Process for preparing light high-strength ceramic pellets from waste incineration fly ash, oil sludge type hazardous waste and general solid waste

Abstract

The application discloses a kind of processes for preparing light high-strength ceramic pellets by waste incineration fly ash, oil sludge hazardous waste and general solid waste, and the steps are as follows: S1, pretreatment, fly ash is gradually water-washed, stirred and solid-liquid separated by adding water, and dried to reduce the moisture content to below 3%; the oil sludge hazardous waste is sequentially sorted, crushed, scattered and multi-stage screened, so that the undersize material is powdery substance; S2, the pretreated fly ash and oil sludge hazardous waste are mixed and proportioned, and the moisture content of the mixed material is controlled to be 18-23%; S3, the ceramic green body is two-stage dried to reduce the moisture content to 3-5%; the strength of the two-stage dried ceramic green body is greater than 2 MPa; S4, the two-stage dried ceramic green body is sent to the calcining system for calcination, and the light high-strength ceramic pellets are obtained after cooling. The application cooperatively disposes domestic waste incineration fly ash, oil sludge hazardous waste and general solid waste fly ash, realizes the comprehensive utilization of solid waste hazardous waste to produce green building materials, and truly practices the energy-saving and emission-reducing, green and low-carbon environmental protection concept.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resources and environment, and particularly relates to a process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge type hazardous waste and general solid waste. BACKGROUND

[0002] The waste incineration fly ash is a kind of powder material with light specific gravity and small particle size, which is mainly collected from the flue gas pipeline, flue gas purification device, cyclone separator and bag-type dust collector during the incineration of household garbage. With the continuous improvement of flue gas purification level, the flue gas discharged into the atmosphere is cleaner and cleaner, and the composition of the fine particles (fly ash) trapped and captured by the purification system is more and more complex and harmful. How to efficiently and environmentally dispose of hazardous waste is one of the current research hotspots, and on the basis of harmless treatment, resource utilization is the development direction of solid waste disposal.

[0003] The general solid waste and the oil sludge type hazardous waste are both environmental pollutants with large production quantity, large historical stock quantity and high treatment difficulty. Especially, the fly ash, oil sludge, tank cleaning sludge and oil sludge residue contain high content of harmful substances such as petroleum hydrocarbon, heavy metal and dioxin.

[0004] In the existing disposal and resource utilization scheme of fly ash, other general solid waste such as waste glass, municipal sludge, industrial waste residue, low-grade shale and perlite can be cooperated to a certain extent. This also becomes a new direction and way for the current fly ash and other bulk solid waste cooperative disposal.

[0005] Since incineration fly ash contains Si, Al, Ca, Fe, Na, K and other components, similar to the components of the ceramic matrix raw materials, using incineration fly ash to prepare ceramsite has become one of the resource utilization ways of incineration fly ash. The incineration fly ash used is mainly raw incineration fly ash or incineration fly ash pretreated by water washing and leaching. For example, Chinese Patent Publication No. CN113213191A discloses a method for preparing ceramsite using waste incineration fly ash and ceramsite prepared thereby. The method uses waste incineration fly ash as raw material, adds limestone and clay, fly ash, sludge and other high-silicon substances to adjust the proportion of the main components of the ceramic raw material, and then performs balling, drying and high-temperature roasting to obtain ceramsite with excellent performance and harmful substance content meeting the standards. Chinese Patent Publication No. CN101357840A discloses a method for manufacturing a waste incineration fly ash ceramsite without firing. The method uses waste incineration fly ash as the main raw material, first adds a reagent for heavy metal stabilization treatment, then mixes with Portland cement and fly ash, and performs granulation on a disc granulator. After adding cement or lime to form a stable outer shell, curing is performed to obtain a non-fired fly ash ceramsite. Chinese Patent Publication No. CN109721266A discloses a method for preparing a waste incineration fly ash waste utilization sintered ceramsite. The method includes: mixing and grinding waste incineration fly ash, glass powder, dried municipal sludge and pore-forming agent to obtain a mixed powder; adding water to the mixed powder to age and granulate to obtain a ceramsite core raw material; mixing glass powder, dried municipal sludge and correction material and adding water to stir to obtain a ceramsite coating material; covering the ceramsite core raw material with a layer of ceramsite raw material coating to obtain a ceramsite raw material; drying the ceramsite raw material at 105°C for 5-12h, pre-burning at 350-650°C for 10-60min, sintering at 1050-1300°C for 20-100min, and water or air cooling to obtain a fly ash waste utilization sintered ceramsite with a compressive strength of 10MPa or more and a bulk density of 900kg / m3 or less. The method provided by the invention can effectively solidify fly ash heavy metals, achieve harmless treatment and good product quality.

[0006] Chinese patent publication CN113387715A discloses a method for preparing fly ash ceramsite with low sintering temperature. The fly ash obtained from waste incineration, diatomite, soil and composite fluxing agent are dried at 105°C and crushed respectively, then the fly ash is washed with water, then the diatomite is mixed with the fly ash and hydrothermally reacted at 160°C for 12h, finally the fly ash mixture after hydrothermal reaction is mixed with soil and composite fluxing agent, rolled into pellets, pre-sintered at 350°C, and sintered at 900-1000°C to obtain ceramsite with a bulk density of 800kg / m3 and a 5MPa strength. Before the fly ash mixture is pelletized and sintered, the fly ash mixed with diatomite is subjected to hydrothermal pretreatment. This operation reduces the content of calcium oxide in the fly ash mixture, thereby reducing the sintering temperature of the fly ash, so that the fly ash ceramsite can be sintered at a low temperature of 900-1000°C. At the same time, the hydrothermal pretreatment process generates calcium silicate hydrate, which can generate wollastonite during the sintering of fly ash ceramsite, and wollastonite can improve the mechanical strength of lightweight aggregate ceramsite.

[0007] Chinese patent publication CN115745648A discloses a method for preparing ceramsite using household waste incineration fly ash and electrolytic manganese residue. A certain amount of fly ash is pretreated by water washing for 10-60min, then soaked and dried. The electrolytic manganese residue, fly ash and fly ash are ground and crushed. After grinding, a certain amount of electrolytic manganese residue, fly ash and fly ash are mixed in a certain proportion and stirred thoroughly. The mixed material (fly ash: electrolytic manganese residue: fly ash mixed at a ratio of 1:5:4) is put into a pelletizer for pelletization. The prepared pellets are preheated at 650°C, then sent into a muffle furnace and heated to 1150°C for calcination to obtain 15MPa ceramsite. The invention uses household waste incineration fly ash and electrolytic manganese residue as carriers to prepare ceramsite, which not only reduces the cost of ceramsite, but also solidifies / stabilizes the heavy metals in household waste incineration fly ash and electrolytic manganese residue, achieving the purpose of "waste treatment with waste, turning waste into treasure" and energy saving and emission reduction, realizing the win-win purpose of social environment and economy.

[0008] Chinese patent publication CN116496071A discloses a fly ash low-carbon ceramsite, its preparation method and production system. First, the fly ash is treated by dechlorination elution with landfill leachate, then the dechlorinated fly ash is dewatered, mixed with other raw materials, pelletized, sintered at 1200-1250°C for 30min to obtain low-carbon fly ash ceramsite. The invention combines fly ash leachate dechlorination technology, uses fly ash high-temperature sintering process to realize dechlorination, organic fly ash, dioxin and other pollutant decomposition, and completely solidifies the heavy metals in fly ash using cement or concrete, finally realizes fly ash low-carbon resource utilization and landfill leachate low-cost treatment.

[0009] However, the present inventors have found that the above prior art at least has the following technical problems:

[0010] (1) Waste incineration fly ash is mixed with kaolin, fly ash and other high-silicon materials to make ceramsite which can be applied in water treatment or building materials field. However, due to the difference in raw materials and pretreatment methods, the selection and material ratio of fly ash and raw materials will become difficult to control.

[0011] (2) Fly ash is not washed, and the inorganic salt components, especially chlorides, will greatly affect the quality performance of ceramsite. The strength of ceramsite is poor, and the solidification effect of heavy metals in fly ash is unstable, which is easy to volatilize under high temperature conditions and cause pollution, limiting its application.

[0012] (3) Fly ash is not treated and directly mixed with fly ash, Portland cement and heavy metal stabilizer to prepare unfired ceramsite. Although the heavy metal leaching meets the standard, the strength of the obtained ceramsite is only 8 MPa, and the unfired method limits the improvement of ceramsite strength.

[0013] (4) Fly ash is washed to remove chlorine, dried, and then mixed with other materials after hydrothermal reaction to make ceramsite. Although laboratory-level lightweight ceramsite can be obtained, the raw material ratio is complex, and the selection and material ratio of fly ash and raw materials will become difficult to control in the industrial application process. In addition, the rolling granulation and calcination temperature of only 900-1000℃ directly affect the improvement of the cylinder pressure strength of ceramsite.

[0014] (5) Fly ash is treated by leaching with landfill leachate or water to remove chlorine, and then mixed with other raw materials after dewatering treatment to make ceramsite. Although low-carbon fly ash ceramsite can be prepared, the raw material ratio is complex, and the selection and ratio of fly ash and raw materials are difficult to control. In addition, the sintering temperature of 1250℃ leads to high energy consumption, and the performance of sintered ceramsite is not studied, so it cannot be determined whether the sintered ceramsite can meet the established requirements.

[0015] (6) Fly ash is treated by water washing and drying, and then ground and mixed with other materials to make ceramsite. Pre-burning at a high temperature of 650℃ is easy to cause damage to the ceramsite green body, resulting in an increase in the breakage rate of finished products. SUMMARY

[0016] The present application provides a process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge hazardous waste and general solid waste, which improves the types and proportions of materials, optimizes the granulation process, and replaces high-temperature pre-burning with two-stage drying to produce lightweight high-strength ceramic granules at a lower firing temperature. In addition, the entire process makes full use of high-temperature flue gas waste heat for drying of material balls, improving system thermal efficiency. The non-condensable gas from the drying section is used as fuel in the firing system, saving natural gas consumption and reducing system energy consumption. In particular, through resource utilization, waste incineration fly ash, oil sludge hazardous waste and general solid waste fly ash are co-disposed, achieving the goal of comprehensive utilization of solid waste and hazardous waste to produce green building materials, truly practicing the concept of energy saving, emission reduction and green low-carbon environmental protection, and having important practical significance.

[0017] The present application is implemented as follows: a process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge hazardous waste and general solid waste, comprising the following steps:

[0018] S1, pretreatment of fly ash and oil sludge hazardous waste

[0019] The pretreated fly ash and oil sludge hazardous waste are mixed in proportion, and the water content of the mixed material is controlled to be 18-23%;

[0020] The impurities in the oil sludge hazardous waste are first removed, then crushed and dispersed, and then the crushed material is subjected to multi-stage screening so that the undersize material is in powder form;

[0021] S2, mixing and batching

[0022] The pretreated fly ash and oil sludge hazardous waste are mixed in proportion, and the water content of the mixed material is controlled to be 18-23%;

[0023] S3, two-stage drying of ceramic green body

[0024] The mixed and batched material is extruded to form a ceramic green body, which is then subjected to one-stage indirect drying to reduce the water content of the ceramic green body to 10-15%, and then subjected to two-stage direct drying to reduce the water content of the ceramic green body to 3-5%; the strength of the ceramic green body after two-stage drying is > 2 MPa;

[0025] S4, firing

[0026] The ceramic green body after two-stage drying is fed into a firing system rotary kiln for calcination, and then cooled to obtain lightweight high-strength ceramic granules.

[0027] Preferably, the specific process for pretreating fly ash is as follows:

[0028] The fly ash after grinding and screening is first added to a first elution reactor, water is added for water washing and stirring, the fly ash and water are added in a ratio of 1:2-1:6, preferably 1:3, the water washing reaction time is 10-60 min, preferably 30 min, and then solid-liquid separation is performed; the fly ash cake after the first solid-liquid separation is added to a second elution reactor, water is added for water washing and stirring, the fly ash and water are added in a ratio of 1:2-1:6, preferably 1:3, the water washing reaction time is 10-60 min, preferably 30 min, and then solid-liquid separation is performed; the fly ash cake after the second solid-liquid separation is added to a third elution reactor, water is added for water washing and stirring, the fly ash and water are added in a ratio of 1:2-1:6, preferably 1:3, the water washing reaction time is 10-30 min, preferably 15 min, and then solid-liquid separation is performed; the fly ash cake after the third solid-liquid separation is placed in a fly ash drying system at 100-110°C for drying, so that the water content is reduced to below 3%.

[0029] Preferably, the specific process of the oil sludge type hazardous waste pretreatment is as follows:

[0030] The oil sludge type hazardous waste is first subjected to primary separation to remove impurities, and then the material is crushed and dispersed; the crushed material is first subjected to primary screening to remove block-shaped materials with a particle size of 5-10 cm, and then subjected to secondary screening to remove crushed materials with a particle size of 2-5 mm, so that the undersize materials are all powdery materials with a particle size of ≤10 mesh.

[0031] Preferably, the specific process of the mixed batching is as follows:

[0032] The pretreated fly ash and oil sludge type hazardous waste are mixed and batched according to the set proportion through a metering and weighing system;

[0033] When three components are mixed and batched, the fly ash: fly ash: bentonite or kaolin = 10%-30%: 30%-70%: 5%-15%;

[0034] When four components are mixed and batched, the fly ash: fly ash: oil sludge type hazardous waste: bentonite or kaolin = 10%-30%: 10%-30%: 30%-50%: 5%-15%.

[0035] Preferably, the heat source of the first indirect drying is one of steam, heat conducting oil or other heat conducting medium; the mode of the first indirect drying is one of rotary kiln type jacket drying, membrane type wall type jacket drying and crawler type drying.

[0036] Preferably, the second direct drying is belt drying, and the heat source of the second direct drying can be one of natural gas, hot flue gas and hot air.

[0037] Preferably, the calcination temperature is 950-1100 DEG C, and the sintering time is 30-60 min; the cylinder compressive strength of the lightweight high-strength ceramic aggregate is > 15 MPa, and the bulk density is 650-850 kg / m 3 .

[0038] Preferably, the high-temperature flue gas generated in the sintering process is first subjected to SNCR denitration in the rotary kiln, the denitration reducing agent is selected from urea, the urea solution concentration is 10%, the flue gas after denitration is first subjected to high-temperature dust removal, then subjected to heat exchange with the heat conducting oil furnace to recover waste heat, and then subjected to quenching, dioxin removal, dry acid removal, bag dust removal, two-stage wet acid removal, and flue gas reheating before being discharged.

[0039] Preferably, the waste gas generated in the fly ash pretreatment drying and the two-stage drying of the ceramic green body is condensed, the condensed waste water is sent to a sewage station for treatment, and the non-condensable gas containing oil gas is sent into the sintering system as fuel and burned off.

[0040] A lightweight high-strength ceramic aggregate is prepared by using the above process.

[0041] The present application has the advantages and positive effects that:

[0042] The present application prepares lightweight high-strength ceramic aggregate at a lower sintering temperature by improving the types and proportions of materials, optimizing the granulation process, and replacing high-temperature pre-sintering with two-stage drying. In addition, the whole process fully utilizes the waste heat of high-temperature flue gas for drying of material balls and the like, thereby improving the system thermal efficiency. On the other hand, the non-condensable gas in the drying section is introduced into the sintering system as fuel, thereby saving the amount of natural gas and reducing the system energy consumption. In particular, through resource utilization, the household garbage incineration fly ash, oil sludge hazardous waste and general solid waste fly ash are disposed of, the purpose of comprehensive utilization of solid waste and hazardous waste to produce green building materials is achieved, the energy saving and emission reduction, green and low-carbon environmental protection concept is truly practiced, and it has important practical significance. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flow chart of the zero-emission system for disposing volatile harmful components at the kiln head provided by the embodiments of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] Please refer to Figure 1 The embodiment of the present application provides a process for preparing lightweight high-strength ceramic granules from household garbage incineration fly ash, oil sludge hazardous waste and general solid waste, comprising the following steps:

[0047] S1, pretreatment of fly ash and oil sludge hazardous waste

[0048] The fly ash after grinding and screening treatment is first added to a first elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:3, the water washing reaction time is 30 min, and then the fly ash is subjected to solid-liquid separation in a solid-liquid separator; the fly ash cake after the first solid-liquid separation is added to a second elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:3, the water washing reaction time is 30 min, and then the fly ash is subjected to solid-liquid separation in a solid-liquid separator; the fly ash cake after the second solid-liquid separation is added to a third elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:3, the water washing reaction time is 15 min, and then the fly ash is subjected to solid-liquid separation in a solid-liquid separator; the fly ash cake after the third solid-liquid separation is placed in a fly ash drying system at 105℃ for drying, so that the water content is reduced to below 3%, and the pretreated fly ash is sent to a mixing and batching section by a screw conveyor.

[0049] During fly ash water washing, the pretreatment of fly ash can be flexibly completed by adjusting the solid-liquid ratio of fly ash water washing, the water washing time and the water washing times according to the fly ash analysis data range.

[0050] The waste gas generated during fly ash drying is condensed, the condensed wastewater is sent to a sewage station for treatment, and the non-condensable gas containing oil gas is sent into the firing system as fuel and burned off. The generated non-condensable gas is introduced into the firing system for combustion, which not only solves the safety risk caused by oil gas accumulation during drying, but also replaces part of the natural gas and saves the amount of fuel gas, truly realizing energy saving and consumption reduction.

[0051] The oil sludge type hazardous waste is first sorted into one level to remove sundries, and then is fed into a crusher by a forklift or a travelling crane to crush and scatter the material; after crushing, the material is sent to a first screening system by a conveying mechanism to screen out the blocky material with a particle size of about 5-10 cm, and then is sent to a second screening system to screen out the crushed material with a particle size of 2-5 mm, so that the undersize material is all in a powder form, the particle size of the powder material is ≤10 mesh, and the pretreated oil sludge type hazardous waste is sent to a mixing and batching section by a belt conveyor.

[0052] The oil sludge type hazardous waste includes one or more of oil sludge pyrolysis residue, oil sludge on the ground and oil sludge after hot washing.

[0053] S2, mixing and batching

[0054] The pretreated fly ash and oil sludge type hazardous waste are respectively conveyed to corresponding storage bins by a screw conveyor and a belt conveyor, and then are mixed and batched according to a set proportion by a metering and weighing system.

[0055] When three components are mixed and batched, the fly ash: fly ash: bentonite (or kaolin) = 10%-30%: 30%-70%: 5%-15%; preferably, the fly ash: fly ash: bentonite (or kaolin) = 25%: 65%: 10%.

[0056] When four components are mixed and batched, the fly ash: fly ash: oil sludge type hazardous waste: bentonite (or kaolin) = 10%-30%: 10%-30%: 30%-50%: 5%-15%; preferably, the fly ash: fly ash: oil sludge type hazardous waste: bentonite (or kaolin) = 25%: 15%: 50%: 10% are mixed and batched.

[0057] The mixing and batching process needs to ensure that the material contains a certain amount of water, and the water content is generally controlled at 18-23%; preferably, the water content is controlled at 21%.

[0058] The water content of the ceramic particle green body can be automatically controlled flexibly by adjusting the amount of water added according to the water content of each material during mixing and batching.

[0059] S3, two-stage drying of ceramic particle green body

[0060] The mixed material is fed to the feeding port of the roller extrusion granulator by the elevator, and is obtained by high-strength extrusion granulation. To prevent the ceramic green body from exploding during the sintering process and to avoid the safety risk caused by the accumulation of oil gas volatilized from the ceramic green body during the sintering process, the ceramic green body is further sent into a first indirect drying system by the elevator for first indirect drying, so that the water content of the ceramic green body is reduced to 10-15%, preferably 12%. The heat source of the first indirect drying can be one of steam, heat conducting oil or other heat conducting medium, and is preferably heat conducting oil; the mode of the first indirect drying can be one of rotary kiln jacket drying, membrane wall jacket drying and crawler type drying, and is preferably membrane wall jacket drying. After the first indirect drying, the ceramic green body is fed into a second direct drying system by a conveying mechanism for second direct drying, so that the water content of the ceramic green body is reduced to 3-5%, preferably 3%. The second direct drying is preferably belt drying, and the heat source of the second direct drying can be one of natural gas, hot flue gas and hot air, and is preferably hot air. The hot air is supplied by a gas-fired hot blast furnace. The strength of the ceramic green body after the two-stage drying is >2MPa.

[0061] The efficiency of the second direct drying can be automatically adjusted by adjusting the amount of natural gas used by the hot blast furnace to adjust the temperature of the hot air according to the water content of the ceramic green body after the first indirect drying.

[0062] The exhaust gas generated in the two-stage drying process is condensed, and the condensed wastewater is collected and sent to a sewage station for treatment. The non-condensable gas containing oil gas is sent into the sintering system as fuel and burned off. The generated non-condensable gas is introduced into the sintering system for combustion, which not only solves the safety risk caused by the accumulation of oil gas during the drying process, but also replaces part of the natural gas and saves the amount of gas used, truly achieving energy saving and consumption reduction.

[0063] S4, sintering

[0064] The ceramic green body after the two-stage drying is sent into the sintering system rotary kiln for calcination, and then cooled to obtain lightweight high-strength ceramic aggregate.

[0065] The ceramic green body after the two-stage drying with a water content of only 3-5% is sent into the sintering system rotary kiln through the feeding system, and is calcined at 950-1100℃ for 30-60min. Preferably, it is calcined at 1030-1080℃ for 45min. After cooling, lightweight high-strength ceramic aggregate is obtained, and the cylinder compressive strength of the lightweight high-strength ceramic aggregate is >15MPa, and the bulk density is 650-850kg / m 3 .

[0066] The cylinder compressive strength of the lightweight high-strength ceramic aggregate can be flexibly controlled by adjusting the calcination temperature and sintering time of the sintering system; and the bulk density of the lightweight high-strength ceramic aggregate can be flexibly controlled by adjusting the material ratio, calcination temperature and sintering time.

[0067] The high-temperature flue gas generated in the sintering process is first subjected to SNCR denitration in the rotary kiln, urea is selected as the denitration reducing agent, the concentration of the urea solution is 10%, and the flue gas after denitration enters the flue gas treatment system, is subjected to high-temperature dust removal first, then exchanges heat with the heat conduction oil furnace to recover waste heat, and is then subjected to rapid cooling, dioxin removal, dry acid removal, bag dust removal, two-stage wet acid removal, and flue gas reheating before being discharged.

[0068] The removal efficiency of nitrogen oxides and acidic substances can be automatically adjusted by adjusting the injection amount of the medicament according to the concentration range in the flue gas.

[0069] The process of the present application is described in detail below with a specific example as follows:

[0070] The fly ash transported from the household garbage power plant is first subjected to three-stage countercurrent water washing to remove chlorine and salt with a solid-liquid ratio of 1:3, and then is subjected to drying treatment to reduce the moisture content of the fly ash to 3%. The oil sludge on the ground recovered in the plant area and the oil sludge residue generated in the pyrolysis process are subjected to one-stage separation and two-stage screening treatment, and then are sent to the mixing and batching section to be mixed with the pretreated fly ash and the binder (bentonite or kaolin). The types of mixed raw materials can be selected according to production requirements, and four-component and above mixing production or three-component mixing production can be performed. When three-component mixing is performed, the fly ash: fly ash: bentonite (or kaolin) is mixed at a ratio of 25:65:10, and when four-component mixing is performed, the fly ash: fly ash: oil sludge on the ground: bentonite (or kaolin) is mixed at a ratio of 25:15:50:10. The moisture content of the mixed material is controlled at 18-23% to ensure that the ceramic green body obtained by extrusion and granulation has good plasticity and does not stick during the aging process.

[0071] The ceramic green body after extrusion and granulation is first subjected to one-stage indirect drying to reduce the moisture content to 10-15%, and then is subjected to two-stage direct drying to reduce the moisture content to 3-5%, so as to ensure that the strength of the ceramic green body after two-stage drying is >2MPa, the material does not burst after entering the sintering system, and the breakage rate is reduced. The non-condensable gas generated in the two-stage drying process is sent into the sintering system as fuel and is burned off. The ceramic green body after two-stage drying enters the sintering system and is calcined at 950-1100℃ for 30-60min to obtain lightweight high-strength ceramic with a bulk density of 650-850kg / m 3 , and a cylinder pressure strength of >15MPa. The flue gas generated in the sintering system is treated by the flue gas treatment system to meet the GB18484-2020 standard before being discharged.

[0072] In summary, the present application prepares light-weight high-strength ceramic by improving material types and proportion, optimizing granulation process, replacing high-temperature pre-burning with two-stage drying and other means at a lower sintering temperature. In addition, the whole process makes full use of high-temperature flue gas waste heat for drying of material balls and the like, thereby improving the system thermal efficiency. On the other hand, the non-condensable gas in the drying section is introduced into the sintering system as fuel, thereby saving the amount of natural gas and reducing the system energy consumption. In particular, through the resource utilization approach, the household garbage incineration fly ash, oil sludge hazardous waste and general solid waste fly ash are synergistically disposed, the purpose of comprehensive utilization of solid waste and hazardous waste to produce green building materials is achieved, the energy saving and emission reduction and green low-carbon environmental protection concept are truly practiced, and it has important practical significance.

[0073] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge hazardous waste and general solid waste, characterized in that, It comprises the following steps: S1, fly ash and oil sludge type hazardous waste are pretreated The fly ash after grinding and screening treatment is added to a multi-stage elution reactor, and water is added step by step for countercurrent water washing, stirring and solid-liquid separation, dechlorination and desalination, and then the fly ash is dried to reduce the water content to below 3%. First, the impurities in the oil sludge type hazardous waste are selected out, and then the material is crushed and scattered, and then the crushed material is multi-stage screened to make the undersize material be powdery substance with particle size ≤10 mesh. S2, mixing and batching The pretreated fly ash and oil sludge type hazardous waste are mixed and batched by a metering and weighing system, and the fly ash: fly ash: oil sludge type hazardous waste: bentonite or kaolin = 10%-30%: 10%-30%: 30%-50%: 5%-15%; and the water content of the mixed material is controlled to be 18-23%. S3, two-stage drying of ceramic green body The mixed and batched material is extruded to form a ceramic green body, and then the ceramic green body is subjected to one-stage indirect drying to reduce the water content to 10-15%, and then the ceramic green body after one-stage indirect drying is subjected to two-stage direct drying to reduce the water content to 3-5%; the strength of the ceramic green body after two-stage drying is >2MPa. S4, firing The two dried ceramic green bodies are sent into a rotary kiln of a firing system for calcination, and then light-weight high-strength ceramic granules are obtained after cooling; the cylinder compressive strength of the light-weight high-strength ceramic granules is >15MPa, and the bulk density is 650-850kg / m 3 .

2. The process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge and other hazardous waste and general solid waste according to claim 1, characterized in that: The specific process of fly ash pretreatment is as follows: The fly ash after grinding and screening treatment is first added to a one-stage elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:2-1:6, the water washing reaction time is 10-60 min, and then solid-liquid separation is performed; the fly ash cake after one-stage solid-liquid separation is added to a two-stage elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:2-1:6, the water washing reaction time is 10-60 min, and then solid-liquid separation is performed; the fly ash cake after two-stage solid-liquid separation is added to a three-stage elution reactor, water is added for water washing and stirring, the addition amount ratio of fly ash to water is 1:2-1:6, the water washing reaction time is 10-30 min, and then solid-liquid separation is performed; the fly ash cake after three-stage solid-liquid separation is placed in a fly ash drying system at 100-110℃ for drying to reduce the water content to below 3%.

3. The process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge and other hazardous waste and general solid waste according to claim 1, characterized in that: The specific process of oil sludge type hazardous waste pretreatment is as follows: The oil sludge type hazardous waste is first subjected to one-stage separation to select out impurities, and then the material is crushed and scattered; the crushed material is first subjected to one-stage screening to screen out blocky material with particle size of 5-10 cm, and then subjected to two-stage screening to screen out crushed material with particle size of 2-5 mm, so that the undersize material is powdery substance.

4. The process for preparing lightweight high-strength ceramic according to claim 1, characterized in that: The heat source for one-stage indirect drying is selected from one of steam, heat conducting oil and other heat conducting medium; the mode for one-stage indirect drying is selected from one of rotary kiln type jacket drying, membrane type wall type jacket drying and crawler type drying.

5. The process for preparing lightweight high-strength ceramic according to claim 1, characterized in that: The two-stage direct drying is belt drying, and the heat source for two-stage direct drying can be selected from one of natural gas, hot flue gas and hot air.

6. The process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge hazardous waste and general solid waste according to claim 1, characterized in that: The calcination temperature is 950-1100℃, and the firing time is 30-60 min.

7. The process for preparing lightweight high-strength ceramic granules from waste incineration fly ash, oil sludge hazardous waste and general solid waste according to claim 1, characterized in that: The high-temperature flue gas generated in the sintering process is first subjected to SNCR denitration in the rotary kiln, urea is selected as the denitration reducing agent, the urea solution has a concentration of 10%, the flue gas after denitration is first subjected to high-temperature dust removal, then is subjected to heat exchange with a heat conduction oil furnace to recover waste heat, and then is subjected to quenching, dioxin removal, dry acid removal, bag dust removal, two-stage wet acid removal, flue gas reheating and finally is discharged.

8. The process for preparing lightweight high-strength ceramic according to claim 1, characterized in that: The waste gas generated in the fly ash pretreatment drying and the two-stage drying of the ceramic granule green body is condensed, the condensed waste water is sent to a sewage station for treatment, and the non-condensable gas containing oil gas is sent into the sintering system as fuel and is burned off.

9. A lightweight high-strength ceramic granule prepared by the process according to any one of claims 1-8.

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