A method for preparing ozone catalyst using hot-rolled sludge
By preparing ozone catalysts from hot-rolled sludge and utilizing its heavy metal and organic components to form redox active sites, the problem of the difficulty in resource utilization and harmless treatment of hot-rolled sludge is solved, achieving low-cost and high-efficiency catalyst preparation and organic matter degradation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANGANG STEEL CO LTD
- Filing Date
- 2024-03-07
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies have failed to effectively utilize hot-rolled sludge from the steel industry to prepare ozone catalysts, making it difficult to recycle and render harmless, and resulting in high costs.
After drying and pulverizing hot-rolled sludge, a binder is added, and the mixture is granulated and sintered at high temperature to prepare an ozone catalyst with catalytic activity. The heavy metals and organic components in the hot-rolled sludge form redox active sites.
This study achieved low-cost preparation of a high-efficiency ozone catalyst, promoted electron transfer catalytic activation of ozone to generate hydroxyl radicals, improved the degradation efficiency of organic matter, and realized the reduction and resource utilization of oil sludge.
Abstract
Description
Technical Field
[0001] This invention relates to ozone catalysts for wastewater treatment, specifically a method for preparing ozone catalysts based on metallurgical solid waste. Background Technology
[0002] Ozone catalytic oxidation technology utilizes a catalyst to catalyze ozone to generate highly oxidizing hydroxyl radicals (·OH), thereby rapidly degrading organic matter in water. Due to its advantages such as being clean and pollution-free, having high oxidation efficiency, and being simple to operate, it has become one of the key technologies for removing highly stable and recalcitrant organic matter from wastewater and has gained increasing popularity in advanced wastewater treatment.
[0003] In the steel industry, a large amount of iron-containing solid waste is generated, most notably the oily iron sludge in the horizontal flow pool of hot rolling mills. Iron oxide scale generated during hot rolling is washed off by high-pressure water into drainage ditches. After passing through a cyclone well, it settles in the horizontal flow pool. These fine iron scale particles, carrying lubricating oil, rolling oil, and water, settle to the bottom of the pool, forming hot-rolled sludge. Hot-rolled sludge is mainly bottom sediment from the horizontal flow pool, containing water, oil, and iron oxides, with a dry basis oil content generally ranging from 5% to 20%. Related literature reports that the oil in hot-rolled sludge contains 55% alkanes and alkenes, and 22% carboxylic acids, ketones, and aromatic hydrocarbons. The total iron content of hot-rolled sludge after burning is generally 67% to 72%. Due to differences in hot rolling process equipment and other factors, the oil consumption per ton of billet varies, resulting in a large fluctuation in the oil content of hot-rolled sludge. Because of its high oil content, this type of hot-rolled sludge is difficult to recycle directly.
[0004] Currently, some methods for preparing ozone catalysts using solid waste have been disclosed, such as CN 113713818 A, which discloses a solid waste-based heterogeneous ozone catalyst and its preparation method; CN 112191248 A, which discloses a catalyst for ozone oxidation treatment of wastewater containing solid waste without incineration and its preparation method; and CN 114749186 A, which discloses a method for preparing and applying a hydrothermally supported sludge carbon-based catalyst. However, no reports have been found on the preparation of ozone catalysts using hot-rolled sludge containing iron from the steel industry. Summary of the Invention
[0005] In view of this, the present invention provides a method for preparing ozone catalyst using hot-rolled sludge, which solves the problems of harmlessness, volume reduction and resource utilization of hot-rolled sludge, and provides a new production route for ozone catalyst with low cost and good catalytic performance.
[0006] To achieve the above-mentioned objective, the method for preparing an ozone catalyst using hot-rolled sludge includes the following steps:
[0007] Hot-rolled sludge is dried and pulverized into solid powder. Water and binder are added to the solid powder and mixed evenly. The mixed material is made into granules and dried. The dried granules are sintered to obtain the ozone catalyst.
[0008] In this disclosure and possible embodiments, the binder is asphalt tailings;
[0009] The softening point of the asphalt tailings is 82.8℃~106℃, the coking value is 48.3~55.2%, the ash content is 0.59~1.73%, the volatile content is 48.9~58.4%, the toluene insoluble content is 24.1~29.2%, and the quinoline insoluble content is 5.8~14.6%.
[0010] In this disclosure and possible embodiments, the sintering method includes:
[0011] The granular material is placed in a high-temperature dry distillation apparatus and sintered into the ozone catalyst under conditions of air isolation, temperature of 850℃~1150℃, and heat preservation for 10h~20h.
[0012] In this disclosure and possible embodiments, the method of isolating air is to place the granular material in a sealed crucible and then place the sealed crucible in the high-temperature dry distillation apparatus; or to place the granular material in the high-temperature dry distillation apparatus and isolate the air by introducing nitrogen gas.
[0013] In this disclosure and possible embodiments, the water accounts for 2% to 4% of the total mass of the solid powder, the water, and the binder, and the binder accounts for 2% to 6% of the total mass.
[0014] In this disclosure and possible embodiments, the granules are made by pressurizing the mixed material using a granulation device, with the applied pressure being 2 MPa to 10 MPa.
[0015] In this disclosure and possible embodiments, the diameter of the granules is 4 mm to 8 mm.
[0016] In this disclosure and possible embodiments, the temperature for drying the granules is 80°C to 90°C.
[0017] In this disclosure and possible embodiments, the hot-rolled sludge is dried at a temperature of 150–190°C, and the dried hot-rolled sludge is ground by a pulverizing mill and then sieved to 0.3 mm or less to obtain the solid powder.
[0018] In this disclosure and possible embodiments, the hot-rolled sludge, by mass percentage, has an oil content of 5%–15%, a water content of 15%–25%, a total iron content of 60%–75%, a silicon dioxide content of 0.5%–1.5%, an aluminum oxide content of 0.1%–0.8%, a calcium oxide content of 0.1%–0.4%, a magnesium oxide content of 0.05%–0.2%, and a manganese oxide content of 0.2%–1%.
[0019] The beneficial effects of this invention are:
[0020] The present invention provides a method for preparing ozone catalysts using hot-rolled sludge. This method leverages the fact that hot-rolled sludge contains various heavy metals and organic compounds. These components, after being subjected to high temperatures, form oxygen-containing functional groups with redox activity, as well as transition metals and their oxides. These components are dispersed and stabilized within the ozone catalyst, promoting electron transfer and catalytically activating ozone and other oxidants to generate hydroxyl radicals. Furthermore, hot-rolled sludge contains a large amount of iron and small amounts of silicon, aluminum, calcium, magnesium, and manganese, which can serve as active components of the catalyst. Therefore, the preparation of ozone catalysts using hot-rolled sludge provides a new, low-cost production route for ozone catalysts with excellent catalytic performance, while simultaneously achieving the reduction, resource recovery, and harmlessness of hot-rolled sludge. Detailed Implementation
[0021] The present disclosure is described below based on embodiments; however, it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, certain specific details are described in detail. However, those skilled in the art will fully understand the present disclosure for the parts not described in detail.
[0022] This disclosure further illustrates the method for preparing ozone catalysts using hot-rolled sludge according to the present invention through the following embodiments. The specific steps of preparing ozone catalysts using hot-rolled sludge in the following embodiments are summarized as follows:
[0023] (1) Drying: The hot-rolled sludge is placed in an oven and dried at a temperature of 150°C to 190°C. The drying temperature used in the following embodiments of this disclosure is 150°C to 190°C, in order to decompose and carbonize the oily substances, so as to facilitate the next step of processing.
[0024] (2) Grinding: The dried hot-rolled sludge is ground by a pulverizing mill and then sieved to 0.3 mm or less to obtain solid powder;
[0025] (3) Mixing: Add water (total mass of solid powder + water + binder) of 2% to 4% and binder of 2% to 6% by mass to the solid powder in sequence, and then mix for 1 to 2 hours using a mixer;
[0026] The binder used in the following embodiments of this disclosure is asphalt tailings, which are solid at room temperature, facilitating uniform mixing with solid powder. The softening point of the asphalt tailings is 82.8℃~106℃, the coking value is 48.3~55.2%, the ash content is 0.59~1.73%, the volatile content is 48.9~58.4%, the toluene-insoluble content is 24.1~29.2%, and the quinoline-insoluble content is 5.8~14.6%.
[0027] (4) Pelletizing: The well-mixed material is granulated under pressure using granulation equipment. The pressure applied is 2MPa to 10MPa, and the diameter of the granules obtained by granulation is 4mm to 8mm.
[0028] (5) Drying: Place the granular material in an oven and dry it at 80℃~90℃.
[0029] (6) Sintering: The dried granules are placed in a sealed graphite crucible, which is then placed in a high-temperature dry distillation apparatus, or the granules are placed directly in a high-temperature dry distillation apparatus under nitrogen atmosphere protection. High-temperature dry distillation is carried out at a temperature of 850 to 1150°C to carbonize the granules. The high-temperature dry distillation time is 10 to 20 hours.
[0030] Example 1
[0031] (1) The hot-rolled sludge is placed in an oven and dried at 160°C to allow the oily substances in the hot-rolled sludge to be fully decomposed and carbonized.
[0032] (2) The dried hot-rolled sludge is ground by a pulverizing mill and then sieved to 0.3 mm or less to obtain solid powder;
[0033] (3) Add water (2% by mass, total mass of solid powder + water + binder) and asphalt tailings (3% by mass) to the solid powder in sequence, and then mix with a mixer for 1 hour;
[0034] (4) Use a granulation equipment to pressurize the well mixed material. The pressure is 3MPa and the diameter of the granules obtained is 5mm.
[0035] (5) Place the granular material in an oven and dry it at 80°C.
[0036] (6) The dried granules are placed in a sealed graphite crucible, which is then placed in a high-temperature dry distillation apparatus, or the granules are placed directly in a high-temperature dry distillation apparatus protected by a nitrogen atmosphere. The granules are then carbonized at a temperature of 900°C. After a high-temperature dry distillation time of 10 hours, the ozone catalyst of Example 1 of this disclosure is obtained.
[0037] (7) The ozone catalyst of Example 1 of this disclosure was filled into the catalytic oxidation tower. A quinoline concentration of 80 mg / L aqueous solution was used as simulated wastewater. The wastewater volume was 600 ml, the catalyst dosage was 60 g, the ozone generator power was 12.6%, the ozone flow rate was 1.0 L / min, and the reaction time was 30 min. The results showed that after catalytic ozone oxidation, the removal rate of quinoline could reach 82.3%, which was more than 30% higher than the pollutant removal efficiency of ozone oxidation alone without catalyst.
[0038] Example 2
[0039] (1) The hot-rolled sludge is placed in an oven and dried at 180°C to allow the oily substances in the hot-rolled sludge to be fully decomposed and carbonized.
[0040] (2) The dried hot-rolled sludge is ground by a pulverizing mill and then sieved to 0.3 mm or less to obtain solid powder;
[0041] (3) Add water (3% by mass) and asphalt tailings (5% by mass) to the solid powder in sequence, and mix for 2 hours using a mixer;
[0042] (4) Use a granulation equipment to pressurize the well mixed material. The pressure is 8MPa and the diameter of the granules obtained is 7mm.
[0043] (5) Place the granular material in an oven and dry it at 90°C.
[0044] (6) The dried granules are placed in a sealed graphite crucible, which is then placed in a high-temperature dry distillation apparatus, or the granules are placed directly in a high-temperature dry distillation apparatus protected by a nitrogen atmosphere. The granules are then carbonized at a temperature of 1100°C. After a high-temperature dry distillation time of 20 hours, the ozone catalyst of Example 2 of this disclosure is obtained.
[0045] (7) The ozone catalyst of Example 2 of this disclosure was filled into the catalytic oxidation tower. A quinoline concentration of 80 mg / L aqueous solution was used as simulated wastewater. The wastewater volume was 600 ml, the catalyst dosage was 60 g, the ozone generator power was 12.6%, the ozone flow rate was 1.0 L / min, and the reaction time was 30 min. The results showed that after catalytic ozone oxidation, the removal rate of quinoline could reach 84.9%, which was more than 30% higher than the catalytic efficiency of the catalytic ozone oxidation process without catalyst.
[0046] The embodiments described above are merely illustrative of implementation methods of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent disclosure. It should be noted that those skilled in the art can make various modifications, equivalent substitutions, and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent disclosure should be determined by the appended claims.
Claims
1. A method for preparing an ozone catalyst using a hot rolling oil sludge, characterized by, include: Hot-rolled sludge is dried and pulverized into solid powder. Water and binder are added to the solid powder and mixed evenly. The mixed material is made into granules and dried. The dried granules are sintered to obtain the ozone catalyst. The binder is asphalt tailings; The softening point of the asphalt tailings is 82.8℃~106℃, the coking value is 48.3~55.2%, the ash content is 0.59~1.73%, the volatile matter is 48.9~58.4%, the toluene-insoluble matter is 24.1~29.2%, and the quinoline-insoluble matter is 5.8~14.6%. Based on mass percentage, the hot-rolled sludge contains 5%~15% oil, 15%~25% water, 60%~75% total iron, 0.5%~1.5% silicon dioxide, 0.1%~0.8% aluminum oxide, 0.1%~0.4% calcium oxide, 0.05%~0.2% magnesium oxide, and 0.2%~1% manganese oxide. The sintering method includes: The granular material is placed in a high-temperature dry distillation apparatus and sintered into the ozone catalyst under conditions of air isolation, temperature of 850℃~1150℃, and heat preservation for 10h~20h.
2. The method for preparing ozone catalyst using hot-rolled sludge according to claim 1, characterized in that: The method of isolating the air involves placing the granular material in a sealed crucible and then placing the crucible in the high-temperature dry distillation apparatus; or placing the granular material in the high-temperature dry distillation apparatus and isolating the air by introducing nitrogen gas.
3. The method for preparing an ozone catalyst using hot-rolled sludge according to claim 1 or 2, characterized in that: In the total mass of the solid powder, the water, and the binder, the water accounts for 2% to 4% of the mass, and the binder accounts for 2% to 6% of the mass.
4. The method for preparing an ozone catalyst using hot-rolled sludge according to claim 3, characterized in that: The granules are made by pressurizing and granulating the mixed material using a granulation device, with the applied pressure being 2MPa to 10MPa.
5. The method for preparing an ozone catalyst using hot-rolled sludge according to claim 1, 2, or 4, characterized in that: The diameter of the granules is 4 mm to 8 mm.
6. The method for preparing an ozone catalyst using hot-rolled sludge according to claim 5, characterized in that: The temperature for drying the granules is 80℃~90℃.
7. The method for preparing an ozone catalyst using hot-rolled sludge according to claim 1, 2, 4 or 6, characterized in that: The hot-rolled sludge is dried at a temperature of 150~190℃, and the dried hot-rolled sludge is ground by a pulverizing mill and then sieved to 0.3mm or less to obtain the solid powder.