A method for co-utilizing red mud and electrolytic manganese residue to prepare a catalytic material, its product and application

Abstract

The present invention discloses a method for co-utilizing red mud and electrolytic manganese slag to prepare a catalytic material, as well as its product and application. The method comprises the following steps: mixing electrolytic manganese slag and red mud, stirring evenly, adding ammonium chloride, stirring, adding hydrochloric acid solution, stirring, roasting, grinding; adding an auxiliary agent, stirring evenly, adding water, granulating, standing, performing hydrothermal reaction, roasting to obtain the catalytic material. The preparation process of the present invention is simple, the process flow is brief, and the required core raw materials are only red mud and electrolytic manganese slag, efficiently realizing the resource utilization of red mud and electrolytic manganese slag. The prepared catalytic material can rapidly adsorb pollutants in the waste liquid under the action of photocatalysis, and can further significantly improve the removal effects of COD, ammonia nitrogen, total phosphorus, and heavy metal mercury under photocatalytic conditions.

Description

Technical Field

[0001] The present invention relates to a method for co - utilizing red mud and electrolytic manganese slag to prepare a catalytic material, as well as its product and application, belonging to the field of resource utilization of industrial solid wastes. Background Art

[0002] Red mud and electrolytic manganese slag have significant acid - base complementary characteristics. During the preparation of the catalytic material, the strong alkalinity of red mud can neutralize the free sulfate and ammonia - nitrogen pollutants in electrolytic manganese slag, realizing the stable solidification of heavy metals. At the same time, the alkaline environment of red mud can promote the hydrolysis of silicate in siliceous - aluminous solid waste, accelerate the hydration reaction rate, improve the heavy - metal solidification effect, and provide new ideas for the treatment of industrial solid wastes.

[0003] The alkaline environment of red mud can also promote the hydrolysis of silicate in siliceous - aluminous solid waste, accelerate the hydration reaction rate, thereby improving the solidification effect of heavy metals. Through this co - treatment method, not only the pollution problems of red mud and electrolytic manganese slag are solved, but also it provides a reference for the treatment of other industrial solid wastes. Red mud and electrolytic manganese slag are rich in various metal oxides and have the basis of catalytic active substances. Red mud contains Fe2O3, Al2O3 and TiO2, which can provide redox active sites; electrolytic manganese slag contains MnO2 and sulfates, which have the ability of electron transfer. Through processes such as thermal activation and acid leaching purification, a supported multi - metal composite catalyst can be prepared for sewage treatment (such as Fenton catalysis) or VOCs degradation. The steel - slag - red - mud - manganese - slag co - system can significantly improve the hydration activity of the cementitious material, and the increase in the red - mud content can significantly improve the mechanical properties and cementitious activity of the material.

[0004] At present, there are certain limitations in using red mud and electrolytic manganese slag to prepare catalytic materials. On the one hand, traditional methods do not fully explore their synergistic effects, and most do not make full use of their acid - base complementary characteristics, resulting in poor performance of catalytic materials. On the other hand, existing processes are complex, costly, or have problems such as poor adaptability to raw materials and difficulties in large - scale production. For example, some methods require adding a large amount of chemical reagents or using special equipment, increasing production costs and process complexity; some other methods have strict requirements on the composition and properties of red mud and electrolytic manganese slag, restricting their wide application. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to provide a method for co - utilizing red mud and electrolytic manganese slag to prepare a catalytic material, as well as its product and application.

[0006] Technical Solution: To solve the above - mentioned technical problem, the present invention provides a method for co - utilizing red mud and electrolytic manganese slag to prepare a catalytic material, which includes the following steps:

[0007] (1) Mix electrolytic manganese residue and red mud, stir evenly to obtain red residue mud; mix ammonium chloride and red residue mud, stir evenly to obtain ammonium-loaded residue mud; mix hydrochloric acid solution and ammonium-loaded residue mud, stir evenly to obtain acid-leached residue mud, roast it, and grind it to obtain iron-removed powder;

[0008] (2) Mix an auxiliary agent and the iron-removed powder described in step (1), stir evenly to obtain hydrothermal raw material; the auxiliary agent includes any one of tetraethylammonium hydroxide, isopropylamine, triethylamine or diethylamine;

[0009] (3) Mix water and the hydrothermal raw material described in step (2), granulate, let it stand, carry out hydrothermal reaction, and roast to obtain a catalytic material.

[0010] Among them, the mass ratio of the electrolytic manganese residue and red mud described in step (1) is 40~120:100.

[0011] Among them, the mass ratio of the ammonium chloride and red residue mud described in step (1) is 2.5~17.5:100.

[0012] Among them, the liquid-solid ratio of the hydrochloric acid solution and ammonium-loaded residue mud described in step (1) is 0.2~0.6:1 mL / g.

[0013] Among them, the concentration of the hydrochloric acid solution described in step (1) is 2~6 M.

[0014] Among them, the roasting temperature in step (1) is 450~750 °C, and the time is 0.5~4.5 hours.

[0015] Among them, the grinding time in step (1) is 5~35 minutes.

[0016] Among them, the mass ratio of the auxiliary agent and iron-removed powder described in step (2) is 0.25~2.75:100.

[0017] Among them, the liquid-solid ratio of the water and hydrothermal raw material described in step (3) is 0.35~0.65:1 mL / g.

[0018] Among them, the hydrothermal reaction time in step (3) is 0.5~4.5 hours, and the temperature is 120~280 °C.

[0019] Among them, the roasting temperature in step (3) is 650~950 °C, and the time is 0.5~4.5 hours.

[0020] Among them, the standing time in step (3) is 1~3 days.

[0021] The present invention also provides a catalytic material prepared by the above method.

[0022] The present invention also provides the application of the catalytic material in removing pollutants.

[0023] Among them, the following steps are included: putting the catalytic material into the sample to be treated, stirring while irradiating with an ultraviolet lamp, centrifuging, and solid-liquid separation, then the sample after removing pollutants can be obtained.

[0024] Reaction mechanism: Roast the acid-leached residue sludge. In a high-temperature environment, chlorine in ammonium chloride and hydrochloric acid combines with iron and aluminum in red mud and electrolytic manganese slag to form ferric chloride and aluminum chloride and volatilize into the flue gas, while ammonium ions react with nitrogen oxides formed in the air to generate nitrogen. At the same time, during the roasting process, hydrogen ions in hydrochloric acid promote the release of titanium, manganese, and other trace metal elements in red mud and electrolytic manganese slag. High-temperature roasting improves the activity of regular salts and gypsum materials in red mud and electrolytic manganese slag through thermal activation, removing their free water and crystal water. Mix water and hydrothermal raw materials. During the stirring and standing process, the additives dissolve into the hydrothermal raw material particles and promote the reaction between silicate, ferric aluminate, and gypsum-based calcium materials in the activated red mud and electrolytic manganese slag through a structure-directing effect to form a solidified colloid, and induce hydrolysis of titanium, manganese, and other trace heavy metal elements to form coprecipitation and cement on the solidified body. Place the roasted raw material in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted particles. The structure-directing effect of the additives is strengthened, the silicate undergoes hydrolysis polymerization, and the self-excitation and self-cementation effect between it and ferric aluminate and gypsum-based calcium materials are more obvious. Titanium, manganese, and other trace heavy metal elements are fully hydrolyzed and intermingled.

[0025] Roast the hydrated material. In a high-temperature environment, the additives are oxidized to form carbon dioxide and water vapor and diffuse out of the cemented solidified body material. The titanium, manganese, and heavy metal coprecipitation mixture undergoes dehydration to form a mixed metal oxide and cement on the surface of the solidified body particles.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The preparation process of the present invention is simple, the process flow is brief, and the required core raw materials are only red mud and electrolytic manganese slag, efficiently realizing the resource utilization of red mud and electrolytic manganese slag. The prepared catalytic material can rapidly adsorb pollutants in the waste liquid without photocatalysis, and can further significantly improve the removal effects of COD, ammonia nitrogen, total phosphorus, and heavy metal mercury under photocatalytic conditions. Brief Description of the Drawings

[0027] Figure 1 It is a flow chart of the treatment method of the present invention. Detailed Embodiments

[0028] The technical solutions of the present invention will be further described below in conjunction with the drawings.

[0029] Preparation of landfill leachate and mercury-containing landfill leachate: The landfill leachate used in the experiment was taken from Zhuji Sanfeng Environmental Energy Co., Ltd. The COD mass concentration of this batch of landfill leachate was 4,152 mg / L, the total phosphorus concentration was 305 mg / L, and the ammonia nitrogen concentration was 1,075 mg / L. 500 mg of mercury was added to 1 L of landfill leachate and stirred evenly to prepare the mercury-containing landfill leachate.

[0030] Red mud: Provided by Shandong Zibo Zhengheng Aluminum Industry Co., Ltd., the main detected components include: 38.52% Fe2O3, 27.83% Al2O3, 12.49% SiO2, 11.36% Na2O, 5.61% TiO2, 0.57% CaO, 0.34% SO3 and other components (inevitable impurities and loss on ignition);

[0031] Electrolytic manganese residue: The electrolytic manganese residue was taken from Guizhou Nengkuang Manganese Industry Group Co., Ltd., mainly including 23.52% SO3, 13.17% SiO2, 15.21% CaO, 13.09% Fe2O3, 6.82% Al2O3, 10.21% MnO, 2.96% K2O, 1.55% MgO, 0.86% TiO2 and other components (inevitable impurities and loss on ignition).

[0032] Effect of mass ratio of electrolytic manganese residue to red mud on the performance of the prepared catalyst in Example 1

[0033] Mix electrolytic manganese residue and red mud according to the mass ratios of 25:100, 30:100, 35:100, 40:100, 80:100, 120:100, 130:100, 140:100, 150:100, stir evenly to obtain red slag mud. Mix ammonium chloride and red slag mud according to the mass ratio of 2.5:100, stir evenly to obtain ammonium-loaded slag mud. Mix hydrochloric acid solution and ammonium-loaded slag mud according to the liquid-solid ratio of 0.2:1 mL / g, stir evenly to obtain acid-leached slag mud, where the concentration of the hydrochloric acid solution is 2 M. Roast the acid-leached slag mud, and then grind the roasted slag to obtain de-iron powder, where the roasting temperature is 450 °C, the roasting time is 0.5 hours, and the grinding time is 5 minutes. Mix the additive and de-iron powder according to the mass ratio of 0.25:100, stir evenly to obtain hydrothermal raw material, where the additive is tetraethylammonium hydroxide. Mix water and hydrothermal raw material according to the liquid-solid ratio of 0.35:1 mL / g, granulate, and let stand for 1 day to obtain roasted raw pellets. Place the roasted raw material in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted raw pellets to obtain hydrated material, where the hydrothermal time is 0.5 hours and the hydrothermal temperature is 120 °C. Roast the hydrated material to obtain the catalytic material, where the roasting temperature is 650 °C and the roasting time is 0.5 hours.

[0034] Adsorption test: 1 g of the catalytic material was put into 1 L of landfill leachate, stirred at a speed of 120 rmp for 120 min, and then centrifuged at a speed of 5000 rpm for solid-liquid separation. The concentrations of different pollutants in the separated liquid were detected and the removal rates were calculated. The specific detection and calculation are as follows.

[0035] Detection of COD concentration and calculation of COD removal capacity: The chemical oxygen demand (COD) concentration of the leachate was determined according to the national standard "Water Quality - Determination of Chemical Oxygen Demand - Dichromate Method" (HJ 828-2017). The COD removal capacity was calculated according to formula (1), where R COD is the COD removal capacity (mg / g), C COD0 and C CODt are the COD concentrations (mg / L) of the landfill leachate before and after treatment respectively, m is the mass of the catalyst (1 g), and V is the volume of the landfill leachate (1 L).

[0036]

[0037] Detection of total phosphorus concentration and calculation of total phosphorus removal capacity: The total phosphorus concentration of the leachate was determined according to the standard "Water Quality - Determination of Phosphate and Total Phosphorus - Continuous Flow - Ammonium Molybdate Spectrophotometric Method" (HJ 670-2013). The total phosphorus removal rate was calculated according to formula (2), where R TP is the total phosphorus removal capacity (mg / g), c TP0 and c TPt are the total phosphorus concentrations (mg / L) of the landfill leachate before and after treatment respectively, m is the mass of the catalyst (1 g), and V is the volume of the landfill leachate (1 L).

[0038]

[0039] Detection of ammonia nitrogen concentration and calculation of ammonia nitrogen removal capacity: The concentration of ammonia nitrogen in the leachate was determined according to "Water Quality - Determination of Ammonia Nitrogen - Salicylic Acid Spectrophotometric Method" (HJ536-2009). The ammonia nitrogen removal capacity was calculated according to formula (3), where R N is the ammonia nitrogen removal capacity (mg / g), c N0 is the initial concentration of ammonia nitrogen in the leachate before treatment (mg / L), c Nt is the remaining concentration of ammonia nitrogen in the treated leachate (mg / L), m is the mass of the catalyst (1 g), and V is the volume of the landfill leachate (1 L).

[0040]

[0041] Mercury ion concentration detection and removal capacity calculation: The mercury ion concentration in the leachate was determined according to the "Determination of mercury, arsenic, selenium, bismuth and antimony in water - Atomic fluorescence spectrometry" (HJ 694 - 2014). The mercury ion removal capacity was calculated according to formula (4), where R Hg is the mercury ion removal capacity (mg / g), c Hg0 is the initial concentration of mercury ions in the leachate before treatment (mg / L), c Hgt is the concentration of mercury ions in the treated leachate (mg / L), m is the mass of the catalyst (1 g), and V is the volume of the landfill leachate (1 L).

[0042]

[0043] The test results of this example are shown in Table 1.

[0044] Table 1 Influence of the mass ratio of electrolytic manganese slag to red mud on the performance of the prepared catalyst

[0045]

[0046] As can be seen from Table 1, when the mass ratio of electrolytic manganese slag to red mud is less than 40:100 (as shown in Table 1, when the mass ratio of electrolytic manganese slag to red mud = 35:100, 30:100, 25:100 and lower ratios not listed in Table 1), less electrolytic manganese slag is added, and the reaction between electrolytic manganese slag and red mud is insufficient, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of electrolytic manganese slag to red mud decreases. When the mass ratio of electrolytic manganese slag to red mud is equal to 40 - 120:100 (as shown in Table 1, when the mass ratio of electrolytic manganese slag to red mud = 40:100, 80:100, 120:100), the acid-leached slag mud is roasted. In a high-temperature environment, chlorine in ammonium chloride and hydrochloric acid combines with iron and aluminum in red mud and electrolytic manganese slag to form ferric chloride and aluminum chloride and volatilize into the flue gas, while ammonium ions react with nitrogen oxides formed in the air to generate nitrogen. At the same time, during the roasting process, hydrogen ions in hydrochloric acid promote the release of titanium, manganese, and other trace metal elements in red mud and electrolytic manganese slag. High-temperature roasting enhances the activity of regular salts and gypsum materials in red mud and electrolytic manganese slag through thermal activation, removing free water and crystal water. Finally, the prepared catalyst has a COD removal capacity higher than 478 mg / g, a total phosphorus removal capacity higher than 32 mg / g, an ammonia nitrogen removal capacity higher than 69 mg / g, and a mercury removal capacity higher than 21 mg / g. When the mass ratio of electrolytic manganese slag to red mud is greater than 120:100 (as shown in Table 1, when the mass ratio of electrolytic manganese slag to red mud = 130:100, 140:100, 150:100 and higher ratios not listed in Table 1), excessive electrolytic manganese slag is added, and the reaction between electrolytic manganese slag and red mud is unbalanced, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of electrolytic manganese slag to red mud further increases. Generally speaking, considering the benefits and costs, when the mass ratio of electrolytic manganese slag to red mud is equal to 40 - 120:100, it is most beneficial to improve the performance of the prepared catalyst.

[0047] Effect of the mass ratio of ammonium chloride to red slag mud on the performance of the prepared catalyst in Example 2

[0048] Mix electrolytic manganese residue and red mud in a mass ratio of 120:100, stir evenly to obtain red residue mud. Mix ammonium chloride and red residue mud in mass ratios of 1:100, 1.5:100, 2:100, 2.5:100, 10:100, 17.5:100, 20:100, 22.5:100, 25:100, stir evenly to obtain ammonium-loaded residue mud. Mix hydrochloric acid solution and ammonium-loaded residue mud in a liquid-solid ratio of 0.4:1 mL / g, stir evenly to obtain acid-leached residue mud, where the concentration of the hydrochloric acid solution is 4 M. Roast the acid-leached residue mud, and then grind the roasted residue to obtain iron-removed powder, where the roasting temperature is 600 °C, the roasting time is 2.5 hours, and the grinding time is 20 minutes. Mix an auxiliary agent and the iron-removed powder in a mass ratio of 1.5:100, stir evenly to obtain hydrothermal raw material, where the auxiliary agent is isopropylamine. Mix water and the hydrothermal raw material in a liquid-solid ratio of 0.5:1 mL / g, granulate, and let it stand for 2 days to obtain roasted green pellets. Place the roasted green pellets in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 2.5 hours and the hydrothermal temperature is 200 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 800 °C and the roasting time is 2.5 hours.

[0049] The adsorption test, the detection of COD concentration and the calculation of COD removal capacity, the detection of total phosphorus concentration and the calculation of total phosphorus removal capacity, the detection of ammonia nitrogen concentration and the calculation of ammonia nitrogen removal capacity, and the detection of mercury ion concentration and the calculation of removal capacity are the same as in Example 1. The test results of this example are shown in Table 2.

[0050] Table 2 Influence of the mass ratio of ammonium chloride and red residue mud on the performance of the prepared catalyst

[0051]

[0052] As can be seen from Table 2, when the mass ratio of ammonium chloride to red mud residue is less than 2.5:100 (such as in Table 2, the mass ratio of ammonium chloride to red mud residue = 2:100, 1.5:100, 1:100 and lower ratios not listed in Table 2), less ammonium chloride is added, and the reaction between ammonium chloride and red mud residue is insufficient under high-temperature roasting conditions, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of ammonium chloride to red mud residue decreases. When the mass ratio of ammonium chloride to red mud residue is equal to 2.5 - 17.5:100 (such as in Table 2, the mass ratio of ammonium chloride to red mud residue = 2.5:100, 10:100, 17.5:100), the acid-leached slag mud is roasted. Under high-temperature conditions, the chlorine in ammonium chloride and hydrochloric acid combines with iron and aluminum in red mud and electrolytic manganese slag to form iron chloride and aluminum chloride and volatilize into the flue gas, while the ammonium ions react with nitrogen oxides formed in the air to produce nitrogen. At the same time, during the roasting process, the hydrogen ions in hydrochloric acid promote the release of titanium, manganese, and other trace metal elements in red mud and electrolytic manganese slag. High-temperature roasting enhances the activity of the regular salts and gypsum materials in red mud and electrolytic manganese slag through thermal activation, removing free water and crystal water. Finally, the prepared catalyst has a COD removal capacity higher than 512 mg / g, a total phosphorus removal capacity higher than 38 mg / g, an ammonia nitrogen removal capacity higher than 77 mg / g, and a mercury removal capacity higher than 26 mg / g. When the mass ratio of ammonium chloride to red mud residue is greater than 17.5:100 (such as in Table 2, the mass ratio of ammonium chloride to red mud residue = 20:100, 22.5:100, 25:100 and higher ratios not listed in Table 2), excessive ammonium chloride is added, and the reaction between ammonium chloride and red mud residue is unbalanced under high-temperature roasting conditions, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of ammonium chloride to red mud residue further increases. Generally speaking, considering the combination of benefits and costs, when the mass ratio of ammonium chloride to red mud residue is equal to 2.5 - 17.5:100, it is most beneficial to improve the performance of the prepared catalyst.

[0053] Effect of the mass ratio of the additive and iron-removing powder in Example 3 on the performance of the prepared catalyst

[0054] Mix electrolytic manganese residue and red mud in a mass ratio of 120:100, stir evenly to obtain red residue mud. Mix ammonium chloride and red residue mud in a mass ratio of 17.5:100, stir evenly to obtain ammonium-loaded residue mud. Mix hydrochloric acid solution and ammonium-loaded residue mud in a liquid-solid ratio of 0.6:1 mL / g, stir evenly to obtain acid-leached residue mud, where the concentration of the hydrochloric acid solution is 6 M. Roast the acid-leached residue mud, and then grind the roasted residue to obtain iron-removed powder, where the roasting temperature is 750 °C, the roasting time is 4.5 hours, and the grinding time is 35 minutes. Mix additives and iron-removed powder in mass ratios of 0.1:100, 0.15:100, 0.2:100, 0.25:100, 1.5:100, 2.75:100, 3:100, 3.25:100, 3.5:100, stir evenly to obtain hydrothermal raw material, where the additive is triethylamine. Mix water and hydrothermal raw material in a liquid-solid ratio of 0.65:1 mL / g, granulate, and let stand for 3 days to obtain roasted green pellets. Place the roasted green pellets in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 4.5 hours and the hydrothermal temperature is 280 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 950 °C and the roasting time is 4.5 hours.

[0055] The adsorption test, the detection of COD concentration and the calculation of COD removal capacity, the detection of total phosphorus concentration and the calculation of total phosphorus removal capacity, the detection of ammonia nitrogen concentration and the calculation of ammonia nitrogen removal capacity, and the detection of mercury ion concentration and the calculation of removal capacity are the same as those in Example 1. The test results of this example are shown in Table 3.

[0056] Table 3 Influence of the mass ratio of additives and iron-removed powder on the performance of the prepared catalyst

[0057]

[0058] As can be seen from Table 3, when the mass ratio of the additive to the iron-removing powder is less than 0.25:100 (as in Table 3, when the mass ratio of the additive to the iron-removing powder = 0.2:100, 0.15:100, 0.1:100 and lower ratios not listed in Table 3), less additive is added and the reaction between the additive and the iron-removing powder is insufficient, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of the additive to the iron-removing powder decreases. When the mass ratio of the additive to the iron-removing powder is equal to 0.25 - 2.75:100 (as in Table 3, when the mass ratio of the additive to the iron-removing powder = 0.25:100, 1.5:100, 2.75:100), during the mixing of the mixed water and the hydrothermal raw material, stirring, and standing, the additive dissolves into the hydrothermal raw material particles and promotes the reaction between the silicate, ferroaluminate, and gypsum-based calcium materials in the activated red mud and electrolytic manganese slag through a structure-directing effect to form a solidified colloid, and induces the hydrolysis of titanium, manganese, and other trace heavy metal elements to form coprecipitation and cement on the solidified body. When the calcined raw material is placed in a hydrothermal autoclave for hydrothermal reaction of the calcined particles, the structure-directing effect of the additive is strengthened, the silicate undergoes hydrolysis polymerization, and the self-excitation and self-cementation effect between it and the ferroaluminate and gypsum-based calcium materials become more obvious. Titanium, manganese, and other trace heavy metal elements are fully hydrolyzed and intermingled. After calcining the hydrated material, the additive is oxidized to form carbon dioxide and water vapor at high temperature and diffuses out of the cemented solidified body material. The coprecipitation mixture of titanium, manganese, and heavy metals undergoes dehydration to form a mixed metal oxide and cement on the surface of the solidified body particles. Finally, the prepared catalyst has a COD removal capacity higher than 538 mg / g, a total phosphorus removal capacity higher than 46 mg / g, an ammonia nitrogen removal capacity higher than 85 mg / g, and a mercury removal capacity higher than 32 mg / g. When the mass ratio of the additive to the iron-removing powder is greater than 2.75:100 (as in Table 3, when the mass ratio of the additive to the iron-removing powder = 3:100, 3.25:100, 3.5:100 and higher ratios not listed in Table 3), excessive additive is added and the reaction between the additive and the iron-removing powder is unbalanced, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared catalyst as the mass ratio of the additive to the iron-removing powder further increases.

[0059] Generally speaking, considering the benefits and costs, when the mass ratio of the additive to the iron-removing powder is equal to 0.25 - 2.75:100, it is most beneficial to improve the performance of the prepared catalyst.

[0060] Comparison of Catalyst Performance under Light Irradiation Conditions in Example 4

[0061] Mix electrolytic manganese slag and red mud in a mass ratio of 80:100, stir evenly to obtain red slag mud. Mix ammonium chloride and red slag mud in a mass ratio of 2.5:100, stir evenly to obtain ammonium-loaded slag mud. Mix hydrochloric acid solution and ammonium-loaded slag mud in a liquid-solid ratio of 0.6:1 mL / g, stir evenly to obtain acid-leached slag mud, where the concentration of the hydrochloric acid solution is 6 M. Roast the acid-leached slag mud, and then grind the roasted slag to obtain iron-removed powder, where the roasting temperature is 450 °C, the roasting time is 2.5 hours, and the grinding time is 35 minutes. Mix the auxiliary agent and the iron-removed powder in a mass ratio of 2.75:100, stir evenly to obtain hydrothermal raw material, where the auxiliary agent is diethylamine. Mix water and the hydrothermal raw material in a liquid-solid ratio of 0.65:1 mL / g, granulate, and let it stand for 3 days to obtain roasted green pellets. Place the roasted raw material in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 4.5 hours and the hydrothermal temperature is 120 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 950 °C and the roasting time is 2.5 hours.

[0062] Photocatalytic removal test: Put 1 g of the catalytic material into 1 L of landfill leachate, stir at a speed of 120 rmp while irradiating with an ultraviolet lamp for 120 min, and then centrifuge at a speed of 5000 rpm for solid-liquid separation. Detect the concentrations of different pollutants in the separated liquid and calculate the removal rate. The specific detection and calculation are the same as in Example 1.

[0063] The adsorption test, the detection of COD concentration and the calculation of COD removal capacity, the detection of total phosphorus concentration and the calculation of total phosphorus removal capacity, the detection of ammonia nitrogen concentration and the calculation of ammonia nitrogen removal capacity, and the detection of mercury ion concentration and the calculation of removal capacity are all the same as in Example 1.

[0064] The test results of this example are shown in Table 4.

[0065] Table 4 Comparison of catalyst performance under light irradiation conditions

[0066]

[0067] As can be seen from Table 4, under photocatalytic conditions, the removal effects of the catalyst on COD, ammonia nitrogen, total phosphorus, and heavy metal mercury can be further significantly improved.

[0068] Comparative example Influence of different processes on the performance of the prepared catalyst

[0069] Process of the present invention: Mix electrolytic manganese residue and red mud in a mass ratio of 40:100, stir evenly to obtain red residue mud. Mix ammonium chloride and red residue mud in a mass ratio of 10:100, stir evenly to obtain ammonium-loaded residue mud. Mix hydrochloric acid solution and ammonium-loaded residue mud in a liquid-solid ratio of 0.6:1 mL / g, stir evenly to obtain acid-leached residue mud, where the concentration of the hydrochloric acid solution is 2 M. Roast the acid-leached residue mud, and then grind the roasted residue to obtain iron-removed powder, where the roasting temperature is 750 °C, the roasting time is 4.5 hours, and the grinding time is 35 minutes. Mix an auxiliary agent and the iron-removed powder in a mass ratio of 2.75:100, stir evenly to obtain hydrothermal raw material, where the auxiliary agent is diethylamine. Mix water and the hydrothermal raw material in a liquid-solid ratio of 0.35:1 mL / g, granulate, and let stand for 3 days to obtain roasted green pellets. Place the roasted green pellets in a hydrothermal autoclave to conduct hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 4.5 hours and the hydrothermal temperature is 280 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 950 °C and the roasting time is 4.5 hours.

[0070] Comparative process 1: Mix ammonium chloride and red mud in a mass ratio of 10:100, stir evenly to obtain ammonium-loaded mud. Mix hydrochloric acid solution and ammonium-loaded mud in a liquid-solid ratio of 0.6:1 mL / g, stir evenly to obtain acid-leached mud, where the concentration of the hydrochloric acid solution is 2 M. Roast the acid-leached mud, and then grind the roasted residue to obtain iron-removed powder, where the roasting temperature is 750 °C, the roasting time is 4.5 hours, and the grinding time is 35 minutes. Mix an auxiliary agent and the iron-removed powder in a mass ratio of 2.75:100, stir evenly to obtain hydrothermal raw material, where the auxiliary agent is diethylamine. Mix water and the hydrothermal raw material in a liquid-solid ratio of 0.35:1 mL / g, granulate, and let stand for 3 days to obtain roasted green pellets. Place the roasted green pellets in a hydrothermal autoclave to conduct hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 4.5 hours and the hydrothermal temperature is 280 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 950 °C and the roasting time is 4.5 hours.

[0071] Comparative Process 2: Mix electrolytic manganese slag and red mud in a mass ratio of 40:100, stir evenly to obtain red slag mud. Mix ammonium chloride and red slag mud in a mass ratio of 10:100, stir evenly to obtain ammonium-loaded slag mud. Mix hydrochloric acid solution and ammonium-loaded slag mud in a liquid-solid ratio of 0.6:1 mL / g, stir evenly to obtain acid-leached slag mud, where the concentration of the hydrochloric acid solution is 2 M. Roast the acid-leached slag mud, and then grind the roasted slag to obtain iron-removed powder, where the roasting temperature is 750 °C, the roasting time is 4.5 hours, and the grinding time is 35 minutes. Mix water and iron-removed powder in a liquid-solid ratio of 0.35:1 mL / g, granulate, and let stand for 3 days to obtain roasted green pellets. Place the roasted green pellets in a hydrothermal autoclave to carry out hydrothermal reaction on the roasted green pellets to obtain hydrated material, where the hydrothermal time is 4.5 hours and the hydrothermal temperature is 280 °C. Roast the hydrated material to obtain a catalytic material, where the roasting temperature is 950 °C and the roasting time is 4.5 hours.

[0072] The photocatalytic removal test is the same as in Example 3, and the specific detection and calculation are the same as in Example 1.

[0073] The test results of this comparative example are shown in Table 5.

[0074] Table 5 Influence of different processes on the performance of the prepared catalyst

[0075]

[0076] As can be seen from Table 5, the catalyst prepared by the process of the present invention has significantly higher removal effects on COD, ammonia nitrogen, total phosphorus, and heavy metal mercury than Comparative Process 1 and Comparative Process 2.

Claims

1. A method for co-utilizing red mud and electrolytic manganese slag to prepare a catalytic material, characterized in that, It includes the following steps: (1) Mix electrolytic manganese residue and red mud, stir evenly to obtain red residue mud; mix ammonium chloride and red residue mud, stir evenly to obtain ammonium-loaded residue mud; mix hydrochloric acid solution and ammonium-loaded residue mud, stir evenly to obtain acid-leached residue mud, roast it, and grind it to obtain iron-removed powder; the mass ratio of the electrolytic manganese residue to the red mud is 40-120:100; the mass ratio of the ammonium chloride to the red residue mud is 2.5-17.5:100; the roasting temperature is 450-750 °C, and the time is 0.5-4.5 hours; (2) Mix an auxiliary agent and the iron-removed powder in step (1), stir evenly to obtain hydrothermal raw material; the auxiliary agent includes any one of tetraethylammonium hydroxide, isopropylamine, triethylamine or diethylamine; the mass ratio of the auxiliary agent to the iron-removed powder is 0.25-2.75:100; (3) Mix water and the hydrothermal raw material in step (2), granulate, let it stand, carry out hydrothermal reaction, and roast to obtain a catalytic material.

2. The method according to claim 1, wherein In step (1), the liquid-solid ratio of the hydrochloric acid solution to the ammonium-loaded residue mud is 0.2-0.6:1 mL / g.

3. The method according to claim 1, wherein In step (1), the concentration of the hydrochloric acid solution is 2-6 M.

4. The method according to claim 1, characterized in that, In step (1), the grinding time is 5-35 minutes.

5. The method according to claim 1, wherein In step (3), the liquid-solid ratio of the water to the hydrothermal raw material is 0.35-0.65:1 mL / g.

6. The method according to claim 1, wherein In step (3), the hydrothermal reaction time is 0.5-4.5 hours, and the temperature is 120-280 °C.

7. The method according to claim 1, characterized in that, In step (3), the roasting temperature is 650-950 °C, and the time is 0.5-4.5 hours.

8. A catalytic material prepared by the method according to any one of claims 1 to 7.

9. Application of the catalytic material according to claim 8 in removing pollutants.

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