Combined acid fluoride wastewater lime crystallization tower device

Abstract

The utility model discloses a combined acid fluoride wastewater lime crystallization tower device, which is characterized in that a reactor sequentially forms a mixing area, a first-stage defluorination area, a second-stage defluorination area and a water outlet area from bottom to top, an acid fluoride wastewater inlet system can feed acid fluoride wastewater into the mixing area of the reactor, and a lime dosing system can feed a lime medicament into a lime diluting device for dilution; the lime diluting device can feed diluted lime water into the mixing area of the reactor, and the calcium chloride dosing system can add a calcium chloride agent into the reactor to enable the calcium chloride agent and the wastewater subjected to the primary defluorination reaction to be subjected to secondary defluorination reaction; the reflux dilution system can feed water subjected to defluorination in the second-stage defluorination area in the reactor into the lime dilution device for diluting a lime agent, calcium fluoride crystals generated by reaction in the reactor are discharged through a crystal discharge pipeline at the lower end of the reactor, produced water in the water outlet area is discharged through a water outlet pipe, and the controller controls all the systems to work. The device disclosed by the utility model realizes the recovery of high-quality calcium fluoride resources while ensuring the fluorine removal effect of the wastewater.

Description

Technical Field

[0001] The utility model relates to a wastewater treatment technology, in particular to a combined acid-fluorine wastewater lime crystallization tower device. Background Art

[0002] In the photovoltaic and semiconductor industries, calcium defluoridation is usually used to remove fluoride from acid fluoride wastewater. There are currently two main ways to treat it:

[0003] One is a chemical precipitation treatment process, which uses lime solution combined with calcium chloride to remove fluoride from water. Lime mainly plays the role of acid-base neutralization and provides a partial calcium source to generate calcium fluoride;

[0004] The other method is to use a chemical crystallization process, which uses liquid alkali combined with calcium chloride to form chemical crystals with fluoride in water.

[0005] There are two ways to get rid of the calcium fluoride produced in the reaction:

[0006] One method is to dispose of chemical sludge after it is formed. The chemical sludge has a high moisture content (40%-70%), which increases the cost of sludge treatment.

[0007] The other is to form calcium fluoride crystals for recycling, which can generate significant economic value.

[0008] One of the more promising technologies is to recover fluoride ions from water by crystallization. However, this technology cannot be widely used because the cost of liquid alkali as a neutralizing agent is too high.

[0009] Lime has a low cost and can not only provide the alkali required for neutralization, but also provide a source of calcium, but the current technology using lime crystallization is relatively immature.

[0010] The main difficulties of using lime as a neutralizer in the crystallization technology of acidic fluoride-containing water are as follows:

[0011] 1. Lime cannot be fully dissolved, which not only leads to an excessively high dosage ratio, but also the calcium hydroxide impurities in the crystals greatly reduce the purity of calcium fluoride crystals;

[0012] 2. Lime dissolution requires a large amount of dilution water, and the dilution water has high requirements for fluoride ion concentration and carbonate ion concentration;

[0013] 3. The alkalinity slowly released during the lime dissolution process will affect the pH control of crystallization, resulting in unstable pH control of mixed water during the crystallization reaction, which is not conducive to the crystallization reaction. Utility Model Content

[0014] In order to overcome the above-mentioned defects, the utility model provides a combined acid-fluoride wastewater lime crystallization tower device, which can effectively solve the problems of difficult lime dissolution, unstable pH control and high requirements for dilution water quality for lime dissolution, while ensuring the defluorination effect, realizing the recovery of high-quality calcium fluoride resources.

[0015] The utility model adopts a technical solution to solve the technical problem: a combined acid-fluorine wastewater lime crystallization tower device, comprising a reactor, a lime dosing system, a lime dilution device, a reflux dilution system, an acid-fluorine wastewater inlet system, a calcium chloride dosing system, a water outlet pipeline, a crystal row pipeline and a controller, wherein the reactor sequentially forms a mixing zone, a primary defluorination zone, a secondary defluorination zone and a water outlet zone from bottom to top, the lime dosing system can provide lime reagent to the lime dilution device, the reflux dilution system can send the water in the reactor that has been defluorinated in the secondary defluorination zone into the lime dilution device for diluting the lime reagent, and the lime dilution device can dilute the diluted water. Lime water is fed into a mixing zone of a reactor, an acid-fluoride wastewater inlet system can feed the acid-fluoride wastewater to be treated into the mixing zone of the reactor to be mixed with lime water, a calcium chloride dosing system can add calcium chloride agent into the reactor, so that the calcium chloride agent and the wastewater after the primary defluorination reaction undergo a secondary defluorination reaction, an outlet pipe is arranged on the side wall of the upper end of the reactor, the outlet pipe is connected with the outlet zone to discharge water outward, a crystal discharge pipe is arranged at the lower end of the reactor, and the discharge pipe can discharge calcium fluoride crystals generated by the defluorination reaction, and a controller can control the start and stop of the lime dosing system, the reflux dilution system, the acid-fluoride wastewater inlet system and the calcium chloride dosing system.

[0016] As a further improvement of the utility model, a lime water inlet, an acid fluoride wastewater inlet and a calcium chloride dosing port are respectively provided on the side wall of the reactor, the lime water inlet and the acid fluoride wastewater inlet are both correspondingly connected to the mixing zone in the reactor, and the height of the acid fluoride wastewater inlet is higher than that of the lime water inlet, and the calcium chloride dosing port is located at the junction of the primary defluorination zone and the secondary defluorination zone.

[0017] As a further improvement of the utility model, the lime dilution device is a mixing and dilution tube, one end of which is connected to the lime water inlet on the side wall of the reactor, the lime dosing system includes a lime emulsion tank, a lime dosing tube and a lime dosing pump, the lime emulsion tank is connected to the other end of the mixing and dilution tube through the lime dosing tube, and the lime dosing pump can quantitatively pump the lime emulsion in the lime emulsion tank into the other end of the mixing and dilution tube, the reflux dilution system includes a reflux pipeline and a reflux pump, one end of the reflux pipeline is connected to the water outlet area or the upper end of the secondary defluorination area in the reactor, and the other end of the reflux pipeline is connected to the other end of the mixing and dilution tube, the reflux pump can quantitatively pump the water defluorinated in the secondary defluorination area into the other end of the mixing and dilution tube through the reflux pipeline, the lime emulsion and the reflux water refluxed through the reflux pipeline can be mixed and diluted while flowing together in the mixing and dilution tube, and the controller controls the operation of the lime dosing pump and the reflux pump.

[0018] As a further improvement of the utility model, a water outlet weir is provided in the water outlet area of ​​the reactor, and the inlet of the reflux pipeline is located on the side wall of the reactor between the calcium chloride dosing port and the water outlet weir.

[0019] As a further improvement of the utility model, the acid-fluorine wastewater inlet system includes an acid-fluorine wastewater collection tank, an acid-fluorine wastewater inlet pipe and an acid-fluorine wastewater inlet pump, one end of the acid-fluorine wastewater inlet pipe is connected to the acid-fluorine wastewater collection tank, and the other end of the acid-fluorine wastewater inlet pipe is connected to the acid-fluorine wastewater inlet, the acid-fluorine wastewater inlet pump can quantitatively pump the acid-fluorine wastewater in the acid-fluorine wastewater collection tank into the acid-fluorine wastewater inlet, and the controller controls the operation of the acid-fluorine wastewater inlet pump.

[0020] As a further improvement of the utility model, the calcium chloride dosing system includes a calcium chloride dosing tank, a calcium chloride dosing pipe and a calcium chloride dosing pump, one end of the calcium chloride dosing pipe is connected to the calcium chloride dosing tank, and the other end of the calcium chloride dosing pipe is connected to the calcium chloride dosing port. The calcium chloride dosing pump can quantitatively inject the calcium chloride agent stored in the calcium chloride dosing tank into the calcium chloride dosing port, and the controller controls the operation of the calcium chloride dosing pump.

[0021] As a further improvement of the utility model, a lime water inlet distributor, an acid fluoride wastewater inlet distributor and a calcium chloride inlet distributor are fixedly installed inside the reactor, and the water inlets of the lime water inlet distributor, the acid fluoride wastewater inlet distributor and the calcium chloride inlet distributor are respectively connected to the lime water inlet, the acid fluoride wastewater inlet and the calcium chloride dosing port, and the lime water inlet distributor, the acid fluoride wastewater inlet distributor and the calcium chloride water inlet distributor are respectively provided with a plurality of evenly spaced water distribution ports, and the water distribution ports on the lime water inlet distributor, the acid fluoride wastewater inlet distributor and the calcium chloride inlet distributor are respectively used for evenly distributing lime water, acid fluoride wastewater and calcium chloride.

[0022] As a further improvement of the utility model, the upper water distribution ports of the lime water inlet distributor, the acid fluoride wastewater inlet distributor and the calcium chloride inlet distributor all discharge water downward.

[0023] As a further improvement of the utility model, a lime dosing flowmeter, a reflux water flowmeter, an acid fluoride wastewater inlet flowmeter and a calcium chloride dosing flowmeter are further provided. The lime dosing flowmeter can detect the flow rate of lime reagent added by the lime dosing system to the lime dilution device, the reflux water flowmeter can detect the flow rate of reflux water sent by the reflux dilution system to the lime dilution device, the acid fluoride wastewater inlet flowmeter can detect the flow rate of acid fluoride wastewater sent by the acid fluoride wastewater inlet system to the mixing zone, and the calcium chloride dosing flowmeter can detect the flow rate of calcium chloride reagent added by the calcium chloride dosing system into the reactor. The lime dosing flowmeter, the reflux water flowmeter, the acid fluoride wastewater inlet flowmeter and the calcium chloride dosing flowmeter communicate with the controller respectively.

[0024] As a further improvement of the utility model, the lime dosing system, the reflux dilution system, the acid fluoride wastewater inlet system, the calcium chloride dosing system and the crystal row pipeline are all provided with control valves, and the controller controls the opening and closing of each control valve.

[0025] The beneficial effects of the utility model are as follows: the reactor of the utility model is provided with a reflux mixing zone, a primary defluorination zone, a secondary defluorination zone and a water outlet zone from bottom to top, and the defluorinated water is refluxed as lime dilution water by providing a reflux dilution system, so that the water distribution demand of lime water can be guaranteed, and a large amount of water resources can be saved; the reflux water for dilution is mixed with the prepared lime emulsion and then enters the mixing zone at the bottom of the reactor, so that the calcium hydroxide can be fully dissolved, and the problem of the difficulty in dissolving lime is solved; the reflux mixed liquid with the lime dissolved is contacted with the acid-fluoride wastewater, and the hydroxide ions and calcium ions in the mixed liquid in an ionic state can respectively play the role of neutralizing the hydrogen ions in the acid-fluoride wastewater and crystallizing the defluorination, and the hydrogen ions in the acid-fluoride wastewater are neutralized by the hydroxide ions in the mixed liquid. and, so that the solution becomes neutral, and at the same time, the fluoride ions in the acid-fluoride wastewater react with the calcium ions in the mixed solution to form calcium fluoride crystals, thereby ensuring the effective use of lime, reducing the amount of lime used, and keeping the pH in the crystallization tower stable, effectively improving the purity of the calcium fluoride crystals. The utility model is also provided with a secondary defluorination zone and a calcium chloride dosing system, so that the fluoride ions in the effluent are maintained at a low level, ensuring the fluoride removal effect of the effluent, and at the same time ensuring that the fluoride ions and carbonate ions in the reflux water used to dilute the lime meet the requirements, thereby effectively preventing the reflux water from reacting with calcium hydroxide for precipitation when used as lime preparation dilution water, thereby ensuring the quality of the lime water, ensuring that the lime water and the acid-fluoride wastewater undergo sufficient crystallization reaction in the reactor, and maintaining the stable operation of the crystallization tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1It is a schematic diagram of the structural principle of the utility model. DETAILED DESCRIPTION

[0027] Embodiment: A combined acid-fluoride wastewater lime crystallization tower device comprises a reactor. The interior of the reactor 1 of the combined crystallization tower is divided into a mixing zone, a primary defluorination zone, a secondary defluorination zone and a water outlet zone from bottom to top, and is equipped with an acid-fluoride wastewater inlet system, a lime dosing system, a calcium chloride dosing system, a water outlet pipe, a reflux dilution system and a crystal discharge pipe.

[0028] The reactor 1 is provided with a lime water inlet distributor 7, an acid fluoride waste water inlet distributor 12 and a calcium chloride inlet distributor 17 in sequence from bottom to top.

[0029] The mixing and dilution pipe 6 is connected to the limewater inlet distributor 7. The lime emulsion tank 2 is connected to the mixing and dilution pipe 6 through the lime dosing pipe 5, and the lime dosing pipe 5 is provided with a lime dosing pump 3 and a lime dosing flowmeter 4.

[0030] The acid-fluorine wastewater collection pool 8 is connected to the acid-fluorine wastewater inlet distributor 12 via the acid-fluorine wastewater inlet pipe 11 , and the acid-fluorine wastewater inlet pipe 11 is provided with an acid-fluorine wastewater inlet pump 9 and an acid-fluorine wastewater feed flowmeter 10 .

[0031] The calcium chloride dosing tank 13 is connected to a calcium chloride water inlet distributor 17 via a calcium chloride dosing pipe 16 , and the calcium chloride dosing pipe 16 is provided with a calcium chloride dosing pump 14 and a calcium chloride dosing flowmeter 15 .

[0032] The inlet of the reflux pipeline 20 is located between the calcium chloride water inlet distributor 17 and the outlet weir 21, and the outlet of the reflux pipeline 20 is connected to the mixing and dilution pipe 6. The reflux pipeline 20 is provided with a reflux pump 18 and a reflux liquid flowmeter 19. The outlet weir 21 is provided with an outlet pipe 22.

[0033] The reflux pipe 20 is used to provide reflux of the effluent from the secondary defluorination zone, which can provide water for diluting the lime and ensure the flow rate in the crystallization tower.

[0034] A crystal discharge pipeline 23 is provided at the bottom of the reactor 1 of the combined crystallization tower.

[0035] All the above pipelines are equipped with valves.

[0036] During operation, the reflux is turned on to make the reactor 1 of the combined crystallization tower in a fluidized state. The acid fluoride wastewater in the acid fluoride wastewater collection pool is pumped by the acid fluoride wastewater inlet pump at a certain flow rate along the acid fluoride wastewater inlet pipe and through the acid fluoride wastewater inlet distributor into the reactor of the combined crystallization tower.

[0037] At the same time, the lime dosing is turned on. The lime emulsion in the lime emulsion tank enters the mixing and dilution pipe through the lime dosing pump at a certain flow rate along the lime dosing pipe, and enters the mixing and dilution water distributor at the bottom of the combined crystallization tower after mixing with the reflux liquid in the mixing and dilution pipe and enters the bottom mixing area, so that the lime component is fully dissolved therein. The dissolved mixed solution is then mixed with the acid fluoride wastewater entering the combined crystallization tower. In the primary defluorination area, a neutralization reaction and a chemical precipitation reaction occur simultaneously. The hydrogen ions in the acid fluoride wastewater are neutralized by the hydroxide ions in the mixed solution, making the solution neutral. At the same time, the fluorine in the acid fluoride wastewater reacts with the calcium in the mixed solution to form calcium fluoride crystals. The mixed solution after partial defluorination continues to contact and react with the calcium chloride solution entering the calcium chloride dosing system during the rising process. In the secondary defluorination area, the calcium ions in the calcium chloride react with the fluoride ions in the water to further reduce the fluorine concentration in the water. A part of the solution after the secondary defluorination forms a reflux dilution liquid, and the other part enters the outlet area and is discharged through the outlet pipe set on the outlet weir at the top of the outlet area, thereby completing the treatment process of the acid fluoride wastewater. After running for a certain period of time, the large-particle seed crystals produced are discharged from the bottom crystal discharge tube.

Claims

1. A combined acid-fluorine wastewater lime crystallization tower device, characterized in that: The invention comprises a reactor (1), a lime dosing system, a lime dilution device, a reflux dilution system, an acid fluoride wastewater inlet system, a calcium chloride dosing system, a water outlet pipe (22), a crystal row pipe (23) and a controller. The reactor is sequentially formed with a mixing zone, a primary defluorination zone, a secondary defluorination zone and a water outlet zone from bottom to top. The lime dosing system can provide lime reagent to the lime dilution device. The reflux dilution system can send the water in the reactor that has been defluorinated in the secondary defluorination zone to the lime dilution device for diluting the lime reagent. The lime dilution device can send the diluted lime water to the mixing zone of the reactor. The acid-fluoride wastewater inlet system can deliver the acid-fluoride wastewater to be treated into the mixing zone of the reactor to be mixed with lime water. The calcium chloride dosing system can add calcium chloride agent into the reactor, so that the calcium chloride agent and the wastewater after the primary defluorination reaction undergo a secondary defluorination reaction. The outlet pipe is arranged on the upper side wall of the reactor, the outlet pipe is connected to the outlet zone to drain water outward, the crystal discharge pipe is arranged at the lower end of the reactor, and the discharge pipe can discharge the calcium fluoride crystals produced by the defluorination reaction. The controller can control the start and stop of the lime dosing system, the reflux dilution system, the acid-fluoride wastewater inlet system and the calcium chloride dosing system.

2. The combined acid-fluorine wastewater lime crystallization tower device according to claim 1, characterized in that: A lime water inlet, an acid fluoride wastewater inlet and a calcium chloride dosing port are respectively arranged on the side wall of the reactor. The lime water inlet and the acid fluoride wastewater inlet are both correspondingly connected to the mixing zone in the reactor, and the height of the acid fluoride wastewater inlet is higher than that of the lime water inlet. The calcium chloride dosing port is located at the junction of the primary defluorination zone and the secondary defluorination zone.

3. The combined acid-fluorine wastewater lime crystallization tower device according to claim 2 is characterized in that: The lime dilution device is a mixing and dilution pipe (6), one end of which is connected to the lime water inlet on the side wall of the reactor. The lime dosing system comprises a lime emulsion tank (2), a lime dosing pipe (5) and a lime dosing pump (3). The lime emulsion tank is connected to the other end of the mixing and dilution pipe through the lime dosing pipe. The lime dosing pump can quantitatively pump the lime emulsion in the lime emulsion tank into the other end of the mixing and dilution pipe. The reflux dilution system comprises a reflux pipeline (20) and a reflux pump (18). One end of the reflux pipeline is connected to the water outlet area or the upper end of the secondary defluorination area in the reactor, and the other end of the reflux pipeline is connected to the other end of the mixing and dilution pipe. The reflux pump can quantitatively pump the water defluorinated in the secondary defluorination area into the other end of the mixing and dilution pipe through the reflux pipeline. The lime emulsion and the reflux water refluxed through the reflux pipeline can flow together in the mixing and dilution pipe and be mixed and diluted. The controller controls the operation of the lime dosing pump and the reflux pump.

4. The combined acid-fluorine wastewater lime crystallization tower device according to claim 3 is characterized in that: A water outlet weir (21) is provided in the water outlet area of ​​the reactor, and the inlet of the reflux pipeline is located on the side wall of the reactor between the calcium chloride dosing port and the water outlet weir (21).

5. The combined acid-fluorine wastewater lime crystallization tower device according to claim 2, characterized in that: The acid-fluorine wastewater inlet system comprises an acid-fluorine wastewater collection tank (8), an acid-fluorine wastewater inlet pipe (11) and an acid-fluorine wastewater inlet pump (9), one end of the acid-fluorine wastewater inlet pipe is connected to the acid-fluorine wastewater collection tank, and the other end of the acid-fluorine wastewater inlet pipe is connected to the acid-fluorine wastewater inlet, the acid-fluorine wastewater inlet pump can quantitatively pump the acid-fluorine wastewater in the acid-fluorine wastewater collection tank into the acid-fluorine wastewater inlet, and the controller controls the operation of the acid-fluorine wastewater inlet pump.

6. The combined acid-fluorine wastewater lime crystallization tower device according to claim 2, characterized in that: The calcium chloride dosing system comprises a calcium chloride dosing tank (13), a calcium chloride dosing pipe (16) and a calcium chloride dosing pump (14), one end of the calcium chloride dosing pipe is connected to the calcium chloride dosing tank, and the other end of the calcium chloride dosing pipe is connected to a calcium chloride dosing port. The calcium chloride dosing pump can quantitatively inject the calcium chloride agent stored in the calcium chloride dosing tank into the calcium chloride dosing port, and a controller controls the operation of the calcium chloride dosing pump.

7. The combined acid-fluorine wastewater lime crystallization tower device according to claim 2, characterized in that: A limewater inlet distributor (7), an acid-fluorine wastewater inlet distributor (12) and a calcium chloride inlet distributor (17) are fixedly installed inside the reactor. The water inlets of the limewater inlet distributor, the acid-fluorine wastewater inlet distributor and the calcium chloride inlet distributor are respectively connected to the limewater inlet, the acid-fluorine wastewater inlet and the calcium chloride dosing port. The limewater inlet distributor, the acid-fluorine wastewater inlet distributor and the calcium chloride inlet distributor are respectively provided with a plurality of evenly spaced water distribution ports. The water distribution ports on the limewater inlet distributor, the acid-fluorine wastewater inlet distributor and the calcium chloride inlet distributor are respectively used to evenly distribute the limewater, the acid-fluorine wastewater and the calcium chloride.

8. The combined acid-fluorine wastewater lime crystallization tower device according to claim 7, characterized in that: The water distribution ports on the limewater inlet distributor, the acid-fluoride wastewater inlet distributor and the calcium chloride inlet distributor all discharge water downwards.

9. The combined acid-fluorine wastewater lime crystallization tower device according to claim 1, characterized in that: A lime dosing flowmeter (4), a reflux water flowmeter (19), an acid fluoride wastewater inlet flowmeter (10) and a calcium chloride dosing flowmeter (15) are also provided. The lime dosing flowmeter can detect the flow rate of lime reagent added by the lime dosing system to the lime dilution device, the reflux water flowmeter can detect the flow rate of reflux water sent by the reflux dilution system to the lime dilution device, the acid fluoride wastewater inlet flowmeter can detect the flow rate of acid fluoride wastewater sent by the acid fluoride wastewater inlet system to the mixing zone, and the calcium chloride dosing flowmeter can detect the flow rate of calcium chloride reagent added by the calcium chloride dosing system to the reactor. The lime dosing flowmeter, the reflux water flowmeter, the acid fluoride wastewater inlet flowmeter and the calcium chloride dosing flowmeter communicate with the controller respectively.

10. The combined acid-fluorine wastewater lime crystallization tower device according to claim 1, characterized in that: The lime dosing system, the reflux dilution system, the acid-fluorine wastewater inlet system, the calcium chloride dosing system and the crystal row pipeline are all provided with control valves, and the controller controls the opening and closing of each control valve.

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