Method for harmlessly treating red mud by utilizing vegetable oil residues and application of method in asphalt

Abstract

The invention discloses a method for harmlessly treating red mud by utilizing vegetable oil residues and application of the method in asphalt, and belongs to the field of green resource recycling of solid wastes. The method for harmlessly treating the red mud by using the vegetable oil residues comprises the following steps: mixing the red mud with an acid leaching solution, and carrying out acid leaching treatment to obtain a red mud acid leaching solution; ferrous sulfate is added into the red mud pickle liquor, reduction treatment is carried out, and red mud treatment liquor is obtained; vegetable oil residues are added into the red mud treatment liquid, complexation reaction and solid-liquid separation are carried out, and the vegetable oil residue modified red mud is obtained. The method does not need complex high-temperature and high-pressure conditions, and is simple to operate, environment-friendly and low in cost. Experiments prove that after the plant oil residue modified red mud is added into the asphalt, the ageing resistance, the ductility, the rutting resistance and the like of the asphalt can be improved, so that the service life of an asphalt pavement is prolonged, and the asphalt pavement is more environment-friendly.

Description

Technical Field

[0001] The present invention relates to the field of green resource recycling of solid waste, and particularly to a method for harmless treatment of red mud using vegetable oil residue and its application in asphalt. Background Art

[0002] Red mud is an industrial waste generated during the extraction of bauxite. Since bauxite contains relatively more metal elements such as iron, calcium, sodium, and aluminum, it is likely to result in complex composition of red mud and contain a large amount of harmful substances. Due to its strong alkalinity, it is easy to cause pollution to water sources, soil, and air. Therefore, how to safely and effectively treat red mud has become a key issue.

[0003] Existing red mud treatment technologies mostly focus on disposal through physical, chemical, or biological methods. However, these methods generally have problems such as high treatment costs, low efficiency, and possible secondary pollution during the treatment process, and there are certain limitations. For example, traditional chemical treatment methods often require a large amount of chemical reagents and may cause secondary pollution; physical treatment methods such as landfill and stacking can solve short-term problems, but cannot fundamentally reduce the environmental harm of red mud. Although the biological method for treating red mud shows good degradation effects in some cases, its technology is still in the research stage and faces problems such as low efficiency and long treatment cycles. Therefore, it is crucial to explore a new technology that can efficiently and environmentally treat red mud and realize resource utilization. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for harmless treatment of red mud using vegetable oil residue and its application in asphalt to solve the above problems in the background art. This method does not require complex high-temperature and high-pressure conditions, is simple to operate, environmentally friendly, and has low costs. It has been experimentally proven that after adding this vegetable oil residue-modified red mud into asphalt, the anti-aging property, ductility, and rutting resistance of the asphalt can be improved, thereby extending the service life of the asphalt pavement and making it more environmentally friendly.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention: Provide a method for harmless treatment of red mud using vegetable oil residue. After acid leaching treatment of the red mud, vegetable oil residue is added for complexation reaction to obtain vegetable oil residue-modified red mud.

[0007] Acid leaching treatment can dissolve soluble alkaline substances and heavy metal oxides in red mud into soluble ionic compounds. During this process, inorganic and organic acids that can undergo neutralization reactions with metal oxides are mainly used.

[0008] Vegetable oil residue is generally a waste generated by plant oil extraction in factories.

[0009] Preferably, the acid leaching solution contains sulfuric acid and nitric acid.

[0010] Preferably, the method comprises the following steps:

[0011] Mix the red mud with the acid leaching solution and perform acid leaching treatment to obtain a red mud acid leaching solution;

[0012] Add ferrous sulfate to the red mud acid leaching solution and perform reduction treatment to obtain a red mud treatment solution;

[0013] Add vegetable oil residue to the red mud treatment solution, perform complexation reaction, and carry out solid-liquid separation to obtain the vegetable oil residue modified red mud.

[0014] Preferably, the particle size of the red mud is 200 - 300 mesh; and / or, the pH value of the acid leaching solution is 3 - 4; and / or, the liquid-solid ratio of the acid leaching solution to the red mud is 3 - 10 mL:1 g.

[0015] Preferably, the time of the acid leaching treatment is 12 - 24 h; and / or, the acid leaching treatment is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

[0016] Preferably, the mass ratio of ferrous sulfate to red mud is 0 - 0.05:1 and not 0; and / or, the time of the reduction treatment is 1 - 3 h; and / or, the reduction treatment is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

[0017] Preferably, the particle size of the vegetable oil residue is 200 - 300 mesh; and / or, the mass ratio of the vegetable oil residue to the red mud is 0.5 - 2:1.

[0018] Preferably, the time of the complexation reaction is 1 - 3 h; and / or, the complexation reaction is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

[0019] The second technical solution of the present invention: Provide a vegetable oil residue modified red mud prepared according to the above method.

[0020] The third technical solution of the present invention: Provide an application of the above vegetable oil residue modified red mud in asphalt modification.

[0021] The fourth technical solution of the present invention: Provide a modified asphalt, which is modified by adding the above vegetable oil residue modified red mud; the addition amount of the vegetable oil residue modified red mud is 1 - 10% of the total mass of the modified asphalt.

[0022] Fifth technical solution of the present invention: Provide a preparation method of the above modified asphalt, including the following steps: Mix the vegetable oil residue modified red mud and asphalt, and stir evenly at a temperature of 150 - 200 °C and a rotation speed of 350 - 450 rpm to make the red mud evenly dispersed in the asphalt.

[0023] The reaction principle of the present invention is as follows:

[0024] In the present invention, by adding vegetable oil residue to carry out a coordination reaction with harmful metal ions in red mud, the content of harmful metal ions in red mud is reduced as much as possible, and the modification effect is improved. Taking metallothionein in vegetable oil residue as an example, it can undergo a complexation reaction with metal ions (such as lead, cadmium, mercury, aluminum, etc.) through sulfhydryl groups (-SH) to form metal-sulfur complexes. These complexes exhibit strong stability, enabling heavy metal ions to be effectively fixed in red mud, preventing their further dissolution or loss, thereby reducing the harm of red mud to the environment and improving the safety and stability of red mud.

[0025] Metallothionein in vegetable oil residue is a class of low molecular weight proteins with abundant sulfhydryl functional groups. Its unique chemical structure enables it to effectively form stable metal-sulfur complexes with various heavy metal ions (such as lead, cadmium, mercury, copper, aluminum, etc.). The sulfhydryl group has strong affinity and can form relatively firm complexes with metal ions through coordination, thereby effectively binding these heavy metal ions in the molecular structure of metallothionein. In this way, metallothionein can effectively reduce the loss and dissolution of harmful heavy metals in red mud, avoiding secondary pollution to the environment.

[0026] Compared with directly carrying out a complexation reaction treatment on acid-leached red mud, in the present invention, by adding ferrous sulfate for reduction treatment, the high-valent metal ions (such as Cr 6+ , As 5+ , etc.) in the reaction system can be reduced to low-valent states, thus facilitating the subsequent removal of metal ions.

[0027] The red mud treated by the present invention can not only be rendered harmless, but also be used as a resource material in asphalt to make modified asphalt. The modification effects it can achieve are as follows:

[0028] Improve the anti-aging performance of asphalt: After testing, it is found that the treated red mud can effectively slow down the aging process of asphalt under high temperature or ultraviolet light, and extend the service life of asphalt; the improvement of this technical effect may be related to the light oil component contained in vegetable oil residue.

[0029] Improve the rutting resistance of asphalt: The mineral components of red mud have a significant promoting effect on the thermal stability and compressive strength of asphalt, can enhance the stability of asphalt at high temperature, and avoid the occurrence of rutting.

[0030] Improve the ductility and crack resistance of asphalt: The addition of red mud helps to improve the ductility of asphalt and enhance the crack resistance of the road surface.

[0031] The modified red mud with vegetable oil residue prepared by the present invention also contains solid vegetable oil residue. After it is applied to asphalt modification, the inventor has found through research that it will not have a negative impact on the asphalt modification effect due to the presence of vegetable oil residue.

[0032] The beneficial technical effects of the present invention are as follows:

[0033] 1. Environmentally friendly and harmless treatment: Traditional methods for treating red mud often involve high costs, complex processes or may cause secondary pollution. However, in the present invention, metallothionein in vegetable oil residue complexes with heavy metal ions in red mud, which can not only efficiently remove heavy metals but also avoid generating new environmental problems, having good green environmental protection characteristics.

[0034] 2. Resource utilization: The present invention realizes the resource utilization of red mud. Applying the treated red mud to asphalt not only solves the problem of red mud disposal but also improves the anti-aging, rutting resistance and crack resistance of asphalt, showing good engineering application value.

[0035] 3. Low cost and high efficiency: Vegetable oil residue is rich in source and inexpensive. Compared with other expensive heavy metal removers, the treatment cost is reduced. At the same time, metallothionein has strong heavy metal adsorption ability and can achieve efficient removal in a short time.

[0036] 4. Simple operation: This method is simple to operate. The harmless treatment of red mud can be achieved through simple dissolution, reaction and separation steps, and the properties of the treated red mud are stable, which is convenient for subsequent resource utilization. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a comparison chart of the change of the complex modulus G*(10Hz) of the red mud modified asphalt in Application Examples 4 - 6 of the present invention with temperature; among them, (a), (b), and (c) are the comparisons of the products in Application Examples 4, 5, and 6 with the control group and SK-70A asphalt respectively, and (d) is the comparison of 5% CZRM-JZ, 5% DDRM-JZ, and 5% HSRM-JZ;

[0039] Figure 2 It is a comparison chart of the change of strain (64°C, 0.1 kPa) of the red mud modified asphalt in Application Examples 4 - 6 of the present invention over time; among them, (a), (b), and (c) are the comparisons of the products in Application Examples 4, 5, and 6 with the control group and SK - 70A asphalt respectively, and (d) is the comparison of 2% CZRM - JZ, 8% DDRM - JZ, and 5% HSRM - JZ;

[0040] Figure 3 It is the FT - IR and the difference of aging index before and after PAV aging of the products in Application Examples 4 - 6 and the control group of the present invention and JZ; among them, (a) is the FT - IR chart, and (b), (c), and (d) are respectively I C＝O (carbonyl group, 1699 cm -1 )、I Ar (aromatic compounds, 1600 cm -1 ) and I Al (aliphatic compounds, 1458 cm -1 ) of the difference of aging index;

[0041] Figure 4 It is a comparison chart of the ion leaching concentration of each sample in Effect Verification 2;

[0042] Figure 5 It is the ultraviolet - visible absorption spectrogram of CZ, DD, and HS. Detailed implementation manners

[0043] Metallothionein is a type of protein containing metal ions, which is distributed in many organisms, especially plants and microorganisms. Metallothionein not only plays a role in regulating metal ion balance in organisms, but also has a certain metal ion detoxification effect, and can bind to harmful metal ions, thereby reducing their toxicity to organisms. Vegetable oil residue is a by - product generated during the processing of edible oil, and its main components include fatty acids, plant proteins, and other organic substances. In recent years, it has been found that vegetable oil residue contains a certain amount of metallothionein, which has certain biological activities and metal ion adsorption abilities. Due to the rich resources and low price of vegetable oil residue, the application of its own metallothionein in the environmental protection field has become a research - promising improvement direction.

[0044] And using vegetable oil residue to harmlessly treat red mud can not only utilize the resource advantages of vegetable oil residue, but also effectively combine the metal ion adsorption characteristics of metallothionein, providing a new idea for the environmental protection treatment of red mud.

[0045] Asphalt is widely used in road construction, building engineering and other fields, and its performance and quality directly affect the durability and safety of the project. With the improvement of environmental protection requirements, it is urgent to replace or modify some components in traditional asphalt. In this context, designing new modification methods for red mud and applying it to asphalt can not only improve the performance of asphalt, but also realize the efficient utilization of red mud, thus forming a green development model of closed-loop utilization in the asphalt industry.

[0046] By allowing heavy metal ions in the acid-leached solution of red mud to undergo a complexation reaction with vegetable oil residue, the adsorption and complexation characteristics of effective components such as metallothionein in it can be utilized to effectively remove harmful metal ions such as lead, cadmium, and arsenic in red mud, thereby realizing the harmless treatment of red mud. This method does not require complex high-temperature and high-pressure conditions, is simple to operate, environmentally friendly and low in cost. In terms of its application in asphalt, by using the treated red mud to modify asphalt, the performance of asphalt can be improved. Through experimental verification, adding vegetable oil residue-modified red mud can improve the anti-aging property, ductility and rutting resistance of asphalt, etc., thus extending the service life of asphalt pavement and making it more environmentally friendly. The method of the present invention has good economic and environmental benefits, and is particularly suitable for the large-scale treatment and resource utilization of red mud, providing a new idea for the comprehensive utilization of red mud.

[0047] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0048] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. It should be noted that the aspects not detailedly described in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0050] Regarding the use of "comprising", "including", "having", "containing", etc. in the present invention, they are all open-ended terms, that is, they are meant to include but not be limited to.

[0051] The preparation method of the acid leaching solution used in the following examples and comparative examples of the present invention is as follows: Concentrated sulfuric acid and concentrated nitric acid with a mass ratio of 2:1 (the molar concentration of concentrated sulfuric acid is 18.4 mol / L, and the molar concentration of concentrated nitric acid is 8 mol / L) are added to deionized water to obtain an acid leaching solution with a pH value of 3.2.

[0052] The source of the red mud used in the following examples and comparative examples of the present invention is Guangxi Pingguo Aluminum Industry, and the main components are shown in Table 1. The sources of rapeseed oil residue powder (CZ), soybean oil residue powder (DD), and peanut oil residue powder (HS) are market oil production workshops.

[0053] Table 1

[0054]

[0055] In the present invention, "room temperature" is calculated as 10 - 30 °C unless otherwise specified.

[0056] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0057] Example 1

[0058] A method for harmless treatment of red mud with vegetable oil residue is as follows:

[0059] (1) Weigh 5 g of red mud (RM) sieved to 200 mesh and place it in 50 mL of leaching solution. At room temperature, invert and oscillate it at a speed of 30 r / min for 20 h with a reverse oscillator to obtain a red mud acid leaching solution;

[0060] (2) Adjust the pH of the red mud acid leaching solution in step (1) to acidic (pH is 2 - 3) with dilute sulfuric acid (H2SO4), add 0.09 g of ferrous sulfate heptahydrate, and continue to invert and oscillate at a speed of 30 r / min for 1 h to obtain a red mud treatment solution;

[0061] (3) Adjust the solution in step (2) to neutral with NaOH solution;

[0062] (4) Add 200 - mesh dried rapeseed oil residue powder (CZ) with different mass ratios (mass ratios to red mud are 1:2, 2:2, 3:2) to the solution in step (3). At a speed of 30 r / min, after inverting and oscillating for 3 h, filter the product after the reaction, wash it repeatedly 3 times with anhydrous ethanol and water, dry it in an oven at 60 °C for 12 h, and then re - grind it to 200 mesh to obtain vegetable oil residue - modified red mud, denoted as rapeseed oil residue - treated red mud (CZRM).

[0063] The step of adjusting the pH to acidic in step (2) and the step of adding NaOH solution in step (3) both facilitate the removal of heavy metal ions. The step of adjusting the pH to acidic in step (2) is because the reaction of metal ions such as divalent iron and hexavalent chromium requires an acidic environment. The step of adding NaOH solution in step (3) is because the solubility of Cr(OH)3 and the like is extremely low in neutral and alkaline environments.

[0064] Example 2

[0065] A method for harmless treatment of red mud with vegetable oil residue is as follows:

[0066] (1) Weigh 5 g of red mud sieved to 200 mesh and place it in 50 mL of leaching solution. Invert and oscillate it at a speed of 30 r / min with an inversion oscillator at room temperature for 20 h to obtain red mud acid leaching solution.

[0067] (2) Adjust the pH of the red mud acid leaching solution in step (1) to acidic (pH = 2 - 3) with dilute sulfuric acid (H2SO4), add 0.09 g of ferrous sulfate heptahydrate, and continue to invert and oscillate at a speed of 30 r / min for 1 h to obtain red mud treatment solution.

[0068] (3) Adjust the solution in step (2) to neutral with NaOH solution.

[0069] (4) Add 200 - mesh dried soybean oil residue powder (DD) with different mass ratios (mass ratios to red mud are 1:2, 2:2, 3:2) to the solution in step (3). At a speed of 30 r / min, after inverting and oscillating for 3 h, filter the product after the reaction, wash it repeatedly 3 times with absolute ethanol and water, dry it in an oven at 60 °C for 12 h, and then re - grind it to 200 mesh to obtain vegetable oil residue - modified red mud, denoted as soybean oil residue - treated red mud (DDRM).

[0070] Example 3

[0071] A method for harmless treatment of red mud with vegetable oil residue is as follows:

[0072] (1) Weigh 5 g of red mud sieved to 200 mesh and place it in 50 mL of leaching solution. Invert and oscillate it at a speed of 30 r / min with an inversion oscillator at room temperature for 20 h to obtain red mud acid leaching solution.

[0073] (2) Adjust the pH of the red mud acid leaching solution in step (1) to acidic (pH = 2 - 3) with dilute sulfuric acid (H2SO4), add 0.09 g of ferrous sulfate heptahydrate, and continue to invert and oscillate at a speed of 30 r / min for 1 h to obtain red mud treatment solution.

[0074] (3) Adjust the red mud treatment liquid in step (2) to neutral with NaOH solution;

[0075] (4) Add 200-mesh dried peanut oil residue powder (HS) with different mass ratios (mass ratios to red mud are 1:2, 2:2, and 3:2 respectively) to the solution in step (3). At a rotation speed of 30 r / min, reverse oscillate for 3 h. After the reaction is completed, filter the product, wash it repeatedly 3 times with anhydrous ethanol and water, dry it in an oven at 60 °C for 12 h, and then re-grind it to 200 mesh to obtain vegetable oil residue-modified red mud, denoted as peanut oil residue-treated red mud (HSRM).

[0076] Application Example 4

[0077] Weigh 200 g of SK-70A asphalt and dry it in an oven at 135 °C for 2 h to remove excess moisture. Add the CZRM of Example 1 to the asphalt, keep it at a constant temperature of 170 °C, and disperse it with a high-speed shearer at 450 rpm for 2 h to obtain modified asphalt CZRM-JZ (the incorporation amounts of CZRM are 2%, 5%, and 8% of the total mass of the modified asphalt respectively, and the obtained products are denoted as 2% CZRM-JZ, 5% CZRM-JZ, and 8% CZRM-JZ respectively).

[0078] Application Example 5

[0079] Weigh 200 g of SK-70A asphalt and dry it in an oven at 135 °C for 2 h to remove excess moisture. Add the DDRM of Example 2 to the asphalt, keep it at a constant temperature of 170 °C, and disperse it with a high-speed shearer at 450 rpm for 2 h to obtain modified asphalt DDRM-JZ (the incorporation amounts of DDRM are 2%, 5%, and 8% of the total mass of the modified asphalt respectively, and the obtained products are denoted as 2% DDRM-JZ, 5% DDRM-JZ, and 8% DDRM-JZ respectively).

[0080] Application Example 6

[0081] Weigh 200 g of SK-70A asphalt and dry it in an oven at 135 °C for 2 h to remove excess moisture. Add the HSRM of Example 3 to the asphalt, keep it at a constant temperature of 170 °C, and disperse it with a high-speed shearer at 450 rpm for 2 h to obtain modified asphalt HSRM-JZ (the incorporation amounts of HSRM are 2%, 5%, and 8% of the total mass of the modified asphalt respectively, and the obtained products are denoted as 2% HSRM-JZ, 5% HSRM-JZ, and 8% HSRM-JZ respectively).

[0082] Control Group

[0083] The difference from Application Example 4 is only that CZRM in the process of preparing the modified asphalt CZRM-JZ is replaced with red mud (the incorporation amount is 2% of the total mass of the modified asphalt), and the obtained product is denoted as RM-JZ.

[0084] Effect Verification 1

[0085] DSR tests were conducted on the products of Application Examples 4 - 6 and the control group, as well as the unmodified SK-70A asphalt (denoted as JZ). The specific test method is as follows: Pour 1.0 g of the modified asphalt in the center of a test plate with a diameter of 25 mm. Move the test plate to extrude the asphalt between the two test plates. Heat the specimen trimmer to trim the excess asphalt around the periphery. Then adjust the gap to a test gap of 1 mm. When the temperature is balanced, the equipment will automatically conduct the test at a frequency of 10 rad / s and the selected stress target value. The recording and calculation are both completed by the data acquisition system. The test results are as Figures 1-3 shown.

[0086] Figure 1 This is a comparison chart of the change of the complex modulus G*(10 Hz) of the red mud modified asphalt of Application Examples 4 - 6 of the present invention with temperature. Among them, (a), (b), and (c) are the comparisons of the products of Application Examples 4, 5, and 6 with the control group and SK-70A asphalt respectively, and (d) is the comparison of 5% CZRM-JZ, 5% DDRM-JZ, and 5% HSRM-JZ.

[0087] From Figure 1 it can be seen that when the complex modulus G* of the three modified asphalts is at 46°C, the complex modulus G* of the CZRM, DDRM, or HSRM modified asphalt in Application Examples 4 - 6 is greater than that of the base asphalt (SK-70A asphalt), which proves that the red mud treated and modified by vegetable oil residue will increase the high-temperature rheological properties of the asphalt after being added to the asphalt.

[0088] Figure 2 This is a comparison chart of the change of the strain (64°C, 0.1 kPa) of the red mud modified asphalt of Application Examples 4 - 6 of the present invention with time. Among them, (a), (b), and (c) are the comparisons of the products of Application Examples 4, 5, and 6 with the control group and SK-70A asphalt respectively, and (d) is the comparison of 2% CZRM-JZ, 8% DDRM-JZ, and 5% HSRM-JZ.

[0089] From Figure 2 it can be seen that after ten multiple creep and recovery cycles, the amplitude of irreversible damage of the three modified asphalts is lower than that of the base asphalt, indicating that the CZRM, DDRM, or HSRM modified asphalt has excellent resistance to permanent deformation and rutting.

[0090] Figure 3Product of Application Example 4 - 6 of the present invention, the control group, and the difference in FT - IR and aging index before and after PAV aging of JZ. Among them, (a) is the FT - IR graph, and (b), (c), (d) are respectively I C＝O (carbonyl, 1699 cm -1 ), I Ar (aromatic compounds, 1600 cm -1 ), and I Al (aliphatic compounds, 1458 cm -1 ) aging index difference.

[0091] As can be seen from Figure 3 , the interpolation change values of functional groups of the three modified asphalts before and after PAV aging are all at a relatively low level, indicating that the anti - aging performance of CZRM, DDRM, or HSRM modified asphalt has been significantly enhanced.

[0092] Effect Verification 2

[0093] To explore the effect of the addition amount of vegetable oil residue powder on the ion concentration in red mud, the following samples were tested. By adjusting the addition amounts of rapeseed oil residue powder (CZ), soybean oil residue powder (DD), and peanut oil residue powder (HS) in Examples 1, 2, and 3 to 2.5 g, 5.0 g, and 7.5 g respectively, a total of nine different samples were prepared (denoted as CZ:RM = 1:2, CZ:RM = 2:2, CZ:RM = 3:2; DD:RM = 1:2, DD:RM = 2:2, DD:RM = 3:2; HS:RM = 1:2, HS:RM = 2:2, HS:RM = 3:2). The Ba, Bi, Co, Cr, Pb, Sb, Sn, Sr, Ti, Tl, and Zn ion concentrations of the above nine samples, unmodified red mud (RM), and the red mud treatment liquid (cRM) in Example 1 were tested. The results are as Figure 4 shown.

[0094] Figure 4 Comparison chart of ion leaching concentrations of each sample for Effect Verification 2.

[0095] As can be seen from Figure 4 , as the addition amount of vegetable oil residue powder increases, the heavy metal ion concentration gradually decreases, and the removal rate is the best when the addition amount is 5.0 g. However, when the amount of vegetable oil residue powder is further increased, the concentration of some heavy metal ions increases slightly. This may be because, at 5.0 g, the metallothionein in the vegetable oil residue has completely complexed the metallothionein in the red mud solution, and 5.0 g is the optimal addition point; when the content of vegetable oil residue is further increased, since the vegetable oil residue also contains trace amounts of heavy metal elements, it will cause a slight increase in the concentration of some heavy metal ions.

[0096] Effect Verification 3

[0097] The ultraviolet-visible absorption spectra of rapeseed residue powder (CZ), soybean residue powder (DD), and peanut residue powder (HS) used in the present invention were plotted. The test results are as Figure 5 shown.

[0098] Figure 5 The ultraviolet-visible absorption spectra of CZ, DD, and HS.

[0099] Figure 5 As shown in [figure], the absorption peaks of DD and HS are mainly concentrated between 260 nm and 285 nm, mainly due to aromatic amino acids (such as tryptophan, tyrosine, and phenylalanine) in proteins; the absorption peak of DD is located near 260 nm, indicating a relatively high content of amino acids such as phenylalanine in its protein; while the absorption peak of HS is located near 285 nm, indicating a relatively rich content of amino acids such as tryptophan and tyrosine in its protein. The absorption peak of the protein in CZ has shifted, possibly because small molecule substances (such as polysaccharides, lipids, and minerals, etc.) in it interact with the protein, affecting the electron cloud distribution of aromatic amino acids in the protein, resulting in a red shift phenomenon in the ultraviolet absorption spectrum. Although the ultraviolet absorption peak of cysteine usually appears near 260 nm and the absorption intensity is weak, all three samples have absorption peaks at 260 nm, which indicates the presence of metallothionein in CZ, DD, and HS.

[0100] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for harmless treatment of red mud using vegetable oil residue, characterized in that, After acid leaching the red mud, vegetable oil residue is added for complexation reaction to obtain vegetable oil residue modified red mud.

2. The method according to claim 1, characterized in that, It includes the following steps: Mix the red mud with the acid leaching solution and perform acid leaching treatment to obtain red mud acid leaching solution; Add ferrous sulfate to the red mud acid leaching solution and perform reduction treatment to obtain red mud treatment solution; Add vegetable oil residue to the red mud treatment solution, perform complexation reaction, and carry out solid-liquid separation to obtain the vegetable oil residue modified red mud.

3. The method according to claim 2, wherein The particle size of the red mud is 200 - 300 mesh; and / or, the pH value of the acid leaching solution is 3 - 4; and / or, the liquid-solid ratio of the acid leaching solution to the red mud is 3 - 10 mL:1 g.

4. The method according to claim 1 or 2, characterized in that, The time of the acid leaching treatment is 12 - 24 h; and / or, the acid leaching treatment is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

5. The method according to claim 2, wherein The mass ratio of ferrous sulfate to the red mud is 0 - 0.05:1 and not 0; and / or, the time of the reduction treatment is 1 - 3 h; and / or, the reduction treatment is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

6. The method according to claim 2, wherein The particle size of the vegetable oil residue is 200 - 300 mesh; and / or, the mass ratio of the vegetable oil residue to the red mud is 0.5 - 2:

1.

7. The method according to claim 1 or 2, characterized in that, The time of the complexation reaction is 1 - 3 h; and / or, the complexation reaction is carried out under stirring conditions, and the rotation speed of the stirring is 30 - 35 r / min.

8. A vegetable oil residue modified red mud prepared by the method according to any one of claims 1 - 4.

9. An application of the vegetable oil residue modified red mud according to claim 8 in asphalt modification.

10. A modified asphalt, characterized in that, Modify the asphalt by adding the vegetable oil residue modified red mud according to claim 8; the addition amount of the vegetable oil residue modified red mud is 1 - 10% of the total mass of the modified asphalt.

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