Glass fiber production waste gas treatment device and process

Abstract

The present invention belongs to the technical field of waste gas treatment in glass fiber production, and specifically relates to a device and process for treating waste gas in glass fiber production. The device includes a stirring reaction tank, a sedimentation tank, a mud press, a water storage tank, a first crystallization tank, a first heat exchanger, a second crystallization tank, and a second heat exchanger. The present invention can treat waste water from spraying and adsorbing waste gas, and respectively extract calcium fluoride, sodium borate, and sodium sulfate. These three raw materials are all raw materials in glass formulas, and can be directly mixed into batch materials in a certain proportion and directly returned to the kiln for reuse in production, forming resources and saving production costs. The present invention can separate solid waste during sewage treatment, which is beneficial to the subsequent sewage treatment process. The present invention can reintroduce the treated sewage into the waste gas sewage pool as an adsorbent for the spray tower, so that the sewage can be recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of waste gas treatment in glass fiber production, and specifically relates to a device and process for treating waste gas in glass fiber production. Background Art

[0002] The waste gas from the glass and glass fiber industry contains a large amount of sulfur, boron, fluorine and other elements. Dry or wet desulfurization technology is often used to absorb and treat the waste gas with alkaline substances. However, the main problem with the current treatment method is that the wastewater after the spray tower absorbs the waste gas contains a large amount of waste (including sulfur, boron, fluorine, etc.). This type of waste is a mixture with large changes in composition and cannot be effectively utilized, causing secondary pollution. It is also difficult to dispose of subsequent wastewater treatment, which greatly increases the difficulty and cost of wastewater treatment. Summary of the invention

[0003] In view of the above technical problems, the purpose of the present invention is to provide a glass fiber production waste gas treatment device and process, which solves the technical problems of waste of resources, difficult waste treatment, and high sewage treatment cost in the prior art.

[0004] The glass fiber production waste gas treatment device of the present invention comprises a spray tower, which is connected to a circulating water pool for storing an adsorbent, and also comprises a stirred reaction tank, a sedimentation tank, a mud press, a water storage tank, a first crystallization tank, a first heat exchanger, a second crystallization tank, and a second heat exchanger; a first circulating water pipe and a second circulating water pipe are respectively arranged between the upper and bottom ends of the first crystallization tank and the second crystallization tank, and the first circulating water pipe and the second circulating water pipe are respectively provided with a first heat exchanger and a second heat exchanger, the bottom of the first crystallization tank is connected to the first storage tank through a first discharge pipe, the first discharge pipe is provided with a first centrifuge, the first centrifuge is also connected to the second circulating water pipe above the second heat exchanger through a sixth pipeline, and the second crystallization tank The bottom is connected to the second storage tank through the second discharge pipe, the second discharge pipe is provided with a second centrifuge, and the second centrifuge is also connected to the circulating water tank through the eighth pipeline; the circulating water tank is connected to the stirred reaction tank through the first pipeline, the stirred reaction tank is connected to the sedimentation tank through the second pipeline, the sedimentation tank is connected to the water storage tank through the third pipeline, the bottom of the sedimentation tank is connected to the mud press through the eleventh pipeline, the water storage tank is connected to the first circulating water pipe above the first heat exchanger through the fourth pipeline, the first crystallizer is connected to the first thickener through the fifth pipeline, the first thickener is connected to the sixth pipeline through the ninth pipeline, the second crystallizer is connected to the second thickener through the seventh pipeline, and the second thickener is connected to the eighth pipeline through the tenth pipeline;

[0005] Among them: the second pipeline is provided with a lifting pump, the eleventh pipeline is provided with a first screw pump, the fourth pipeline is provided with a first feed pump, the first circulating water pipe is provided with a first axial flow circulating pump, the fifth pipeline is provided with a first crystal material discharge pump, the sixth pipeline is provided with a second feed pump, the second circulating water pipe is provided with a second axial flow circulating pump, the seventh pipeline is provided with a second crystal material discharge pump, the eighth pipeline is provided with a third feed pump, and the first pipeline is provided with a circulating water pump.

[0006] A silo is provided next to the stirred reactor, and an electronic scale is provided directly below the silo.

[0007] The bottom of the water storage tank is connected with the mud press through the twelfth pipeline, and the twelfth pipeline is provided with a second screw pump.

[0008] The glass fiber production waste gas treatment process of the present invention comprises the following steps:

[0009] (1) The wastewater from the waste gas is absorbed by the spray tower and enters the circulating water pool. The wastewater in the circulating water pool is introduced into the spray tower and recycled as an adsorbent to replenish alkali in the wastewater in the circulating water pool;

[0010] (2) introducing the sewage in the circulating water pool into a stirred reaction tank, adding a defluorinating agent, stirring and defluorinating, and introducing it into a sedimentation tank after defluorinating. After sedimentation, the upper clear liquid in the sedimentation tank is introduced into a water storage tank for temporary storage, and the sediment at the bottom of the sedimentation tank is pumped into a mud press for mud pressing;

[0011] (3) introducing the sewage in the water storage tank into the first crystallizer, opening the first heat exchanger to control the sewage temperature, so that sodium borate crystals are precipitated, pumping the mixed liquid in the first crystallizer into the first thickener for concentration, the concentrated slurry enters the first centrifuge, the sodium borate crystals separated by the first centrifuge enter the first storage tank for storage, and the supernatant liquid of the first thickener and the sewage separated by the first centrifuge enter the second crystallizer;

[0012] (4) The second heat exchanger is turned on to control the sewage temperature so that sodium sulfate crystals are precipitated, and the mixed liquid in the second crystallizer is pumped into the second thickener for concentration. The concentrated slurry enters the second centrifuge, and the sodium sulfate crystals separated by the second centrifuge are stored in the second storage tank. The supernatant liquid of the second thickener and the sewage separated by the second centrifuge are recycled into the circulating water pool.

[0013] The alkali solution in step (1) is one or more of sodium hydroxide solution, sodium carbonate solution and sodium bicarbonate solution, which is related to the sodium content in the sodium borate and sodium sulfate proposed in the subsequent process, and its main purpose is to maintain the sodium ion balance of the whole system.

[0014] In step (2), the defluorinating agent is one or more of calcium hydroxide, calcium carbonate or calcium oxide.

[0015] The defluorination process in step (2) is as follows: adjusting pH to 6-7, reaction temperature to 25-45° C., and reaction time to 10-60 min.

[0016] In step (3), the sewage temperature is controlled to be 10-18°C.

[0017] In step (4), the sewage temperature is controlled to be 1-7°C.

[0018] The sediment at the bottom of the water storage tank (1) is pumped into a mud compactor for mud compaction treatment.

[0019] Compared with the prior art, the present invention has the following beneficial effects.

[0020] (1) The present invention can process the wastewater from the spraying and adsorption of waste gas, and respectively extract calcium fluoride, sodium borate and sodium sulfate. These three raw materials are all raw materials in the glass formula, and can be directly mixed into batch materials according to a certain proportion and directly returned to the kiln for reuse in production, thus forming resources and saving production costs;

[0021] (2) The present invention can separate solid waste during sewage treatment, which is beneficial to the subsequent sewage treatment process;

[0022] (3) The present invention can reintroduce the treated sewage into the waste gas sewage pool as an adsorbent for the spray tower, so that the sewage can be recycled.

[0023] The present invention is also applicable to the treatment of waste gas absorption liquid in the glass production industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural diagram of Example 1 of the present invention.

[0025] In the figure: 1, water storage tank 2, third pipeline 3, sedimentation tank 4, second pipeline 5, silo 6, electronic scale 7, circulating water tank 8, eighth pipeline 9, third feed pump 10, circulating water pump 11, tenth pipeline 12, second thickener 13, seventh pipeline 14, second crystallizer 15, second crystal material discharge pump 16, second axial flow circulation pump 17, second centrifuge 18, second storage tank 19, second discharge pipe 20, second heat exchanger 21, second circulating water pipe 22, second feed pump 23, sixth pipeline 24, the ninth pipeline 25, the first thickener 26, the first centrifuge 27, the fifth pipeline 28, the first storage tank 29, the first discharge pipe 30, the first crystal material discharge pump 31, the first axial flow circulation pump 32, the first circulation water pipe 33, the first feed pump 34, the first heat exchanger 35, the first crystallization tank 36, the fourth pipeline 37, the twelfth pipeline 38, the second screw pump 39, the mud press 40, the first screw pump 41, the eleventh pipeline 42, the lifting pump 43, the stirred reaction tank 44, the first pipeline. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the embodiments and the accompanying drawings.

[0027] Example 1

[0028] like Figure 1As shown, the glass fiber production waste gas treatment device of the present invention includes a spray tower, which is connected to a circulating water pool 7 for storing an adsorbent, and also includes a stirred reaction tank 43, a precipitation tank 3, a mud press 39, a water storage tank 1, a first crystallization tank 35, a first heat exchanger 34, a second crystallization tank 14, and a second heat exchanger 20; a first circulating water pipe 32 and a second circulating water pipe 21 are respectively provided between the upper and bottom ends of the first crystallization tank 35 and the second crystallization tank 14, and the first circulating water pipe 32 and the second circulating water pipe 21 are respectively provided with the first heat exchanger 34 and the second heat exchanger 20, the bottom of the first crystallization tank 35 is connected to the first storage tank 28 through a first discharge pipe 29, and the first discharge pipe 29 is provided with a first centrifuge 26, and the first centrifuge 26 is also connected to the second circulating water pipe 21 above the second heat exchanger 20 through a sixth pipeline 23, and the bottom of the second crystallization tank 14 is connected to the second storage tank 28 through a first discharge pipe 29. The second discharge pipe 19 is connected to the second storage tank 18, and the second discharge pipe 19 is provided with a second centrifuge 17, and the second centrifuge 17 is also connected to the circulating water pool 7 through the eighth pipeline 8; the circulating water pool 7 is connected to the stirring reaction tank 43 through the first pipeline 44, the stirring reaction tank 43 is connected to the precipitation tank 3 through the second pipeline 4, the precipitation tank 3 is connected to the water storage tank 1 through the third pipeline 2, the bottom of the precipitation tank 3 is connected to the mud press 39 through the eleventh pipeline 41, the water storage tank 1 is connected to the first circulating water pipe 32 above the first heat exchanger 34 through the fourth pipeline 36, the first crystallizer 35 is connected to the first thickener 25 through the fifth pipeline 27, the first thickener 25 is connected to the sixth pipeline 23 through the ninth pipeline 24, the second crystallizer 14 is connected to the second thickener 12 through the seventh pipeline 13, and the second thickener 12 is connected to the eighth pipeline 8 through the tenth pipeline 11;

[0029] Among them: the second pipeline 4 is provided with a lifting pump 42, the eleventh pipeline 41 is provided with a first screw pump 40, the fourth pipeline 36 is provided with a first feed pump 33, the first circulating water pipe 32 is provided with a first axial flow circulating pump 31, the fifth pipeline 27 is provided with a first crystal material discharge pump 30, the sixth pipeline 23 is provided with a second feed pump 22, the second circulating water pipe 21 is provided with a second axial flow circulating pump 16, the seventh pipeline 13 is provided with a second crystal material discharge pump 15, the eighth pipeline 8 is provided with a third feed pump 9, and the first pipeline 44 is provided with a circulating water pump 10.

[0030] A silo 5 is provided beside the stirring reaction tank 43 , and an electronic scale 6 is provided directly below the silo 5 .

[0031] The bottom of the water storage tank 1 is connected to a mud press 39 via a twelfth pipeline 37 , and a second screw pump 38 is provided on the twelfth pipeline 37 .

[0032] Example 2

[0033] The glass fiber production waste gas treatment process of the present invention comprises the following steps:

[0034] (1) The wastewater from the waste gas absorbed by the spray tower enters the circulating water pool 7, and the wastewater in the circulating water pool 7 is introduced into the spray tower for recycling as an adsorbent to supplement alkali in the wastewater in the circulating water pool 7;

[0035] (2) The sewage in the circulating water pool 7 is introduced into the stirring reaction tank 43, and high-quality calcium hydroxide is added into the water body. The added quality is confirmed according to the fluorine content in the water, and the pH value of the reaction slurry is controlled to be between 6 and 7. The reaction is stirred in the stirring reaction tank 43 for 45 minutes, and the stirring reaction temperature is 35° C. After the reaction is completed, it is pumped into the precipitation tank 3 for precipitation. After the precipitation is complete, the upper clear liquid in the precipitation tank 3 is introduced into the water storage tank 1 for temporary storage. The precipitation at the bottom of the precipitation tank 3 is pumped into the mud press 39 by a wear-resistant mortar pump for mud pressing treatment to obtain white mud (calcium fluoride);

[0036] (3) introducing the sewage in the water storage tank 1 into the first crystallizer 35, opening the first heat exchanger 34 to control the sewage temperature, controlling the sewage temperature to 15° C., allowing sodium borate to crystallize, pumping the mixed solution in the first crystallizer 35 into the first thickener 25 for concentration, and the concentrated slurry enters the first centrifuge 26. The sodium borate crystals separated by the first centrifuge 26 enter the first storage tank 28 for storage, and the supernatant liquid in the first thickener 25 and the sewage separated by the first centrifuge 26 enter the second crystallizer 14;

[0037] (4) The second heat exchanger 20 is turned on to control the sewage temperature, and the sewage temperature is controlled to be 5° C. to allow sodium sulfate to crystallize and precipitate. The mixed liquid in the second crystallizer 14 is pumped into the second thickener 12 for concentration, and the concentrated slurry enters the second centrifuge 17. The sodium sulfate crystals separated by the second centrifuge 17 enter the second storage tank 18 for storage, and the supernatant liquid in the second thickener 12 and the sewage separated by the second centrifuge 17 enter the circulating water tank 7 for recycling.

[0038] In step (1), the alkali is a 33% sodium hydroxide solution, and the amount of alkali supplement is 2-3m 3 / d.

[0039] The water sample test data in the sewage treatment of this embodiment is shown in Table 1, and the defluorination white mud and crystallization product test data are shown in Table 2:

[0040] Table 1 Water sample test data in sewage treatment

[0041] <![CDATA[F - (mg / L)]]> <![CDATA[B4O7 2- (mg / L)]]> <![CDATA[Na + (mg / L)]]> <![CDATA[SO4 2- (mg / L)]]> Salt content (mg / L) Water sample before treatment 49600 95970 26700 70750 198000 Water sample after defluorination treatment 8670 90080 23720 64830 167000 Water sample after primary crystallization 8550 26820 17030 59520 146000 Water sample after secondary crystallization 8580 19190 10720 16420 80000

[0042] As can be seen from Table 1, the fluoride ion dropped from 49600 mg / L before treatment to 8670 mg / L, with a decrease rate of 82.5%; B4O7 2- After one crystallization, the concentration of SO4 decreased from 90080mg / L to 26820mg / L, with a decrease rate of 70.2%; 2-After secondary crystallization, the concentration of sulfur, boron, fluorine and other pollutants in the sewage sample treated by the present invention was greatly reduced, which reduced the difficulty and cost of subsequent sewage treatment.

[0043] Table 2 Detection data of wastewater treatment products white mud (calcium fluoride) and crystallized products

[0044] product <![CDATA[Na2O(wt%)]]> CaO (wt%) S (wt%) <![CDATA[B2O3(wt%)]]> F (wt%) White clay 2.58 58.50 1.50 1.24 34.16 Primary crystallization 20.8 0.31 0.93 47.2 0.12 Secondary crystallization 43.63 0.19 31.06 0.28 Not detected

[0045] As can be seen from Table 2, the main component of the white mud obtained by the present invention is calcium fluoride, and the content of other impurities is relatively low; after primary crystallization and drying, it is mainly sodium borate, and the rest is crystal water, and the impurity content is low; after secondary crystallization and drying, the main component is sodium sulfate, and the impurity content is low. The above three substances can be reused as raw materials in the production process.

[0046] Example 2

[0047] (1) The wastewater from the waste gas absorbed by the spray tower enters the circulating water pool 7, and the wastewater in the circulating water pool 7 is introduced into the spray tower for recycling as an adsorbent to supplement alkali in the wastewater in the circulating water pool 7;

[0048] (2) The sewage in the circulating water pool 7 is introduced into the stirring reaction tank 43, and calcium carbonate is added into the water body. The added mass is confirmed according to the fluorine content in the water, and the pH value of the reaction slurry is controlled to be between 6 and 7. The reaction is stirred in the stirring reaction tank 43 for 60 minutes, and the stirring reaction temperature is 25° C. After the reaction is completed, it is pumped into the precipitation tank 3 for precipitation. After the precipitation is complete, the upper clear liquid in the precipitation tank 3 is introduced into the water storage tank 1 for temporary storage. The precipitation at the bottom of the precipitation tank 3 is pumped into the mud press 39 by a wear-resistant mortar pump for mud pressing treatment to obtain white mud (calcium fluoride);

[0049] (3) introducing the sewage in the water storage tank 1 into the first crystallizer 35, opening the first heat exchanger 34 to control the sewage temperature, controlling the sewage temperature to 10° C., allowing sodium borate to crystallize, pumping the mixed solution in the first crystallizer 35 into the first thickener 25 for concentration, and the concentrated slurry enters the first centrifuge 26. The sodium borate crystals separated by the first centrifuge 26 enter the first storage tank 28 for storage, and the supernatant liquid in the first thickener 25 and the sewage separated by the first centrifuge 26 enter the second crystallizer 14;

[0050] (4) The second heat exchanger 20 is turned on to control the sewage temperature, and the sewage temperature is controlled to be 1° C. to allow sodium sulfate to crystallize and precipitate. The mixed liquid in the second crystallizer 14 is pumped into the second thickener 12 for concentration, and the concentrated slurry enters the second centrifuge 17. The sodium sulfate crystals separated by the second centrifuge 17 enter the second storage tank 18 for storage, and the supernatant liquid in the second thickener 12 and the sewage separated by the second centrifuge 17 enter the circulating water tank 7 for recycling.

[0051] In step (1), the alkali is a 33% sodium hydroxide solution, and the amount of alkali supplement is 2-3m 3 / d.

[0052] Example 3

[0053] (1) The wastewater from the waste gas absorbed by the spray tower enters the circulating water pool 7, and the wastewater in the circulating water pool 7 is introduced into the spray tower for recycling as an adsorbent to supplement alkali in the wastewater in the circulating water pool 7;

[0054] (2) The sewage in the circulating water pool 7 is introduced into the stirring reaction tank 43, and calcium carbonate is added into the water body. The added mass is confirmed according to the fluorine content in the water, and the pH value of the reaction slurry is controlled to be between 6 and 7. The reaction is stirred in the stirring reaction tank 43 for 25 minutes, and the stirring reaction temperature is 45° C. After the reaction is completed, it is pumped into the precipitation tank 3 for precipitation. After the precipitation is complete, the upper clear liquid in the precipitation tank 3 is introduced into the water storage tank 1 for temporary storage. The precipitation at the bottom of the precipitation tank 3 is pumped into the mud press 39 by a wear-resistant mortar pump for mud pressing treatment to obtain white mud (calcium fluoride);

[0055] (3) introducing the sewage in the water storage tank 1 into the first crystallizer 35, opening the first heat exchanger 34 to control the sewage temperature, controlling the sewage temperature to 10° C., allowing sodium borate to crystallize, pumping the mixed solution in the first crystallizer 35 into the first thickener 25 for concentration, and the concentrated slurry enters the first centrifuge 26. The sodium borate crystals separated by the first centrifuge 26 enter the first storage tank 28 for storage, and the supernatant liquid in the first thickener 25 and the sewage separated by the first centrifuge 26 enter the second crystallizer 14;

[0056] (4) The second heat exchanger 20 is turned on to control the sewage temperature, and the sewage temperature is controlled to be 7° C. to allow sodium sulfate to crystallize and precipitate. The mixed liquid in the second crystallizer 14 is pumped into the second thickener 12 for concentration, and the concentrated slurry enters the second centrifuge 17. The sodium sulfate crystals separated by the second centrifuge 17 enter the second storage tank 18 for storage, and the supernatant liquid in the second thickener 12 and the sewage separated by the second centrifuge 17 enter the circulating water tank 7 for recycling.

[0057] In step (1), the alkali is a 33% sodium hydroxide solution, and the amount of alkali supplement is 2-3m 3 / d.

Claims

1. A glass fiber production waste gas treatment device, comprising a spray tower, the spray tower is connected to a circulating water pool (7) for storing adsorbent, characterized in that: The invention also comprises a stirring reaction tank (43), a precipitation tank (3), a mud press (39), a water storage tank (1), a first crystallization tank (35), a first heat exchanger (34), a second crystallization tank (14), and a second heat exchanger (20); a first circulating water pipe (32) and a second circulating water pipe (21) are respectively arranged between the upper part and the bottom end of the first crystallization tank (35) and the second crystallization tank (14); and a first heat exchanger (32) and a second circulating water pipe (21) are respectively arranged on the first circulating water pipe (32) and the second circulating water pipe (21). 4), a second heat exchanger (20), the bottom of the first crystallizer (35) is connected to the first storage tank (28) through a first discharge pipe (29), the first discharge pipe (29) is provided with a first centrifuge (26), the first centrifuge (26) is also connected to the second circulating water pipe (21) above the second heat exchanger (20) through a sixth pipeline (23), the bottom of the second crystallizer (14) is connected to the second storage tank (18) through a second discharge pipe (19), the second discharge pipe (19) is provided with a first centrifuge (26), the first centrifuge (26) is also connected to the second circulating water pipe (21) above the second heat exchanger (20) through a sixth pipeline (23), the bottom of the second crystallizer (14) is connected to the second storage tank (18) through a second discharge pipe (19), A second centrifuge (17) is provided, and the second centrifuge (17) is also connected to a circulating water tank (7) through an eighth pipeline (8); the circulating water tank (7) is connected to a stirring reaction tank (43) through a first pipeline (44), the stirring reaction tank (43) is connected to a sedimentation tank (3) through a second pipeline (4), the sedimentation tank (3) is connected to a water storage tank (1) through a third pipeline (2), the bottom of the sedimentation tank (3) is connected to a mud press (39) through an eleventh pipeline (41), and the water storage tank (1) The first crystallizer (35) is connected to the first thickener (25) via the fifth pipeline (27), the first thickener (25) is connected to the sixth pipeline (23) via the ninth pipeline (24), the second crystallizer (14) is connected to the second thickener (12) via the seventh pipeline (13), and the second thickener (12) is connected to the eighth pipeline (8) via the tenth pipeline (11); Wherein: the second pipeline (4) is provided with a lifting pump (42), the eleventh pipeline (41) is provided with a first screw pump (40), the fourth pipeline (36) is provided with a first feed pump (33), the first circulating water pipe (32) is provided with a first axial flow circulating pump (31), the fifth pipeline (27) is provided with a first crystal material discharge pump (30), the sixth pipeline (23) is provided with a second feed pump (22), the second circulating water pipe (21) is provided with a second axial flow circulating pump (16), the seventh pipeline (13) is provided with a second crystal material discharge pump (15), the eighth pipeline (8) is provided with a third feed pump (9), and the first pipeline (44) is provided with a circulating water pump (10).

2. The glass fiber production waste gas treatment device according to claim 1, characterized in that: A silo (5) is provided beside the stirring reaction tank (43), and an electronic scale (6) is provided directly below the silo (5).

3. The glass fiber production waste gas treatment device according to claim 1, characterized in that: The bottom of the water storage tank (1) is connected to the mud press (39) via a twelfth pipeline (37), and a second screw pump (38) is provided on the twelfth pipeline (37).

4. A process for treating waste gas from glass fiber production according to any one of claims 1 to 3, characterized in that: The steps include: (1) The wastewater from the waste gas is absorbed by the spray tower and enters the circulating water pool (7). The wastewater in the circulating water pool (7) is introduced into the spray tower and recycled as an adsorbent to replenish alkali in the wastewater in the circulating water pool (7); (2) introducing the sewage in the circulating water pool (7) into a stirred reaction tank (43), adding a defluorinating agent, stirring and defluorinating, and introducing the sewage into a sedimentation tank (3) after defluorinating. After sedimentation, introducing the upper clear liquid in the sedimentation tank (3) into a water storage tank (1) for temporary storage. The sediment in the lower part of the sedimentation tank (3) is pumped into a mud press (39) for mud pressing treatment; (3) introducing the sewage in the water storage tank (1) into the first crystallization tank (35), opening the first heat exchanger (34) to control the sewage temperature, so that sodium borate crystals are precipitated, pumping the mixed liquid in the first crystallization tank (35) into the first thickener (25) for concentration, the concentrated slurry enters the first centrifuge (26), the sodium borate crystals separated by the first centrifuge (26) enter the first storage tank (28) for storage, and the supernatant liquid in the first thickener (25) and the sewage separated by the first centrifuge (26) enter the second crystallization tank (14); (4) The second heat exchanger (20) is turned on to control the temperature of the sewage so that sodium sulfate crystals are precipitated, and the mixed liquid in the second crystallization tank (14) is pumped into the second thickener (12) for concentration, and the concentrated slurry enters the second centrifuge (17). The sodium sulfate crystals separated by the second centrifuge (17) are stored in the second storage tank (18), and the supernatant liquid in the second thickener (12) and the sewage separated by the second centrifuge (17) are recycled into the circulating water tank (7).

5. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: In step (1), the alkali solution is one or more of sodium hydroxide solution, sodium carbonate solution and sodium bicarbonate solution.

6. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: In step (2), the defluorinating agent is one or more of calcium hydroxide, calcium carbonate or calcium oxide.

7. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: The defluorination process in step (2) is as follows: adjusting pH to 6-7, reaction temperature to 25-45° C., and reaction time to 10-60 min.

8. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: In step (3), the sewage temperature is controlled to be 10-18°C.

9. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: In step (4), the sewage temperature is controlled to be 1-7°C.

10. The process for treating waste gas from glass fiber production according to claim 4, characterized in that: The sediment at the bottom of the water storage tank (1) is pumped into a mud compactor (39) for mud compaction treatment.

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