Method for treating ardealite leachate by utilizing serpentine minerals

Abstract

The invention discloses a method for treating ardealite leachate by utilizing serpentine minerals, and belongs to the technical field of fluorine-phosphorus wastewater treatment. The method comprises the following steps: activating serpentine minerals, mixing the serpentine minerals with ardealite leachate to carry out fluorite phosphorizing reaction, and after the reaction is completed, carrying out solid-liquid separation to obtain defluorinated phosphorus leachate and fluorite slag. According to the method, a serpentine layered silicate structure, surface active groups, unsaturated Si-O-Si bonds and Mg < 2 + > sites are utilized to selectively adsorb fluorine ions and phosphate radicals in the ardealite leachate and release OH <-> and Mg < 2 + >, so that the pH value of the ardealite leachate is increased, the fluorine ions and the phosphate radicals are mineralized into crystals such as magnesium fluoride and magnesium phosphate, and the phosphogypsum leachate can be recycled. Therefore, fluorine ions and phosphate radicals in the ardealite leachate are synchronously reduced. The method has the advantages of easily available raw materials, mild reaction conditions and simple operation, treats waste with waste, and promotes the green sustainable development of the industry.

Description

Technical Field

[0001] This invention relates to a phosphogypsum leachate, and more particularly to a method for treating phosphogypsum leachate using serpentine minerals, belonging to the field of fluorophosphorus wastewater treatment technology. Background Technology

[0002] Leachate from phosphogypsum is an acidic wastewater formed during the open-air storage or disposal of phosphogypsum, influenced by both natural factors and the characteristics of the phosphogypsum pile. Its formation mechanism primarily includes: precipitation erosion causing soluble substances (such as phosphates and fluorides) to dissolve from the pile surface and collect with runoff; consolidation and settling due to the pile's own weight during long-term storage, squeezing out internal pore water; and the mixing of supernatant and rainwater generated during the transport and sedimentation of the phosphogypsum slurry, further exacerbating leachate formation. This type of wastewater is typically highly acidic (low pH) and contains high concentrations of pollutants such as phosphates, fluorides, and sulfates. Fluorides and heavy metals are bioaccumulative and can enter the food chain through the soil-crop system, threatening human health. If discharged directly without effective treatment, leachate can cause soil acidification and compaction in the surrounding area, inhibiting crop growth. After flowing into surface water or groundwater, it may cause eutrophication (algal blooms) or heavy metal contamination, disrupting the balance of aquatic ecosystems. The amount of leachate generated is significantly affected by climatic conditions (rainfall, evaporation), the physical characteristics of the stockpile (moisture content, porosity, permeability), and the stockpiling method (seepage prevention measures, cover layer type). For example, stockpiles without seepage prevention treatment can generate 30% to 50% more leachate than those with seepage prevention treatment, highlighting the importance of source control.

[0003] Traditional treatment of phosphogypsum leachate mainly employs neutralization precipitation and chemical coagulation. The former adjusts the pH by adding lime slurry to induce the precipitation of phosphate and fluoride ions, but requires large amounts of reagents, is difficult to dewater the sludge, and generates additional solid waste. The latter relies on coagulants to coagulate pollutants, but has a low removal rate for dissolved pollutants and is difficult to utilize as a resource for sludge. Both methods suffer from high reagent consumption, high treatment costs, complex processes, and the risk of secondary pollution, making efficient and economical treatment difficult. Summary of the Invention

[0004] To address the technical problems existing in the treatment of phosphogypsum leachate in the prior art, the present invention aims to provide a method for treating phosphogypsum leachate using serpentine minerals. This method utilizes natural serpentine minerals or serpentine-containing tailings as adsorbent materials. With only simple activation treatment, it can be used to adsorb and mineralize pollutants such as fluoride and phosphorus in phosphogypsum leachate. At the same time, it can increase the pH of phosphogypsum leachate, fully realizing the harmless treatment of phosphogypsum leachate. Moreover, the treated tailings can be utilized as resources, and the purified waste liquid can be recycled without secondary pollution. Compared with the prior art, this method can reduce the treatment process of phosphogypsum leachate, reduce treatment costs, improve economic efficiency, realize the co-treatment of waste, and promote the coordinated and sustainable development of multiple industries.

[0005] To achieve the above-mentioned technical objectives, the present invention provides a method for treating phosphogypsum leachate using serpentine minerals. The method involves activating the serpentine minerals and then mixing them with the phosphogypsum leachate to carry out a fluoride-phosphorus mineralization reaction. After the reaction is completed, solid-liquid separation is performed to obtain defluorinated phosphorus leachate and fluoride-phosphorus mineralization residue.

[0006] The key to this invention lies in using serpentine as an adsorbent material, which enables the selective adsorption and mineralization of fluoride and phosphate ions in phosphogypsum leachate, while simultaneously increasing the pH of acidic phosphogypsum leachate. This method fully utilizes the layered silicate structure of serpentine, which possesses strong physical adsorption capabilities. Furthermore, after activation, the active groups and unsaturated Si-O-Si bonds on the surface of serpentine interact with Mg... 2+ The increased number of adsorption sites allows for selective adsorption of fluoride ions and phosphate ions at room temperature, while simultaneously releasing OH-. - Mg 2+ This method not only increases the pH value of phosphogypsum leachate, but also allows the fluoride ions and phosphate ions adsorbed by serpentine to mineralize and form magnesium fluoride and magnesium phosphate crystals, thereby reducing the fluoride and phosphorus content of phosphogypsum leachate and achieving simultaneous reduction of soluble fluoride and soluble phosphorus in phosphogypsum leachate.

[0007] As a preferred embodiment, the activation treatment includes mechanical activation and / or thermal activation. Mechanical activation can refine the particle size of serpentine minerals, increase their specific surface area, and enhance their reactivity. Thermal activation, through high-temperature treatment, lowers the reaction energy barrier and improves their reactivity. The most preferred activation treatment includes both mechanical and thermal activation, which can more effectively improve the mineralization ability of serpentine minerals for fluoride and phosphate ions.

[0008] As a preferred embodiment, the mechanical activation treatment involves controlling the particle size of the pulverized serpentine mineral to be within the range of 15-150 μm. Mechanical activation refines the particle size of the serpentine mineral, increases its specific surface area, and stores mechanical energy in bond energy, thus lowering its reaction energy barrier. Mechanical activation treatment can be achieved, for example, by mechanical ball milling. Preferred ball milling conditions are: a ball milling speed of 300-500 rpm and a ball milling time of 30-90 min.

[0009] As a preferred embodiment, the thermal activation treatment involves heat-treating the serpentine mineral at 500-750°C for 1-3 hours. This high-temperature treatment increases the content of active magnesium and other minerals within the serpentine, improves its ability to mineralize fluoride ions and phosphate, and also facilitates the release of OH groups. - ability.

[0010] As a preferred embodiment, the phosphorus content in the phosphogypsum leachate is 1000~2000 mg / L, the fluorine content is ≤400 mg / L, and the pH is 2~4.

[0011] As a preferred embodiment, the solid-liquid ratio of the serpentine mineral to the phosphogypsum leachate is 1 kg: 10~50 L. The amount of serpentine mineral added to the phosphogypsum leachate is determined based on the amount of free fluoride ions and phosphate ions in the phosphogypsum leachate. If the amount of serpentine mineral is too low, the goal of effectively reducing fluoride ions and phosphate ions in the phosphogypsum leachate will not be achieved.

[0012] As a preferred embodiment, the conditions for the fluorophosphorus mineralization reaction are: temperature controlled at 10~35℃, stirring speed at 50~200r / m, and time at 10~30min.

[0013] As a preferred option, the defluorinated phosphorus leachate is either directly discharged, used for pH adjustment of the phosphogypsum leachate to be treated, or incorporated into the municipal sewage network, with the destination of the leachate determined through periodic monitoring. Every 10 minutes, the concentrations of soluble phosphorus and fluoride in the liquid phase after the solid-liquid reaction and the pH of the leachate are monitored. If these concentrations do not exceed the Class A standard of the Integrated Wastewater Discharge Standard (GB 8978-1996) or meet local sewage discharge standards, the leachate is directly discharged. Otherwise, serpentine powder or serpentine tailings powder is added again for a secondary liquid-phase reaction based on the remaining concentration until the standards are met.

[0014] As a preferred option, the fluorophosphate mineralized slag is used as a soil conditioner.

[0015] The serpentine minerals of this invention include natural serpentine ore or tailings containing serpentine.

[0016] The phosphogypsum leachate of the present invention is a phosphogypsum leachate from a phosphogypsum chemical industry, a phosphogypsum washing product, or other acidic wastewater containing fluoride ions and phosphate ions.

[0017] The method for treating phosphogypsum leachate using serpentine minerals provided by this invention includes the following specific steps:

[0018] ① Activation: Natural serpentine or tailings containing serpentine S0 are mechanically crushed to 15-150 μm to obtain serpentine powder S1; or, natural serpentine or tailings containing serpentine S0 are heat-treated at 500-750℃ for 1-3 hours to obtain serpentine powder S1; or, natural serpentine or tailings containing serpentine S0 are mechanically crushed to 15-150 μm and then heat-treated at 500-750℃ for 1-3 hours to obtain serpentine powder S1; or, natural serpentine or tailings containing serpentine S0 are first heat-treated at 500-750℃ for 1-3 hours and then mechanically crushed to 15-150 μm to obtain serpentine powder S1.

[0019] ② Liquid phase reaction: The solid-liquid ratio of serpentine powder S1 to phosphogypsum leachate L0 is 1kg:30~50L. The reaction temperature is controlled at 10~35℃, the stirring speed is 50~200r / m, and the reaction time is 10~30min. After filtration, filter residue SP and filtrate L1 are obtained.

[0020] ③ Circulating reaction: The concentrations of soluble phosphorus and fluorine in the liquid phase after the solid-liquid reaction and the pH of the leachate are tested every 10 minutes. If the concentrations measured twice consecutively are lower than the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) or meet the local discharge standard, the wastewater is discharged directly into the wastewater treatment network. Otherwise, serpentine powder or serpentine tailings powder is added again according to the remaining concentration for a secondary liquid phase reaction until the standard is met.

[0021] ④ Conditioning of leachate: Mix filtrate L2 and phosphogypsum leachate L at a ratio of 1:1 and stir for 10 minutes. Let stand for 10 minutes and filter to obtain filtrate L3 and filter residue SP3.

[0022] ⑤ Result Evaluation: The filtrate is tested and qualified according to GB 11893-89 "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method" and HJ873-2017 "Determination of Water-Soluble Fluorides and Total Fluorides in Soil - Ion Selective Electrode Method", and may be discharged into the municipal sewage network; the filter residue is evaluated according to GB 15618-2018 "Soil Environmental Quality - Agricultural Land Soil Pollution Risk Control Standard (Trial)", and after passing the evaluation, the filter residue SP2 and SP3 and their mixture are used for agricultural purposes.

[0023] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0024] This invention uses serpentine and its tailings as the main raw materials and phosphogypsum leachate as the treatment target. It utilizes the release of hydroxide ions from serpentine powder in solution to adjust the pH of the leachate without the need for additional reagents. Taking advantage of the layered structure of serpentine, phosphorus and fluoride in the phosphogypsum leachate are transferred from the liquid phase to the solid phase through physical and chemical adsorption, effectively reducing pollutants in the phosphogypsum leachate. Experimental data show that the final filtrate pH increases to 7.0-8.5, and the concentrations of soluble phosphorus and fluoride decrease from 2000 mg / L and 400 mg / L to below 0.5 mg / L and 10 mg / L, respectively, meeting the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996). The final filter residue leaching concentration meets the Class III standard of the "Groundwater Quality Standard" (GB / T 14848-2017). Attached Figure Description

[0025] Figure 1 shows the XRD characteristics of serpentine tailings powder, mechanically activated serpentine tailings powder in Example 3, and filter residue SP1 in Example 4; where C represents serpentine tailings powder, B represents mechanically activated serpentine tailings powder in Example 3, and A represents filter residue SP1 in Example 4; from Figure 1 It can be seen that after mechanical activation, the d001 crystal plane at 0.741 nm (corresponding to 2θ≈11.9°) and the d002 crystal plane at 0.365 nm (corresponding to 2θ=24.3°) of the serpentine tailings still exist, but the characteristic peak at the d001 crystal plane is weakened after mechanical activation. In contrast, the characteristic peaks at both crystal planes disappear in the serpentine filter residue after mechanically and thermally activated serpentine tailings powder reacts with leachate, and the residue exhibits an overall amorphous state.

[0026] Figure 2 shows scanning electron microscope (SEM) images of serpentine tailings powder, mechanically activated serpentine tailings powder in Example 3, thermally activated + mechanically activated serpentine tailings powder in Example 4, and filter residue SP1 in Example 4; where a is serpentine tailings powder, b is mechanically activated serpentine tailings powder in Example 3, c is mechanically activated + thermally activated serpentine tailings powder in Example 4, and d is filter residue SP1 in Example 4; from Figure 2 It can be seen that serpentine tailings powder and mechanically activated serpentine tailings powder are generally in a layered stacked state with clear outlines; the layered stacked state of serpentine tailings powder after thermomechanical activation gradually disappears; after the serpentine tailings powder after thermo-activation and mechanical activation reacts with leachate, it no longer has the original morphology of serpentine tailings, and at the same time, it exhibits a porous structure due to acid etching. Detailed Implementation

[0027] The following specific embodiments are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims.

[0028] Example 1

[0029] 1. Raw material sources: L of phosphogypsum leachate was taken from the inlet, middle, outlet and dead zone of the leachate collection pond of the phosphogypsum stockpile in Yidu Ecological Industrial Park of Xingfa Group. There were 20 sampling points, with 200 mL of each sample taken. The samples were mixed after sampling. The phosphorus content was 1895 mg / L, the fluorine content was 403 mg / L, and the pH was 2.36. S0 of serpentine tailings came from Qinghai Chuang'an Co., Ltd.

[0030] 2. Primary liquid phase reaction: After drying serpentine tailings powder S0 at 200℃ for 12h, it is passed through a 1mm manual sieve to obtain serpentine tailings powder S1. The solid-liquid ratio of serpentine tailings powder S1 to leachate L is 1kg:50L. The reaction temperature is controlled at 30℃, the stirring speed is 100r / m, and the reaction time is 30min. After filtration, filter residue SP1 and filtrate L1 are obtained.

[0031] 3. Secondary liquid phase reaction: Add the new serpentine tailings powder S1 to the filtrate L1, set the solid-liquid ratio to 1kg:30L, control the reaction temperature at 30℃, the stirring speed at 100r / m, and the reaction time at 30min. When the concentration meets the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) or the local discharge standard, stop the secondary liquid phase reaction and filter to obtain SP2 and filtrate L2.

[0032] 4. Conditioning of leachate: Mix part of the filtrate L2 with the subsequent batch of phosphogypsum leachate L0. Set the proportion according to the phosphorus content, fluoride content and pH access requirements of the liquid phase reaction. After standing for 10 minutes, filter. Return the filtrate to the primary liquid phase reaction. Mix the filter residue SP3 with SP2 to obtain the final filter residue, or use it for farmland soil improvement.

[0033] Results Evaluation: The filtrate was tested according to GB 11893-89 "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method" and HJ873-2017 "Determination of Water-Soluble Fluoride and Total Fluoride in Soil - Ion Selective Electrode Method". The final filtrate pH increased to 7.82, and the concentrations of soluble phosphorus and fluoride decreased to 76.25 mg / L and 25.62 mg / L, respectively. The final filter residue had a fluoride leaching concentration of 0.92 mg / L, which meets the Class I standard of "Groundwater Quality Standard" (GB / T 14848-2017). According to GB 38400-2019 "Limits of Toxic and Hazardous Substances in Fertilizers", the filter residues SP2 and SP3 and their mixtures were evaluated and found to meet the requirements. The results are detailed in the table below.

[0034]

[0035] Example 2

[0036] 1. Raw material sources: L of phosphogypsum leachate was taken from the inlet, middle, outlet and dead zone of the leachate collection pond of the phosphogypsum stockpile in Yidu Ecological Industrial Park of Xingfa Group. There were 20 sampling points, with 200 mL of each sample taken. The samples were mixed after sampling. The phosphorus content was 1895 mg / L, the fluorine content was 403 mg / L, and the pH was 2.36. S0 of serpentine tailings came from Qinghai Chuang'an Co., Ltd.

[0037] 2. Primary liquid phase reaction: After drying serpentine tailings powder S0 at 200℃ for 12h, it is passed through a 1mm manual sieve to obtain serpentine tailings powder S1. After calcining at 750℃ for 2h, it is passed through a 1mm manual sieve to obtain serpentine tailings powder S2. The solid-liquid ratio of serpentine tailings powder S2 to leachate L is 1kg:50L. The reaction temperature is controlled at 30℃, the stirring speed is 100r / m, and the reaction time is 30min. After filtration, filter residue SP1 and filtrate L1 are obtained.

[0038] 3. Secondary liquid phase reaction: Add the new serpentine tailings powder S2 to the filtrate L1, set the solid-liquid ratio to 1kg:30L, control the reaction temperature at 30℃, the stirring speed at 100r / m, and the reaction time at 30min. When the concentration meets the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) or the local discharge standard, stop the secondary liquid phase reaction and filter to obtain SP2 and filtrate L2.

[0039] 4. Conditioning of leachate: Mix part of the filtrate L2 with the subsequent batch of phosphogypsum leachate L0. Set the proportion according to the phosphorus content, fluoride content and pH access requirements of the liquid phase reaction. After standing for 10 minutes, filter. Return the filtrate to the primary liquid phase reaction. Mix the filter residue SP3 with SP2 to obtain the final filter residue, or use it for farmland soil improvement.

[0040] Results Evaluation: The filtrate was tested according to GB 11893-89 "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method" and HJ873-2017 "Determination of Water-Soluble Fluoride and Total Fluoride in Soil - Ion Selective Electrode Method". The final filtrate pH increased to 7.22, and the concentrations of soluble phosphorus and fluoride decreased to 12.17 mg / L and 29.48 mg / L, respectively. The final filter residue had a fluoride leaching concentration of 0.91 mg / L, which meets the Class I standard of "Groundwater Quality Standard" (GB / T 14848-2017). According to GB 38400-2019 "Limits of Toxic and Hazardous Substances in Fertilizers", the filter residues SP2 and SP3 and their mixtures were evaluated and found to meet the requirements. The results are detailed in the table below.

[0041]

[0042] Example 3

[0043] 1. Raw material sources: L of phosphogypsum leachate was taken from the inlet, middle, outlet and dead zone of the leachate collection pond of the phosphogypsum stockpile in Yidu Ecological Industrial Park of Xingfa Group. There were 20 sampling points, with 200 mL of each sample taken. The samples were mixed after sampling. The phosphorus content was 1895 mg / L, the fluorine content was 403 mg / L, and the pH was 2.36. S0 of serpentine tailings came from Qinghai Chuang'an Co., Ltd.

[0044] 2. Primary liquid-phase reaction: After serpentine tailings powder (SO) is dried at 200℃ for 12 hours, it is subjected to high-energy mechanical ball milling at a speed of 400 rpm for 60 minutes, with D controlled. 50 Serpentine tailings powder S1 was obtained with a particle size of approximately 13 μm. The solid-liquid ratio of serpentine tailings powder S1 to leachate L was 1 kg: 50 L. The reaction temperature was controlled at 30 °C, the stirring speed was 100 r / m, and the reaction time was 30 min. After filtration, filter residue SP1 and filtrate L1 were obtained.

[0045] 3. Secondary liquid phase reaction: Add the new serpentine tailings powder S1 to the filtrate L1, set the solid-liquid ratio to 1kg:30L, control the reaction temperature at 30℃, the stirring speed at 100r / m, and the reaction time at 30min. When the concentration meets the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) or the local discharge standard, stop the secondary liquid phase reaction and filter to obtain SP2 and filtrate L2.

[0046] 4. Conditioning of leachate: Mix part of the filtrate L2 with the subsequent batch of phosphogypsum leachate L0. Set the ratio according to the phosphorus content, fluorine content and pH requirements of the liquid phase reaction. After standing for 10 minutes, filter. Return the filtrate to the first-stage liquid phase reaction. Mix the filter residue SP3 with SP2 to obtain the final filter residue, or use it for farmland soil improvement.

[0047] Results Evaluation: The filtrate was tested according to GB 11893-89 "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method" and HJ873-2017 "Determination of Water-Soluble Fluoride and Total Fluoride in Soil - Ion Selective Electrode Method". The final filtrate pH increased to 8.85, and the concentrations of soluble phosphorus and fluoride decreased to 0.42 mg / L and 7.61 mg / L, respectively, meeting the Class A standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996). The final filter residue had a fluoride leaching concentration of 0.6 mg / L, meeting the Class I standard of the "Groundwater Quality Standard" (GB / T14848-2017). According to GB 38400-2019 "Limits of Toxic and Hazardous Substances in Fertilizers", the filter residues SP2 and SP3 and their mixtures were evaluated as meeting the requirements. The results are detailed in the table below.

[0048]

[0049] Example 4

[0050] 1. Raw material sources: L of phosphogypsum leachate was taken from the inlet, middle, outlet and dead zone of the leachate collection pond of the phosphogypsum stockpile in Yidu Ecological Industrial Park of Xingfa Group. There were 20 sampling points, with 200 mL of each sample taken. The samples were mixed after sampling. The phosphorus content was 1895 mg / L, the fluorine content was 403 mg / L, and the pH was 2.36. S0 of serpentine tailings came from Qinghai Chuang'an Co., Ltd.

[0051] 2. Raw material pretreatment: Serpentine tailings (SO) were sieved through a 1mm sieve, roasted at 750℃ for 2 hours, and then subjected to high-energy mechanical ball milling for 20 minutes at a speed of 350 rpm to obtain D. 50 Serpentine tailings powder S1 with a particle size of approximately 75 μm.

[0052] 3. Primary liquid phase reaction: The solid-liquid ratio of serpentine tailings powder S1 to phosphogypsum leachate L is 1:50. The reaction temperature is controlled at 30℃, the stirring speed is 100r / m, and the reaction time is 30min. After filtration, filter residue SP1 and filtrate L1 are obtained.

[0053] 4. Secondary liquid phase reaction: Add the new serpentine tailings powder S1 to the phosphogypsum filtrate L1, set the solid-liquid ratio to 1kg:30L, control the reaction temperature at 30℃, the stirring speed at 100r / m, and the reaction time at 30min. When the concentration meets the Class A standard of the "Integrated Wastewater Discharge Standard" (GB 8978-1996) or meets the local discharge standard, stop the secondary liquid phase reaction and filter to obtain SP2 and filtrate L2.

[0054] 5. Conditioning of leachate: Mix part of the filtrate L2 with the subsequent batch of phosphogypsum leachate L0. Set the ratio according to the phosphorus content, fluorine content and pH requirements of the liquid phase reaction. After standing for 10 minutes, filter. Return the filtrate to the primary liquid phase reaction. Mix the filter residue SP3 and SP2 to obtain the final filter residue, or use it for farmland soil improvement.

[0055] Results Evaluation: The filtrate was tested according to GB 11893-89 "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method" and HJ873-2017 "Determination of Water-Soluble Fluoride and Total Fluoride in Soil - Ion Selective Electrode Method". The final filtrate pH increased to 7.54, and the concentrations of soluble phosphorus and fluoride decreased to 0.11 mg / L and 2.23 mg / L, respectively, meeting the Class A standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996). The final filter residue had a fluoride leaching concentration of 0.22 mg / L, meeting the Class I standard of the "Groundwater Quality Standard" (GB / T14848-2017). According to GB 38400-2019 "Limits of Toxic and Hazardous Substances in Fertilizers", the filter residues SP2 and SP3 and their mixtures were evaluated as meeting the requirements. The results are detailed in the table below.

[0056]

Claims

1. A method for treating phosphogypsum leachate with serpentine mineral, characterized by: The serpentine mineral is activated and mixed with phosphogypsum leachate to carry out fluorophosphor mineralization reaction, and after the reaction is completed, solid-liquid separation is carried out to obtain defluorophosphor leachate and fluorophosphor mineralization slag.

2. A method for treating phosphogypsum leachate with serpentine mineral according to claim 1, characterized in that: The activation treatment comprises mechanical activation treatment and / or thermal activation treatment.

3. The method for treating phosphogypsum leachate by using serpentine mineral according to claim 2, characterized in that: The mechanical activation treatment is to control the particle size of the crushed serpentine mineral in the range of 15-150 μm. The thermal activation treatment is to heat the serpentine mineral at a temperature of 500-750 ℃ for 1-3 h.

4. A method for treating phosphogypsum leachate using serpentine mineral according to claim 1, characterized in that: The phosphorus content in the phosphogypsum leachate is 1000-2000 mg / L, the fluorine content is ≤400 mg / L, and the pH is 2-4.

5. A method for treating phosphogypsum leachate with serpentine mineral according to claim 1, characterized in that: The solid-liquid ratio of the serpentine mineral to the phosphogypsum leachate is 1 kg:10-50 L.

6. The method for treating phosphogypsum leachate with serpentine mineral according to any one of claims 1-5, characterized in that: The conditions of the fluorophosphor mineralization reaction are as follows: the temperature is controlled in the range of 10-35 ℃, the stirring speed is 50-200 r / m, and the time is 10-30 min.

7. A method for treating phosphogypsum leachate with serpentine mineral according to claim 1, characterized in that: The defluorophosphor leachate is directly discharged, or is used for pH adjustment of the phosphogypsum leachate to be treated, or is discharged into the municipal sewage pipe network.

8. A method for treating phosphogypsum leachate with serpentine mineral according to claim 1, characterized in that: The fluorophosphor mineralization slag is used as a soil conditioner.

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