Mine water fluorine removal agent as well as preparation method and application thereof

Abstract

The invention discloses a mine water fluorine removal agent and a preparation method and application thereof, and belongs to the technical field of wastewater treatment.The preparation method of the fluorine removal agent comprises the following steps that aluminum salt, calcium salt, magnesium salt and ferric salt are added into water to be stirred, then a chelating agent, a hydroxy carboxylic acid compound and a dispersing agent are added, the mixture is heated to 40-60 DEG C to be stirred and dispersed, and heat preservation is conducted. The preparation method gets rid of the constraint of traditional calcium salt, introduces the chelating agent, the hydroxy carboxylic acid compound and the dispersing agent on the basis of controlling the compatibility of the materials and the synthesis reaction process, and utilizes the excellent fluorine ion adsorption performance and flocculation settling performance of the aluminum-calcium-magnesium-iron-based quaternary metal material to improve the fluorine ion adsorption performance of the aluminum-calcium-magnesium-iron-based quaternary metal material. Quaternary metals are assembled into a long-chain porous structure through chelation, the specific surface area and the pore volume are further increased, the contact area with fluorine ions in mine water is increased, and the porous structure adsorbs complexing groups to achieve the purposes of rapid coordination, strong adsorption, precise chelation, flocculating settling and efficient removal of fluoride in mine water.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a mine water fluorine removal agent and a preparation method and application thereof. BACKGROUND

[0002] The development of coal resources is mainly based on underground mine development, and a large amount of mine water is inevitably generated in the mining process. In China, about 6.9 billion tons of mine water are generated every year, and the average utilization rate is only 35%. Fluorine-containing mine water belongs to a special type of polluted mine water, and the mass concentration of fluorine ions in some coal mines even exceeds 10 mg / L, which has become an important factor restricting the efficient utilization of mine water. If such high-fluorine mine water is directly discharged without reasonable treatment, it may cause serious over-standard of fluorine ions in the surrounding groundwater, which seriously threatens human health. Therefore, it is of great practical significance to develop deep fluorine removal technology for high-fluorine mine water and improve the utilization rate of fluorine-containing mine water.

[0003] At present, the fluorine removal technology measures for fluorine-containing mine water mainly include coagulation sedimentation, adsorption, ion exchange, membrane treatment and the like. From the actual use, most of the fluorine removal technologies have low efficiency, poor economy, and are difficult to achieve standard discharge, which is mainly because the chemical particularity of fluorine element (difficult to oxidize, difficult to precipitate, and difficult to crystallize) determines that it is difficult to achieve deep purification. In addition, in the treatment of high-fluorine mine water, other types of pollutants may be contained, and a single treatment method often cannot achieve the ideal treatment effect, and a more efficient combined process treatment method needs to be researched. At present, polyaluminum chloride is commonly used as a fluorine removal coagulant. However, in actual engineering application, there are disadvantages such as low fluorine removal efficiency, poor stability, large dosage of reagent, high operation cost and the like. SUMMARY

[0004] The application aims to provide a mine water fluorine removal agent and a preparation method and application thereof, so as to solve the problem of low fluorine removal efficiency of the fluorine removal agent.

[0005] The object of the application can be achieved by the following technical solutions.

[0006] The application provides a preparation method of a mine water fluorine removal agent, which comprises the following steps:

[0007] The aluminum salt, calcium salt, magnesium salt and iron salt are added into water and stirred, and then a chelating agent, a hydroxyl carboxylic acid compound and a dispersant are added and heated and stirred for dispersion and heat preservation; the molar ratio of the aluminum salt, calcium salt, magnesium salt and iron salt is 1:(0.16-0.62):(0.09-0.36):(0.03-0.23).

[0008] In the actual defluorination process, the defluorination efficiency and economy need to be considered comprehensively according to different environments and defluorination requirements, so a more optimized and efficient defluorination technology is still needed in the direction of deep defluorination. The present application combines structure coordination, loading flocculation and adsorption technologies, and designs a reinforced flocculation defluorination integrated technology integrating coordination, flocculation and precipitation, which has good economy and application prospect. The reinforced flocculation defluorination technology can form a strong interaction with fluoride ions through the dense high-activity groups on the surface of the quaternary metal material, assemble the quaternary metal into a long-chain porous structure through chelation, further increase the specific surface area and pore volume, and be beneficial to increasing the contact area with fluoride ions in the mine water. The porous structure adsorbs the complexing groups to realize rapid coordination, strong adsorption, accurate chelation, flocculation and sedimentation, and efficient removal of fluoride in the mine water, so as to realize efficient and high-selectivity removal of fluoride ions in the fluorine-containing mine water and overcome the bottlenecks such as low efficiency and high cost in the deep purification of traditional defluorination technologies.

[0009] In some possible implementation manners, heating, stirring and dispersing, and heat preservation are performed: heating to 40-60 DEG C, stirring for 5-10 min, and heat preservation for 1-2 h.

[0010] In some possible implementation manners, the mass ratio of the chelating agent, the hydroxyl carboxylic acid compound and the dispersant is 2:2:1.

[0011] In some possible implementation manners, the mass ratio of the aluminum salt, the calcium salt, the magnesium salt, the iron salt, the chelating agent, the hydroxyl carboxylic acid compound and the dispersant is 10:2:1:1.

[0012] In some possible implementation manners, the mass ratio of the aluminum salt, the calcium salt, the magnesium salt, the iron salt, the chelating agent, the hydroxyl carboxylic acid compound and the dispersant is 10:2:1:1:0.2:0.2:0.1.

[0013] In some possible implementation manners, the aluminum salt is at least one of aluminum chloride, aluminum sulfate and aluminum nitrate;

[0014] The calcium salt is at least one of calcium chloride, calcium nitrate, calcium bicarbonate and calcium acetate;

[0015] The magnesium salt is at least one of magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium acetate;

[0016] The iron salt is at least one of ferric chloride, ferrous sulfate, ferrous sulfate, ferric ammonium sulfate and ferric nitrate.

[0017] In some possible implementation manners, the chelating agent is at least one of sodium tripolyphosphate, EDTA sodium salt, nitrilotriacetic acid and hydroxyethylidene diphosphonic acid;

[0018] In some possible implementation manners, the hydroxyl carboxylic acid compound is at least one of alpha-hydroxyacetic acid, salicylic acid, citric acid and lactobionic acid.

[0019] In some possible implementation manners, the dispersant is at least one of ethanol, propanol, polyethylene glycol, sodium silicate, polymethacrylic acid, polyethyleneimine and sodium dodecyl sulfate.

[0020] The second aspect of the present application provides a mine water defluorination agent prepared by the above method.

[0021] The third aspect of the present application provides application of the above mine water defluorination agent in mine water defluorination.

[0022] The application of the above mine water defluorination agent in mine water defluorination includes the following steps:

[0023] The defluorination agent is added to the fluorine-containing mine water, and after stirring and mixing reaction, a colloidal state is formed, then a flocculating agent is added to make the colloid form alum flowers, and the alum flowers are settled to obtain a clear liquid after defluorination.

[0024] In some possible implementation manners, the concentration of fluoride ions in the clear liquid after defluorination is <1 mg / L.

[0025] In some possible implementation manners, the flocculating agent is a polyacrylamide flocculating agent, the concentration of fluoride ions in the fluorine-containing mine water is 1-10 mg / L, the defluorination agent dosage is 0.05-0.1 wt%, the stirring rate is 200-300 rpm, the concentration of the polyacrylamide flocculating agent solution is 0.1 wt%, and the dosage is 0.1-0.2 wt%.

[0026] The present application has the following beneficial effects:

[0027] The present application breaks away from the shackles of traditional calcium salt, introduces key chelating agents, hydroxyl carboxylic acid compounds and dispersants on the basis of controlling the compatibility of the material and the synthesis reaction process, utilizes the excellent fluoride ion adsorption performance and flocculation and sedimentation performance of aluminum-calcium-magnesium-iron-based quaternary metal materials, assembles the quaternary metal into a long-chain porous structure through chelation under certain temperature conditions, further increases the specific surface area and pore volume, is conducive to increasing the contact area with fluoride ions in mine water, and realizes the purpose of rapid coordination, strong adsorption, precise chelation, flocculation and sedimentation and efficient removal of fluorides in mine water through the adsorption of complexing groups in the porous structure.

[0028] The present application adds hydroxyl carboxylic acid compound, so that the surface of the modified fluorine removal agent forms rich active groups such as hydroxyl and carboxyl, which can chemisorb with fluoride ions, thereby enhancing the fluorine removal capacity; on this basis, the hydroxyl carboxylic acid compound can also form long-chain polyhydroxy carboxylic acid, porous structure adsorption complexing copolymer through the synergistic effect between its multiple components and the chelating agent, further improving the fluoride ion removal rate and efficiency, and having the characteristics of complete removal, less sludge, economic efficiency and stable standard. At the same time, the long-chain polyhydroxy carboxylic acid has good organic compatibility, that is, even in organic-containing wastewater, the fluorine removal agent can effectively react with fluoride ions, thereby avoiding the negative influence of organic matter on the fluorine removal efficiency, and has broad application prospect.

[0029] The prepared mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect not only greatly improves the fluoride ion removal rate and efficiency of fluorine-containing mine water, but also can destroy the stable dispersion system in the mine water to achieve flocculation effect, and has good sedimentation performance. For fluorine-containing mine water in the range of 1-10 mg / L, the fluorine removal technology has good and efficient fluorine removal effect, and solves the disadvantages of low efficiency, poor stability, large reagent dosage and high operation cost of the existing fluorine removal technology. BRIEF DESCRIPTION OF DRAWINGS

[0030] The present application will be further described below in combination with the drawings.

[0031] Figure 1 is the SEM diagram of the fluorine removal agent prepared in Example 1 of the present application;

[0032] Figure 2 is the nitrogen adsorption-desorption curve diagram of the fluorine removal agent prepared in Example 1 of the present application;

[0033] Figure 3 is the treatment result of the fluorine removal agent (prepared in Example 1) in Application Example 1 on fluorine-containing mine water (fluorine concentration: 3 mg / L);

[0034] Figure 4 is the treatment result of the fluorine removal agent (prepared in Example 1) in Application Example 2 on fluorine-containing mine water (fluorine concentration: 5 mg / L);

[0035] Figure 5 is the treatment result of the fluorine removal agent (prepared in Example 1) in Application Example 3 on fluorine-containing mine water (fluorine concentration: 10 mg / L). DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0037] The following is a detailed description of a mine water defluorination agent, a preparation method and application thereof.

[0038] The following will be specifically described with reference to the embodiments.

[0039] Embodiment 1

[0040] The embodiment provides a preparation method of a mine water defluorination agent, comprising the following steps:

[0041] 200 g of aluminum chloride, 40 g of calcium chloride, 20 g of magnesium chloride and 20 g of iron chloride are added into 710 mL of deionized water, stirred at 200 rpm for 5 min, then 4 g of disodium ethylenediaminetetraacetate, 4 g of α-hydroxyacetic acid, 2 g of ethanol are added, and stirring is continued at 60 ℃ for 10 min under heating conditions, and after dissolution, the solution is incubated for 1 h, and the defluorination agent is obtained after cooling.

[0042] The defluorination agent prepared in Embodiment 1 is characterized by a scanning electron microscope (SEM) to characterize the morphology (SEM image), as shown in Figure 1 It can be seen that the prepared defluorination agent is a porous structure assembled by nanosheets (liquid, evaporation and drying are used for characterization). The specific surface area of the defluorination agent is characterized by a nitrogen adsorption-desorption curve, as shown in Figure 2 The specific surface area of the prepared defluorination agent is 168.1432 m 2 / g.

[0043] Application Example 1

[0044] The defluorination agent prepared in Embodiment 1 with the coordination-adsorption-chelation-flocculation synergistic effect is added into 1 L of mine water containing fluorine ions with a fluorine ion concentration of 3 mg / L at a dosage of 5-10 parts per million, and after stirring and mixing for 5 min at 200 rpm, a colloidal state is formed, then 1 mL of polyacrylamide solution is added and stirred for 3 min, so that the colloid forms alunite flowers, and after standing and settling for 5 min, the clear liquid after defluorination is obtained.

[0045] The treatment results of the mine water containing fluorine ions are shown in Figure 3 When the fluorine ion concentration in the mine water containing fluorine ions is 3 mg / L, the fluorine ion concentration of the effluent gradually decreases with the increase of the dosage of the defluorination agent; when the dosage is 5 parts per million, the fluorine ion concentration of the effluent can be reduced to below 1 mg / L.

[0046] Application Example 2

[0047] The fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in Example 1 was added into 1 L fluorine ion concentration of 5 mg / L fluorine-containing mine water at a dosage of 5-10 parts per million, respectively, and stirred at 200 rpm for 5 min, then 1 mL of polyacrylamide solution was added, and stirred and mixed uniformly, and then settled for 5 min to obtain the clear liquid after fluoride removal.

[0048] The treatment results of fluorine-containing mine water are shown in Table 1. Figure 4 As shown in Table 1, when the fluorine ion concentration in the fluorine-containing mine water was 5 mg / L, the effluent fluorine ion concentration gradually decreased with the increase of the dosage of the fluoride removal agent; when the dosage was 6 parts per million, the effluent fluorine ion concentration could be reduced to below 1 mg / L.

[0049] Application Example 3

[0050] The fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in Example 1 was added into 1 L fluorine ion concentration of 5 mg / L fluorine-containing mine water at a dosage of 5-10 parts per million, respectively, and stirred at 200 rpm for 5 min, then 1 mL of polyacrylamide solution was added, and stirred and mixed uniformly, and then settled for 5 min to obtain the clear liquid after fluoride removal.

[0051] The treatment results of fluorine-containing mine water are shown in Table 1. Figure 5 As shown in Table 1, when the fluorine ion concentration in the fluorine-containing mine water was 5 mg / L, the effluent fluorine ion concentration gradually decreased with the increase of the dosage of the fluoride removal agent; when the dosage was 6 parts per million, the effluent fluorine ion concentration could be reduced to below 1 mg / L.

[0052] Example 2

[0053] The present embodiment provides a preparation method of a mine water fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect, comprising the following steps: adding 200 g of aluminum sulfate, 40 g of calcium nitrate, 20 g of magnesium sulfate, and 20 g of ferric sulfate into 710 mL of deionized water, stirring at 200 rpm for 10 min, then adding 4 g of sodium tripolyphosphate, 4 g of α-hydroxyacetic acid, and 2 g of polyethylene glycol, and continuing to stir at 60°C for 5 min, stirring and dissolving, and then keeping warm for 1 h, and then cooling to obtain a liquid fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect.

[0054] The fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in Example 2 was used to remove fluoride from fluorine-containing mine water with different fluorine ion concentrations according to the methods of Application Examples 1-3. When the fluorine ion concentration in the fluorine-containing mine water was 3, 5, and 10 mg / L, and the dosage of the fluoride removal agent was 5, 6, and 8 parts per million, respectively, the effluent fluorine ion concentration could be reduced to below 1 mg / L.

[0055] Example 3

[0056] The embodiment provides a preparation method of a mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect, and the method comprises the following steps: adding 200g of aluminum nitrate, 40g of calcium nitrate, 20g of magnesium nitrate and 20g of iron nitrate into 710mL of deionized water, stirring at 200rpm for 10min, then adding 4g of nitrilotriacetic acid, 4g of salicylic acid and 2g of sodium silicate, continuing to stir for 5min under the condition of heating at 40 DEG C, keeping warm for 2h after dissolving, and obtaining the mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect after cooling.

[0057] The mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in the embodiment 3 is used for fluorine removal test on fluorine-containing mine water with different fluorine ion concentrations according to the methods in the application examples 1 to 3. When the fluorine ion concentration in the fluorine-containing mine water is 3, 5 and 10mg / L, the fluorine removal agent is added in the amount of 5 / 10,000, 6 / 10,000 and 8 / 10,000, and the fluorine ion concentration in the effluent can be reduced to below 1mg / L.

[0058] Embodiment 4

[0059] The embodiment provides a preparation method of a mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect, and the method comprises the following steps: adding 200g of aluminum nitrate, 40g of calcium nitrate, 20g of magnesium nitrate and 20g of iron nitrate into 710mL of deionized water, stirring at 200rpm for 10min, then adding 4g of nitrilotriacetic acid, 4g of salicylic acid and 2g of sodium silicate, continuing to stir for 5min under the condition of heating at 40 DEG C, keeping warm for 2h after dissolving, and obtaining the mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect after cooling.

[0060] The mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in the embodiment 4 is used for fluorine removal test on fluorine-containing mine water with different fluorine ion concentrations according to the methods in the application examples 1 to 3. When the fluorine ion concentration in the fluorine-containing mine water is 3, 5 and 10mg / L, the fluorine removal agent is added in the amount of 5 / 10,000, 6 / 10,000 and 8 / 10,000, and the fluorine ion concentration in the effluent can be reduced to below 1mg / L.

[0061] Embodiment 5

[0062] The embodiment provides a preparation method of a mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect, and the method comprises the following steps: adding 200g of aluminum nitrate, 40g of calcium nitrate, 20g of magnesium nitrate and 20g of iron nitrate into 710mL of deionized water, stirring at 200rpm for 10min, then adding 4g of nitrilotriacetic acid, 4g of salicylic acid and 2g of sodium silicate, continuing to stir for 5min under the condition of heating at 40 DEG C, keeping warm for 2h after dissolving, and obtaining the mine water fluorine removal agent with coordination-adsorption-chelation-flocculation synergistic effect after cooling.

[0063] The fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in Example 5 was used to remove fluoride from fluorine-containing mine water with different fluoride ion concentrations according to the methods of Application Examples 1-3. When the fluoride ion concentration in the fluorine-containing mine water was 3, 5, and 10 mg / L, and the dosage of the fluoride removal agent was 5, 6, and 8 parts per million, respectively, the fluoride ion concentration in the effluent could be reduced to below 1 mg / L.

[0064] Example 6

[0065] The present example provides a preparation method of a mine water fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect, which comprises the following steps: adding 200 g of aluminum chloride, 40 g of calcium bicarbonate, 20 g of magnesium acetate, and 20 g of ferric ammonium sulfate into 710 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of nitrilotriacetic acid, 4 g of salicylic acid, and 2 g of sodium dodecyl sulfate, continuing to stir at 60°C for 5 min, and after dissolution, incubating for 1 h, and then cooling to obtain the mine water fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect.

[0066] The fluoride removal agent with coordination-adsorption-chelation-flocculation synergistic effect prepared in Example 6 was used to remove fluoride from fluorine-containing mine water with different fluoride ion concentrations according to the methods of Application Examples 1-3. When the fluoride ion concentration in the fluorine-containing mine water was 3, 5, and 10 mg / L, and the dosage of the fluoride removal agent was 5, 6, and 8 parts per million, respectively, the fluoride ion concentration in the effluent could be reduced to below 1 mg / L.

[0067] Comparative Example 1

[0068] The present comparative example provides a preparation method of a mine water fluoride removal agent, which comprises the following steps: adding 160 g of aluminum chloride, 40 g of calcium chloride, 40 g of magnesium chloride, and 40 g of iron chloride into 710 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of disodium ethylenediaminetetraacetate, 4 g of α-hydroxyacetic acid, and 2 g of ethanol, continuing to stir at 40°C for 5 min, incubating for 1 h, and then cooling to obtain the fluoride removal agent.

[0069] The fluoride removal agent prepared in Comparative Example 1 was used to remove fluoride from fluorine-containing mine water with different fluoride ion concentrations according to the methods of Application Examples 1-3. The results showed that when the mass ratio of “aluminum salt, calcium salt, magnesium salt, iron salt, chelating agent, hydroxycarboxylic acid compound, and dispersant” was not within the range of 10:2:1:1:0.2:0.2:0.1, the fluoride removal efficiency of the material also decreased significantly. When the fluoride ion concentration in the fluorine-containing mine water was 3, 5, and 10 mg / L, and the dosage of the fluoride removal agent was 5, 6, and 8 parts per million, respectively, the fluoride ion concentration in the effluent was 2.6 mg / L, 3.7 mg / L, and 7.9 mg / L, respectively, and could not be reduced to below 1 mg / L.

[0070] Comparative Example 2:

[0071] The present comparative example provides a preparation method of a mine water defluorination agent, comprising the following steps: adding 200 g of aluminum chloride, 40 g of calcium chloride, 20 g of magnesium chloride, and 20 g of ferric chloride into 714 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of disodium ethylenediaminetetraacetate and 2 g of ethanol, continuing to stir for 5 min under heating at 40°C, and keeping warm for 1 h to obtain the defluorination agent after cooling.

[0072] The defluorination agent prepared in Comparative Example 2 was used to conduct defluorination tests on mine water containing different concentrations of fluoride ions according to the methods of Application Examples 1-3. The results showed that without adding a chelating agent, the material could not form a long-chain porous structure, and the specific surface area of the defluorination agent decreased to 75.7382 m 2 / g. The defluorination efficiency also decreased significantly. When the fluoride ion concentration in the mine water was 3, 5, and 10 mg / L, and the defluorination agent dosage was 5 parts per million, 6 parts per million, and 8 parts per million, respectively, the effluent fluoride ion concentrations were 1.6 mg / L, 2.9 mg / L, and 6.8 mg / L, respectively, all of which could not be reduced to below 1 mg / L.

[0073] Comparative Example 3:

[0074] The present comparative example provides a preparation method of a mine water defluorination agent, comprising the following steps: adding 200 g of aluminum chloride, 40 g of calcium chloride, 20 g of magnesium chloride, and 20 g of ferric chloride into 714 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of disodium ethylenediaminetetraacetate and 2 g of ethanol, continuing to stir for 5 min under heating at 40°C, and keeping warm for 1 h to obtain the defluorination agent after cooling.

[0075] The defluorination agent prepared in Comparative Example 3 was used to conduct defluorination tests on mine water containing different concentrations of fluoride ions according to the methods of Application Examples 1-3. The results showed that without adding a chelating agent, the material could not form a long-chain porous structure, and the specific surface area of the defluorination agent decreased to 75.7382 m 2 / g. The defluorination efficiency also decreased significantly. When the fluoride ion concentration in the mine water was 3, 5, and 10 mg / L, and the defluorination agent dosage was 5 parts per million, 6 parts per million, and 8 parts per million, respectively, the effluent fluoride ion concentrations were 1.6 mg / L, 2.9 mg / L, and 6.8 mg / L, respectively, all of which could not be reduced to below 1 mg / L.

[0076] Comparative Example 4:

[0077] The comparative example provides a preparation method of a mine water defluorination agent, including the following steps: adding 200 g of aluminum chloride, 40 g of calcium chloride, and 20 g of magnesium chloride in 730 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of nitrilotriacetic acid, 4 g of alpha-hydroxyacetic acid, and 2 g of sodium silicate, continuing to stir for 5 min under heating at 40°C, and keeping warm for 1 h, to obtain the defluorination agent after cooling.

[0078] The defluorination agent prepared in Comparative Example 4 is used to conduct defluorination tests on mine water containing different concentrations of fluoride ions according to the methods of Application Examples 1-3. The results show that, without the addition of the flocculation component iron salt, the material has poor sedimentation effect, it is difficult to achieve separation of mud and water, and the defluorination effect is also reduced. When the fluoride ion concentration in the mine water containing fluoride is 3, 5, and 10 mg / L, the defluorination agent is added in an amount of 5, 6, and 8 parts per million, respectively, and the effluent fluoride ion concentrations are 1.2, 2.1, and 4.6 mg / L, respectively, all of which cannot be reduced to below 1 mg / L.

[0079] Comparative Example 5:

[0080] The comparative example provides a preparation method of a mine water defluorination agent, including the following steps: adding 200 g of aluminum chloride, 40 g of calcium chloride, and 20 g of magnesium chloride in 730 mL of deionized water, stirring at 200 rpm for 5 min, then adding 4 g of nitrilotriacetic acid, 4 g of alpha-hydroxyacetic acid, and 2 g of sodium silicate, continuing to stir for 5 min under heating at 40°C, and keeping warm for 1 h, to obtain the defluorination agent after cooling.

[0081] The defluorination agent prepared in Comparative Example 4 is used to conduct defluorination tests on mine water containing different concentrations of fluoride ions according to the methods of Application Examples 1-3. The results show that, without the addition of the flocculation component iron salt, the material has poor sedimentation effect, it is difficult to achieve separation of mud and water, and the defluorination effect is also reduced. When the fluoride ion concentration in the mine water containing fluoride is 3, 5, and 10 mg / L, the defluorination agent is added in an amount of 5, 6, and 8 parts per million, respectively, and the effluent fluoride ion concentrations are 1.2, 2.1, and 4.6 mg / L, respectively, all of which cannot be reduced to below 1 mg / L.

[0082] It should be noted that, in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0083] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a mine water defluoridating agent, characterized in that: The steps include: Aluminum salt, calcium salt, magnesium salt and iron salt are added into water and stirred, and then a chelating agent, a hydroxycarboxylic acid compound and a dispersant are added, and the mixture is heated, stirred and dispersed, and kept warm to obtain a mine water defluoridating agent; the molar ratio of the aluminum salt, calcium salt, magnesium salt and iron salt is 1: (0.16-0.62): (0.09-0.36): (0.03-0.23).

2. The method for preparing a mine water defluoridating agent according to claim 1, wherein: Heat, stir and disperse, and keep warm: heat to 40-60℃, stir and disperse for 5-10 minutes, and keep warm for 1-2 hours.

3. The method for preparing a mine water defluoridating agent according to claim 1, wherein: The mass ratio of the chelating agent, the hydroxycarboxylic acid compound and the dispersant is 2:2:

1.

4. The method for preparing a mine water defluoridating agent according to claim 1, wherein: The mass ratio of aluminum salt, calcium salt, magnesium salt, iron salt, chelating agent, hydroxycarboxylic acid compound and dispersant is 10:2:1:1:0.2:0.2:0.

1.

5. The method for preparing a mine water defluoridating agent according to claim 1, wherein: The aluminum salt is at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate; The calcium salt is at least one of calcium chloride, calcium nitrate, calcium bicarbonate and calcium acetate; The magnesium salt is at least one of magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium acetate; The iron salt is at least one of ferric chloride, ferric sulfate, ferrous sulfate, ammonium ferric sulfate and ferric nitrate.

6. The method for preparing a mine water defluoridating agent according to claim 1, characterized in that: The chelating agent is at least one of sodium tripolyphosphate, EDTA sodium salt, nitrilotriacetic acid and hydroxyethylidene diphosphonic acid; the hydroxycarboxylic acid compound is at least one of α-hydroxyacetic acid, salicylic acid, citric acid and lactobionic acid.

7. The method for preparing a mine water defluoridating agent according to claim 1, characterized in that: The dispersant is at least one of ethanol, propanol, polyethylene glycol, sodium silicate, polymethacrylic acid, polyethyleneimine and sodium lauryl sulfate.

8. A mine water defluoridation agent, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the mine water defluoridation agent according to claim 8 in mine water defluoridation agents, characterized in that: The steps include: Add the defluoridating agent to the fluorine-containing mine water, stir and mix to form a colloidal state, then add the flocculant to make the colloid form alum flocs, and let the alum flocs settle to obtain a clear liquid after defluoridation.

10. Use of the mine water defluoridation agent according to claim 9, characterized in that: The flocculant is a polyacrylamide flocculant, the fluoride ion concentration in the fluoride-containing mine water is 1-10 mg / L; the dosage of the defluoridating agent is 0.05-0.1 wt %; the stirring speed is 200-300 rpm; the concentration of the polyacrylamide flocculant solution is 0.1 wt % and the dosage is 0.1-0.2 wt %.

Images