Preparation method and application of phosphate tailing-based phosphorus-absorbing ball

Abstract

The invention provides a preparation method and application of phosphate tailing-based phosphorus uptake pellets, and the preparation method comprises the following steps: (1) mixing: uniformly mixing phosphate tailing powder, fly ash, slag powder and quicklime to obtain mixed powder; (2) a granulation step: intermittently putting the mixed powder into a disc granulator for granulation, and uniformly spraying water in a pressurized atomization manner in the granulation process so as to enable the mixed powder to form spherical particles in the rolling process, thereby obtaining a wet ball sample; and (3) curing: curing the wet ball sample to obtain the phosphate tailing-based phosphorus-absorbing ball. According to the method, the phosphate tailing solid waste serves as the main raw material and is converted into the efficient phosphorus adsorption material through the flow with the low cost, low energy consumption and the simple and convenient process, effective resourceful treatment of the phosphate tailings is achieved, a new technical approach is provided for sewage phosphorus removal, and remarkable environmental benefits and economic benefits are achieved.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, and relates to a method for preparing and applying phosphorus-absorbing balls based on phosphorus tailings. Background Technology

[0002] Phosphorus tailings, a major solid waste generated by the phosphate chemical industry, require efficient resource utilization to achieve the industry's green and sustainable development. Converting phosphorus tailings into adsorbent materials for phosphorus removal from water is a promising "waste-to-waste" approach. However, using phosphorus tailings directly in powder form carries the risk of phosphorus leaching, potentially causing secondary pollution. Particles prepared using simple crushing methods are irregular in shape and have poor uniformity, which can lead to increased pressure drop and channeling in practical applications (such as packed columns), affecting the system's hydraulic performance.

[0003] Disc granulation, as a mature and continuously operable molding process, can produce spherical particles with regular shapes and uniform particle sizes. For example, Reference 1 discloses a method for preparing phosphate rock pellets from phosphate rock gravity separation tailings: phosphate rock gravity separation tailings are mixed with an inorganic binder, and then an organic binder (sodium carboxymethyl cellulose solution) is added by spraying while disc granulation is being performed. The pellets are then prepared by drying and calcination. However, this method suffers from high cost and high energy consumption.

[0004] However, the use of phosphate tailings in the preparation of phosphate tailings-based adsorbent materials—especially granular products with high strength, high phosphorus adsorption activity, and no need for sintering—still faces technical challenges in areas such as formulation optimization and process parameter control. Furthermore, the stability, adaptability, and long-term effectiveness of these granular products in practical applications—whether they can meet the phosphorus removal needs of various complex water bodies, including municipal sewage, rural sewage, and agricultural non-point source pollution—require systematic evaluation and verification.

[0005] References:

[0006] Reference 1: CN117303325A Summary of the Invention

[0007] The problem the invention aims to solve

[0008] To address the aforementioned technical problems, this invention provides a method for preparing and applying phosphorus adsorption balls based on phosphorus tailings. Specifically, this method uses phosphorus tailings solid waste as the main raw material and transforms it into a highly efficient phosphorus adsorption material through a low-cost, low-energy-consumption, and simple process. This not only achieves effective resource utilization of phosphorus tailings but also provides a new technical approach for phosphorus removal from wastewater, demonstrating significant environmental and economic benefits.

[0009] Solution for solving the problem

[0010] It has been found that the above-mentioned technical problems can be solved by implementing the following technical solutions:

[0011] [1]. This invention provides a method for preparing phosphorus-absorbing balls based on phosphorus tailings, wherein the preparation method includes the following steps:

[0012] (1) Mixing step: Mix phosphorus tailings powder, fly ash, slag powder and quicklime to obtain mixed powder. The content of phosphorus tailings powder is 70~90 wt% based on the total dry mass of the mixed powder.

[0013] (2) Granulation steps: The mixed powder is intermittently fed into a disc granulator for granulation, and water is sprayed evenly in a pressurized atomizing manner during the granulation process so that the mixed powder forms spherical particles during the tumbling process, thus obtaining wet ball samples;

[0014] (3) Curing steps: Curing the wet bulb sample to obtain phosphorus adsorbent bulbs based on phosphorus tailings;

[0015] The total water consumption during the granulation process is 5-15 wt% of the mass of the mixed powder.

[0016] The average particle size of the phosphorus tailings-based phosphorus absorbent balls is 0.5~3cm.

[0017] [2]. According to the preparation method described in [1], in step (1),

[0018] Based on the total mass of the mixed powder, the content of fly ash is 5-15 wt%, the content of slag powder is 5-15 wt%, and the content of quicklime is 0.05-1 wt%.

[0019] [3]. According to the preparation method described in [1] or [2], wherein in step (1),

[0020] The mixing is carried out under stirring.

[0021] The mixing time is 2 to 20 minutes.

[0022] [4]. According to any one of [1]-[3], in step (2),

[0023] The rotating speed of the disc granulator is 20~40 r / min, and the tilt angle is 45~50°.

[0024] [5]. According to any one of [1]-[4], in step (2),

[0025] The granulation process also includes screening the spherical particles multiple times, returning the spherical particles that do not reach the target particle size to the disc granulator for further granulation.

[0026] [6]. According to any one of [1]-[5], in step (2),

[0027] The mixed powder is intermittently fed into a disc granulator, causing the particles in the granulator to grow layer by layer; the moisture content of the wet bulb sample is 5~15wt%.

[0028] [7]. According to any one of [1]-[6], in step (3),

[0029] The maintenance method is one or more of the following: natural air drying and constant temperature and humidity maintenance.

[0030] [8]. According to the preparation method described in [7], wherein,

[0031] The humidity for constant temperature and humidity curing is 75~85%RH;

[0032] The temperature for constant temperature and humidity curing is 20~30℃;

[0033] The constant temperature and humidity curing time is 5 to 15 days.

[0034] [9]. According to any one of [1]-[8], in step (3),

[0035] The compressive strength of the phosphorus tailings-based phosphorus absorbent sphere is not less than 50N.

[0036]

[10] . Application of phosphorus tailings-based phosphorus-absorbing balls prepared according to any one of [1]-[9] in phosphorus removal from wastewater;

[0037] The wastewater includes municipal domestic sewage, rural domestic sewage, or agricultural non-point source pollution water bodies.

[0038] The effects of the invention

[0039] 1) This invention realizes the efficient resource utilization of phosphorus tailings, with an admixture content of up to 90%, while allowing the amount of quicklime to be significantly reduced to 0.1%, thereby greatly reducing the cost of raw materials.

[0040] 2) This invention adopts a disc granulation process, which is mature and reliable and conducive to achieving continuous and stable large-scale production, with a daily production capacity of more than 1 ton.

[0041] 3) The phosphorus tailings-based phosphorus-absorbing balls prepared by this invention not only effectively alleviate the phosphorus leaching problem in the application of phosphorus tailings powder in water bodies, but also show excellent phosphorus absorption effects in various application scenarios such as municipal sewage, rural domestic sewage and phosphorus-containing water bodies in rivers around Dianchi Lake, with phosphorus absorption efficiencies exceeding 70% and reaching up to 94%.

[0042] 4) The present invention verified the phosphorus removal capacity of phosphorus tailings-based phosphorus absorbent balls in complex water bodies such as municipal sewage, rural sewage and agricultural non-point source pollution through small-scale and pilot-scale experiments. The results showed that it has good stability, adaptability and long-term effectiveness. Attached Figure Description

[0043] Figure 1 The image shows the morphology of the phosphorus tailings-based phosphorus-absorbing spheres prepared in Example 1.

[0044] Figure 2 The phosphorus adsorption effect of the phosphorus tailings-based phosphorus adsorbent balls prepared in Example 1 on municipal sewage is shown in the figure.

[0045] Figure 3 The phosphorus adsorption effect of the phosphorus tailings-based phosphorus adsorbing balls prepared in Example 1 on rural domestic sewage is shown in the figure.

[0046] Figure 4 The phosphorus absorption effect of the phosphorus tailings-based phosphorus-absorbing balls prepared in Example 1 in phosphorus-containing water bodies in rivers around Dianchi Lake is shown in the figure.

[0047] Figure 5 The figure shows the stability test results of the phosphorus tailings-based phosphorus adsorbing balls prepared in Example 1;

[0048] Figure 6 This is a comparison of the phosphorus absorption effects of the phosphorus tailings-based phosphorus-absorbing balls prepared in Example 1 and commercially available igneous rock fillers. Detailed Implementation

[0049] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0050] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0051] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0052] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0053] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0054] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0055] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0056] In this specification, the terms "comprising," "having," "including," or "containing" can mean included or open-ended, and do not exclude additional, uncited elements or method steps. At the same time, "comprising," "having," "including," or "containing" can also mean closed-ended, excluding additional, uncited elements or method steps.

[0057] In this specification, the word "about" is used to define the numerical ranges and parameters of the present invention, which are all approximate values. Specific related values ​​have been presented as precisely as possible. Unless otherwise explicitly stated, it should be understood that all ranges, quantities, values, and percentages used in the present invention are modified by the word "about". Here, "about" generally means that the actual value is within ±1% or ±0.5% of a specific value or range, depending on the industrially permissible error.

[0058] Unless otherwise stated, in this instruction manual, "more" in "multiple", "multi-variety", "multiple", etc., means a value of 2 or more.

[0059] Unless otherwise specified, “room temperature” or “room temperature” as used in this instruction manual usually refers to a temperature of 23±2℃.

[0060] <First Aspect>

[0061] The first aspect of the present invention provides a method for preparing phosphorus-absorbing balls based on phosphorus tailings, the method comprising the following steps:

[0062] (1) Mixing steps: Mix phosphorus tailings powder, fly ash, slag powder and quicklime to obtain mixed powder;

[0063] (2) Granulation steps: The mixed powder is intermittently fed into a disc granulator for granulation, and water is sprayed evenly in a pressurized atomizing manner during the granulation process so that the mixed powder forms spherical particles during the tumbling process, thus obtaining wet ball samples;

[0064] (3) Curing steps: Curing the wet bulb sample to obtain phosphorus tailings-based phosphorus adsorbing bulbs.

[0065] Mixing steps

[0066] In the mixing step of this invention, the main process is to mix phosphorus tailings powder, fly ash, slag powder and quicklime evenly to obtain a mixed powder.

[0067] In some embodiments, the phosphorus tailings powder of the present invention is used as the main raw material, which is derived from solid waste generated during the phosphate ore beneficiation process. Its main mineral components include fluorapatite, quartz, dolomite, etc., which not only provide an abundant calcium source, but also provide physical conditions for adsorption due to its porous structure.

[0068] In some embodiments, the fly ash used in this invention is preferably solid waste generated from coal-fired power plants, whose main component is amorphous glassy silica-alumina oxide. The highly reactive silica and alumina can serve as aluminosilicate precursors in the geopolymerization reaction, contributing to the formation of a three-dimensional network-like geopolymer gel structure, thereby enhancing the mechanical strength and stability of the phosphorus-absorbing spheres.

[0069] In some embodiments, the slag powder used in this invention is preferably a product obtained by grinding blast furnace slag, which contains a large amount of mineral components such as calcium silicate and calcium aluminate. Under alkaline conditions, it can be activated to participate in the gelation reaction, further optimizing the microstructure and long-term stability of the product.

[0070] In some embodiments, the quicklime (mainly composed of calcium oxide) used in this invention plays a dual role in the system. On the one hand, its hydration provides a strongly alkaline environment, which is key to activating the activity of fly ash and slag powder and promoting geopolymerization reactions. On the other hand, the calcium hydroxide generated by hydration can react with phosphate ions in wastewater to form insoluble precipitates such as hydroxyapatite, which is one of the main mechanisms by which phosphorus adsorption balls are used for phosphorus adsorption and removal.

[0071] In some embodiments, based on the total dry weight of the mixed powder, the content of the phosphorus tailings is 70-90 wt%, for example, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, etc.; the content of the fly ash is 5-15 wt%, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, etc.; the content of the slag powder is 5-15 wt%, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, etc.; and the content of the quicklime is 0.05-1 wt%, for example, 0.05 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, etc. This proportion ensures that phosphorus tailings are the main component, while a stable matrix is ​​constructed through the synergistic effect of fly ash and slag powder, and a small amount of quicklime provides the necessary alkalinity and calcium source.

[0072] In some embodiments, the mixing is carried out under stirring.

[0073] In some embodiments, the stirring speed is 50~500 r / min, for example, it can be 50 r / min, 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 450 r / min, etc. By controlling the stirring speed within the range of 50~500 r / min, dust flying or material stratification can be avoided, ensuring the mixing effect.

[0074] In some implementations, the stirring time is 2 to 20 minutes, for example, 2 minutes, 3 minutes, 5 minutes, 7 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, 20 minutes, etc. By controlling the stirring time within the range of 2 to 20 minutes, uniform mixing can be ensured while improving mixing efficiency.

[0075] Granulation steps

[0076] In the granulation step of the present invention, the mixed powder is mainly fed into a disc granulator for granulation, and water is sprayed evenly by pressurized atomization during the granulation process so that the mixed powder forms spherical particles during the tumbling process, thus obtaining a wet ball sample.

[0077] In some embodiments, the total water content during the granulation process is 5-15 wt% of the mass of the mixed powder, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, etc. Too little water will lead to difficulty in pelletizing and a rough surface; too much water will easily cause the particles to stick together or deform.

[0078] In some embodiments, the rotational speed of the disc granulator is 20~40 r / min, for example, 20 r / min, 25 r / min, 30 r / min, 35 r / min, 40 r / min, etc.; the inclination angle is 45~50°. The appropriate combination of rotational speed and inclination angle determines the rolling trajectory and residence time of the material in the disc, affecting the density and sphericity of the particles.

[0079] In some embodiments, to obtain a product with uniform particle size, the raw material powder is intermittently added to the granulator during the granulation process, allowing the particles in the granulator to grow continuously layer by layer, thereby ensuring the strength of the final particles. Furthermore, in some preferred embodiments, the granulation process includes multiple sieving of the spherical particles, returning those that do not meet the target particle size to the disc granulator for further granulation until a wet-bulb sample within the target particle size range is obtained. There are no particular limitations on the target particle size determined during sieving; it can be determined based on the actual processing conditions.

[0080] In some embodiments, the moisture content of the wet-bulb sample is 5-15 wt%, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, etc. This moisture content is beneficial for the reaction to proceed during subsequent curing.

[0081] Maintenance steps

[0082] The main step in the curing process of this invention is to cure the wet-bulb sample to obtain phosphorus-absorbing pellets based on phosphorus tailings.

[0083] In some implementation schemes, the maintenance method is one or more of natural air drying and constant temperature and humidity maintenance, preferably a combination of natural air drying and constant temperature and humidity maintenance. Combined maintenance (such as first maintaining constant temperature and humidity for a certain period of time to stabilize the structure, and then naturally curing until it reaches the service strength) can often balance quality control and energy economy.

[0084] When constant temperature and humidity curing is used, in some implementation schemes, the humidity during constant temperature and humidity curing is 75-85%RH, for example, 75%RH, 78%RH, 80%RH, 82%RH, 85%RH, etc. By controlling the humidity during constant temperature and humidity curing within the above range, it is possible to prevent excessively rapid evaporation of moisture from affecting the reaction.

[0085] In some implementations, the temperature for constant temperature and humidity curing is 20~30℃, for example, 20℃, 22℃, 25℃, 28℃, 30℃, etc. This temperature range is conducive to the development of reactivity and has low energy consumption.

[0086] In some implementations, the constant temperature and humidity curing time is 5 to 15 days, preferably 7 to 10 days, for example, 5 days, 7 days, 10 days, 12 days, 14 days, 15 days, etc. Sufficient curing time ensures the full hydration of quicklime, the dissolution of active components in fly ash and slag powder, and the full formation and hardening of the geopolymer gel network, thereby enabling the product to obtain ideal physicochemical properties.

[0087] In some embodiments, the average particle size of the phosphorus tailings-based phosphorus adsorbent balls is preferably 0.5-3 cm, more preferably 1-2 cm, for example, 0.5 cm, 0.8 cm, 1 cm, 1.2 cm, 1.3 cm, 1.5 cm, 1.8 cm, 2 cm, 2.2 cm, 2.5 cm, 2.8 cm, 3 cm, etc. This particle size range allows it to provide sufficient specific surface area to facilitate pollutant diffusion and adsorption when used as a wastewater treatment filler (such as constructed wetlands, ecological filters, adsorption beds, and packed columns), while maintaining good bed porosity to prevent water flow blockage.

[0088] In some embodiments, the compressive strength of the phosphorus tailings-based phosphorus absorbent sphere is not less than 50N, preferably 50~200N, for example, it can be 50N, 80N, 100N, 120N, 140N, 160N, 180N, 200N, etc. This strength is sufficient to ensure that it maintains structural integrity and is not easily broken during the filling, operation and backwashing of the sewage treatment facility.

[0089] <Second aspect>

[0090] The second aspect of the present invention provides the application of phosphorus tailings-based phosphorus-absorbing balls prepared by the preparation method described in the first aspect in wastewater phosphorus removal.

[0091] In some implementations, the wastewater includes municipal sewage, rural sewage, or agricultural non-point source pollution.

[0092] The phosphorus tailings-based phosphorus absorbent balls described in this invention not only achieve the goal of treating waste with waste and open up new avenues for the resource utilization of phosphorus tailings, but also have broad application prospects in the field of water environmental protection as a potential low-cost wastewater treatment material.

[0093] Example

[0094] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0095] Example 1:

[0096] 1) Mixing steps: Weigh out 80% of phosphorus tailings powder, 10% of fly ash, 10% of slag powder, and 0.1% of quicklime according to the following mass ratio. Add these four dry powder raw materials to a mixer and mix thoroughly to obtain a mixed powder. The bulk density of the mixed powder is measured to be 0.98 g / cm³. 3 The 325 mesh passing rate was 84.02%, and the moisture content after drying at 105℃ was calculated to be 0.54%.

[0097] 2) Disc granulation steps: The mixed powder is fed into a disc granulator. The disc inclination angle is set to 45°, and the equipment is started, rotating the disc at 30 r / min. Water is sprayed evenly onto the surface of the churning mixed powder using pressurized atomization. Under the action of water, the mixed powder gradually agglomerates to form small "mother spheres." Water spraying is then stopped, allowing the mother spheres to continue rolling and compacting within the disc, forming spherical particles. The surface of the spherical particles is then intermittently sprayed with water to moisten them, and a small amount of dry powder is sprinkled in as needed to promote the gradual growth of the spherical particles. The total water usage is approximately 12% of the total mass of the mixed powder.

[0098] 3) Sieving and particle size control: When the spherical particles grow to about 4 mm, the first sieving is performed, and the small particles that do not meet the standard are returned to the granulator to continue granulation. When the particle size of the spherical particles reaches about 8 mm, the second sieving is performed until all the powder is consumed and a wet pellet sample with uniform particle size is obtained.

[0099] 4) Curing steps: Place the wet bulb sample in a curing basin or designated curing area for 7-10 days of natural air drying and constant temperature and humidity curing. During the constant temperature and humidity curing period, maintain a humidity of approximately 80% RH and a temperature of approximately 20℃ to ensure the formation of phosphorus-absorbing pellets based on phosphorus tailings (such as...). Figure 1 As shown, the average particle size is about 13 mm, which forms a certain mechanical strength and achieves stable chemical properties.

[0100] Example 2:

[0101] The operation steps are the same as in Example 1, except that in step 1), phosphorus tailings powder, fly ash, slag powder and quicklime are mixed in a mass ratio of 90:5:5:0.1 to obtain mixed powder.

[0102] Example 3:

[0103] The operation steps are the same as in Example 1, except that in step 1), phosphorus tailings powder, fly ash, slag powder and quicklime are mixed in a mass ratio of 70:15:15:0.1 to obtain mixed powder.

[0104] Comparative Example 1:

[0105] The operation steps are the same as in Example 1, except that in step 1), phosphorus tailings powder, fly ash, slag powder and quicklime are mixed in a mass ratio of 60:20:20:0.1 to obtain mixed powder.

[0106] Comparative Example 2:

[0107] The operation steps are the same as in Example 1, except that quicklime is not added in step 1), and phosphorus tailings powder, fly ash and slag powder are mixed in a mass ratio of 80:10:10 to obtain mixed powder.

[0108] Comparative Example 3:

[0109] 1) Mixing steps: Weigh out 80% of phosphorus tailings powder, 10% of fly ash, 10% of slag powder, and 0.1% of quicklime according to the following mass ratio. Add these four dry powder raw materials to a mixer and mix thoroughly to obtain a mixed powder. The bulk density of the mixed powder is measured to be 0.98 g / cm³. 3 The 325 mesh passing rate was 84.02%, and the moisture content after drying at 105℃ was calculated to be 0.54%.

[0110] 2) Granulation step: The mixed powder is fed into a screw extruder for granulation. The total water consumption is about 12% of the total mass of the mixed powder.

[0111] 3) Curing steps: Place the wet bulb sample in a curing basin or designated curing area and allow it to air dry naturally for 7-10 days while maintaining constant temperature and humidity. During the constant temperature and humidity curing period, the humidity should be maintained at about 80%RH and the temperature at about 20℃ to obtain phosphorus tailings-based phosphorus adsorbing bulbs.

[0112] Performance testing :

[0113] Wet-bulb samples and dry-bulb samples (phosphorus tailings-based phosphorus adsorbing balls) prepared in the above examples and comparative examples were subjected to drop tests to detect the 1m free drop strength and the compressive strength of the samples. The results are shown in Table 1.

[0114] Table 1

[0115]

[0116] Adsorption phosphorus removal experiment :

[0117] Analysis of phosphorus adsorption effect in simulated phosphorus-containing wastewater: An appropriate amount of potassium dihydrogen phosphate was dissolved in deionized water to prepare simulated phosphorus-containing wastewater with a phosphate content of 2 mg / L. The samples prepared in each example and comparative example were mixed with the simulated phosphorus-containing wastewater (solid-liquid ratio 1 g: 10 mL), and the wastewater adsorption and phosphorus removal experiment was carried out at a stirring speed of 200 rpm. The results are shown in Table 2.

[0118] Table 2

[0119]

[0120] Analysis of phosphorus adsorption effect in actual phosphorus-containing wastewater: The phosphorus tailings-based phosphorus adsorption balls prepared in Example 1 were used to treat municipal domestic sewage, rural domestic sewage, and phosphorus-containing water bodies in rivers around Dianchi Lake. The experimental results showed that ( Figures 2-4 The phosphorus tailings-based phosphorus adsorption ball exhibits excellent phosphorus adsorption capacity for three types of phosphorus-containing water bodies. After 12 hours of adsorption, the total phosphorus concentration can be reduced to below 0.5 mg / L. After 3 days of stable adsorption, the phosphorus adsorption efficiency for municipal sewage, rural sewage, and phosphorus-containing water bodies in rivers around Dianchi Lake reaches 73%, 83%, and 94%, respectively, demonstrating excellent phosphorus removal capacity and wide applicability.

[0121] Furthermore, its stability was evaluated through 20 cycles of adsorption experiments. The experimental results showed that ( Figure 5 The phosphorus tailings-based phosphorus absorption ball can still maintain a phosphorus absorption efficiency of over 80% after multiple uses, indicating that it has good recyclability and stability.

[0122] Furthermore, the phosphorus adsorption effect of the phosphorus tailings-based phosphorus adsorbing balls prepared in Example 1 was compared with that of commercially available igneous rock fillers. The experimental results showed that ( Figure 6 The phosphorus adsorption balls provided by this invention have a significant phosphorus adsorption effect, while commercially available igneous rock fillers, which are commonly used fillers in constructed wetlands, have a relatively weak phosphorus adsorption effect.

[0123] Application effect verification :

[0124] Small-scale experimental results show that, under the conditions of an initial phosphate concentration of 400 mg / L, a dosage of phosphate tailings-based adsorbent pellets of 2 g / L, and a stirring speed of 200 rpm, a phosphorus removal rate of over 70% can be achieved within 30 minutes, with an equilibrium adsorption capacity of 80 mg / g. This performance is superior to that of traditional aluminum-based and iron-based adsorbent materials.

[0125] The pilot-scale treatment capacity was 3.5 m³ / d, with an influent total phosphorus concentration of 2 mg / L. Operational data showed that the effluent total phosphorus concentration could be stably controlled below 0.5 mg / L, and the service life of the phosphorus tailings-based phosphorus absorbent balls provided by this invention was no less than 15-20 days.

[0126] Cost accounting :

[0127] In terms of raw material costs, the market prices of fly ash and slag powder are between 100-150 yuan / ton and 200-300 yuan / ton, respectively, while quicklime is priced at approximately 400-500 yuan / ton. Based on the proportions, the raw material cost for producing one ton of finished product is approximately 100-200 yuan, demonstrating a strong cost advantage.

[0128] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0129] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing phosphorus-absorbing balls based on phosphorus tailings, characterized in that, The preparation method includes the following steps: (1) Mixing step: Mix phosphorus tailings powder, fly ash, slag powder and quicklime to obtain mixed powder. The content of phosphorus tailings powder is 70~90 wt% based on the total dry mass of the mixed powder. (2) Granulation steps: The mixed powder is intermittently fed into a disc granulator for granulation, and water is sprayed evenly in a pressurized atomizing manner during the granulation process so that the mixed powder forms spherical particles during the tumbling process, and wet ball samples are obtained; (3) Curing steps: Curing the wet bulb sample to obtain phosphorus adsorbent bulbs based on phosphorus tailings; The total water consumption during the granulation process is 5-15 wt% of the mass of the mixed powder. The average particle size of the phosphorus tailings-based phosphorus absorbent balls is 0.5~3cm.

2. The preparation method according to claim 1, characterized in that, In step (1), Based on the total dry weight of the mixed powder, the content of fly ash is 5-15 wt%, the content of slag powder is 5-15 wt%, and the content of quicklime is 0.05-1 wt%.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), The mixing is carried out under stirring. The mixing time is 2 to 20 minutes.

4. The preparation method according to any one of claims 1-3, characterized in that, In step (2), The rotating speed of the disc granulator is 20~40 r / min, and the tilt angle is 45~50°.

5. The preparation method according to any one of claims 1-4, characterized in that, In step (2), The granulation process also includes screening the spherical particles multiple times, returning the spherical particles that do not reach the target particle size to the disc granulator for further granulation.

6. The preparation method according to any one of claims 1-5, characterized in that, In step (2), The mixed powder is intermittently fed into a disc granulator, causing the particles in the granulator to grow layer by layer; the moisture content of the wet bulb sample is 5~15wt%.

7. The preparation method according to any one of claims 1-6, characterized in that, In step (3), The maintenance method is one or more of the following: natural air drying and constant temperature and humidity maintenance.

8. The preparation method according to claim 7, characterized in that, The humidity for constant temperature and humidity curing is 75~85%RH; The temperature for constant temperature and humidity curing is 20~30℃; The constant temperature and humidity curing time is 5 to 15 days.

9. The preparation method according to any one of claims 1-8, characterized in that, In step (3), The compressive strength of the phosphorus tailings-based phosphorus absorbent sphere is not less than 50N.

10. The application of the phosphorus tailings-based phosphorus-absorbing balls prepared by the preparation method according to any one of claims 1-9 in phosphorus removal from wastewater; in, The wastewater includes municipal domestic sewage, rural domestic sewage, or agricultural non-point source pollution water bodies.

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