KR101735094B1 - Method of preparing ciment binder from concret waste - Google Patents

Abstract

The present invention relates to a method for producing a cement binder by wet-treating waste concrete and, more specifically, to a production method of a cement binder having excellent hydration reaction by pulverizing waste concrete, and producing the cement binder through a wet process washing and heat treatment, and to a cement binder produced therefrom.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a cement binder from waste concrete,

The present invention relates to a method of producing a cement binder by wet treatment from waste concrete, and more particularly, to a method of producing a cement binder by pulverizing waste concrete, followed by wet processing by washing and heat treatment, And a cement binder produced therefrom.

The amount of construction waste generated is continuously increasing due to the deterioration of the existing structure, which causes the increase of total waste generation. Especially, the amount of waste concrete is 49,352 (ton / day), which is about 18 million tons per year. The amount of waste concrete is rapidly increasing year by year, but since it does not find proper recycling plan, it is simply used as a roadbed material or landfill. The importance of recycling is increasing more than ever before.

In addition, since 60-65% of the construction waste is waste concrete, it is important to increase the recycling rate of waste concrete in order to increase the recycling rate of construction waste. Also, waste concrete has a higher value as a valuable oil resource than other wastes Many developers have been dealing with development topics for a long time.

Currently, the recycling technology of waste concrete powder is disclosed in Korean Patent No. 10-0582770, which discloses a method of manufacturing a high-performance concrete for eco-friendly retaining wall by using waste concrete fine powder having a density of 1.0 to 1.5 and a particle size of 5 to 200 탆 However, it is a wet process that produces waste concrete fine powder in the form of slurry. Due to its low density, it is difficult to commercialize it because of the uneconomical aspect of adding separate reinforcing materials such as recycled aggregate, fly ash, fly ash and silica fume. have.

Korean Patent No. 10-0857101 discloses that 10 to 50.8 parts by weight of waste concrete fine powder having a particle size of 0.074 mm or less, a density of 1 to 1.2, and a water absorption rate of 5 to 6 wt% based on 10 parts by weight of a cement binder; And 14.3 to 23.7 parts by weight of water are known. However, this density is lower than the average density of silica sand of 2.2 or more, which causes a problem of lowering the bending strength and compressive strength.

However, the above-mentioned technology has not been used in terms of utilization of hydration property, and is not utilized as a material requiring hydration reaction, as it is merely used as a mixed material by removing only some foreign substances from waste concrete .

KR 10-0857101 B1

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a method of manufacturing a cement binder having improved hydration reaction by pulverizing waste concrete, washing and drying the heat treatment do.

Another object of the present invention is to provide a cement binder produced from the above production method.

In order to solve the above-mentioned problems, the present invention provides a method for producing waste concrete fine powder by pulverizing waste concrete (step 1); Washing the waste concrete fine powder (step 2); Heat treating the washed waste concrete fine powder (step 3); And separating the sand and the cement binder from the waste concrete fine powder after the heat treatment (step 4). In the step 3, the heat treatment is performed using a rotary dryer at a temperature of 400 ° C to 1,000 ° C. To provide a method for producing a cement binder.

In a preferred embodiment of the present invention, the crushing in the step 1 may be carried out using at least one apparatus selected from the group consisting of a crusher, a crusher and a crusher.

In a preferred embodiment of the present invention, in the step 1, the pulverization may be such that the powdery degree of waste concrete is 3,000 cm ² / g or more.

In a preferred embodiment of the present invention, in the step 1, the pulverization may be such that the powdery degree of the waste concrete is 3,000 cm ² / g to 5,000 cm ² / g.

In a preferred embodiment of the present invention, the waste concrete fine powder in step 1 may have an average particle size of 10 mu m to 2000 mu m.

In a preferred embodiment of the present invention, the washing in step 2 may be performed at room temperature using a spray screen.

In a preferred embodiment of the present invention, the spraying may be spraying under high pressure at a pressure of 2 kg / cm ² to 4 kg / cm ² .

In a preferred embodiment of the present invention, the method may further include adding at least one of a defoaming agent and a flocculant to the waste concrete before the washing of step 2 and mixing the same.

In a preferred embodiment of the present invention, the method further comprises the step of adding and mixing a coagulant and a defoamer to the pre-cleaned waste concrete powder of step 2, wherein the coagulant and defoamer are added in a weight ratio of 1: 1 to 6 .

In a preferred embodiment of the present invention, the rotary dryer may include a rotating body, a crusher, a heat generator, a speed controller, and a temperature controller.

In a preferred embodiment of the present invention, the heat treatment may be performed at a temperature of 600 ° C to 800 ° C.

In a preferred embodiment of the present invention, the heat treatment may be performed until the water content becomes less than 3%.

In a preferred embodiment of the present invention, the heat treatment may be performed until the water content becomes 0.5% to 3%.

In a preferred embodiment of the present invention, the separation may be performed using a dust collector.

In addition, the present invention provides a cement binder produced by the above production method.

In a preferred embodiment of the present invention, the cement binder may include silicon dioxide (SiO ₂ ), calcium oxide (CaO), and magnesium oxide (MgO).

In a preferred embodiment of the present invention, the cement binder may include 10% by weight to 50% by weight of calcium oxide (CaO) and magnesium oxide (MgO).

In a preferred embodiment of the present invention, the cement binder may have a density of 2.2 g / cm < ³ > to 2.5 g / cm < ³ >.

In a preferred embodiment of the present invention, the cement binder is selected from the group consisting of a concrete admixture, an afphalite filler, a solidifying pan base, a cement binder additive, a filler, an immobilizing agent for preventing migration, an acid soil improver, Lt; / RTI >

The production method according to the present invention can produce a cement binder which is excellent in environmental friendliness and economical efficiency, and has low foreign matter and easy hydration reaction by using waste concrete as a raw material.

Further, the cement binder according to the present invention has a low water content and excellent hydration reactivity and can be easily applied as a solidifying agent for an artificial soil solidifying agent and a slurry solidifying agent.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed in an ordinary or dictionary sense and the inventor can properly define the concept of the term to describe its invention in the best possible way It should be construed as meaning and concept consistent with the technical idea of the present invention.

The present invention provides a method for producing a cement binder which is excellent in environmental friendliness and economical efficiency by using waste concrete as a raw material, and which is small in foreign matter and easy hydration reaction.

Waste concrete generated by the dismantling of facilities by reconstruction and activation of redevelopment projects is mainly buried and processed. However, as the number of years of use increases, the amount of waste concrete is increasing, and the landfill site becomes difficult to secure. Therefore, there is a growing interest in using waste concrete in terms of environmental preservation and resource recycling. Therefore, a technique of crushing waste concrete and utilizing it as a material for cement binder or concrete has been proposed and utilized. However, the above-mentioned technology has only been used as a mixed material by simply pulverizing and burning waste concrete by dryly removing a part of foreign substances, and has not been approached in terms of application of hydration property, There is a disadvantage that they can not be utilized as materials.

Accordingly, the present invention provides a method for producing a cement binder having improved hydration reactivity by using waste concrete as a raw material and performing wet treatment.

The method for producing a cement binder using the wet treatment according to an embodiment of the present invention comprises the steps of (1) preparing waste concrete fine powder by pulverizing waste concrete; Washing the waste concrete fine powder (step 2); Heat treating the washed waste concrete fine powder (step 3); And separating sand and cement binder from the waste concrete fine powder after the heat treatment (step 4).

The heat treatment may be performed using a rotary dryer at a temperature of 400 ° C to 1,000 ° C.

The waste concrete according to an embodiment of the present invention may include a foreign matter, a sand component and a cement binder component. Here, the foreign matter may include other materials excluding the sand component and the cement binder component, such as waste vinyl, , Waste styrofoam, etc., collected at the time of waste concrete collection.

The term "cement binder " as used in the present invention may be an inorganic substance which hardens when kneaded with water or a solution and can act as an adhesive or an adhesive.

The step 1 is a step for pulverizing waste concrete to remove foreign matter and producing fine powder. The waste concrete can be pulverized to remove foreign matter from the pulverized product, and the dust can be recovered to produce waste concrete fine powder.

At this time, the pulverization may be carried out using at least one apparatus selected from the group consisting of a crusher, a crusher and a crusher.

The crusher means a machine for crushing a solid such as rock or waste, and is not particularly limited as long as it can produce the desired fine powder. However, the crusher may be a rotary shear crusher, a rotary impact crusher, a compression crusher, Screen type crusher.

The pulverizer means a machine for finely crushing a solid. The pulverizer is not particularly limited as long as it can produce a desired fine powder, and may be, for example, a jock lasher, a roll mill (heavy chain), or a jet mill.

The grinding machine refers to a machine for finely crushing solids such as rocks and ores, and is not particularly limited as long as the desired fine powder can be produced. For example, a griddle mill, a ball mill, a conical roll mill, It may be an atritha-silane group.

Meanwhile, in the pulverization according to an embodiment of the present invention, the crusher, the crusher and the crusher may be used in combination according to the target fine powder. For example, it may be first crushed using a crusher, and then second crushed by using a crusher or a crusher to obtain finer fine powder.

Specifically, the pulverization may be performed by pulverizing the pulverized waste concrete so that the pulverulence of waste concrete is not less than 3,000 cm ² / g by using the apparatus as described above. Preferably, the pulverization may be such that the pulverization degree of the waste concrete is from 3,000 cm ² / g to 5,000 cm ² / g.

The fineness is a measure of the degree of fine powder, and the higher the degree of powder, the better the hydration reaction. On the other hand, the powdery diagram was measured using a powder tester S1-510 (Blaine Air-Permeability Apparatus).

In addition, the waste concrete fine powder may have an average particle size of 10 탆 to 2000 탆. Preferably, the waste concrete fine powder may have an average particle size of 10 mu m to 1000 mu m.

The step 2 is a step for cleaning the waste concrete fine powder to remove the remaining foreign matter, and the washing may be performed using a spray screen.

The washing may be performed two or more times at room temperature using a spray screen. At this time, the normal temperature may be a temperature ranging from 15 ° C to 35 ° C. Specifically, the spraying may be a high-pressure spraying under a pressure condition of 2 kg / cm ² to 4 kg / cm ² . If high-pressure spraying is performed under the above-described pressure conditions, the cleaning may be easier and the foreign matter may be effectively removed.

At this time, the spraying screen can be used as long as it can easily carry out the desired washing, but it may be, for example, spraying vibrating screen.

Specifically, the spraying screen may include a conveyer for conveying the screen, a screen for placing waste concrete powder, and a washing water spraying device for spraying wash water onto the waste concrete fine powder. At this time, when the spray screen is a spraying vibration screen, the screen may be a vibration screen. The waste concrete fine powder is placed on a screen and can be cleaned by spraying water sprayed from a washing water spraying device while being conveyed by a conveyor. In addition, in the case of a vibrating screen, the vibration screen can be moved by vertical vibration, and the washing can be made easier by the dropping.

In addition, the manufacturing method according to an embodiment of the present invention may further include adding at least one of a defoaming agent and a flocculant to the waste concrete fine powder before the washing.

At this time, the defoaming agent and the flocculating agent act to suppress bubbles in the finally produced cement binder and increase the cohesion force of the particles, and the porosity of the cement binder can be reduced by introducing the flocculating agent.

The flocculant may be included in an amount of 5 to 10 parts by weight, preferably 7 to 10 parts by weight based on 100 parts by weight of the waste concrete fine powder. The flocculant is not particularly limited, and any of those conventionally known in the art may be used as desired.

The defoaming agent may be included in an amount of 10 parts by weight to 30 parts by weight, preferably 10 parts by weight to 20 parts by weight, based on 100 parts by weight of the waste concrete fine powder. When the defoaming agent is contained in an amount of less than 10 parts by weight based on 100 parts by weight of the fine powder of waste concrete, the effect of removing air bubbles inside the particles may be insignificant and the porosity may be increased. When the defoaming agent is more than 30 parts by weight, There may arise a problem that the economical efficiency is deteriorated due to an increase in price due to the use of defoamer. The antifoaming agent is not particularly limited and may be any of those conventionally known in the art.

Preferably, the method may further include adding a coagulant and a defoaming agent to the waste concrete powder before washing, wherein the coagulant and the defoaming agent may be added in a weight ratio of 1: 1 to 6.

The step 3 is a step of heat-treating the washed waste concrete fine powder in order to remove remaining fine foreign matter. The heat treatment may be performed at a temperature of 400 ° C to 1,000 ° C using a rotary dryer as described above. Preferably, the heat treatment may be carried out using a rotary dryer at a temperature of 600 ° C to 800 ° C. Also, the heat treatment may be performed until the water content of the cement binder finally produced becomes less than 3%, preferably, the water content is increased to 0.5% to 3%.

Specifically, the heat treatment according to an embodiment of the present invention may be performed by using a batch dryer to heat-treat at a temperature within the range, thereby lowering the water content and firing, thereby further removing the remaining fine particles.

The rotary dryer may include at least one of a rotating body, a crusher, a heat generator, a speed controller, and a temperature controller.

Here, the rotating body may be one which contains the material to be dried (washed waste concrete fine powder) and rotates together, and the rotating body may be provided with a plurality of fine holes.

The shredding apparatus may further be to shred the agglomerated particles to prevent agglomerated particles while being rotated during the heat treatment.

The heat generating device may be a device that generates heat in the rotating body in accordance with a desired temperature.

The speed regulating device may be configured to regulate the rotational speed of the rotating body, and the temperature regulating device may be a device connected to the heat generating device to regulate heat generation according to the temperature.

The step 4 is a step for preparing a cement binder by separating the sand and cement binder components from the waste concrete fine powder, and the separation may be carried out using a dust collector.

Here, the waste concrete fine powder according to an embodiment of the present invention may include sand and cement binder components, and sand and cement binder may be obtained by separating the sand and the cement binder through the separation. That is, the manufacturing method according to an embodiment of the present invention can be obtained by separating the sand and the cement binder from each other as a result of one manufacturing method, and it is a method of manufacturing a cement binder from waste concrete as desired, And the like.

The dust collector may be connected to the rotary dryer to separate the rotary dryer from the rotary dryer. Alternatively, the dust collector may be separated using a dust collector after the heat treatment using the rotary dryer.

Specifically, the separation may be performed by a particle size difference between the sand and the cement binder using a dust collector. Herein, the dust collector is a device for separating and capturing particles in a dispersion system in which solid or liquid fine particles float in a gas. By separating the fine cement binder from the waste concrete fine powder using the dust collector, The binder can be removed.

The sand may have an average particle size of 0.2 mm to 2 mm, and the cement binder may have an average particle size of 10 μm to 150 μm. Preferably, the sand may have an average particle size of 0.5 mm to 1.5 mm, and the cement binder may have an average particle size of 10 μm to 100 μm.

The dust collector may be a gravity dust collector, an inertial dust collector, a centrifugal dust collector, a filtration dust collector, a cleaning dust collector, or an electrostatic precipitator, but is not limited thereto.

The manufacturing method according to an embodiment of the present invention can produce a cement binder having excellent environmental friendliness and economical efficiency and low foreign matter and easy hydration reaction by using waste concrete as a raw material.

Further, the present invention provides a cement binder produced from the above-mentioned production method.

The cement binder according to an embodiment of the present invention may include silicon dioxide (SiO ₂ ), calcium oxide (CaO), and magnesium oxide (MgO), preferably calcium oxide (CaO) and magnesium oxide ) In an amount of 10% by weight to 50% by weight.

In addition, the cement binder may have a water content of less than 3%. Preferably, the cement binder may have a water content of 0.5% to 3%.

In addition, the cement binder may have a density of 2.0 g / cm < ³ > to 2.5 g / cm < ³ >. Preferably, the cement binder may have a density of 2.1 g / cm < ³ > to 2.4 g / cm < ³ >.

In addition, the cement binder according to an embodiment of the present invention may be used as a curing agent for intermediate treatment of concrete admixture, asphalt filler, solidifying liquor, cement binder additive, embedding agent, migration preventive agent, acid soil conditioner, And preferably used as a solidifying agent such as a solidifying agent for artificial soil, a sewage slurry solidifying agent, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following Examples and Experimental Examples are provided for illustrating the present invention, and the scope of the present invention is not limited by these Examples and Experimental Examples.

Example 1

The waste concrete was pulverized to a powder 3500 cm ² / g using a pulverizer to produce pulverized concrete fine powder, and the pulverized concrete powder was sprayed using a spray screen (water pressure: 2 kg / cm ² ) After that, it was heat-treated at 600 ° C using a rotary dryer and fired. Then, sand and cement binder were separated from fired waste concrete fine powder using a dust collector to obtain a cement binder.

Example 2

The cement binder was obtained in the same manner as in Example 1, except that the water-washing pressure was 4 kg / cm < ² >.

Example 3

The cement binder was obtained in the same manner as in Example 1 except that the coagulant and defoamer were added to the waste concrete before the washing to mix. At this time, the coagulant and defoamer were used in a weight ratio of 1: 1.

Example 4

The cement binder was obtained in the same manner as in Example 1 except that the coagulant and defoamer were added to the waste concrete before the washing to mix. At this time, the coagulant and defoamer were used in a weight ratio of 1: 6.

Comparative Example 1

Waste concrete was pulverized to 3500 cm ² / g using a pulverizer to produce pulverized concrete powder, and calcined at 600 ° C using a rotary dryer. Then, sand and cement binder were separated from fired waste concrete fine powder using a dust collector to obtain a cement binder.

Comparative Example 2

The cement binder was obtained in the same manner as in Example 1 except that the water spraying pressure was 1.5 kg / cm < ² >.

Comparative Example 3

The cement binder was obtained in the same manner as in Example 1, except that the water spraying pressure was 5 kg / cm < ² >.

Comparative Example 4

The cement binder was obtained in the same manner as in Example 1 except that the coagulant and defoamer were added to the waste concrete before the washing to mix. At this time, the coagulant and defoamer were used in a weight ratio of 1: 0.5.

Comparative Example 5

The cement binder was obtained in the same manner as in Example 1 except that the coagulant and defoamer were added to the waste concrete before the washing to mix. At this time, the coagulant and defoamer were used in a weight ratio of 1: 7.

Experimental Example 1

The density, porosity and foreign matter content of each of the cement binders obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were measured based on KS L 5110. At this time, the density was measured by KF F 2314 method, the foreign matter content was measured by KS F 2576 method, and the porosity was measured by BET method. The results are shown in Table 1 below.

division Density (g / cm ³⁾ Porosity (%) Foreign matter content (wt%) Example 1 2.0 48 0.8 Example 2 2.1 50 0.3 Example 3 2.4 42 0.8 Example 4 2.5 30 0.8 Comparative Example 1 1.7 45 10 Comparative Example 2 1.9 46 2.0 Comparative Example 3 2.0 50 0.7 Comparative Example 4 1.8 47 0.8 Comparative Example 5 2.7 20 0.8

As shown in Table 1, the cement binders of Examples 1 to 4 according to one embodiment of the present invention have a porosity of 30% to 50% and a density of 2.0 g / cm ³ to 2.5 g / cm ³ And the content of foreign materials was less than 1.0 wt%.

On the other hand, the cement binder of Comparative Example 2, which is manufactured from the manufacturing method which does not include the cleaning step but which is manufactured from the manufacturing method which includes the cement binder and the cleaning step but is out of the sprinkling pressure range proposed in the present invention, It was confirmed that not only the numerical values out of the proper density range of the proposed cement binder but also the foreign matter contents were up to about 30 times or more. On the other hand, in the case of the cement binder of Comparative Example 3, although the density, the porosity and the foreign matter content showed the physical properties range of the cement binder suggested in the present invention, the water spraying pressure was too high, The yield of the cement binder was remarkably decreased.

In addition, when the density of the cement binder of Comparative Example 4 and Comparative Example 5 produced by using the coagulant and the defoaming agent in a range exceeding the range of the present invention is lowered, or the density and porosity of the cement binder are lower than those of the cement binder The figures showed a remarkable deviation. This indicates that the ratio of the flocculant to the defoamer may be important in order to obtain the physical properties of the desired cement binder.

Experimental Example 2

In order to confirm the applicability of the cement binders prepared in Examples 1 to 4 as a sludge solidifying agent, a sludge solidifying agent containing the cement binder was prepared, and the water reducing effect of the sewage sludge was confirmed. As a comparative example, the effect of reducing the water content of sewage sludge of the sludge solidifying agent containing the cement binder (Comparative Example 6) and the sludge solidifying agent containing the cement binder of Comparative Example 5 was confirmed.

400 parts by weight of a cement binder, a coconut husk material and a bituminous coal material were uniformly mixed with 100 parts by weight of cement to prepare a sludge solidifying agent. At this time, the coconut shell material and the bituminous coal material were used in a weight ratio of 4: 1.

100 parts by weight of sewage sludge having a water content of 85% was mixed with 30 parts by weight of the above sludge solidifying agent and then cured at room temperature until the water content became 60% to prepare respective solidified products.

The change in water content of each of the prepared solid materials (Examples 1 to 4 and Comparative Examples 5 and 6) was measured with time, and the water content change was measured according to the KS F 2306 method. The results are shown in Table 2 below.

division Immediately after mixing (%) After 3 hours curing (%) After 1 day curing (%) After 3 days curing (%) Example 1-1 57.7 49.3 43.8 41 Example 2-1 56.6 48.2 42.5 39.7 Example 3-1 55.7 47.3 41.8 39 Example 4-1 63.2 53.7 47.4 44.2 Comparative Example 5-1 69.8 60.3 55.3 51.8 Comparative Example 6 64.5 54.8 50.8 47.1

As shown in Table 1, in Examples 1 to 4-1 prepared using a sludge solidifying agent containing cement binders of Examples 1 to 4 according to an embodiment of the present invention, The water content of cargoes was found to be effectively reduced over time.

On the other hand, the solidified product of Comparative Example 6 produced by using a sludge solidifying agent not containing a cement binder had only a small effect of decreasing the water content. Comparative Example 5 prepared using the sludge solidifying agent containing the cement binder of Comparative Example 5 -1 was lower than that of the solidified material of Comparative Example 6. This indicates that the porosity of the cement binder of Comparative Example 5 was excessively low, which significantly decreased the porosity of the sludge solidifying agent containing the sludge, thereby reducing the water absorption rate.

Claims (20)

1) crushing waste concrete to produce waste concrete fine powder;
2) adding and mixing at least one of a defoaming agent and a flocculant to waste concrete fine powder;
3) sprinkling the waste concrete fine powder at a high pressure under a pressure of 2 kg / cm ² to 4 kg / cm ² using a spray screen;
4) heat treating the washed waste concrete fine powder; And
5) separating the sand and the cement binder from the waste concrete fine powder after the heat treatment,
Wherein the heat treatment in the step 3) is carried out at a temperature of 400 ° C to 1000 ° C using a rotary dryer, and the coagulant and defoamer are added in a weight ratio of 1: 1 to 6: .
The method according to claim 1,
Wherein the crushing is carried out using at least one apparatus selected from the group consisting of a crusher, a crusher and a crusher in the step (1).
The method according to claim 1,
Wherein the pulverization in the step 1 is such that the powdery degree of the waste concrete is 3,000 cm ² / g or more.
The method according to claim 1,
Wherein the pulverization in the step 1 is such that the powdery degree of waste concrete is from 3,000 cm ² / g to 5,000 cm ² / g.
The method according to claim 1,
Wherein the waste concrete fine powder in the step 1 has an average particle size of from 10 탆 to 2000 탆.
delete delete delete delete delete The method according to claim 1,
Wherein the heat treatment is performed under a temperature condition of 600 ° C to 800 ° C.
The method according to claim 1,
Wherein the heat treatment is performed until the water content becomes less than 3%.
The method according to claim 1,
Wherein the heat treatment is performed until the water content becomes 0.5% to 3%.
The method according to claim 1,
Wherein the separation is performed using a dust collector.
delete delete delete delete delete delete