A fly ash sequestering agent and a method of making the same
By preparing a fly ash chelating agent containing sodium dodecylbenzenesulfonate, sodium sulfide, lanthanum chloride, and other components, the problems of low heavy metal ion removal efficiency and poor stability in the existing technology were solved, and efficient treatment under low temperature and acidic environments was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN RUIXINDA ECOLOGICAL TECH CO LTD
- Filing Date
- 2024-01-19
- Publication Date
- 2026-06-16
AI Technical Summary
Existing fly ash chelating agents are inefficient in treating heavy metal chromium and zinc ions, and have poor stability in low-temperature and acidic environments, which limits the efficiency of fly ash treatment.
A fly ash chelating agent was prepared by mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier with stirring to enhance the removal effect of heavy metal ions and improve acid corrosion resistance and temperature stability.
It significantly improved the removal rate of heavy metal ions by fly ash chelating agent under low temperature and acidic environments, and enhanced the product's compatibility and stability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of fly ash chelating agents, specifically to a fly ash chelating agent and its preparation method. Background Technology
[0002] Fly ash from municipal solid waste incineration is a product collected during the incineration of municipal solid waste for power generation, found in flue gas ducts, flue gas purification devices, cyclone separators, and bag filters. It is a lightweight, small-particle-size powdery substance in ash form. Fly ash contains high levels of soluble heavy metals and dissolved salts; compared to the original waste, the content of toxic elements in municipal solid waste incineration ash is 10 to 100 times higher than in ordinary soil. Fly ash is classified as hazardous waste. Pb, Cd, Hg, and Zn are the main heavy metal pollutants in fly ash. It also contains small amounts of organic pollutants such as dioxins and furans, posing a risk of environmental pollution and harm to human health (twelve heavy metals and dioxins). Therefore, the National Hazardous Waste List classifies solid waste incineration fly ash as hazardous waste (number HW18). It is evident that fly ash generated after waste incineration must be disposed of as hazardous waste, and domestic and international case studies show that chemical stabilization can meet these requirements.
[0003] Existing fly ash chelating agents have difficulty achieving coordinated improvement in the treatment of heavy metal chromium and zinc ions. At the same time, the products inhibit treatment efficiency in low-temperature and acidic environments, thus limiting the efficiency of fly ash treatment. Summary of the Invention
[0004] In view of the deficiencies of the prior art, the purpose of this invention is to provide a fly ash chelating agent and its preparation method to solve the problems mentioned in the background art.
[0005] The present invention solves the technical problem by adopting the following technical solution:
[0006] This invention provides a fly ash chelating agent, comprising the following raw materials in parts by weight:
[0007] Sodium dodecylbenzenesulfonate solution 25-30 parts, sodium sulfide 10-15 parts, dithiocarbamate 5-10 parts, lanthanum chloride solution 3-6 parts, silicon carbide whisker agent 2-4 parts, hydroxyapatite modifier 1-3 parts.
[0008] Preferably, the fly ash chelating agent comprises the following raw materials in parts by weight:
[0009] Sodium dodecylbenzenesulfonate solution 27.5 parts, sodium sulfide 12.5 parts, dithiocarbamate 7.5 parts, lanthanum chloride solution 4.5 parts, silicon carbide whisker agent 3 parts, hydroxyapatite modifier 2 parts.
[0010] Preferably, the sodium dodecylbenzenesulfonate solution has a mass fraction of 10-15%; and the lanthanum chloride solution has a mass fraction of 2-5%.
[0011] Preferably, the preparation method of the silicon carbide whisker agent is as follows:
[0012] S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry. Then, preheat the dried silicon carbide whiskers at 55~60℃ for 5-10 minutes and keep them warm.
[0013] S02: 3-5 parts of heat-insulated silicon carbide whiskers, 1-3 parts of nano-silica sol, 1-2 parts of stearic acid and 4-8 parts of sodium silicate solution are ball-milled at a speed of 750-850 r / min for 1-2 h. After ball milling, whisker slurry is obtained.
[0014] S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:7. Finally, filter and dry to obtain silicon carbide whisker agent.
[0015] Preferably, the potassium permanganate solution has a mass fraction of 10-15%.
[0016] Preferably, the sodium silicate solution has a mass fraction of 8-12%.
[0017] Preferably, the immersion pressure of the immersion treatment is 10~15MPa, and the immersion time is 20~30min.
[0018] Preferably, the preparation method of the hydroxyapatite modifier is as follows:
[0019] S101: Heat-treat hydroxyapatite at 210~230℃ for 10~15min, then cool it to 55℃ at a rate of 2~4℃ / min and hold it at that temperature;
[0020] S102: 3-5 parts of heat-insulating hydroxyapatite, 2-4 parts of titanate coupling agent, 1-3 parts of glycolic acid and 6-10 parts of 15% sodium lignosulfonate solution are stirred together. After stirring, the mixture is washed with water and dried to obtain the hydroxyapatite modifier.
[0021] Preferably, the stirring speed of the stirring process is 450~500 r / min, and the stirring time is 20~30 min.
[0022] The present invention also provides a method for preparing a fly ash chelating agent, comprising the following steps: sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier raw materials to obtain a fly ash chelating agent.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] The fly ash chelating agent of the present invention uses sodium dodecylbenzenesulfonate solution, sodium sulfide, and dithiocarbamate as fly ash chelating agent base materials. By adding silicon carbide whisker agent and hydroxyapatite modifier, the two achieve synergistic effects, enhancing the coordinated removal effect of chromium and zinc ions, as well as the acid corrosion resistance and temperature stability of the product. In addition, the combination with lanthanum chloride solution further improves the performance of the product. The raw materials are synergistically formulated to jointly enhance the coordinated removal of chromium and zinc ions and the performance stability of the product. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. 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 skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] A fly ash chelating agent according to this embodiment comprises the following raw materials in parts by weight:
[0027] Sodium dodecylbenzenesulfonate solution 25-30 parts, sodium sulfide 10-15 parts, dithiocarbamate 5-10 parts, lanthanum chloride solution 3-6 parts, silicon carbide whisker agent 2-4 parts, hydroxyapatite modifier 1-3 parts.
[0028] The fly ash chelating agent in this embodiment comprises the following raw materials in parts by weight:
[0029] Sodium dodecylbenzenesulfonate solution 27.5 parts, sodium sulfide 12.5 parts, dithiocarbamate 7.5 parts, lanthanum chloride solution 4.5 parts, silicon carbide whisker agent 3 parts, hydroxyapatite modifier 2 parts.
[0030] In this embodiment, the sodium dodecylbenzenesulfonate solution has a mass fraction of 10-15%; the lanthanum chloride solution has a mass fraction of 2-5%.
[0031] The preparation method of the silicon carbide whisker agent in this embodiment is as follows:
[0032] S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry. Then, preheat the dried silicon carbide whiskers at 55~60℃ for 5-10 minutes and keep them warm.
[0033] S02: 3-5 parts of heat-insulated silicon carbide whiskers, 1-3 parts of nano-silica sol, 1-2 parts of stearic acid and 4-8 parts of sodium silicate solution are ball-milled at a speed of 750-850 r / min for 1-2 h. After ball milling, whisker slurry is obtained.
[0034] S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:7. Finally, filter and dry to obtain silicon carbide whisker agent.
[0035] The mass fraction of the potassium permanganate solution in this embodiment is 10-15%.
[0036] The sodium silicate solution in this embodiment has a mass fraction of 8-12%.
[0037] In this embodiment, the immersion pressure for the immersion treatment is 10~15MPa, and the immersion time is 20~30min.
[0038] The preparation method of the hydroxyapatite modifier in this embodiment is as follows:
[0039] S101: Heat-treat hydroxyapatite at 210~230℃ for 10~15min, then cool it to 55℃ at a rate of 2~4℃ / min and hold it at that temperature;
[0040] S102: 3-5 parts of heat-insulating hydroxyapatite, 2-4 parts of titanate coupling agent, 1-3 parts of glycolic acid and 6-10 parts of 15% sodium lignosulfonate solution are stirred together. After stirring, the mixture is washed with water and dried to obtain the hydroxyapatite modifier.
[0041] In this embodiment, the stirring speed is 450~500 r / min and the stirring time is 20~30 min.
[0042] The preparation method of a fly ash chelating agent in this embodiment includes the following steps: sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier raw materials to obtain the fly ash chelating agent.
[0043] Example 1.
[0044] A fly ash chelating agent according to this embodiment comprises the following raw materials in parts by weight:
[0045] 25 parts sodium dodecylbenzenesulfonate solution, 10 parts sodium sulfide, 5 parts dithiocarbamate, 3 parts lanthanum chloride solution, 2 parts silicon carbide whisker agent, and 1 part hydroxyapatite modifier.
[0046] In this embodiment, the sodium dodecylbenzenesulfonate solution has a mass fraction of 10%; the lanthanum chloride solution has a mass fraction of 2%.
[0047] The preparation method of the silicon carbide whisker agent in this embodiment is as follows:
[0048] S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry them. Then, preheat the dried silicon carbide whiskers at 55°C for 5 minutes and keep them warm.
[0049] S02: Three parts of heat-insulated silicon carbide whiskers, one part of nano-silica sol, one part of stearic acid and four parts of sodium silicate solution were ball-milled at a speed of 750 r / min for 1 h. After ball milling, whisker slurry was obtained.
[0050] S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:7. Finally, filter and dry to obtain silicon carbide whisker agent.
[0051] The potassium permanganate solution in this embodiment has a mass fraction of 10%.
[0052] The sodium silicate solution in this embodiment has a mass fraction of 8%.
[0053] In this embodiment, the immersion pressure for the immersion treatment is 10 MPa, and the immersion time is 20 min.
[0054] The preparation method of the hydroxyapatite modifier in this embodiment is as follows:
[0055] S101: Hydroxyapatite is heat-treated at 210℃ for 10 min, then cooled to 55℃ at a rate of 2℃ / min and held at that temperature.
[0056] S102: 3 parts of heat-insulating hydroxyapatite, 2 parts of titanate coupling agent, 1 part of glycolic acid and 6 parts of 15% sodium lignosulfonate solution were stirred together. After stirring, the mixture was washed with water and dried to obtain the hydroxyapatite modifier.
[0057] In this embodiment, the stirring speed is 450 r / min and the stirring time is 20 min.
[0058] The preparation method of a fly ash chelating agent in this embodiment includes the following steps: sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier raw materials to obtain the fly ash chelating agent.
[0059] Example 2.
[0060] A fly ash chelating agent according to this embodiment comprises the following raw materials in parts by weight:
[0061] 30 parts sodium dodecylbenzenesulfonate solution, 15 parts sodium sulfide, 10 parts dithiocarbamate, 6 parts lanthanum chloride solution, 4 parts silicon carbide whisker agent, and 3 parts hydroxyapatite modifier.
[0062] In this embodiment, the sodium dodecylbenzenesulfonate solution has a mass fraction of 15%; the lanthanum chloride solution has a mass fraction of 5%.
[0063] The preparation method of the silicon carbide whisker agent in this embodiment is as follows:
[0064] S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry them. Then, preheat the dried silicon carbide whiskers at 60°C for 10 minutes and keep them warm.
[0065] S02: 5 parts of heat-insulated silicon carbide whiskers, 3 parts of nano-silica sol, 2 parts of stearic acid and 8 parts of sodium silicate solution were ball-milled at 850 r / min for 2 h. After ball milling, whisker slurry was obtained.
[0066] S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:7. Finally, filter and dry to obtain silicon carbide whisker agent.
[0067] The potassium permanganate solution in this embodiment has a mass fraction of 15%.
[0068] The sodium silicate solution in this embodiment has a mass fraction of 12%.
[0069] In this embodiment, the immersion pressure for the immersion treatment is 15 MPa, and the immersion time is 30 min.
[0070] The preparation method of the hydroxyapatite modifier in this embodiment is as follows:
[0071] S101: Hydroxyapatite was heat-treated at 230℃ for 15 min, then cooled to 55℃ at a rate of 4℃ / min and held at that temperature.
[0072] S102: 5 parts of heat-insulating hydroxyapatite, 4 parts of titanate coupling agent, 3 parts of glycolic acid and 10 parts of 15% sodium lignosulfonate solution were stirred together. After stirring, the mixture was washed with water and dried to obtain the hydroxyapatite modifier.
[0073] In this embodiment, the stirring speed is 500 r / min and the stirring time is 30 min.
[0074] The preparation method of a fly ash chelating agent in this embodiment includes the following steps: sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier raw materials to obtain the fly ash chelating agent.
[0075] Example 3.
[0076] A fly ash chelating agent according to this embodiment comprises the following raw materials in parts by weight:
[0077] Sodium dodecylbenzenesulfonate solution 27.5 parts, sodium sulfide 12.5 parts, dithiocarbamate 7.5 parts, lanthanum chloride solution 4.5 parts, silicon carbide whisker agent 3 parts, hydroxyapatite modifier 2 parts.
[0078] In this embodiment, the sodium dodecylbenzenesulfonate solution has a mass fraction of 12.5%; the lanthanum chloride solution has a mass fraction of 3.5%.
[0079] The preparation method of the silicon carbide whisker agent in this embodiment is as follows:
[0080] S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry. Then, preheat the dried silicon carbide whiskers at 57°C for 5-10 minutes and keep them warm.
[0081] S02: 4 parts of heat-insulated silicon carbide whiskers, 2 parts of nano-silica sol, 1.5 parts of stearic acid and 6 parts of sodium silicate solution were ball-milled at 800 r / min for 1.5 h. After ball milling, whisker slurry was obtained.
[0082] S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:7. Finally, filter and dry to obtain silicon carbide whisker agent.
[0083] The mass fraction of the potassium permanganate solution in this embodiment is 12.5%.
[0084] The sodium silicate solution in this embodiment has a mass fraction of 10%.
[0085] In this embodiment, the immersion pressure for the immersion treatment is 12.5 MPa, and the immersion time is 25 min.
[0086] The preparation method of the hydroxyapatite modifier in this embodiment is as follows:
[0087] S101: Hydroxyapatite was heat-treated at 220℃ for 12 min, then cooled to 55℃ at a rate of 3℃ / min and held at that temperature.
[0088] S102: 4 parts of heat-insulating hydroxyapatite, 3 parts of titanate coupling agent, 2 parts of glycolic acid and 8 parts of 15% sodium lignosulfonate solution were stirred together. After stirring, the mixture was washed with water and dried to obtain the hydroxyapatite modifier.
[0089] In this embodiment, the stirring speed is 470 r / min and the stirring time is 25 min.
[0090] The preparation method of a fly ash chelating agent in this embodiment includes the following steps: sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier raw materials to obtain the fly ash chelating agent.
[0091] Comparative Example 1.
[0092] Unlike Example 3, no silicon carbide whisker agent was added.
[0093] Comparative Example 2.
[0094] Unlike Example 3, the preparation of the silicon carbide whisker agent did not involve the use of an impregnated glass fiber agent.
[0095] Comparative Example 3.
[0096] Unlike Example 3, the impregnated glass fiber agent is replaced with glass fiber.
[0097] Comparative Example 4.
[0098] Unlike Example 3, the whisker slurry in the preparation of silicon carbide whisker agent is made by mixing 4 parts silicon carbide whiskers and 6 parts deionized water.
[0099] Comparative Example 5.
[0100] Unlike Example 3, no hydroxyapatite modifier was added.
[0101] Comparative Example 6.
[0102] Unlike Example 3, the preparation of the hydroxyapatite modifier uses S102 treatment.
[0103] The performance of the products in Examples 1-3 and Comparative Examples 1-6 was tested, and the test results are as follows;
[0104] Examples 1-3 and Comparative Examples 1-6 were mixed with fly ash at a weight ratio of 5:2. The removal rates of chromium and zinc ions were tested. Simultaneously, under normal conditions, a hydrochloric acid solution at 2% of the total fly ash amount was added, and the mixture was placed at 5°C to test the removal rates of acid-resistant and low-temperature-resistant heavy metal ions. The performance tests are as follows:
[0105]
[0106] As can be seen from Comparative Examples 1-6 and Examples 1-3;
[0107] The product of this invention can achieve coordinated improvement in the removal rates of chromium ions and zinc ions, while the product also exhibits significant stability in the removal rate of heavy metal ions due to its resistance to acid corrosion and low temperatures.
[0108] The performance of the product shows a significant deterioration trend when neither silicon carbide whisker agent nor hydroxyapatite modifier is added in the preparation of the silicon carbide whisker agent. Furthermore, the performance of the product also deteriorates when glass fiber impregnation is not used in the preparation of the silicon carbide whisker agent, when glass fiber is used instead of impregnation glass fiber agent, when the whisker slurry is made by mixing 4 parts silicon carbide whiskers and 6 parts deionized water, and when S102 is used in the preparation of the hydroxyapatite modifier. Only the silicon carbide whisker agent and hydroxyapatite modifier prepared using the method of this invention exhibit the most significant synergistic effect, resulting in the most obvious performance improvement of the product.
[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0110] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A fly ash chelating agent, characterized in that, Including the following parts by weight of raw materials: Sodium dodecylbenzenesulfonate solution 25-30 parts, sodium sulfide 10-15 parts, dithiocarbamate 5-10 parts, lanthanum chloride solution 3-6 parts, silicon carbide whisker agent 2-4 parts, hydroxyapatite modifier 1-3 parts. The preparation method of the silicon carbide whisker agent is as follows: S01: First, stir and mix the silicon carbide whiskers in a sufficient amount of potassium permanganate solution, then wash with water and dry. Then, preheat the dried silicon carbide whiskers at 55~60℃ for 5-10 minutes and keep them warm. S02: 3-5 parts of heat-insulated silicon carbide whiskers, 1-3 parts of nano-silica sol, 1-2 parts of stearic acid and 4-8 parts of sodium silicate solution are ball-milled at a speed of 750-850 r / min for 1-2 h. After ball milling, whisker slurry is obtained. S03: Immerse glass fibers in a sufficient amount of 5% yttrium nitrate solution for immersion treatment. After immersion, filter and dry to obtain the immersed glass fiber agent. Mix the immersed glass fiber agent and whisker slurry at a weight ratio of 4:
7. Finally, filter and dry to obtain silicon carbide whisker agent. The preparation method of the hydroxyapatite modifier is as follows: S101: Heat-treat hydroxyapatite at 210~230℃ for 10~15min, then cool it to 55℃ at a rate of 2~4℃ / min and hold it at that temperature; S102: 3-5 parts of heat-insulating hydroxyapatite, 2-4 parts of titanate coupling agent, 1-3 parts of glycolic acid and 6-10 parts of 15% sodium lignosulfonate solution are stirred together. After stirring, the mixture is washed with water and dried to obtain the hydroxyapatite modifier.
2. The fly ash chelating agent according to claim 1, characterized in that, The fly ash chelating agent comprises the following raw materials in parts by weight: 27.5 parts sodium dodecylbenzenesulfonate solution, 12.5 parts sodium sulfide, 7.5 parts dithiocarbamate, 4.5 parts lanthanum chloride solution, 3 parts silicon carbide whisker agent, and 2 parts hydroxyapatite modifier.
3. The fly ash chelating agent according to claim 2, characterized in that, The sodium dodecylbenzenesulfonate solution has a mass fraction of 10-15%; the lanthanum chloride solution has a mass fraction of 2-5%.
4. The fly ash chelating agent according to claim 3, characterized in that, The potassium permanganate solution has a mass fraction of 10-15%.
5. The fly ash chelating agent according to claim 4, characterized in that, The sodium silicate solution has a mass fraction of 8-12%.
6. The fly ash chelating agent according to claim 5, characterized in that, The immersion pressure for the immersion treatment is 10~15MPa, and the immersion time is 20~30min.
7. A fly ash chelating agent according to claim 6, characterized in that, The stirring speed for the stirring process is 450~500 r / min, and the stirring time is 20~30 min.
8. A method for preparing the fly ash chelating agent as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The fly ash chelating agent is obtained by sequentially stirring and mixing sodium dodecylbenzenesulfonate solution, sodium sulfide, dithiocarbamate, lanthanum chloride solution, silicon carbide whisker agent, and hydroxyapatite modifier.