A phosphorus-fluorine curing agent and its preparation method and application

Abstract

The present invention discloses a phospho-fluorine curing agent, its preparation method, and its application, belonging to the technical field of phosphogypsum processing. The phospho-fluorine curing agent contains Ca / Al / La LDH, is low-cost, can solidify harmful elements in phosphogypsum with a relatively small dosage, and realizes resource-based processing of phosphogypsum. The phospho-fluorine curing agent can be obtained by high-energy ball milling of its raw materials, a method that is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphogypsum processing, and in particular to a phosphorus-fluorine curing agent and a preparation method and application thereof. Background Art

[0002] Phosphogypsum, an industrial byproduct of producing phosphoric acid from natural phosphate rock through a wet process, is one of the most pressing issues in the field of environmental solid waste management. Phosphogypsum contains a large number of impurities (such as soluble phosphorus and fluorine), resulting in low resource utilization and requiring large-scale storage, resulting in the occupation of large amounts of land. Furthermore, harmful impurities in stored phosphogypsum are washed away by rainwater and leached by surface runoff, potentially causing safety and ecological damage. This severely restricts the development of phosphorus chemical companies and increases the investment, operation, and maintenance costs of these companies.

[0003] While phosphogypsum is currently being utilized in a variety of ways, including as a building material, chemical raw material, agriculture, environmentally friendly functional materials, fillers, carbon sequestration, and rare earth element extraction, these applications are insufficient to consume the vast amounts of accumulated and generated phosphogypsum. Therefore, treating the impurities in phosphogypsum has become a primary prerequisite for its resource utilization.

[0004] Existing methods for treating impurities in phosphogypsum fall roughly into two categories: separation and solidification. The former involves leaching impurities from phosphogypsum through methods such as water washing and chemical leaching, while the latter primarily involves decontaminating impurities in phosphogypsum through in-situ sealing, encapsulation, chelation, and precipitation to mitigate environmental pollution. Due to the large production volume, material extrusion, and high impurity content of phosphogypsum, the costs of water washing and chemical leaching are high. Furthermore, phosphogypsum is water-soluble, making large-scale absorption impossible.

[0005] The adsorption method is more suitable for recovering anions from the solution. The development of a curing agent that is low-cost, highly efficient, has a wide range of applications, uses less additives, and has good adsorption properties for harmful impurities in phosphogypsum is the key to curing harmful impurities in phosphogypsum.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a phosphorus-fluorine curing agent which has low cost, high efficiency, wide application range and can achieve the curing of harmful elements in phosphogypsum with a relatively small amount.

[0008] A second object of the present invention is to provide a method for preparing the above-mentioned phosphorus-fluorine curing agent.

[0009] A third object of the present invention is to provide an application of the above-mentioned phosphorus-fluorine curing agent.

[0010] This application can be implemented as follows:

[0011] In a first aspect, the present application provides a phosphorus-fluorine curing agent, which contains Ca / Al / La LDH.

[0012] In an optional embodiment, the raw materials for preparing the phosphorus-fluorine curing agent include calcium hydroxide, aluminum hydroxide and lanthanide rare earth salts.

[0013] In an optional embodiment, the preparation raw materials include 45-60 parts of calcium hydroxide, 30-50 parts of aluminum hydroxide and 5-15 parts of lanthanide rare earth salt, by weight.

[0014] In an optional embodiment, the lanthanide rare earth salt includes at least one of lanthanum carbonate, lanthanum chloride and cerium carbonate.

[0015] In an optional embodiment, the raw materials for preparing the phosphorus-fluorine curing agent further include a dispersant.

[0016] In an optional embodiment, the preparation raw materials contain 0.05-1 parts of dispersant.

[0017] In an alternative embodiment, the dispersant includes at least one of ethanol, triethanolamine, and silicone.

[0018] In a second aspect, the present application provides a method for preparing a phosphorus-fluorine curing agent according to any one of the aforementioned embodiments, comprising the following steps: subjecting the raw materials for preparing the phosphorus-fluorine curing agent to high-energy ball milling treatment.

[0019] In an optional embodiment, the high energy ball milling has at least one of the following characteristics:

[0020] Feature 1: Ball milling speed is 100r / min-650r / min;

[0021] Feature 2: Ball milling time is 0.5h-4h.

[0022] In an optional embodiment, the high energy ball milling further has at least one of the following characteristics:

[0023] Feature 3: The ball milling method is dry ball milling;

[0024] Feature 4: Ball-to-material ratio is 10:1 to 100:1;

[0025] Feature 5: The ball mills used for ball milling include planetary ball mills or stirring ball mills.

[0026] In a third aspect, the present application provides an application of the phosphorus-fluorine curing agent according to any of the aforementioned embodiments, which can be used, for example, to solidify at least one of soluble phosphorus and soluble fluorine in phosphogypsum.

[0027] In an optional embodiment, the added amount of the phosphorus-fluorine curing agent is 0.05 wt%-0.2 wt% of the phosphogypsum to be treated.

[0028] The beneficial effects of this application include:

[0029] The phospho-fluorine curing agent provided herein contains Ca / Al / La LDH. This low-cost, low-dosage phospho-fluorine curing agent can be used to cure harmful elements in phosphogypsum, thereby enabling resource recovery of phosphogypsum. This phospho-fluorine curing agent can be obtained by high-energy ball milling of its raw materials, a simple and easy-to-operate method. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 The XRD patterns of the raw materials used and the prepared phosphorus-fluorine curing agent in Example 1 are as follows;

[0032] Figure 2 The following are SEM images of the raw materials used and the prepared phosphorus-fluorine curing agent in Example 1;

[0033] Figure 3 The following are XRD patterns of the raw materials used in Example 1 and the prepared phosphorus-fluorine curing agent before and after phosphorus adsorption. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0035] The following is a detailed description of the phosphorus-fluorine curing agent provided in this application, as well as its preparation method and application.

[0036] The present application proposes a phosphorus-fluorine curing agent, which contains Ca / Al / La LDH and further contains CaO·Al2O3.

[0037] The above-mentioned Ca / Al / La LDH is a new hydrotalcite material, which has excellent phosphate adsorption performance and phosphorus and fluorine fixation effects, and can slow down the release of phosphorus.

[0038] It should be noted that using lanthanide compounds alone for the solidification of phosphorus and fluorine is costly. This application synthesizes Ca / Al / La LDH by mechanochemically combining lanthanide compounds with Ca-Al LDH, which not only reduces costs but also more effectively adsorbs and solidifies soluble phosphorus and soluble fluorine in phosphogypsum than using Ca-Al LDH or lanthanide compounds alone. Furthermore, light rare earth elements (lanthanum and cerium) are abundant and inexpensive, while medium and heavy rare earth elements (non-lanthanum and cerium rare earth elements) are expensive and have high costs.

[0039] For reference, the raw materials for preparing the above-mentioned phosphorus-fluorine curing agent may include calcium hydroxide, aluminum hydroxide and lanthanide rare earth salts. Furthermore, the raw materials may also include a dispersant to enable the various raw material components to be evenly dispersed and mixed.

[0040] In parts by weight, the raw materials for preparing the phosphorus-fluorine curing agent may include 45-60 parts of calcium hydroxide, 30-50 parts of aluminum hydroxide and 5-15 parts of lanthanide rare earth salt.

[0041] For example, the amount of calcium hydroxide can be 45 parts, 48 parts, 50 parts, 52 parts, 55 parts, 58 parts or 60 parts, etc., or any other value within the range of 45-60 parts.

[0042] The amount of aluminum hydroxide used can be 30 parts, 35 parts, 40 parts, 45 parts or 50 parts, etc., or any other value within the range of 30-50 parts.

[0043] The dosage of the lanthanide rare earth salt can be 5 parts, 8 parts, 10 parts, 12 parts or 15 parts, etc., or any other value within the range of 5-15 parts.

[0044] In some preferred embodiments, the total amount of calcium hydroxide, aluminum hydroxide and lanthanide rare earth salt is 100 parts.

[0045] It should be noted that when the amount of calcium hydroxide is less than 45 parts, it is not conducive to the formation of the hydrotalcite phase; when the amount of calcium hydroxide is greater than 60 parts, it is not conducive to obtaining a neutral product, and the product alkalinity is too high. When the amount of aluminum hydroxide is less than 30 parts, it is not conducive to the formation of the hydrotalcite phase; when the amount of aluminum hydroxide is greater than 50 parts, it is not conducive to fluorine and phosphorus curing. When the amount of lanthanide rare earth salt is less than 5 parts, it is not conducive to fluorine and phosphorus curing; when the amount of lanthanide rare earth salt is greater than 15 parts, it is not conducive to the formation of the hydrotalcite phase.

[0046] When the raw materials further include a dispersant, the raw materials also contain 0.05-1 parts of the dispersant.

[0047] For example, the amount of the dispersant may be 0.05 part, 0.1 part, 0.2 part, 0.5 part, 0.8 part or 1 part, etc., or any other value within the range of 0.05-1 part.

[0048] In the present application, the lanthanide rare earth salt may include at least one of lanthanum carbonate, lanthanum chloride, and cerium carbonate. The dispersant may include at least one of ethanol, triethanolamine, and organosilicon.

[0049] Accordingly, the present application also provides a method for preparing the above-mentioned phosphorus-fluorine curing agent, which may include the following steps: subjecting the raw materials for preparing the phosphorus-fluorine curing agent to high-energy ball milling treatment.

[0050] High-energy ball milling provides sufficient energy to form a phospho-fluoride curing agent containing Ca / Al / La LDH. Conventional ball milling, however, does not produce the phospho-fluoride curing agent containing the specific substances described in this application, even with the same raw materials.

[0051] For reference, the milling speed of the high energy ball mill can be 100r / min-650r / min, such as 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min, 500r / min, 550r / min, 600r / min or 650r / min, etc., or it can be any other value within the range of 100r / min-650r / min.

[0052] It should be noted that the milling speed of high-energy ball milling is less than 100 r / min, which is not conducive to the formation of hydrotalcite phase; the milling speed of high-energy ball milling is greater than 650 r / min, which is not conducive to low-cost production of materials.

[0053] The milling time of the high-energy ball mill can be 0.5 h-4 h, such as 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h, or any other value within the range of 0.5 h-4 h.

[0054] It should be noted that the milling time of high-energy ball milling is shorter than 0.5 h, which is not conducive to the formation of hydrotalcite phase; the milling time of high-energy ball milling is longer than 4 h, which is not conducive to low-cost production of materials.

[0055] In this application, dry ball milling is used for ball milling. It should be noted that if wet ball milling is used for ball milling, solid-phase chemical reaction cannot be induced to form a hydrotalcite phase.

[0056] During the ball milling process, the ball-to-material ratio can be 10:1 to 100:1, such as 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1 or 100:1, or any other value within the range of 10:1 to 100:1.

[0057] The ball mill used in the ball milling process may be, for example, a planetary ball mill or a stirring ball mill.

[0058] In addition, the present application also provides applications of the above-mentioned phosphorus-fluorine curing agent, for example, it can be used to solidify at least one of soluble phosphorus and soluble fluorine in phosphogypsum.

[0059] For reference, the amount of the phospho-fluorine curing agent added can be 0.05wt%-0.2wt% of the phosphogypsum to be treated, such as 0.05wt%, 0.1wt%, 0.15wt% or 0.2wt%, etc. In some specific embodiments, the amount of the phospho-fluorine curing agent added can be 0.1wt% of the phosphogypsum to be treated.

[0060] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0061] Example 1

[0062] This embodiment provides a phosphorus-fluorine curing agent, and its preparation method is as follows:

[0063] A mixture of calcium hydroxide, aluminum hydroxide and lanthanum carbonate (5 g, the mass percentage of the three is 45%:40%:15%) is placed in a 50 mL ball mill, and 0.1 wt% of the mixture mass of anhydrous ethanol is added. The mixture is ball milled in a planetary ball mill at a ball-to-material ratio of 10:1 and a ball milling speed of 650 r / min for 4 h to obtain a phosphorus-fluorine curing agent.

[0064] Example 2

[0065] This embodiment provides a phosphorus-fluorine curing agent, and its preparation method is as follows:

[0066] A mixture of calcium hydroxide, aluminum hydroxide and lanthanum chloride (5 g, the mass percentage of the three is 60%:30%:10%) is placed in a 50 mL ball mill, and 1 wt% of triethanolamine by mass of the mixture is added. The mixture is ball milled in a planetary ball mill at a ball-to-material ratio of 10:1 and a ball milling speed of 100 r / min for 0.5 h. After the ball milling is completed, a phosphorus-fluorine curing agent is obtained.

[0067] Example 3

[0068] This embodiment provides a phosphorus-fluorine curing agent, and its preparation method is as follows:

[0069] A mixture of calcium hydroxide, aluminum hydroxide and cerium carbonate (5 g, the mass percentage of the three is 60%:35%:5%) is placed in a 50 mL ball mill, and 1 wt% of triethanolamine by mass of the mixture is added. The mixture is ball milled in a planetary ball mill at a ball-to-material ratio of 10:1 and a ball milling speed of 300 r / min for 2 h to obtain a phosphorus-fluorine curing agent.

[0070] Example 4

[0071] This embodiment provides a phosphorus-fluorine curing agent, and its preparation method is as follows:

[0072] A mixture of calcium hydroxide, aluminum hydroxide and lanthanum carbonate (5 g, the mass percentage of the three is 60%:35%:5%) is placed in a 50 mL ball mill, and 1 wt% of triethanolamine by mass of the mixture is added. The mixture is ball milled in a planetary ball mill at a ball-to-material ratio of 10:1 and a ball milling speed of 300 r / min for 2 h to obtain a phosphorus-fluorine curing agent.

[0073] Example 5

[0074] A mixture of calcium hydroxide, aluminum hydroxide and lanthanum carbonate (5 g, the mass percentage of the three is 50%:45%:5%) is placed in a 50 mL ball mill, 0.05 wt% of the mixture mass of anhydrous ethanol is added, and the mixture is ball milled in a stirred ball mill at a ball-to-material ratio of 50:1 and a ball milling speed of 400 r / min for 1 h to obtain a phosphorus-fluorine curing agent.

[0075] Example 6

[0076] A mixture of calcium hydroxide, aluminum hydroxide and lanthanum carbonate (5 g, the mass percentage of the three is 45%:50%:5%) is placed in a 50 mL ball mill, 0.1 wt% of the mixture mass of anhydrous ethanol is added, and the mixture is ball milled in a planetary ball mill with a ball-to-material ratio of 100:1 and a ball milling speed of 500 r / min for 2 h. After ball milling, a phosphorus-fluorine curing agent is obtained.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is that the mass percentages of calcium hydroxide, aluminum hydroxide and lanthanum carbonate in the mixture are 40%:40%:20%.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 1 is that the mass percentages of calcium hydroxide, aluminum hydroxide and lanthanum carbonate in the mixture are 65%:20%:15%.

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is that the mass percentages of calcium hydroxide, aluminum hydroxide and lanthanum carbonate in the mixture are 30%:55%:15%.

[0083] Comparative Example 4

[0084] The difference between this comparative example and Example 1 is that the mass percentages of calcium hydroxide, aluminum hydroxide and lanthanum carbonate in the mixture are 58%:40%:2%.

[0085] Comparative Example 5

[0086] The difference between this comparative example and Example 1 is that the preparation raw materials do not contain lanthanum carbonate, and the phosphorus-fluorine curing agent component is mainly Ca-Al LDH.

[0087] Comparative Example 6

[0088] The difference between this comparative example and Example 1 is that the raw materials were conventionally mixed at a rotation speed of 50 rpm.

[0089] Comparative Example 7

[0090] The difference between this comparative example and Example 1 is that the ball milling method is wet ball milling.

[0091] Test example

[0092] ①, the phosphorus fluoride curing agent obtained in Example 1 and its preparation raw materials were subjected to XRD and SEM detection, and the results are as follows: Figure 1 and Figure 2 shown.

[0093] Depend on Figure 1 It can be seen that a new material of Ca / Al / La LDH hydrotalcite can be synthesized by high-energy ball milling treatment with Ca(OH)2, Al(OH)3 and La2(CO3)3 in a mass percentage of 45%:40%:15%.

[0094] Figure 2 (a) represents the SEM image of the phosphorus-fluoride curing agent obtained by mechanochemical synthesis of a mixture of calcium hydroxide, aluminum hydroxide and lanthanum carbonate after high-energy ball milling. Figure 2 (b) represents the SEM image of the phosphofluoride curing agent after phosphofluoride curing in water.

[0095] Depend on Figure 2 It can be seen that the phosphofluoride curing agent is in an amorphous state before the water-based phosphofluoride curing, and after the water-based phosphofluoride curing, the phosphofluoride curing agent is converted into a flaky structure.

[0096] ②. Taking the phosphorus-fluorine curing agent of Example 1-4 as an example, the ball milling time was changed, and the phosphorus-fluorine curing agents obtained corresponding to different ball milling times were used to cure the same phosphogypsum, and the addition amount of the phosphorus-fluorine curing agent was 0.1 wt%.

[0097] A. The curing rates of the above-mentioned phosphorus-fluorine curing agents for soluble phosphorus and soluble fluorine in phosphogypsum as a function of ball milling time are shown in Table 1.

[0098] Table 1 Changes in the curing rate of soluble phosphorus and soluble fluorine by phosphorus-fluorine curing agent with ball milling time

[0099]

[0100] It can be seen from Table 1 that with the increase of ball milling time, the curing effect of the fluorophosphorus curing agent in each embodiment on the soluble phosphorus and soluble fluorine in phosphogypsum is significantly improved.

[0101] B. Taking Example 1 as an example, the XRD patterns of the phosphorus-fluorine curing agent prepared therefrom before and after phosphorus adsorption are compared. The results are as follows: Figure 3 shown.

[0102] Depend on Figure 3 It can be seen that after adsorbing phosphorus, the curing agent produces calcium phosphate phase (CaPO3(OH)·2H2O) and lanthanum phosphate phase (LaPO4), indicating that the process is mainly based on chemical adsorption.

[0103] ③. Taking the phosphorus-fluorine curing agents of Examples 5-6 and Comparative Examples 1-7 as examples, the test was carried out according to the method ② above. The curing rates of the phosphorus-fluorine curing agents for soluble phosphorus and soluble fluorine in phosphogypsum corresponding to the ball milling time of 3 h are shown in Table 2.

[0104] Table 2 Curing rate results

[0105]

[0106] In summary, the present application adopts a high-energy ball milling method to convert calcium hydroxide, aluminum hydroxide and rare earth salts into a phosphofluoride curing agent containing Ca / Al / La LDH. The phosphofluoride curing agent has low cost and high efficiency, and can effectively solidify the harmful elements in phosphogypsum at a lower dosage, thereby realizing the resource utilization of phosphogypsum.

[0107] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An application of a phosphorus-fluorine curing agent, characterized in that: The phosphorus-fluorine curing agent is used to solidify the soluble phosphorus and soluble fluorine in the phosphogypsum; the addition amount of the phosphorus-fluorine curing agent is 0.05wt%-0.2wt% of the phosphogypsum to be treated; The phosphorus-fluorine curing agent contains Ca / Al / La LDH; the raw materials for preparing the phosphorus-fluorine curing agent are composed of 45-60 parts of calcium hydroxide, 30-50 parts of aluminum hydroxide, 5-15 parts of lanthanide rare earth salt and 0.05-1 part of dispersant in parts by weight; The lanthanide rare earth salt is selected from at least one of lanthanum carbonate, lanthanum chloride and cerium carbonate; the dispersant is selected from at least one of ethanol, triethanolamine and organosilicon; The preparation of the phosphorus-fluorine curing agent comprises: subjecting the raw materials to high-energy ball milling treatment; the ball milling speed is 100r / min-650r / min; the ball milling time is 0.5h-4h; the ball milling method is dry ball milling; and the ball-to-material ratio is 10:1 to 100:1.

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