Calcium-aluminum composite emulsion, and preparation method and application thereof

Abstract

The application discloses a calcium-aluminum composite emulsion and a preparation method and application thereof, and belongs to the technical field of industrial solid waste treatment and environmental protection. The calcium-aluminum composite emulsion is mainly prepared from composite powders of aluminum oxide and calcium oxide, has a fast precipitation rate and good precipitation effect. The preparation method comprises the following steps: ball milling the aluminum oxide and the calcium oxide, adding non-ionic polyoxyethylene amide and non-ionic polyacrylamide, stirring, and adding ethylene glycol drop by drop in the stirring process to prepare the calcium-aluminum composite emulsion. The effective calcium content, the permeability and the precipitation performance of the calcium-aluminum composite emulsion are improved by using the aluminum oxide and the subsequent ball milling treatment, so that the calcium-aluminum composite emulsion can quickly and effectively precipitate phosphorus and fluorine pollutants in phosphorus-fluorine wastewater and phosphogypsum, the treated phosphogypsum meets the first-class solid waste, and the treated phosphorus-fluorine wastewater also meets the national standard. The application solves the technical problem that traditional lime reagents cannot simultaneously and efficiently remove phosphorus and fluorine due to low effective calcium content and poor permeability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial solid waste treatment and environmental protection, and particularly relates to a calcium-aluminum composite emulsion as well as a preparation method and application thereof. BACKGROUND

[0002] Phosphogypsum and phosphorus chemical wastewater generated by the phosphoric acid industry will have a serious impact on the environment, and it is very urgent to solve the harm of pollutants to the environment.

[0003] The traditional solution to this problem is to use lime neutralization and solidification method to treat phosphogypsum and phosphorus chemical wastewater. Lime neutralization is an effective treatment method, which can solidify the harmful components in phosphogypsum and convert them into a kind of solid waste. This method has the advantages of simple process route, low investment, etc., and is particularly suitable for phosphogypsum with low organic matter content and stable quality.

[0004] However, the traditional lime agent has the problems of low effective calcium content and poor permeability, for example, first, the effective calcium content of the traditional lime agent is usually low, which leads to the need for a large amount of lime to be added to achieve the expected treatment effect when treating phosphogypsum and phosphorus chemical wastewater, which not only increases the treatment cost, but also may introduce new pollution problems due to excessive addition; second, the dispersibility and permeability of lime particles in wastewater are poor, which leads to insufficient contact between them and the pollutants in the wastewater, resulting in low reaction efficiency. This will affect the treatment effect, making it difficult to completely remove phosphorus and fluorine in the wastewater; at the same time, the traditional lime neutralization method is difficult to achieve the standards of soluble phosphorus, soluble fluorine and pH value after treating phosphorus chemical waste, which leads to the risk of environmental pollution of the treated waste, and cannot meet the increasingly stringent environmental protection regulations. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a calcium-aluminum composite emulsion as well as a preparation method and application thereof, to solve the technical problem that the traditional lime agent cannot simultaneously and efficiently remove phosphorus and fluorine due to low effective calcium content and poor permeability.

[0006] In order to achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0007] The present application discloses a calcium-aluminum composite emulsion, which comprises: a composite powder prepared by ball milling calcium oxide and aluminum oxide powder, a first stirring after adding a surfactant, and a slow-release agent added drop by drop during stirring, standing for 2h, adding water to the reaction system for second stirring, and naturally cooling to room temperature to obtain the calcium-aluminum composite emulsion.

[0008] Preferably, the composite powder of calcium oxide and aluminum oxide powder has an effective content of calcium and aluminum both ≥80%.

[0009] Preferably, the mass ratio of calcium oxide and aluminum oxide powder is (14-15):(5-6).

[0010] Preferably, the ball milling adopts dry milling, the ball milling beads are agate beads with a diameter of 10 mm, the rotation speed is set to 250 rpm, the ball milling time is 2-3 h, and the particle size of 85% of the calcium oxide and aluminum oxide is less than 200 mesh.

[0011] Preferably, the surfactant is a non-ionic polyoxyethylene amide and a non-ionic polyacrylamide (PAM), and the mass ratio of the two is (1-2):(2-3).

[0012] Preferably, the mass ratio of the composite powder to the non-ionic polyoxyethylene amide and the non-ionic polyacrylamide (PAM) is 200:(1-2):(2-3).

[0013] More preferably, the polyoxyethylene amide non-ionic surfactant and the non-ionic PAM are commercially available products, and the molecular weight of the PAM is 5 million.

[0014] Preferably, the sustained-release agent includes one of ethylene glycol, methanol, glycerol or butanol, and the addition amount is 3-5 ml of the sustained-release agent per 100 g of calcium oxide and aluminum oxide powder.

[0015] More preferably, the sustained-release agent is used to control the hydration process of the composite powder, and a commercially available product with a purity of 99% is used.

[0016] Preferably, the calcium oxide and aluminum oxide are commercially available products with an effective calcium and aluminum content of ≥80%.

[0017] Preferably, 100 ml of water is added per 10 g of the composite powder.

[0018] Preferably, the first stirring time is controlled to be 5-10 min to allow the composite powder to fully contact with the surfactant, and the second stirring time is at least 2-3 h to reduce the reaction system temperature to room temperature. If the stirring time is too short, the composite powder cannot be completely emulsified, and if the stirring time is too long, the composite powder will react with carbon dioxide in the air to generate other insoluble substances, thereby reducing the effective content.

[0019] The application discloses a calcium-aluminum composite emulsion prepared by the above method.

[0020] The application also discloses application of the calcium-aluminum composite emulsion to harmless treatment of phosphogypsum, for the phosphogypsum with soluble phosphorus of 20-1000 mg / L and soluble fluorine of 10-7000 mg / kg, the composite emulsion with effective calcium and aluminum content accounting for a certain proportion of the dry mass of the phosphogypsum is added, after solidification reaction for 12-24 hours, the soluble phosphorus in the phosphogypsum is lower than 0.5 ppm, the soluble fluorine is lower than 10 ppm, and the pH value is maintained at 8-10, meeting the first-class solid waste; after the treated phosphogypsum is exposed to air and stacked for one month, the removal rates of the soluble phosphorus and the soluble fluorine are maintained at 99.3% and 98.4% respectively, and the concentrations are lower than the national standards.

[0021] The application also discloses application of the calcium-aluminum composite emulsion to treatment of phosphorus-fluorine wastewater, for the phosphorus-fluorine wastewater with phosphate concentration of 10-1000 mg / L, fluorine ion concentration of 10-450 mg / L and pH value lower than 4, after the wastewater is added to the composite emulsion with pH value of 10-11 and reacts for 2-5 minutes, the phosphate concentration is lower than 0.5 mg / L, and the fluorine ion concentration is lower than 10 mg / L.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] The preparation method of the calcium-aluminum composite emulsion disclosed in the application breaks through the technical defects of traditional lime reagent. First, the calcium-aluminum composite emulsion is prepared by using the composite powder formed by calcium oxide and aluminum oxide as raw material. The calcium-aluminum composite composition has strong affinity to fluoride ions and phosphate ions, can deeply remove these pollutants, and reduce the content in wastewater to a very low level, so that the treatment process is more efficient. In addition, the use of aluminum oxide powder improves the precipitation performance of the composite emulsion, and can improve the precipitation performance of the generated product when treating phosphorus chemical waste, so that the treatment effect can be stabilized. On the other hand, aluminum oxide is an amphoteric compound, and the use of aluminum oxide powder can control the mutation of the pH value of the reaction system caused by the excessive amount of the added amount in the treatment process, so that the three indicators of soluble phosphorus, soluble fluorine and pH value after the treatment of phosphorus chemical waste meet the national emission standards and the requirements of resource recovery, thereby solving the environmental problems generated in the production process of phosphorus chemical industry. Secondly, the milled calcium oxide and aluminum oxide powder is mixed with different types of slow-release agents and surfactants to improve the emulsification degree of the composite powder. Among them, the milled composite powder is subjected to high-speed friction and collision with spherical abrasive in a ball mill. This mechanical action can break the powder particles, reduce the particle size of the solid material and reduce the dispersion resistance between the particles. Smaller particle size helps to increase the specific surface area of the powder, improve its dispersibility, make the emulsification more sufficient, increase the effective calcium content of the emulsion, and at the same time, the reduction of the powder particle size directly leads to the increase of the specific surface area, which increases the contact area between the powder particles and the liquid, which is beneficial to improve the permeability of the powder in the liquid and achieve the effect of rapid dispersion, thereby increasing the stability and rheology of the composite emulsion. The use of surfactants greatly increases the dispersibility and sedimentation of calcium-aluminum components, promotes their full contact with soluble phosphorus and fluorine pollutants in the phosphogypsum to be treated, and the treatment effect is stable. Thirdly, the first stirring operation is carried out to make the surfactant fully and uniformly cover the surface of the powder particles. And the slow-release agent is added drop by drop during preparation, which effectively controls the hydration process of the composite powder. This slow-release effect enables the emulsion to continuously and stably play a role in the wastewater treatment process, avoiding the fluctuation of the treatment effect caused by one-time large release. The subsequent second stirring ensures that the water and various components in the reaction system are fully mixed and uniform. The application solves the technical problems of traditional lime reagent that cannot simultaneously and efficiently remove phosphorus and fluorine due to low effective calcium content and poor permeability.

[0024] Further, in the preparation method of the present application, the surfactant is a non-ionic polyoxyethylene amide and a non-ionic polyacrylamide, wherein the polyoxyethylene amide type surfactant contains a polyoxyethylene chain, has good surface activity, is suitable for reducing interfacial tension, can provide surface activity, the polyoxyethylene amide type surfactant has good emulsifying effect, can stabilize emulsion and suspension, and has relatively strong adaptability, and can adapt to different pH values and different hardness of water. The non-ionic polyacrylamide (PAM) can make the precipitated substances generated during treatment fully settle down, reduce the precipitation time, enhance the treatment effect, at the same time improve the rheological property and increase the flocculation effect and solidification effect, and also improve the permeability of the emulsion and enhance the mass transfer performance.

[0025] The calcium-aluminum composite emulsion prepared by the above preparation method has the advantages of rapid and efficient synchronous precipitation of phosphorus and fluorine pollutants in water and phosphogypsum, can simultaneously meet the corresponding national standards of pH value, phosphorus and fluorine, and has stable precipitation effect and is not easy to release.

[0026] The calcium-aluminum composite emulsion prepared by the above preparation method has the advantages of rapid and efficient synchronous precipitation of phosphorus and fluorine pollutants in water and phosphogypsum, can simultaneously meet the corresponding national standards of pH value, phosphorus and fluorine, and has stable precipitation effect and is not easy to release. The calcium-aluminum composite emulsion prepared by the above preparation method has the advantages of rapid and efficient synchronous precipitation of phosphorus and fluorine pollutants in water and phosphogypsum, can simultaneously meet the corresponding national standards of pH value, phosphorus and fluorine, and has stable precipitation effect and is not easy to release.

[0027] Further, the calcium-aluminum composite emulsion also has high-efficiency precipitation performance. Experimental results show that after the emulsion is added into simulated wastewater, it can fully react with fluoride ions and phosphate ions in the wastewater within a short time (such as 0.5 hours) to form insoluble precipitates. This rapid reaction capability is due to the strong affinity of the calcium-aluminum composite components in the emulsion to fluoride ions and phosphate ions, which can deeply remove these pollutants and reduce their content in the wastewater to a very low level, making the treatment process more efficient. It can be known from experiments that the phosphate concentration in the simulated wastewater treated by the calcium-aluminum composite emulsion is lower than 0.5 mg / L, and the fluoride ion concentration is lower than 10 mg / L, thereby proving that the calcium-aluminum composite emulsion prepared by the application has high-efficiency removal effect on fluoride ions and phosphate ions in simulated wastewater. In summary, the calcium-aluminum composite emulsion prepared by the application has wide application prospect. It can be seen that the calcium-aluminum composite emulsion prepared by the application solves the technical problem that the traditional lime neutralization method cannot achieve that the three indicators of soluble phosphorus, soluble fluorine and pH value of the phosphorus chemical waste after treatment meet the standards. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A real photo of the new calcium-aluminum composite emulsion prepared for Example 1;

[0029] Figure 2 A curve of change of soluble phosphorus and fluorine over time for the phosphogypsum solidification of Example 10;

[0030] Figure 3 A curve of change of phosphorus and fluorine for the treatment of phosphorus-fluorine wastewater of Example 11. DETAILED DESCRIPTION

[0031] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0033] The present application will be further described in detail below in conjunction with the drawings and examples:

[0034] Example 1

[0035] Under room temperature and normal pressure, 15g of calcium oxide and 5g of aluminum oxide were ball milled, the ball milling method was dry milling, the ball milling beads were 5mm diameter agate beads, the rotation speed was set to 250 rpm, and the ball milling time was 2h;

[0036] 0.01g of polyoxyethylene amide nonionic surfactant, 0.02g of nonionic PAM were added to the ball milled composite powder in turn, 0.6ml of ethylene glycol was added dropwise while stirring with a glass rod, stirring was continued for 5min, and then it was left to stand for 2h;

[0037] After adding 200ml of water, stirring was continued for another 3h, and when the temperature dropped to room temperature, a calcium-aluminum composite emulsion was prepared, the measured value of dynamic viscosity was 0.31Pa·s, and the calcium-aluminum composite emulsion had high rheological properties.

[0038] Example 2

[0039] Under room temperature and normal pressure, 15g of calcium oxide and 5g of aluminum oxide were ball milled, the ball milling method was dry milling, the ball milling beads were 5mm diameter agate beads, the rotation speed was set to 250 rpm, and the ball milling time was 2.5h;

[0040] 0.02g of polyoxyethylene amide nonionic surfactant, 0.03g of nonionic PAM were added to the ball milled composite powder in turn, 0.6ml of ethylene glycol was added dropwise while stirring with a glass rod, stirring was continued for 5min, and then it was left to stand for 2h;

[0041] After adding 200ml of water, stirring was continued for another 3h, and when the temperature dropped to room temperature, a calcium-aluminum composite emulsion was prepared, the measured value of dynamic viscosity was 0.32Pa·s, and the calcium-aluminum composite emulsion had high rheological properties.

[0042] Example 3

[0043] The 14 g of calcium oxide and 6 g of aluminum oxide were ball milled under room temperature and normal pressure, the ball milling method was dry milling, the ball milling beads were 5 mm diameter agate beads, the rotation speed was set to 250 rpm, and the ball milling time was 2 h;

[0044] The 0.01 g of polyoxyethylene amide non-ionic surfactant and 0.02 g of non-ionic PAM were sequentially added to the ball milled composite powder, 1 ml of ethylene glycol was added dropwise while stirring with a glass rod, the stirring was continued for 5 min, and then it was left to stand for 2 h;

[0045] After adding 200 ml of water, the stirring was continued for another 3 h, and when the temperature dropped to room temperature, the calcium-aluminum composite emulsion was prepared, the dynamic viscosity was determined to be 0.33 Pa s, and the calcium-aluminum composite emulsion had high rheological properties.

[0046] Example 4

[0047] The 14 g of calcium oxide and 6 g of aluminum oxide were ball milled under room temperature and normal pressure, the ball milling method was dry milling, the ball milling beads were 5 mm diameter agate beads, the rotation speed was set to 250 rpm, and the ball milling time was 3 h;

[0048] The 0.01 g of polyoxyethylene amide non-ionic surfactant and 0.02 g of non-ionic PAM were sequentially added to the ball milled composite powder, 0.7 ml of ethylene glycol was added dropwise while stirring with a glass rod, the stirring was continued for 5 min, and then it was left to stand for 2 h;

[0049] After adding 200 ml of water, the stirring was continued for another 3 h, and when the temperature dropped to room temperature, the calcium-aluminum composite emulsion was prepared, the dynamic viscosity was determined to be 0.33 Pa s, and the calcium-aluminum composite emulsion had high rheological properties.

[0050] Example 5

[0051] The 14 g of calcium oxide and 6 g of aluminum oxide were ball milled under room temperature and normal pressure, the ball milling method was dry milling, the ball milling beads were 5 mm diameter agate beads, the rotation speed was set to 250 rpm, and the ball milling time was 3 h;

[0052] The 0.01 g of polyoxyethylene amide non-ionic surfactant and 0.02 g of non-ionic PAM were sequentially added to the ball milled composite powder, 0.8 ml of methanol was added dropwise while stirring with a glass rod, the stirring was continued for 5 min, and then it was left to stand for 2 h;

[0053] After adding 200 ml of water, continuously stirring for 2.5 h again, and waiting for the temperature to drop to room temperature, a calcium-aluminum composite emulsion is prepared, and the measured value is 0.31 Pa·s through dynamic viscosity determination. The calcium-aluminum composite emulsion has high rheological property.

[0054] Example 6

[0055] At room temperature and normal pressure, 14 g of calcium oxide and 6 g of aluminum oxide are ball milled. The ball milling method is dry milling, the ball milling beads are 5 mm diameter agate beads, the rotation speed is set to 250 rpm, and the ball milling time is 3 h.

[0056] To the ball-milled composite powder, 0.01 g of polyoxyethylene amide nonionic surfactant and 0.02 g of nonionic PAM are sequentially added, and 0.8 ml of glycerol is added dropwise while stirring with a glass rod. Stirring is continued for 5 min, and then the mixture is left to stand for 2 h.

[0057] After adding 200 ml of water, continuously stirring for 2.5 h again, and waiting for the temperature to drop to room temperature, a calcium-aluminum composite emulsion is prepared, and the measured value is 0.33 Pa·s through dynamic viscosity determination. The calcium-aluminum composite emulsion has high rheological property.

[0058] Example 7

[0059] At room temperature and normal pressure, 14 g of calcium oxide and 6 g of aluminum oxide are ball milled. The ball milling method is dry milling, the ball milling beads are 5 mm diameter agate beads, the rotation speed is set to 250 rpm, and the ball milling time is 3 h.

[0060] To the ball-milled composite powder, 0.01 g of polyoxyethylene amide nonionic surfactant and 0.02 g of nonionic PAM are sequentially added, and 0.8 ml of butanol is added dropwise while stirring with a glass rod. Stirring is continued for 5 min, and then the mixture is left to stand for 2 h.

[0061] After adding 200 ml of water, continuously stirring for 2.5 h again, and waiting for the temperature to drop to room temperature, a calcium-aluminum composite emulsion is prepared, and the measured value is 0.30 Pa·s through dynamic viscosity determination. The calcium-aluminum composite emulsion has high rheological property.

[0062] Example 8

[0063] At room temperature and normal pressure, 15 g of calcium oxide and 5 g of aluminum oxide are ball milled. The ball milling method is dry milling, the ball milling beads are 5 mm diameter agate beads, the rotation speed is set to 250 rpm, and the ball milling time is 3 h.

[0064] To the ball-milled composite powder, 0.02 g of polyoxyethylene amide nonionic surfactant and 0.02 g of nonionic PAM are sequentially added, and 1 ml of ethylene glycol is added dropwise while stirring with a glass rod. Stirring is continued for 5 min, and then the mixture is left to stand for 2 h.

[0065] After adding 200 ml of water, stirring for 3 h again, and waiting for the temperature to drop to room temperature, the calcium-aluminum composite emulsion was prepared. The dynamic viscosity was measured to be 0.35 Pa·s, and the calcium-aluminum composite emulsion had high rheological properties.

[0066] Example 9

[0067] At room temperature and normal pressure, 15 g of calcium oxide and 5 g of aluminum oxide were ball milled. The dry grinding method was used, the diameter of the agate beads was 5 mm, the rotation speed was set to 250 rpm, and the ball milling time was 3 h.

[0068] To the composite powder after ball milling, 0.02 g of polyoxyethylene amide nonionic surfactant and 0.02 g of nonionic PAM were added in sequence, and 1 ml of ethylene glycol was added dropwise while stirring with a glass rod. Stirring was continued for 10 min, and then the mixture was left to stand for 2 h.

[0069] After adding 200 ml of water, stirring for 3 h again, and waiting for the temperature to drop to room temperature, the calcium-aluminum composite emulsion was prepared. The dynamic viscosity was measured to be 0.36 Pa·s, and the calcium-aluminum composite emulsion had high rheological properties.

[0070] Example 10

[0071] At room temperature and normal pressure, the reaction steps were as follows: ① Under laboratory conditions, a phosphogypsum powder (dry basis about 10 g) was added to a 100 ml beaker, and the calcium-aluminum composite emulsion prepared in Example 1 was added at a dosage of 1.7% and stirred for 0.5 h to make it uniformly dispersed, and then left to stand for 6-24 hours. ② The solidified phosphogypsum was leached with pure water, and the initial concentration and the treated concentration of soluble phosphorus in the phosphogypsum were detected by spectrophotometer according to the National Standard for Determination of Total Phosphorus in Water (GB 11893-1989). ③ The initial concentration and the treated concentration of soluble fluorine in the phosphogypsum were detected by ion chromatography according to the National Standard for Detection of Fluoride Ions in Water (GB 11894-2014). ④ The initial pH value of the leaching solution was monitored by a pH meter, and the phosphogypsum in the experiment was further placed, and the above three indicators were detected again at different times, until two weeks after the solidification reaction. The experimental results showed that the reaction was fully occurred within 0.5 h, which meant that the active ingredients in the emulsion could rapidly react with the soluble phosphorus and fluorine in the phosphogypsum to form insoluble precipitates. The concentrations of the related substances in the leaching solution before and after 24 h were as shown in Table 1:

[0072] Table 1:

[0073]

[0074] According to the "GB 8978-1996 Integrated Wastewater Discharge Standard" and "GB 18599-2020 General Industrial Solid Waste Storage and Filling Pollution Control Standard", the soluble phosphorus is less than 0.5 mg / L, the soluble fluorine is less than 10 mg / L, and the pH value is between 6-9. After two weeks, the soluble phosphorus detection is less than the detection limit, the soluble fluorine detection value is 1.73 mg / L, and the pH value is stable between 7.1-7.3. The experiment proves the high efficiency of the calcium-aluminum composite emulsion in treating phosphogypsum, which can significantly reduce the concentration of soluble phosphorus and fluorine in a short time. The emulsion is expected to be used for harmless treatment of phosphogypsum, by reducing the concentration of soluble phosphorus and fluorine to meet the environmental protection standard, so as to realize the resource utilization of phosphogypsum. The experiment also shows that the treated phosphogypsum maintains a stable low concentration state for a long time and is not easy to release, which provides strong support for its practical application.

[0075] Example 11

[0076] In the laboratory, simulated wastewater was configured for treatment to observe the effect of the calcium-aluminum composite emulsion prepared by the present application. The first group of simulated wastewater contains F - = 400 mg / L, (PO4) 3- = 350 mg / L, pH = 4. According to the chemical equilibrium calculation result, 1% of the implementation of the emulsion is added to the water body, and the performance is excellent. Both groups of data meet the first level standard of "Integrated Wastewater Discharge Standard-GB8978-1996". Combined with the Figure 3 The experiment proves that the calcium-aluminum composite emulsion prepared by the present application has high removal effect on fluorine ions and phosphate ions in simulated wastewater. The emulsion is expected to be used in actual wastewater treatment, especially for wastewater containing high concentration of fluorine ions and phosphate ions. The treated wastewater meets the first level standard of national integrated wastewater discharge standard, indicating that the emulsion has practical application value.

[0077] The above content only illustrates the technical idea of the present application and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method for preparing a calcium-aluminum composite emulsion, characterized in that, include: After ball milling calcium oxide and aluminum oxide powders to obtain composite powder, a surfactant is added and stirred for the first time. During the first stirring, a slow-release agent is added. After standing, water is added to the reaction system and stirred for the second time. After natural cooling, a calcium-aluminum composite emulsion is obtained. The surfactant is a nonionic polyoxyethylene amide and a nonionic polyacrylamide, with a mass ratio of (1~2):(2~3). The slow-release agent includes one of ethylene glycol, methanol, glycerol or butanol, and the amount added is 3 ml to 5 ml of slow-release agent per 100 g of composite powder.

2. The method for preparing a calcium-aluminum composite emulsion according to claim 1, characterized in that, The mass ratio of calcium oxide to aluminum oxide powder is (14~15):(5~6).

3. The method for preparing a calcium-aluminum composite emulsion according to claim 1, characterized in that, Dry grinding is used in ball milling, with agate beads used for the grinding. The rotation speed is set to 250 rpm, and the grinding time is 2-3 hours.

4. The method for preparing a calcium-aluminum composite emulsion according to claim 1, characterized in that, The mass ratio of composite powder, nonionic polyoxyethylene amide and nonionic polyacrylamide is 200:(1~2):(2~3).

5. The method for preparing a calcium-aluminum composite emulsion according to claim 1, characterized in that, The first stirring time should be controlled at 5-10 minutes; the second stirring time should be 2-3 hours.

6. The calcium-aluminum composite emulsion prepared by the method of any one of claims 1 to 5.

7. The application of the calcium-aluminum composite emulsion according to claim 6 in the harmless treatment of phosphogypsum, characterized in that, The phosphogypsum treated with calcium-aluminum composite emulsion had soluble phosphorus content below 0.5 ppm and soluble fluoride content below 10 ppm, and the pH value was maintained at 8-10. After one month of exposure to air, the removal rates of soluble phosphorus and soluble fluoride in the treated phosphogypsum were 99.3% and 98.4%, respectively.

8. The application of the calcium-aluminum composite emulsion according to claim 6 in the treatment of phosphorus and fluoride wastewater, characterized in that, In wastewater treated with calcium-aluminum composite emulsion, the phosphate concentration is less than 0.5 mg / L and the fluoride ion concentration is less than 10 mg / L.

Images