Method for preparing polyaluminum chloride water purifying agent from aluminum ash
By pretreating and modifying the aluminum ash, combined with the sol-gel conversion method, a high-activity and high-stability polymer aluminum chloride water purification agent was prepared, which solved the insufficient resource utilization of aluminum ash and the poor water purification effect. The problem of stability achieves efficient and stable water purification effect.
Patent Information
- Application Number
- CN202411609708.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-02-11
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the prior art, the resource utilization of aluminum ash and the unstable water purification effect have resulted in the preparation conditions of polymer aluminum chloride water purification agents, high energy consumption, and easy product impurities to exceed the standard.
The recycled aluminum ash is pretreated, including sieving, magnetic separation, air separation and water washing, to remove impurities and improve purity. Then, the aluminum hydroxide solid was modified, and the sodium hydroxide solution was added and heated to form an activated aluminum hydroxide gel. Finally, through the sol-gel conversion method, the activated aluminum hydroxide gel is mixed with polymer aluminum chloride to form a highly active and high-stability polymer aluminum chloride water purifier.
The water purification effect and stability of the polymer aluminum chloride water purifier is improved, the resource utilization of aluminum ash is realized, and the pollution to the environment is reduced.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nonferrous metallurgy environmental protection, and specifically relates to a method for preparing a polyaluminium chloride water purifier by using aluminium ash. Background Art
[0002] Poly Aluminum Chloride (PAC) is a polyhydroxyl, polynuclear complex cationic inorganic polymer flocculant. Its general chemical formula can be expressed as Al2(OH) n Cl 6−n _{m}, where n and m represent the number of hydroxyl and chloride ions, which may vary with the production process and raw material ratio. Polyaluminium chloride is a water-soluble inorganic high molecular polymer between aluminium chloride and aluminium hydroxide. It usually appears as a yellow or light yellow, dark brown or dark grey resinous solid. It has the advantages of wide adaptability to water areas, fast hydrolysis rate, strong adsorption capacity, large alum flocs, fast dense precipitation, low effluent turbidity and good dehydration performance. It has the characteristics of fine powder, uniform particles, easy solubility in water, good flocculation effect, efficient and stable purification, small dosage and low cost, making it a commonly used coagulant in water treatment.
[0003] Aluminum ash is a waste product in the aluminum processing process, which contains various components such as metallic aluminum, aluminum nitride, and aluminum oxide. There have been studies on using aluminum ash as a raw material for preparing water purifiers. In the prior art, the processing process of aluminum ash mainly includes adding water to dissolve water-soluble substances, heating and hydrolyzing aluminum nitride to generate aluminum hydroxide and ammonia, and adding hydrochloric acid to dissolve unhydrolyzed metallic aluminum, newly generated aluminum hydroxide and part of highly active aluminum oxide.
[0004] The market demand for PAC accounts for the vast majority of the total demand for coagulants, and its demand is still increasing year by year, with huge market demand potential. However, in the traditional industrial preparation process of PAC, there are shortcomings such as harsh preparation conditions, high energy consumption, and easy excess of product impurities. Therefore, improving the preparation method of PAC or developing a new preparation method will be used to solve the technical problems of insufficient resource utilization of aluminum ash and unstable water purification effect in the existing technology. Summary of the invention
[0005] The purpose of the present invention is to provide a method for preparing a polyaluminium chloride water purifier by using aluminium ash, so as to solve the technical problems of insufficient resource utilization of aluminium ash and unstable water purification effect in the prior art.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and stirred to obtain an active aluminum hydroxide gel; (3) Through the sol-gel conversion method, the active aluminum hydroxide gel and the polyaluminum chloride water purifier are mixed, heated and stirred, and the polyaluminum chloride water purifier is obtained after the active aluminum hydroxide gel is completely dissolved.
[0007] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is first put into a vibrating screen for screening and sorting, and then sequentially subjected to magnetic separation, air separation and water washing, and further placed in an oven for drying to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Add the aluminum ash to be reacted into the reactor, add deionized water, heat and stir. After the reaction is completed, put it into an oven to dry to obtain aluminum hydroxide solid.
[0008] Furthermore, the mesh of the vibrating screen in S1 is 2-500 mesh, the temperature of the oven is 65-80°C, and the drying time is 28-32h; the liquid-to-aluminum ash and water ratio in S2 is 1:8-10, heated to 70-80°C, the stirring speed is 200-300rpm, the reaction time is 2-3h, the temperature of the oven is 70-80°C, and the drying time is 24-30h.
[0009] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: adding a surfactant to aluminum hydroxide solid, stirring and heating, and obtaining modified aluminum hydroxide after the reaction is completed; Q2. Preparation of sodium aluminate solution: drying and grinding the modified aluminum hydroxide, adding it to the sodium hydroxide solution in stages, adding a catalyst, and using ultrasound to assist the reaction, heating, and obtaining a sodium aluminate solution after the reaction is completed; Q3. Add acid and stir: Slowly add hydrochloric acid solution to the sodium aluminate solution, heat and stir rapidly to obtain active aluminum hydroxide gel.
[0010] Furthermore, the surfactant in Q1 is a mixture of sodium dodecyl sulfate and hexadecyltrimethylammonium bromide, the mass ratio of sodium dodecyl sulfate to hexadecyltrimethylammonium bromide is 1:(2-3), the surfactant accounts for 0.5-1wt% of aluminum hydroxide, heated to 50-60°C, and reacted for 1-2h; the mass ratio of modified aluminum hydroxide to sodium hydroxide solution in Q2 is 1:3, the concentration of sodium hydroxide solution is 1-2M, the modified aluminum hydroxide is gradually added in 3-4 equal parts, and the catalyst is chlorine A mixture of calcium chloride and zinc chloride, the mass ratio of calcium chloride to zinc chloride is 1:1, the amount of catalyst added is 0.5-1% of the mass of modified aluminum hydroxide, the ultrasonic frequency is set to 20-30kHz, the stirring speed is 400-600rpm, heated to 100-105℃, and the reaction time is 2-3h; the volume ratio of hydrochloric acid solution to sodium aluminate solution in Q3 is 1:1, the concentration of hydrochloric acid solution is 1-2M, the stirring speed is 450-550rpm, and heated to 50-60℃.
[0011] Furthermore, in the sol-gel conversion method in step (3), the volume ratio of mixed active aluminum hydroxide and polyaluminum chloride is 1:2-5, heated to 50-80°C, the pH is 3-5, the stirring speed is 400-600rpm, and the dissolution time is 1-2h.
[0012] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention removes impurities and non-aluminum components in aluminum ash by screening, magnetic separation, air separation and water washing, ensures the purity and reaction efficiency of subsequent reactions, and modifies aluminum hydroxide to enhance its reaction activity. Further, by sol-gel conversion method, it is ensured that the active aluminum hydroxide gel is completely dissolved in polyaluminum chloride to form a uniform suspension, and finally obtains a highly active and highly stable polyaluminum chloride water purifier, thereby improving the water purification effect and stability of the water purifier. The present invention uses aluminum ash to prepare a highly active and highly stable polyaluminum chloride water purifier, realizes the resource utilization of waste, and reduces the pollution of aluminum ash to the environment.
[0013] 2. The present invention enhances the reactivity of aluminum hydroxide by adding a surfactant, improves its solubility and reaction efficiency in subsequent reactions, enhances the reactivity of aluminum hydroxide and sodium hydroxide solution, further utilizes the cavitation effect of ultrasound to accelerate the contact and reaction between reactants, improves the reaction rate and product purity, shortens the reaction time, and improves the reaction efficiency. In addition, by controlling the concentration and addition rate of hydrochloric acid, the generation of highly active aluminum hydroxide gel is ensured, while avoiding side reactions caused by excessive local concentration, optimizing the uniformity and activity of the gel, and obtaining a polyaluminum chloride water purifier of better quality. DETAILED DESCRIPTION
[0014] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0015] Embodiment 1: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) Through the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 2 L of existing polyaluminum chloride water purifier are mixed, heated to 50°C, and stirred at a speed of 400 rpm. After the active aluminum hydroxide gel is completely dissolved, the polyaluminum chloride water purifier is obtained.
[0016] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 50-mesh vibrating screen, and then sequentially subjected to magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 65° C. for a drying time of 28 h to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 8-10 L of deionized water, heat to 70°C, stir at 200 rpm, react for 2 hours, put into an oven to dry, the oven temperature is 70°C, the drying time is 24 hours, and aluminum hydroxide solid is obtained.
[0017] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 4 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat, heat to 50°C, react for 1 hour, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it into 3 L of 1 M sodium hydroxide solution in 3 times, then add 2.5 g of calcium chloride and 2.5 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 20 kHz, the stirring speed is 400 rpm, and the mixture is heated to 100 ° C and reacted for 2 h to obtain a sodium aluminate solution; Q3. Add acid and stir: Slowly add 1L of 1M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 50°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0018] Embodiment 2: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) By the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 2.5 L of existing polyaluminum chloride water purifier were mixed, heated to 55°C, and stirred at a speed of 430 rpm. After the active aluminum hydroxide gel was completely dissolved, the polyaluminum chloride water purifier was obtained.
[0019] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 100-mesh vibrating screen, and then sequentially subjected to magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 70° C. for a drying time of 29 hours to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 8-10 L of deionized water, heat to 72°C, stir at 220 rpm, react for 2.5 hours, put into the oven to dry, the oven temperature is 72°C, the drying time is 25 hours, and aluminum hydroxide solid is obtained.
[0020] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 5 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat to 52°C, react for 1-2 hours, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it into 3 L of 1.2 M sodium hydroxide solution in 4 times, then add 2.5 g of calcium chloride and 2.5 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 23 kHz, the stirring speed is 450 rpm, and the reaction is heated to 100 ° C. for 2 hours to obtain a sodium aluminate solution; Q3. Add acid and stir: Slowly add 1L of 1.2M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 55°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0021] Embodiment 3: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) Through the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 3 L of existing polyaluminum chloride water purifier were mixed, heated to 60°C, and stirred at a speed of 500 rpm. After the active aluminum hydroxide gel was completely dissolved, the polyaluminum chloride water purifier was obtained.
[0022] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 250-mesh vibrating screen, and then sequentially through magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 69° C. for 30 hours to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 9 L of deionized water, heat to 74°C, stir at 220 rpm, react for 2 hours, put into the oven to dry, the oven temperature is 74°C, the drying time is 25 hours, and aluminum hydroxide solid is obtained.
[0023] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 5 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat, heat to 60°C, react for 2 hours, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it into 3 L of 1.4 M sodium hydroxide solution in 4 times, then add 2.5 g of calcium chloride and 2.5 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 26 kHz, the stirring speed is 480 rpm, and the mixture is heated to 102 ° C and reacted for 2 h to obtain a sodium aluminate solution. Q3. Add acid and stir: Slowly add 1L of 1.4M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 56°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0024] Embodiment 4: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) Through the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 4 L of existing polyaluminum chloride water purifier were mixed, heated to 70°C, and stirred at a speed of 500 rpm. After the active aluminum hydroxide gel was completely dissolved, the polyaluminum chloride water purifier was obtained.
[0025] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 350-mesh vibrating screen, and then sequentially through magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 70° C. for 30 hours to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 8.5 L of deionized water, heat to 76°C, stir at 270 rpm, react for 2.5 hours, put into the oven to dry, the oven temperature is 76°C, the drying time is 27 hours, and aluminum hydroxide solid is obtained.
[0026] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 4-6 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat to 50-60° C., react for 1-2 hours, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it into 3 L of 1.7 M sodium hydroxide solution in 3 times, then add 3 g of calcium chloride and 3 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 28 kHz, the stirring speed is 550 rpm, heat to 13 ° C, react for 2.5 hours, and obtain a sodium aluminate solution; Q3. Add acid and stir: Slowly add 1L of 1.7M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 55°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0027] Embodiment 5: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) By the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 4 L of existing polyaluminum chloride water purifier were mixed, heated to 75°C, and stirred at a speed of 550 rpm. After the active aluminum hydroxide gel was completely dissolved, the polyaluminum chloride water purifier was obtained.
[0028] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 400-mesh vibrating screen, and then sequentially subjected to magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 75° C. for 30 hours to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 9 L of deionized water, heat to 75°C, stir at 280 rpm, react for 2.5 hours, put into the oven to dry, the oven temperature is 78°C, the drying time is 28 hours, and aluminum hydroxide solid is obtained.
[0029] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 5 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat to 58°C, react for 1.5 hours, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it to 3 L of 1.8 M sodium hydroxide solution in 3-4 portions, then add 4 g of calcium chloride and 4 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 28 kHz, the stirring speed is 580 rpm, and the mixture is heated to 104 ° C and reacted for 2.5 h to obtain a sodium aluminate solution. Q3. Add acid and stir: Slowly add 1L of 1.8M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 58°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0030] Embodiment 6: A method for preparing a polyaluminium chloride water purifier using aluminium ash comprises the following steps: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and rapidly stirred to obtain an active aluminum hydroxide gel; (3) Through the sol-gel conversion method, 1 L of active aluminum hydroxide gel and 5 L of existing polyaluminum chloride water purifier were mixed, heated to 80°C, and stirred at a speed of 600 rpm. After the active aluminum hydroxide gel was completely dissolved, the polyaluminum chloride water purifier was obtained.
[0031] The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is sorted through a 500-mesh vibrating screen, and then sequentially subjected to magnetic separation, air separation and water washing, and further placed in an oven for drying at a temperature of 80° C. for a drying time of 32 hours to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Take 1 kg of aluminum ash to be reacted and add it into the reactor, add 10 L of deionized water, heat to 80°C, stir at 300 rpm, react for 3 hours, put into an oven to dry, the oven temperature is 80°C, the drying time is 30 hours, and aluminum hydroxide solid is obtained.
[0032] The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: Add 2 g of sodium dodecyl sulfate and 6 g of hexadecyltrimethylammonium bromide to 1 kg of aluminum hydroxide solid, stir and heat, heat to 60°C, react for 2 hours, and obtain modified aluminum hydroxide; Q2. Preparation of sodium aluminate solution: Dry and grind 1 kg of modified aluminum hydroxide, add it into 3 L of 2 M sodium hydroxide solution in 4 times, then add 5 g of calcium chloride and 5 g of zinc chloride, and use ultrasound to assist the reaction. The ultrasonic frequency is set to 30 kHz, the stirring speed is 600 rpm, and the reaction is heated to 105 ° C. for 3 hours to obtain a sodium aluminate solution; Q3. Add acid and stir: Slowly add 1L of 2M hydrochloric acid solution to 1L of sodium aluminate solution, heat to 60°C, and stir rapidly to obtain active aluminum hydroxide gel.
[0033] Comparative Example 1: Compared with Example 6, in Comparative Example 1, during the preparation of the polyaluminium chloride water purifier, no aluminium hydroxide modification was performed, and other conditions remained unchanged.
[0034] Comparative Example 2: Compared with Example 6, in Comparative Example 2, during the preparation of polyaluminium chloride water purifier, no aluminium ash pretreatment was performed, and other conditions remained unchanged.
[0035] Comparative Example 3: Compared with Example 6, in Comparative Example 3, during the preparation of the polyaluminium chloride water purifier, when preparing the sodium aluminate solution, the modified aluminium hydroxide is not added in stages, and other conditions remain unchanged.
[0036] Experimental example: The following performance tests were performed on the polyaluminium chloride water purifiers prepared in Examples 1-6 and Comparative Examples 1-3: 1. Turbidity removal effect test According to the "Water and Wastewater Monitoring and Analysis Method", 9 groups of 1L simulated sewage were taken, and the initial turbidity (T0) was recorded respectively. The polyaluminium chloride water purifier prepared in Examples 1-6 and Comparative Examples 1-3 was dissolved in water at a ratio of 1:3 and then diluted with 20 times of clean water and added to the water samples respectively, stirred evenly, and stirred with a six-joint stirrer, first at 250rpm for 10min, then slowly stirred at 50rpm for 15min, and then allowed to settle for 30min. The supernatant was taken to measure the turbidity (T1), and the turbidity reduction rate was calculated according to Formula 1: Formula 1: 2. Chroma removal effect test According to the "Water and Wastewater Monitoring and Analysis Method", 9 groups of 1L simulated sewage were taken, and the initial turbidity (C0) was recorded respectively. The polyaluminium chloride water purifier prepared in Examples 1-6 and Comparative Examples 1-3 was dissolved in water at a ratio of 1:3 and then diluted with 20 times of clean water and added to the water samples respectively, stirred evenly, and stirred with a six-joint stirrer, first at 250rpm for 10min, then slowly stirred at 50rpm for 15min, and then allowed to settle for 30min. The supernatant was taken to measure the chromaticity (C1), and the chromaticity removal rate was calculated according to Formula 2: Formula 2: According to the above experimental method, the following experimental results are obtained, as shown in Table 1: Table 1 According to the test results in Table 1, the turbidity reduction rate and chromaticity removal rate of the polyaluminium chloride water purifier of Examples 1-6 of the present invention are significantly improved. By comparing Example 6 with Comparative Examples 1-3, it can be seen that in the process of preparing the polyaluminium chloride water purifier, modifying aluminum hydroxide, pre-treating aluminum ash, and adding aluminum hydroxide in stages can significantly improve the water purification effect of the polyaluminium chloride water purifier.
[0037] 3. Stability Test According to GB / T 6920-2008 "Polyaluminum Chloride as Water Treatment Agent", the polyaluminum chloride water purifier prepared in Examples 1-6 and Comparative Examples 1-3 was dissolved in water at a ratio of 1:3 to form a liquid, and then 20 times of clean water was added and divided into multiple transparent glass bottles, each with 50 mL. The bottles were placed at room temperature for 1 week, 2 weeks, 1 month and 3 months, respectively, and the changes in the appearance of the solution were observed and recorded to see if there was precipitation or stratification. The observation results are shown in Table 2: Table 2 According to the test results in Table 1, the stability of the polyaluminium chloride water purifiers of Examples 1-6 of the present invention is significantly improved. By comparing Example 6 with Comparative Examples 1-3, it can be seen that in the process of preparing the polyaluminium chloride water purifier, modifying the aluminium hydroxide, pre-treating the aluminium ash and adding the aluminium hydroxide in stages can significantly improve the stability of the polyaluminium chloride water purifier.
[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
[0039] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for preparing polyaluminium chloride water purifier using aluminium ash, characterized in that: The steps include: (1) Pre-treating the recovered aluminum ash to obtain aluminum ash to be reacted, adding the aluminum ash to a reactor, adding water to dissolve the water-soluble substances in the aluminum ash, and heating to obtain aluminum hydroxide solid; (2) After the aluminum hydroxide solid is modified, the modified aluminum hydroxide is obtained, which is added to a sodium hydroxide solution, heated, and fully reacted to obtain a sodium aluminate solution, to which a hydrochloric acid solution is added, and stirred to obtain an active aluminum hydroxide gel; (3) By a sol-gel conversion method, active aluminum hydroxide gel and polyaluminum chloride water purifier are mixed, heated and stirred, and after the active aluminum hydroxide gel is completely dissolved, polyaluminum chloride water purifier is obtained.
2. The method for preparing polyaluminium chloride water purifier by using aluminium ash according to claim 1, characterized in that: The preparation method of aluminum hydroxide solid comprises the following steps: S1. Aluminum ash pretreatment: The recovered aluminum ash is first put into a vibrating screen for screening and sorting, and then sequentially subjected to magnetic separation, air separation and water washing, and then put into an oven for drying to obtain aluminum ash to be reacted; S2. Dissolution of aluminum ash: Add the aluminum ash to be reacted into the reactor, add deionized water, heat and stir. After the reaction is completed, put it into an oven to dry to obtain aluminum hydroxide solid.
3. The method for preparing polyaluminium chloride water purifier by using aluminium ash according to claim 2, characterized in that: The mesh of the vibrating screen in S1 is 2-500 mesh, the temperature of the oven is 65-80°C, and the drying time is 28-32h.
4. The method for preparing polyaluminium chloride water purifier by using aluminium ash according to claim 2, characterized in that: The liquid-to-solid ratio of aluminum ash to water in S2 is 1:8-10, heated to 70-80°C, stirred at 200-300rpm, reacted for 2-3h, and dried in an oven at 70-80°C for 24-30h.
5. The method for preparing polyaluminium chloride water purifier by using aluminium ash according to claim 1, characterized in that: The preparation of active aluminum hydroxide gel comprises the following steps: Q1. Preparation of modified aluminum hydroxide: adding a surfactant to aluminum hydroxide solid, stirring and heating, and obtaining modified aluminum hydroxide after the reaction is completed; Q2. Preparation of sodium aluminate solution: drying and grinding the modified aluminum hydroxide, adding it to the sodium hydroxide solution in stages, adding a catalyst, and using ultrasound to assist the reaction, heating, and obtaining a sodium aluminate solution after the reaction is completed; Q3. Add acid and stir: Slowly add hydrochloric acid solution to the sodium aluminate solution, heat and stir rapidly to obtain active aluminum hydroxide gel.
6. The method for preparing polyaluminium chloride water purifier using aluminium ash according to claim 5, characterized in that: The surfactant in Q1 is a mixture of sodium dodecyl sulfate and hexadecyltrimethylammonium bromide, the mass ratio of sodium dodecyl sulfate to hexadecyltrimethylammonium bromide is 1:(2-3), the surfactant accounts for 0.5-1wt% of aluminum hydroxide, heated to 50-60°C, and reacted for 1-2h.
7. The method for preparing polyaluminium chloride water purifier using aluminium ash according to claim 5, characterized in that: The mass ratio of modified aluminum hydroxide to sodium hydroxide solution in Q2 is 1:3, the concentration of sodium hydroxide solution is 1-2M, the modified aluminum hydroxide is gradually added in 3-4 equal parts, the catalyst is a mixture of calcium chloride and zinc chloride, the mass ratio of calcium chloride to zinc chloride is 1:1, the amount of catalyst added is 0.5-1% of the mass of the modified aluminum hydroxide, the ultrasonic frequency is set to 20-30kHz, the stirring speed is 400-600rpm, the temperature is heated to 100-105°C, and the reaction time is 2-3h.
8. The method for preparing polyaluminium chloride water purifier using aluminium ash according to claim 5, characterized in that: The volume ratio of the hydrochloric acid solution to the sodium aluminate solution in Q3 is 1:1, the concentration of the hydrochloric acid solution is 1-2M, the stirring speed is 450-550rpm, and the mixture is heated to 50-60°C.
9. The method for preparing polyaluminium chloride water purifier using aluminium ash according to claim 1, characterized in that: In the sol-gel conversion method in step (3), the volume ratio of mixed active aluminum hydroxide and polyaluminum chloride is 1:2-5, heated to 50-80°C, the pH is 3-5, the stirring speed is 400-600rpm, and the dissolution time is 1-2h.