Carbon curing red mud-regenerated micropowder core-shell type ceramsite adsorbent, and preparation method and application thereof

Abstract

The application discloses a kind of carbon maintenance red mud-regenerated micro powder core-shell type ceramsite adsorbent and its preparation method and application.The adsorbent includes the following components by weight: sludge biochar 60-100 parts, red mud 30-60 parts, regenerated micro powder 50-80 parts, water 10-20 parts, pore-forming agent 2-5 parts, activator 0-5 parts, chelating agent 1-3 parts;Its preparation method is as follows: B1: after mixing red mud, regenerated micro powder and pore-forming agent, add sludge biochar and continue to mix evenly;B2: dissolve activator and chelating agent;B3: spray solution granulation, and screening is obtained the ceramsite green ball with particle size of 5-10mm;B4: carbon maintenance red mud-regenerated micro powder core-shell type ceramsite adsorbent is obtained by carrying out carbon maintenance 1 day to ceramsite green ball;B5: after curing, the particle is placed in water, and is cured for 3-28 days.The ceramsite has the characteristics of low carbon, light weight and high adsorption, and effectively utilizes waste, reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of adsorbent preparation technology, specifically to a carbon-cured red mud-regenerated micro powder core-shell type ceramic adsorbent, its preparation method, and its application. Background Technology

[0002] Red mud, recycled micronized powder, and municipal sludge are three types of solid waste generated during urban and industrial development.

[0003] Red mud is a solid waste generated during the alumina production process of bauxite ore. Its main components include alumina, iron oxide, silicon dioxide, and alkaline oxides such as sodium and potassium. Due to its high alkalinity and heavy metal content, red mud can easily cause serious environmental pollution during storage. Its storage not only occupies land but also easily pollutes the environment. With the rapid development of cities and industries worldwide, the production of municipal sludge and red mud will continue to increase, urgently requiring effective resource utilization methods.

[0004] Recycled micron powder is a fine powder material obtained from construction waste through crushing, screening, and other processing techniques. Its main components include cement hydration products, unhydrated cement particles, aggregate particles, and the old mortar they encapsulate. With the acceleration of urbanization, a large amount of construction waste is constantly being generated. Traditional disposal methods mainly involve landfilling or simple dumping, which not only wastes a large amount of renewable resources but also causes environmental pollution and resource waste. Therefore, improving the utilization rate of recycled micron powder has become an important issue for the current construction industry.

[0005] Municipal sewage sludge contains large amounts of organic matter, pathogens, heavy metals, and other components. Direct discharge of these components without proper treatment will cause serious environmental pollution, such as heavy metal contamination of soil and water sources, and damage to ecosystems. Sludge biochar, as an effective sludge disposal method, can transform sludge through a high-temperature pyrolysis process, reducing its volume and stabilizing heavy metals. It has high adsorption capacity and can be used as an adsorbent to remove pollutants from water. However, unmodified sludge biochar may still release heavy metals, posing a potential threat to the environment; therefore, appropriate modification is necessary to enhance its stability and adsorption performance.

[0006] Expanded clay aggregates are widely used as adsorbents in water purification processes, exhibiting adsorption characteristics similar to those of sludge biochar. While the application of red mud and regenerated micro-powder in expanded clay aggregate preparation has been explored, their respective utilization in this field still faces several limitations. Red mud, due to its high alkalinity and heavy metal content, can easily lead to unstable product performance when used in expanded clay aggregates. Furthermore, the complex composition and poor stability of regenerated micro-powder also pose challenges to the preparation of expanded clay aggregates.

[0007] This invention combines red mud, recycled micronized powder, and sludge biochar to synergistically prepare ceramsite adsorbents, offering significant advantages. First, sludge biochar, with its lightweight and high adsorption capacity, serves as a framework, reducing the mass of the ceramsite while simultaneously improving its adsorption performance. Second, the synergistic preparation of the shell material from red mud and recycled micronized powder effectively neutralizes the alkalinity of the red mud, improving the stability and safety of the shell material. Simultaneously, the shell material can solidify heavy metals in the red mud and sludge biochar, reducing environmental pollution. Furthermore, utilizing these solid wastes as raw materials not only reduces dependence on natural resources and lowers production costs but also brings economic benefits.

[0008] Therefore, it is essential to develop a novel, low-carbon, and economical ceramsite adsorbent and its preparation method. Summary of the Invention

[0009] The purpose of this invention is to provide a carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent and its preparation method, so as to achieve the synergistic treatment of red mud, regenerated micro powder and municipal sludge, and at the same time obtain a core-shell type ceramsite adsorbent with good adsorption performance.

[0010] To achieve the above objectives, the present invention employs the following technical means:

[0011] A carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent, the raw materials of which include the following components by weight: 60-100 parts of sludge biochar, 30-60 parts of red mud, 50-80 parts of regenerated micro powder, 10-20 parts of water, 2-5 parts of pore-forming agent, 0-5 parts of activator, and 1-3 parts of chelating agent.

[0012] Furthermore, the sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0013] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0014] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0015] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After constant temperature pyrolysis at 400-600℃ for 0.5-2 hours, stop heating and cool to room temperature to initially form biochar.

[0016] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 6-10 hours to obtain sludge biochar.

[0017] Furthermore, the red mud and regenerated micro powder have an average particle size of 10-20 μm, wherein the activity index of the regenerated micro powder is greater than 0.7.

[0018] Furthermore, the pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm.

[0019] Furthermore, the activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 10-15:1.

[0020] Furthermore, the chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0021] This invention also provides a method for preparing a carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent, comprising the following steps:

[0022] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 2-4 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0023] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0024] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm; the granulator speed is 30-40rpm, and granulation is carried out continuously for 6-12min, during which the additive solution is sprayed evenly. After the granulation is completed, it continues to run for 1-3min to compact the particles.

[0025] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 20%±2%-40%±2%;

[0026] B5: Place the carbon-cured granules in water and cure for 3-28 days to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic adsorbent; the curing conditions are: temperature 25±2℃, humidity above 90%.

[0027] The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent described in this invention can be used to remove Pb from water. 2+ Cu 2+ Or PO4 2- At room temperature, the carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent is added at a mass ratio of 1:20 to water.

[0028] The present invention has the following beneficial effects:

[0029] 1. This invention utilizes red mud, recycled micronized powder, and municipal sludge as main raw materials, significantly reducing cement usage and dependence on natural resources. Red mud, recycled micronized powder, and municipal sludge are all solid wastes. This method not only effectively reduces environmental pollution from industrial waste and construction debris, but also employs a non-fired carbon curing process, which, compared to sintered ceramsite, reduces carbon emissions during the sintering process and absorbs CO2, aligning with the green and low-carbon environmental protection concept.

[0030] 2. During the preparation process, the shell material encapsulates the sludge biochar, reducing the leaching of heavy metals from the sludge biochar. At the same time, sodium hexametaphosphate and sodium polyacrylate are used, which act as chelating agents and water-reducing agents. While optimizing the fluidity, they further ensure the stability of the solidified heavy metals and prevent their migration and release in the environment, thereby improving the safety performance and environmental benefits of the ceramsite adsorbent.

[0031] 3. Due to its rough and porous surface, and the clay minerals contained in red mud, both sludge biochar and red mud exhibit excellent adsorption properties. During the preparation of ceramsite, a pore-forming agent is added to the shell material to maintain the porous characteristics of the ceramsite and compensate for potential pore clogging caused by sludge biochar. This ceramsite prepared using red mud not only possesses excellent adsorption and solidification capabilities but also further enhances the product's market competitiveness. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating the preparation method of a carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] A carbon-conserved red mud-regenerated micro-powder core-shell type ceramsite adsorbent comprises the following components in parts by weight: 70 parts sludge biochar, 35 parts red mud, 60 parts regenerated micro-powder, 18 parts water, 3 parts pore-forming agent, 4 parts activator, and 1 part chelating agent. The average particle size of the red mud and regenerated micro-powder is 10 μm, wherein the activity index of the regenerated micro-powder is 0.85. The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm. The activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 10:1. The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0036] The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0037] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0038] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0039] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After pyrolysis at 600℃ for 1 hour, stop heating and cool to room temperature to initially form biochar.

[0040] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 10 hours to obtain sludge biochar.

[0041] The carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is prepared in the following manner:

[0042] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 3 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0043] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0044] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm. During granulation, the granulator speed is 35rpm, and granulation is carried out continuously for 9min. During this period, the additive solution is sprayed evenly. After the granulation is completed, the granulator continues to run for 3min to compact the particles.

[0045] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 30%±2%;

[0046] B5: Place the cured granules in water and cure for 28 days. The curing conditions are: temperature 25±2℃ and humidity above 90%, to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent.

[0047] Example 2

[0048] A carbon-conserved red mud-regenerated micro-powder core-shell type ceramsite adsorbent comprises the following components in parts by weight: 80 parts sludge biochar, 30 parts red mud, 80 parts regenerated micro-powder, 20 parts water, 5 parts pore-forming agent, 5 parts activator, and 2 parts chelating agent. The average particle size of the red mud and regenerated micro-powder is 12 μm, wherein the activity index of the regenerated micro-powder is 0.8. The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm. The activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 12:1. The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0049] The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0050] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0051] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0052] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After pyrolysis at 500℃ for 2 hours, stop heating and cool to room temperature to initially form biochar.

[0053] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 9 hours to obtain sludge biochar.

[0054] The carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is prepared in the following manner:

[0055] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 2 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0056] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0057] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm. During granulation, the granulator speed is 40rpm, and granulation is carried out continuously for 7min. During this period, the additive solution is sprayed evenly. After the granulation is completed, the granulator continues to run for 1min to compact the particles.

[0058] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 40%±2%;

[0059] B5: Place the cured granules in water and cure for 28 days. The curing conditions are: temperature 25±2℃ and humidity above 90%, to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent.

[0060] Example 3

[0061] A carbon-conserved red mud-regenerated micro-powder core-shell type ceramsite adsorbent comprises the following components in parts by weight: 60 parts sludge biochar, 45 parts red mud, 65 parts regenerated micro-powder, 18 parts water, 4 parts pore-forming agent, 3 parts activator, and 3 parts chelating agent. The average particle size of the red mud and regenerated micro-powder is 16 μm, wherein the activity index of the regenerated micro-powder is 0.78. The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm. The activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 15:1. The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0062] The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0063] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0064] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0065] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After pyrolysis at 500℃ for 1 hour, stop heating and cool to room temperature to initially form biochar.

[0066] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 8 hours to obtain sludge biochar.

[0067] The carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is prepared in the following manner:

[0068] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 3 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0069] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0070] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm. During granulation, the granulator speed is 40rpm, and granulation is carried out continuously for 8min. During this period, the additive solution is sprayed evenly. After the granulation is completed, the granulator continues to run for 2min to compact the particles.

[0071] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 40%±2%;

[0072] B5: Place the cured granules in water and cure for 28 days. The curing conditions are: temperature 25±2℃ and humidity above 90%, to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent.

[0073] Example 4

[0074] A carbon-conserved red mud-regenerated micro-powder core-shell type ceramsite adsorbent comprises the following components in parts by weight: 100 parts sludge biochar, 60 parts red mud, 50 parts regenerated micro-powder, 10 parts water, 2 parts pore-forming agent, 1 part activator, and 3 parts chelating agent. The average particle size of the red mud and regenerated micro-powder is 10 μm, wherein the activity index of the regenerated micro-powder is 0.75. The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm. The activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 13:1. The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0075] The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0076] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0077] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0078] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After pyrolysis at 600℃ for 2 hours, stop heating and cool to room temperature to initially form biochar.

[0079] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 7 hours to obtain sludge biochar.

[0080] The carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is prepared in the following manner:

[0081] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 4 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0082] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0083] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm. During granulation, the granulator speed is 35rpm, and granulation is carried out continuously for 6min. During this period, the additive solution is sprayed evenly. After the granulation is completed, the granulator continues to run for 2min to compact the particles.

[0084] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 30%±2%;

[0085] B5: Place the cured granules in water and cure for 28 days. The curing conditions are: temperature 25±2℃ and humidity above 90%, to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent.

[0086] Example 5

[0087] A carbon-conserved red mud-regenerated micro-powder core-shell type ceramsite adsorbent comprises the following components in parts by weight: 60 parts sludge biochar, 55 parts red mud, 35 parts regenerated micro-powder, 15 parts water, 2 parts pore-forming agent, 0 parts activator, and 2 parts chelating agent. The average particle size of the red mud and regenerated micro-powder is 20 μm, wherein the activity index of the regenerated micro-powder is 0.73. The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm. The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:1.

[0088] The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps:

[0089] Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge.

[0090] Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls.

[0091] Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After pyrolysis at 400℃ for 0.5h, stop heating and cool to room temperature to initially form biochar.

[0092] Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 6 hours to obtain sludge biochar.

[0093] The carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is prepared in the following manner:

[0094] B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 3 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture.

[0095] B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions;

[0096] B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm. During granulation, the granulator speed is 30rpm, and granulation is carried out continuously for 12min. During this period, the additive solution is sprayed evenly. After the granulation is completed, the granulator continues to run for 1min to compact the particles.

[0097] B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 20%±2%;

[0098] B5: Place the cured granules in water and cure for 28 days. The curing conditions are: temperature 25±2℃ and humidity above 90%, to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic granule adsorbent.

[0099] Example 6

[0100] The difference between Example 1 and Example 2 is the preparation method of the carbon-cured red mud-regenerated micronized core-shell ceramsite adsorbent: step B5 is curing for 3 days. Everything else is the same as in Example 1.

[0101] Example 7

[0102] The difference between Example 1 and Example 2 is the preparation method of the carbon-cured red mud-regenerated micronized core-shell ceramsite adsorbent: step B5 is curing for 7 days. Everything else is the same as in Example 1.

[0103] Example 8

[0104] The difference between Example 1 and Example 2 is the preparation method of the carbon-cured red mud-regenerated micronized core-shell ceramsite adsorbent: step B5 is curing for 14 days. Everything else is the same as in Example 1.

[0105] After preparation, all samples were tested in accordance with GB / T 17431.2-2010 "Lightweight aggregates and their test methods - Part 2: Lightweight aggregates test methods", and the results are shown in Table 1.

[0106] Table 1. Test results of physical and mechanical properties of Examples 1-8

[0107]

[0108]

[0109] The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbents prepared in Examples 1-8 exhibit good physical and mechanical properties. With increasing red mud mass content, the compressive strength of the ceramsite decreases, while the bulk density and 1-hour water absorption rate increase. This indicates that the increase in red mud makes the ceramsite more compact, thus affecting its mechanical and water resistance properties. Sodium hexametaphosphate and sodium polyacrylate, as chelating agents, have different effects on the properties of the ceramsite. Sodium hexametaphosphate can more effectively stabilize heavy metals and improve the water resistance of the ceramsite, while sodium polyacrylate helps to further improve the compressive strength of the ceramsite.

[0110] In addition, adsorption performance tests were conducted on carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent. Wastewater was simulated using 50 mg / L Pb(NO3)2 solution, 50 mg / L CuCl2 solution, and 50 mg / L KH2PO4 solution, respectively, at a mass ratio of ceramsite adsorbent:simulated solution = 1:20. The ceramsite adsorbent was added, and adsorption was carried out at room temperature with shaking for 24 h. The pollutant removal rate was then measured, and the results are shown in Table 2.

[0111] Table 2 shows the removal rates of each ion in Examples 1-8.

[0112] Case <![CDATA[Pb 2+ (%)]]> <![CDATA[Cu 2+ (%)]]> <![CDATA[PO4 2- (%)]]> Example 1 82.33 80.51 93.22 Example 2 81.32 78.93 90.01 Example 3 79.10 78.82 91.76 Example 4 79.21 71.31 87.36 Example 5 76.84 76.34 85.68 Example 6 78.25 77.32 89.4 Example 7 80.24 78.11 90.73 Example 8 81.63 80..20 92.51

[0113] As can be seen from the data in Table 2, the carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbents prepared in Examples 1-8 have a good effect on Pb. 2+ Cu 2+ and PO4 2- The adsorption performance of all components was significantly improved.

[0114] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent, characterized in that, Its raw materials include the following components by weight: 60-100 parts sludge biochar, 30-60 parts red mud, 50-80 parts regenerated micro powder, 10-20 parts water, 2-5 parts pore-forming agent, 0-5 parts activator, and 1-3 parts chelating agent; its preparation method includes the following steps: B1: Place red mud, regenerated micro powder and pore-forming agent in a granulator and mix for 2-4 minutes. Then add sludge biochar and run the granulator for 2 minutes to mix thoroughly to obtain a mixture. B2: Divide the water into two portions, and dissolve the activator and chelating agent in different portions of water to obtain two additive solutions; B3: Two additive solutions are continuously sprayed for granulation to obtain spherical particles, which are then sieved to obtain ceramsite raw material balls with a particle size of 5-10mm; the granulator speed is 30-40rpm, and granulation is carried out continuously for 6-12min, during which the additive solution is sprayed evenly. After the granulation is completed, it continues to run for 1-3min to compact the particles. B4: Carbon-cur the raw material pellets for 1 day; the carbon curing conditions are: temperature 25±2℃, humidity 50%±2%, CO2 concentration 20%±2%-40%±2%; B5: Place the carbon-cured granules in water and cure for 3-28 days to obtain carbon-cured red mud-regenerated micro powder core-shell type ceramic adsorbent; the curing conditions are: temperature 25±2℃, humidity above 90%.

2. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to claim 1, characterized in that, The sludge biochar is prepared from municipal sludge, and its preparation method includes the following steps: Step A1: Place the filter press sludge cake, which has had a large amount of water removed by the filter press, into a drying oven and dry it at 105℃ for 24 hours. After preliminary crushing by a crusher, pass it through a 150-mesh sieve to obtain dry sludge. Step A2: Put the dry sludge into a granulator, add an appropriate amount of water, prepare sludge balls with a diameter of 1cm, and then put them into a drying oven at 50℃ for 5h to obtain sludge balls. Step A3: Place the sludge balls in a high-temperature tubular furnace, and under a nitrogen atmosphere, control the heating rate at 5℃ / min. After constant temperature pyrolysis at 400-600℃ for 0.5-2 hours, stop heating and cool to room temperature to initially form biochar. Step A4: Wash the biochar repeatedly with deionized water to remove soluble impurities, and then dry it at 105℃ for 6-10 hours to obtain sludge biochar.

3. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to claim 1, characterized in that, The red mud and regenerated micro powder have an average particle size of 10-20 μm, and the activity index of the regenerated micro powder is greater than 0.

7.

4. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to claim 1, characterized in that, The pore-forming agent is aluminum powder with a particle size of 0.5-2.0 μm.

5. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to claim 1, characterized in that, The activator is prepared by mixing water glass and sodium hydroxide in a mass ratio of 10-15:

1.

6. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to claim 1, characterized in that, The chelating agent is prepared by mixing sodium hexametaphosphate and sodium polyacrylate in a mass ratio of 1:

1.

7. The carbon-cured red mud-regenerated micro-powder core-shell type ceramsite adsorbent according to any one of claims 1-6 for the removal of Pb from water. 2+ Cu 2+ Or PO4 2- Applications in [the field].

8. The application according to claim 7, characterized in that: At room temperature, the carbon-cured red mud-regenerated micro powder core-shell type ceramsite adsorbent is added at a mass ratio of 1:20 to water.

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