A stirring kettle, aerated concrete block recycled from construction waste, and preparation method and application thereof

Abstract

The present invention provides a stirring kettle, aerated concrete blocks recycled from construction waste, and a preparation method and application thereof, and belongs to the technical field of resource utilization of construction waste. The stirring kettle provided by the present invention comprises a stirring kettle body, a stirring module, an air pressure sensor (1), an air inlet pipe valve (2), a liquid material pipe valve (3), a powder material pipe valve (5), and a discharge pipe valve (13); wherein the shell of the stirring kettle body is a sandwich structure, comprising an inner wall (9) of the stirring kettle and an outer shell (11) of the stirring kettle, a plurality of vents are arranged on the inner wall (9) of the stirring kettle, and a molecular sieve film (10) is arranged between the inner wall (9) of the stirring kettle and the outer shell (11). By using the stirring kettle mixing provided by the present invention, it is possible to prepare recycled aerated concrete blocks using construction waste as the main raw material without using a foaming agent, and in particular, it is possible to use a large amount of waste aerated concrete blocks, thereby realizing resource disposal thereof.

Description

Technical Field

[0001] The invention relates to the technical field of resource utilization of construction waste, and in particular to a stirring kettle, a construction waste recycled aerated concrete block, and a preparation method and application thereof. Background Art

[0002] Aerated concrete blocks have become a new type of wall material that is vigorously promoted in my country due to their light weight and good thermal insulation effects. They are widely used in modern buildings. At present, the production of aerated concrete blocks requires the use of foaming agents to generate pores to achieve the purpose of reducing density. Foaming agents include chemical foaming agents and physical foaming agents. Commonly used chemical foaming agents include aluminum powder, hydrogen peroxide, and sulfonates. Aluminum powder and hydrogen peroxide have safety hazards such as explosion due to the generation of hydrogen during use. Sulfonates have more complex pollution characteristics during use. Commonly used physical foaming agents include animal foaming agents and plant foaming agents. During use, irritating pollutant gases will be generated and waste liquid will be discharged. Therefore, the use of foaming agents not only pushes up product costs, but also leads to the discharge of waste and pollutants, and there are production safety hazards. It is an important factor affecting industrial technological progress and product promotion.

[0003] At present, a large amount of construction waste is generated during the construction process of building demolition, industrial and commercial and residential decoration. The composition of construction waste is complex, including ordinary concrete waste, decoration waste, aerated concrete waste, brick, tile, mud and stone waste, etc., which are difficult to handle. In particular, aerated concrete waste (such as abandoned aerated concrete blocks) is more difficult to handle, which has always been a problem in the industry. Generally, when dealing with construction waste, abandoned aerated concrete blocks will be removed, and their resource utilization cannot be realized. At present, there are reports that abandoned aerated concrete blocks are used for landfill or foundation backfill, but their density is small and their water absorption rate is high. In particular, they cannot be compacted to achieve the specified compaction degree, so large-scale engineering applications cannot be carried out; there are also reports that they can be processed into permeable aggregates, putty powder, etc., but due to the small scope of application and limited market demand, the problem of resource disposal of large quantities of abandoned aerated concrete blocks cannot be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a mixing kettle, aerated concrete blocks recycled from construction waste, and a preparation method and application thereof. By using the mixing kettle provided by the present invention to mix materials, no foaming agent is needed, and the recycled aerated concrete blocks can be prepared with construction waste as the main raw material, especially allowing the use of waste aerated concrete blocks in large amounts, thereby realizing their resource disposal.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a stirring kettle, comprising a stirring kettle body, a stirring module, an air pressure sensor 1, an air inlet pipe valve 2, a liquid material pipe valve 3, a powder material pipe valve 5 and a discharge pipe valve 13;

[0007] The stirring module includes a stirring motor 4 and a stirring shaft 14 connected to the stirring motor 4, and a paddle 15 is provided on the stirring shaft 14;

[0008] The shell of the stirring tank body is a sandwich structure, including a stirring tank inner wall 9 and a stirring tank outer shell 11, wherein the stirring tank inner wall 9 is provided with a plurality of vents, a molecular sieve film 10 is provided between the stirring tank inner wall 9 and the stirring tank outer shell 11, and the molecular sieve film 10 is attached to the outer surface of the stirring tank inner wall 9, and the molecular sieve film 10 allows gas to pass through but does not allow water to pass through;

[0009] The shell is provided with four through holes, which are respectively used to install the liquid pipe valve 3, the powder pipe valve 5, the discharge pipe valve 13 and the stirring shaft 14, and the stirring motor 4 is arranged on the outside of the shell; the mixing kettle shell 11 is provided with holes for installing the air pressure sensor 1 and the intake pipe valve 2.

[0010] Preferably, the tensile strength of the molecular sieve film 10 is ≥400N, and the gas flow rate is ≥10m 3 / min.

[0011] Preferably, the diameter of the vent holes on the inner wall 9 of the stirring tank is 1-5 mm, and the ratio of the hole center distance to the hole diameter is 2-4.

[0012] Preferably, the inner side of the inner wall 9 of the stirring tank, the surface of the stirring shaft 14 and the surface of the blade 15 are provided with a wear-resistant coating.

[0013] The present invention provides a method for preparing aerated concrete blocks recycled from construction waste, without using a foaming agent, comprising the following steps:

[0014] The dry powder material is conveyed to the mixing tank through the powder pipe valve 5, wherein the dry powder material comprises recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, reinforcing agent and early strength agent, and the content of recycled fine aggregate from waste aerated concrete blocks in the recycled fine aggregate from construction waste is ≤100%;

[0015] The liquid material is transported to the stirring tank through the liquid material pipe valve 3; the liquid material includes water and a water reducing agent;

[0016] Under the stirring condition of the stirring module, air is inflated into the interlayer of the stirring kettle through the air inlet pipe valve 2, and after the pressure is maintained for mixing, the material is discharged through the discharge pipe valve 13 to obtain a mixed slurry;

[0017] The mixed slurry is sequentially molded and cured to obtain construction waste recycled aerated concrete blocks;

[0018] Wherein, the stirring tank is the stirring tank described in the above technical solution.

[0019] Preferably, calculated by mass, the recycled fine aggregate from construction waste is 200-410 parts, cement is 200-550 parts, mineral powder is 100-400 parts, water reducer is 2-4 parts, modifier is 1-3 parts, thickener is 1-5 parts, reinforcing agent is 0.5-2.5 parts, early strength agent is 1-3 parts, and water is 215-320 parts.

[0020] Preferably, the particle size of the recycled fine aggregate from construction waste is ≤4.75 mm, and the mud content is ≤35%.

[0021] Preferably, the mixing is carried out under a pressure of 0.3 to 0.8 MPa, and the mixing time is 170 to 460 seconds.

[0022] The present invention provides a construction waste recycled aerated concrete block prepared by the preparation method described in the above technical solution, with a dry density of ≤700kg / m 3 , the compressive strength is 3.8~6.2MPa.

[0023] The present invention provides the use of the construction waste recycled aerated concrete blocks described in the above technical solution as building materials.

[0024] The present invention provides a stirring kettle, comprising a stirring kettle body, a stirring module, an air pressure sensor 1, an air inlet pipe valve 2, a liquid material pipe valve 3, a powder material pipe valve 5 and a discharge pipe valve 13; the stirring module comprises a stirring motor 4 and a stirring shaft 14 connected to the stirring motor 4, and a paddle 15 is arranged on the stirring shaft 14; the shell of the stirring kettle body is a sandwich structure, comprising a stirring kettle inner wall 9 and a stirring kettle outer shell 11, and a plurality of vents are arranged on the stirring kettle inner wall 9, and a molecular sieve film 10 is arranged between the stirring kettle inner wall 9 and the stirring kettle outer shell 11, and the molecular sieve film 10 is attached to the outer surface of the stirring kettle inner wall 9, and the molecular sieve film 10 allows gas to pass through but does not allow water to pass through; four through holes are arranged on the shell, which are respectively used to install the liquid material pipe valve 3, the powder material pipe valve 5, the discharge pipe valve 13 and the stirring shaft 14, and the stirring motor 4 is arranged on the outside of the shell; holes for installing the air pressure sensor 1 and the air inlet pipe valve 2 are opened on the stirring kettle outer shell 11.

[0025] By using the mixing tank provided by the present invention, the mixing tank interlayer pressure is increased, and the gas is driven to pass through the molecular sieve film 10 to form small-sized bubbles, which are uniformly mixed into the slurry after stirring, thereby obtaining a mixed slurry with high gas content and uniform bubble distribution. No foaming agent is needed, and the preparation of recycled aerated concrete blocks with construction waste as the main raw material can be realized, and the raw material requirements are low, the process is simple, and the equipment reliability is good. On the one hand, it fundamentally solves the current production safety hazards, environmental pollution, and high production costs caused by the use of foaming agents, and promotes the development of green, environmentally friendly, and low-carbon new building materials technology through technological progress; on the other hand, construction waste is used as the main raw material, especially the use of waste aerated concrete blocks that allow large amounts of admixture, and large-scale resource disposal and utilization of construction waste, especially waste aerated concrete blocks that are currently difficult to dispose of, is realized through the large-scale engineering application of recycled aerated concrete blocks, which has significant economic benefits, environmental benefits, and comprehensive social benefits.

[0026] The results of the examples show that the dry density of the recycled aerated concrete blocks prepared with construction waste as the main raw material based on the stirred tank mixture provided by the present invention is 601-700 kg / m 3 The compressive strength is 3.8~6.2MPa, which has reached the A5.0 B07 standard in the current national standard for similar products "Autoclaved Aerated Concrete Blocks" GB11968-2006, and can effectively meet the actual needs of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the stirring kettle in the present invention, wherein 1-air pressure sensor, 2-inlet pipe valve, 3-liquid material pipe valve, 4-stirring motor, 5-powder material pipe valve, 6-limiter, 7-stirring kettle support frame, 8-stirring shaft fixing bracket, 9-stirring kettle inner wall, 10-molecular sieve film, 11-stirring kettle shell, 12-discharge pipe interface, 13-discharge pipe valve, 14-stirring shaft, 15-paddle, 16-vibration motor. DETAILED DESCRIPTION

[0028] The present invention provides a stirring kettle, comprising a stirring kettle body, a stirring module, an air pressure sensor 1, an air inlet pipe valve 2, a liquid material pipe valve 3, a powder material pipe valve 5 and a discharge pipe valve 13;

[0029] The stirring module includes a stirring motor 4 and a stirring shaft 14 connected to the stirring motor 4, and a paddle 15 is provided on the stirring shaft 14;

[0030] The shell of the stirring tank body is a sandwich structure, including a stirring tank inner wall 9 and a stirring tank outer shell 11, wherein the stirring tank inner wall 9 is provided with a plurality of vents, a molecular sieve film 10 is provided between the stirring tank inner wall 9 and the stirring tank outer shell 11, and the molecular sieve film 10 is attached to the outer surface of the stirring tank inner wall 9, and the molecular sieve film 10 allows gas to pass through but does not allow water to pass through;

[0031] The shell is provided with four through holes, which are respectively used to install the liquid pipe valve 3, the powder pipe valve 5, the discharge pipe valve 13 and the stirring shaft 14, and the stirring motor 4 is arranged on the outside of the shell; the mixing kettle shell 11 is provided with holes for installing the air pressure sensor 1 and the intake pipe valve 2.

[0032] The stirring kettle provided by the present invention includes a stirring module, and the stirring module includes a stirring motor 4 and a stirring shaft 14 connected to the stirring motor 4, and a paddle 15 is provided on the stirring shaft 14. As an embodiment of the present invention, the stirring motor 4 is a variable frequency speed regulating motor that can rotate forward and reverse, and the speed range is preferably 50 to 1500rpm. The present invention has no special restrictions on the material of the stirring shaft 14 and the paddle 15, and has the characteristics of high strength and fatigue resistance, and can meet actual needs. Specifically, it can be a metal material, such as high carbon chromium steel (commonly known as bearing steel). In the present invention, the surface of the stirring shaft 14 and the paddle 15 is preferably provided with a wear-resistant coating, and the material of the wear-resistant coating is preferably metal ceramic or carbon fluorine paint; the present invention has no special restrictions on the thickness of the wear-resistant coating and the specific preparation method, and a solution familiar to those skilled in the art can be adopted. The setting position of the stirring module is described in detail later.

[0033] As an embodiment of the present invention, the stirring module further includes a stirring shaft fixing bracket 8, such as Figure 1 As shown, the stirring shaft fixing bracket 8 is connected to the shell of the stirring tank body and is used to fix the stirring shaft 14.

[0034] The stirring tank provided by the present invention comprises a stirring tank body, the shell of the stirring tank body is a sandwich structure, including a stirring tank inner wall 9 and a stirring tank outer shell 11, and a plurality of vents are arranged on the stirring tank inner wall 9. In the present invention, the thickness of the shell (i.e., the thickness of the sandwich formed by the stirring tank inner wall 9 and the stirring tank outer shell 11) is preferably 1.0 to 1.5 cm; the present invention preferably sets the thickness of the shell in the above range, and in the air compressor (not in Figure 1 As shown in the figure, the air compressor provides high-pressure air for inflating and foaming the slurry inside the stirring tank. When the load capacity meets the requirements, it is beneficial to save materials.

[0035] The present invention has no special limitation on the material of the stirred tank shell 11, and any material that can withstand a pressure of not less than 2 MPa, is impact-resistant, corrosion-resistant, and has a sealed pressure-maintaining function can be used. It is preferably a metal material or a special plastic. Specifically, the metal material can be stainless steel or magnesium-aluminum alloy, and the special plastic can be polytetrafluoroethylene.

[0036] The present invention has no special limitation on the material of the inner wall 9 of the stirring tank, and any material that can withstand a pressure of not less than 2 MPa, is impact-resistant, and is corrosion-resistant can be used, preferably a metal material or a special plastic. Specifically, the metal material can be stainless steel or a magnesium-aluminum alloy, and the special plastic can be polytetrafluoroethylene.

[0037] In the embodiment of the present invention, the materials of the inner wall 9 of the stirring tank and the outer shell 11 of the stirring tank may be the same or different, and the present invention has no special limitation on this.

[0038] In the present invention, a plurality of vents are provided on the inner wall 9 of the stirring kettle, and the aperture of the vents on the inner wall 9 of the stirring kettle is preferably 1 to 5 mm, and the ratio of the hole center distance to the aperture is preferably 2 to 4. In the present invention, a wear-resistant coating is preferably provided on the inner side of the inner wall 9 of the stirring kettle, and the material of the wear-resistant coating is preferably metal ceramic or fluorocarbon paint; the present invention has no special restrictions on the thickness of the wear-resistant coating and the specific preparation method, and the schemes well known to those skilled in the art can be adopted.

[0039] In the present invention, a molecular sieve film 10 is arranged between the inner wall 9 of the stirring tank and the outer shell 11 of the stirring tank, and the molecular sieve film 10 is attached to the outer surface of the inner wall 9 of the stirring tank, and the molecular sieve film 10 allows gas to pass through but does not allow water to pass through. In the present invention, the molecular sieve film 10 is attached to the outer surface of the inner wall 9 of the stirring tank and covers all the vents on the inner wall 9 of the stirring tank. In the present invention, the tensile strength of the molecular sieve film 10 is preferably ≥400N, and the gas flow rate is preferably ≥10m 3 / min; The present invention preferably sets the tensile strength of the molecular sieve film 10 in the above range, which can effectively ensure that it will not be damaged by the impact of high-pressure air during production operations, and meet the requirements of industrial continuous production for equipment stability and reliability; The air flow rate of the molecular sieve film 10 is set in the above range, which can achieve the completion of the predetermined inflation volume within the set process time, which is conducive to reducing the product density and improving product quality. The present invention does not specifically limit the thickness and material of the molecular sieve film 10, and it only needs to meet the above tensile strength and air flow requirements. The molecular sieve film 10 described in the present invention allows gas to pass through but does not allow water to pass through. Specifically, during actual production, a water-containing slurry is placed inside the stirring kettle, and the molecular sieve film 10 does not allow water to pass through, which can ensure that the water-containing slurry will not flow into the interlayer of the stirring kettle, causing cleaning difficulties; At the same time, during actual production, high-pressure gas will be introduced into the interlayer of the stirring kettle, and the molecular sieve film 10 allows gas to pass through, so the high-pressure gas can pass through the molecular sieve film 10 into the slurry to form a foaming effect.

[0040] In the present invention, the stirring kettle comprises an air pressure sensor 1, an air inlet pipe valve 2, a liquid material pipe valve 3, a powder material pipe valve 5 and a discharge pipe valve 13, wherein the air pressure sensor 1 is used to monitor the pressure in the stirring kettle (specifically, to monitor the pressure in the interlayer of the stirring kettle), the air inlet pipe valve 2 is used to ventilate the stirring kettle, the liquid material pipe valve 3 is used to add liquid material into the stirring kettle, the powder material pipe valve 5 is used to add dry powder material into the stirring kettle, and the discharge pipe valve 13 is used to discharge the mixed slurry obtained after mixing in the stirring kettle. As an embodiment of the present invention, the liquid material pipe valve 3, the powder material pipe valve 5 and the discharge pipe valve 13 adopt a pipe clamp valve, which has the characteristics of fast response, wear resistance, and adaptability to mortar-like working media. The setting position of each component is described in detail below.

[0041] In the present invention, four through holes are provided on the shell, which are used to install the liquid pipe valve 3, the powder pipe valve 5, the discharge pipe valve 13 and the stirring shaft 14 respectively, and the stirring motor 4 is arranged on the outside of the shell. In the present invention, the stirring kettle has two working positions when in use, namely, a horizontal state and a vertical state, wherein the vertical state is adopted when adding materials, discharging materials and mixing dry materials, and the horizontal state is adopted when mixing dry materials and wet materials. As an embodiment of the present invention, based on the horizontal state of the stirring kettle, the liquid pipe valve 3 is arranged at the upper end of one side of the shell; the powder pipe valve 5 is arranged at the lower end of one side of the shell; the stirring shaft 14 runs through the center of the stirring kettle, and the stirring motor 4 is located on the outside of the shell, and the paddle 15 is located on the inside of the shell, so as to achieve stirring and mixing of the materials in the stirring kettle; the discharge pipe valve 13 is arranged at the middle position on the other side of the shell. In the present invention, holes for installing the air pressure sensor 1 and the air inlet pipe valve 2 are provided on the mixing kettle shell 11. Specifically, air is ventilated into the interlayer of the shell through the air inlet pipe valve 2, and the air pressure in the mixing kettle interlayer is increased to drive the gas through the molecular sieve film 10 to form small-sized bubbles, which are evenly mixed into the slurry under stirring conditions, thereby obtaining a mixed slurry with high air content and uniform bubble distribution. Without using a foaming agent, it is possible to prepare recycled aerated concrete blocks using construction waste as the main raw material.

[0042] As an embodiment of the present invention, Figure 1 As shown, the mixing kettle further comprises a discharge pipe interface 12, and the discharge pipe interface 12 is connected to the discharge pipe valve 13, and is used for injecting the mixed slurry discharged from the discharge pipe valve 13 into the molding mold for molding.

[0043] As an embodiment of the present invention, Figure 1 As shown, the stirring tank further includes a vibration motor 16, which is disposed on the outside of the shell and on the same side as the discharge pipe valve 13 for assisting discharge.

[0044] As an embodiment of the present invention, the stirred tank further comprises a PLC control system (not shown in Figure 1 The PLC control system is connected with the air pressure sensor 1, the air intake pipe valve 2, the liquid material pipe valve 3, the powder material pipe valve 5 and the discharge pipe valve 13 for regulating the signals thereof.

[0045] As an embodiment of the present invention, Figure 1As shown, the stirring kettle also includes a stopper 6, and its setting position is not particularly limited, and it can be as far away from the center of mass of the stirring kettle as possible to reduce the force; the stirring kettle in the present invention has two working positions when in use: horizontal state and vertical state. Since the overall mass and volume of the stirring kettle are large, the use of the stopper 6 can ensure that the stirring kettle will not shake significantly when in the horizontal state. As an embodiment of the present invention, the stopper 6 is fixed by an electromagnet.

[0046] As an embodiment of the present invention, Figure 1 As shown, the stirring tank further comprises a stirring tank support frame 7, and the stirring tank support frame 7 is located at the center of mass of the stirring tank after the stirring tank bears the working load, and is used to support the stirring tank. The present invention has no special restrictions on the number and arrangement of the stirring tank support frames 7, and a single row or matrix expansion arrangement can be performed according to the production scale. The present invention has no special restrictions on the material of the stirring tank support frame 7, and it has high strength and low deformation characteristics and meets actual needs. Specifically, it can be angle steel, concrete or wood.

[0047] The present invention provides a method for preparing aerated concrete blocks recycled from construction waste, without using a foaming agent, comprising the following steps:

[0048] The dry powder material is conveyed to the mixing tank through the powder pipe valve 5, wherein the dry powder material comprises recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, reinforcing agent and early strength agent, and the content of recycled fine aggregate from waste aerated concrete blocks in the recycled fine aggregate from construction waste is ≤100%;

[0049] The liquid material is transported to the stirring tank through the liquid material pipe valve 3; the liquid material includes water and a water reducing agent;

[0050] Under the stirring condition of the stirring module, air is inflated into the interlayer of the stirring kettle through the air inlet pipe valve 2, and after the pressure is maintained for mixing, the material is discharged through the discharge pipe valve 13 to obtain a mixed slurry;

[0051] The mixed slurry is sequentially molded and cured to obtain construction waste recycled aerated concrete blocks;

[0052] Wherein, the stirring tank is the stirring tank described in the above technical solution.

[0053] First, the raw materials for preparing the construction waste recycled aerated concrete blocks of the present invention are described. According to the physical state of the raw materials, the raw materials for preparing the construction waste recycled aerated concrete blocks include dry powder materials and liquid materials, wherein the dry powder materials include construction waste recycled fine aggregate, cement, mineral powder, modifier, thickener, enhancer and early strength agent, and the liquid materials include water and water reducing agent. In terms of mass fractions, the raw materials for preparing the construction waste recycled aerated concrete blocks include: 200-410 parts of construction waste recycled fine aggregate, 200-550 parts of cement, 100-400 parts of mineral powder, 2-4 parts of water reducing agent, 1-3 parts of modifier, 1-5 parts of thickener, 0.5-2.5 parts of enhancer, 1-3 parts of early strength agent, and 215-320 parts of water.

[0054] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art.

[0055] In terms of mass percentage, the raw materials for preparing the construction waste recycled aerated concrete blocks preferably include 200 to 410 parts of construction waste recycled fine aggregate, more preferably 250 to 350 parts, and further preferably 280 to 300 parts. In the present invention, the particle size of the construction waste recycled fine aggregate is preferably ≤4.75 mm, more preferably ≤2.36 mm; the mud content is preferably ≤35%, more preferably ≤20%, and further preferably 2 to 18%. In the present invention, the construction waste recycled fine aggregate is specifically recycled fine aggregate produced from construction waste. The present invention has no special limitation on the source of the construction waste, and construction waste with sources well known to those skilled in the art can be used. In the present invention, the construction waste recycled fine aggregate preferably includes at least one of waste aerated concrete block recycled fine aggregate, waste red brick recycled fine aggregate, waste ceramic recycled fine aggregate and mixed recycled fine aggregate, wherein the content of waste aerated concrete block recycled fine aggregate in the construction waste recycled fine aggregate is ≤100%, specifically 0-100%, and further 50-100%; specifically, the construction waste recycled fine aggregate can be all waste aerated concrete block recycled fine aggregate, or all non-waste aerated concrete block recycled fine aggregate, or partly waste aerated concrete block recycled fine aggregate, and at the same time, at least one of waste red brick recycled fine aggregate, waste ceramic recycled fine aggregate and mixed recycled fine aggregate is added. The present invention has no special limitation on the specific proportion of each component. In the present invention, the components of the mixed recycled fine aggregate preferably include concrete, sintered bricks, ceramics and glass, and the mass ratio of the concrete, sintered bricks, ceramics and glass is preferably (40-50): (15-25): (20-30): (8-12), and more preferably 45:20:25:10.

[0056] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 200 to 550 parts of cement, more preferably 250 to 350 parts, and more preferably 280 to 300 parts. In the present invention, the cement is preferably 42.5R ordinary Portland cement.

[0057] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 100 to 400 parts of mineral powder, more preferably 240 to 350 parts, and further preferably 280 to 300 parts. In the present invention, the mineral powder is preferably S95 grade mineral powder or S105 grade mineral powder.

[0058] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 2 to 4 parts of a water reducer, more preferably 2.5 to 3.5 parts, and further preferably 2.8 to 3 parts. In the present invention, the water reducer is preferably a polycarboxylic acid water reducer mother liquor containing only a water reducing component; in the embodiment of the present invention, the polycarboxylic acid water reducer mother liquor produced by Shenzhen Maidi Concrete Admixture Co., Ltd. is specifically used.

[0059] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 1 to 3 parts of a modifier, more preferably 1.5 to 2.5 parts, and further preferably 1.8 to 2 parts. In the present invention, the modifier is preferably industrial grade zinc stearate or industrial grade calcium stearate.

[0060] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 1 to 5 parts of thickener, more preferably 2.2 to 4 parts, and further preferably 2.6 to 3 parts. In the present invention, the thickener is preferably hydroxypropyl methylcellulose and / or redispersible latex powder, and the viscosity of the hydroxypropyl methylcellulose is preferably 4000.

[0061] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 0.5 to 2.5 parts of reinforcing agent, more preferably 1 to 2 parts, and further preferably 1.3 to 1.5 parts. In the present invention, the reinforcing agent is preferably industrial grade calcium acrylate.

[0062] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 1 to 3 parts of an early strength agent, more preferably 1.4 to 2.5 parts, and further preferably 1.5 to 2 parts. In the present invention, the early strength agent preferably includes industrial grade anhydrous calcium chloride or industrial grade lithium carbonate.

[0063] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably include 215 to 320 parts of water, more preferably 224 to 290 parts, and further preferably 240 to 250 parts.

[0064] Based on the mass fraction of the recycled fine aggregate from construction waste, the raw materials for preparing the recycled aerated concrete blocks from construction waste preferably also include 40 to 55 parts of silica fume, more preferably 45 to 50 parts. The preferred addition of silica fume in the present invention is beneficial to improving the strength of the recycled aerated concrete blocks from construction waste.

[0065] The present invention is based on the mixing kettle described in the above technical solution, and adopts the above-mentioned raw materials to prepare the construction waste recycled aerated concrete blocks. Specifically, the present invention preferably stores the other raw materials except water in separate warehouses after passing the on-site inspection, and turns on the production equipment for power-on inspection to ensure that each component works normally, and then determines the single raw material dosage according to the raw material ratio required for production, and feeds the materials into the mixing kettle through a gravity feeder or a screw feeder after metering, obtains a mixed slurry through mixing, and then successively undergoes molding and curing to obtain construction waste recycled aerated concrete blocks. The preparation method of the construction waste recycled aerated concrete blocks is described in detail below.

[0066] The present invention conveys dry powder materials to the stirring tank through the powder pipe valve 5, and the dry powder materials include recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, enhancer and early strength agent. The present invention preferably mixes recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, enhancer and early strength agent to obtain dry powder materials, and then conveys the obtained dry powder materials to the stirring tank through the powder pipe valve 5. Before conveying the dry powder materials to the stirring tank, the present invention preferably adjusts the stirring tank to a vertical state, so that the powder pipe valve 5 faces upward to receive the material, and turns on the stirring motor 4. After the dry powder materials are conveyed, the powder pipe valve 5 is closed, and the stirring tank is kept in a vertical state and continues to stir for 150 to 200 seconds to mix the dry powder materials in the stirring tank evenly.

[0067] After the dry powder material is transported to the stirring tank, the present invention transports the liquid material to the stirring tank through the liquid material pipe valve 3; the liquid material includes water and a water reducer. The present invention preferably mixes water and a water reducer to obtain a liquid material, and then transports the liquid material to the stirring tank through the liquid material pipe valve 3, closes the liquid material pipe valve 3, adjusts the stirring tank to a horizontal state, and continues stirring for 180 to 480 seconds to evenly mix the liquid material and the dry powder material in the stirring tank.

[0068] After the liquid material is transported to the stirring kettle, the present invention inflates the interlayer of the stirring kettle through the air inlet valve 2 under the stirring condition of the stirring module, and after mixing by maintaining pressure, discharges the material through the discharge pipe valve 13 to obtain a mixed slurry. In the present invention, the mixing is preferably carried out under the condition of a pressure of 0.3 to 0.8 MPa, more preferably 0.5 to 0.6 MPa; the mixing time is preferably 170 to 460 s, more preferably 250 to 300 s; the mixing time is measured from the start of inflation. The present invention preferably inflates the interlayer of the stirring kettle with air to maintain the pressure in the interlayer at 0.3 to 0.8 MPa. Specifically, the gas pressure in the interlayer can be controlled by a PLC control system. When it is lower than the set value, the PLC control system controls the air inlet valve 2 to open and replenish gas. When the preset parameter is reached, the PLC control system controls the air inlet valve 2 to close to keep the gas pressure in the interlayer at the set value. After the mixing is completed, the present invention preferably closes the air inlet valve 2, adjusts the stirring kettle to a vertical state, makes the discharge pipe valve 13 face downward, opens the discharge pipe valve 13, and simultaneously reverses the stirring motor 4 to discharge. During the discharge process, the present invention preferably turns on the vibration motor 16 to assist in the discharge.

[0069] After obtaining the mixed slurry, the present invention sequentially molds and cures the mixed slurry to obtain aerated concrete blocks recycled from construction waste. The present invention preferably injects the mixed slurry into the molding mold through the discharge pipe interface 12, and after natural curing at room temperature and pressure for 6 to 10 hours under vibration-free conditions, demolds to obtain molded blocks. In the present invention, the molding mold after demolding is cleaned and repaired and continues to be used for molding. The present invention preferably transports the molded blocks to the curing area, and continues to naturally cure at room temperature and pressure for 4 to 7 days to obtain aerated concrete blocks recycled from construction waste. The present invention does not specifically limit the specific curing time in the curing area, and the curing time familiar to those skilled in the art can be used. Specifically, when the average temperature in summer is 30°C, the curing age is set to 4 days, and when the average temperature in winter is 10°C, the curing age is set to 7 days.

[0070] The present invention provides a construction waste recycled aerated concrete block prepared by the preparation method described in the above technical solution, wherein the dry density of the construction waste recycled aerated concrete block is ≤700kg / m 3 The compressive strength is 3.8~6.2MPa, which meets the A5.0 B07 standard in the current national standard for similar products "Autoclaved Aerated Concrete Blocks" GB11968-2006, and can effectively meet the actual needs of engineering applications.

[0071] The present invention provides the use of the construction waste recycled aerated concrete blocks described in the above technical solution as building materials.

[0072] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] In the following examples and comparative examples, the water reducing agent used was purchased from Shenzhen Maidi Concrete Admixture Co., Ltd., and the viscosity of the hydroxypropyl methylcellulose used was 4000.

[0074] Example 1

[0075] In terms of mass fraction, the raw materials for preparing the construction waste recycled aerated concrete blocks in this embodiment are: 350 kg of construction waste recycled fine aggregate, 350 kg of cement, 300 kg of mineral powder, 3 kg of water reducer, 2 kg of modifier, 2.6 kg of thickener, 1.5 kg of enhancer, 2 kg of early strength agent, and 224 kg of water;

[0076] Among them, all the recycled fine aggregates from construction waste are recycled fine aggregates from discarded aerated concrete blocks, the particle size of the recycled fine aggregates from construction waste is ≤4.75mm, and the mud content is 12%; the cement is ordinary Portland cement with grade 42.5R; the mineral powder is S95 grade mineral powder; the water reducer is a polycarboxylic acid water reducer mother liquor containing only water reducing components; the modifier is industrial grade calcium stearate; the thickener is hydroxypropyl methylcellulose; the enhancer is industrial grade calcium acrylate; and the early strength agent is industrial grade anhydrous calcium chloride.

[0077] based on Figure 1 The mixing kettle shown in the figure is used to prepare aerated concrete blocks recycled from construction waste, comprising the following steps:

[0078] Adjust the stirring kettle to a vertical state, add the recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, reinforcing agent and early strength agent into the stirring kettle through the material pipe valve 5, start the stirring motor 4 for stirring, and after the dry powder material is transported, close the powder pipe valve 5, keep the stirring kettle in a vertical state and continue stirring;

[0079] Mix water and a water reducing agent to obtain a liquid material, then transport the liquid material to the stirring tank through the liquid material pipe valve 3, close the liquid material pipe valve 3, adjust the stirring tank to a horizontal state and continue stirring;

[0080] Under stirring conditions, air is charged into the interlayer of the stirring kettle through the air inlet pipe valve 2 until the pressure in the interlayer of the stirring kettle reaches 0.6 MPa, and the pressure is maintained and stirring is continued until the total stirring time is 300 seconds (calculated from the start of inflation); after the mixing is completed, the air inlet pipe valve 2 is closed, the stirring kettle is adjusted to a vertical state, the discharge pipe valve 13 is downward, the discharge pipe valve 13 is opened, the stirring motor 4 is controlled to reverse for discharging, and the vibration motor 16 is turned on during the discharging process to assist in discharging, so as to obtain a mixed slurry;

[0081] The mixed slurry is grouted into the forming mold through the discharge pipe interface 12, and after natural curing for 12 hours at room temperature and pressure under vibration-free conditions, the mold is removed to obtain the formed blocks; the forming mold after demolding is cleaned and repaired and then continued to be used for forming; the formed blocks are transported to the curing area, and continue to be naturally cured at room temperature (average temperature is 10°C) and normal pressure for 7 days to obtain construction waste recycled aerated concrete blocks.

[0082] The test results were carried out according to the method specified in "Autoclaved Aerated Concrete Blocks" (GB 11968-2006). The results showed that the dry density of the construction waste recycled aerated concrete blocks prepared in this embodiment was 601 kg / m 3 , the compressive strength is 5.6MPa.

[0083] Example 2

[0084] In terms of mass fraction, the raw materials for preparing the construction waste recycled aerated concrete blocks in this embodiment are: 410 kg of construction waste recycled fine aggregate, 300 kg of cement, 240 kg of mineral powder, 3 kg of water reducer, 1 kg of modifier, 2.2 kg of thickener, 1.5 kg of enhancer, 2 kg of early strength agent, and 290 kg of water;

[0085] Among them, the recycled fine aggregate from construction waste is specifically a mixed recycled fine aggregate, whose ingredients include concrete, sintered bricks, ceramics and glass, and the mass ratio of the concrete, sintered bricks, ceramics and glass is 45:20:25:10. The particle size of the recycled fine aggregate from construction waste is ≤4.75mm, and the mud content is 27%; the cement is ordinary Portland cement with grade 42.5R; the mineral powder is S95 grade mineral powder; the water reducer is a polycarboxylic acid water reducer mother liquor containing only water reducing components; the modifier is industrial grade calcium stearate; the thickener is hydroxypropyl methylcellulose; the enhancer is industrial grade calcium acrylate; and the early strength agent is industrial grade anhydrous calcium chloride.

[0086] The above-mentioned raw materials were used to prepare construction waste recycled aerated concrete blocks according to the operating conditions of Example 1.

[0087] The construction waste recycled aerated concrete blocks were tested according to the method of Example 1. The results showed that the dry density was 696 kg / m 3, the compressive strength is 4.9MPa.

[0088] Example 3

[0089] In terms of mass fraction, the raw materials for preparing the aerated concrete blocks from recycled construction waste in this embodiment are: 300 kg of recycled fine aggregate from construction waste, 300 kg of cement, 300 kg of mineral powder, 2.5 kg of modifier, 3 kg of thickener, 2.5 kg of enhancer, 1.4 kg of early strength agent, 3 kg of water reducer, and 290 kg of water;

[0090] Among them, all the recycled fine aggregates from construction waste are recycled fine aggregates from discarded red bricks, the particle size of the recycled fine aggregates from construction waste is ≤4.75mm, and the mud content is 2%; the cement is ordinary Portland cement with grade 42.5R; the mineral powder is S105 grade mineral powder; the water reducer is a polycarboxylic acid water reducer mother liquor containing only water reducing components; the modifier is industrial grade calcium stearate; the thickener is hydroxypropyl methylcellulose; the enhancer is industrial grade calcium acrylate; and the early strength agent is industrial grade anhydrous calcium chloride.

[0091] The above-mentioned raw materials were used to prepare construction waste recycled aerated concrete blocks according to the operating conditions of Example 1.

[0092] The construction waste recycled aerated concrete blocks were tested according to the method of Example 1. The results showed that the dry density was 689 kg / m 3 , the compressive strength is 4.5MPa.

[0093] Example 4

[0094] In terms of mass fraction, the raw materials for preparing the construction waste recycled aerated concrete blocks in this embodiment are: 300 kg of construction waste recycled fine aggregate, 350 kg of cement, 300 kg of mineral powder, 2 kg of modifier, 2.5 kg of thickener, 2 kg of enhancer, 1.5 kg of early strength agent, 2.8 kg of water reducer, and 250 kg of water;

[0095] Among them, 300kg of recycled fine aggregate from construction waste is specifically 150kg of recycled fine aggregate from waste aerated concrete blocks and 150kg of mixed recycled fine aggregate. The composition of the mixed recycled fine aggregate is consistent with the composition of the mixed recycled fine aggregate in Example 2. The particle size of the recycled fine aggregate from construction waste is ≤4.75mm, and the mud content is 18%; the cement is ordinary Portland cement with grade 42.5R; the mineral powder is S95 grade mineral powder; the water reducer is a polycarboxylate water reducer mother liquor containing only water reducing components; the modifier is industrial grade zinc stearate; the thickener is redispersible latex powder; the reinforcing agent is industrial grade calcium acrylate; and the early strength agent is industrial grade anhydrous calcium chloride.

[0096] The above-mentioned raw materials were used to prepare construction waste recycled aerated concrete blocks according to the operating conditions of Example 1.

[0097] The construction waste recycled aerated concrete blocks were tested according to the method of Example 1. The results showed that the dry density was 693 kg / m 3 , the compressive strength is 3.8MPa.

[0098] Example 5

[0099] In terms of mass fraction, the raw materials for preparing the aerated concrete blocks from recycled construction waste in this embodiment are: 300 kg recycled fine aggregate from construction waste, 550 kg cement, 100 kg mineral powder, 50 kg silica fume, 2 kg modifier, 2 kg thickener, 2 kg enhancer, 3 kg early strength agent, 3 kg water reducer, and 217 kg water;

[0100] Among them, the recycled fine aggregate from construction waste is specifically recycled fine aggregate from waste ceramics, the particle size of the recycled fine aggregate from construction waste is ≤4.75mm, and the mud content is 4%; the cement is ordinary Portland cement with grade 42.5R; the mineral powder is S95 grade mineral powder; the water reducer is a polycarboxylic acid water reducer mother liquor containing only water reducing components; the modifier is industrial grade calcium stearate; the thickener is redispersible latex powder; the enhancer is industrial grade calcium acrylate; and the early strength agent is industrial grade anhydrous calcium chloride.

[0101] The above-mentioned raw materials were used to prepare construction waste recycled aerated concrete blocks according to the operating conditions of Example 1.

[0102] The construction waste recycled aerated concrete blocks were tested according to the method of Example 1. The results showed that the dry density was 700 kg / m 3 , the compressive strength is 6.2MPa.

[0103] Comparative Example 1

[0104] Aerated concrete blocks were prepared according to the method of Example 1, except that the recycled fine aggregate from construction waste was replaced with natural fine aggregate, the particle size of the natural fine aggregate was ≤4.75 mm, and the mud content was 15%.

[0105] The aerated concrete block was tested according to the method of Example 1. The results showed that the dry density was 948 kg / m 3 , the compressive strength is 5.5MPa.

[0106] It can be seen from the above embodiments and comparative examples that by using the recycled fine aggregate from construction waste as the main raw material and adopting the device and method provided by the present invention, recycled aerated concrete block products of grade A05 B07 that meet the requirements of the standard of "Autoclaved Aerated Concrete Block" (GB11968-2006) can be produced, especially when a large amount of recycled fine aggregate from waste aerated concrete blocks is used, the product density grade can be further reduced to obtain a lightweight effect. If natural fine aggregate is used to prepare aerated concrete blocks, the density of the prepared aerated concrete blocks will increase due to the low water absorption rate and poor air retention capacity of natural fine aggregate.

[0107] The present invention uses construction waste as the main raw material, and uses recycled fine aggregate to replace natural sand to prepare aerated concrete blocks with high strength, low density, and heat preservation and sound insulation effects. The large-scale consumption of construction waste is achieved through the engineering application of recycled building materials products. It can not only consume a large amount of construction waste, effectively alleviate the urban development pressures such as land acquisition and landfill, transportation, exhaust emissions, and dust control brought about by the "garbage siege", but also save a large amount of natural sand and stone mining, and has significant economic benefits, environmental benefits, and comprehensive social benefits. In particular, in the present invention, waste aerated concrete blocks can be used in large amounts as the main raw materials, which not only provides a solution to the current industry development problems of large emissions and difficult disposal of waste aerated concrete blocks, but also can utilize the fine aggregate of waste aerated concrete blocks to promote the working characteristics of "false setting", and further limit the escape of bubbles in the product by effectively reducing the fluidity of the mixed slurry, thereby obtaining the beneficial effects of lower density and lower cost than existing products.

[0108] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A stirred tank, characterized in that: It comprises a stirring kettle body, a stirring module, an air pressure sensor (1), an air inlet pipe valve (2), a liquid material pipe valve (3), a powder material pipe valve (5) and a discharge pipe valve (13); The stirring module comprises a stirring motor (4) and a stirring shaft (14) connected to the stirring motor (4), and a paddle (15) is provided on the stirring shaft (14); The shell of the stirring tank body is a sandwich structure, comprising an inner wall (9) of the stirring tank and an outer shell (11) of the stirring tank, wherein a plurality of vents are arranged on the inner wall (9) of the stirring tank, and a molecular sieve film (10) is arranged between the inner wall (9) of the stirring tank and the outer shell (11), and the molecular sieve film (10) is attached to the outer surface of the inner wall (9) of the stirring tank, and the molecular sieve film (10) allows gas to pass through but does not allow water to pass through; The shell is provided with four through holes, which are respectively used to install the liquid material pipe valve (3), the powder material pipe valve (5), the discharge pipe valve (13) and the stirring shaft (14), and the stirring motor (4) is arranged on the outside of the shell; the stirring kettle shell (11) is provided with holes for installing the air pressure sensor (1) and the air inlet pipe valve (2); It also includes a discharge pipe interface (12), wherein the discharge pipe interface (12) is connected to the discharge pipe valve (13); It also includes a vibration motor (16), which is arranged on the outside of the shell and on the same side as the discharge pipe valve (13).

2. The stirred tank according to claim 1, characterized in that The tensile strength of the molecular sieve film (10) is ≥400N, and the gas flow rate is ≥10m 3 / min.

3. The stirred tank according to claim 1, characterized in that The diameter of the vent holes on the inner wall (9) of the stirring kettle is 1 to 5 mm, and the ratio of the hole center distance to the hole diameter is 2 to 4.

4. The stirred tank according to claim 1, characterized in that The inner side of the inner wall (9) of the stirring tank, the surface of the stirring shaft (14) and the surface of the blade (15) are provided with a wear-resistant coating.

5. A method for preparing aerated concrete blocks recycled from construction waste, characterized in that: Without using a foaming agent, the method comprises the following steps: The dry powder material is conveyed to the stirring kettle through the powder pipe valve (5), wherein the dry powder material comprises recycled fine aggregate from construction waste, cement, mineral powder, modifier, thickener, reinforcing agent and early strength agent, and the content of recycled fine aggregate from waste aerated concrete blocks in the recycled fine aggregate from construction waste is ≤100%; The liquid material is transported to the stirring tank through a liquid material pipe valve (3); the liquid material includes water and a water reducing agent; Under the stirring condition of the stirring module, air is inflated into the interlayer of the stirring kettle through the air inlet pipe valve (2), and after mixing the materials under pressure, the materials are discharged through the discharge pipe valve (13) to obtain a mixed slurry; The mixed slurry is sequentially molded and cured to obtain construction waste recycled aerated concrete blocks; Wherein, the stirred tank is the stirred tank according to any one of claims 1 to 4.

6. The preparation method according to claim 5, characterized in that: Calculated by mass, the recycled fine aggregate from construction waste is 200-410 parts, cement is 200-550 parts, mineral powder is 100-400 parts, water reducer is 2-4 parts, modifier is 1-3 parts, thickener is 1-5 parts, reinforcing agent is 0.5-2.5 parts, early strength agent is 1-3 parts, and water is 215-320 parts.

7. The preparation method according to claim 5 or 6, characterized in that: The particle size of the recycled fine aggregate from construction waste is ≤4.75 mm, and the mud content is ≤35%.

8. The preparation method according to claim 5, characterized in that: The mixing is carried out under a pressure of 0.3-0.8 MPa, and the mixing time is 170-460 seconds.

9. The construction waste recycled aerated concrete block prepared by the preparation method according to any one of claims 5 to 8, characterized in that: Dry density ≤700kg / m 3 , the compressive strength is 3.8~6.2MPa.

10. Use of the construction waste recycled aerated concrete blocks as claimed in claim 9 as building materials.

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