Composite flocculant, preparation method and application thereof

Abstract

The application provides a composite flocculant and a preparation method and application thereof, and belongs to the field of environmental protection.The composite flocculant is prepared from raw materials including the following components by mass percentage: coal-based solid waste 2-15%, iron-based coagulant 20-35%, aluminum-based coagulant 30-60%, and soluble salt 5-20%.The application uses coal-based solid waste as the skeleton of the composite flocculant, and has the advantages of green environmental protection and economy;the iron-based coagulant is added to form a multi-core multi-hydroxyl complex with iron as the core, so that the fluorine removal effect is improved;the aluminum-based flocculant and fluorine ions are added to form a stable AlF3 structure, so that the fluorine ion removal effect is improved;the soluble salt is added to improve the turbidity reduction effect while synergistically removing fluorine.The composite flocculant can make the concentration of fluorine ions in the treated mine water less than 1.0mg / L, and the turbidity less than 1.0NTU, and has the advantages of low cost and good turbidity reduction and fluorine removal effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental protection, and in particular to a composite flocculant, a preparation method and application thereof. BACKGROUND

[0002] Coal mine dewatering water is groundwater gushing water caused by human disturbance, and the water quality characteristics are mainly affected by geological conditions, coal seam characteristics and coal mining technology. In the process of coal mining, fluorine-containing minerals in the coal seam are dissolved into the soil layer through long-term physical weathering leaching and rainwater erosion, and then migrate and enrich into the groundwater, resulting in excessive fluorine ion concentration and turbidity in the coal mine dewatering water. The turbidity and fluorine ions contained in the coal mine dewatering water can cause serious damage to the quality of surface water and reduce its own purification capacity; they can also accumulate in the respiratory tract of aquatic animals such as fish, causing suffocation and death, and can also reach the human body through the food chain, causing fluorosis and fluorosis, and seriously endangering human health.

[0003] The commonly used methods for reducing turbidity and removing fluorine in coal mine dewatering water include chemical precipitation, coagulation sedimentation, adsorption, ion exchange, membrane separation and electrocoagulation. Compared with other methods for reducing turbidity and removing fluorine, the coagulation sedimentation method has the advantages of simple operation, no need to increase additional water treatment structures, large water treatment capacity and low treatment cost, and is one of the commonly used methods for reducing turbidity and removing fluorine.

[0004] However, traditional commercial flocculants such as polyaluminum chloride (PAC) and polyaluminum ferric chloride (PAFC) can only reduce the fluorine ion concentration to 1.7 mg / L, which cannot meet the requirement of 1.0 mg / L specified in the Surface Water Environmental Quality Standard (GB 3838-2002) for Class III surface water. In order to improve the fluorine removal efficiency, rare earth elements are used to prepare flocculants in the prior art, resulting in high cost of the flocculants, which is not suitable for practical application. At the same time, silicates are generally used as active components of the composite flocculants in the prior art, and with the rising price of silicates in recent years, the cost of the flocculants is also increasing.

[0005] Therefore, it is a technical problem to be solved in the field to develop a composite flocculant with low cost and good effect of reducing turbidity and removing fluorine. SUMMARY

[0006] The present application relates to the field of environmental protection, and in particular to a composite flocculant, a preparation method and application thereof.

[0007] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0008] The application provides a composite flocculant, which is prepared from raw materials including the following components in percentage by mass: 2-15% of coal-based solid waste, 20-35% of iron-based coagulant, 30-60% of aluminum-based coagulant, and 5-20% of soluble salt.

[0009] Preferably, the coal-based solid waste includes one or more of coal gangue, fly ash, carbide slag and smelting slag.

[0010] Preferably, the iron-based coagulant includes one or more of ferric nitrate nonahydrate, polymeric ferric chloride, polymeric ferric silicate, polymeric aluminum ferric chloride and polymeric aluminum ferric sulfate.

[0011] Preferably, the aluminum-based coagulant includes one or more of polyaluminum chloride, polyaluminum ferric silicate, aluminum chloride and aluminum sulfate.

[0012] Preferably, the soluble salt includes one or more of calcium chloride, calcium phosphate, magnesium chloride and zinc nitrate.

[0013] The application provides a preparation method of the composite flocculant.

[0014] (1) mixing the coal-based solid waste with water to obtain a suspension;

[0015] (2) mixing the iron-based coagulant with the suspension obtained in the step (1) and then performing a complex reaction to obtain a complex solution;

[0016] (3) mixing the complex solution obtained in the step (2) with the aluminum-based coagulant and the soluble salt in sequence and then performing a complex reaction to obtain the composite flocculant.

[0017] Preferably, the pH value of the complex reaction in the step (2) is 2-3.5.

[0018] Preferably, the temperature of the complex reaction in the step (3) is 60-70 DEG C, and the time of the complex reaction is 60-120 min.

[0019] The application provides an application of the composite flocculant or the composite flocculant prepared by the preparation method.

[0020] Preferably, the addition amount of the composite flocculant in the fluorine-containing high-turbidity mine dewatering water is (0.5-2.5) g / L.

[0021] The present application provides a kind of composite flocculants, by including the following components by mass percentage: coal-based solid waste 2-15%, iron coagulant 20-35%, aluminum coagulant 30-60%, and soluble salt 5-20% are prepared from raw materials.The present application uses coal-based solid waste as the skeleton of composite flocculants, realizes the reuse of waste, reduces the cost of composite flocculants, has the advantages of green environmental protection and economy;Add iron coagulant to form a multi-nuclear multi-hydroxyl complex with iron as the core, the hydroxyl in the complex can replace the fluoride ion well, lock the fluoride ion in the complex, thereby improving the defluorination effect;Add aluminum flocculant to form stable AlF3 structure with fluoride ions, improve the removal effect of fluoride ions;By adding soluble salt, not only can achieve synergistic defluorination but also can improve the flocculation of composite flocculants in mine water, improve the turbidity removal effect of composite flocculants.The experimental results show that the composite flocculants provided by the present application can quickly and stably remove fluoride ions and turbidity in mine dewatering water, so that the concentration of fluoride ions in the treated mine water is less than the limit value of 1.0 mg / L required by water body, and the turbidity is less than 1.0 NTU, with low cost and good defluorination effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the photo of the composite flocculants of the present application embodiment 1;

[0023] Figure 2 It is the SEM diagram of the composite flocculants of the present application embodiment 1;

[0024] Figure 3 It is the SEM diagram of the composite flocculants of the present application application example 3;

[0025] Figure 4 It is the XRD diagram of the composite flocculants of the present application embodiment 1 and the composite flocculants of the present application application example 3;

[0026] Figure 5 It is the turbidity removal rate curve of different dosages of the composite flocculants of the present application embodiment 1 in simulated coal mine dewatering water B;

[0027] Figure 6 It is the fluoride ion removal rate curve of different dosages of the composite flocculants of the present application embodiment 1 and commercial PAC flocculants in simulated coal mine dewatering water A;

[0028] Figure 7 It is the flow chart of the composite flocculants of the present application embodiment 1 treating fluorine-containing high-turbidity mine dewatering water. DETAILED DESCRIPTION

[0029] The application provides a composite flocculant, which is prepared from raw materials including coal-based solid waste 2-15%, iron-based coagulant 20-35%, aluminum-based coagulant 30-60% and soluble salt 5-20% by mass percentage.

[0030] The raw materials for preparing the composite flocculant according to the application include coal-based solid waste 2-15%, preferably 5-12%, more preferably 8-10%, and further preferably 8.5-9% by mass percentage. The content of coal-based solid waste is limited in the above range, so that the coal-based solid waste can serve as the skeleton of the composite flocculant, realize waste recycling and improve the fluorine ion removal efficiency.

[0031] In the application, the coal-based solid waste preferably includes one or more of coal gangue, fly ash, carbide slag and smelting slag. The types of coal-based solid waste are limited in the above range, so that the coal-based solid waste can fully react with the iron-based coagulant.

[0032] The raw materials for preparing the composite flocculant according to the application include iron-based coagulant 20-35%, preferably 25-35%, more preferably 30-35%, and further preferably 33-35% by mass percentage. The content of the iron-based coagulant is limited in the above range, so that the fluorine removal effect of the composite flocculant can be improved.

[0033] In the application, the iron-based coagulant preferably includes one or more of ferric nitrate nonahydrate, polymeric ferric chloride, polymeric ferric silicate, polymeric aluminum ferric chloride and polymeric aluminum ferric sulfate. The iron-based coagulant is limited to the above types, so that a multi-core polyhydroxy complex with iron as the core can be formed, the hydroxyl groups in the complex can well replace the fluorine ions and lock the fluorine ions in the complex, thereby achieving good fluorine removal effect.

[0034] In the application, the mass ratio of the coal-based solid waste to the iron-based coagulant is preferably 1:(2-5), and more preferably 1:(3-4). The mass ratio of the coal-based solid waste to the iron-based coagulant is limited in the above range, so that the coal-based solid waste can play a role of the skeleton of the flocculant and improve the fluorine removal efficiency of the flocculant. When the mass ratio of the coal-based solid waste to the iron-based coagulant is not in the above range, the fluorine ion removal efficiency will be reduced.

[0035] The raw materials for preparing the composite flocculant according to the application include aluminum-based coagulant 30-60%, preferably 35-55%, more preferably 40-50%, and further preferably 42-45% by mass percentage. The content of the aluminum-based coagulant is limited in the above range, so that the fluorine removal effect can be ensured while the cost is reduced.

[0036] In the present application, the aluminum coagulant preferably includes one or more of polyaluminum chloride, polyaluminum ferric silicate, aluminum chloride and aluminum sulfate. Defining the aluminum coagulant as the above-mentioned types in the present application can make the aluminum flocculant and fluoride ions form a stable AlF3 structure, and improve the defluorination effect of the flocculant.

[0037] In the present application, the mass ratio of the coal-based solid waste to the aluminum flocculant is preferably 1:(3-6), and more preferably 1:(4-5). Defining the mass ratio of the coal-based solid waste to the aluminum flocculant in the present application within the above-mentioned range can make the aluminum coagulant combine with fluoride ions to generate AlF3, ensure the defluorination effect while reducing the cost.

[0038] The raw materials for preparing the composite flocculant in the present application include soluble salt 5-20% by mass, preferably 8-17%, more preferably 10-15%, and further preferably 12-14%. Defining the content of the soluble salt within the above-mentioned range in the present application can synergistically remove fluoride and improve the sedimentation of the flocs in the mine water after the composite flocculant is added.

[0039] In the present application, the soluble salt preferably includes one or more of calcium chloride, calcium phosphate, magnesium chloride and zinc nitrate. Defining the soluble salt as the above-mentioned types in the present application can improve the defluorination and turbidity reduction effect of the flocculant.

[0040] In the present application, the mass ratio of the coal-based solid waste to the soluble salt is preferably 1:(1-2), and more preferably 1:(1.4-1.6). Defining the mass ratio of the coal-based solid waste to the soluble salt within the above-mentioned range in the present application can achieve synergistic defluorination and improve the sedimentation of the flocs in the mine water after the composite flocculant is added.

[0041] The present application realizes the reuse of waste, reduces the cost of the composite flocculant, and has the advantages of green environmental protection and economy by taking the coal-based solid waste as the skeleton of the composite flocculant. The addition of the iron coagulant can make the composite flocculant form a multi-core multi-hydroxyl complex with iron as the core. The hydroxyl groups in the complex can well replace the fluoride ions and lock the fluoride ions in the complex, thereby improving the defluorination effect. The addition of the aluminum flocculant can make the aluminum flocculant and the fluoride ions form a stable AlF3 stable structure, thereby improving the defluorination effect. The addition of the soluble salt can not only achieve synergistic defluorination but also improve the sedimentation of the flocs in the mine water after the composite flocculant is added, thereby improving the turbidity reduction effect of the composite flocculant.

[0042] The present application provides a preparation method of the composite flocculant as described in the above-mentioned scheme, which includes the following steps:

[0043] (1) mixing the coal-based solid waste with water to obtain a suspension;

[0044] (2) After mixing the iron-based coagulant with the suspension obtained in step (1), a complex reaction is carried out to obtain a complex solution;

[0045] (3) The complex solution obtained in step (2) is mixed with aluminum-based coagulant and soluble salt in sequence to carry out a composite reaction to obtain a composite flocculant.

[0046] This invention mixes coal-based solid waste with water to obtain a suspension.

[0047] In this invention, the mixing of the coal-based solid waste with water is preferably carried out under heating and stirring conditions. The heating is preferably water bath heating; the heating temperature is preferably 60–70°C; and the stirring speed is preferably 400–500 rpm. This invention, through heating and stirring, ensures more uniform heating of the coal-based solid waste during preparation, further accelerating the dissolution of soluble components in the coal-based solid waste and promoting subsequent reactions.

[0048] The present invention does not have a special limitation on the amount of water added, as long as it is sufficient to form a suspension of coal-based solid waste.

[0049] After obtaining the suspension, the present invention mixes the iron-based coagulant with the suspension and performs a composite reaction to obtain a complex solution.

[0050] In this invention, the mixing of the iron-based coagulant and the suspension is preferably carried out under conditions of heating and stirring. The heating is preferably water bath heating; the heating temperature is preferably 60–70°C; and the stirring speed is preferably 400–500 rpm.

[0051] In this invention, the iron-based coagulant is preferably further mixed with the suspension to adjust the pH value using a pH adjuster.

[0052] In this invention, the pH adjuster is preferably a hydrochloric acid solution or a sodium hydroxide solution; the mass concentration of the hydrochloric acid solution or sodium hydroxide solution is preferably 20% independently.

[0053] In this invention, the pH value for the composite reaction of the iron-based coagulant and the suspension is preferably 2 to 3.5. By limiting the pH value for the composite reaction of the iron-based coagulant and the suspension to the above range, this invention can generate hydroxyl complexes with iron as the core.

[0054] After obtaining the complex solution, the present invention mixes the complex solution with an aluminum-based coagulant and a soluble salt in sequence to carry out a composite reaction to obtain a composite flocculant.

[0055] In the present application, the mixing of the complex solution with the aluminum-based coagulant and the soluble salt is preferably carried out under the conditions of heating and stirring. The heating is preferably water bath heating; the temperature of the heating is preferably 60-70 DEG C; and the stirring speed is preferably 400-500 rpm.

[0056] In the present application, the temperature at which the complex solution is sequentially mixed with the aluminum-based coagulant and the soluble salt to carry out the complex reaction is preferably 60-70 DEG C, and more preferably 65-70 DEG C; and the time at which the complex solution is sequentially mixed with the aluminum-based coagulant and the soluble salt to carry out the complex reaction is preferably 60-120 min, and more preferably 90-120 min. The temperature and time at which the complex solution is sequentially mixed with the aluminum-based coagulant and the soluble salt to carry out the complex reaction in the present application are limited to the above ranges to ensure that the reaction is carried out sufficiently to form a multi-nuclear multi-hydroxyl complex mainly composed of iron, silicon, aluminum, calcium and / or magnesium, and / or zinc, and hydroxyl.

[0057] The present application preferably carries out drying and ball milling on the product of the complex reaction after the complex reaction of the complex solution with the aluminum-based coagulant and the soluble salt is completed to obtain a complex flocculant.

[0058] In the present application, the drying is preferably vacuum drying; and the time of the drying is preferably 10-12 h. The present application does not have special limitations on the temperature of the drying, and a temperature of 60 DEG C or below commonly used by those skilled in the art for vacuum drying can be used.

[0059] In the present application, the ball milling is preferably carried out in a ball mill. The present application does not have special limitations on the type of the ball mill, and a ball mill commonly used by those skilled in the art can be used.

[0060] In the present application, the speed of the ball milling is preferably 36-40 r / min. The present application does not have special limitations on the time of the ball milling, and the particle size of the product of the complex reaction can be ground to 30-100 mu m.

[0061] The present application improves the defluorination effect of the flocculant by mixing the coal-based solid waste with water to form a suspension, and then adding an iron-based coagulant to carry out a complex reaction to form a hydroxyl complex with iron as the core. The present application further improves the defluorination effect of the flocculant and improves the sedimentation of the floe in the mine water by adding an aluminum-based coagulant and a soluble salt to the complex solution to form a multi-nuclear multi-hydroxyl complex mainly composed of iron, silicon, aluminum, calcium and / or magnesium, and / or zinc, and hydroxyl, and using the soluble salt to synergistically remove fluorine.

[0062] The present application also provides the use of the complex flocculant described in the above technical solution or prepared by the preparation method described in the above technical solution in the dewatering of mine water containing fluorine and high turbidity.

[0063] In the present application, the adding amount of the composite flocculant in the fluorine-containing high-turbidity mine dewatering water is preferably (0.5-2.5) g / L, and more preferably 1 g / L. The present application limits the adding amount of the composite flocculant to the above range, which can ensure that the composite flocculant has good defluorination and turbidity reduction effects.

[0064] In the present application, the application of the composite flocculant in the fluorine-containing high-turbidity mine dewatering water preferably comprises the following steps:

[0065] The composite flocculant is added to the fluorine-containing high-turbidity mine dewatering water to be treated for primary stirring and mixing, and then the pH value is adjusted, followed by secondary stirring and standing and settling.

[0066] In the present application, the pH value of the fluorine-containing high-turbidity mine dewatering water to be treated is preferably 2.0-9.0; the initial concentration of fluoride ions in the fluorine-containing high-turbidity mine dewatering water to be treated is preferably ≤400 mg / L; and the turbidity of the fluorine-containing high-turbidity mine dewatering water to be treated is preferably ≤1000 NTU.

[0067] In the present application, the rotating speed of the primary stirring is preferably 100-300 r / min, and more preferably 200 r / min; and the time of the primary stirring is preferably 5-15 min. The composite flocculant and the fluorine-containing high-turbidity mine dewatering water can be quickly mixed through the primary stirring.

[0068] In the present application, the pH value is preferably adjusted to 7.0-8.0. The pH value is limited to the above range, which can improve the defluorination and turbidity reduction effects of the composite flocculant.

[0069] In the present application, the rotating speed of the secondary stirring is preferably 60-100 r / min; and the time of the secondary stirring is preferably 1-5 min. The rotating speed and the time of the secondary stirring are limited to the above range, which can promote the natural generation of flocs by the composite flocculant, avoid poor settling caused by floc breakage, and further improve the defluorination and turbidity reduction effects of the composite flocculant.

[0070] In the present application, the time of the standing and settling is preferably 10-20 min. The concentration and the turbidity of the fluorine in the fluorine-containing high-turbidity mine dewatering water are reduced through the standing and settling.

[0071] The composite flocculant is applied to the fluorine-containing high-turbidity mine dewatering water, which can quickly and stably remove the fluoride ions and the turbidity in the mine dewatering water, so that the concentration of the fluoride ions in the treated mine dewatering water is less than the limit value of 1.0 mg / L required by the water body, and the turbidity is less than 1.0 NTU.

[0072] In one application example of the present application, as shown in Figure 7 the flow of the composite flocculant in treating the fluorine-containing high-turbidity mine dewatering water is as follows:

[0073] The prepared composite flocculant is added into the fluorine-containing high-turbidity mine water to be treated, and stirred rapidly to mix uniformly, the pH value of the fluorine-containing high-turbidity mine water is adjusted to 7-8, and the flocculation is generated naturally under slow stirring, and the fluorine-containing high-turbidity mine water after treatment is settled.

[0074] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0075] Embodiment 1

[0076] The present application provides a composite flocculant, which is prepared from the following raw materials in percentage by mass: coal-based solid waste 8.7%, iron-based coagulant 34.8%, aluminum-based coagulant 43.5%, and soluble salt 13%;

[0077] The preparation method of the composite flocculant comprises the following steps:

[0078] (1) 2g of coal-based solid waste is mixed with water under the condition of water bath heating at 70℃ and stirring speed of 400rpm to obtain a suspension;

[0079] (2) 8g of iron-based coagulant is mixed with the suspension obtained in step (1) under the condition of water bath heating at 70℃ and stirring speed of 400rpm, and then a hydrochloric acid solution with mass concentration of 20% is used to adjust the pH value to 3 for complexation reaction to obtain a complex solution;

[0080] (3) the complex solution obtained in step (2) is sequentially mixed with 10g of aluminum-based coagulant and 3g of soluble salt under the condition of water bath heating at 70℃ and stirring speed of 400rpm for 2h, and then dried in a vacuum drying machine for 12h, and finally ground by a ball mill at a rotating speed of 36r / min to obtain a composite flocculant with particle size of 30-100nm;

[0081] The mass ratio of the coal-based solid waste to the iron-based coagulant is 1:4;

[0082] The mass ratio of the coal-based solid waste to the aluminum-based coagulant is 1:5;

[0083] The mass ratio of the coal-based solid waste to the soluble salt is 1:1.5.

[0084] The photo of the composite flocculant prepared in Embodiment 1 is shown in Figure 1 The photo of the composite flocculant prepared in Embodiment 1 is shown in Figure 1As can be seen, the composite flocculant is a yellow powder.

[0085] SEM image of the composite flocculant prepared in Example 1 is shown below. Figure 2 As shown, from Figure 2 It can be seen that the structure of the composite flocculant is similar to a network, with branches that interweave with each other, agglomerating the dispersed particles together to form a relatively compact network-like complex. This effectively increases the surface area of ​​the composite flocculant particles. The flocculant molecular chains form a three-dimensional network structure through such intermolecular association, which is beneficial to enhancing its adsorption bridging and sweeping capture performance, while also enhancing the phase transition ability of the flocs and improving flocculation efficiency.

[0086] Application Example 1

[0087] The composite flocculant prepared in Example 1 was added to the high-turbidity mine drainage water containing fluoride (denoted as simulated coal mine drainage water A) with an initial fluoride ion concentration of 10 mg / L, a turbidity of 400 NTU, and a pH of 5.96. The mixture was stirred for 15 min at a stirring speed of 200 rpm / min to rapidly mix the composite flocculant and the high-turbidity mine drainage water. At the same time, the pH of the high-turbidity mine drainage water was adjusted to 7.0. Then, the stirring speed was adjusted to 60 rpm / min and stirred for 5 min to promote the natural formation of flocs by the composite flocculant. Finally, stirring was stopped and the mixture was allowed to settle for 20 min.

[0088] During a five-day simulation test, it was determined that when the dosage of the composite flocculant in Example 1 of this invention was 0.86 g / L, the fluoride ion concentration in the treated effluent could reach below 1 mg / L, and the turbidity was below 1 NTU.

[0089] The SEM image of the composite flocculant flocs in Application Example 1 is shown below. Figure 3 As shown, from Figure 3 The results show that the particle size of the flocs increases after the reaction, indicating good settling performance. Furthermore, the blocky structure formed by the flocs can firmly lock fluoride ions within the flocs, achieving a high fluoride removal rate.

[0090] Application Example 2

[0091] The composite flocculant prepared in Example 1 was added to the high-turbidity mine drainage water containing fluoride (denoted as simulated coal mine drainage water B) with an initial fluoride ion concentration of 30 mg / L, a turbidity of 1000 NTU, and a pH of 6.17. The mixture was stirred for 12 min at a stirring speed of 180 r / min to rapidly mix the composite flocculant and the high-turbidity mine drainage water. At the same time, the pH of the high-turbidity mine drainage water was adjusted to 7.2. Then, the stirring speed was adjusted to 80 r / min and stirred for 2 min to promote the natural formation of flocs by the composite flocculant. Finally, stirring was stopped and the mixture was allowed to settle for 15 min.

[0092] During a five-day simulation test, it was determined that when the dosage of the composite flocculant in Example 1 of this invention was 2.25 g / L, the fluoride ion concentration in the treated effluent could reach below 1 mg / L, and the turbidity was below 1 NTU.

[0093] Application Example 3

[0094] The composite flocculant prepared in Example 1 was added to the high-turbidity mine drainage water containing fluoride (denoted as simulated coal mine drainage water C) with an initial fluoride ion concentration of 5 mg / L, a turbidity of 100 NTU, and a pH of 8.65. The mixture was stirred for 10 min at a stirring speed of 200 r / min to rapidly mix the composite flocculant and the high-turbidity mine drainage water. At the same time, the pH of the high-turbidity mine drainage water was adjusted to 7.1. Then, the stirring speed was adjusted to 60 r / min and stirred for 3 min to promote the natural formation of flocs by the composite flocculant. Finally, stirring was stopped and the mixture was allowed to settle for 10 min.

[0095] During a five-day simulation test, it was determined that when the dosage of the composite flocculant in Example 1 of this invention was 0.50 g / L, the fluoride ion concentration in the treated effluent could reach below 1 mg / L, and the turbidity was below 1 NTU.

[0096] Comparative Application Examples

[0097] Replace the composite flocculant in Application Example 1 with commercially available PAC flocculant, otherwise remain the same as in Application Example 1.

[0098] The XRD patterns of the composite flocculant in Example 1 and the composite flocculant flocs in Application Example 3 are shown below. Figure 4 As shown, from Figure 4 The data shows that the peaks at 2θ of 16.02°, 21.60°, and 33.65° of the composite flocculant belong to (Ca,Fe)2Al4Si5(OH). 18 (Zn,Fe)2Al4Si5(OH) 18 (Mg,Fe)₂Al₄Si₅(OH) 18 After the composite flocculant is placed in the drain water of a fluoride-containing, high-turbidity mine to obtain composite flocculant flocs, the hydroxyl groups of the iron-core hydroxyl complex undergo isomorphic exchange substitution to produce flocs such as (Ca,Fe)2Al4Si5(F). 18 (Zn,Fe)2Al4Si5(F) 18 (Mg,Fe)₂Al₄Si₅(F) 18 This proves that fluoride ions are fixed into the complex.

[0099] The curves showing the effect of different dosages of the composite flocculant on the turbidity removal rate in simulated coal mine drainage water B in Example 1 of this invention are shown below.Figure 5 As shown in Figure 5 It can be seen from the above that a small amount of composite flocculants can greatly reduce the turbidity of the fluorine-containing high-turbidity mine dewatering water, and when the addition amount of the composite flocculants is 1 g / L, the turbidity removal of the fluorine-containing high-turbidity mine dewatering water can reach 100%.

[0100] The curve graph of different addition amounts of the composite flocculants and commercial PAC flocculants in the simulated coal mine dewatering water A on the removal rate of fluorine ions in Embodiment 1 of the present application is shown in Figure 6 As shown in Figure 6 It can be seen from the above that when the addition amount of the composite flocculants is 1 g / L, the residual fluorine ion concentration of the fluorine-containing high-turbidity mine dewatering water can reach 0.63 mg / L, meeting the requirement of less than 1.0 mg / L limit value.

[0101] The composite flocculants obtained by the present application can quickly and stably remove the fluorine ions and turbidity in the fluorine-containing high-turbidity mine dewatering water after being added into the fluorine-containing high-turbidity mine dewatering water, and the fluorine ion concentration in the treated mine dewatering water is less than the 1.0 mg / L limit value required by the water body, and the turbidity is less than 1.0 NTU, which has low cost and good turbidity reduction and fluorine removal effect.

[0102] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. Application of a composite flocculant in fluorine-containing high-turbidity mine dewatering water, comprising the following steps: adding the composite flocculant into the fluorine-containing high-turbidity mine dewatering water to be treated, stirring and mixing once, adjusting the pH value, and then sequentially performing secondary stirring and standing and settling; the addition amount of the composite flocculant in the fluorine-containing high-turbidity mine dewatering water is (1-2.5) g / L; the composite flocculant is prepared from the following components by mass percentage: coal-based solid waste 2-15%, iron-based coagulant 20-35%, aluminum-based coagulant 30-60%, and soluble salt 5-20%; the mass ratio of the coal-based solid waste to the iron-based coagulant is 1:(2-5); the mass ratio of the coal-based solid waste to the aluminum-based coagulant is 1:(3-6); the mass ratio of the coal-based solid waste to the soluble salt is 1:(1-2); the coal-based solid waste comprises one or more of coal gangue, fly ash, and smelting slag; the iron-based coagulant comprises one or more of ferric nitrate nonahydrate, polymeric ferric chloride, polymeric aluminum ferric chloride, and polymeric aluminum ferric sulfate; the aluminum-based coagulant comprises one or more of polymeric aluminum chloride, aluminum chloride, and aluminum sulfate; the soluble salt comprises one or more of calcium chloride, calcium phosphate, magnesium chloride, and zinc nitrate; the preparation method of the composite flocculant comprises the following steps: (1) mixing the coal-based solid waste with water under heating and stirring to obtain a suspension; the heating temperature is 60-70℃; the stirring speed is 400-500 rpm; (2) mixing the iron-based coagulant with the suspension obtained in step (1) to perform a complex reaction to obtain a complex solution; (3) sequentially mixing the complex solution obtained in step (2) with the aluminum-based coagulant and the soluble salt to perform a complex reaction to obtain the composite flocculant.

2. Use according to claim 1, characterized in that: The pH value of the complex reaction in step (2) is 2-3.

5.

3. Use according to claim 1, characterized in that: The temperature of the complex reaction in step (3) is 60-70℃, and the complex reaction time is 60-120 min.

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