Defluorination agent, preparation method thereof and treatment method of fluorine-containing wastewater

Abstract

The invention provides a defluorination agent, a preparation method thereof and a treatment method of fluorine-containing wastewater, the preparation method comprises the following steps: S1, adding an active component into water, and stirring to form a first solution; s2, adding the ferric salt into the first solution, adjusting the pH value, and then stirring to form a second solution; s3, adding the aluminum salt into the second solution, and stirring to form a third solution; s4, adding the calcium salt and the magnesium salt into the third solution, and stirring to form a fourth solution; s5, adding the adsorbent into the fourth solution, and stirring to form turbid liquid, so as to obtain the defluorination agent. The fluorine removal agent can effectively remove fluorine contained in water, enables effluent to reach corresponding national emission standards, and has the characteristics of simplicity in operation, low cost and suitability for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a defluorination agent and a preparation method thereof, and a method for treating fluorine-containing wastewater. Background Art

[0002] With the continuous innovation of science and technology, industrial technology has also made great progress, and the shortage of water resources and the deterioration of water quality have become increasingly serious. With the development of fluorine-related industries, fluorine pollution in my country's water environment has become increasingly serious. Fluorine-containing wastewater produced by industries such as metallurgy, chemical industry, ceramics, cement, and electronic manufacturing has become the main source of man-made fluorine pollution. Fluorine in water not only harms the environment, causing crops to fail to grow normally, but also affects people's bone health. Therefore, the control of fluorine content in water is related to human health and the safe use of water resources. The existing methods for removing fluoride ions mainly include chemical precipitation, adsorption, coagulation and sedimentation, reverse osmosis, electrodialysis, etc. These methods have more or less problems such as high processing cost and poor effect. Therefore, it is very necessary to develop a method for removing fluoride ions in wastewater that is highly practical and has good water purification effect. Summary of the invention

[0003] In view of the above problems, the present invention provides a defluorination agent and a preparation method thereof, and a method for treating fluoride-containing wastewater.

[0004] In the preparation method of the defluorination agent provided by the present invention, the defluorination agent is composed of active ingredients, iron salts, aluminum salts, calcium salts, magnesium salts and adsorbents, and the percentages of the components are 2-5%, 20%-30%, 30-55%, 15-20%, 5-10%, and 3-5%, respectively. The defluorination agent is a multi-nuclear complex mainly containing silicon, iron, aluminum, calcium and magnesium. The preparation method comprises the steps of:

[0005] S1, adding the active ingredient into water and stirring to form a first solution;

[0006] S2, adding the iron salt to the first solution, adjusting the pH value, and then stirring to form a second solution;

[0007] S3, adding the aluminum salt to the second solution, and stirring to form a third solution;

[0008] S4, adding the calcium salt and magnesium salt to the third solution, stirring, to form a fourth solution;

[0009] S5. Add the adsorbent into the fourth solution, stir to form a suspension, and obtain the defluorination agent.

[0010] further,

[0011] The active ingredient is one of the following materials: activated silicic acid, composite silicate, and polyaluminium-iron silicate.

[0012] further,

[0013] The iron salt is one of the following materials: ferric chloride, polyferric chloride, ferric sulfate, polyferric sulfate.

[0014] further,

[0015] The aluminum salt is one of the following materials: alum, aluminum chloride, polyaluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride iron, polyaluminum sulfate iron.

[0016] further,

[0017] The calcium salt is calcium chloride or calcium oxide;

[0018] The magnesium salt is one of the following materials: magnesium oxide, magnesium carbonate, and magnesium chloride.

[0019] further,

[0020] The adsorbent is one of the following materials: activated carbon, activated alumina, iron oxide, modified fly ash, modified bentonite, wherein the powder particle size is 200 meshes.

[0021] further,

[0022] In step S2, the pH value is adjusted to 2-3.

[0023] further,

[0024] Steps S1 to S5 are all stirred using a stirrer.

[0025] In step S1, the stirring speed is 400-800 r / min, and the stirring time, i.e., the reaction time, is 60-180 min;

[0026] In the steps S2 to S5, the stirring speed is 400-800 r / min, and the reaction time is 60-90 min.

[0027] The present invention also provides a defluorination agent, which is prepared by the defluorination agent preparation method.

[0028] The present invention also provides a method for treating fluorine-containing wastewater, wherein the above-mentioned defluorination agent is used for treatment.

[0029] The defluorination agent provided by the present invention can effectively remove fluorine contained in water, so that the effluent meets the corresponding national emission standards, and has the characteristics of simple operation, low cost, and suitability for industrial production. The treatment method has the characteristics of simple process flow, low agent consumption, low energy consumption, and effluent significantly lower than the national emission standards. The agent and treatment method are very suitable for various types of high-concentration and low-concentration fluoride-containing wastewater, and have good economic and social benefits.

[0030] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A flow chart of a method for preparing a defluorination agent according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", "third", etc. in the specification and claims of this application or the above-mentioned figures are used to distinguish different objects, not to describe a specific order or a primary and secondary relationship. "Multiple" appearing in this application refers to more than two (including two).

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] Figure 1 The present invention provides a flow chart of the preparation method of the defluorination agent. The defluorination agent is composed of active ingredients, iron salts, aluminum salts, calcium salts, magnesium salts and adsorbents, and the percentages of the components are 2-5%, 20%-30%, 30-55%, 15-20%, 5-10%, and 3-5%, respectively. The defluorination agent is a multi-nuclear complex mainly containing silicon, iron, aluminum, calcium and magnesium. Figure 1 The defluorination agent preparation method comprises the following steps.

[0037] S1. Add active ingredients into water and stir to form a first solution.

[0038] In this step, the stirring speed is 400-800 r / min (revolutions / minute), and the stirring time, i.e., the reaction time, is 60-180 min (minutes) to form a first solution.

[0039] The active ingredient is activated silicic acid, composite silicate, or polyaluminium-iron silicate.

[0040] S2. Adding iron salt to the first solution, adjusting the pH value, and then stirring to form a second solution.

[0041] In this step, the pH value is adjusted to 2-3, the stirring speed is 400-800 r / min, and the reaction time is 60-90 min to form a second solution. The pH value of the solution is adjusted using an acid and a base, the acid is hydrochloric acid or sulfuric acid solution, and the base is a sodium hydroxide solution.

[0042] The iron salt is ferric chloride, polyferric chloride, ferric sulfate, or polyferric sulfate.

[0043] S3, adding aluminum salt to the second solution, and stirring to form a third solution;

[0044] In this step, the stirring speed is 400-800 r / min, the reaction time is 60-90 min, and the third solution is formed.

[0045] The aluminum salt is alum, aluminum chloride, polyaluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride ferric, or polyaluminum sulfate ferric.

[0046] S4. Adding calcium salt and magnesium salt to the third solution and stirring to form a fourth solution.

[0047] In this step, the stirring speed is 400-800 r / min, the reaction time is 60-90 min, and a fourth solution is formed.

[0048] The calcium salt is calcium chloride or calcium oxide.

[0049] The magnesium salt is magnesium oxide, magnesium carbonate, or magnesium chloride.

[0050] S5. Add the adsorbent to the fourth solution and stir to form a suspension.

[0051] In this step, the stirring speed is 400-800 r / min, the reaction time is 60-90 min, and the formed suspension is the final defluorination agent, wherein the content of the effective ingredient is not less than 30%, and the pH value is 2-3.

[0052] The adsorbent is activated carbon, activated alumina, iron oxide, modified fly ash, or modified bentonite, wherein the powder particle size is 200 meshes.

[0053] The above steps are all stirred using a mixer.

[0054] The present invention also provides a method for treating fluorine-containing wastewater, comprising the following steps:

[0055] a) F in the fluorine-containing wastewater of the present invention - The concentration does not exceed 20 mg / L. - If the content exceeds 20 mg / L, conventional treatment methods are used to reduce the concentration to below 20 mg / L.

[0056] b) The fluorine-containing wastewater enters the mixing zone, the defluorination agent is added, and the defluorination agent is evenly dispersed in the fluorine-containing wastewater by mechanical stirring and other means.

[0057] c) The fluorine-containing wastewater mixed with the defluorination agent is transported to the neutralization area, and the pH value of the wastewater is adjusted to 6-9 to ensure the reaction effect. Acid and alkali are used to adjust the pH value of the fluorine-containing wastewater, the acid is hydrochloric acid or sulfuric acid solution, and the alkali is sodium hydroxide solution.

[0058] d) After adjusting the pH value, the fluorine-containing wastewater enters the flocculation zone, and anionic polyacrylamide is added and stirred.

[0059] e) The fluorine-containing wastewater with anionic polyacrylamide added enters the separation zone for mud-water separation, and the supernatant enters the water storage tank.

[0060] Embodiment 1:

[0061] A defluoridation agent, the percentages of the components are: 2% polyaluminium ferric silicate, 20% ferric chloride, 55% polyaluminium chloride, 15% calcium chloride, 5% magnesium oxide and 3% activated alumina. Among them, polyaluminium ferric silicate can be replaced by activated silicic acid or composite silicate; ferric chloride can be replaced by one of the following materials: polyferric chloride, ferric sulfate, polyferric sulfate; polyaluminium chloride can be replaced by one of the following materials: alum, aluminium chloride, aluminium sulfate, polyaluminium sulfate, polyaluminium ferric chloride, polyaluminium ferric sulfate; calcium chloride can be replaced by calcium oxide; magnesium oxide can be replaced by magnesium carbonate or magnesium chloride; activated alumina can be replaced by one of the following materials: activated carbon, iron oxide, modified fly ash, modified bentonite.

[0062] The defluorination agent is prepared by steps S1) to S5), and then the fluorine-containing wastewater is treated by steps a) to e). The stirring speed in steps S1 to S5 is 600 r / min, and the stirring time, i.e., the reaction time, is 60 min; and the pH value is adjusted to 2 in step S2.

[0063] Treatment of fluoride-containing wastewater - The concentration is 7.28mg / L, the amount of defluorination agent used is 2.0‰V / V (volume ratio), and the effluent effect is the effluent F - The concentration is 0.83mg / L.

[0064] Embodiment 2:

[0065] A defluoridation agent, the percentages of the components are: 3.0% polyaluminium ferric silicate, 24.3% ferric chloride, 44.6% polyaluminium chloride, 16.8% calcium chloride, 7.2% magnesium oxide and 4.1% activated alumina. Among them, polyaluminium ferric silicate can be replaced by activated silicic acid or composite silicate; ferric chloride can be replaced by one of the following materials: polyferric chloride, ferric sulfate, polyferric sulfate; polyaluminium chloride can be replaced by one of the following materials: alum, aluminium chloride, aluminium sulfate, polyaluminium sulfate, polyaluminium ferric chloride, polyaluminium ferric sulfate; calcium chloride can be replaced by calcium oxide; magnesium oxide can be replaced by magnesium carbonate or magnesium chloride; activated alumina can be replaced by one of the following materials: activated carbon, iron oxide, modified fly ash, modified bentonite.

[0066] The defluorination agent is prepared by steps S1) to S5), and then the fluorine-containing wastewater is treated by steps a) to e). The stirring speed in steps S1 to S5 is 600 r / min, the stirring time, i.e., the reaction time, is 120 min in step S1 and 75 min in the remaining steps; and the pH value is adjusted to 2.5 in step S2.

[0067] Treatment of fluoride-containing wastewater - The concentration is 15.9mg / L, the amount of defluoridation agent used is 4.0‰V / V, and the effluent effect is the effluent F -The concentration is 0.93mg / L.

[0068] Embodiment 3:

[0069] A defluoridation agent, the percentages of the components are: 5% polyaluminium ferric silicate, 30% ferric chloride, 30% polyaluminium chloride, 20% calcium chloride, 10% magnesium oxide and 5% activated alumina. Among them, polyaluminium ferric silicate can be replaced by activated silicic acid or composite silicate; ferric chloride can be replaced by one of the following materials: polyferric chloride, ferric sulfate, polyferric sulfate; polyaluminium chloride can be replaced by one of the following materials: alum, aluminium chloride, aluminium sulfate, polyaluminium sulfate, polyaluminium ferric chloride, polyaluminium ferric sulfate; calcium chloride can be replaced by calcium oxide; magnesium oxide can be replaced by magnesium carbonate or magnesium chloride; activated alumina can be replaced by one of the following materials: activated carbon, iron oxide, modified fly ash, modified bentonite.

[0070] The defluorination agent is prepared by steps S1) to S5), and then the fluorine-containing wastewater is treated by steps a) to e). The stirring speed in steps S1 to S5 is 800 r / min, the stirring time, i.e., the reaction time, is 180 min in step S1 and 90 min in the remaining steps; and the pH value is adjusted to 3 in step S2.

[0071] Treatment of fluoride-containing wastewater - The concentration is 18.3mg / L, the amount of defluoridation agent used is 5.0‰V / V, and the effluent effect is the effluent F - The concentration is 0.95mg / L.

[0072] The defluorination agent provided by the present invention can effectively remove fluorine contained in water, so that the effluent meets the corresponding national emission standards, and has the characteristics of simple operation, low cost, and suitability for industrial production. The treatment method has the characteristics of simple process flow, low agent consumption, low energy consumption, and effluent significantly lower than the national emission standards. The agent and treatment method are very suitable for various types of high-concentration and low-concentration fluoride-containing wastewater, and have good economic and social benefits.

[0073] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a defluorination agent, characterized in that: The defluorination agent is composed of active ingredients, iron salts, aluminum salts, calcium salts, magnesium salts and adsorbents, and the percentages of the components are 2-5%, 20%-30%, 30-55%, 15-20%, 5-10%, and 3-5%, respectively. The defluorination agent is a multi-nuclear complex mainly containing silicon, iron, aluminum, calcium and magnesium. The preparation method comprises the steps of: S1, adding the active ingredient into water and stirring to form a first solution; S2, adding the iron salt to the first solution, adjusting the pH value, and then stirring to form a second solution; S3, adding the aluminum salt to the second solution, and stirring to form a third solution; S4, adding the calcium salt and magnesium salt to the third solution, stirring, to form a fourth solution; S5. Add the adsorbent into the fourth solution, stir to form a suspension, and obtain the defluorination agent.

2. The method for preparing a defluorination agent according to claim 1, characterized in that: The active ingredient is one of the following materials: activated silicic acid, composite silicate, and polyaluminium-iron silicate.

3. The method for preparing a defluorination agent according to claim 1, characterized in that: The iron salt is one of the following materials: ferric chloride, polyferric chloride, ferric sulfate, polyferric sulfate.

4. The method for preparing a defluorination agent according to claim 1, characterized in that: The aluminum salt is one of the following materials: alum, aluminum chloride, polyaluminum chloride, aluminum sulfate, polyaluminum sulfate, polyaluminum chloride iron, polyaluminum sulfate iron.

5. The method for preparing a defluorination agent according to claim 1, characterized in that: The calcium salt is calcium chloride or calcium oxide; The magnesium salt is one of the following materials: magnesium oxide, magnesium carbonate, and magnesium chloride.

6. The method for preparing a defluorination agent according to claim 1, characterized in that: The adsorbent is one of the following materials: activated carbon, activated alumina, iron oxide, modified fly ash, modified bentonite, wherein the powder particle size is 200 meshes.

7. The method for preparing a defluorination agent according to any one of claims 1 to 6, characterized in that: In step S2, the pH value is adjusted to 2-3.

8. The method for preparing a defluorination agent according to any one of claims 1 to 6, characterized in that: Steps S1 to S5 are all stirred using a stirrer. In step S1, the stirring speed is 400-800 r / min, and the stirring time, i.e., the reaction time, is 60-180 min; In the steps S2 to S5, the stirring speed is 400-800 r / min, and the reaction time is 60-90 min.

9. A defluorination agent, characterized in that: The defluorination agent is prepared by the preparation method of any one of claims 1 to 8.

10. A method for treating fluorine-containing wastewater, characterized in that: The treatment is carried out using the defluorination agent described in claim 9.

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