A method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants

Abstract

This invention discloses a method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants, comprising the following steps: S1, pretreatment; S2, pH adjustment; S3, coagulation reaction; S4, concentration treatment; S5, aeration treatment; and S6, filtration treatment. The advantages are: by establishing a precise correspondence between water quality parameters and pH through a quantitative formula specific to non-metallic minerals, adaptive pH adjustment is achieved, solving the pain points of traditional methods for treating colloidal tailings wastewater from non-metallic minerals, improving the flocculation efficiency of coagulants, and ensuring the stability of treatment results; through precise dosing and dynamic correction, reagent consumption is significantly reduced, greatly lowering treatment costs. This provides an efficient, economical, and precise solution for treating colloidal tailings wastewater from non-metallic mineral processing plants, and has broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of mineral processing, and more specifically to a method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants. Background Technology

[0002] Non-metallic mineral processing industries (such as quartz, fluorite, and feldspar beneficiation) generate large amounts of tailings wastewater during production. This wastewater is characterized by high concentrations of colloidal particles (particle size <1μm), trace amounts of heavy metals (lead, zinc, cadmium, etc.), and small amounts of residual organic flocculants. Due to the complex surface charge and high stability of colloidal particles, traditional treatment methods suffer from several drawbacks: First, excessive dosage of conventional coagulants easily leads to excessive sludge production, increasing treatment costs; second, sedimentation treatment cycles are long, colloidal particle settling efficiency is low, and there is a risk of tailings dam failure; third, treatment effectiveness is greatly affected by water quality fluctuations, and existing treatment methods are relatively crude, often using fixed parameter control, making precise management difficult, resulting in significant reagent waste and unstable effluent compliance rates.

[0003] Therefore, researching a treatment method that is tailored to the characteristics of non-metallic mineral colloidal wastewater, possesses adaptive control capabilities, and is highly efficient and cost-effective has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants. Addressing the pain points of traditional methods for treating colloidal tailings wastewater from non-metallic minerals, this invention proposes a quantitative formula specific to non-metallic minerals. By adjusting pH adaptively and adjusting the dosage of coagulants, the flocculation efficiency of coagulants is improved, ensuring stable treatment results and reducing treatment costs.

[0005] This invention is implemented by the following technical solution:

[0006] A method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants includes the following steps:

[0007] S1. Pretreatment: The tailings wastewater in the tailings pond is allowed to settle freely, causing the ore sand to settle. The tailings wastewater in the tailings pond comes from two sources: the first is for wet discharge, where the tailings wastewater from the concentrator is initially settled to allow the ore sand to settle, resulting in a difficult-to-settle colloidal water source with high mud content; the second is for dry discharge, where the tailings slurry from the concentrator is thickened and filtered, and the concentrated overflow water and filtrate water are combined to form the difficult-to-settle colloidal water source with high mud content.

[0008] S2, pH Adjustment: After sedimentation, the supernatant of the tailings wastewater overflows into the equalization tank to adjust the pH of the tailings wastewater to the initial preset pH value, which is 8.5±0.1. During the adjustment process, the wastewater is gently stirred at 100 rpm by the agitator in the equalization tank to ensure uniform pH. The adjustment time is ≤5 minutes. The core purpose of pH adjustment is to create a suitable acid-base environment for the coagulation reaction and improve the flocculation efficiency of the coagulant.

[0009] S3. Coagulation Reaction: The pH-adjusted tailings wastewater is fed into a coagulation reaction tank. Coagulant is added to the tank according to the preset initial dosage and mixed thoroughly. Water quality parameters are then monitored. Based on the monitored parameters, the pH of the tailings wastewater is adjusted using a pH adaptive adjustment method to the pH value corresponding to the fastest flocculation rate, promoting the flocculation of colloidal particles. The coagulant includes ferrous sulfate and polyacrylamide, wherein ferrous sulfate serves as the main coagulant, providing Fe... 2+ Hydrolysis forms polynuclear hydroxy complexes, which neutralize the surface charge of colloidal particles; polyacrylamide, as a coagulant aid, promotes floc growth through adsorption bridging, and the two work synergistically to improve flocculation efficiency.

[0010] S4. Concentration treatment: The tailings wastewater after coagulation reaction is introduced into a thickener for concentration treatment. The underflow of the thickener is returned to the tailings dam to participate in wastewater treatment again. It is then introduced into a sedimentation device to allow the flocs to settle and separate.

[0011] S5. Aeration Treatment: The overflow water from the thickener enters the aeration tank, where sodium sulfide is added to remove residual heavy metal ions. Aeration oxidizes the organic matter in the wastewater, reducing the concentration of pollutants such as COD and ammonia nitrogen. It also further removes residual fine suspended particles and colloidal substances, improving the stability of the effluent quality. The amount of sodium sulfide added is determined based on the heavy metal ion content in the wastewater entering the aeration tank, which is a standard technique in this industry. Since the amount added is small, a fixed amount can be added.

[0012] S6. Filtration treatment: The effluent after aeration treatment enters a multi-media filter for filtration treatment and then enters a high-level water tank for mineral processing.

[0013] Furthermore, in S3, the adaptive adjustment, the water quality parameters include Zeta potential, initial pH value, dynamic viscosity, and colloidal particle size, which are collected in real time by an online monitoring sensor matrix at a frequency of once per second. Specifically, the Zeta potential sensor accuracy is ≤ ±0.1 mV, the pH sensor accuracy is ≤ ±0.01 mPa·s, the dynamic viscosity sensor accuracy is ≤ ±0.001 mPa·s, and the colloidal particle size sensor has a measurement range of 0.01-10 μm and an accuracy of ≤ ±2%. The sensor matrix is ​​installed at the inlet, middle, and outlet of the equalization tank, and the average value is collected synchronously at these three points. Calibration is performed every 24 hours using standard solutions. Zeta potential calibration uses standard latex particles (0.5 μm particle size, Zeta potential -30 mV ± 1 mV), and pH calibration uses standard buffer solutions at pH 4.00, 6.86, and 9.18 to ensure the accuracy of the monitoring data.

[0014] Furthermore, in the S3 coagulation reaction, the pH adaptive adjustment method includes the following steps:

[0015] S31: Set the colloidal flocculation rate The target range is 0.6 1.0 μm / s;

[0016] S32: Based on real-time collected water quality parameters and initial dosage, the colloidal flocculation rate is calculated using a non-metallic mineral-specific quantitative formula. The range of Zeta potentials corresponding to the target range is set as the target range of Zeta potentials.

[0017] S33: For quartz, fluorite, and feldspar mines, tailings wastewater was collected and parameters such as colloidal concentration, colloidal particle size, and dynamic viscosity were fixed in a laboratory environment. The pH of the wastewater was adjusted according to a gradient of 0.5 units from pH 4.0 to 9.0. After standing for 5 minutes at each gradient, the Zeta potential was measured three times and the average value was taken to obtain the corresponding "pH-Zeta potential" relationship for different minerals. The core correspondence between pH and Zeta potential for each mineral is shown in Table 1.

[0018] Table 1. Core Correspondence between pH and Zeta Potential for Various Mineral Types

[0019]

[0020] Based on the pH-Zeta potential curve obtained through experimental calibration, determine the pH range that matches the target range of the Zeta potential and set it as the target pH range;

[0021] S34: Based on the difference between the initial pH value of the wastewater and the target pH range, and in conjunction with the wastewater flow rate, calculate the theoretical addition flow rate of hydrochloric acid or sodium hydroxide, and accurately add it through an automatic dosing pump.

[0022] S35: Real-time monitoring of the actual pH and Zeta potential values ​​of the adjusted wastewater, and calculation of the actual colloidal flocculation rate using a non-metallic mineral-specific quantitative formula. If the actual colloidal flocculation rate If the deviation from the target range for colloidal flocculation rate is ±5%, the dosage should be dynamically adjusted.

[0023] Furthermore, in step S3, the preset initial dosage is 200-250 g / m³ of ferrous sulfate. 3 Polyacrylamide 10-25g / m 3 .

[0024] Furthermore, in step S32, the specific quantitative formula for non-metallic minerals is:

[0025]

[0026] In the above formula:

[0027] This refers to the colloid flocculation rate;

[0028] The coefficients are specific to non-metallic minerals, where: k=0.085 for quartz, k=0.092 for fluorite, and k=0.078 for feldspar. The k value is determined by the following method: taking tailings wastewater of the corresponding mineral, fixing the coagulant dosage ratio, colloidal particle size, and dynamic viscosity, adjusting the pH to 7.0, measuring the colloidal flocculation rate at different coagulant concentrations, substituting into the formula to deduce the k value, repeating each experiment 5 times, and taking the average as the final coefficient; when extending to other non-metallic minerals, the specific k value can be determined under the same experimental conditions to ensure the formula's compatibility.

[0029] [Fe 2+ [This refers to the effective concentration of ferrous sulfate, specifically the Fe3+ concentration in the ferrous sulfate added to wastewater that can participate in colloidal flocculation reactions.] 2+ The actual concentration (unit: g / L) is calculated as follows:

[0030]

[0031] in,

[0032] The mass of ferrous sulfate heptahydrate added (unit: g). For Fe 2+ The molar mass is 55.85 g / mol. V is the molar mass of ferrous sulfate heptahydrate (278.02 g / mol), and V is the wastewater treatment volume (unit: L).

[0033] [PAM] refers to the concentration of polyacrylamide, specifically the actual mass concentration (unit: g / L) of polyacrylamide (anionic, molecular weight 8 million-12 million) added to the wastewater.

[0034] The zeta potential of tailings wastewater;

[0035] The dynamic viscosity of tailings wastewater;

[0036] d c The colloidal particle size of the tailings wastewater.

[0037] This quantitative formula is based on the flocculation kinetics of non-metallic mineral colloidal wastewater and was calibrated through single-factor variable experiments and multiple linear regression analysis. The experimental conditions were: temperature 20±2℃, colloidal concentration 100-300mg / L, pH 4.0-9.0. Three parallel experiments were set for each set of parameters. After removing outliers, the mean was used to fit the formula parameters. The exponents 0.7 and 0.3 correspond to the influence weights of ferrous sulfate and polyacrylamide on the flocculation rate, respectively, and are determined by the coagulant action mechanism and experimental data fitting. The exponent 0.5 reflects the influence of colloidal particle size on collision probability, which is consistent with the colloidal sedimentation kinetics theory. The constant term 25 is the baseline value calibrated by the experiment, used to offset the influence of the negative value of the Zeta potential on the calculation results and ensure that the flocculation rate is a positive and reasonable value.

[0038] Furthermore, in S35, the specific method for dynamically adjusting the dosage is as follows:

[0039] If the actual colloidal flocculation rate If the concentration is 5% below the target lower limit, add sodium hydroxide at 5%-8% of the current dosage or reduce the hydrochloric acid dosage until the actual colloidal flocculation rate is reached. ≥ Target lower limit of colloidal flocculation rate;

[0040] If the actual colloidal flocculation rate If the concentration exceeds the target upper limit by 5%, add hydrochloric acid at 5%-8% of the current dosage or reduce the sodium hydroxide dosage until the actual colloidal flocculation rate is reached. ≤Target upper limit of colloidal flocculation rate;

[0041] If the floc particle size at the outlet of the coagulation reaction tank is <100μm, increase the dosage of ferrous sulfate by 5%-12% and the dosage of polyacrylamide by 3%-8%.

[0042] If the floc particle size at the outlet of the coagulation reaction tank is >500μm, reduce the dosage of ferrous sulfate by 5%-12% and the dosage of polyacrylamide by 3%-8%.

[0043] Furthermore, in S5, the aeration treatment, the aeration tank is equipped with 3-5 aeration zones along the water flow direction, and the bubble diameter generated by each aeration zone along the water flow direction gradually decreases from 1 mm to 0.2 mm; the aeration tank uses microporous aeration heads made of polytetrafluoroethylene, with pore sizes corresponding to bubble diameters of 50-200 μm, and the aeration head arrangement density of each aeration zone is 2-3 heads / m. 2 The gas flow rate is sequentially increased along the direction of water flow; the gas flow rate distribution ratio is as follows: the first stage (1mm bubble) accounts for 35% of the total flow rate, the second stage (0.7mm bubble) accounts for 30%, the third stage (0.4mm bubble) accounts for 20%, and the fourth stage (0.2mm bubble, to be added as needed) accounts for 15%, which is precisely controlled by the flow regulating valve.

[0044] Furthermore, in the S6 filtration process, the multi-media filter is provided with a quartz sand layer, an activated carbon layer, and a zeolite filter layer in sequence along the water flow direction. The thickness ratio of the quartz sand layer, activated carbon layer, and zeolite filter layer is 1:2:1, specifically: 5cm quartz sand, 10cm activated carbon, and 5cm zeolite. Among them, the quartz sand plays a role in intercepting large flocculent particles, the activated carbon enhances the adsorption of heavy metals, and the zeolite further removes residual colloids and trace heavy metals. The three work together to improve the filtration effect.

[0045] Advantages of this invention:

[0046] By establishing a precise correlation between water quality parameters and pH using a quantitative formula specific to non-metallic minerals, adaptive pH adjustment was achieved. This addresses the pain points of traditional methods for treating colloidal tailings wastewater from non-metallic minerals, improves the flocculation efficiency of coagulants, and ensures the stability of treatment results. Through precise dosing and dynamic correction, reagent consumption is significantly reduced, greatly lowering treatment costs. This provides an efficient, economical, and precise solution for treating colloidal tailings wastewater from non-metallic mineral processing plants, with broad application prospects. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] The initial parameters of the quartz ore colloidal tailings wastewater produced by a certain enterprise are as follows:

[0050] Initial pH = 6.0, Zeta potential = -20.1 mV, dynamic viscosity = 0.00102 mPa·s, colloidal particle size = 0.5 μm, COD concentration = 85 mg / L, ammonia nitrogen concentration = 12 mg / L, lead ion concentration = 0.3 mg / L, zinc ion concentration = 0.5 mg / L, turbidity = 320 NTU.

[0051] The wastewater is treated using the method of the present invention, and the treatment process is as follows:

[0052] S1. Pretreatment: Free settling for 2 hours to remove mineral sand with a particle size >1μm, and the supernatant enters the equalization tank.

[0053] S2. pH adjustment: The initial pH was adjusted to 8.5 by adding 10% sodium hydroxide solution. The stirring speed was 100 rpm and the adjustment time was 4 min. After adjustment, the pH of the wastewater was stable at 8.5±0.03, which provided a basis for subsequent adaptive adjustment.

[0054] S3. Coagulation reaction: For quartz ore, the specific synergistic coefficient k = 0.085, and the initial dosage is: ferrous sulfate heptahydrate dosage is 200 g / m³. 3 The calculation yielded [Fe 2+ =0.0162 g / L, the dosage of anionic polyacrylamide (molecular weight 10 million) is 20 g / m 3 The calculated value is [PAM] = 0.002 g / L.

[0055] During pH adaptive adjustment: setting the colloidal flocculation rate The target range is 0.6-1.0 μm / s. Substituting the values ​​into the specific quantitative formula, the target range for the Zeta potential is calculated to be -9.0 to -11.5 mV. Based on the pH-Zeta potential correspondence for quartz in Table 1, the target pH range is determined to be 8.0 to 8.3. Therefore, hydrochloric acid needs to be added to adjust the pH from 8.5 to 8.0-8.3. The final pH stabilizes at 8.2, with an actual Zeta potential of -10.8 mV. The actual colloidal flocculation rate is then calculated. =0.78μm / s (within the target range). The floc particle size at the outlet of the coagulation reaction tank is 310μm, with uniform particle size distribution, and no adjustment of the coagulant dosage is required.

[0056] S4. Thickening treatment: After thickening, the underflow concentration is 31%, which is returned to the tailings pond for recycling. The overflow water is clear and enters the aeration tank.

[0057] S5. Aeration treatment: The fixed dosage of sodium sulfide is 5 g / m³. 3The bubble diameters in the three aeration zones are 1mm, 0.7mm, and 0.4mm respectively, the gas flow distribution ratio is 35%:30%:25%, the total air-to-water ratio is 8:1, and the aeration time is 1.5h.

[0058] S6. Filtration treatment: filtered through a multi-media filter at a filtration rate of 2 m / h.

[0059] The processing results are as follows:

[0060] The effluent had the following characteristics: pH 7.9, turbidity 4.9 NTU, COD concentration 17 mg / L, ammonia nitrogen concentration 1.7 mg / L, lead ion concentration 0.009 mg / L, zinc ion concentration 0.018 mg / L, Zeta potential -3.2 mV, colloidal particle removal rate 98.6%, heavy metal removal rate ≥97%, COD removal rate 80.0%, and ammonia nitrogen removal rate 85.8%. The treatment cycle was 4.4 h, and the coagulant consumption was 22 g / m³. 3 Wastewater and sludge production amount is 0.78 kg / m³. 3 All indicators of the wastewater and effluent meet the Class I standard of the "Discharge Standard of Pollutants for Mineral Processing Wastewater" (GB 25461-2010) and can be directly reused in the mineral processing stage.

[0061] Example 2

[0062] The initial parameters of the wastewater from the colloidal tailings of a certain enterprise are as follows:

[0063] Initial pH = 7.2, Zeta potential = -15.2 mV, dynamic viscosity = 0.00105 mPa·s, colloidal particle size = 0.4 μm, COD concentration = 92 mg / L, ammonia nitrogen concentration = 13 mg / L, cadmium ion concentration = 0.2 mg / L, zinc ion concentration = 0.6 mg / L, turbidity = 350 NTU.

[0064] The wastewater is treated using the method of the present invention, and the treatment process is as follows:

[0065] S1. Pretreatment: Free settling for 2 hours to remove mineral sand with a particle size >1μm, and the supernatant enters the equalization tank.

[0066] S2. pH adjustment: The initial pH was adjusted to 8.5 by adding 10% sodium hydroxide solution, with a stirring speed of 100 rpm and an adjustment time of 4.5 min. After adjustment, the pH of the wastewater stabilized at 8.5±0.02, providing a basis for subsequent adaptive adjustment.

[0067] S3. Coagulation reaction: For fluorite ore, the specific synergistic coefficient k = 0.092, and the initial dosage is: ferrous sulfate heptahydrate dosage is 210 g / m³. 3 The calculation yielded [Fe2+ =0.017 g / L, the dosage of anionic polyacrylamide (molecular weight 10 million) is 22 g / m 3 The calculated value is [PAM] = 0.0022 g / L.

[0068] During pH adaptive adjustment: setting the colloidal flocculation rate The target range is 0.6-1.0 μm / s. Substituting the values ​​into the specific quantitative formula, the target range of the Zeta potential is calculated to be -7.5 to -9.0 mV. Combining this with the pH-Zeta potential correspondence for fluorite ore in Table 1, the target pH range is determined to be 8.7 to 9.0. Therefore, 10% sodium hydroxide needs to be added to adjust the pH from 8.5 to 8.7-9.0. The final pH stabilizes at 8.8, and the actual Zeta potential is -8.0 mV. The actual colloidal flocculation rate is then calculated. =0.85μm / s (within the target range). The floc particle size at the outlet of the coagulation reaction tank is 360μm, with uniform particle size distribution, and no adjustment of the coagulant dosage is required.

[0069] S4. Thickening treatment: After thickening, the underflow concentration is 33%, which is returned to the tailings pond for recycling. The overflow water is clear and enters the aeration tank.

[0070] S5. Aeration treatment: The fixed dosage of sodium sulfide is 5.5 g / m³. 3 The bubble diameters in the three aeration zones are 1mm, 0.7mm, and 0.4mm respectively, the gas flow distribution ratio is 35%:30%:25%, the total air-to-water ratio is 8:1, and the aeration time is 1.5h.

[0071] S6. Filtration treatment: filtered through a multi-media filter at a filtration rate of 2 m / h.

[0072] The processing results are as follows:

[0073] The effluent had the following characteristics: pH 8.0, turbidity 4.5 NTU, COD concentration 15 mg / L, ammonia nitrogen concentration 1.5 mg / L, cadmium ion concentration 0.007 mg / L, zinc ion concentration 0.017 mg / L, Zeta potential -3.0 mV, colloidal particle removal rate 98.9%, heavy metal removal rate ≥96.5%, COD removal rate 83.7%, and ammonia nitrogen removal rate 88.5%. The treatment cycle was 4.2 hours, and the coagulant consumption was 23.2 g / m³. 3 Wastewater and sludge production amount is 0.73 kg / m³. 3 All indicators of the wastewater and effluent meet the Class I standard of the "Discharge Standard of Pollutants for Mineral Processing Wastewater" (GB 25461-2010) and can be directly reused in the mineral processing stage.

[0074] Example 3

[0075] The initial parameters of the wastewater from the colloidal tailings of a certain enterprise are as follows:

[0076] Initial pH = 7.0, Zeta potential = -20.7 mV, dynamic viscosity = 0.00103 mPa·s, colloidal particle size = 0.6 μm, COD concentration = 88 mg / L, ammonia nitrogen concentration = 14 mg / L, lead ion concentration = 0.25 mg / L, cadmium ion concentration = 0.15 mg / L, turbidity = 330 NTU.

[0077] The wastewater is treated using the method of the present invention, and the treatment process is as follows:

[0078] S1. Pretreatment: Free settling for 2 hours to remove mineral sand with a particle size >1μm, and the supernatant enters the equalization tank.

[0079] S2. pH adjustment: The initial pH was adjusted to 8.5 by adding 10% sodium hydroxide solution. The stirring speed was 100 rpm and the adjustment time was 4 min. After adjustment, the pH of the wastewater was stable at 8.5±0.03, which provided a basis for subsequent adaptive adjustment.

[0080] S3. Coagulation reaction: For feldspar ore, the specific synergistic coefficient k = 0.078, and the initial dosage is: ferrous sulfate heptahydrate dosage is 220 g / m³. 3 The calculation yielded [Fe 2+ =0.0178 g / L, the dosage of anionic polyacrylamide (molecular weight 10 million) is 23 g / m 3 The calculated value is [PAM] = 0.0023 g / L.

[0081] During pH adaptive adjustment: setting the colloidal flocculation rate The target range is 0.6-1.0 μm / s. Substituting the values ​​into the specific quantitative formula, the target range for the Zeta potential is calculated to be -14.0 to -16.5 mV. Combining this with the pH-Zeta potential correspondence for feldspar ore in Table 1, the target pH range is determined to be 8.4 to 8.8. Therefore, no additional reagents are needed to adjust the pH. The actual Zeta potential was measured to be -14.6 mV, and the actual colloidal flocculation rate was calculated. =0.72μm / s (within the target range). The floc particle size at the outlet of the coagulation reaction tank is 300μm, with uniform particle size distribution, and no adjustment of the coagulant dosage is required.

[0082] S4. Thickening treatment: After thickening, the underflow concentration is 28%, which is returned to the tailings pond for recycling. The overflow water is clear and enters the aeration tank.

[0083] S5. Aeration treatment: The fixed dosage of sodium sulfide is 6g / h. The bubble diameters of the three aeration zones are 1mm, 0.7mm and 0.4mm respectively. The gas flow distribution ratio is 35%:30%:25%, the total air-water ratio is 8:1, and the aeration time is 1.5h.

[0084] S6. Filtration treatment: filtered through a multi-media filter at a filtration rate of 2 m / h.

[0085] The processing results are as follows:

[0086] The effluent had the following characteristics: pH 7.9, turbidity 5.5 NTU, COD concentration 17 mg / L, ammonia nitrogen concentration 1.9 mg / L, lead ion concentration 0.009 mg / L, cadmium ion concentration 0.007 mg / L, Zeta potential -3.8 mV, colloidal particle removal rate 98.4%, heavy metal removal rate ≥95.5%, COD removal rate 80.7%, and ammonia nitrogen removal rate 86.4%. The treatment cycle was 4.6 hours, and the coagulant consumption was 24.3 g / m³. 3 Wastewater and sludge production amount is 0.82 kg / m³. 3 The wastewater meets the Class I standard of the "Discharge Standard of Pollutants for Mineral Processing Wastewater" (GB25461-2010) and can be reused in the mineral processing stage.

[0087] Comparative Example 1

[0088] For the treatment of colloidal tailings wastewater from fluorite ore in Example 1, this comparative example uses a conventional ferrous sulfate and polyacrylamide coagulation system. There is no coarse pH adjustment step within the 8.4-8.6 range; the pH is directly fixed at 7.0 without adaptive adjustment, and the dosage is fixed, with ferrous sulfate heptahydrate at 300 g / m³. 3 Polyacrylamide is 30g / m 3 The aeration was performed without gradient, using ordinary aeration heads with a bubble diameter of 1-2 mm and an aeration time of 2 hours; a single quartz sand filter was used for filtration with a filter layer thickness of 20 cm. All other conditions were consistent with those in Example 1.

[0089] The treatment results of this comparative example are as follows: effluent pH = 6.8, turbidity = 28 NTU, COD concentration = 45 mg / L, ammonia nitrogen concentration = 5.2 mg / L, lead ion concentration = 0.08 mg / L, zinc ion concentration = 0.12 mg / L, colloidal particle removal rate = 90.5%, heavy metal removal rate = 76%, COD removal rate = 46.5%, and ammonia nitrogen removal rate = 56.7%. The treatment cycle is 6.5 hours, and the unit consumption of coagulant is 33 g / m³. 3 Wastewater and sludge production amount is 1.5 kg / m³. 3 The wastewater, with its turbidity and COD levels not meeting the first-class standard, cannot be directly reused in the mineral processing stage.

[0090] As can be seen from the implementation of Example 1 and Comparative Example 1, compared with traditional methods, the colloid removal rate and metal removal rate of the present invention are significantly improved, and the treated wastewater can stably reach the first-class standard. By calculating the target pH value and coagulant dosage through a dedicated quantitative formula, precise dosing is achieved, reducing reagent consumption by 30%-40% compared with traditional methods and avoiding reagent waste. Under conditions of fluctuating water quality, the effluent compliance rate is ≥99.5%, and the anti-interference ability is significantly better than the existing schemes, requiring no frequent manual intervention and exhibiting strong stability. The moisture content of the treated sludge is ≤50%, which is significantly lower than that of traditional methods, reducing sludge disposal costs by more than 30%.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for efficiently treating colloidal tailings wastewater from non-metallic mineral processing plants, characterized in that, Includes the following steps: S1. Pretreatment: The tailings wastewater in the tailings pond is allowed to settle freely, causing the mineral sand to settle. S2, pH adjustment: After sedimentation, the supernatant of the tailings wastewater overflows into the equalization tank to adjust the pH of the tailings wastewater to the initial preset pH value. S3. Coagulation reaction: The pH-adjusted tailings wastewater is fed into the coagulation reaction tank. Coagulant is added to the coagulation reaction tank according to the preset initial dosage and mixed evenly. Then, water quality parameters are monitored. Based on the monitored water quality parameters, the pH of the tailings wastewater is adjusted by a pH adaptive adjustment method to promote the flocculation of colloidal particles. The coagulant includes ferrous sulfate and polyacrylamide. S4. Concentration treatment: The tailings wastewater after coagulation reaction is introduced into a thickener for concentration treatment, and the underflow of the thickener is returned to the tailings dam to participate in wastewater treatment again. S5. Aeration treatment: The overflow water from the thickener enters the aeration tank, where sodium sulfide is added to remove residual heavy metal ions. Aeration oxidizes the organic matter in the wastewater to reduce the concentration of COD and ammonia nitrogen in the water. At the same time, it further removes residual fine suspended particles and colloidal substances in the water, improving the stability of the effluent quality. S6. Filtration treatment: The effluent after aeration treatment enters a multi-media filter for filtration treatment and then enters a high-level water tank for mineral processing. In the S3 coagulation reaction, the pH adaptive adjustment method includes the following steps: S31: Set the colloidal flocculation rate The target range is 0.6 1.0 μm / s; S32: Based on real-time collected water quality parameters and initial dosage, the colloidal flocculation rate is calculated using a non-metallic mineral-specific quantitative formula. The range of Zeta potentials corresponding to the target range is set as the target range of Zeta potentials. S33: Based on the "pH-Zeta potential" corresponding curve obtained through experimental calibration, determine the pH range that matches the target range of the Zeta potential, and set it as the target pH range; S34: Based on the difference between the initial pH value of the wastewater and the target pH range, and in conjunction with the wastewater flow rate, calculate the theoretical addition flow rate of hydrochloric acid or sodium hydroxide, and accurately add it through an automatic dosing pump. S35: Real-time monitoring of the actual pH and Zeta potential values ​​of the adjusted wastewater, and calculation of the actual colloidal flocculation rate using a non-metallic mineral-specific quantitative formula. If the actual colloidal flocculation rate If the deviation from the target range for colloidal flocculation rate is ±5%, the dosage should be dynamically adjusted.

2. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In the S3 adaptive adjustment, the water quality parameters include zeta potential, initial pH value, dynamic viscosity, and colloidal particle size.

3. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In step S3, the preset initial dosage is 200-250 g / m³ of ferrous sulfate. 3 Polyacrylamide 10-25g / m 3 .

4. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In step S32, the specific quantitative formula for non-metallic minerals is: In the above formula: This refers to the colloid flocculation rate; For non-metallic minerals, k = 0.085 for quartz, k = 0.092 for fluorite, and k = 0.078 for feldspar. [Fe 2+ [This refers to the effective concentration of ferrous sulfate;] [PAM] represents the concentration of polyacrylamide; The zeta potential of tailings wastewater; The dynamic viscosity of tailings wastewater; d c The colloidal particle size of the tailings wastewater.

5. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In S35, the specific method for dynamically adjusting the dosage is as follows: If the actual colloidal flocculation rate If the concentration is 5% below the target lower limit, add sodium hydroxide at 5%-8% of the current dosage or reduce the hydrochloric acid dosage until the actual colloidal flocculation rate is reached. ≥ Target lower limit of colloidal flocculation rate; If the actual colloidal flocculation rate If the concentration exceeds the target upper limit by 5%, add hydrochloric acid at 5%-8% of the current dosage or reduce the sodium hydroxide dosage until the actual colloidal flocculation rate is reached. ≤Target upper limit of colloidal flocculation rate; If the floc particle size at the outlet of the coagulation reaction tank is <100μm, increase the dosage of ferrous sulfate by 5%-12% and the dosage of polyacrylamide by 3%-8%. If the floc particle size at the outlet of the coagulation reaction tank is >500μm, reduce the dosage of ferrous sulfate by 5%-12% and the dosage of polyacrylamide by 3%-8%.

6. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In the S5 aeration treatment, the aeration tank is equipped with 3-5 aeration zones along the water flow direction, and the diameter of the bubbles generated by each aeration zone along the water flow direction gradually decreases from 1 mm to 0.2 mm.

7. The method for efficiently treating colloidal tailings wastewater from a non-metallic mineral processing plant according to claim 1, characterized in that, In the S6 filtration process, the multi-media filter is provided with a quartz sand layer, an activated carbon layer and a zeolite filter layer in sequence along the water flow direction, and the thickness ratio of the quartz sand layer, the activated carbon layer and the zeolite filter layer is 1:2:1.

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