Preparation method of ceramsite concrete

Abstract

The invention discloses a preparation method of ceramsite concrete, which comprises the following steps: raw material preparation, raw material transportation treatment, ingredient stirring, granulation drying, high-temperature roasting, ceramsite concrete manufacturing, waste heat recycling, flue gas treatment, environment-friendly process flow and production line automatic control description. The method has the advantages that graphite slag, gold slag, iron-ore slag and other general industrial solid wastes are adopted as raw materials, and the green building material product, namely the ceramsite lightweight aggregate, is prepared through the working procedures of raw material treatment, ingredient stirring, granulation and drying, high-temperature roasting, finished product cooling, waste heat recycling and tail gas treatment; according to the method, the treatment targets of reduction, harmlessness and recycling of various solid wastes are achieved, the homogenization degree of finished products is high, the environmental protection advantage is obvious, the intelligent control degree of a production line is high, the optimal proportion of ceramsite concrete is obtained through multiple times of test mixing, it is ensured that the concrete reaches the design strength and performance, and product optimization is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of ceramsite concrete, in particular to a preparation method of ceramsite concrete. Background Art

[0002] Ceramic granules: As the name implies, ceramsite particles. Most of the appearance of ceramsite is round or oval spheres, but some imitation gravel ceramsite is not round or oval spheres, but irregular gravel. Ceramic granule concrete is a concrete formed by mixing ceramsite with traditional stones, cement and sand. Compared with traditional concrete, it is lighter and more environmentally friendly. It is a new type of environmentally friendly high-quality building material. Due to the microporous structure inside the lightweight aggregate, the lightweight aggregate has the excellent properties of small bulk density, high strength, good thermal insulation and sound insulation, fire resistance, chemical corrosion resistance, bacterial corrosion resistance, good seismic resistance and strong construction adaptability, and has a wide range of applications. As a lightweight aggregate for building materials, it is used in building concrete and road construction; in agriculture, it is used to improve heavy soil and soilless cultivation base materials; in paint, rubber, and nylon, it is used as a filler. In recent years, lightweight aggregate has gradually been used in water treatment as a microbial carrier, opening up a broad space for it in the field of environmental protection.

[0003] Expanded clay concrete has many advantages, but to better bring out these advantages requires the coordination of various materials and processes. Therefore, when using expanded clay concrete, you must pay attention to using materials that meet quality requirements, and in the process of constructing the surface layer, the cushion layer must also be covered with protective materials. Expanded clay concrete has a small surface density and large voids, so it has strong water absorption. For this reason, during construction, attention must be paid to mixing on site, and when stirring, attention must be paid to strictly controlling the amount of water used. Summary of the invention

[0004] The present invention provides a method for preparing ceramsite concrete. This project adopts graphite slag, gold slag, iron slag and other general industrial solid wastes as raw materials, and prepares a green building material product - ceramsite lightweight aggregate through raw material processing, batching and mixing, granulation and drying, high-temperature roasting, finished product cooling, waste heat recovery and tail gas treatment processes, so as to achieve the treatment and disposal goals of "reduction, harmlessness and resource utilization" of various solid wastes to solve the above problems.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for preparing ceramsite concrete, comprising the following steps: S1: Raw material preparation: prepare graphite slag, gold slag, iron slag and other powdered raw materials as raw materials for ceramsite, and also prepare cement, sand, clean water and admixtures; S2: Transportation and processing of ceramsite raw materials: Pump them to the raw material warehouse for storage, and ensure sealed transportation throughout the process without dust leakage. If there is municipal sludge plastic raw material, it needs to be transported to the sludge buffer warehouse for standby via special conveying equipment, and ensure sealed micro-negative pressure transportation throughout the process without odor leakage; S3: Mixing of ceramsite ingredients: graphite slag, gold slag, iron slag and other powdered raw materials are sent to the top of the mixer by a closed screw conveyor for metering control; municipal sludge and other plastic raw materials are pumped to the top of the mixer for standby use; S4: Ceramic granulation and drying: The high-speed mixed materials are sent to the granulator for granulation. The raw material balls after granulation are sent to a special dryer for drying. The dried balls are sent to a waterfall rotary kiln for roasting. S5: High-temperature roasting of ceramsite: After the dry material balls enter the kiln, the waterfall rotary kiln rotates at a preset speed. The temperature in the kiln is adjusted by the burner. The relevant operation accuracy is ±5°C. The remote operator in the central control room monitors and adjusts the air supply and fuel supply in real time according to the flame monitoring system and the burner control system. After the material balls are fully roasted and melted in the waterfall kiln, they fall into the vibrating fluidized bed cooler for cooling. The cooled ceramsite is sent to the finished product screen, and different specifications are screened according to market demand and packaged and sent to the finished product warehouse for storage; S6: Mix the prepared ceramsite with cement, sand, clean water and admixtures. Pour the sand and cement into a mixer and dry mix them evenly. Then add the pre-wetted ceramsite and continue dry mixing for 1 to 2 minutes. According to the designed water-cement ratio, add water and continue stirring for 3 to 5 minutes. The mixture is uniform. Transport the mixed ceramsite concrete to the construction site and pour it into the mold. The pouring process should be carried out in layers. The thickness of each layer should be controlled between 30 and 40 cm. Use a vibrating rod to vibrate to remove bubbles in the concrete and increase the density. Finally, ceramsite concrete is obtained.

[0006] Preferably, the material in S3 is sent to a vertical turbulent mixer for mixing according to system control requirements, and each component in the material is mixed with water through high-speed stirring.

[0007] Preferably, after the S5 is calcined at high temperature, waste heat is recycled and flue gas is treated. The drying heat source comes from two directions. One is the heat collected by cooling the expanded clay in the cooler; the other is the waste heat of the tail gas generated during the calcination process of the rotary kiln. The tail gas discharged from the dryer is collected centrally and then discharged after comprehensive treatment of dust removal and desulfurization.

[0008] Preferably, the waste heat recycling device extracts the heat from the kiln exhaust gas and uses it for drying the raw balls, so that the drying stage does not require an external heat source; the waste heat from the cooler is also recovered, and after heat balance calculation, in addition to ball drying, it can also be used for workshop heating and bathing purposes.

[0009] Preferably, the flue gas discharged from the rotary kiln in S5 is subjected to SNCR denitrification treatment and then to dust removal, and is sent to a heat exchange device; the tail gas after heat exchange is transported to a special dryer through the clean air after the SCR denitrification device; the flue gas cooled by the vibration cooler is sent to a special dryer for raw material ball drying after dust removal together with the clean air after heat exchange.

[0010] Preferably, it is characterized in that: the environmental protection process includes the treatment of waste water, waste residue, waste gas and noise.

[0011] Preferably, the source of the process wastewater is flushing wastewater, laboratory wastewater and a small amount of domestic sewage; excess wastewater can be recycled to the production line for use as production water.

[0012] Preferably, the production method adopts gypsum desulfurization, and the waste residue produced is a small amount of desulfurized gypsum, which can be used as raw material for the production line after dehydration.

[0013] Preferably, the exhausted waste gas meets emission standards after dust removal, wet desulfurization and wet electrostatic precipitator.

[0014] Preferably, the noise comes from induced draft fans, desulfurization towers, and air compressors. The noise prevention and control measures are to select efficient, stable, and low-noise equipment from the source, and to install silencers and noise reduction devices on equipment with higher noise levels. Shock-absorbing bases are used for fans, and flexible joints are used at connections; compensating joints are set on air ducts to reduce noise generated by vibration, and basic shock absorption is used for cooling tower noise.

[0015] Preferably, the suitable ceramsite content in S6 is 40% to 60%, and the ratio of cement to sand is adjusted according to the engineering strength requirements. The best mix ratio is determined through multiple tests. The selection of raw materials in S1 includes ceramsite (select ceramsite that meets the specifications, generally select ceramsite with a particle size between 4 and 20 mm, and pre-wet the ceramsite in advance), cement (select ordinary Portland cement and other types of cement suitable for concrete), sand (select medium-coarse sand, and the mud content should be controlled below 5%), clean water (must be clean and cannot contain substances harmful to concrete) and admixtures (such as water reducers and expansion agents, added as needed).

[0016] In summary, due to the adoption of the above technology, the beneficial effects of the present invention are: 1. Compared with the existing technology, the advantages are: large solid waste consumption, obvious synergistic treatment effect, and can synergistically treat different types of industrial solid waste and hazardous waste. It is widely used in the treatment and disposal of red mud, (inferior) fly ash, coal gangue, (gold, iron, molybdenum) tailings, river silt, municipal sludge, gasification slag, engineering slag, general solid waste, fly ash, cyanide-containing waste slag, chromium mud, and HW17 sludge.

[0017] 2. Compared with the existing technology, the creativity lies in: the equipment is highly efficient and energy-saving, and the unit product production cost is reduced by more than 1 / 2. The core roasting equipment: waterfall rotary kiln, adopts a unique structural design. The fly ash and sludge light aggregate production line constructed by the company has been identified by the National Building Materials Industry Cement Energy Efficiency and Environmental Protection Evaluation Inspection and Testing Center as having a heat consumption of about 41 kg of standard coal per ton of light aggregate. Compared with the heat consumption of 90 kg of standard coal per unit of light aggregate in the traditional plug-in rotary kiln, the energy saving effect is as high as more than 50%, which has great energy-saving and consumption-reducing demonstration significance. The production line is equipped with a waste heat recycling device, which extracts the heat from the kiln exhaust gas and uses it for drying the raw material balls, so that the drying section does not require an external heat source; the waste heat of the cooler is also recovered. After heat balance calculation, in addition to drying the balls, it can also be used for workshop heating and bathing purposes, realizing the full and efficient utilization of the production line's heat energy to the greatest extent.

[0018] 3. This project uses graphite slag, gold slag, iron slag and other general industrial solid waste as raw materials. After raw material processing, ingredient mixing, granulation drying, high-temperature roasting, finished product cooling, waste heat recovery and tail gas treatment processes, a green building material product - expanded clay lightweight aggregate is prepared to achieve the treatment and disposal goals of "reduction, harmlessness and resource utilization" of various solid wastes. The finished product has a high degree of homogeneity, obvious environmental advantages and a high degree of intelligent control of the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, so that other features, purposes and advantages of the present invention become more obvious. The accompanying drawings of the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 It is a preparation flow chart of ceramsite concrete of the present invention; Figure 2 It is a plan layout diagram of the project of the present invention; Figure 3 It is a process flow chart of the production line of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", and "fix" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances of the specification.

[0023] The present invention provides Figure 1 A method for preparing ceramsite concrete is shown, and the steps are as follows: 1. Processing of ceramsite raw materials Graphite slag, gold slag, iron slag and other powdered raw materials are transported to the factory area via special conveying equipment and pumped to the raw material warehouse for storage. The whole process is guaranteed to be sealed and there is no dust leakage. If there is municipal sludge plastic raw material, it needs to be transported to the sludge buffer warehouse for standby via special conveying equipment. The whole process is guaranteed to be sealed and slightly negative pressure conveyed without odor leakage.

[0024] 2. Mixing of ceramsite ingredients Graphite slag, gold slag, iron slag and other powdered raw materials are sent to the top of the mixer by a closed screw conveyor for metering control; (or) municipal sludge and other plastic raw materials are pumped to the top of the mixer for standby use. The above materials are sent to the vertical turbulent mixer for mixing according to the system control requirements. After high-speed mixing, the various components in the materials are fully mixed with water to ensure the homogeneity of the mixture; The above materials are sent to the vertical turbulent mixer for mixing according to the system control requirements. After high-speed stirring, the various components in the materials are fully mixed with water to ensure the homogeneity of the mixture. The stirred mixture is sent to the aging warehouse for aging through a belt. The aging of the mixture ensures that the water in the mixture has enough time to enter the interior from the surface and distribute evenly; at the same time, the mixture is dispersed and plasticized; the organic matter forms organic colloid substances, which further increases the plasticity of the raw materials, can improve the molding performance of the mixture and the performance of the finished product, ensure the stability of the material, and is conducive to the subsequent process of ball drying.

[0025] 3. Ceramsite granulation and drying The aged material is sent to the metering and speed regulating device and then to the granulator for granulation (differentiated granulation equipment is determined according to product market requirements); the raw material balls after granulation are sent to the shaping machine for shaping; the shaped raw material balls are sent to the special dryer for drying, and the dried raw material balls are sent to the waterfall rotary kiln for roasting.

[0026] 4. High temperature calcination of ceramsite After the dry material balls enter the kiln, the waterfall rotary kiln rotates at a predetermined speed, and the temperature in the kiln is adjusted by the burner, with a relevant operation accuracy of ±5°C. The remote operator in the central control room monitors and adjusts the air supply and fuel supply in real time according to the flame monitoring system and the burner control system. After the material balls are fully roasted and melted in the waterfall kiln, they fall into the cooler for cooling. The cooled ceramsite is sent to the finished product screen, and different specifications are screened according to market demand and packaged and sent to the finished product storage area for storage.

[0027] 5. Manufacturing of ceramsite concrete (1) After the ceramsite is manufactured, prepare the raw materials required for ceramsite concrete, including ceramsite (select ceramsite that meets the specifications, generally select ceramsite with a particle size between 4 and 20 mm, and pre-wet the ceramsite in advance), cement (usually select ordinary Portland cement or other types of cement suitable for concrete), sand (select medium-coarse sand, and the mud content should be controlled below 5%), clean water (must be clean and must not contain substances harmful to concrete) and admixtures (such as water reducer, expansion agent, etc., added as needed); (2) Reasonable mix design is the key to ensuring the performance of ceramsite concrete. Generally speaking, the appropriate ceramsite content is 40% to 60%, and the ratio of cement and sand is adjusted according to the strength requirements of the project. The best mix ratio is determined through multiple tests to ensure that the performance of the concrete meets the design requirements; (3) Mixing: Pour sand and cement into a mixer and dry mix them evenly. Then add the pre-wetted expanded clay and continue dry mixing for 1 to 2 minutes. Then, according to the designed water-cement ratio, slowly add water and continue mixing for 3 to 5 minutes to ensure that the mixture is uniform.

[0028] (4) Pouring: The mixed ceramsite concrete is transported to the construction site and poured into the mold. The pouring process should be carried out in layers, with each layer thickness controlled between 30 and 40 cm. A vibrating rod should be used to vibrate the concrete to remove bubbles and improve its density.

[0029] The following are the mix proportions required for concrete of different strength levels: As a new type of environmentally friendly high-quality building material, ceramsite concrete has the following precautions in its use: (1) The materials used must meet the requirements Ceramic aggregate concrete has many advantages, but to better play these advantages requires the cooperation of various materials and processes. Therefore, when using ceramsite concrete, we must pay attention to using materials that meet the quality requirements. All materials must not only be selected according to the design requirements, but also be inspected and accepted when entering the site to ensure that the density, thermal conductivity, strength and density meet the quality requirements before they can be used; (2) The surface layer can only be constructed after the cushion layer is maintained In the construction of ceramsite concrete, there are multiple layers of construction. The surface layer is the top surface layer. Before construction, it is important to pay attention to the maintenance of the cushion layer below it, and it needs to be maintained at room temperature for three days before construction. In addition, during the construction of the surface layer, the cushion layer must be covered with protective materials. It is even more forbidden to stir the mortar, place paint buckets and other heavy objects and debris on the cushion layer. (3) Pay attention to controlling water usage during on-site mixing Compared with ordinary concrete, ceramsite concrete has a small surface density and large voids, so it has strong water absorption. Therefore, during construction, attention should be paid to mixing on site, and the amount of water used should be strictly controlled during mixing. In addition, after paving the ceramsite concrete, it should be compacted with mechanical vibration.

[0030] The points mentioned above are all things that require special attention when using expanded clay concrete, because expanded clay concrete is usually an important material used in the construction of construction projects. Therefore, during construction, it is necessary not only to purchase high-quality concrete by referring to the expanded clay concrete price list, but also to pay attention to various details during the construction process to ensure construction quality.

[0031] Environmental protection treatment during the production of ceramsite: 1. Waste heat recovery and flue gas treatment The heat source for drying wet pellets in this system comes from two sources: one is the heat collected by the cooling machine for cooling ceramsite; the other is the waste heat from the tail gas generated during the roasting process of the rotary kiln, which not only makes full use of the waste heat of the production line, but also saves the heat source supply of the drying section. The tail gas discharged by the dryer is collected centrally and then discharged after comprehensive treatment of dust removal and desulfurization.

[0032] 2. Environmentally friendly process Environmental protection measures for this production line include Figure 1 : 2.1 Wastewater The sources of process wastewater are flushing wastewater, laboratory wastewater and a small amount of domestic sewage; the excess wastewater can be reused in the production line as production water. The process wastewater generated by the system can be well utilized in an integrated manner.

[0033] 2.2 Waste residue This production line uses gypsum desulfurization, and the waste residue produced is a small amount of desulfurization gypsum. After dehydration, it can be used as raw material for this production line, or supplied to other projects in the park to achieve resource recycling.

[0034] During the production process of this production line, a small amount of unqualified balls screened out and dust collected from various dust removal points can be returned to the raw material pretreatment section through the return device for recycling.

[0035] 2.3 Exhaust gas The flue gas discharged from the rotary kiln is treated with SNCR denitrification and then dusted before being sent to the heat exchange device; the tail gas after heat exchange is sent to the special dryer with clean air after the SCR denitrification device; the flue gas cooled by the vibration cooler is sent to the special dryer together with the clean air after heat exchange for raw material ball drying after dust removal. The tail gas discharged from the dryer meets the emission standards after dust removal, wet desulfurization, and wet electrostatic dust removal.

[0036] 2.4 Noise The noise comes from induced draft fans, desulfurization towers, and air compressors. The noise prevention measures taken are to select high-efficiency, stable, and low-noise equipment from the source, and to install silencers and noise reduction devices on equipment with higher noise levels. Shock-absorbing bases are used for fans, and flexible joints are used at connections; compensating joints are installed on air ducts to reduce the noise generated by vibration, and basic shock absorption is used for cooling tower noise.

[0037] Production line automation control description In terms of production line automation control, this project can ensure efficient and stable operation of the production line and realize flexible automated production of products through the intelligent control architecture of centralized management, decentralized control, information sharing and data analysis. Centralized management can ensure that system managers can uniformly monitor and control each subsystem; decentralized control can maintain the independence of each system and improve the ability to avoid system risks; information sharing can enable multi-level managers to share operation information and discover and solve problems in a timely manner; data analysis can analyze and model the feedback data through the information feedback of multiple sensors on the production line, combined with the characteristics of the control system, and establish a process algorithm model to achieve intelligent operation and maintenance guarantee for the entire system.

[0038] The technology of preparing high-performance light aggregate with waterfall rotary kiln combines Western European technology with domestic rotary kiln manufacturing and use experience. It overcomes the disadvantages of traditional solid waste light aggregate technology, such as small solid waste addition, high energy consumption cost, poor light aggregate quality, low degree of automation, and substandard environmental protection disposal, by greatly optimizing production processes and core equipment, adopting production line waste heat recycling measures, using production line PLC / DCS centralized control system, and equipped with a complete flue gas and odor treatment system. It has great technical advantages and market value. This technology improves the production process of solid (hazardous) waste light aggregate, and proposes the technical route of "low temperature drying + high temperature roasting + rapid cooling". After the raw materials are mixed and granulated, they are dried at low temperature at 200°C in the fluidized dryer outside the kiln using the waste heat of the production line. The dried pellets enter the kiln, and the ceramsite light aggregate is roasted at a high temperature of more than 1100°C. The exhaust gas out of the kiln is quickly cooled within 2 seconds after dust removal and used in the pellet drying section. This technology and complete set of equipment are compatible with the production of all lightweight aggregate performance products on the market, especially for raw materials with complex components and sources, such as municipal sludge, lake and river sludge, bottom mud, red mud solid waste, as well as chromium slag, waste incineration fly ash, and pickling sludge hazardous waste.

[0039] The use of this technology to treat and dispose of solid waste has the following significant advantages: 1. Large solid waste consumption and significant synergistic treatment effect This technology can collaboratively process different types of bulk industrial solid waste and hazardous waste, and is widely used in the treatment and disposal of red mud, (inferior) fly ash, coal gangue, (gold, iron, molybdenum) tailings, river sludge, municipal sludge, gasification slag, engineering slag, general solid waste, as well as fly ash, cyanide-containing waste residue, chromium mud, and HW17 sludge. Due to the wide applicability of technical raw materials, project construction companies can comprehensively dispose of waste residues, sludge, silt, contaminated soil and other solid wastes of large enterprises or industrial parks, thereby collecting part of the disposal fee and improving the comprehensive income level of the project.

[0040] 2. The equipment is highly efficient and energy-saving, and the unit product production cost is reduced by more than 1 / 2. The core roasting equipment, the waterfall rotary kiln, adopts a unique structural design. The fly ash and sludge light aggregate production line constructed by the company has been identified by the National Building Materials Industry Cement Energy Efficiency and Environmental Protection Evaluation Inspection and Testing Center as having a heat consumption of about 41 kg of standard coal per ton of light aggregate. Compared with the heat consumption of 90 kg of standard coal per unit of light aggregate in the traditional plug-in rotary kiln, the energy saving effect is as high as more than 50%, which has great energy-saving and consumption-reducing demonstration significance. The production line is equipped with a waste heat recycling device, which extracts the heat from the kiln exhaust gas and uses it for drying the raw material balls, so that the drying section does not require an external heat source; the waste heat of the cooler is also recovered. After heat balance calculation, in addition to drying the balls, it can also be used for workshop heating and bathing purposes, realizing the full and efficient utilization of the production line's heat energy to the greatest extent.

[0041] 3. High degree of homogeneity of finished products Homogeneity is an important assessment indicator for lightweight aggregate used in structural concrete. In terms of material homogenization, this technology ensures high homogeneity of the finished product through the equipment and process combination of "vertical turbulent mixing equipment with a mixing homogeneity of 99.8% in 90 seconds + fully automatic extrusion granulation equipment + vibrating fluidized bed drying equipment + waterfall rotary kiln roasting equipment with a lifting and mixing device, and a proprietary cooler with both rapid and slow cooling functions". According to the product test results of the fly ash and sludge lightweight aggregate production lines that have been put into production, the barrel compressive strength of lightweight aggregate can reach more than 20MPa, and the diversified and differentiated product market needs of downstream customers can be met by adjusting the raw material ratio and process parameters, and one production line can meet the functional requirements of different products.

[0042] 4. Obvious environmental advantages The technology does not discharge wastewater or waste residue, and wastewater can be recycled within the production line, while waste residue can be used as raw materials and then re-entered into the production process. In terms of flue gas emissions, according to the combination of different raw materials and fuel components, it is equipped with complete desulfurization, denitrification, and dust removal facilities to meet the requirements of ultra-low emission environmental protection standards; in the treatment of solid waste that can produce dioxins, the production line uses a process combination of "low-temperature drying + high-temperature roasting + rapid cooling" to prevent the generation and re-synthesis of dioxins.

[0043] 5. The production line has a high degree of intelligent control. This technology can form a distributed control system using the ideas of PLC or DCS centralized management, decentralized control and information sharing. The system has monitoring alarm, remote diagnosis and data archiving functions, and can achieve the ultimate remote cloud maintenance function. Only 3 people are required for each shift of the production line. The waterfall rotary kiln adopts an automatic temperature and fire control device, which can monitor the situation in the kiln at all times, greatly reducing the reliance on the experience of the fire watcher, and providing a guarantee for the continuous and efficient production of the production line.

[0044] The project highlights are as follows: (1) This project is currently the largest high-performance lightweight aggregate project under construction in China with the highest level of intelligent control, the lowest production energy consumption, and the ability to achieve ultra-low emissions.

[0045] (2) The raw materials of the project are all solid waste, the raw materials are coal gangue, supplemented by some by-product industrial waste slag of the group. The ceramsite industry is the first in China to use an improved cooling machine that can utilize waste heat in stages, making the production line more energy-efficient.

[0046] (3) The product is a "one machine with multiple functions" and can be used to prepare a variety of ultra-light expanded clay, biological filter materials, and high-strength, high-homogeneity expanded clay products.

[0047] (4) The production process is clean and pollution-free, the raw material transportation and flue gas flow are fully sealed, and no wastewater or waste residue is discharged during the production process.

[0048] (5) The project adopts a DCS centralized control system, and is committed to creating a visual, adaptive smart factory through automation, 5G network, and robot inspection assistance. The construction period of the first phase of the project (annual production of 400,000 m³ of high-performance lightweight aggregate) is 1 year. After the completion of the project, it will be of great significance to realize the comprehensive utilization of solid waste in the Huangling mining area, promote economic development, promote the green transformation of the coal industry, and guide the equipment innovation and process upgrading and optimization of the ceramsite industry.

[0049] like Figure 3 As shown: The process of this project includes the following processes.

[0050] 1. The engineering waste soil is transported to the storage bin by a dedicated sealed conveying equipment; the HW17 industrial sludge is transported to the sludge storage by a transport vehicle, and then sent to the shaftless screw conveyor by a remote-controlled grab, and then sent to the drying equipment after impurities are removed; the drying equipment uses the waste heat of the production line flue gas to perform preliminary drying on the sludge, and then sends it to the sludge storage bin to reduce its moisture content for standby use.

[0051] 2. After different materials are measured in proportion, they are mixed in the vertical turbulent mixer. The mixed materials are evenly fed to the disc granulator through the steady flow control system. The formed lightweight aggregate blanks are preheated and dried in the vibrating fluidized bed dryer.

[0052] 3. The dried lightweight aggregate body enters the waterfall rotary kiln and is roasted at high temperature to become the finished lightweight aggregate. It is then cooled to room temperature by a vibrating fluidized bed cooler and transported to the grading screen for screening by an elevator.

[0053] 4. The fuel of the production line is rice husk powder; the exhaust gas generated during the roasting process exchanges heat into clean air through a heat exchanger and is supplied to the vibrating fluidized bed dryer for preheating and drying of the lightweight aggregate blank.

[0054] 5. The exhaust gas after heat extraction is transported to the original flue gas treatment system interface of Party A's factory area and discharged after comprehensive treatment by the flue gas treatment system.

Claims

1. A method for preparing ceramsite concrete, characterized in that: Here are the steps: S1: Raw material preparation: prepare graphite slag, gold slag, iron slag and other powdered raw materials as raw materials for ceramsite, and also prepare cement, sand, clean water and admixtures; S2: Transportation and processing of ceramsite raw materials: Pump them to the raw material warehouse for storage, and ensure sealed transportation throughout the process without dust leakage. If there is municipal sludge plastic raw material, it needs to be transported to the sludge buffer warehouse for standby via special conveying equipment, and ensure sealed micro-negative pressure transportation throughout the process without odor leakage; S3: Mixing of ceramsite ingredients: graphite slag, gold slag, iron slag and other powdered raw materials are sent to the top of the mixer by a closed screw conveyor for metering control; municipal sludge and other plastic raw materials are pumped to the top of the mixer for standby use; S4: Ceramic granulation and drying: The high-speed mixed materials are sent to the granulator for granulation. The raw material balls after granulation are sent to a special dryer for drying. The dried balls are sent to a waterfall rotary kiln for roasting. S5: High-temperature roasting of ceramsite: After the dry material balls enter the kiln, the waterfall rotary kiln rotates at a preset speed. The temperature in the kiln is adjusted by the burner. The relevant operation accuracy is ±5°C. The remote operator in the central control room monitors and adjusts the air supply and fuel supply in real time according to the flame monitoring system and the burner control system. After the material balls are fully roasted and melted in the waterfall kiln, they fall into the vibrating fluidized bed cooler for cooling. The cooled ceramsite is sent to the finished product screen, and different specifications are screened according to market demand and packaged and sent to the finished product warehouse for storage; S6: Mix the prepared ceramsite with cement, sand, clean water and admixtures. Pour the sand and cement into a mixer and dry mix them evenly. Then add the pre-wetted ceramsite and continue dry mixing for 1 to 2 minutes. According to the designed water-cement ratio, add water and continue stirring for 3 to 5 minutes. The mixture is uniform. Transport the mixed ceramsite concrete to the construction site and pour it into the mold. The pouring process should be carried out in layers. The thickness of each layer should be controlled between 30 and 40 cm. Use a vibrating rod to vibrate to remove bubbles in the concrete and increase the density. Finally, ceramsite concrete is obtained.

2. The method for preparing ceramsite concrete according to claim 1, characterized in that: After high-temperature roasting of S5, waste heat is recycled and flue gas is treated. The drying heat source comes from two directions. One is the heat collected by cooling the ceramsite in the cooler; the other is the waste heat of tail gas generated during the roasting process of the rotary kiln. The tail gas discharged by the dryer is collected centrally and then discharged after comprehensive treatment of dust removal and desulfurization.

3. The method for preparing ceramsite concrete according to claim 2, characterized in that: The waste heat recycling device extracts the heat from the kiln exhaust gas and uses it for drying the raw material balls, so that the drying section does not require an external heat source; the waste heat from the cooler is also recovered, and after heat balance calculation, in addition to ball drying, it can also be used for workshop heating and bathing purposes.

4. The method for preparing ceramsite concrete according to claim 1, characterized in that: The flue gas discharged from the rotary kiln in S5 is subjected to SNCR denitration treatment and then dust-removed and sent to the heat exchange device; the tail gas after heat exchange is sent to a special dryer with clean air after the SCR denitration device; the flue gas cooled by the vibration cooler is sent to a special dryer with clean air after dust-removal and heat exchange for drying raw material balls.

5. A method for preparing ceramsite concrete according to any one of claims 1 to 4, characterized in that: The environmental protection process includes the treatment of waste water, waste residue, waste gas and noise.

6. The method for preparing ceramsite concrete according to claim 5, characterized in that: The sources of the process wastewater are flushing wastewater, laboratory wastewater and a small amount of domestic sewage; Excess wastewater can be recycled to the production line as production water.

7. The method for preparing ceramsite concrete according to claim 5, characterized in that: The production method adopts gypsum desulfurization, and the waste residue produced is a small amount of desulfurized gypsum, which can be used as the raw material of the production line after dehydration treatment.

8. The method for preparing ceramsite concrete according to claim 5, characterized in that: The exhaust gas is discharged in compliance with emission standards after dust removal, wet desulfurization and wet electrostatic dust removal.

9. The method for preparing ceramsite concrete according to claim 5, characterized in that: The noise comes from induced draft fans, desulfurization towers, and air compressors. The noise prevention measures taken are to select high-efficiency, stable, and low-noise equipment from the source, and to install silencers and noise reduction devices on equipment with higher noise levels. Shock-absorbing bases are used for fans, and flexible joints are used at connections; compensating joints are installed on air ducts to reduce the noise generated by vibration, and basic shock absorption is used for cooling tower noise.

10. The method for preparing ceramsite concrete according to claim 1, characterized in that: The suitable ceramsite content in S6 is 40% to 60%, and the ratio of cement to sand is adjusted according to the engineering strength requirements. The best mix ratio is determined through multiple tests. The selection of raw materials in S1 includes ceramsite: ceramsite that meets the specifications is selected, generally ceramsite with a particle size between 4 and 20 mm is selected, and the ceramsite is pre-wetted in advance; Cement: Ordinary Portland cement and other types of cement suitable for concrete; Sand: Choose medium-coarse sand, and the mud content should be controlled below 5%; clean water cannot contain substances harmful to concrete; admixtures include water reducing agents and expansion agents, which should be added as needed.

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