Deep defluorination method for coal mine well water

Abstract

The invention belongs to the technical field of water treatment, and provides a method for deeply removing fluorine in coal mine water, which comprises the following steps: mixing aluminum salt, ferric salt and water to obtain a reagent A; mixing aluminum salt, a polyamine solution and water to obtain a reagent B; adding the reagent A into the fluorine-containing wastewater, and stirring for primary reaction to obtain a mixed solution C; adding the reagent B into the mixed solution C, and stirring for secondary reaction to obtain a mixed solution D; and adding a flocculating agent into the mixed solution D, stirring, then standing and settling, and discharging supernate which is up-to-standard effluent. According to the defluorination method provided by the invention, the dosing control system is adopted in the operation process to realize accurate control of the dosing amount of the defluorination agent, the agent input cost can be reduced, the dosing amount of the agent is reduced by more than 10% compared with that of a conventional defluorination agent, the standard discharge of effluent can be stably realized, and the defluorination method is suitable for industrial production; the defluorination reagent prepared by the invention has the advantages of high defluorination efficiency, convenience in use, low cost and the like.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a method for deep defluorination of coal mine water. Background Art

[0002] Coal mine water is a large amount of wastewater generated during the coal mining process, which contains a high concentration of fluoride, posing a serious threat to the environment and human health. The mine water produced during the coal mining process generally has a fluoride ion content of 1 to 4 mg / mL. Long-term drinking of water with excessively high fluoride content will cause harm to human health, such as plaque and fluorosis. With the increasing requirements of the state for the recycling and utilization of coal mine water resources, it is stipulated that the fluoride mass concentration of mine water must meet the Class III standard of "GB3838-2002 Surface Water Environmental Quality Standard", that is, the fluoride mass concentration is less than 1 mg / L. However, in the existing technology, efficient defluorination methods still have certain limitations. Therefore, there is an urgent need for an efficient, economical and environmentally friendly method for deep defluorination of coal mine water. Summary of the invention

[0003] The purpose of the present invention is to provide a method for deep defluorination of coal mine water to overcome the problems existing in the prior art.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for deep defluorination of coal mine water, comprising the following steps:

[0006] (1) mixing aluminum salt, iron salt and water to obtain reagent A;

[0007] (2) mixing aluminum salt, polyamine solution and water to obtain reagent B;

[0008] (3) adding reagent A into the fluorine-containing wastewater and stirring to react once to obtain a mixed solution C;

[0009] (4) adding reagent B to mixed solution C and stirring to perform a secondary reaction to obtain mixed solution D;

[0010] (5) Add flocculant to the mixed liquid D and stir it, then let it stand to settle. The supernatant is the effluent that meets the discharge standards.

[0011] Preferably, the aluminum salt in step (1) is one or both of iron-free aluminum sulfate and low-iron aluminum sulfate;

[0012] The iron salt is one or both of polyferric sulfate and polyferric chloride.

[0013] Preferably, in step (1), the mass ratio of aluminum salt, iron salt and water is 25-35:3-7:58-72.

[0014] Preferably, the aluminum salt in step (2) is one or both of iron-free aluminum sulfate and low-iron aluminum sulfate;

[0015] The polyamine solution comprises polydiallyldimethylamine ammonium chloride and water, and the mass fraction of the polydiallyldimethylamine ammonium chloride is 20-40%.

[0016] Preferably, in step (2), the mass ratio of aluminum salt, polyamine and water is 25-30:2-5:65-73.

[0017] Preferably, the amount of reagent A added in step (3) is 100-300 mg / L;

[0018] The time of the primary reaction is 3 to 5 minutes.

[0019] Preferably, the amount of reagent B added in step (4) is 30 to 80 mg / L;

[0020] The secondary reaction time is 3 to 5 minutes.

[0021] Preferably, the flocculant in step (5) is polyacrylamide.

[0022] Preferably, the amount of flocculant added in step (5) is 0.5 to 2.5 mg / L;

[0023] The stirring time is 1 to 3 minutes.

[0024] Beneficial effects:

[0025] Coal Mine Water - Generally, the concentration is 1-4 mg / L, which is low-concentration fluoride wastewater. After treatment, the discharge requirement is F - ≤1mg / L, the defluorination method of the present invention is suitable for coal mine water and low-concentration fluorine-containing wastewater in other industries. The defluorination method provided by the present invention adopts a dosing control system during operation to achieve precise control of the dosage of the defluorination agent, which can reduce the cost of the agent investment. The dosage of the agent is reduced by more than 10% compared with the conventional defluorination agent, and the effluent can be stably discharged up to the standard. It is suitable for industrial production. Compared with the prior art, the defluorination agent prepared by the present invention has the advantages of high defluorination efficiency, easy use, low cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The accompanying drawing is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides a method for deep defluorination of coal mine water, comprising the following steps:

[0028] (1) mixing aluminum salt, iron salt and water to obtain reagent A;

[0029] (2) mixing aluminum salt, polyamine solution and water to obtain reagent B;

[0030] (3) adding reagent A into the fluorine-containing wastewater and stirring to react once to obtain a mixed solution C;

[0031] (4) adding reagent B to mixed solution C and stirring to perform a secondary reaction to obtain mixed solution D;

[0032] (5) Add flocculant to the mixed liquid D and stir it, then let it stand to settle. The supernatant is the effluent that meets the discharge standards.

[0033] In the present invention, the aluminum salt in step (1) is preferably one or both of iron-free aluminum sulfate and low-iron aluminum sulfate;

[0034] The iron salt is preferably one or both of polyferric sulfate and polyferric chloride.

[0035] In the present invention, the mass ratio of aluminum salt, iron salt and water in step (1) is preferably 25-35:3-7:58-72, more preferably 27-33:4-6:60-70, and more preferably 29-31:4.5-5.5:63-67.

[0036] In the present invention, the aluminum salt in step (2) is preferably one or both of iron-free aluminum sulfate and low-iron aluminum sulfate;

[0037] In the present invention, the polyamine solution preferably comprises polydiallyldimethylamine ammonium chloride and water.

[0038] In the present invention, the mass fraction of the polydiallyldimethylamine ammonium chloride is preferably 20 to 40%, more preferably 22 to 38%, and even more preferably 25 to 35%.

[0039] In the present invention, the mass ratio of aluminum salt, polyamine and water in step (2) is preferably 25-30:2-5:65-73, more preferably 26-29:3-4:67-71, and more preferably 27-28:3.2-3.8:68-70.

[0040] In the present invention, the amount of reagent A added in step (3) is preferably 100 to 300 mg / L, more preferably 120 to 280 mg / L, and even more preferably 150 to 250 mg / L.

[0041] In the present invention, the time of the primary reaction is preferably 3 to 5 min, more preferably 3.2 to 4.8 min, and even more preferably 3.5 to 4.5 min.

[0042] In the present invention, the amount of reagent B added in step (4) is preferably 30 to 80 mg / L, more preferably 40 to 70 mg / L, and even more preferably 50 to 60 mg / L.

[0043] In the present invention, the secondary reaction time is preferably 3 to 5 min, more preferably 3.2 to 4.8 min, and even more preferably 3.5 to 4.5 min.

[0044] In the present invention, aluminum-iron composite salt and polyamine can form colloidal particles with large specific surface area in water, and these particles have positive charge and high Zeta potential, while fluoride ion radius is small and electronegative. This structure enables colloidal particles to have strong adsorption effect on fluoride ions, resulting in reduced Zeta potential, further agglomeration to form larger particles, and continue to react with flocculants, and finally form flocs and precipitate by utilizing the electrical neutralization, web laying and bridging effects of the macromolecules, thereby achieving the purpose of removing fluoride ions.

[0045] In the present invention, the flocculant in step (5) is preferably polyacrylamide.

[0046] In the present invention, the polyacrylamide can be cationic, anionic, or nonionic, and needs to be selected according to water quality.

[0047] In the present invention, the amount of flocculant added in step (5) is preferably 0.5 to 2.5 mg / L, more preferably 0.8 to 2.2 mg / L, and even more preferably 1 to 2 mg / L.

[0048] In the present invention, the stirring time is preferably 1 to 3 min, more preferably 1.2 to 2.8 min, and even more preferably 1.5 to 2.5 min.

[0049] In the present invention, in step (5), after the medium is allowed to stand and settle, a supernatant and a sludge can be obtained, wherein the supernatant is the effluent that meets the discharge standards, and the sludge is transported out through filter pressing.

[0050] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0051] Example 1

[0052] The iron-free aluminum sulfate, the polyferric sulfate and water were mixed and dissolved in a mass ratio of 25:3:72 to obtain reagent A.

[0053] Reagent B is obtained by mixing and dissolving iron-free aluminum sulfate, a polyamine solution containing 20% ​​polydiallyldimethylamine ammonium chloride by mass, and water in a ratio of 25:2:73.

[0054] Reagent A was added into the fluorine-containing wastewater at an amount of 100 mg / L, and stirred. The reaction was carried out for 3 minutes to obtain a mixed solution C.

[0055] Reagent B was added to the mixed solution C at an amount of 10 mg / L, and stirred. The mixture was reacted for 3 minutes to obtain a mixed solution D.

[0056] Add nonionic polyacrylamide to the mixed solution D at a dosage of 0.5 mg / L, stir for 1 min, and then let it stand to settle, to obtain a supernatant and sludge. The supernatant is the effluent that meets the discharge standards, and the sludge is transported out by filter pressing.

[0057] Example 2

[0058] The iron-free aluminum sulfate, polyferric chloride and water were mixed and dissolved in a mass ratio of 30:5:65 to obtain reagent A.

[0059] Reagent B is obtained by mixing and dissolving iron-free aluminum sulfate, a polyamine solution containing 40% polydiallyldimethylamine ammonium chloride by mass, and water in a ratio of 28:3:70.

[0060] Reagent A was added into the fluorine-containing wastewater at an amount of 150 mg / L, and stirred. The reaction was carried out for 4 minutes to obtain a mixed solution C.

[0061] Reagent B was added to the mixed solution C at an amount of 20 mg / L, and stirred, and a secondary reaction was performed for 4 minutes to obtain a mixed solution D.

[0062] Add nonionic polyacrylamide to the mixed solution D at a dosage of 1.0 mg / L, stir for 2 minutes, and then let it stand to settle, so as to obtain a supernatant and sludge. The supernatant is the effluent that meets the discharge standards, and the sludge is transported out by filter pressing.

[0063] Example 3

[0064] Low-iron aluminum sulfate, polyferric sulfate and water are mixed and dissolved in a mass ratio of 35:7:58 to obtain reagent A.

[0065] Low-iron aluminum sulfate, a polyamine solution containing 30% polydiallyldimethylamine ammonium chloride by mass, and water are mixed and dissolved in a ratio of 30:5:65 to obtain reagent B.

[0066] Reagent A was added into the fluorine-containing wastewater at an amount of 200 mg / L, and stirred. The reaction was carried out for 5 minutes to obtain a mixed solution C.

[0067] Reagent B was added to the mixed solution C at an addition amount of 30 mg / L, and stirred, and a secondary reaction was performed for 5 minutes to obtain a mixed solution D.

[0068] Add nonionic polyacrylamide to the mixed liquid D at an amount of 1.5 mg / L, stir for 2 minutes, and then let it stand to settle, and a supernatant and sludge can be obtained. The supernatant is the effluent that meets the discharge standards and can be discharged after meeting the standards. The sludge is transported out by filter pressing.

[0069] Example 4

[0070] Low-iron aluminum sulfate, polyferric chloride and water were mixed and dissolved in a mass ratio of 30:4:66 to obtain reagent A.

[0071] Low-iron aluminum sulfate, a polyamine solution containing 20% ​​polydiallyldimethylamine ammonium chloride by mass, and water are mixed and dissolved in a ratio of 28:2:70 to obtain reagent B.

[0072] Reagent A was added into the fluorine-containing wastewater at an amount of 250 mg / L, and stirred. The reaction was carried out for 4 minutes to obtain a mixed solution C.

[0073] Reagent B was added to the mixed solution C at an addition amount of 40 mg / L, and stirred, and a secondary reaction was performed for 5 minutes to obtain a mixed solution D.

[0074] Add nonionic polyacrylamide to the mixed solution D at an amount of 2.0 mg / L, stir for 2 minutes, and then let it stand to settle, so as to obtain a supernatant and sludge. The supernatant is the effluent that meets the discharge standards, and the sludge is transported out by filter pressing.

[0075] Example 5

[0076] The iron-free aluminum sulfate, the polyferric sulfate and water were mixed and dissolved in a mass ratio of 28:5:60 to obtain reagent A.

[0077] Reagent B is obtained by mixing and dissolving iron-free aluminum sulfate, a polyamine solution containing 40% polydiallyldimethylamine ammonium chloride by mass, and water in a ratio of 28:2:65.

[0078] Reagent A was added into the fluorine-containing wastewater at an amount of 300 mg / L, and stirred. The reaction was carried out for 5 minutes to obtain a mixed solution C.

[0079] Reagent B was added to mixed solution C at an amount of 50 mg / L, and stirred. The mixture was reacted for 5 minutes to obtain mixed solution D.

[0080] Add nonionic polyacrylamide to the mixed liquid D at a dosage of 2.5 mg / L, then stir for 1 minute and let it stand to settle, and a supernatant and sludge can be obtained. The supernatant is the effluent that meets the discharge standards, and the sludge is transported out by filter pressing.

[0081] Test results:

[0082] 1. The defluorination method of the present application and conventional defluorination agent (from Zibo Duxing Water Purifier Co., Ltd.) were used to remove F - The fluorine content of the coal mine water was 2.1 mg / L, and the supernatant obtained was 2.1 mg / L. - The test results are shown in Table 1.

[0083] Table 1F - The defluorinated liquid F is 2.1 mg / L - concentration

[0084]

[0085] It can be seen from Table 1 that when the reagent A and the conventional defluorinating agent are added in the same amount, the defluorinating rate of coal mine water can reach 69.52% by using the reagent and defluorinating method of the present application, which is 10.95% higher than that of the conventional defluorinating agent.

[0086] 2. Use the preparation method of this application and conventional defluorination agent to remove F - The fluorine content of the coal mine water was 3.9 mg / L. - The test results are shown in Table 2.

[0087] Table 2F - The defluorinated liquid F is 3.9 mg / L - concentration

[0088]

[0089] It can be seen from Table 2 that when the reagent A and the conventional defluorinating agent are added in the same amount, the defluorinating rate of coal mine water can reach 82.56% by using the reagent and defluorinating method of the present application, which is 5.64% higher than that of the conventional defluorinating agent.

[0090] It can be seen from the above embodiments that the present invention provides a method for deep defluorination of coal mine water. The defluorination method of the present invention is suitable for coal mine water and low-concentration fluorine-containing wastewater in other industries. The defluorination method provided by the present invention adopts a dosing control system during operation to achieve precise control of the dosage of the defluorination agent, which can reduce the cost of the agent investment. The dosage of the agent is reduced by more than 10% compared with conventional defluorination agents, and the standard discharge of effluent can be stably achieved. It is suitable for industrial production. Compared with the prior art, the defluorination agent prepared by the present invention has the advantages of high defluorination efficiency, easy use, low cost, etc.

[0091] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for deep defluorination of coal mine water, characterized in that: The following steps are involved: (1) mixing aluminum salt, iron salt and water to obtain reagent A; (2) mixing aluminum salt, polyamine solution and water to obtain reagent B; (3) adding reagent A into the fluorine-containing wastewater and stirring to react once to obtain a mixed solution C; (4) adding reagent B to mixed solution C and stirring to perform a secondary reaction to obtain mixed solution D; (5) Add flocculant to the mixed liquid D and stir it, then let it stand to settle. The supernatant is the effluent that meets the discharge standards.

2. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In the step (1), the aluminum salt is one or both of iron-free aluminum sulfate and low-iron aluminum sulfate; The iron salt is one or both of polyferric sulfate and polyferric chloride.

3. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In the step (1), the mass ratio of aluminum salt, iron salt and water is 25-35:3-7:58-72.

4. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In the step (2), the aluminum salt is one or both of iron-free aluminum sulfate and low-iron aluminum sulfate; The polyamine solution comprises polydiallyldimethylamine ammonium chloride and water, and the mass fraction of the polydiallyldimethylamine ammonium chloride is 20-40%.

5. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In the step (2), the mass ratio of aluminum salt, polyamine and water is 25-30:2-5:65-73.

6. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In step (3), the amount of reagent A added is 100-300 mg / L; The time of the primary reaction is 3 to 5 minutes.

7. The method for deep defluorination of coal mine water according to claim 1, characterized in that: The amount of reagent B added in step (4) is 10 to 80 mg / L; The secondary reaction time is 3 to 5 minutes.

8. The method for deep defluorination of coal mine water according to claim 1, characterized in that: In the step (5), the flocculant is polyacrylamide.

9. The method for deep defluorination of coal mine water according to claim 1, characterized in that: The amount of flocculant added in step (5) is 0.5 to 2.5 mg / L; The stirring time is 1 to 3 minutes.

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