Process for producing concrete using construction waste

Abstract

The application provides a process for producing concrete by recycling construction waste, and belongs to the technical field of concrete recycling, and comprises primary crushing, primary screening, secondary crushing, secondary screening, aggregate modification and configuration. In the aggregate modification, high-temperature calcination is used to separate the aggregate from the cement slurry, thereby improving the purity of the aggregate. Meanwhile, a gaseous reducing agent is introduced into the calcination furnace, and the high temperature of the calcination is used to make the gaseous reducing agent react with the rust in the material to generate elemental iron and carbon dioxide. The carbon dioxide is directly discharged during the calcination process, and the elemental iron has magnetism. Subsequently, an iron remover is used to remove the reduced elemental iron, thereby achieving the purpose of removing the rust in the material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of concrete recycling, and particularly relates to a process for producing concrete by recycling construction waste. BACKGROUND

[0002] The construction waste recycled concrete is a new type of concrete prepared by treating the waste concrete in construction waste and mixing different grades of aggregates in proportion to replace natural aggregates partially or wholly, is a building material with wide application prospect and environmental protection significance, and can provide high-quality building materials for building engineering by reasonably utilizing the waste concrete in construction waste, thereby reducing resource waste and environmental pollution.

[0003] The production process of the recycled concrete comprises the steps of recycling, crushing, impurity removal and grade division of the waste concrete blocks, and finally adding cement, water and the like to prepare new concrete, but in the construction process, steel bars are usually implanted in the concrete during concrete pouring to increase the strength of the concrete pouring part, and rust is generated on the surface of the steel bars, which leads to the adhesion of non-magnetic rust (iron oxide) on the surface of the recycled construction waste, and the rust is difficult to remove, and after the recycled concrete is prepared, the iron oxide changes the performance of the concrete and cannot meet the use requirement. SUMMARY

[0004] In view of the above problems, the application provides a process for producing concrete by recycling construction waste, which at least partially solves the above problems.

[0005] The technical scheme adopted by the application is as follows: the application provides a process for producing concrete by recycling construction waste, which comprises the following steps:

[0006] S1: material crushing, crushing the construction waste;

[0007] S2: material screening, conveying the material obtained in the step S1 to a horizontal screen for screening to obtain four grades of aggregates with particle sizes of 0-5.0 mm, 5.0-10.0 mm, 10.0-31.0 mm and greater than 31.0 mm, and the aggregate with a particle size greater than 31.0 mm is returned to the step S1 for crushing;

[0008] S3: aggregate modification, calcining the aggregates with particle sizes of 5.0-10.0 mm and 10.0-31.0 mm in the step S4 to separate the aggregates from the cement slurry;

[0009] S4: configuration, the weight parts of the particle size is 10.0-31.0mm coarse aggregate 500-600 parts, particle size is 5.0-10.0mm fine aggregate 400-500 parts, cement 150-200 parts, fly ash 60-180 parts, silica fume 15-30 parts, basalt-carbon fiber 30-40 parts, water reducing agent 10-20 parts, air entraining agent 3-10 parts and water 180-250 parts are mixed uniformly to obtain recycled concrete;

[0010] Wherein, in the S3, the gas reducing agent is introduced into the calcining furnace, and the content of the gas reducing agent in the air in the calcining furnace is greater than 95%, and the calcining temperature is 800-850 DEG C, and the calcining time is 1.0-3.0h.

[0011] Further, in the S2, a negative pressure air separator is arranged, which is arranged above the horizontal screen in the S2, and the light substances in the raw materials are removed by negative pressure adsorption while screening.

[0012] Further, in the S2, a specific gravity screen is arranged, which is arranged at the output end of the horizontal screen, and the particle size of the material screened by the horizontal screen is 5.0-10.0mm, and the 10.0-31.0mm aggregate is transported to the specific gravity screen for purification.

[0013] Further, in the S3, a three-stage iron remover is arranged, and the aggregate in the S3 is calcined and cooled sufficiently, and then is transported to the three-stage iron remover by a conveying belt to remove the iron reduced by the gas reducing agent in the calcining process.

[0014] Further, the S1 comprises the following steps:

[0015] S1.1: primary crushing, the construction waste is put into a coarse crusher for primary coarse crushing;

[0016] S1.2: primary screening, the material obtained in the S1.1 is transported to a heavy tension screen to remove the surface slag, and then is transported to a manual picking table for sorting of sundries;

[0017] S1.3: secondary crushing, the material obtained in the S1.2 is put into a fine crusher for secondary fine crushing.

[0018] Further, a stock bin and a vibrating feeder are arranged in the S1.1, the vibrating feeder is arranged at the bottom discharge port of the stock bin, and the vibrating feeder uniformly feeds the crusher in the S1.1.

[0019] Further, a bar grate pre-screen is arranged in the S1.1, which is arranged at the bottom of the vibrating feeder, and can pre-screen the material smaller than 100.0mm while the vibrating feeder vibrates and feeds.

[0020] Further, a first-stage iron remover is arranged in the S1.1, and the first-stage iron remover is arranged at the output end of the coarse crusher, and the material output by the coarse crusher is conveyed to the first-stage iron remover by a conveying belt, and the first-stage iron remover removes the iron.

[0021] Further, a second-stage iron remover is arranged in the S1.3, and the second-stage iron remover is arranged at the output end of the fine crusher, and the material output by the fine crusher is conveyed to the second-stage iron remover by a conveying belt, and the second-stage iron remover removes the iron.

[0022] Further, a positive pressure air separator is arranged in the S1.2, and the positive pressure air separator is arranged at the output end of the heavy type tension screen in the S1.2, and the positive pressure air separator removes the light substance in the raw material in a positive pressure blowing mode.

[0023] The application has the following beneficial effects by using the above structure:

[0024] The high-temperature calcination is used to separate the aggregate from the cement paste, and the purity of the aggregate is improved, meanwhile, the gas reducing agent is introduced into the calcination furnace, and the high temperature of the calcination is used to make the gas reducing agent react with the rust (Fe2O3) in the material to generate iron single substance, and the iron single substance has magnetism, and the iron single substance removed by the iron remover in the subsequent process, so that the rust (Fe2O3) in the material is removed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A process flow chart for producing concrete by using construction waste is provided for the embodiment of the application.

[0026] The accompanying drawings are used to provide further understanding of the application, and constitute a part of the specification, and are used to explain the application together with the embodiments of the application, and do not constitute a limitation on the application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application, obviously, the described embodiments are only part of the embodiments of the application, but not all the embodiments of the application; based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0028] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, an embodiment of the present invention proposes a process for producing concrete by recycling construction waste, including the following steps:

[0031] S1: material crushing;

[0032] S1.1: Primary crushing: put the construction waste into the coarse crusher for primary coarse crushing.

[0033] In an optional embodiment, the coarse crusher is a jaw crusher, which has a large crushing ratio and can process large pieces of construction waste.

[0034] Furthermore, in S1.1, a hopper and a vibrating feeder are provided at the feed port of the jaw crusher. The vibrating feeder is arranged at the bottom discharge port of the hopper. The vibrating feeder feeds the jaw crusher at a uniform speed to maintain the crushing efficiency of the jaw crusher and avoid the phenomenon of material piling or material shortage caused by manual feeding.

[0035] Furthermore, a grate pre-screen is provided in S1.1. The grate pre-screen is arranged at the bottom of the vibrating feeder. While the vibrating feeder is vibrating and feeding, the vibration of the vibrating feeder is used to allow materials smaller than 100.0MM to pass through the grate pre-screen and be pre-screened, while materials larger than 100.0MM are fed into the jaw crusher, thereby improving the crushing efficiency of the jaw crusher. The materials crushed by the jaw crusher and the materials under the grate pre-screen are collected and transported.

[0036] Furthermore, a first-stage iron remover is provided in S1.1. The first-stage iron remover is set at the output end of the coarse crusher. The material crushed by the jaw crusher is combined with the material under the grate pre-screen, and then transported to the first-stage iron remover through a conveyor belt. The first-stage iron remover removes the iron waste in the material and improves the purity of the material.

[0037] S1.2: First-stage screening: the material obtained in S1.1 is conveyed to a heavy-duty relaxation screen to remove the surface debris, and then conveyed to a manual picking platform for debris sorting.

[0038] The heavy-duty flip-flow screen can make the material to be screened thoroughly loose and quickly separated by high acceleration, so as to effectively remove the slag on the surface of the material and improve the purity of the material.

[0039] Further, a positive pressure air separator is arranged in S1.2, the positive pressure air separator is arranged at the output end of the heavy-duty flip-flow screen in S1.2, the screened material (aggregate) after the screening of the heavy-duty flip-flow screen is conveyed into the positive pressure air separator, a positive pressure is formed in the positive pressure air separator, the material enters the positive pressure air separator along the airflow direction, and the material is subjected to a strong airflow force and is separated or sorted under the action of the high-speed rotating separating wheel. Light impurities or dust and other lighter substances are taken away by the airflow, and the heavier material is discharged along the set path.

[0040] After the material is air separated by the positive pressure air separator, the material is conveyed to the manual picking table, and the impurities are manually sorted, the large impurities which are difficult to be removed by air separation are removed, and the purity of the material is improved.

[0041] S1.3: Secondary crushing, the material obtained in S1.2 is put into a fine crusher for secondary fine crushing.

[0042] In an optional embodiment, the fine crusher is a impact crusher, the impact crusher can flexibly adjust the discharge particle size by adjusting the rotor speed, the gap between the impact plate and the grinding cavity, so that the material after the first crushing is subjected to the secondary crushing, the particle size of the material is further reduced, and the particle size of the crushed material meets the requirements by adjusting the discharge particle size of the impact crusher.

[0043] Further, a secondary iron separator is arranged in S1.3, the secondary iron separator is arranged at the output end of the fine crusher, the material output by the fine crusher is conveyed to the secondary iron separator by a conveying belt, and the iron in the material is removed by the secondary iron separator.

[0044] S2: Material screening, the material obtained in S1.3 is conveyed to a horizontal screen for screening, the horizontal screen is provided with three levels of screen meshes, the mesh number gradually increases from top to bottom, the material is first conveyed to the uppermost screen mesh of the horizontal screen, and then is screened downward level by level, four levels of aggregates with particle sizes of 0-5.0 mm, 5.0-10.0 mm, 10.0-31.0 mm and greater than 31.0 mm can be obtained by the screening of the three levels of screen meshes, the aggregate greater than 31.0 mm is returned to the fine crusher in S1.3 for re-crushing, and the aggregate with a particle size of 0-5.0 mm is conveyed to a humidifier, is humidified and mixed uniformly by the humidifier, and is then conveyed to a finished product warehouse for storage.

[0045] Further, a negative pressure air separator is arranged in S2, and the negative pressure air separator is arranged at the uppermost screen of the horizontal screen in S2. The material is first transported to the uppermost screen of the horizontal screen for screening. Under the vibration of the horizontal screen, the material is uniformly dispersed on the screen. At this time, the light material in the raw material is removed by using the negative pressure adsorption method, and the purity of the material is further improved.

[0046] Further, a specific gravity screen is arranged in S2, and the specific gravity screen is arranged at the output end of the horizontal screen. The particle size of the material screened by the horizontal screen is 5.0-10.0 mm and 10.0-31.0 mm, and the aggregate is transported into the specific gravity screen for purification.

[0047] The specific gravity screen utilizes the difference in specific gravity of the material. Under the action of the airflow blowing on the vibrating screen surface, the materials with different specific gravities produce different motion trajectories, thereby realizing automatic classification. Specifically, the material with large specific gravity can pass through the screen hole, and the material with small specific gravity is blocked by the screen. The light material in the material is removed by using the specific gravity screen, and the purity of the material is improved.

[0048] Further, a cleaning device is arranged in S2, and the cleaning device is arranged at the output end of the specific gravity screen. The particle size of the aggregate output by the specific gravity screen is 5.0-10.0 mm and 10.0-31.0 mm, and the aggregate is transported into the cleaning device for cleaning, thereby improving the cleanliness of the material.

[0049] S3: Aggregate modification. The aggregate with a particle size of 5.0-10.0 mm and 10.0-31.0 mm in S2 is calcined to separate the aggregate from the cement slurry. The separated cement is ground, and then transported to the finished product bin. The dehydrated cement slurry has water activation performance after being sufficiently ground, and can be used to prepare a recycled cementitious material.

[0050] Further, in the calcination process, a gaseous reducing agent is continuously introduced into the calcination furnace, and the content of the gaseous reducing agent in the air in the calcination furnace is always greater than 95%. The calcination temperature is 800-850°C, and the calcination time is 1.0-3.0 h. In the high-temperature state, the gaseous reducing agent is used to reduce the iron rust (Fe2O3) in the material into iron single element, and the iron single element has magnetism.

[0051] A horizontal screen is also arranged in S3. After the calcined material is sufficiently cooled, the material is transported to the horizontal screen, and the material with a particle size of 0-5.0 mm (calcined and separated cement), 5.0-10.0 mm, and 10.0-31.0 mm can be obtained.

[0052] Further, a three-stage iron remover is arranged in S3. The screened material is transported to the three-stage iron remover by the conveying belt, the iron single element reduced by the gaseous reducing agent in the calcination process is removed, and then the material is transported to the bin for storage.

[0053] In a specific embodiment, the gaseous reducing agent is carbon monoxide (CO), and carbon monoxide (CO) and iron oxide (Fe2O3) generate iron and carbon dioxide (3CO+Fe2O3—2Fe+3CO2) at high temperature.

[0054] In this way, the aggregate is separated from the cement slurry by high-temperature calcination, improving the purity of the aggregate. At the same time, a gaseous reducing agent (CO) is introduced into the calcination furnace, and the gaseous reducing agent (CO) reacts with the rust (Fe2O3) in the material at high temperature generated by calcination to generate iron and carbon dioxide (CO2). Carbon dioxide (CO2) is directly discharged during the calcination process, and iron has magnetic properties. The reduced iron is removed by an iron remover, thereby achieving the purpose of removing rust (Fe2O3) from the material.

[0055] S4: Configuration, 500-600 parts of coarse aggregate with a particle size of 10.0-31.0 mm, 400-500 parts of fine aggregate with a particle size of 5.0-10.0 mm, 150-200 parts of cement, 60-180 parts of fly ash, 15-30 parts of silica fume, 30-40 parts of basalt-carbon fiber, 10-20 parts of water reducing agent, 3-10 parts of air entraining agent, and 180-250 parts of water are uniformly mixed to obtain recycled concrete.

[0056] The following is the performance verification data of the recycled concrete after removing rust, and the performance of the recycled concrete without removing rust is compared.

[0057]

[0058] Detailed steps of the embodiment:

[0059] S1: Material crushing

[0060] S1.1, the construction waste is put into the stock bin, and the uniform speed is fed to the jaw crusher through the vibrating feeder. While the vibrating feeder is vibrating, the material smaller than 100.0MM can pass through the grate pre-screening, and the material larger than 100.0MM is sent into the jaw crusher. The crushed material and the pre-screened material are collected and transported;

[0061] The crushed material and the pre-screened material are collected and then transported to the first iron remover by the conveyor belt. The first iron remover removes the iron waste in the material, improving the purity of the material;

[0062] S1.2, the material obtained in S1.1 is transported to the heavy vibrating screen to remove the surface slag;

[0063] The oversize (aggregate) after the heavy trommel screen screening is transported into the positive pressure air separator, and a positive pressure is formed inside the positive pressure air separator. The material enters the positive pressure air separator along the airflow direction. In the positive pressure air separator, the material is subjected to strong airflow force and is separated or sorted under the action of the high-speed rotating separating wheel. Light impurities or dust and other lighter substances are carried away by the airflow, and heavier materials are discharged along the set path.

[0064] After the material is air separated by the positive pressure air separator, it is transported to the manual picking table for manual sorting of impurities, removal of large impurities that are difficult to remove by air separation, and improvement of the purity of the material.

[0065] S1.3. The material obtained in S1.2 is transported to the impact crusher for further crushing to reduce the particle size of the material, and the particle size of the crushed material is adjusted to meet the requirements.

[0066] The material output by the impact crusher is transported to the secondary iron separator by the conveyor belt for iron removal to further reduce the iron content in the material.

[0067] S2: Secondary screening

[0068] S2.1. The material obtained in S1 is transported to the horizontal screen for screening. The horizontal screen is provided with three levels of screen meshes, and the mesh size increases from top to bottom. The material is first transported to the uppermost screen mesh of the horizontal screen, and then is screened downward step by step. The four levels of aggregate with particle sizes of 0-5.0 mm, 5.0-10.0 mm, 10.0-31.0 mm, and greater than 31.0 mm are obtained by the three levels of screen meshes. The aggregate with a particle size greater than 31.0 mm is returned to the fine crusher in S1.3 for re-crushing. The aggregate with a particle size of 0-5.0 mm is transported to the humidifier, mixed uniformly by the humidifier, and then transported to the finished product storage.

[0069] S2.2. During screening, the material is first transported to the uppermost screen mesh of the horizontal screen for screening. Under the vibration of the horizontal screen, the material is uniformly dispersed on the screen mesh. At this time, the negative pressure air separator is used to remove light substances in the raw material to further improve the purity of the material.

[0070] S2.3. The aggregate with particle sizes of 5.0-10.0 mm and 10.0-31.0 mm obtained by the horizontal screen screening is transported to the specific gravity screen for purification.

[0071] S2.4. The aggregate with particle sizes of 5.0-10.0 mm and 10.0-31.0 mm output by the specific gravity screen is transported to the cleaning equipment for cleaning to improve the cleanliness of the material.

[0072] S3: Aggregate modification

[0073] S3.1, calcining the aggregate with particle size of 5.0-10.0 mm and 10.0-31.0 mm in S2 to separate the aggregate from the cement slurry, continuously feeding the gaseous reducing agent (CO) into the calcining furnace, and keeping the content of the gaseous reducing agent in the air in the calcining furnace greater than 95%, the calcining temperature being 800-850℃, and the calcining time being 1.0-3.0 h, and under the high temperature, the gaseous reducing agent is used to reduce the iron rust (Fe2O3) in the material into iron element, and the iron element has magnetism;

[0074] S3.2, after the aggregate is calcined in the environment of the gaseous reducing agent and is sufficiently cooled, the aggregate is transported to a horizontal screen for screening, and the aggregate with particle size of 0-5.0 mm, 5.0-10.0 mm and 10.0-31.0 mm can be obtained;

[0075] S3.3, the aggregate with particle size of 0-5.0 mm, 5.0-10.0 mm and 10.0-31.0 mm output from the horizontal screen is transported by the conveying belt to the three-stage iron remover respectively, to remove the iron element reduced by the gaseous reducing agent in the calcining process, so as to remove the iron rust (Fe2O3) in the material;

[0076] S3.4, the aggregate with particle size of 0-5.0 mm (cement slurry separated by calcining) after the iron removal is transported to a grinding machine, and after being sufficiently ground, is transported to a finished product warehouse for storage;

[0077] S3.5, the aggregate with particle size of 5.0-10.0 mm and 10.0-31.0 mm after the iron removal is transported to the finished product warehouse for storage;

[0078] S4: configuring, uniformly mixing 500-600 parts by weight of the coarse aggregate with particle size of 10.0-31.0 mm, 400-500 parts by weight of the fine aggregate with particle size of 5.0-10.0 mm, 150-200 parts by weight of cement, 60-180 parts by weight of fly ash, 15-30 parts by weight of silica fume, 30-40 parts by weight of basalt-carbon fiber, 10-20 parts by weight of water reducing agent, 3-10 parts by weight of air entraining agent, and 180-250 parts by weight of water, to obtain the recycled concrete.

[0079] Example 2

[0080] In this example, the gaseous reducing agent in step S3.1 is replaced by ammonia gas (NH3), and other conditions are the same as those in Example 1.

[0081] The 5.0-10.0mm, 10.0-31.0mm aggregate in S2 is calcined to separate the aggregate from the cement paste, and a gaseous reducing agent (NH3) is continuously introduced into the calcining furnace, and the content of the gaseous reducing agent in the air in the calcining furnace is always greater than 95%, and the calcining temperature is 800-850℃, and the calcining time is 1.0-3.0h, and in the high temperature state, the gaseous reducing agent is used to reduce the iron rust (Fe2O3) in the material into iron single element, and nitrogen gas (N2) and water (H2O) are generated.

[0082] In the embodiment, the gaseous reducing agent (NH3) reduces the iron rust (Fe2O3) into iron single element in the high temperature environment, and nitrogen gas (N2) and water (H2O) are generated, the water (H2O) is evaporated by the high temperature, and the nitrogen gas (N2) can be used as a protective gas in the reduction process.

[0083] In combination with the above embodiments: the aggregate is separated from the cement paste by high temperature calcination to improve the purity of the aggregate, and the gaseous reducing agent is introduced into the calcining furnace, and the gaseous reducing agent reacts with the iron rust (Fe2O3) in the material by the high temperature of calcination to generate iron single element, and the iron single element has magnetism, and the reduced iron single element is removed by a de-ironing device, thereby achieving the purpose of removing the iron rust (Fe2O3) in the material.

[0084] It should be noted that the relational terms herein such as first and second and the like are used only to differentiate one entity or operation from another, and do not necessarily require or imply that any such actual relationship or order exists between or among the entities or operations. Also, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles, or devices that include a series of elements not only include those elements, but also include other elements not explicitly listed or other elements inherent to such processes, methods, articles, or devices.

[0085] The above describes the present application and its embodiments, which are not limited, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired thereby, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solution can be designed, which should belong to the protection scope of the present application.

Claims

1. A process for producing concrete from construction waste, characterized in that, The method comprises the following steps: S1: material crushing, crushing construction waste; S2: material screening, conveying the material obtained in S1 to a horizontal screen for screening, obtaining four grades of aggregate with particle sizes of 0-5.0 mm, 5.0-10.0 mm, 10.0-31.0 mm, and greater than 31.0 mm, and returning the aggregate greater than 31.0 mm to S1 for crushing; S3: aggregate modification, calcining the aggregate with particle sizes of 5.0-10.0 mm and 10.0-31.0 mm obtained in S2 to separate the aggregate from cement slurry; S4: configuration, uniformly mixing 500-600 parts of coarse aggregate with a particle size of 10.0-31.0 mm, 400-500 parts of fine aggregate with a particle size of 5.0-10.0 mm, 150-200 parts of cement, 60-180 parts of fly ash, 15-30 parts of silica ash, 30-40 parts of basalt-carbon fiber, 10-20 parts of water reducing agent, 3-10 parts of air entraining agent, and 180-250 parts of water to obtain recycled concrete; In S3, a gaseous reducing agent is introduced into the calcining furnace, the content of the gaseous reducing agent in the air in the calcining furnace is greater than 95%, the calcining temperature is 800-850°C, and the calcining time is 1.0-3.0 h; In S3, a three-stage iron remover is arranged, the aggregate in S3 is calcined and fully cooled, then conveyed to the three-stage iron remover by a conveying belt, and the iron reduced by the gaseous reducing agent in the calcining process is removed.

2. Process for the production of concrete from recycled construction waste according to claim 1, characterized in that: In S2, a negative pressure air separator is arranged above the horizontal screen in S2, and the light substances in the raw material are removed by negative pressure adsorption while screening.

3. Process for the production of concrete from recycled construction waste according to claim 1, characterized in that: In S2, a specific gravity screen is arranged at the output end of the horizontal screen, and the aggregate with particle sizes of 5.0-10.0 mm and 10.0-31.0 mm screened by the horizontal screen is conveyed into the specific gravity screen for purification.

4. The process for the production of concrete from recycled construction waste according to claim 1, characterized in that: S1 comprises the following steps: S1.1: primary crushing, feeding the construction waste into a coarse crusher for primary coarse crushing; S1.2: primary screening, conveying the material obtained in S1.1 to a heavy trommel screen to remove the surface dirt of the material, and then conveying the material to a manual picking table for sorting of sundries; S1.3: secondary crushing, feeding the material obtained in S1.2 into a fine crusher for secondary fine crushing.

5. Process for the production of concrete from recycled construction waste according to claim 4, characterized in that: In S1.1, a stock bin and a vibrating feeder are arranged, the vibrating feeder is arranged at the bottom discharge port of the stock bin, and the vibrating feeder uniformly feeds the crusher in S1.

1.

6. Process for the production of concrete from recycled construction waste according to claim 5, characterized in that: In S1.1, a grate pre-screen is arranged at the bottom of the vibrating feeder, and the grate pre-screen can pre-screen the material smaller than 100.0 mm while the vibrating feeder is vibrating and feeding.

7. Process for the production of concrete from recycled construction waste according to claim 4, characterized in that: In S1.1, a primary iron remover is arranged at the output end of the coarse crusher, and the material output by the coarse crusher is conveyed to the primary iron remover by a conveying belt, and the iron is removed by the primary iron remover.

8. The process for the production of concrete from construction waste according to claim 4, characterized in that: In the S1.3, a secondary iron remover is arranged at the output end of the fine crusher, and the material output by the fine crusher is conveyed to the secondary iron remover by a conveying belt, and the secondary iron remover removes iron.

9. Process for the production of concrete from recycled construction waste according to claim 4, characterized in that: In the S1.2, a positive pressure air separator is arranged at the output end of the heavy type tension screen in the S1.2, and the positive pressure blowing mode is adopted to remove light substances in the raw materials.

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