Environment-friendly ceramsite prepared from fly ash solid hazardous waste sludge and preparation method of environment-friendly ceramsite

Abstract

The invention provides environment-friendly ceramsite prepared from fly ash solid hazardous waste sludge and a preparation method of the environment-friendly ceramsite, and belongs to the technical field of ceramsite. The invention discloses environment-friendly ceramsite prepared from fly ash and solid hazardous waste sludge. The environment-friendly ceramsite is prepared from the following raw materials in parts by weight: 28-38 parts of fly ash, 25-35 parts of solid waste sludge, 10-15 parts of fly ash, 5-10 parts of red mud, 3-7 parts of salt-containing waste, 3-10 parts of bentonite and 5-10 parts of a pyrolysis residue pore-forming agent. According to the environment-friendly ceramsite prepared from the fly ash solid hazardous waste sludge, solid waste recycling is achieved, and the ceramsite forming rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramsite, and particularly relates to environmentally friendly ceramsite prepared by utilizing fly ash, solid hazardous waste sludge, and a preparation method thereof. Background Art

[0002] The treatment of fly ash from garbage incineration is an important issue in the field of environmental protection. Fly ash contains a large amount of harmful substances such as heavy metals and dioxins. If not properly treated, it will cause serious pollution to the environment. Traditional fly ash treatment methods such as landfill not only occupy a large amount of land resources, but also have the risk of secondary pollution. In recent years, the use of fly ash to prepare ceramsite has become a research hotspot in the field of solid waste resource utilization, but the composition of fly ash itself cannot meet the needs of ceramsite firing.

[0003] Solid waste sludge refers to waste containing solid particulate matter generated during industrial production and domestic sewage treatment. It has the following characteristics: high water content, complex composition, and easy to cause secondary pollution. There are many ways to treat it, but landfill is still the main method at present. There are problems such as insufficient disposal capacity and backward disposal methods, resulting in the solid waste sludge not being treated in a standardized manner, which directly causes "secondary pollution" and poses a threat to the ecological environment.

[0004] Industrial waste salt refers to salt-containing waste generated during industrial production, mainly from the chemical, metallurgical, food processing, salt and other industries. The treatment of waste salt mainly relies on landfill and incineration. Although these methods can effectively reduce the amount of waste salt, they will also lead to resource waste and secondary pollution. The landfill of waste salt not only occupies land resources, but may also infiltrate into groundwater sources, causing soil and water pollution; while incineration will emit harmful gases and increase air pollution. Therefore, the resource utilization of waste salt has gradually become the focus of industry and social attention.

[0005] However, there is no technical report on the direct use of fly ash, solid waste sludge and salt-containing waste to jointly dispose of ceramsite. At the same time, the harmless treatment and resource utilization of these wastes have important environmental significance and economic value. In view of this, the applicant proposed to use fly ash, solid waste sludge and salt-containing waste to make ceramsite to realize solid waste resource utilization. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an environmentally friendly ceramsite prepared by directly utilizing fly ash, solid hazardous waste and sludge, so as to realize the resource utilization of solid waste and improve the forming rate of ceramsite, in view of the shortcomings of the prior art.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: an environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge, comprising the following raw materials in parts by weight: 28-38 parts of fly ash, 25-35 parts of solid waste sludge, 10-15 parts of fly ash, 5-10 parts of red mud, 3-7 parts of salt-containing waste, 3-10 parts of bentonite, and 5-10 parts of pyrolysis residue pore-forming agent.

[0008] Optionally, the pyrolysis residue pore-forming agent is at least one of coal tar residue pyrolysis residue, oily sludge pyrolysis residue, and paint residue pyrolysis residue.

[0009] Optionally, the solid waste sludge is at least one of domestic sludge, printing and dyeing factory sludge, paper mill sludge, and winery sludge.

[0010] Optionally, the solid waste sludge is a composition of domestic sludge, printing and dyeing sludge, and paper sludge, and the mass ratio of the three is (35-45):30:30, and the moisture content is less than 20%.

[0011] Optionally, the mass concentration of chloride ions in the salt-containing waste is less than 2%.

[0012] Optionally, the particle sizes of the fly ash, fly ash, red mud, and bentonite are all ≤100 mesh.

[0013] Optionally, the environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge is made of the following raw materials in parts by weight: 28-38 parts of fly ash, 25-35 parts of solid waste sludge, 10-15 parts of fly ash, 5-10 parts of red mud, 3-7 parts of salt-containing waste, 3-10 parts of bentonite, 5-10 parts of oily sludge pyrolysis residue, and the solid waste sludge is a composition of domestic sludge, printing and dyeing sludge, and paper sludge, and the mass ratio of the three is (35-45):30:30.

[0014] Optionally, the effective components and their mass percentage composition of the environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge are: SiO 2 47-54%, Al 2 O 3 20-25%, Fe 2 O 3 10-15%, CaO+MgO 8-12%, Na 2 O+K 2 O 2-4%.

[0015] The present invention also provides a preparation method of an environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge, comprising the following steps: S1: Mix fly ash, red mud and salt-containing waste, stir evenly, then add fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agent, and continue to stir until uniform to obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

[0016] Optionally, the process parameters of the double-roll granulation include: roller gap 2.5-3.5 mm, roller speed 800-1000 rpm, feed rate 10-12 t / h, and water content of the mixture less than 15%.

[0017] Optionally, the process parameters of the high temperature sintering include: preheating to 500-650° C., maintaining for more than 60 minutes, heating to 1100-1170° C., and maintaining for 15-25 minutes.

[0018] In the present invention, the composition and function of each raw material are analyzed as follows: 1. Fly ash: The main component is SiO 2 、Al 2 O 3 ,CaO,Fe 2 O 3 Oxides such as SiO 2 The highest content, followed by Al 2 O 3 Fly ash contains heavy metals, such as Pb and Cd, and their content is affected by the composition of the garbage and the incineration process. At high temperatures, fly ash can form a glass phase with other raw material components, encapsulating heavy metals such as Pb and Cd in the fly ash and reducing the risk of leaching; at the same time, the addition amount is appropriate to ensure sufficient silicon and aluminum sources. Too low may weaken the strength, and too high may affect the pore structure.

[0019] 2. Solid waste sludge: at least one of domestic sewage sludge, printing and dyeing factory sludge, paper mill sludge and winery sludge can be selected. Each solid waste sludge has different components and properties due to its different sources. The present invention preferably uses domestic sewage sludge: printing and dyeing sludge: paper mill sludge = (35-45): 30:30. Among them, domestic sewage sludge contains more organic matter, which can be decomposed at high temperature to form macropores and reduce density; printing and dyeing sludge contains more cellulose, which can form some micropores after carbonization to improve pore connectivity, and heavy metal Cr³⁺ can be dissolved in the glass phase; paper mill sludge contains calcium sulfate and some cellulose, and high-temperature carbonization of cellulose can improve porosity. The pore structure of the product can be improved by the synergy of the above raw materials, forming a combination of multi-level pores, taking into account the requirements of density and strength, and not easy to collapse and deform.

[0020] 3. Fly ash: contains a lot of SiO 2 and Al 2 O 3, supplement the silicon-aluminum skeleton, enhance the sintering activity, and can synergize with the components in fly ash and other raw materials to form a stable mineral phase, prevent the ceramsite from cracking during the preparation process, and improve the product forming rate.

[0021] 4. Red mud: contains high Al 2 O 3 and Fe 2 O 3 , is alkaline, provides Fe 2 O 3 Flux, reduce sintering temperature, Fe 2 O 3 Na in saline waste + The formation of Na-Fe-Al-Si-O low-temperature eutectic system at high temperature can effectively reduce the sintering temperature, improve the strength and durability of ceramsite, and reduce environmental pollution.

[0022] 5. Salt-containing waste: mainly comes from chemical, metallurgical, food processing, pharmaceutical, salt and other industries. The composition of waste salt is relatively complex, mainly including inorganic salts such as sodium chloride (NaCl) and potassium chloride (KCl). The present invention requires that the Cl⁻ content is less than 2%; Na + , K + With SiO 2 A low eutectic phase can be formed at high temperature, reducing the sintering temperature by about 50°C.

[0023] 6. Bentonite: The main chemical components of bentonite include silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ) and water (H 2 O), in addition to iron, magnesium, calcium, sodium, potassium and other elements, with good plasticity and adhesion, it can replace clay minerals, adjust the plasticity of ceramsite raw materials, and improve the molding rate of ceramsite. Its water absorption and expansion and adhesion help to form a uniform particle structure in the process of ceramsite production, and prevent the ceramsite from cracking during drying and sintering. Bentonite resources are abundant and the cost is relatively low, which can effectively reduce the production cost of ceramsite. SiO in bentonite 2 and Al 2 O 3 The components can form a stable mineral phase with the components in fly ash, thereby strengthening the skeleton effect of fly ash and improving the strength and stability of expanded clay.

[0024] 7. Pyrolysis residue pore-forming agent: preferably at least one of coal tar residue pyrolysis residue, oily sludge pyrolysis residue and paint residue pyrolysis residue, wherein coal tar residue pyrolysis residue is a solid residue produced by pyrolysis of coal tar residue (a by-product produced in the process of coal tar refining), oily sludge pyrolysis residue is a solid residue produced by pyrolysis of oily sludge (a by-product in the process of oil extraction and processing), and paint residue pyrolysis residue is a solid residue produced by pyrolysis of waste paint residue. All of them contain a certain amount of residual carbon, which can be oxidized at high temperature to generate gas to form a microporous structure, and synergistically improve the pore structure with the solid sludge.

[0025] Compared with the prior art, the present invention has the following beneficial effects: Based on the above technical solution, the present invention provides an environmentally friendly ceramsite prepared by utilizing fly ash, solid hazardous waste and sludge, thereby realizing solid waste resource utilization, reducing the production cost of ceramsite and improving the forming rate of ceramsite.

[0026] In the present invention, fly ash is combined with fly ash and red mud to improve the strength of ceramsite products. At the same time, the addition of an appropriate amount of bentonite can reduce the sintering shrinkage rate, improve the mechanical properties, appearance quality and molding rate of the product; solid waste sludge is combined with pyrolysis residue pore-forming agents to form pore structures of different types and sizes at different temperatures, so that the pore distribution of the product is more uniform, thereby reducing the density of the product. At the same time, the ratio of each raw material is strictly controlled to meet the strength requirements; the heavy metal elements that may be contained in fly ash and solid waste sludge can be dissolved in SiO2 at high temperature. 2 、Al 2 O 3 The gaps in the glass network formed by CaO or entering the mineral phase lattice can control the leaching risk and improve the solidification effect of heavy metals; salt-containing wastes are compounded with high-melting-point fly ash and red mud to inhibit salt volatilization and reduce gas pollution.

[0027] In the preparation process of the present invention, fly ash, red mud and salt-containing waste are first fully mixed to inhibit the volatilization of Cl in the high temperature stage, and fly ash, red mud and salt-containing waste form a pre-reaction matrix, which, as a fluxing core, can improve the uniformity of the subsequent sintering liquid phase distribution; then fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agents are added and fully mixed to make the raw materials evenly dispersed, laying the foundation for subsequent granulation and pore-forming, so that the granulation yield is above 95%. The sintering stage is preheating first and then heating. In the preheating stage, the organic matter in the solid waste sludge decomposes and releases gas to form macropores. In the high temperature stage, the low-temperature eutectic system is formed with the glass phase, the melting point is reduced, and the crystal formation is promoted to form a high-strength skeleton. Moreover, the gas generated by the oxidation of the pore-forming agent forms micropores, which cooperate with the macropores to realize a multi-level pore structure. At the same time, heavy metals and pores are wrapped by the glass phase, reducing the leaching toxicity, and realizing lightweight and high-strength product performance. The ceramsite forming rate can reach more than 90%.

[0028] The present invention uses fly ash, fly ash, red mud and solid waste sludge as main raw materials, and adds salt-containing waste, bentonite and pore-forming agent to form a SiO 2 、Al 2 O 3 and Fe 2 O 3 The main active ingredient system, the density of the prepared ceramsite products is 600-800kg / m 3 Between, cylinder pressure strength ≥5.5MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1. The ceramsite product of the present invention reduces the production cost by more than 20% and increases the ceramsite forming rate by more than 10%. DETAILED DESCRIPTION

[0029] In order to better understand the present invention, the content of the present invention is further clearly set forth in conjunction with the embodiments below, but the protection content of the present invention is not limited to the following embodiments. In the following description, a large number of specific details are provided in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0031] Unless otherwise specified, all raw materials are from commercially available products and do not contain other unspecified components except inevitable impurities unless otherwise specified.

[0032] In the following embodiment, an environmentally friendly ceramsite prepared using fly ash, solid hazardous waste sludge, is made of the following raw materials in parts by weight: 28-38 parts of fly ash, 25-35 parts of solid waste sludge, 10-15 parts of fly ash, 5-10 parts of red mud, 3-7 parts of salt-containing waste, 3-10 parts of bentonite, and 5-10 parts of pyrolysis residue pore-forming agent.

[0033] The solid waste sludge is at least one of domestic sewage sludge, printing and dyeing factory sludge, paper mill sludge and winery sludge.

[0034] The moisture content of solid waste sludge is less than 20%.

[0035] The pyrolysis residue-based pore-forming agent is at least one of pyrolysis residues of coal tar residue, pyrolysis residues of oily sludge and pyrolysis residues of paint residue.

[0036] The mass concentration of chloride ions in saline waste is less than 2%.

[0037] The particle sizes of fly ash, fly ash, red mud and bentonite were sieved through 100 mesh respectively.

[0038] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 47-54%, Al 2 O 3 20-25%, Fe 2 O 3 10-15%, CaO+MgO8-12%, Na 2 O+K 2 O2-4%, the balance is inevitable impurities.

[0039] Example 1: An environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge, is made of the following raw materials in parts by weight: 35 parts of fly ash, 30 parts of solid waste sludge, 12 parts of fly ash, 8 parts of red mud, 4 parts of salt-containing waste, 4 parts of bentonite, and 7 parts of pyrolysis residue of oil-containing sludge. The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge, and papermaking sludge, and the mass ratio of the three is 40:30:30. Its effective ingredients and their mass percentages are: SiO 2 52.5%,Al 2 O 3 20.4%,Fe 2 O 3 12.1%, CaO+MgO8.3%, Na 2 O+K 2 O3.1%.

[0040] The method for preparing environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste and sludge comprises the following steps: S1: fly ash, red mud and salt-containing waste are mixed and stirred evenly, and then fly ash, solid waste sludge, bentonite and oil-containing sludge pyrolysis residue are added, and stirring is continued until uniform to obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

[0041] The process parameters of the double-roll granulation include: roller gap 3 mm, roller speed 900 rpm, feed rate 11 t / h, and water content of the mixture 14.3%.

[0042] The process parameters of high temperature sintering include: preheating to 630°C, maintaining for 60 min, heating to 1150°C, and maintaining for 20 min.

[0043] The granulation yield rate of this embodiment is 97.3%, the ceramsite forming rate is 94.4%, and the bulk density of ceramsite is 520kg / m 3, density grade is 600, cylinder pressure strength is 7.5MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0044] Example 2: An environmentally friendly expanded clay prepared using fly ash and solid hazardous waste sludge is made of the following raw materials in parts by weight: 32 parts of fly ash, 28 parts of solid waste sludge, 15 parts of fly ash, 10 parts of red mud, 7 parts of salt-containing waste, 3 parts of bentonite, and 5 parts of pyrolysis residue of oil-containing sludge. The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge, and papermaking sludge, and the mass ratio of the three is 35:30:30.

[0045] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 48.3%,Al 2 O 3 24.8%,Fe 2 O 3 13.5%, CaO+MgO8.0%, Na 2 O+K 2 O2.3%.

[0046] The above-mentioned method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge is different from that in Example 1 in that the process parameters of double-roll granulation include: roller gap 2.5mm, roller speed 800rpm, feed rate 10t / h, and water content of the mixture 14.1%.

[0047] The process parameters of high temperature sintering include: preheating to 580°C, holding for 75 minutes, heating to 1170°C, and holding for 18 minutes.

[0048] The granulation yield rate of this embodiment is 96.5%, the ceramsite forming rate is 93.7%, and the bulk density of ceramsite is 650kg / m 3 , density grade is 700, cylinder pressure strength is 8.2MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0049] Example 3: An environmentally friendly expanded clay prepared using fly ash, solid hazardous waste sludge, is made of the following raw materials in parts by weight: 30 parts of fly ash, 32 parts of solid waste sludge, 12 parts of fly ash, 6 parts of red mud, 3 parts of salt-containing waste, 10 parts of bentonite, and 7 parts of pyrolysis residue of oily sludge. The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge, and papermaking sludge, and the mass ratio of the three is 45:30:30.

[0050] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 50.1%,Al 2 O 3 20.6%,Fe 2 O 3 14.6%, CaO+MgO9.2%, Na 2 O+K 2 O2.0%.

[0051] The above method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge is different from that of Example 1 in that: The process parameters of the double-roll granulation include: roller gap 3.5 mm, roller speed 1000 rpm, feed rate 12 t / h, and water content of the mixture 14.5%.

[0052] The process parameters of high temperature sintering include: preheating to 500°C, maintaining for 80 min, heating to 1160°C, and maintaining for 18 min.

[0053] The granulation yield rate of this embodiment is 96.0%, the ceramsite forming rate is 94.8%, and the bulk density of the ceramsite is 702kg / m 3 , density grade is 800, cylinder pressure strength is 9.5MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0054] Example 4: An environmentally friendly expanded clay prepared using fly ash and solid hazardous waste sludge is made of the following raw materials in parts by weight: 28 parts of fly ash, 35 parts of solid waste sludge, 10 parts of fly ash, 5 parts of red mud, 6 parts of salt-containing waste, 6 parts of bentonite, and 10 parts of pyrolysis residue of oil-containing sludge. The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge, and papermaking sludge, and the mass ratio of the three is 38:30:30.

[0055] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 47.2%,Al 2 O 3 23.1%,Fe 2 O 3 13.2%, CaO+MgO10.3%, Na 2 O+K 2 O2.1%.

[0056] The above-mentioned method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge is different from that in Example 1 in that the process parameters of the double-roll granulation include: roller gap 3mm, roller speed 920rpm, feed rate 11.5t / h, and water content of the mixture 14.7%; The process parameters of high temperature sintering include: preheating to 650°C, maintaining for 60 min, heating to 1100°C, and maintaining for 25 min.

[0057] The granulation yield rate of this embodiment is 97.2%, the ceramsite forming rate is 95.5%, and the bulk density of ceramsite is 675kg / m 3 , density grade is 700, cylinder pressure strength is 8.5MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0058] Example 5: An environmentally friendly expanded clay prepared using fly ash and solid hazardous waste sludge, is made of the following raw materials in parts by weight: 38 parts of fly ash, 25 parts of solid waste sludge, 13 parts of fly ash, 10 parts of red mud, 3 parts of salt-containing waste, 5 parts of bentonite, and 6 parts of pyrolysis residue of oil-containing sludge. The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge, and papermaking sludge, and the mass ratio of the three is 42:30:30.

[0059] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 53.7%,Al 2 O 3 21.1%,Fe 2 O 3 10.0%, CaO+MgO8.5%, Na 2 O+K 2 O2.4%.

[0060] The preparation method of environmentally friendly ceramsite prepared by utilizing fly ash, solid hazardous waste sludge in this embodiment refers to Example 1.

[0061] The granulation yield rate of this embodiment is 96.7%, the ceramsite forming rate is 94.5%, and the bulk density of the ceramsite is 572kg / m 3 , density grade is 600, cylinder pressure strength is 7.2MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0062] Example 6: An environmentally friendly expanded clay prepared using fly ash, solid hazardous waste sludge, comprising the following raw materials in parts by weight: 33 parts of fly ash, 26 parts of solid waste sludge, 12 parts of fly ash, 9 parts of red mud, 5 parts of salt-containing waste, 7 parts of bentonite, and 8 parts of pyrolysis residue pore-forming agent.

[0063] The pyrolysis residue type pore-forming agent is a composition of coal tar residue pyrolysis residue and oily sludge pyrolysis residue, and the mass ratio of the two is 1:2.

[0064] The solid waste sludge is winery sludge.

[0065] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 49.3%,Al 2 O 3 21.6%,Fe 2 O 3 14.0%, CaO+MgO8.1%, Na 2 O+K 2 O2.0%.

[0066] The method for preparing environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste and sludge comprises the following steps: S1: Mix fly ash, red mud and salt-containing waste, stir evenly, then add fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agent, continue stirring until uniform, and obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

[0067] The process parameters of the double-roll granulation include: roller gap 3 mm, roller speed 830 rpm, feed rate 10.5 t / h, and water content of the mixture 13.2%.

[0068] The process parameters of high temperature sintering include: preheating to 600°C, maintaining for 65 min, heating to 1160°C, and maintaining for 20 min.

[0069] The granulation yield rate of this embodiment is 95.6%, the ceramsite forming rate is 93.2%, and the bulk density of ceramsite is 740kg / m 3 , density grade is 800, cylinder pressure strength is 8.9MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0070] Example 7: An environmentally friendly expanded clay prepared using fly ash, solid hazardous waste sludge, comprising the following raw materials in parts by weight: 30 parts of fly ash, 31 parts of solid waste sludge, 11 parts of fly ash, 5 parts of red mud, 6 parts of salt-containing waste, 8 parts of bentonite, and 9 parts of pyrolysis residue pore-forming agent.

[0071] The pyrolysis residue pore-forming agent is a composition of pyrolysis residue of coal tar residue, pyrolysis residue of oily sludge and pyrolysis residue of paint residue, and the mass ratio of the three is 1:2:0.5.

[0072] The solid waste sludge is a combination of domestic sewage sludge and paper mill sludge, with the mass ratio of the two being 2:1.

[0073] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 48.1%, Al 2 O 3 21.7%,Fe 2 O 3 11.2%, CaO+MgO11.8%, Na 2 O+K 2 O2.2%.

[0074] The method for preparing environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste and sludge comprises the following steps: S1: fly ash, red mud and salt-containing waste are mixed and stirred evenly, and then fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agent are added, and stirring is continued until uniform to obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

[0075] The process parameters of the double-roll granulation include: roller gap 3 mm, roller speed 900 rpm, feed rate 11 t / h, and water content of the mixture 14.5%.

[0076] The process parameters of high temperature sintering include: preheating to 630°C, holding for 60 min, heating to 1155°C, and holding for 23 min.

[0077] The granulation yield rate of this embodiment is 97.4%, the ceramsite forming rate is 95.1%, and the bulk density of ceramsite is 775kg / m 3 , density grade is 800, cylinder pressure strength is 9.1MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0078] Example 8: An environmentally friendly expanded clay prepared using fly ash, solid hazardous waste sludge, comprising the following raw materials in parts by weight: 29 parts of fly ash, 33 parts of solid waste sludge, 13 parts of fly ash, 6 parts of red mud, 4 parts of salt-containing waste, 9 parts of bentonite, and 6 parts of pyrolysis residue pore-forming agent.

[0079] The pyrolysis residue type pore former is the pyrolysis residue of coal tar residue.

[0080] Solid waste sludge is a combination of domestic sewage sludge and printing and dyeing factory sludge, and the mass ratio of the two is 3:1.

[0081] An environmentally friendly ceramsite prepared by using fly ash solid hazardous waste sludge, the effective components and their mass percentages are as follows: SiO 2 50.5%,Al 2 O 3 20.3%,Fe 2 O 3 11.5%, CaO+MgO9.5%, Na 2 O+K 2 O3.9%.

[0082] The method for preparing environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste and sludge comprises the following steps: S1: fly ash, red mud and salt-containing waste are mixed and stirred evenly, and then fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agent are added, and stirring is continued until uniform to obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

[0083] The process parameters of the double-roll granulation include: roller gap 3 mm, roller speed 900 rpm, feed rate 11 t / h, and moisture content of the mixture 14.1%.

[0084] The process parameters of high temperature sintering include: preheating to 640°C, holding for 65 min, heating to 1162°C, and holding for 20 min.

[0085] The granulation yield rate of this embodiment is 96.3%, the ceramsite forming rate is 94.2%, and the bulk density of ceramsite is 630kg / m 3 , density grade is 700, cylinder pressure strength is 8.1MPa, sulfide and sulfate content (according to SO 3 The content of organic matter, chloride (calculated as chloride ion content) and radioactivity all meet the requirements of GB / T17431.1.

[0086] Comparative Example 1: An environmentally friendly ceramsite prepared using fly ash, solid hazardous waste sludge, which is different from the embodiment in that: salt-containing waste is omitted, fly ash is supplemented to 16 parts by weight, and the preparation method remains unchanged.

[0087] The molding rate of ceramsite in this comparative example is 87.3%, and the bulk density of ceramsite product is 850 kg / m 3 , the density grade is 900, and the cylinder pressure strength is 7.6MPa. Compared with Example 1, it can be seen that by omitting the salt-containing waste, the molding rate of the ceramsite is reduced, the density is increased, and the cylinder pressure strength is not significantly improved.

[0088] Comparative Example 2: An environmentally friendly expanded clay prepared using fly ash and hazardous waste sludge, which is different from the embodiment in that the weight portion of salt-containing waste is increased to 10 parts, the weight portion of fly ash is reduced to 29 parts, and the preparation method remains unchanged.

[0089] The ceramsite forming rate in this comparative example is 78.4%, the cylinder pressure strength of the ceramsite product is only 3.8MPa, and the bulk density is 535kg / m 3 , the density grade is 600. Compared with Example 1, it can be seen that the excessive use of salt-containing waste is not conducive to the molding of expanded clay, and although the density of expanded clay is reduced, the decrease in cylinder pressure strength is more significant, and the overall performance is not good.

[0090] Comparative Example 3: An environmentally friendly ceramsite prepared using fly ash, solid hazardous waste sludge, which is different from the embodiment in that clay is used instead of bentonite, and the preparation method remains unchanged.

[0091] In this comparative example, the granulation finished product rate is 85.6%, and the ceramsite forming rate is 80.2%. It can be seen that the matching performance of bentonite and the raw material of the present invention is more significant, which is more conducive to granulation and forming.

[0092] Comparative Example 4: Different from Example 1, construction waste soil is used instead of solid waste sludge, and the preparation method remains unchanged.

[0093] In this comparative example, the granulation finished product rate is 71.5%, and the ceramsite forming rate is 80.3%. It can be seen that compared with engineering slag, solid waste sludge has better compatibility with the raw materials of the present invention and is more conducive to granulation and forming.

[0094] Comparative Example 5: Different from Example 1, sawdust is used instead of the pyrolysis residue pore-forming agent, and the preparation method remains unchanged.

[0095] In this comparative example, the ceramsite forming rate is 85.4%, the cylinder pressure strength of the ceramsite product is only 4.3MPa, and the bulk density is 550kg / m 3 , the density level is 600. It can be seen that the effect of the above substitution is not as good as that of Example 1.

[0096] Comparative Example 6: Different from Example 1, the high-temperature sintering temperature in the preparation method is set to 1030°C, and the other conditions remain unchanged.

[0097] The ceramsite forming rate is 79.5%, the Pb leaching of the ceramsite product exceeds the standard, and the cylinder pressure strength is reduced to 5.3MPa. It can be seen that when the sintering temperature is lower than the set temperature of the present invention, the solidification effect of the heavy metal is significantly deteriorated, and the product strength decreases.

[0098] In summary, the ceramsite product of the present invention has outstanding raw material synergistic effect, more significant product performance, is easy to prepare and shape, improves the yield rate, and has more practical value.

[0099] The ceramsite product prepared by the invention can be used as light aggregate for building materials.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An environmentally friendly ceramsite prepared from fly ash, solid hazardous waste and sludge, characterized by: The invention comprises the following raw materials in parts by weight: 28-38 parts of fly ash, 25-35 parts of solid waste sludge, 10-15 parts of fly ash, 5-10 parts of red mud, 3-7 parts of salt-containing waste, 3-10 parts of bentonite and 5-10 parts of pyrolysis residue pore-forming agent.

2. The environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge as claimed in claim 1, characterized in that: The pyrolysis residue pore-forming agent is at least one of pyrolysis residue of coal tar residue, pyrolysis residue of oily sludge and pyrolysis residue of paint residue.

3. The environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge as claimed in claim 1, characterized in that: The solid waste sludge is at least one of domestic sludge, printing and dyeing sludge, papermaking sludge and winery sludge.

4. The environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge as claimed in claim 3, characterized in that: The solid waste sludge is a combination of domestic sludge, printing and dyeing sludge and papermaking sludge, and the mass ratio of the three is (35-45):30:

30.

5. The environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste sludge as claimed in claim 1, characterized in that: The mass concentration of chloride ions in the saline waste is less than 2%.

6. The environmentally friendly ceramsite prepared by using fly ash, solid hazardous waste and sludge as claimed in claim 1, characterized in that: The particle sizes of the fly ash, fly ash, red mud and bentonite are all ≤100 meshes.

7. A method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Mix fly ash, red mud and salt-containing waste, stir evenly, then add fly ash, solid waste sludge, bentonite and pyrolysis residue pore-forming agent, continue stirring until uniform, and obtain a mixture; S2: performing double-roll granulation on the mixed material to obtain granules; S3: sintering the pellets at high temperature and cooling them to obtain ceramsite products.

8. The method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge as claimed in claim 7, characterized in that: The process parameters of the double-roll granulation include: roller gap 2.5-3.5 mm, roller speed 800-1000 rpm, feed rate 10-12 t / h, and water content of the mixture less than 15%.

9. The method for preparing environmentally friendly ceramsite using fly ash, solid hazardous waste sludge as claimed in claim 7, characterized in that: The process parameters of the high temperature sintering include: preheating to 500-650° C., maintaining for more than 60 minutes, heating to 1100-1170° C., and maintaining for 15-25 minutes.