Recycling production process and device for synthesizing calcium fluoride from fluorine-containing wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a production process and device for synthesizing calcium fluoride from fluorine-containing wastewater and recycling the calcium fluoride, and the processes of wastewater pretreatment, neutralization and precipitation reaction, solid-liquid separation, mixing homogenization, drying and the like are organically combined to form a complete fluorine-containing wastewater treatment and calcium fluoride recycling system. The method has the advantages that the fluorine resource recycling and production cost saving are realized by mixing and homogenizing the treated calcium fluoride and fluorite and then recycling, the purity of the calcium fluoride product is ensured to reach 60-70% through experimental verification, the recycling requirement is met, zero discharge or up-to-standard discharge of the fluorine-containing wastewater is realized, and the method is suitable for industrial production. The method provided by the invention can recover a certain amount of fluorine element and reduce environmental pollution, and solves the technical problems of overhigh energy consumption, low recovery rate and low purity although the existing method for preparing calcium fluoride from fluorine-containing wastewater can recover a certain amount of fluorine element and reduce environmental pollution and resource waste.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a production process and a device for recycling calcium fluoride synthesized from fluorine-containing wastewater. Background Art

[0002] In recent years, with the rapid development of the fluorine chemical industry, the discharge of fluorine-containing wastewater has brought a threat to the ecological environment and has become the biggest obstacle to the sustainable development of the industry. The existing treatment processes for fluorine-containing wastewater mainly include ion exchange, membrane separation (electrodialysis and reverse osmosis), adsorption, precipitation (chemical precipitation and coagulation precipitation), etc. Each process is aimed at reducing the fluoride content in the wastewater, which brings about problems of material consumption, energy consumption and secondary product disposal to varying degrees. The treatment of fluorine-containing wastewater not only increases the economic burden on enterprises, but also brings different degrees of secondary pollution risks.

[0003] Prior art CN101624203A discloses a method for preparing calcium fluoride from fluoride-containing wastewater, wherein the fluoride content in the fluoride-containing wastewater is increased by heating and concentration and controlled to be above 1%, and then a calcium chloride solution is added to react to generate calcium fluoride precipitation. By purifying calcium fluoride from fluoride-containing wastewater, resources are saved, the environment is protected, and a heavy economic burden is not imposed on the enterprise.

[0004] However, although the above method for preparing calcium fluoride from fluoride-containing wastewater can recover a certain amount of fluorine element and reduce environmental pollution and resource waste, it has the problems of excessive energy consumption, low recovery rate and low purity. Summary of the invention

[0005] The purpose of the present invention is to provide a production process and device for recycling calcium fluoride synthesized from fluorine-containing wastewater, which solves the technical problems that the existing method for preparing calcium fluoride from fluorine-containing wastewater can recover a certain amount of fluorine element and reduce environmental pollution and resource waste, but has excessive energy consumption, low recovery rate and low purity.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a production process for recycling calcium fluoride synthesized from fluorine-containing wastewater, comprising the following steps:

[0007] Fluoride-containing wastewater treatment, collecting the fluoride-containing wastewater, and after collecting a suitable amount, pre-treating the fluoride-containing wastewater;

[0008] Preparation of calcium fluoride: after pretreatment, the fluorine-containing wastewater is subjected to a neutralization precipitation reaction and a solid-liquid separation reaction in sequence to obtain calcium fluoride slurry;

[0009] Calcium fluoride treatment, wherein the calcium fluoride slurry is subjected to flocculation and filter pressing, mixing and homogenization, and drying in sequence to obtain a high-purity calcium fluoride-fluorite mixture;

[0010] Calcium fluoride is recycled and the dried calcium fluoride-fluorite mixture is stored and used as a raw material for the main device to achieve recycling.

[0011] The specific steps of treating the fluorine-containing wastewater, collecting the fluorine-containing wastewater, and pre-treating the fluorine-containing wastewater after collecting an appropriate amount are as follows:

[0012] Collecting the fluorine-containing wastewater into a wastewater collection pool;

[0013] After collecting a suitable amount of the fluorine-containing wastewater, the fluorine-containing wastewater is subjected to a preliminary homogenization treatment.

[0014] The specific steps of preparing calcium fluoride, after pretreatment, sequentially subjecting the fluorine-containing wastewater to a neutralization precipitation reaction and a solid-liquid separation reaction to obtain calcium fluoride slurry are as follows:

[0015] After the fluorine-containing wastewater is subjected to preliminary homogenization treatment, the fluorine-containing wastewater is transferred to a tertiary sedimentation tank for neutralization and precipitation reaction to obtain calcium fluoride precipitation;

[0016] The calcium fluoride precipitate is transferred to a clarification tank, and a solid-liquid separation reaction is performed on the calcium fluoride precipitate to obtain calcium fluoride slurry.

[0017] The specific steps of treating calcium fluoride, sequentially flocculating and filtering, mixing and homogenizing, and drying the calcium fluoride slurry to obtain a high-purity calcium fluoride-fluorite mixture are as follows:

[0018] After obtaining the calcium fluoride slurry, transferring the calcium fluoride slurry to a flocculant stirring tank, and adding a proper amount of flocculant to the flocculant stirring tank to promote the aggregation of solid particles in the calcium fluoride slurry;

[0019] Afterwards, the calcium fluoride slurry is transported to a filter press by the slurry pump for solid-liquid separation to obtain a calcium fluoride filter cake and a filtrate;

[0020] The calcium fluoride filter cake is mixed and homogenized with a certain amount of fluorite to form a uniform mixture, and then dried by a fluorite dryer to remove moisture, thereby obtaining a high-purity calcium fluoride-fluorite mixture.

[0021] After obtaining the calcium fluoride filter cake, the calcium fluoride filter cake needs to be further processed, such as washing and drying, to improve the purity and recovery rate of the calcium fluoride filter cake, and then the calcium fluoride filter cake is mixed and homogenized with a certain amount of fluorite.

[0022] The calcium fluoride is recycled and the dried calcium fluoride-fluorite mixture is stored for use as a raw material in the main device. The specific steps for achieving recycling are:

[0023] After obtaining the high-purity calcium fluoride-fluorite mixture, the dried calcium fluoride-fluorite mixture is transported to a silo for storage through a plate feeder, a feed screw, and a bucket elevator;

[0024] The stored calcium fluoride-fluorite mixture is recycled to the main device for use, thereby realizing the recycling of resources.

[0025] In a second aspect, the present invention further provides a production device for recycling calcium fluoride synthesized from fluorine-containing wastewater, comprising a wastewater collection tank, a three-stage sedimentation tank, a clarifier, a mud pump, a flocculant stirring tank, a filter press, a fluorite dryer, a plate feeder, a feeding screw, a bucket elevator, a silo and a main device, wherein the wastewater collection tank is used to collect fluorine-containing wastewater, the three-stage sedimentation tank is used to neutralize and precipitate the fluorine-containing wastewater, the clarifier and the mud pump are used in combination to separate the fluorine-containing wastewater into solid and liquid to obtain calcium fluoride slurry, the flocculant stirring tank, the filter press and the fluorite dryer are used in combination to obtain a high-purity calcium fluoride-fluorite mixture, the plate feeder, the feeding screw and the bucket elevator are used in combination to transport the calcium fluoride-fluorite mixture to the silo for storage, and the main device is used to recycle the calcium fluoride-fluorite mixture.

[0026] The invention discloses a production process and device for recycling calcium fluoride synthesized from fluorine-containing wastewater. The process adopts a lime milk neutralization precipitation method and controls the lime milk addition amount, reaction temperature, stirring rate, reaction time and the like to maximize the generation amount and purity of calcium fluoride. The process includes wastewater pretreatment, neutralization precipitation reaction, solid-liquid separation, mixing homogenization and drying, etc., so as to form a complete fluorine-containing wastewater treatment and calcium fluoride recycling system, and can realize automatic and intelligent control. The treated calcium fluoride is mixed with fluorite for homogenization and then recycled, so as to realize the recycling of fluorine resources and the saving of production cost. The process ensures that the purity of the calcium fluoride product reaches 60%-70%, meets the recycling and use requirements, realizes zero discharge or up-to-standard discharge of fluorine-containing wastewater, reduces environmental pollution, and solves the technical problems that the existing method for preparing calcium fluoride from fluorine-containing wastewater can recover a certain amount of fluorine element, reduce environmental pollution and waste of resources, but has excessive energy consumption, low recovery rate and low purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0028] Figure 1 It is a flow chart of the production process of synthesizing calcium fluoride from fluorine-containing wastewater for recycling and reuse according to the first embodiment of the present invention.

[0029] Figure 2 This is a specific step diagram of the treatment of fluorine-containing wastewater in the first embodiment of the present invention, which includes collecting fluorine-containing wastewater and, after collecting a suitable amount, performing preliminary pretreatment on the fluorine-containing wastewater.

[0030] Figure 3 This is a specific step diagram of the preparation of calcium fluoride according to the first embodiment of the present invention. After pretreatment, the fluorine-containing wastewater is subjected to a neutralization precipitation reaction and a solid-liquid separation reaction in sequence to obtain calcium fluoride slurry.

[0031] Figure 4 This is a specific step diagram of the calcium fluoride treatment of the first embodiment of the present invention, in which the calcium fluoride slurry is subjected to flocculation and filter pressing, mixing and homogenization, and drying in sequence to obtain a high-purity calcium fluoride-fluorite mixture.

[0032] Figure 5 This is a specific step diagram of the recycling of calcium fluoride in the first embodiment of the present invention, in which the dried calcium fluoride-fluorite mixture is stored for use as a raw material by the main device to achieve recycling.

[0033] Figure 6 It is a schematic diagram of the structure of the production of recycling and reuse of calcium fluoride synthesized from fluorine-containing wastewater in the second embodiment of the present invention.

[0034] In the figure: 101-wastewater collection tank, 102-tertiary sedimentation tank, 103-clarification tank, 104-mud pump, 105-flocculant mixing tank, 106-filter press, 107-fluorite dryer, 108-plate feeder, 109-feeding screw, 110-bucket elevator, 111-silo, 112-main device. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0036] First embodiment:

[0037] See also Figures 1 to 5 The present invention provides a production process for synthesizing calcium fluoride from fluorine-containing wastewater for recycling, comprising the following steps:

[0038] S1. Treatment of fluorine-containing wastewater: collecting the fluorine-containing wastewater, and after collecting a suitable amount, performing preliminary pretreatment on the fluorine-containing wastewater.

[0039] Specifically, the fluorine-containing wastewater treatment comprises collecting the fluorine-containing wastewater, and after collecting a suitable amount, performing preliminary pretreatment on the fluorine-containing wastewater.

[0040] S11, collecting the fluorine-containing wastewater into a wastewater collection pool 101;

[0041] S12. After collecting a suitable amount of the fluorine-containing wastewater, the fluorine-containing wastewater is subjected to preliminary homogenization treatment.

[0042] S2. Preparation of calcium fluoride: After pretreatment, the fluorine-containing wastewater is subjected to a neutralization precipitation reaction and a solid-liquid separation reaction in sequence to obtain calcium fluoride slurry.

[0043] Specifically, the preparation of calcium fluoride comprises the following steps: after pretreatment, the fluorine-containing wastewater is subjected to a neutralization precipitation reaction and a solid-liquid separation reaction in sequence to obtain calcium fluoride slurry:

[0044] S21. After the fluorine-containing wastewater is subjected to preliminary homogenization treatment, the fluorine-containing wastewater is transferred to the tertiary sedimentation tank 102 for neutralization and precipitation reaction to obtain calcium fluoride precipitate.

[0045] Specifically, the specific steps of the neutralization precipitation reaction are: after the fluorine-containing wastewater is transferred to the tertiary sedimentation tank 102, lime milk is added to the tertiary sedimentation tank 102 step by step, so that the lime milk in the tertiary sedimentation tank 102 undergoes a neutralization precipitation reaction with the fluorine ions in the fluorine-containing wastewater to generate calcium fluoride precipitate; when the lime milk in the tertiary sedimentation tank 102 undergoes a neutralization precipitation reaction with the fluorine ions in the fluorine-containing wastewater, the reaction conditions are optimized by adjusting parameters such as reaction temperature, stirring rate and reaction time to increase the generation amount and purity of calcium fluoride.

[0046] S22, transferring the calcium fluoride precipitate to a clarification tank 103, performing a solid-liquid separation reaction on the calcium fluoride precipitate to obtain calcium fluoride slurry.

[0047] Specifically, the specific steps of the solid-liquid separation reaction are: after the calcium fluoride precipitate is transferred to the clarifier 103, the clarifier 103 and the mud pump 104 are used to perform solid-liquid separation on the precipitated calcium fluoride precipitate to obtain calcium fluoride slurry.

[0048] S3, calcium fluoride treatment, the calcium fluoride slurry is sequentially subjected to flocculation and filter pressing, mixed homogenization and drying to obtain a high-purity calcium fluoride-fluorite mixture.

[0049] Specifically, the calcium fluoride treatment comprises the following steps: flocculation and filter pressing, mixing and homogenization, and drying of the calcium fluoride slurry in sequence to obtain a high-purity calcium fluoride-fluorite mixture:

[0050] S31, after obtaining the calcium fluoride slurry, transferring the calcium fluoride slurry to a flocculant stirring tank 105, and adding a proper amount of flocculant to the flocculant stirring tank 105 to promote the aggregation of solid particles in the calcium fluoride slurry;

[0051] S32, then, the calcium fluoride slurry is transported to the filter press 106 by the slurry pump 104 for solid-liquid separation to obtain a calcium fluoride filter cake and a filtrate;

[0052] S33, the calcium fluoride filter cake is mixed and homogenized with a certain amount of fluorite to form a uniform mixture, and then dried by a fluorite dryer 107 to remove moisture, thereby obtaining a high-purity calcium fluoride-fluorite mixture.

[0053] Specifically, after obtaining the calcium fluoride filter cake, the calcium fluoride filter cake needs to be further processed, such as washing and drying, to improve the purity and recovery rate of the calcium fluoride filter cake, and then the calcium fluoride filter cake is mixed and homogenized with a certain amount of fluorite.

[0054] S4, recycling and utilizing calcium fluoride, storing the dried calcium fluoride-fluorite mixture and providing it to the main device 112 as a raw material to realize recycling and utilization.

[0055] Specifically, the calcium fluoride is recycled and the dried calcium fluoride-fluorite mixture is stored for use as a raw material by the main device 112. The specific steps for achieving recycling are:

[0056] S41, after obtaining the high-purity calcium fluoride-fluorite mixture, the dried calcium fluoride-fluorite mixture is transported to the silo 111 for storage through the plate feeder 108, the feed screw 109, and the bucket elevator 110;

[0057] S42, recycling the stored calcium fluoride-fluorite mixture to the main device 112 for use, so as to realize the recycling of resources.

[0058] When using the production process of synthesizing calcium fluoride from fluorine-containing wastewater of the present embodiment for recycling, the lime milk neutralization precipitation method is adopted, and the lime milk addition amount, reaction temperature, stirring rate, reaction time, etc. are controlled to maximize the generation amount and purity of calcium fluoride. By organically combining the processes of wastewater pretreatment, neutralization precipitation reaction, solid-liquid separation, mixing homogenization and drying, a complete fluorine-containing wastewater treatment and calcium fluoride recycling system is formed, and automatic and intelligent control can be realized. By mixing and homogenizing the treated calcium fluoride with fluorite and then recycling it, the recycling of fluorine resources and the saving of production costs are realized. Through experimental verification, it is ensured that the purity of the calcium fluoride product reaches 60%-70%, which meets the recycling requirements, realizes zero discharge or up-to-standard discharge of fluorine-containing wastewater, reduces environmental pollution, and solves the technical problems of excessive energy consumption, low recovery rate and low purity in the existing method for preparing calcium fluoride from fluorine-containing wastewater, although it can recover a certain amount of fluorine element and reduce environmental pollution and resource waste.

[0059] Second embodiment:

[0060] Based on the first embodiment, please refer to Figure 6 The present invention also provides a production device for recycling and synthesizing calcium fluoride from fluorine-containing wastewater, including a wastewater collection tank 101, a three-stage sedimentation tank 102, a clarification tank 103, a mud pump 104, a flocculant stirring tank 105, a filter press 106, a fluorite dryer 107, a plate feeder 108, a feeding screw 109, a bucket elevator 110, a silo 111 and a main device 112.

[0061] In this embodiment, through the coordinated use of the wastewater collection tank 101, the tertiary sedimentation tank 102, the clarification tank 103, the mud pump 104, the flocculant stirring tank 105, the filter press 106, the fluorite dryer 107, the plate feeder 108, the feed screw 109, the bucket elevator 110, the silo 111 and the main device 112, the fluorine-containing wastewater can be converted into calcium fluoride, and the calcium fluoride can be recycled, thereby realizing the recycling of fluorine resources.

[0062] The wastewater collection tank 101 is used to collect fluorine-containing wastewater, the tertiary sedimentation tank 102 is used to neutralize and precipitate the fluorine-containing wastewater, the clarification tank 103 and the mud pump 104 are used in combination to separate the fluorine-containing wastewater into solid and liquid to obtain calcium fluoride slurry, the flocculant stirring tank 105, the filter press 106 and the fluorite dryer 107 are used in combination to obtain a high-purity calcium fluoride-fluorite mixture, the plate feeder 108, the feed screw 109 and the bucket elevator 110 are used in combination to transport the calcium fluoride-fluorite mixture to the silo 111 for storage, and the main device 112 is used to recycle the calcium fluoride-fluorite mixture.

[0063] When the production device for recycling calcium fluoride synthesized from fluorine-containing wastewater of the present embodiment is used, the wastewater collection tank 101, the three-stage sedimentation tank 102, the clarification tank 103, the mud pump 104, the flocculant stirring tank 105, the filter press 106, the fluorite dryer 107, the plate feeder 108, the feed screw 109, the bucket elevator 110, the silo 111 and the main device 112 are used in coordination to form a complete fluorine-containing wastewater treatment and calcium fluoride recycling system, and can achieve The invention has realized automatic and intelligent control, and can convert fluorine-containing wastewater into calcium fluoride, and recycle calcium fluoride to realize the recycling of fluorine resources and save production costs. Through experimental verification, it is ensured that the purity of calcium fluoride products reaches 60%-70%, which meets the requirements for recycling and use, realizes zero discharge or up-to-standard discharge of fluorine-containing wastewater, reduces environmental pollution, and solves the technical problems that the existing method of preparing calcium fluoride from fluorine-containing wastewater can recover a certain amount of fluorine element and reduce environmental pollution and waste of resources, but has excessive energy consumption, low recovery rate and low purity.

[0064] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A production process for recycling calcium fluoride synthesized from fluorine-containing wastewater, characterized in that: The following steps are involved: Fluoride-containing wastewater treatment, collecting the fluoride-containing wastewater, and after collecting a suitable amount, pre-treating the fluoride-containing wastewater; Preparation of calcium fluoride: after pretreatment, the fluorine-containing wastewater is subjected to a neutralization precipitation reaction and a solid-liquid separation reaction in sequence to obtain calcium fluoride slurry; Calcium fluoride treatment, wherein the calcium fluoride slurry is subjected to flocculation and filter pressing, mixing and homogenization, and drying in sequence to obtain a high-purity calcium fluoride-fluorite mixture; Calcium fluoride is recycled and the dried calcium fluoride-fluorite mixture is stored and used as a raw material for the main device to achieve recycling.

2. The production process for recycling calcium fluoride synthesized from fluorine-containing wastewater according to claim 1, characterized in that: The specific steps of treating the fluorine-containing wastewater, collecting the fluorine-containing wastewater, and after collecting a suitable amount, pre-treating the fluorine-containing wastewater are as follows: Collecting the fluorine-containing wastewater into a wastewater collection pool; After collecting a suitable amount of the fluorine-containing wastewater, the fluorine-containing wastewater is subjected to a preliminary homogenization treatment.

3. The production process for recycling calcium fluoride synthesized from fluorine-containing wastewater as claimed in claim 1, characterized in that: The specific steps of preparing calcium fluoride, after pretreatment, sequentially performing neutralization precipitation reaction and solid-liquid separation reaction on the fluorine-containing wastewater to obtain calcium fluoride slurry are as follows: After the fluorine-containing wastewater is subjected to preliminary homogenization treatment, the fluorine-containing wastewater is transferred to a tertiary sedimentation tank for neutralization and precipitation reaction to obtain calcium fluoride precipitation; The calcium fluoride precipitate is transferred to a clarification tank, and a solid-liquid separation reaction is performed on the calcium fluoride precipitate to obtain calcium fluoride slurry.

4. The production process for recycling calcium fluoride synthesized from fluorine-containing wastewater as claimed in claim 1, characterized in that: The specific steps of the calcium fluoride treatment, which sequentially performs flocculation and filter pressing, mixing and homogenizing, and drying on the calcium fluoride slurry to obtain a high-purity calcium fluoride-fluorite mixture, are as follows: After obtaining the calcium fluoride slurry, transferring the calcium fluoride slurry to a flocculant stirring tank, and adding a proper amount of flocculant to the flocculant stirring tank to promote the aggregation of solid particles in the calcium fluoride slurry; Afterwards, the calcium fluoride slurry is transported to a filter press by the slurry pump for solid-liquid separation to obtain a calcium fluoride filter cake and a filtrate; The calcium fluoride filter cake is mixed and homogenized with a certain amount of fluorite to form a uniform mixture, and then dried by a fluorite dryer to remove moisture, thereby obtaining a high-purity calcium fluoride-fluorite mixture.

5. The production process for recycling calcium fluoride synthesized from fluorine-containing wastewater as claimed in claim 4, characterized in that: After obtaining the calcium fluoride filter cake, it is necessary to further process the calcium fluoride filter cake, such as washing and drying, to improve the purity and recovery rate of the calcium fluoride filter cake, and then mix the calcium fluoride filter cake with a certain amount of fluorite for homogenization.

6. The production process for recycling calcium fluoride synthesized from fluorine-containing wastewater as claimed in claim 1, characterized in that: The calcium fluoride is recycled and the dried calcium fluoride-fluorite mixture is stored for use as a raw material by the main device. The specific steps for achieving recycling are: After obtaining the high-purity calcium fluoride-fluorite mixture, the dried calcium fluoride-fluorite mixture is transported to a silo for storage through a plate feeder, a feed screw, and a bucket elevator; The stored calcium fluoride-fluorite mixture is recycled to the main device for use, thereby realizing the recycling of resources.

7. A production device for recycling calcium fluoride synthesized from fluorine-containing wastewater, applied to the production process for recycling calcium fluoride synthesized from fluorine-containing wastewater according to any one of claims 1 to 6, characterized in that: The invention comprises a wastewater collection tank, a three-stage sedimentation tank, a clarification tank, a mud pump, a flocculant stirring tank, a filter press, a fluorite dryer, a plate feeder, a feeding screw, a bucket elevator, a silo and a main device. The wastewater collection tank is used to collect fluorine-containing wastewater. The three-stage sedimentation tank is used to neutralize and precipitate the fluorine-containing wastewater. The clarification tank and the mud pump are used in combination to separate the fluorine-containing wastewater into solid and liquid to obtain calcium fluoride slurry. The flocculant stirring tank, the filter press and the fluorite dryer are used in combination to obtain a high-purity calcium fluoride-fluorite mixture. The plate feeder, the feeding screw and the bucket elevator are used in combination to transport the calcium fluoride-fluorite mixture to the silo for storage. The main device is used to recycle the calcium fluoride-fluorite mixture.

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