Glass thinning wastewater calcium fluoride crystallization process and treatment equipment used by same

Abstract

The invention discloses a calcium fluoride crystallization process for glass thinning wastewater and treatment equipment used in the process, and the treatment equipment comprises an acid water adjusting tank, a lime dispensing tank, a fluorine recovery reactor, a first-stage filter pressing device, a second-stage filter pressing device, a cleaning device, a fluorine-containing wastewater adjusting tank and a two-stage fluorine removal system, the glass thinning concentrated acid wastewater homogenized by the acid water adjusting tank and a lime solution prepared by the lime dispensing tank are crystallized in the fluorine recovery reactor to form large-particle calcium fluoride crystals; large-particle calcium fluoride crystals are subjected to filter pressing by the first-stage filter pressing device, washed by the washing device and subjected to filter pressing by the second-stage filter pressing device to obtain a high-purity large-particle calcium fluoride crystal product, and effluent of the fluorine recovery reactor, filtrate generated by dehydration and washing water generated by washing are homogenized by the fluorine-containing wastewater adjusting tank and then enter the two-stage fluorine removal system; according to the method, the high-purity calcium fluoride product can be obtained, resource circulation is achieved, and the disposal cost of an enterprise is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a glass thinning wastewater calcium fluoride crystallization process and a treatment device used in the process. BACKGROUND

[0002] The glass thinning process is a core process for reducing the thickness of a glass substrate through chemical etching or physical grinding technology. Chemical etching uses a solution such as hydrofluoric acid to dissolve the surface of the glass, and uniform thinning is achieved by controlling the reaction time and concentration. However, this process generates a large amount of hazardous and difficult-to-treat wastewater, which is characterized by high fluoride concentration, high silicon concentration, and extremely low pH.

[0003] Currently, the main treatment method for glass thinning wastewater is to use calcium salts such as lime and calcium chloride for neutralization and fluorine removal. This can restore the pH of the wastewater to neutral and remove fluoride ions and fluorosilicate ions from the wastewater, while generating a large amount of calcium fluoride-containing sludge. The calcium fluoride-containing sludge contains calcium fluoride, silica gel, and calcium silicate. Due to the fine particles, the components cannot be effectively separated, resulting in a low-purity mixture that can only be treated as solid waste. Direct disposal is expensive and leads to waste of fluorine resources. SUMMARY

[0004] To overcome the above-mentioned defects, the present application provides a glass thinning wastewater calcium fluoride crystallization process and a treatment device used in the process. The glass thinning wastewater calcium fluoride crystallization process can obtain high-purity calcium fluoride products, realize resource recycling, and reduce the disposal cost of enterprises.

[0005] The technical solution adopted by the present application to solve the technical problem is a glass thinning wastewater calcium fluoride crystallization process, comprising the following steps:

[0006] Step one: glass thinning concentrated acid wastewater and lime solution are sent into a fluorine recovery reactor at a calcium fluoride molar ratio of 0.4-0.7, the pH of the mixed solution in the fluorine recovery reactor is 4-7, most of the fluorine in the glass thinning concentrated acid wastewater undergoes crystallization reaction in the fluorine recovery reactor to generate large particle calcium fluoride crystals, most of the silicon in the glass thinning concentrated acid wastewater enters a two-stage fluorine removal system with the effluent from the fluorine recovery reactor, a small amount of silicon in the glass thinning concentrated acid wastewater forms a network of silica gel, and the large particle calcium fluoride crystals with silica gel are discharged from the crystal discharge port of the fluorine recovery reactor. The technology of induced crystallization is used to form large particle calcium fluoride crystals from the fluorine in the glass thinning concentrated acid wastewater. By controlling the pH of the mixed solution in the fluorine recovery reactor, most of the silicon remains in the water and is discharged from the fluorine recovery reactor with the effluent, and a small amount of silicon forms a network of silica gel and is discharged from the crystal discharge port of the fluorine recovery reactor with the large particle calcium fluoride crystals;

[0007] Step two: the large particle calcium fluoride crystals with silica gel on the surface are washed by pure water, the silica gel on the surface of the large particle calcium fluoride is removed by hydraulic elutriation, and then high-purity large particle calcium fluoride crystal products are obtained by dehydration, and the filtrate and washing water generated by dehydration and washing are introduced into a two-stage defluorination system, the silica gel is removed by hydraulic elutriation by using the density difference between the calcium fluoride crystals and the silica gel, and high-purity calcium fluoride crystals are obtained.

[0008] Step three: the first-stage defluorination system of the two-stage defluorination system uses a calcium agent to react with low-fluorine water containing silicon, fluoride ions react with calcium ions to form calcium fluoride precipitate, the calcium fluoride precipitate is treated as waste solid, the effluent of the first-stage defluorination system is introduced into the second-stage defluorination system, the second-stage defluorination system uses PAC and PAM coagulation and sedimentation to remove suspended solids (SS) and residual fluoride ions in the water, and the generated precipitate is treated as waste solid, the effluent of the second-stage defluorination system meets the discharge standard, the low-fluorine water containing silicon in the first-stage defluorination system reacts with calcium ions in the calcium agent to generate calcium fluoride precipitate, thereby further removing fluoride ions in the wastewater, and the second-stage defluorination system coagulates the wastewater by PAC and PAM to remove a small amount of suspended solids and residual fluoride ions in the wastewater, so that the fluoride ion concentration in the effluent of the second-stage defluorination system reaches the discharge standard and is discharged.

[0009] As a further improvement of the application, in step one, the glass thinning concentrated acid wastewater is collected in an acid water conditioning tank for homogenization, and a lime solution is prepared by stirring lime solids and water in a lime preparation tank to a certain concentration. The glass thinning concentrated acid wastewater in the photoelectric glass production enterprise is collected in the acid water conditioning tank and subjected to stirring and homogenization treatment, so that the fluoride ion concentration in the glass thinning concentrated acid wastewater entering the fluorine recovery reactor is stable, and the production of stable calcium fluoride crystal products can be effectively controlled and maintained.

[0010] As a further improvement of the application, in step one, a pH detection device is arranged in the fluorine recovery reactor to detect the pH of the mixed solution in real time, and a self-control linkage program controls the lime solution dosage according to the pH of the mixed solution. The automatic control of the lime solution dosage is realized by the pH detection device and the self-control linkage program, so that the pH of the mixed solution in the fluorine recovery reactor is always maintained between 4 and 7, intelligent control is realized, and the pH detection device is generally a pH meter.

[0011] As a further improvement of the application, in step one, the residence time of the glass thinning concentrated acid wastewater and the lime solution in the fluorine recovery reactor is controlled to be 30-60 minutes, more than 90% of the fluorine in the water inlet of the fluorine recovery reactor grows into large particle calcium fluoride in the reactor, and 80% of the silicon flows away with the water outlet of the reactor.

[0012] As a further improvement of the present application, the crystal discharge port of the fluorine recovery reactor is opened periodically to realize the periodic and quantitative discharge of the large particle calcium fluoride crystals in the fluorine recovery reactor, and a control valve is installed on the crystal discharge port of the fluorine recovery reactor, which is controlled by a control system to realize the periodic discharge of the fluorine recovery reactor, which is conducive to the stable operation of the subsequent dehydration and cleaning steps of the calcium fluoride crystals, and makes the output of the calcium fluoride crystal product stable.

[0013] As a further improvement of the present application, in step two, the large particle calcium fluoride crystals with silicon gel adhered discharged from the fluorine recovery reactor are first dehydrated by a first-stage pressure filtration device, then washed to remove the silicon gel by using pure water in a cleaning device, and the large particle calcium fluoride crystals after washing are dehydrated by a second-stage pressure filtration device, and finally the high-quality calcium fluoride particle crystal product is obtained. After dehydration by the first-stage pressure filtration device, the silicon gel and other impurities adhered to the surface of the large particle calcium fluoride crystals are effectively reduced, the amount of pure water used for cleaning can be reduced, and the cleanliness of the large particle calcium fluoride crystals after cleaning is high. The calcium fluoride particle crystal product obtained after the second-stage pressure filtration device dehydrates again has high purity, and can be recycled as a resource.

[0014] As a further improvement of the present application, the water discharged from the fluorine recovery reactor in step one and the filtrate and cleaning water generated after dehydration and washing in step two are directly discharged into a fluorine-containing wastewater conditioning tank, the fluorine-containing wastewater conditioning tank collects the silicon-containing low-fluorine water, and the silicon-containing low-fluorine water is homogenized. The silicon-containing low-fluorine water homogenized by the fluorine-containing wastewater conditioning tank enters a two-stage defluorination system for standard defluorination. The silicon-containing low-fluorine water, filtrate and cleaning water discharged from the fluorine recovery reactor are mixed and homogenized in the fluorine-containing wastewater conditioning tank, which is conducive to the effective defluorination treatment of the silicon-containing low-fluorine water by the two-stage defluorination system.

[0015] As a further improvement of the present application, in step three, the calcium agent of the first-stage defluorination system is at least one of calcium hydroxide and calcium chloride.

[0016] The glass thinning wastewater treatment equipment comprises an acid water adjusting tank, a lime dosing tank, a fluorine recovery reactor, a first-stage pressure filtration device, a second-stage pressure filtration device, a cleaning device, a fluorine-containing wastewater adjusting tank and a two-stage fluorine removal system, the acid water adjusting tank is used for containing glass thinning concentrated acid wastewater, the lime dosing tank is used for mixing lime solids and water to form a lime solution, a stirrer is arranged in the lime dosing tank, the stirrer can stir the lime solids and water, the acid water adjusting tank and the lime dosing tank are communicated with the water inlet and the medicine inlet of the fluorine recovery reactor through pipelines, the glass thinning concentrated acid wastewater in the acid water adjusting tank and the lime solution in the lime dosing tank are sent into the fluorine recovery reactor through lifting pumps, the crystal outlet of the fluorine recovery reactor is communicated with the inlet of the first-stage pressure filtration device, the first-stage pressure filtration device can dewater the large particle calcium fluoride crystals with silica gel, the solid outlet of the first-stage pressure filtration device is communicated with the inlet of the cleaning device, the cleaning device is further provided with a pure water inlet for the pure water, a cleaning water outlet and a solid outlet, the cleaning device can wash the large particle calcium fluoride crystals with silica gel, the solid outlet of the cleaning device is communicated with the inlet of the second-stage pressure filtration device, the second-stage pressure filtration device can dewater the clean large particle calcium fluoride crystals, the dewatering outlets of the first-stage pressure filtration device and the second-stage pressure filtration device, the cleaning water outlet of the cleaning device and the water outlet of the fluorine recovery reactor are communicated with the water inlet of the fluorine-containing wastewater adjusting tank through pipelines, a stirrer is arranged in the fluorine-containing wastewater adjusting tank, the stirrer in the fluorine-containing wastewater adjusting tank can stir and homogenize various fluorine-containing wastewaters, the water outlet of the fluorine-containing wastewater adjusting tank is communicated with the two-stage fluorine removal system through a pipeline, the two-stage fluorine removal system comprises a first-stage fluorine removal system and a second-stage fluorine removal system which are sequentially communicated through pipelines, the first-stage fluorine removal system and the second-stage fluorine removal system are respectively provided with dosing devices, the dosing device of the first-stage fluorine removal system can add calcium agent into the first-stage fluorine removal system, and the dosing device of the second-stage fluorine removal system can add PAC and PAM into the second-stage fluorine removal system.

[0017] As a further improvement of the application, a pH detection device and a control system are further arranged, the pH detection device is installed in the fluorine recovery reactor, the pH detection device can detect the pH of the mixed solution in the fluorine recovery reactor in real time, the pH detection device communicates with the control system, and the self-control linkage program of the control system controls the start and stop and flow of the lifting pump of the lime solution according to the pH of the mixed solution.

[0018] The beneficial effects of the present application are: the present application recovers fluorine ions in concentrated acid wastewater in the glass thinning industry by using calcium salt, and leaves most of the silicon and other impurities in the wastewater in the water by pH control mode, and does not enter the calcium fluoride crystal, a small amount of silicon gel in the calcium fluoride crystal is effectively removed by elutriation through the density difference, and a high-purity large-particle calcium fluoride crystal product can be generated, a large amount of fluorine resources are effectively recovered, resource recycling is realized, the disposal cost of the enterprise is reduced, the reagent used in the process of the present application is only lime, etc. Common reagents, the process equipment has high compatibility with the traditional wastewater treatment system of the glass thinning industry, and can be directly modified on the original system, the equipment is simple and easy to operate, the wastewater treatment cost and equipment modification cost are low. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The process flowchart of the present application is shown in the figure.

[0020] The figure legend is as follows: acid water conditioning tank---1; lime dosing tank---2; fluorine recovery reactor---3; primary pressure filtration device---4; secondary pressure filtration device---5; cleaning device---6; fluorine-containing wastewater conditioning tank---7; primary defluorination system---8; secondary defluorination system---9. DETAILED DESCRIPTION

[0021] Example:

[0022] The water quality indicators of the wastewater of a certain glass thinning manufacturer and the purity of the sludge generated by the existing treatment process are as follows: the fluorine ion concentration is 12017 mg / L, the silicon concentration is 2402 mg / L, and the purity of the calcium fluoride sludge obtained by the original treatment process is 58%.

[0023] The glass thinning wastewater adopts the glass thinning wastewater calcium fluoride crystallization process of the present application, and the specific steps are as follows:

[0024] (1) Collect the glass thinning concentrated acid wastewater in the acid water conditioning tank for homogenization, and configure lime solution in the lime dosing tank according to a concentration of 5%-10% by stirring lime solids;

[0025] (2) The lime solution configured in the lime dosing tank and the glass thinning concentrated acid wastewater in the acid water conditioning tank are sent into the fluorine recovery reactor according to a calcium fluoride molar ratio of 0.5-0.6, the self-control linkage program controls the addition amount of sodium hydroxide solution according to the pH of the mixed solution in the fluorine recovery reactor, so that the pH of the mixed solution in the reactor is maintained at 4-5, and the residence time of the mixed solution in the fluorine recovery reactor is controlled at 30-60 minutes. At this time, the fluorine ion content in the effluent of the fluorine recovery reactor is less than 80 ppm, and the silicon content is in the range of 1900-2000 ppm;

[0026] (3) The large particle calcium fluoride crystals with a small amount of silica gel adhered discharged from the fluorine recovery reactor are dewatered by a first pressure filtration device, then washed by pure water in a washing device, and the silica gel on the surface of the large particle calcium fluoride is removed by elutriation. The clean large particle calcium fluoride crystals after washing are dewatered by a second pressure filtration device, and finally the high-quality large particle calcium fluoride crystal product with a purity of more than 85% is obtained;

[0027] (4) The water discharged from the fluorine recovery reactor, the water filtered by the first and second pressure filtration devices, and the washing water of the washing device are collected in a fluorine-containing wastewater conditioning tank. The silicon-containing low-fluorine water is homogenized in the fluorine-containing wastewater conditioning tank. The water quality of the silicon-containing low-fluorine water is generally that the fluoride ion content is below 50 ppm and the suspended solids (SS) concentration is below 300 ppm.

[0028] (5) The silicon-containing low-fluorine water in the fluorine-containing wastewater conditioning tank enters a first fluorine removal system, and calcium chloride is used for fluorine removal, and the calcium fluoride molar ratio is controlled at about 0.5. At this time, the fluoride ion content in the water discharged from the first fluorine removal system is about 10 ppm.

[0029] (6) The water discharged from the first fluorine removal system enters a second fluorine removal system, and PAC and PAM are used for coagulation and sedimentation to remove fluorine. At this time, the water discharged from the second fluorine removal system is clear, the fluoride ion concentration is below 8 ppm, and it meets the discharge standard.

[0030] The glass thinning wastewater treatment equipment for the glass thinning wastewater comprises an acid water adjusting tank 1, a lime dispensing tank 2, a fluorine recovery reactor 3, a primary pressure filtration device 4, a secondary pressure filtration device 5, a cleaning device 6, a fluorine-containing wastewater adjusting tank 7, a two-stage fluorine removal system, a pH detection device and a control system, the acid water adjusting tank 1 is used for containing glass thinning concentrated acid wastewater, the lime dispensing tank 2 is used for dispensing lime solids and water to form a lime solution, the lime dispensing tank 2 is provided with a stirrer, the stirrer can stir the lime solids and water, the acid water adjusting tank 1 and the lime dispensing tank 2 are respectively connected with the water inlet and the medicine inlet of the fluorine recovery reactor 3 through pipelines, the glass thinning concentrated acid wastewater in the acid water adjusting tank 1 and the lime solution in the lime dispensing tank 2 are respectively sent into the fluorine recovery reactor 3 through lifting pumps, the crystal outlet of the fluorine recovery reactor 3 is connected with the inlet of the primary pressure filtration device 4, the primary pressure filtration device 4 can perform pressure filtration dewatering on the large particle calcium fluoride crystals with silicon gel, the solid outlet of the primary pressure filtration device 4 is connected with the inlet of the cleaning device 6, the cleaning device 6 is further provided with a pure water inlet for the pure water, a cleaning water outlet and a solid outlet, the cleaning device 6 can wash the large particle calcium fluoride crystals with silicon gel, the solid outlet of the cleaning device 6 is connected with the inlet of the secondary pressure filtration device 5, the secondary pressure filtration device 5 can perform pressure filtration dewatering on the clean large particle calcium fluoride crystals, the dewatering outlets of the primary pressure filtration device 4 and the secondary pressure filtration device 5, the cleaning water outlet of the cleaning device 6 and the water outlet of the fluorine recovery reactor 3 are connected with the water inlet of the fluorine-containing wastewater adjusting tank 7 through pipelines, the fluorine-containing wastewater adjusting tank 7 is provided with a stirrer, the stirrer in the fluorine-containing wastewater adjusting tank 7 can stir and homogenize various fluorine-containing wastewater, the water outlet of the fluorine-containing wastewater adjusting tank 7 is connected with the two-stage fluorine removal system through a pipeline, the two-stage fluorine removal system comprises a primary fluorine removal system 8 and a secondary fluorine removal system 9 connected through pipelines, the primary fluorine removal system 8 and the secondary fluorine removal system 9 are respectively provided with a dosing device, the dosing device of the primary fluorine removal system 8 can add calcium agent into the primary fluorine removal system 8, the dosing device of the secondary fluorine removal system 9 can add PAC and PAM into the secondary fluorine removal system 9,

[0031] The pH detection device is installed in the fluorine recovery reactor 3, the pH detection device can detect the pH of the mixed solution in the fluorine recovery reactor 3 in real time, the pH detection device communicates with the control system, and the self-control linkage program of the control system controls the start and stop and flow of the lifting pump of the lime solution according to the pH of the mixed solution.

Claims

1. A calcium fluoride crystallization process for glass thinning wastewater, characterized in that: Includes the following steps: Step 1: The concentrated acid wastewater from glass thinning and lime solution are fed into the fluoride recovery reactor at a calcium-fluoride molar ratio of 0.4-0.7, so that the pH of the mixed solution in the fluoride recovery reactor is 4-7. Most of the fluoride in the concentrated acid wastewater from glass thinning undergoes a crystallization reaction in the fluoride recovery reactor to form large-particle calcium fluoride crystals. Most of the silicon in the concentrated acid wastewater from glass thinning enters the two-stage defluorination system with the effluent from the fluoride recovery reactor. A small portion of the silicon in the concentrated acid wastewater from glass thinning forms a network of silica gel. The large-particle calcium fluoride crystals with silica gel adhering to them are discharged from the crystal discharge port of the fluoride recovery reactor. Step 2: The large calcium fluoride crystals with silica gel discharged from the fluoride recovery reactor are washed with pure water. The silica gel on the surface of the large calcium fluoride crystals is removed by hydrodynamic washing through density difference. Then, high-purity large calcium fluoride crystal products are obtained by dehydration. The filtrate and washing water generated from dehydration and washing enter the two-stage defluorination system. Step 3: The first stage of the two-stage defluorination system uses calcium agent to react with low-fluoride water containing silicon. Fluoride ions react with calcium ions to form calcium fluoride precipitate, which is treated as solid waste. The effluent from the first stage defluorination system enters the second stage defluorination system. The second stage defluorination system uses PAC and PAM coagulation and sedimentation to remove suspended solids (SS) and residual fluoride ions from the water. The resulting precipitate is treated as solid waste. The effluent from the second stage defluorination system meets the discharge standards.

2. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step one, the concentrated acid wastewater from glass thinning is collected in an acid water conditioning tank for homogenization, and the lime solution is prepared by mixing lime solids and water in a lime mixing tank at a certain concentration.

3. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step one, a pH detection device is installed in the fluorine recovery reactor to detect the pH of the mixed solution in real time, and the automatic control linkage program controls the amount of lime solution added based on the pH of the mixed solution.

4. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step one, the residence time of the concentrated acid wastewater and lime solution in the fluoride recovery reactor is controlled at 30-60 minutes. More than 90% of the fluoride in the influent of the fluoride recovery reactor grows into large-particle calcium fluoride in the reactor, while 80% of the silicon flows away with the reactor effluent.

5. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: The discharge port of the fluorine recovery reactor is opened periodically to allow large calcium fluoride crystals to be discharged from the reactor regularly and in a measured manner.

6. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step two, the large calcium fluoride crystals coated with silica gel discharged from the fluorine recovery reactor are first dehydrated by a primary filter press, and then washed with pure water to remove the silica gel. The washed large calcium fluoride crystals are then dehydrated by a secondary filter press, finally yielding a high-quality calcium fluoride granular crystal product.

7. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step one, the effluent from the fluoride recovery reactor, as well as the filtrate and washing water produced after dehydration and washing in step two, are directly discharged into the fluoride-containing wastewater equalization tank. The fluoride-containing wastewater equalization tank collects the silicon-containing low-fluoride water and homogenizes it. The silicon-containing low-fluoride water after homogenization treatment in the fluoride-containing wastewater equalization tank enters the two-stage defluorination system for defluorination to meet the standards.

8. The calcium fluoride crystallization process for glass thinning wastewater according to claim 1, characterized in that: In step three, the calcium agent in the primary defluorination system is at least one of calcium hydroxide and calcium chloride.

9. A glass thinning wastewater treatment device used in the calcium fluoride crystallization process of glass thinning wastewater as described in claims 1-8, characterized in that: The system includes an acid water conditioning tank (1), a lime mixing tank (2), a fluoride recovery reactor (3), a primary filter press (4), a secondary filter press (5), a cleaning device (6), a fluoride-containing wastewater conditioning tank (7), and a two-stage defluorination system. The acid water conditioning tank is used to hold concentrated acid wastewater from glass thinning. The lime mixing tank is used to mix lime solids and water to form a lime solution. The lime mixing tank is equipped with a stirrer that can stir the lime solids and water. The acid water conditioning tank and the lime mixing tank are connected by pipes. The system connects to the inlet and outlet of the fluoride recovery reactor. The concentrated acid wastewater from glass thinning in the acid water conditioning tank and the lime solution from the lime preparation tank are pumped into the fluoride recovery reactor via lift pumps. The crystal discharge port of the fluoride recovery reactor is connected to the inlet of a primary filter press, which dehydrates large calcium fluoride crystals coated with silica gel. The solids discharge port of the primary filter press is connected to the inlet of a cleaning device, which also has a pure water inlet, a cleaning water outlet, and a solids discharge port. The cleaning device washes the large calcium fluoride crystals coated with silica gel. The solids discharge port of the cleaning device is connected to the inlet of a secondary filter press, which dehydrates clean large calcium fluoride crystals. The dehydration ports of the primary and secondary filter presses, the cleaning water outlet of the cleaning device, and the outlet of the fluoride recovery reactor are all connected to the inlet of a fluoride-containing wastewater conditioning tank via pipes. The fluoride-containing wastewater conditioning tank is equipped with a stirrer. The agitator can mix and homogenize various fluoride-containing wastewaters entering the fluoride-containing wastewater equalization tank. The outlet of the fluoride-containing wastewater equalization tank is connected to a two-stage defluorination system through a pipeline. The two-stage defluorination system includes a primary defluorination system (8) and a secondary defluorination system (9) connected sequentially through pipelines. The primary defluorination system and the secondary defluorination system are respectively equipped with dosing devices. The dosing device of the primary defluorination system can add calcium agent to the primary defluorination system, and the dosing device of the secondary defluorination system can add PAC and PAM to the secondary defluorination system.

10. The glass thinning wastewater treatment equipment according to claim 9, characterized in that: It is also equipped with a pH detection device and a control system. The pH detection device is installed in the fluorine recovery reactor. The pH detection device can detect the pH of the mixed solution in the fluorine recovery reactor in real time. The pH detection device communicates with the control system. The automatic control linkage program of the control system controls the start and stop of the lime solution booster pump and the flow rate according to the pH of the mixed solution.

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