator. If exceeded, there is a disadvantage of lowering emissivity by incorporation of impurities due to corrosion of the melter.

The alumina and boric acid in the manufacturing method of the simultaneous simultaneous infrared and anion emitter is to lower the calcining temperature of the silica, soda ash, potassium acetate and calcium carbonate further lowers the calcining temperature of the silica and at the same time serves to increase the far-infrared emissivity of the short wavelength region beneficial to the human body Do it. In addition, tourmaline and monazite rare earth minerals increase anion release effect.

The far-infrared and anion co-radiator is preferably added 1 to 5% by weight with respect to the total weight of the cement composition for producing ALC.

ALC production by the composition of the present invention described above can be prepared through the seven steps of grinding and combination of raw materials, preparation of reinforcing materials, raw material mixing, molding, preliminary curing, demolding and cutting, autoclave curing.

The pulverization and combination of the raw materials are prepared by appropriately dry grinding and grinding the calcined raw material, silica sand and cement, which are the main raw materials of ALC, in the case of the panel, which is performed in parallel with the preparation of the reinforcing material.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention.

Examples 1-5

According to the formulations described in Tables 2 to 3, sand slurry, cement, quicklime, and aluminum paste are mixed to a weight of about 7 kg and stirred, and heavy oil ash is added. Heavy oil ash is added to the total composition weight of 6.9, 13.8, and 20.7. It was added in a weight percent of freshwater (Examples 1 to 3).

In addition, in order to find out whether the ALC raw material can be replaced with heavy oil, the water mixture was also changed to replace 15 and 30 wt% of the sand slurry blended with heavy oil and maintain a constant viscosity (Example 4-5).

Table 1 below shows the physical properties of heavy oil ash in Pyeongtaek thermal power plant used in the examples.

Dimension type Water content (%) Specific gravity (g / ml) Porosity (%) SO ₃ content (%) Pyeongtaek high sulfur heavy oil society 37.58 0.30 71.36 6.21

The compounding process is as follows. First, heavy oil ash is added to the sand slurry at each level, and cement and water are mixed, but only half of the total amount of water is added first and mixed with a stirrer. After mixing for about 30 seconds, the aluminum paste is mixed, quicklime and remaining water are added and stirred for 1 to 2 minutes. After mixing the raw materials, each level is put into 0.014㎥ styrofoam mold and cured until a certain hardness is reached in the curing room at 80 ° C., and then demolding is generally based on hardness of 400 or more and the time required is about 6 hours. The cured test piece was placed in an autoclave maintained at 150 to 180 ° C. and 10 atm to cure for 12 hours to prepare an ALC block.

Category (g) Addition amount Heavy oil society Sand slurry cement quicklime Al paste water Example 1 6.9% addition 346.7 3500 1090 440 3.7 600 Example 2 13.8% addition 693.3 3500 1090 440 3.7 900 Example 3 20.7% foreign addition 1039.9 3500 1090 440 3.7 900  Mold volume: 0.0143㎥

Category (g) Addition amount Heavy oil society Sand slurry cement quicklime Al paste water Example 4 Sand Slurry Replacement (15%) 525 2975 1090 440 3.7 1400 Example 5 Sand Slurry Replacement (30%) 1050 2450 1090 440 3.7 2300  Mold volume: 0.014㎥

Examples 6 and 7

According to the compounding table of Table 4 below, 1.4 and 2.8 wt% of far-infrared and anion co-radiators were added to the composition. No heavy oil ash was added in this example. The manufacturing process of the remaining ALC blocks was the same as in Examples 1-5.

Category (g) Addition amount Simultaneous radiator Sand slurry cement quicklime Al paste water Example 6 Far infrared ray anion simultaneous radiator (1.4% 69.33 3500 1090 440 3.7 600 Example 7 Far infrared ray anion simultaneous radiator (2.8% 138.7 3500 1090 440 3.7 900  Mold volume: 0.014㎥

Comparative Example 1

For comparison with the examples of the present invention, ALC blocks were prepared according to the method described in Examples 1 to 7 above, in which ALC blocks without heavy oil ash and far-infrared and anion co-radiators were added according to the formulation table shown in Table 5. .

Category (g) Addition amount Sand slurry cement quicklime Al paste water Comparative Example 1 ALC Block 3500 1090 440 3.7 600 Mold volume: 0.014㎥

Examples 1 to 7, after demolding the ALC block prepared through the process of Comparative Example 1, each foaming performance, dry weight, compressive strength performance was evaluated, chromaticity analysis, SO ₃ content analysis.

The foaming performance is mixed by pouring the raw material for each level of ALC in a styrofoam mold of 0.014m3 (0.24 × 0.24 × 0.24m) size, and after the curing process as described above, ALC is demolded from the styrofoam mold and then demolded ALC. The height was measured using a general ruler to express it as the foam height.

The dry weight and compressive strength were measured according to KSF 2701. For chromaticity measurement, place the specimen horizontally using a Spectrophotometer (CM-3500d, minolta colorimeter), adjust the colorimeter based on the calibration of the primary standard, read the values, and repeat three times for each specimen. The number was measured and the average value was recorded (L, a, b value).

Anion was measured by sealing 100 g of powdered raw materials in transparent vinyl and then sealed by ION TESTER, and the far infrared emissivity and radiant energy were measured using a black body using FT-IR of M 2400-C of MIDAC. (Black Body) The measurement result is shown. Far-infrared emissivity was measured in the range of 5 ~ 20㎛ wavelength and the surface temperature of the specimen was maintained at 40 ℃.

SO ₃ content was measured using a sulfur elemental analyzer. This is a method of quantifying the content of SO ₃ in the raw material by measuring the amount of SO ₂ gas generated when the raw material is decomposed at high temperature with an IR detector. At this time, it was measured by adding a certain amount of Fe, W as a supporting agent to assist the combustion to 100 mg of the raw material and injecting O ₂ gas to decompose at high temperature.

Table 5 shows the measurement results of the physical properties of the above-described Examples and Comparative Examples.

Item division Foam height (cm) Weight ratio Compressive strength (kg / ㎠) SO ₃ content (%) Far Infrared Emissivity Negative ion (pcs / cc) Chromaticity L a b Comparative Example 1 168 0.52 41.45 2.16 0.81 311 64.15 1.78 1.45 Example 1 173 0.52 64.4 3.02 - - 61.14 0.41 1.02 Example 2 188 0.52 62.4 3.82 - - 58.12 0.60 1.41 Example 3 195 0.51 40.9 3.98 - - 57.04 0.44 1.23 Example 4 196 0.52 42.8 3.49 - - 53.89 0.36 1.18 Example 5 202 0.50 45.0 4.67 - - 35.91 0.19 0.63 Example 6 167 0.52 38.3 - 0.92 602 81.87 2.87 6.03 Example 7 177 0.52 37.3 - 0.92 725 82.66 2.73 6.02

As a result of demolding the test pieces of Examples 1 to 7 of the present invention, the surface state of each block was generally clean without cracks, and the pore distribution was uniform.

As can be seen from Examples 1 to 5 of Table 5, the higher the amount of heavy oil ash added, the higher the foam height in ALC block curing. This is because heavy oil ash is distributed into porous even particles and contains spherical fine pores, thus improving foaming performance. Therefore, it can be seen that the added heavy oil ash may serve to assist the blowing agent. Examples 6 and 7 containing the far infrared and anion co-radiator showed no difference in the foaming height from Comparative Example 1.

In addition, from Table 5, it can be seen that the compressive strength is greatly improved when the amount of heavy oil ash added is 6.9, 13.8% by weight, and in other examples, the heavy oil ash added specimens generally have higher strength than the comparative sample. This result was also correlated in the result of measuring SO ₃ content. As the amount of heavy oil ash added, the amount of SO _{3 was} also increased, which also affects the improvement of physical properties of ALC as mentioned in the influence on the ALC properties of SO ₃ . You can see how crazy. In particular, when the SO ₃ content is in the range of 2.5 to 4%, the improvement of the foaming performance and the compressive strength of the ALC was remarkable.

In the dry weight ratio, the change according to the amount of heavy oil ash was not large, but the specific gravity of the block prepared by replacing the heavy oil circuit sand slurry by 30% by weight was lower than that of Comparative Example 1. Due to the low specific gravity and porosity of heavy oil ash, when the amount is added above a certain amount, the amount of bubbles in the ALC block increases and the foaming performance is very high.

In addition, as a result of measuring the far-infrared emissivity, which is the bio performance expected in the present invention, in the test specimen to which the far-infrared and anion co-radiator was added, although the addition amount of the far-infrared and anion co-radiator was small, the far-infrared emissivity and anion emission amount were improved. In Examples 6 and 7, the far-infrared emissivity was 0.92. The amount of negative ions released also exhibited better release characteristics than Comparative Example 1 in the specimens to which the co-radiator was added.

Heavy oil ash added to the cement composition of the present invention improves foaming performance during ALC manufacturing. In addition, the heavy oil ash added according to the present invention improves mechanical properties such as compressive strength of the finally produced ALC, and is capable of black expression.

It can be seen that the composition and preparation method of the present invention can replace the silica sand in the conventional ALC manufacturing raw material of heavy oil circuit. As a result, the ALC manufacturing cost can be lowered, and a large amount of heavy oil ash can be recycled.

Claims (4)

(a) 20 to 70 wt% of siliceous raw materials; (b) 15-30 weight percent of Portland cement; (c) 5-25 wt% lime; (d) 0.05-4% by weight of aluminum paste; And (e) 5 to 30% by weight of heavy oil ash cement composition for producing ALC. The method of claim 1, The composition is a cement composition for producing ALC, characterized in that it further comprises 1 to 5% by weight of far-infrared and anion co-radiator with respect to the weight of the composition. Providing a raw material for producing ALC comprising 20 to 70 wt% of siliceous raw material, 15 to 30 wt% of Portland cement, 5 to 25 wt% of lime, 0.05 to 4 wt% of aluminum paste, and 5 to 30 wt% of heavy oil ash; Molding, preliminary curing and demolding the mixed raw materials; And Autoclaving curing the demolded block. delete