Preparation method of phosphorus and fluorine fixing agent for phosphogypsum

Abstract

The invention discloses a preparation method of a phosphorus and fluorine fixing agent for ardealite, which comprises the following steps: adding a main material into a reaction kettle, then adding water and dissolving the main material to obtain a main material aqueous solution; adding a buffer solution and a stabilizer into the main material aqueous solution to obtain a mixed solution, stirring the mixed solution, and carrying out a reaction for 1.5-2 H; and cooling the liquid in the reaction kettle to 35-45 DEG C, and discharging to obtain the phosphorus and fluorine fixing agent. A small amount of stabilizer and acid-base buffer solution are added into the phosphorus-fixing fluorine-fixing agent for phosphogypsum, so that compounds in the phosphorus-fixing fluorine-fixing agent do not generate the phenomena of hydrolysis, precipitation and the like under the PH value of the use condition; and the phosphorus-fixing fluorine-fixing agent can rapidly react with free phosphorus and fluorine in phosphogypsum to form a structural phosphorus-fluorine compound, so that a relatively good phosphorus-fixing fluorine-fixing effect is achieved.

Description

Technical Field

[0001] This invention belongs to the field of phosphogypsum treatment technology, and particularly relates to a method for preparing a phosphorus and fluorine fixative for phosphogypsum. Background Technology

[0002] Phosphogypsum is a major waste product of phosphate rock. Due to its high content of free phosphorus and fluoride ions, it poses a certain degree of environmental harm. Fluoride and phosphorus ions in phosphogypsum exist in two forms: one is as free phosphorus and fluoride, such as sodium fluoride, potassium fluoride, fluorosilicic acid and their salts, and soluble phosphates, which can dissolve in water and form polluting ions. The other is in a bound form, such as calcium fluoride, aluminum fluoride, calcium fluoroaluminate, aluminum phosphate, and calcium phosphate, which have low Ksp values. The third form is bound to the phosphogypsum crystals, making them difficult to leach. For long-term landfill disposal, it is necessary to convert the free phosphorus and fluoride ions in phosphogypsum into structural phosphorus and fluoride compounds, reducing the Ksp value of these compounds and making them less likely to leach and pollute water resources.

[0003] Patent application CN118954987A discloses a process and agent for the harmless treatment of phosphogypsum. The process involves two stages: the first stage uses conventional alkaline neutralizing agents such as lime for neutralization; the second stage involves adding a composite agent composed of a calcium-based agent and a polyphosphate agent. The polyphosphate agent first etches the calcium sulfate crystals, releasing the eutectic phosphorus, fluorine, and heavy metal ions, and then reacts with the calcium-based agent to solidify the phosphogypsum. This second stage, requiring the use of lime and other agents for neutralization, increases the processing cost. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a method for preparing a phosphorus and fluorine fixative for phosphogypsum.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a method for preparing a phosphorus and fluorine fixing agent for phosphogypsum, comprising the following steps: A1: Add the main ingredient to the reaction vessel, then add water and dissolve the main ingredient to obtain an aqueous solution of the main ingredient. A2: Add buffer solution and stabilizer to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 1.5-2 hours. A3: The liquid in the reactor is cooled to 35-45℃ and discharged to obtain a phosphorus and fluorine fixation agent.

[0007] Preferably, a method for preparing a phosphorus and fluorine fixing agent for phosphogypsum includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water in an equal mass to the main ingredient. Heat the reaction vessel to 60-70℃ to dissolve the main ingredient, obtaining an aqueous solution of the main ingredient. A2: Add 7-15% (by weight of the main ingredient) of buffer solution and 3-7% (by weight of the main ingredient) of stabilizer to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 1.5-2 hours. A3: The liquid in the reactor is cooled to 35-45℃ and discharged to obtain a phosphorus and fluorine fixation agent.

[0008] Preferably, the buffer solution is acetic acid-ammonium acetate with a pH of 4.5-5.5.

[0009] Preferably, the main material includes one or more of aluminum salts, magnesium salts, calcium salts, and iron salts.

[0010] Preferably, the aluminum salt includes aluminum sulfate or aluminum chloride, the magnesium salt includes magnesium sulfate or magnesium chloride, the calcium salt is calcium chloride, and the iron salt is ferric chloride.

[0011] Preferably, the mass ratio of the aluminum salt, magnesium salt, calcium salt and iron salt is 1-5:1-3:2-4:0.1-1.5.

[0012] Preferably, the stabilizer is prepared by a stabilizer preparation device, which includes a stabilizer reactor, a first storage tank, a second storage tank, a condenser, a heat exchanger, and a gas-liquid separator. The gas outlet pipe of the stabilizer reactor is connected to the gas inlet of the condenser. The first and second storage tanks are respectively connected to the feed inlet of the stabilizer reactor through pipelines. The condenser is provided with gas outlet pipes that are respectively connected to the gas inlet of the stabilizer reactor and the gas inlet of the heat exchanger. The gas outlet pipe of the heat exchanger is connected to the gas inlet of the stabilizer reactor through the gas-liquid separator.

[0013] Preferably, the method for preparing the stabilizer includes the following steps: B1: Add unsaturated hydrocarbons, inhibitors and water to the stabilizer reactor and heat to 80-90℃; B2: Add the initiator solution dropwise while stirring, and control the temperature at 80-90℃. After the initiator is completely added, continue the reaction at 80-90℃ for 1-4 hours. B3: Cool to 30-40℃ to obtain the stabilizer.

[0014] Preferably, by mass percentage, the unsaturated hydrocarbon is 30-50%, the inhibitor is 10-20%, the water is 30-40%, and the initiator is 10-20% of the mass of the unsaturated hydrocarbon.

[0015] Preferably, the unsaturated hydrocarbon includes one or both of acrylic acid and hydroxypropyl acrylate, the inhibitor is isopropanol, and the initiator is potassium persulfate solution or hydrogen peroxide.

[0016] The beneficial effects of this invention are as follows: The phosphorus and fluoride fixative for phosphogypsum of the present invention contains a small amount of stabilizer and acid-base buffer solution, so that the compounds in the phosphorus and fluoride fixative do not undergo hydrolysis or precipitation under the pH value of the use conditions; and can react rapidly with free phosphorus and fluorine in phosphogypsum to form structural phosphorus and fluorine compounds, thereby achieving better phosphorus and fluoride fixation effect. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; In the diagram: 1-Stabilizer reactor, 2-First storage tank, 3-Second storage tank, 4-Condenser, 5-Heat exchanger, 6-Gas-liquid separator. Detailed Implementation

[0018] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0019] Example 1: like Figure 1 As shown, a method for preparing a phosphorus and fluorine fixative for phosphogypsum includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water of equal mass to the main ingredient. Heat the reaction vessel to 60°C to dissolve the main ingredient, obtaining an aqueous solution of the main ingredient. A2: Add 7% (by weight of the main ingredient) of buffer solution and 3% (by weight of the main ingredient) of stabilizer to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 1.5 hours to ensure uniform mixing and a transparent liquid. A3: The liquid in the reactor is cooled to 35°C and discharged to obtain a phosphorus and fluorine fixative.

[0020] The buffer solution is acetic acid-ammonium acetate with a pH of 4.5.

[0021] The main ingredients consist of aluminum salts, magnesium salts, calcium salts, and iron salts.

[0022] The aluminum salt is aluminum sulfate, the magnesium salt is magnesium sulfate, the calcium salt is calcium chloride, and the iron salt is ferric chloride.

[0023] The mass ratio of the aluminum salt, magnesium salt, calcium salt, and iron salt is 1:1:2:0.1.

[0024] The stabilizer is prepared by a stabilizer preparation device, which consists of a stabilizer reactor 1, a first storage tank 2, a second storage tank 3, a condenser 4, a heat exchanger 5, and a gas-liquid separator 6. The gas outlet pipe of the stabilizer reactor 1 is connected to the gas inlet of the condenser 4. The first storage tank 2 and the second storage tank 3 are respectively connected to the feed inlet of the stabilizer reactor 1 through pipes. The condenser 4 is provided with gas outlet pipes that are respectively connected to the gas inlet of the stabilizer reactor 1 and the gas inlet of the heat exchanger 5. The gas outlet pipe of the heat exchanger 5 is connected to the gas inlet of the stabilizer reactor 1 through the gas-liquid separator 6.

[0025] The method for preparing the stabilizer comprises the following steps: B1: Add acrylic acid, hydroxypropyl acrylate, isopropanol, and water to stabilizer reactor 1, and heat to 80°C. B2: Add potassium persulfate solution as an initiator dropwise while stirring, and control the temperature at 80℃. After the initiator is completely added, continue the reaction at 80℃ for 1 hour. This is an exothermic reaction, so avoid adding it too quickly to prevent bumping. B3: Cool to 30°C to obtain the stabilizer.

[0026] The unsaturated hydrocarbons comprise 50% by mass, the inhibitors comprise 20%, the water comprises 30%, and the initiator comprises 10% by mass of the unsaturated hydrocarbons.

[0027] Example 2: like Figure 1 As shown, a method for preparing a phosphorus and fluorine fixative for phosphogypsum includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water of equal mass to the main ingredient. Heat the reaction vessel to 70°C to dissolve the main ingredient, obtaining an aqueous solution of the main ingredient. A2: Add 15% (by weight of the main ingredient) of buffer solution and 7% (by weight of the main ingredient) of stabilizer to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 2 hours to ensure uniform mixing and a transparent liquid. A3: The liquid in the reactor is cooled to 45°C and discharged to obtain a phosphorus and fluorine fixative.

[0028] The buffer solution is acetic acid-ammonium acetate with a pH of 5.5.

[0029] The main ingredients consist of aluminum salts, magnesium salts, calcium salts, and iron salts.

[0030] The aluminum salt is aluminum chloride, the magnesium salt is magnesium chloride, the calcium salt is calcium chloride, and the iron salt is ferric chloride.

[0031] The mass ratio of the aluminum salt, magnesium salt, calcium salt, and iron salt is 5:3:4:1.5.

[0032] The stabilizer is prepared by a stabilizer preparation device, which consists of a stabilizer reactor 1, a first storage tank 2, a second storage tank 3, a condenser 4, a heat exchanger 5, and a gas-liquid separator 6. The gas outlet pipe of the stabilizer reactor 1 is connected to the gas inlet of the condenser 4. The first storage tank 2 and the second storage tank 3 are respectively connected to the feed inlet of the stabilizer reactor 1 through pipes. The condenser 4 is provided with gas outlet pipes that are respectively connected to the gas inlet of the stabilizer reactor 1 and the gas inlet of the heat exchanger 5. The gas outlet pipe of the heat exchanger 5 is connected to the gas inlet of the stabilizer reactor 1 through the gas-liquid separator 6.

[0033] The method for preparing the stabilizer comprises the following steps: B1: Add acrylic acid, hydroxypropyl acrylate, isopropanol, and water to stabilizer reactor 1, and heat to 80-90℃. B2: Add potassium persulfate solution as an initiator dropwise while stirring, and control the temperature at 90℃. After the initiator is completely added, continue the reaction at 90℃ for 4 hours. This is an exothermic reaction, so avoid adding it too quickly to prevent bumping. B3: Cool to 40℃ to obtain the stabilizer.

[0034] The unsaturated hydrocarbons comprise 45% by mass, the inhibitors comprise 20%, the water comprises 35%, and the initiator comprises 20% by mass of the unsaturated hydrocarbons.

[0035] Example 3: like Figure 1 As shown, a method for preparing a phosphorus and fluorine fixative for phosphogypsum includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water of equal mass to the main ingredient. Heat the reaction vessel to 65°C to dissolve the main ingredient, obtaining an aqueous solution of the main ingredient. A2: Add 10% (by weight of the main ingredient) of buffer solution and 5% (by weight of the main ingredient) of stabilizer to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 1.8 hours to ensure uniform mixing and a transparent liquid. A3: The liquid in the reactor is cooled to 40°C and discharged to obtain a phosphorus and fluorine fixative.

[0036] The buffer solution is acetic acid-ammonium acetate with a pH of 5.

[0037] The main ingredients consist of aluminum salts, magnesium salts, calcium salts, and iron salts.

[0038] The aluminum salt is aluminum chloride, the magnesium salt is magnesium sulfate, the calcium salt is calcium chloride, and the iron salt is ferric chloride.

[0039] The mass ratio of the aluminum salt, magnesium salt, calcium salt, and iron salt is 3:2:3:0.5.

[0040] The stabilizer is prepared by a stabilizer preparation device, which consists of a stabilizer reactor 1, a first storage tank 2, a second storage tank 3, a condenser 4, a heat exchanger 5, and a gas-liquid separator 6. The gas outlet pipe of the stabilizer reactor 1 is connected to the gas inlet of the condenser 4. The first storage tank 2 and the second storage tank 3 are respectively connected to the feed inlet of the stabilizer reactor 1 through pipes. The condenser 4 is provided with gas outlet pipes that are respectively connected to the gas inlet of the stabilizer reactor 1 and the gas inlet of the heat exchanger 5. The gas outlet pipe of the heat exchanger 5 is connected to the gas inlet of the stabilizer reactor 1 through the gas-liquid separator 6.

[0041] The method for preparing the stabilizer comprises the following steps: B1: Add acrylic acid, hydroxypropyl acrylate, isopropanol, and water to stabilizer reactor 1, and heat to 80-90℃. B2: Add hydrogen peroxide as an initiator dropwise while stirring, and control the temperature at 86℃. After the initiator is completely added, continue the reaction at 86℃ for 2 hours. This is an exothermic reaction, so avoid adding it too quickly to prevent bumping. B3: Cool to 40℃ to obtain the stabilizer.

[0042] The unsaturated hydrocarbons comprise 40% by mass, the inhibitors comprise 15%, the water comprises 35%, and the initiator comprises 15% by mass of the unsaturated hydrocarbons.

[0043] In Examples 1-3, the stabilizer reactor 1 is a reactor equipped with a stirrer and temperature control. The tube condenser 4 is equipped with a cooling water inlet, and the plate heat exchanger 5 is equipped with a cooling water outlet. The cooling water pipe of the tube condenser 4 is connected to the plate heat exchanger 5. The tube condenser 4, the plate heat exchanger 5, and the gas-liquid separator 6 are interconnected. During the production process, they play a role in continuously cooling and recovering the gasified material, ensuring the yield of the stabilizer.

[0044] During stabilizer preparation, the polymerization reaction is a strongly exothermic reaction. The gas generated in stabilizer reactor 1 enters from the bottom of tube condenser 4 for cooling, but the gas cannot be completely cooled and flows back into stabilizer reactor 1. Therefore, the uncooled gas is sent to plate heat exchanger 5 for secondary cooling. Plate heat exchanger 5 ensures that all gasified material returns to stabilizer reactor 1, preventing material loss and improving yield. Gas-liquid separator 6 is equipped with a drain pipe for discharging liquid. The function of gas-liquid separator 6 is to prevent material from being discharged along the drain pipe during reflux, also to improve yield.

[0045] The phosphogypsum prepared in Examples 1-3 was treated with a phosphorus and fluorine fixing agent, and the results are shown in the table below:

[0046] As shown in the table above, the phosphogypsum prepared in this application, when treated with a phosphorus and fluoride fixing agent, exhibits a significant reduction in the content of fluoride and phosphorus ions, and the leachate fully meets the national first-class discharge standard.

Claims

1. A method for preparing a phosphorus and fluorine fixing agent for phosphogypsum, characterized in that, Includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water and dissolve the main ingredient to obtain an aqueous solution of the main ingredient; A2: Add buffer solution and stabilizer to the aqueous solution of the main material to obtain a mixture. Stir the mixture and allow it to react for 1.5-2 hours. A3: The liquid in the reactor is cooled to 35-45℃ and discharged to obtain a phosphorus and fluorine fixation agent.

2. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 1, characterized in that, Includes the following steps: A1: Add the main ingredient to the reaction vessel, then add water in an equal mass to the main ingredient. Heat the temperature inside the reaction vessel to 60-70℃ to dissolve the main ingredient and obtain an aqueous solution of the main ingredient. A2: Add 7-15% buffer solution and 3-7% stabilizer by mass of the main ingredient to the aqueous solution of the main ingredient to obtain a mixture. Stir the mixture and allow it to react for 1.5-2 hours. A3: The liquid in the reactor is cooled to 35-45℃ and discharged to obtain a phosphorus and fluorine fixation agent.

3. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 1, characterized in that: The buffer solution is acetic acid-ammonium acetate with a pH of 4.5-5.

5.

4. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 1, characterized in that: The main ingredients include one or more of aluminum salts, magnesium salts, calcium salts, and iron salts.

5. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 4, characterized in that: The aluminum salt includes aluminum sulfate or aluminum chloride, the magnesium salt includes magnesium sulfate or magnesium chloride, the calcium salt is calcium chloride, and the iron salt is ferric chloride.

6. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 1, characterized in that: The mass ratio of the aluminum salt, magnesium salt, calcium salt and iron salt is 1-5:1-3:1:1-1.

5.

7. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 1, characterized in that: The stabilizer is prepared by a stabilizer preparation device, which includes a stabilizer reactor (1), a first storage tank (2), a second storage tank (3), a condenser (4), a heat exchanger (5), and a gas-liquid separator (6). The gas outlet pipe of the stabilizer reactor (1) is connected to the gas inlet of the condenser (4). The first storage tank (2) and the second storage tank (3) are respectively connected to the feed inlet of the stabilizer reactor (1) through pipelines. The condenser (4) is provided with gas outlet pipes that are respectively connected to the gas inlet of the stabilizer reactor (1) and the gas inlet of the heat exchanger (5). The gas outlet pipe of the heat exchanger (5) is connected to the gas inlet of the stabilizer reactor (1) through the gas-liquid separator (6).

8. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 7, characterized in that: The method for preparing the stabilizer includes the following steps: B1: Add unsaturated hydrocarbons, inhibitors and water to stabilizer reactor (1) and heat to a temperature of 80-90℃; B2: Add the initiator solution dropwise while stirring, and control the temperature at 80-90℃. After the initiator is completely added, continue the reaction at 80-90℃ for 1-4 hours. B3: Cool to 30-40℃ to obtain the stabilizer.

9. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 8, characterized in that: The unsaturated hydrocarbons comprise 30-50% by mass, the inhibitors comprise 10-20%, the water comprises 30-40%, and the initiator comprises 10-20% by mass of the unsaturated hydrocarbons.

10. The method for preparing a phosphorus and fluorine fixing agent for phosphogypsum as described in claim 8, characterized in that: The unsaturated hydrocarbon includes one or both of acrylic acid and hydroxypropyl acrylate, the inhibitor is isopropanol, and the initiator is potassium persulfate solution or hydrogen peroxide.

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