A production method for producing recycled bricks using construction waste and recycled bricks thereof

Abstract

The application provides a production method for producing regenerated bricks from construction waste and regenerated bricks thereof, and comprises the following steps: storing the construction waste after classification; recovering waste iron through a magnetic separation device to obtain magnetic separation material; gradually crushing the magnetic separation material to obtain crushed material; screening the crushed material to obtain screened material; removing plastic and fiber in the screened material through air separation to obtain air separation material; adding a modifier to the air separation material, mixing, and reacting to obtain modified air separation material; taking the modified air separation material, crushing, adding a mixing liquid, and ball milling to obtain regenerated slurry; and pouring the regenerated slurry into a mold and spraying steam to obtain a finished product. The application can fully utilize the construction waste, has good separation effect, can finely separate particles of various types and various levels, and finally obtains regenerated bricks with good quality, high compressive strength and good thermal insulation performance.

Description

Technical Field

[0001] This invention relates to the field of resource utilization, and in particular to a method for producing recycled bricks from construction waste and the recycled bricks thereof. Background Technology

[0002] Concrete is one of the most widely used civil engineering materials in modern building structures, and it has evolved from a single-performance material to a multi-performance building material. Different types of engineering applications have different requirements for concrete performance, thus leading to the development of various types of concrete. For example, self-compacting concrete has advantages such as good fluidity, short construction period, and low cost, and can well meet the application requirements of complex structural engineering projects.

[0003] With the excessive use of building materials, research on recycled bricks has become a hot topic. This involves manually crushing, washing, and grading waste construction materials to use as aggregates, mixing them with other materials in a specific ratio to partially or completely replace natural aggregates such as sand and gravel. The resulting recycled bricks can then be formulated according to specific processes. Recycled bricks can replace solid clay bricks in load-bearing and non-load-bearing structural parts such as walls. The development and application of recycled bricks in ordinary brick-concrete structures, brick-wood structures, and frame structures not only makes full use of construction waste but also significantly reduces construction costs, aligning with my country's green development philosophy. Summary of the Invention

[0004] Therefore, the purpose of this invention is to propose a production method for producing recycled bricks from construction waste and the recycled bricks thereof, which produce recycled bricks with good mechanical properties and durability, and have significant social and economic benefits.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for producing recycled bricks from construction waste includes the following steps:

[0007] S1 Classification: Construction waste is stored separately according to its type;

[0008] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0009] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0010] S4 screening: Screening the crushed material to obtain screened material;

[0011] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0012] S6 Modification: Add modifier to air-classified material, mix, react, and obtain modified air-classified material;

[0013] S7 slurry: Take modified air-classified material, crush it, add slurry conditioning liquid, ball mill it to obtain regenerated slurry;

[0014] S8 Finished Product: Pour the recycled slurry into a mold and steam it to obtain the finished product.

[0015] To further clarify, the modifier is a silane coupling agent.

[0016] To further explain, the reaction temperature is 60-80℃ and the reaction time is 1-2 hours.

[0017] Further explanation: the slurry comprises the following components by weight: 50-60 parts composite filler, 120-130 parts water, 340-380 parts cement, 25-30 parts sodium hydroxypropyl methylcellulose, 20-30 parts fly ash, 20-30 parts gypsum powder, 25-30 parts slaked lime, 10-15 parts silicate sol, and 20-25 parts sodium silicate.

[0018] To further explain, the slurry comprises the following components by weight: 55 parts composite filler, 125 parts water, 365 parts cement, 28 parts sodium hydroxypropyl methylcellulose, 25 parts fly ash, 25 parts gypsum powder, 28 parts slaked lime, 12 parts silica sol, and 22 parts sodium silicate.

[0019] To further explain, the composite filler is phenolic resin, polyvinyl chloride, polystyrene, and waste plastics.

[0020] To further explain, the steam injection temperature is 160-180℃, and the steam injection time is 1-2 hours.

[0021] To further explain, before pouring into the mold, an alkaline activator is added, which is at least one of Ca(OH)2, Na2SiO3·9H2O, or Na2SO4.

[0022] To further clarify, the amount of the alkaline activator used is 0.5-0.8 w / w.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention, through steps such as classification, magnetic separation, crushing, screening, air separation, modification, and slurry preparation, can fully utilize construction waste as a resource. The sorting effect is good, and particles of different types and grades are separated in a fine manner. The resulting recycled bricks are of good quality, with high compressive strength and good thermal insulation performance.

[0025] This invention adds a slurry to modified air-classified materials, which helps to promote the full hydration of cement and increase the bonding area between aggregates, thereby increasing the bonding force between aggregates and improving the strength of the cement stone that encapsulates the particles after the recycled brick is formed. Ultimately, the compressive strength of the recycled brick can reach more than 31.0 MPa.

[0026] This invention involves sequentially classifying, magnetically separating, crushing, screening, air classifying, modifying, and preparing slurry from construction waste. The resulting recycled slurry is used to formulate recycled bricks, which are then used as building components. These bricks achieve excellent thermal insulation performance, with a heat transfer coefficient K value of 1.132, thus saving energy consumption in buildings. Detailed Implementation

[0027] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0028] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0029] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0030] Example 1

[0031] A method for producing recycled bricks from construction waste includes the following steps:

[0032] S1 Classification: Construction waste is stored separately according to its type;

[0033] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0034] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0035] S4 screening: Screening the crushed material to obtain screened material;

[0036] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0037] S6 modification: Add n-octyltriethoxysilane to the air-classified material, mix, and react at 60°C for 1 hour to obtain the modified air-classified material;

[0038] S7 slurry: Take modified air-classified material, crush it, add slurry (first add composite filler, cement, sodium hydroxypropyl methylcellulose, fly ash, gypsum powder, quicklime, silica sol and sodium silicate and stir for a period of time before adding water), ball mill. If the ball milling time is too long, the slurry will clump together inside; if it is too short, the ball milling will not be sufficient. Here, ball milling is 8 minutes to obtain recycled slurry.

[0039] The slurry consists of: 50 kg of composite filler (phenolic resin, polyvinyl chloride, polystyrene and waste plastic in a mass ratio of 1:1:1:1), 120 kg of water, 340 kg of cement, 25 kg of sodium hydroxypropyl methylcellulose, 20 kg of fly ash, 20 kg of gypsum powder, 25 kg of quicklime, 10 kg of silica sol, and 20 kg of sodium silicate.

[0040] S8 Finished Product: Add 0.5 w / w% alkali activator Ca(OH)2 to the recycled slurry, then pour it into a mold and steam it at 160℃ for 1 hour to obtain the finished product.

[0041] Example 2

[0042] A method for producing recycled bricks from construction waste includes the following steps:

[0043] S1 Classification: Construction waste is stored separately according to its type;

[0044] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0045] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0046] S4 screening: Screening the crushed material to obtain screened material;

[0047] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0048] S6 modification: Add tridecafluoron-octylsilane to the air-classified material, mix, and react at 80°C for 2 hours to obtain the modified air-classified material;

[0049] S7 slurry: Take modified air-classified material, crush it, add slurry (first add composite filler, cement, sodium hydroxypropyl methylcellulose, fly ash, gypsum powder, quicklime, silica sol and sodium silicate and stir for a period of time before adding water), ball mill. If the ball milling time is too long, the slurry will clump together inside; if it is too short, the ball milling will not be sufficient. Here, ball milling is 8 minutes to obtain recycled slurry.

[0050] The slurry consists of: 60 kg of composite filler (phenolic resin, polyvinyl chloride, polystyrene and waste plastic in a mass ratio of 1:1:1:1), 130 kg of water, 380 kg of cement, 30 kg of sodium hydroxypropyl methylcellulose, 20 kg of fly ash, 30 kg of gypsum powder, 30 kg of quicklime, 15 kg of silica sol, and 25 kg of sodium silicate.

[0051] S8 Finished Product: Add 0.8 w / w% alkali activator Na2SiO3·9H2O to the recycled slurry, then pour it into a mold and steam it at 180℃ for 2 hours to obtain the finished product.

[0052] Example 3

[0053] A method for producing recycled bricks from construction waste includes the following steps:

[0054] S1 Classification: Construction waste is stored separately according to its type;

[0055] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0056] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0057] S4 screening: Screening the crushed material to obtain screened material;

[0058] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0059] S6 modification: Add n-octyltriethoxysilane to the air-classified material, mix, and react at 70°C for 1.5 h to obtain the modified air-classified material;

[0060] S7 slurry: Take modified air-classified material, crush it, add slurry (first add composite filler, cement, sodium hydroxypropyl methylcellulose, fly ash, gypsum powder, quicklime, silica sol and sodium silicate and stir for a period of time before adding water), ball mill. If the ball milling time is too long, the slurry will clump together inside; if it is too short, the ball milling will not be sufficient. Here, ball milling is 8 minutes to obtain recycled slurry.

[0061] The slurry consists of: 55 kg of composite filler (phenolic resin, polyvinyl chloride, polystyrene and waste plastic in a mass ratio of 1:1:1:1), 125 kg of water, 365 kg of cement, 28 kg of sodium hydroxypropyl methylcellulose, 25 kg of fly ash, 25 kg of gypsum powder, 28 kg of quicklime, 12 kg of silica sol, and 22 kg of sodium silicate.

[0062] S8 Finished Product: Add 0.7 w / w% alkali activator Ca(OH)2 to the recycled slurry, then pour it into a mold and steam at 170℃ for 1.5 hours to obtain the finished product.

[0063] I. Compressive Strength of Recycled Bricks

[0064] The finished products obtained in Examples 1-3 above are recycled bricks. After demolding, they are cured in a standard curing room for 7 days and then moved outside for natural curing for 28 days. The compressive strength of the recycled bricks is determined according to the "Standard for Test Methods of Basic Mechanical Properties of Masonry" (GB / T50129-2011). The specimen size is 150mm×150mm×50mm. The results are shown in Table 1 below.

[0065] Table 1 Compressive strength of recycled bricks

[0066] project Example 1 Example 2 Example 3 Compressive strength (MPa) 31.0 31.7 33.3

[0067] As shown in Table 1 above, the compressive strength of the recycled bricks obtained in Examples 1-3 ranges from 31.0 to 33.3 MPa. Through steps such as classification, magnetic separation, crushing, screening, air separation, modification, slurry preparation, and finished product preparation, construction waste can be fully utilized as a resource. The sorting effect is good, and particles of different types and grades are separated finely. At the same time, the addition of slurry to the modified air-separated material promotes the full hydration of cement and increases the bonding area between aggregates, thereby increasing the bonding force and improving the strength of the cement stone that encapsulates the particles after the recycled bricks are formed. The final recycled bricks are of good quality, with a compressive strength of over 31.0 MPa.

[0068] Comparative Example 1

[0069] A method for producing recycled bricks from construction waste includes the following steps:

[0070] S1 Classification: Construction waste is stored separately according to its type;

[0071] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0072] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0073] S4 screening: Screening the crushed material to obtain screened material;

[0074] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0075] S6 modification: Add tridecafluoron-octylsilane to the air-classified material, mix, and react at 70°C for 1.5 h to obtain the modified air-classified material;

[0076] S7 slurry: Take modified air-classified material, crush it, add slurry (first add composite filler, cement, sodium hydroxypropyl methylcellulose, fly ash, gypsum powder, quicklime, silica sol and sodium silicate and stir for a period of time before adding water), ball mill. If the ball milling time is too long, the slurry will clump together inside; if it is too short, the ball milling will not be sufficient. Here, ball milling is 8 minutes to obtain recycled slurry.

[0077] The slurry consists of: 55 kg of composite filler (epoxy resin and waste rubber in a mass ratio of 1:1), 125 kg of water, 365 kg of cement, 28 kg of lignocellulose, 25 kg of fly ash, 25 kg of gypsum powder, 28 kg of quicklime, 12 kg of silica fume, and 22 kg of calcium phosphate.

[0078] S8 Finished Product: Add 0.7 w / w% alkali activator Ca(OH)2 to the recycled slurry, then pour it into a mold and steam at 170℃ for 1.5 hours to obtain the finished product.

[0079] After testing, the compressive strength of the recycled brick in Comparative Example 1 was 18.8 MPa.

[0080] II. Thermal Insulation Performance of Recycled Bricks

[0081] According to the "Standard for Energy Conservation Inspection of Heating Residential Buildings" (JGJ132-2001), the heat transfer coefficient of the recycled brick wall was determined using the JW-1 wall insulation performance testing device. A 10mm thick mortar layer was applied to the wall, resulting in a total wall thickness of 280mm. The wall was plastered one day after construction and left to stand naturally for seven days. Five measuring points were then taken on the wall for testing. The calculation formula is as follows:

[0082] R = ΔT / (C × E), where R is the thermal resistance of the specimen itself, m 2 ·K / W, △T is the temperature difference between the hot and cold surfaces of the specimen, °C, C is the calibration coefficient of the heat flow meter, W / m 2 ·mv, where E is the electromotive force, mv.

[0083] K = 1 / (R + R) i +R o In the formula, K is the heat transfer coefficient, W / m 2 K and R represent the thermal resistance of the specimen itself, and R represents the thermal resistance of the specimen itself. i The heat transfer resistance of the inner surface of the specimen, m 2 ·K / W, R o The heat transfer resistance m of the outer surface of the specimen 2 ·K / W.

[0084] Comparative Example 2

[0085] A method for producing recycled bricks from construction waste includes the following steps:

[0086] S1 Classification: Construction waste is stored separately according to its type;

[0087] S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials;

[0088] S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material;

[0089] S4 screening: Screening the crushed material to obtain screened material;

[0090] S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material.

[0091] S6 Crushing: Further crush the air-separated material to a particle size of 1cm to obtain crushed construction waste;

[0092] S7 slurry: Take crushed construction waste, add 125 kg of water, 365 kg of cement, 50 kg of silica fume, 55 kg of 20 mm long polypropylene fiber and 10 kg of sodium dodecylbenzene sulfonate, stir evenly, then add 50 kg of sepiolite, 20 kg of sodium carboxymethyl cellulose, 12 kg of sodium butylnaphthalene sulfonate and 40 kg of n-octyltriethoxysilane, stir to obtain recycled slurry;

[0093] S8 Finished Product: Pour the recycled slurry into a mold and steam it at 170°C for 1.5 hours to obtain the finished product.

[0094] The results of the above measurements are shown in Table 2 below.

[0095] Table 2 Heat transfer coefficients of recycled brick walls

[0096]

[0097] The heat transfer coefficient K represents the amount of heat transferred through a 1-square-meter area in 1 second when the air temperature difference between the two sides of the building envelope is 1 degree (K, ℃) under steady heat transfer conditions. The lower the K value, the better the thermal insulation performance of the wall.

[0098] As shown in Table 2, the recycled brick wall obtained by this invention has good thermal insulation performance. By sorting, magnetically separating, crushing, screening, air classifying, modifying, and preparing slurry from construction waste, the obtained recycled slurry is used to prepare recycled bricks, which are then used as maintenance components. This results in good thermal insulation performance and helps save energy consumption in buildings.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing recycled bricks from construction waste, characterized in that, Includes the following steps: S1 Classification: Construction waste is stored separately according to its type; S2 Magnetic Separation: The stored construction waste is passed through a magnetic separation device to recover scrap iron and obtain magnetically separated materials; S3 Crushing: The magnetically separated material is gradually crushed to obtain crushed material; S4 screening: Screening the crushed material to obtain screened material; S5 air classifier: The screened material is air-classified to remove plastics and fibers from the material, resulting in air-classified material. S6 Modification: Add a modifier to the air-classified material, mix, and react to obtain modified air-classified material; the modifier is a silane coupling agent, the reaction temperature is 60-80℃, and the reaction time is 1-2 hours; S7 Slurry: Take modified air-classified material, crush it, add slurry conditioning liquid, ball mill it to obtain recycled slurry; the slurry conditioning liquid is composed of the following weight components: 50-60 parts composite filler, 120-130 parts water, 340-380 parts cement, 25-30 parts sodium hydroxypropyl methylcellulose, 20-30 parts fly ash, 20-30 parts gypsum powder, 25-30 parts hydrated lime, 10-15 parts silicate sol, and 20-25 parts sodium silicate. S8 Finished Product: The recycled slurry is poured into a mold and steamed to obtain the finished product. The steaming temperature is 160-180℃ and the steaming time is 1-2 hours. Before pouring into the mold, 0.5-0.8 w / w% of an alkaline activator is added. The alkaline activator is at least one of Ca(OH)2, Na2SiO3·9H2O or Na2SO4. The composite filler is composed of phenolic resin, polyvinyl chloride, polystyrene, and waste plastics.

2. A method for producing recycled bricks from construction waste according to claim 1, characterized in that, The slurry is composed of the following components by weight: 55 parts composite filler, 125 parts water, 365 parts cement, 28 parts sodium hydroxypropyl methylcellulose, 25 parts fly ash, 25 parts gypsum powder, 28 parts slaked lime, 12 parts silica sol, and 22 parts sodium silicate.

3. Recycled bricks prepared by the production method of producing recycled bricks from construction waste according to any one of claims 1 to 2.

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