Method for preparing coagulant with high Al13 content from aluminum ash
PACl coagulant with high Al13 content was prepared from aluminum ash through steps such as ball milling, sieving, water washing, calcination, acid dissolution and polymerization, which solved the problems of aluminum ash accumulation and environmental pollution, and achieved efficient resource utilization and cost reduction.
Patent Information
- Application Number
- CN202510966545.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-14
- Publication Date
- 2025-10-17
AI Technical Summary
The problems of aluminum ash accumulation and environmental pollution have not been effectively solved in the current technology, and the production cost of traditional coagulants is high and resources are not fully utilized.
PACl coagulant with high Al13 content is prepared from aluminum ash through steps such as ball milling, sieving, water washing, calcination, acid dissolution and polymerization. This includes controlling parameters such as particle size, temperature and time to achieve efficient aluminum recovery and impurity removal.
The prepared coagulant has high purity, increased Al13 content, high resource utilization rate, reduced production costs, and solved the problems of aluminum ash accumulation and environmental pollution, thus having good market benefits.
Smart Images
Figure CN120793983A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of coagulant preparation, and particularly relates to a method for preparing a coagulant with high Al13 content by using aluminum ash. BACKGROUND
[0002] Aluminum ash is a solid material generated in the production, use and recycling of aluminum and other aluminum products. In China, the annual output of aluminum ash is expected to exceed 3 million tons. At present, the main disposal method of aluminum ash is stacking or landfill, which not only occupies a large amount of land resources, but also brings many environmental problems. In 2016, China officially included aluminum ash in the National Hazardous Waste List, and the National Hazardous Waste List implemented on January 1, 2021 expanded and refined the types of hazardous waste aluminum ash, and clearly included secondary aluminum ash in the management of hazardous waste, and included aluminum ash and secondary aluminum ash in the list of hazardous waste exemption management. As can be seen, the Chinese government attaches more and more importance to the treatment and disposal of aluminum ash.
[0003] In recent years, with the maturity and development of coagulant preparation technology, using aluminum ash as raw material for preparation is a more economical and reasonable comprehensive utilization way. Polyaluminum chloride (PACl) is the most mature technology and the largest market sales coagulant. At present, the main production method in China is to use bauxite or calcium aluminate to react with hydrochloric acid to produce, which consumes a large amount of mineral resources and has high production cost. Using aluminum ash as raw material to prepare PACl coagulant can not only effectively solve the accumulation of aluminum ash and the pollution problem caused to the environment, but also reduce the comprehensive cost of production, and has better economic benefits and competitive advantage in production practice due to similar product quality and simple process flow.
[0004] PACl coagulant will produce different polyaluminum forms in the hydrolysis process, among which Al13 ([AlO4Al 12 (OH) 24 (H2O) 12 ] 7+ ) has attracted widespread attention due to its efficient electric neutralization performance and special nano characteristics. Al13 has unique advantages compared with traditional PACl coagulant, and has stronger effect on the removal of turbidity, organic matter, anionic pollutants and new pollutants, and sludge conditioning. Therefore, using aluminum ash to prepare PACl coagulant with high Al13 content has good market benefits. SUMMARY
[0005] The purpose of the embodiment of the application is to provide a method for preparing a coagulant with high Al13 content by using aluminum ash, which aims to solve the technical problems existing in the prior art identified in the background.
[0006] The embodiment of the present application is implemented in a method for preparing a high-Al13-content coagulant from aluminum ash, comprising the following steps:
[0007] Powder preparation: taking aluminum ash for ball milling and screening to obtain aluminum ash powder;
[0008] Water washing: collecting the aluminum ash powder for hydrolysis reaction by water washing, and obtaining a hydrolysis filter cake through solid-liquid separation;
[0009] Calcination: drying and high-temperature calcination of the hydrolysis filter cake, and obtaining a solid powder after cooling;
[0010] Acid dissolution and polymerization: acid dissolution reaction of the solid powder with hydrochloric acid, followed by polymerization reaction with calcium aluminate, and obtaining an aluminum-containing acidic solution after solid-liquid separation;
[0011] Crystallization and separation: concentration crystallization of the aluminum-containing acidic solution, and obtaining a high-Al13-content PACl coagulant after solid-liquid separation.
[0012] As a further technical solution of the present application, the particle size of the aluminum ash powder is 45-72 μm.
[0013] By ball milling and screening treatment of the aluminum ash, the aluminum ash particles are mechanically ground to the optimal particle size of 45-72 μm for quality inspection, so that the surface layer of the aluminum ash particles can be removed, and the chemically active metal surface is exposed.
[0014] As a further technical solution of the present application, the temperature of the hydrolysis reaction is 80-100°C, and the reaction time is 24-72 h.
[0015] Through water washing, the AlN in the aluminum ash can be hydrolyzed, and the salts in the aluminum ash can be completely removed.
[0016] As a further technical solution of the present application, the high-temperature calcination temperature is 500-1000°C, and the calcination time is 1.5-3 h.
[0017] The calcination temperature and time need to be kept within a reasonable range. Too low calcination temperature or too short calcination time is not conducive to the subsequent step of aluminum dissolution, while too high calcination temperature or too long calcination time will cause unnecessary energy waste. The set calcination temperature and time in the present application can efficiently facilitate the dissolution of aluminum.
[0018] As a further technical solution of the present application, the acid dissolution reaction conditions include: the concentration of hydrochloric acid is 0.1-5 mol / L, the reaction temperature is 50-100°C, and the reaction time is 2-5 h.
[0019] As a further technical solution of the present application, during the polymerization reaction, the added calcium aluminate needs to make the basicity of the aluminum-containing acidic solution be 2.0-2.8.
[0020] The present application realizes efficient removal of nitrides and salts in aluminum ash and full recycling of aluminum in the aluminum ash, and prepares a coagulant product, thereby realizing resource utilization of solid waste. All reactions involved in the present application are carried out at normal pressure, the prepared coagulant has few impurities, high purity and high Al13 content, and has wide industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 A process flow chart of a method for preparing a coagulant with high Al13 content from aluminum ash is provided for the embodiments of the present application. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.
[0023] The specific implementation of the present application is described in detail below in combination with specific embodiments.
[0024] Embodiment 1
[0025] A coagulant 1 was prepared with the following parameters: water washing temperature 85℃, water washing time 24h, high-temperature calcination temperature 700℃, calcination time 2h, hydrochloric acid concentration 5mol / L, solid-liquid ratio 20ml / g, acid dissolution reaction time about 3h, calcium aluminate addition amount 0.02g / mL, and polymerization reaction 2h.
[0026] The traditional method for preparing polyaluminum chloride from aluminum ash mainly includes ball milling, screening, water washing, acid dissolution, polymerization and aging reaction. The coagulant 2 was prepared using the traditional method, and the specific experimental parameters are as follows: water washing temperature 80℃, high-temperature calcination temperature 700℃, calcination time 2h, hydrochloric acid concentration 5mol / L, solid-liquid ratio 20ml / g, acid dissolution reaction time about 2h, aging temperature 80℃, and aging time 42h.
[0027] The Al13 content was determined by Al-Ferron timed complexing colorimetry, and the Al13 content of the coagulant 1 was increased by about 39.85% compared with the coagulant 2.
[0028] Specifically, the Al-Ferron timed complexing colorimetry includes the following steps:
[0029] S1, preparation of Ferron reagent
[0030] Reagent A (0.2% m / v Ferron solution): Weigh 2.0 g of Ferron reagent, dissolve in 1020 mL of deionized water, heat the solution to boiling, magnetically stir for 24 h to dissolve the reagent, filter the filtrate through a 0.45 μm filter membrane, and store in a refrigerator at 4°C.
[0031] Reagent B (20% w / v sodium acetate solution): Weigh 200.0 g of sodium acetate, dissolve in an appropriate amount of deionized water, and dilute to 1 L.
[0032] Reagent C (1:9 v / v hydrochloric acid solution): Mix 100 mL of hydrochloric acid with 900 mL of deionized water.
[0033] Mix reagents A+B+C in a volume ratio of 2.5:2:1 to obtain the Ferron reagent. The mixing order is B+C, then A.
[0034] S2, preparation of standard curve
[0035] Take a certain volume of high-concentration mother liquor (obtained by diluting Al standard solution) and dilute to 25.0 mg Al / L. Take 0.5, 1.0, 1.5, 2.0, and 2.5 mL of the above diluted aluminum standard solution into 25 mL cuvettes, respectively. Add 5.5 mL of Ferron reagent to each, and dilute to the mark with pure water. Load the samples into 1 cm quartz cuvettes, use the diluted Ferron reagent (5.5 mL + deionized water 19.5 mL) as a blank, and use a UV spectrophotometer to measure the absorbance at 366 nm. According to the absorbance measurement values of the aluminum standard solution at each concentration gradient, fit the aluminum concentration-absorbance standard curve.
[0036] S3, Ferron colorimetric determination analysis process
[0037] Take 5.5 mL of Ferron reagent into a 25 mL cuvette and dilute to the mark. Start timing while adding 20 μL of the sample solution, shake the cuvette quickly, and load it into the cuvette. Perform time scanning of the absorbance at 366 nm within 30 s to 2 h after mixing. The absorbance at 60 s is contributed by Ala, and the absorbance change from 1 min to 2 h reflects the content of Alb. The content of Alc is calculated by subtracting the sum of the two forms from AlT.
[0038] Example 2
[0039] With the parameters of water washing temperature 80°C, water washing time 24 h, high-temperature calcination temperature 500°C, calcination time 1.5 h, hydrochloric acid concentration 5 mol / L, solid-liquid ratio 20 ml / g, acid dissolution reaction time about 2 h, calcium aluminate addition amount 0.02 g / mL, and polymerization reaction 2 h, the coagulant 3 is prepared.
[0040] Using the traditional method in Example 1, polyaluminum chloride was prepared with aluminum ash as raw material to obtain coagulant 4, and the specific experimental parameters were as follows: water washing at 80℃, drying temperature at 80℃, hydrochloric acid concentration at 5mol / L, solid-liquid ratio at 20ml / g, acid dissolution reaction time at about 2h, aging temperature at 80℃, and aging time at 42h.
[0041] The Al13 content was determined by Al-Ferron complexing colorimetry, and the Al13 content in coagulant 3 was increased by about 32.96% compared with that in coagulant 4.
[0042] Example 3
[0043] Coagulant 5 was prepared with the parameters of water washing temperature at 100℃, water washing time at 72h, high-temperature calcination temperature at 1000℃, calcination time at 3h, hydrochloric acid concentration at 5mol / L, solid-liquid ratio at 20ml / g, acid dissolution reaction time at about 5h, calcium aluminate addition amount at 0.02g / mL, and polymerization reaction time at 2h.
[0044] Using the traditional method in Example 1, polyaluminum chloride was prepared with aluminum ash as raw material to obtain coagulant 6, and the specific experimental parameters were as follows: water washing at 80℃, high-temperature calcination at 700℃, calcination time at 2h, hydrochloric acid concentration at 5mol / L, solid-liquid ratio at 20ml / g, acid dissolution reaction time at about 2h, aging temperature at 80℃, and aging time at 42h.
[0045] The Al13 content was determined by Al-Ferron complexing colorimetry, and the Al13 content in coagulant 3 was increased by about 37.53% compared with that in coagulant 4.
[0046] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for preparing a high Al13 content coagulant using aluminum ash, characterized in that: The method comprises the following steps: Powder preparation: aluminum ash is ball-milled and sieved to obtain aluminum ash powder; Water washing: collect the aluminum ash powder, wash it with water, perform hydrolysis reaction, and separate the solid and liquid to obtain the hydrolysis filter cake; Calcination: drying and calcining the hydrolysis filter cake at high temperature, and obtaining solid powder after cooling; Acid dissolution and polymerization: solid powder is subjected to acid dissolution reaction with hydrochloric acid, calcium aluminate is then added for polymerization reaction, and an aluminum-containing acidic solution is obtained after solid-liquid separation; Crystallization separation: The aluminum-containing acidic solution is concentrated and crystallized, and a high Al13 content PACl coagulant is obtained after solid-liquid separation.
2. The method for preparing a high Al13 content coagulant using aluminum ash according to claim 1, characterized in that: The particle size of the aluminum ash powder is 45-72 μm.
3. The method for preparing a high Al13 content coagulant using aluminum ash according to claim 1, wherein: The temperature of the hydrolysis reaction is 80-100° C., and the reaction time is 24-72 hours.
4. The method for preparing a high Al13 content coagulant using aluminum ash according to claim 1, characterized in that: The high temperature calcination temperature is 500-1000° C., and the calcination time is 1.5-3 hours.
5. The method for preparing a high Al13 content coagulant using aluminum ash according to claim 1, characterized in that: The acid dissolution reaction conditions include: hydrochloric acid concentration of 0.1-5 mol / L, reaction temperature of 50-100° C., and reaction time of 2-5 h.
6. The method for preparing a high Al13 content coagulant using aluminum ash according to claim 5, characterized in that: During the polymerization reaction, the added calcium aluminate needs to make the alkalinity of the aluminum-containing acidic solution 2.0-2.8.