Sewage treatment agent and preparation method thereof

Abstract

The invention discloses a sewage treatment agent and a preparation method thereof, and belongs to the technical field of sewage silicon removal, and the sewage treatment agent comprises the following components: 50-60 parts of poly aluminum ferric chloride, 15-20 parts of sodium metaaluminate, 12-20 parts of acid pickling activated fly ash, 5-10 parts of magnesium hydroxide and 1-3 parts of modified anionic polyacrylamide. Mixing and drying to obtain the sewage treatment agent. Through the synergistic effect of sodium lignin sulfonate and acid pickling activated fly ash, the selective adsorption capacity and reaction activity of the agent to silicon are remarkably improved, meanwhile, agglomeration and sedimentation of sludge particles are promoted, and the total generation amount of sludge in the sewage treatment process is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage desilication, in particular to a sewage treatment agent and a preparation method thereof. BACKGROUND

[0002] In the process of industrial production, the discharge of sewage containing silicon exists widely in many fields such as semiconductor manufacturing, photovoltaic industry, metallurgy, chemical industry, etc. The silicon in such sewage exists in the form of colloidal silicon, dissolved silicon, etc. If it is discharged directly without effective treatment, it will not only cause eutrophication of water body and affect the ecological balance of aquatic life, but also form insoluble silicate scale in the subsequent water treatment system, block the pipeline and equipment, and seriously affect the production operation efficiency. Therefore, the standard treatment of sewage containing silicon has become an important issue in the field of industrial wastewater treatment.

[0003] At present, the desilication technologies developed and applied in the industry mainly include chemical precipitation method, adsorption method, membrane separation method, etc. These technologies can reduce the silicon content in the sewage to a certain extent and meet the basic discharge standard, but they all have the problem of excessive sludge output. Taking the chemical precipitation method as an example, by adding chemical agents such as calcium salt and aluminum salt, the silicon components in the sewage react to form insoluble precipitates, and then the desilication is realized through solid-liquid separation.

[0004] The collection, transportation, dewatering, solidification / stabilization and final disposal such as landfill and incineration of sludge all require a large amount of manpower, material resources and financial resources, which directly increases the overall cost of sewage treatment. In order to pursue higher desilication efficiency, enterprises often need to further increase the dosage of chemical agents, which will directly promote the growth of sludge generation and further exacerbate the problem.

[0005] Based on this, the present application designs a sewage treatment agent and a preparation method thereof to solve the above problems. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the present application provides a preparation method of a sewage treatment agent, comprising the following steps: S1: mixing fly ash and hydrochloric acid, stirring at room temperature, filtering and washing, and drying and crushing to obtain acid-washed activated fly ash; S2: drying and crushing polyaluminum ferric chloride, sodium metaaluminate and magnesium hydroxide respectively; S3: weighing 45-75 parts of anionic polyacrylamide, 10-20 parts of dimethyldiallylammonium chloride, 5-10 parts of sodium lignosulfonate and 1-3 parts of potassium dihydrogen phosphate by weight; The anionic polyacrylamide is added to deionized water to obtain an anionic polyacrylamide aqueous solution; the sodium lignosulfonate and the potassium dihydrogen phosphate are added to deionized water and stirred to obtain a composite additive; The anionic polyacrylamide aqueous solution is heated to 50-60℃, dimethyldiallylammonium chloride is added dropwise, stirred for 40-60min, the composite additive is added, stirred for 60-90min, the pH is adjusted to 7.5-8.5, cooled to 25-30℃, stirred for 10-15min, to obtain a modified reaction solution, concentrated, spray dried to obtain modified anionic polyacrylamide; S4: 50-60 parts by weight of polyaluminum ferric chloride, 15-20 parts by weight of sodium metaaluminate, 12-20 parts by weight of pickling activated fly ash, 5-10 parts by weight of magnesium hydroxide, 1-3 parts by weight of modified anionic polyacrylamide are weighed; S5: Deionized water is added to the stirred tank, heated to 40-50℃ and stirred, sodium metaaluminate is added, stirred for 20-30min, polyaluminum ferric chloride and magnesium hydroxide are added in turn, with an interval of 10-15min, stirred for 40-60min, pickling activated fly ash is added, continue to stir for 30-40min, reduce the stirring speed, add modified anionic polyacrylamide in 2-3 times, stir for 15-20min, to obtain a mixed slurry; S6: The mixed slurry is pumped into a pressure type spray drying tower, dried and sieved to obtain a sewage treatment agent.

[0007] Further, S1 is specifically: the fly ash is mixed with 5-8% industrial hydrochloric acid by solid-liquid ratio 1:10-12, stirred at room temperature for 60-90min, after plate and frame pressure filtration, washed with industrial water until the pH is 6-7, hot air dried at 105-110℃ for 4-6h, crushed to 200 mesh, to obtain pickling activated fly ash.

[0008] Further, S2 is specifically: polyaluminum ferric chloride, sodium metaaluminate and magnesium hydroxide are respectively dried at 100-120℃ hot air for 2-3h, and respectively crushed to 200 mesh or less.

[0009] Further, S3 is specifically: 45-75 parts by weight of anionic polyacrylamide, 10-20 parts by weight of dimethyldiallylammonium chloride, 5-10 parts by weight of sodium lignosulfonate, and 1-3 parts by weight of potassium dihydrogen phosphate are weighed; The anionic polyacrylamide is added to 640-840 parts of deionized water, stirred at 100-200r / min for 30-60min at 25-35℃, to prepare an anionic polyacrylamide aqueous solution; The sodium lignosulfonate and potassium dihydrogen phosphate are added to 160-360 parts of deionized water, stirred at 40-50℃ for 20-30min, to obtain a composite additive; The anionic polyacrylamide aqueous solution is warmed to 50-60 DEG C, dimethyl diallyl ammonium chloride is added dropwise at 1-2 mL / s, stirring is carried out at 200-300 r / min for 40-60 min, the composite additive is added, the stirring rate is reduced to 150-250 r / min, stirring is carried out for 60-90 min, the pH is adjusted to 7.5-8.5 by sodium hydroxide solution, the temperature is reduced to 25-30 DEG C at 1-2 DEG C / min, and stirring is carried out for 10-15 min to obtain a modified reaction solution; The modified reaction solution is placed in a vacuum concentration tank, concentrated at 50-60 DEG C under a vacuum degree of 0.04-0.07 MPa for 30-50 min to obtain a concentrated solution with an original volume of 10-15%, the concentrated solution is pumped into a pressure type spray drying tower, the inlet temperature is controlled at 180-200 DEG C, the outlet temperature is controlled at 80-90 DEG C, and the atomization pressure is controlled at 0.2-0.4 MPa to obtain modified anionic polyacrylamide.

[0010] Further, S5 is specifically: 3-7 parts of deionized water are added to an industrial stirred tank, warmed to 40-50 DEG C at 2-4 DEG C / min, and kept at 40-50 DEG C for 20-30 min, and stirring is carried out at 300-500 r / min, sodium metaaluminate is added at one time, stirring is carried out for 20-30 min, polyaluminum ferric chloride and magnesium hydroxide are added in sequence, and stirring is carried out for 40-60 min with an interval of 10-15 min, acid-washed activated fly ash is added, and stirring is continued for 30-40 min, the stirring rate is reduced to 200-300 r / min, modified anionic polyacrylamide is added in 2-3 portions with an interval of 5-8 min, and stirring is carried out for 15-20 min to obtain a mixed slurry.

[0011] Further, S6 is specifically: the mixed slurry is pumped into a pressure type spray drying tower, the inlet temperature is controlled at 200-220 DEG C, the outlet temperature is controlled at 90-100 DEG C, the atomization pressure is controlled at 0.3-0.5 MPa, and drying and sieving are carried out to obtain a sewage treatment agent.

[0012] A sewage treatment agent prepared according to the preparation method.

[0013] Compared with the prior art, the sewage treatment agent has the following beneficial effects: 1、The sodium lignosulfonate and the acid-washed activated fly ash are synergistically combined, the selectivity of the agent to silicon is significantly improved, the reaction activity is improved, and the generation of sludge in the sewage treatment process is reduced, so that the manpower, material resources and financial resources required for sludge disposal are reduced, the cost structure of the sewage treatment is fundamentally optimized, and the economic efficiency and feasibility of industrial wastewater treatment are improved.

[0014] 2、The present application can greatly reduce sludge, ensure stable and excellent silicon removal effect, efficiently remove silicon components in the form of colloidal silicon and dissolved silicon in the sewage, ensure that the treated sewage meets the relevant discharge standards, is easy to produce and apply on a large scale, and can be widely applied to the treatment of silicon-containing sewage in the fields of semiconductor manufacturing, photovoltaic industry, metallurgy, chemical industry and the like. DETAILED DESCRIPTION

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the technical solutions in the embodiments of the present application for a clear and complete description. Obviously, the described embodiments are some embodiments but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0016] Embodiment 1: The present embodiment discloses a preparation method of a sewage treatment agent, comprising the following steps: S1: mixing fly ash and industrial hydrochloric acid with a mass fraction of 5% according to a solid-liquid ratio of 1:10, stirring at room temperature for 60 min, washing with industrial water to pH 6-7 after plate and frame pressure filtration, hot air drying at 105℃ for 4 h, and crushing to 200 meshes to obtain acid-washed activated fly ash; S2: respectively drying polyaluminum ferric chloride (Zhengzhou Anbo Environmental Protection Technology Co., Ltd., 40-60 meshes), sodium metaaluminate, and magnesium hydroxide at 100℃ for 2 h, and respectively crushing to 200 meshes or less; S3: weighing 45 parts of anionic polyacrylamide (Henna Zesheng Water Purification Material Co., Ltd.), 10 parts of dimethyldiallylammonium chloride, 5 parts of sodium lignosulfonate, and 1 part of potassium dihydrogen phosphate; adding the anionic polyacrylamide into 640 parts of deionized water, stirring at 100 r / min at 25℃ for 30 min to prepare an anionic polyacrylamide aqueous solution; adding the sodium lignosulfonate and the potassium dihydrogen phosphate into 160 parts of deionized water, stirring at 40℃ for 20 min to obtain a composite additive; warming the anionic polyacrylamide aqueous solution to 50℃, adding the dimethyldiallylammonium chloride (Shandong Luyu Chemical Group Co., Ltd.) dropwise at 1 mL / s, stirring at 200 r / min for 40 min, adding the composite additive, reducing the stirring speed to 150 r / min, stirring for 60 min, adjusting the pH to 7.5-8.5 by sodium hydroxide solution, reducing the temperature to 25℃ at 1℃ / min, and stirring for 10 min to obtain a modified reaction solution; The modified reaction solution is placed in a vacuum concentration tank, concentrated at 50℃ under a vacuum degree of 0.04-0.07 MPa for 30 min, to obtain a concentrated solution with an original volume of 10%, and the concentrated solution is pumped into a pressure type spray drying tower, with the inlet temperature controlled at 180-200℃, the outlet temperature controlled at 80-90℃, and the atomization pressure controlled at 0.2 MPa, to obtain the modified anionic polyacrylamide; S4: 50 parts of polyaluminum ferric chloride, 15 parts of sodium metaaluminate, 12 parts of acid-washing activated fly ash, 5 parts of magnesium hydroxide, and 1 part of modified anionic polyacrylamide are weighed by weight parts; S5: 3 parts of deionized water are added to an industrial stirred tank, heated to 40℃ at a rate of 2℃ / min, and kept at 40℃ for 20 min, stirred at 300 r / min, sodium metaaluminate is added at one time, stirred for 20 min, polyaluminum ferric chloride and magnesium hydroxide are added in turn, with an interval of 10 min, stirred for 40 min, acid-washing activated fly ash is added, and stirred for another 30 min, the stirring speed is reduced to 200 r / min, modified anionic polyacrylamide is added in two portions with an interval of 5 min, and stirred for 15 min, to obtain a mixed slurry; S6: The mixed slurry is pumped into a pressure type spray drying tower, with the inlet temperature controlled at 200-220℃, the outlet temperature controlled at 90-100℃, and the atomization pressure controlled at 0.3 MPa, dried, sieved (100 mesh vibration sieve screening), to obtain the sewage treatment agent.

[0017] Embodiment 2: The embodiment discloses a preparation method of a sewage treatment agent, comprising the following steps: S1: The fly ash is mixed with industrial hydrochloric acid with a mass fraction of 8% according to a solid-liquid ratio of 1:12, stirred at room temperature for 90 min, washed with industrial water until the pH is 6-7 after plate and frame pressure filtration, dried by hot air at 110℃ for 6 h, and crushed to 200 mesh to obtain acid-washing activated fly ash; S2: The polyaluminum ferric chloride (Zhengzhou Anbo Environmental Protection Technology Co., Ltd., 40-60 mesh), sodium metaaluminate, and magnesium hydroxide are dried by hot air at 120℃ for 3 h respectively, and crushed to 200 mesh or less respectively; S3: 75 parts of anionic polyacrylamide (Henna Zesheng Water Purification Material Co., Ltd.), 20 parts of dimethyldiallylammonium chloride, 10 parts of sodium lignosulfonate, and 3 parts of potassium dihydrogen phosphate are weighed by weight parts; The anionic polyacrylamide is added to 840 parts of deionized water, stirred at 200 r / min at 35℃ for 60 min, to prepare an anionic polyacrylamide aqueous solution; The sodium lignosulfonate and potassium dihydrogen phosphate are added to 360 parts of deionized water, stirred at 50℃ for 30 min, to obtain a composite additive; The anionic polyacrylamide aqueous solution is warmed to 60℃, dimethyldiallylammonium chloride (Shandong Luyu Chemical Group Co., Ltd.) is added dropwise at 2 mL / s, stirring is carried out at 300 r / min for 60 min, the composite additive is added, the stirring rate is reduced to 250 r / min, stirring is carried out for 90 min, the pH is adjusted to 7.5-8.5 by means of a sodium hydroxide solution, the temperature is reduced to 30℃ at 2℃ / min, stirring is carried out for 15 min, and a modified reaction solution is obtained; The modified reaction solution is placed in a vacuum concentration tank, concentrated at 60℃ under a vacuum degree of 0.04-0.07 MPa for 50 min, a concentrated solution with an original volume of 15% is obtained, the concentrated solution is pumped into a pressure type spray drying tower, the inlet temperature is controlled to be 180-200℃, the outlet temperature is controlled to be 80-90℃, and the atomization pressure is controlled to be 0.4 MPa, and modified anionic polyacrylamide is obtained; S4: 60 parts of polyaluminum ferric chloride, 20 parts of sodium metaaluminate, 20 parts of acid-washing activated fly ash, 10 parts of magnesium hydroxide and 3 parts of modified anionic polyacrylamide are weighed according to weight parts; S5: 7 parts of deionized water are added to an industrial stirring kettle, the temperature is increased to 50℃ at 4℃ / min, and the temperature is kept for 30 min, 500 r / min stirring is carried out, sodium metaaluminate is added at one time, stirring is carried out for 30 min, polyaluminum ferric chloride and magnesium hydroxide are added in sequence, the interval is 15 min, stirring is carried out for 60 min, acid-washing activated fly ash is added, and stirring is continuously carried out for 40 min, the stirring rate is reduced to 300 r / min, modified anionic polyacrylamide is added in three times, the interval is 8 min, and stirring is carried out for 20 min, and a mixed slurry is obtained; S6: the mixed slurry is pumped into a pressure type spray drying tower, the inlet temperature is controlled to be 200-220℃, the outlet temperature is controlled to be 90-100℃, the atomization pressure is controlled to be 0.5 MPa, and the sewage treatment agent is obtained by drying and sieving (100 mesh vibration sieve screening).

[0018] Embodiment 3: The embodiment discloses a preparation method of a sewage treatment agent, and comprises the following steps: S1: fly ash is mixed with industrial hydrochloric acid with a mass fraction of 5-8% according to a solid-liquid ratio of 1:11, stirring is carried out at room temperature for 85 min, plate and frame pressure filtration is carried out, and then washing is carried out with industrial water until the pH is 6-7, hot air drying is carried out at 107℃ for 5.5 h, crushing is carried out to 200 mesh, and acid-washing activated fly ash is obtained; S2: polyaluminum ferric chloride (Zhengzhou Anbo Environmental Protection Technology Co., Ltd., 40-60 mesh), sodium metaaluminate and magnesium hydroxide are respectively dried by hot air at 113℃ for 2 h, and are respectively crushed to below 200 mesh; S3: 72 parts of anionic polyacrylamide (Henan Zesheng Water Purification Material Co., Ltd.), 11 parts of dimethyldiallylammonium chloride, 6 parts of sodium lignosulfonate and 1.4 parts of potassium dihydrogen phosphate are weighed according to weight parts; Anionic polyacrylamide was added into 720 parts of deionized water, stirred at 130 r / min for 42 min at 32℃ to prepare an anionic polyacrylamide aqueous solution; Sodium lignosulfonate and potassium dihydrogen phosphate were added into 240 parts of deionized water, stirred at 44℃ for 25 min to obtain a composite additive; The anionic polyacrylamide aqueous solution was heated to 51℃, and dimethyldiallylammonium chloride (Shandong Luyu Chemical Group Co., Ltd.) was added dropwise at a rate of 1.2 mL / s, stirred at 220 r / min for 47 min, and then the composite additive was added, the stirring rate was reduced to 180 r / min, and stirred for 73 min, and then the pH was adjusted to 7.5-8.5 by sodium hydroxide solution, and then the temperature was reduced to 29℃ at a rate of 2℃ / min, and stirred for 14 min to obtain a modified reaction solution; The modified reaction solution was placed in a vacuum concentration tank, concentrated at a vacuum degree of 0.04-0.07 MPa and 55℃ for 37 min to obtain a concentrated solution with an original volume of 12%, and then the concentrated solution was pumped into a pressure type spray drying tower, the inlet temperature was controlled at 180-200℃, the outlet temperature was controlled at 80-90℃, and the atomization pressure was controlled at 0.3 MPa to obtain modified anionic polyacrylamide; S4: 51 parts of polyaluminum ferric chloride, 17 parts of sodium metaaluminate, 18 parts of acid-washing activated fly ash, 6 parts of magnesium hydroxide, and 1.7 parts of modified anionic polyacrylamide were weighed according to parts by weight; S5: 4 parts of deionized water were added into an industrial stirred tank, heated to 42℃ at a rate of 3℃ / min, and kept at 42℃ for 22 min, stirred at 350 r / min, and then sodium metaaluminate was added at one time, stirred for 27 min, and then polyaluminum ferric chloride and magnesium hydroxide were added in sequence, with an interval of 12 min, and stirred for 49 min, then the acid-washing activated fly ash was added, and the stirring was continued for 36 min, then the stirring rate was reduced to 270 r / min, and the modified anionic polyacrylamide was added in three portions with an interval of 6 min, and stirred for 17 min to obtain a mixed slurry; S6: The mixed slurry was pumped into a pressure type spray drying tower, the inlet temperature was controlled at 200-220℃, the outlet temperature was controlled at 90-100℃, and the atomization pressure was controlled at 0.5 MPa, and then the sewage treatment agent was obtained by drying and sieving (100 mesh vibration sieve screening).

[0019] Example 4: The present embodiment discloses a preparation method of a sewage treatment agent, which comprises the following steps: S1: The fly ash was mixed with industrial hydrochloric acid with a mass fraction of 6% according to a solid-liquid ratio of 1:10.5, stirred at room temperature for 65 min, washed with industrial water to pH 6-7 after plate and frame pressure filtration, dried with hot air at 106℃ for 4 h, crushed to 200 mesh, and then acid-washing activated fly ash was obtained; S2:Polyaluminum ferric chloride (Zhengzhou Anbo Environmental Protection Technology Co., Ltd., 40-60 mesh), sodium metaaluminate, magnesium hydroxide were dried at 113℃ for 2h by hot air, and were crushed to 200 mesh or less, respectively; S3:64 parts of anionic polyacrylamide (Henna Zesheng Water Purification Material Co., Ltd.), 12 parts of dimethyl diallyl ammonium chloride, 9 parts of sodium lignosulfonate, 1 part of potassium dihydrogen phosphate were weighed by weight parts; Anionic polyacrylamide was added to 830 parts of deionized water, stirred at 110 r / min at 34℃ for 48 min to prepare an anionic polyacrylamide aqueous solution; Sodium lignosulfonate and potassium dihydrogen phosphate were added to 270 parts of deionized water, stirred at 46℃ for 28 min to obtain a composite additive; The anionic polyacrylamide aqueous solution was heated to 57℃, and dimethyl diallyl ammonium chloride (Shandong Luyu Chemical Group Co., Ltd.) was added at a rate of 1.6 mL / s, stirred at 270 r / min for 43 min, and the composite additive was added. The stirring rate was reduced to 200 r / min, and stirred for 81 min. The pH was adjusted to 7.5-8.5 by sodium hydroxide solution, and the temperature was reduced to 28℃ at a rate of 2℃ / min. Stirring for 13 min, a modified reaction solution was obtained; The modified reaction solution was placed in a vacuum concentration tank, and concentrated at 57℃ under a vacuum of 0.04-0.07 MPa for 40 min to obtain a concentrated solution with an original volume of 12%. The concentrated solution was pumped into a pressure type spray drying tower, and the inlet temperature was controlled at 180-200℃, the outlet temperature was controlled at 80-90℃, and the atomization pressure was controlled at 0.4 MPa. Modified anionic polyacrylamide was obtained. S4:55 parts of polyaluminum ferric chloride, 16 parts of sodium metaaluminate, 19 parts of acid-washing activated fly ash, 8 parts of magnesium hydroxide, and 1.4 parts of modified anionic polyacrylamide were weighed by weight parts; S5:6 parts of deionized water were added to an industrial stirred tank, heated to 42℃ at a rate of 3℃ / min, and kept at 42℃ for 22 min. Stir at 370 r / min, add sodium metaaluminate at once, stir for 25 min, add polyaluminum ferric chloride and magnesium hydroxide in turn, interval 14 min, stir for 58 min, add acid-washing activated fly ash, continue to stir for 37 min, reduce the stirring speed to 260 r / min, add modified anionic polyacrylamide in 3 times, interval 5 min, stir for 19 min, and obtain a mixed slurry. S6: The mixed slurry was pumped into a pressure type spray drying tower, and the inlet temperature was controlled at 200-220℃, the outlet temperature was controlled at 90-100℃, and the atomization pressure was controlled at 0.5 MPa. The sewage treatment agent was obtained by drying and sieving (100 mesh vibration sieve screening).

[0020] Comparative Example 1: The difference between this comparative example and Example 3 is that in S3, the composite additive does not contain sodium lignosulfonate.

[0021] Comparative Example 2: The difference between this comparative example and Example 3 is that S1 is not performed, i.e. the fly ash is not activated by acid washing.

[0022] Comparative Example 3: The difference between this comparative example and Example 3 is that S1 is not performed, i.e. the fly ash is not activated by acid washing; in S3, the composite additive does not contain sodium lignosulfonate.

[0023] Control Example: The silicon removal agent is prepared according to Example 1 of Chinese Patent CN112062249B.

[0024] Preparation Example: The sewage containing silicon first enters the conditioning tank, and the suspended solid impurities with particle size ≥20-50 mesh are removed by grating filtration. The influent flow rate is controlled at 10-30 m 3 / h, industrial-grade sodium hydroxide solution (concentration 20%) is added to the conditioning tank, the reaction pH value is controlled at 8.0-9.5 by an online pH monitor, the stirring rate is 200 r / min, and the stirring time is 20 minutes. The silicon content of the sewage after the above pretreatment is controlled at 50-1000 mg / L, and the temperature is maintained at 30±5℃; According to the volume of the sewage, the sewage treatment agent prepared in the examples, comparative examples and preparation example (silicon agent ratio 1:5) of the present application is added to the pretreated sewage at a silicon agent ratio of 1:1.5, and is continuously added to the mixing tank by a metering pump. The mixing tank is stirred at a stirring rate of 500 r / min for 10 min to form a mixed solution. The mixed solution is transferred to the reaction tank, and the stirring rate is adjusted to 150 r / min. The reaction is carried out for 20 min to form alum flowers. The reacted mixed solution enters the sedimentation tank, and the hydraulic retention time is controlled at 60 min. The alum flowers naturally sink to the bottom of the tank to form a sludge layer. The supernatant of the sedimentation tank is discharged through an overflow weir, and the silicon content is detected before discharge. The sludge at the bottom of the sedimentation tank is collected by a mud scraper into a sludge hopper. The sludge in the sludge hopper is transported to the thickening tank by a sludge pump. The thickening time is 12-24 h. The thickened sludge enters the plate-and-frame filter press, and the filter pressing pressure is controlled at 1.2 MPa. The filter pressing time is 4 h to form a mud cake. The mud cake meets the hazardous waste identification standard, and is disposed of by a professional environmental protection unit. The mud cake meets the general solid waste standard, and can be used for brick making, roadbed backfilling and other resource utilization.

[0025] Experimental Example 1: The silicon concentration (mg / L) before and after treatment is detected according to GB / T 9742-2008 “Chemical Reagents General Determination Method for Silicates”, and the silicon removal rate (%) is calculated.

[0026] Experimental Example 2: The sludge yield is calculated according to the sludge amount of the preparation example.

[0027]

[0028] Actual sludge dry mass = cake mass (kg); Total silicon removed in wastewater = (initial silicon concentration - post-treatment silicon concentration) x treated wastewater volume x wastewater density (approximately 1 kg / L).

[0029] The results are shown in the following table:

[0030] As shown in the above table, compared with the prior art, the sludge output of the present application is greatly reduced; in terms of silicon removal effect, all examples maintain stable and excellent performance, indicating that the present application greatly reduces the sludge while not sacrificing the silicon removal effect; The comparative examples that lack sodium lignosulfonate or do not perform acid washing activation on fly ash all have more sludge output than the examples, and the comparative example that lacks both has a more obvious increase in sludge output; this indicates that the two can improve the selective adsorption and reaction activity of silicon, promote sludge agglomeration and sedimentation, and thus reduce the total mass of sludge.

[0031] The above examples are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a wastewater treatment agent, characterized in that, Includes the following steps: S1: Mix fly ash with hydrochloric acid, stir at room temperature, filter, wash, dry and pulverize to obtain acid-washed activated fly ash; S2: Dry and pulverize polyaluminum ferric chloride, sodium aluminate, and magnesium hydroxide separately; S3: Weigh out 45-75 parts by weight of anionic polyacrylamide, 10-20 parts by weight of dimethyl diallyl ammonium chloride, 5-10 parts by weight of sodium lignosulfonate, and 1-3 parts by weight of potassium dihydrogen phosphate. Anionic polyacrylamide was added to deionized water and stirred to obtain an aqueous solution of anionic polyacrylamide; sodium lignosulfonate and potassium dihydrogen phosphate were added to deionized water and stirred to obtain a composite additive. Heating anionic polyacrylamide aqueous solution to 50-60℃, adding dimethyl diallyl ammonium chloride dropwise, stirring for 40-60 min, adding composite additives, stirring for 60-90 min, adjusting pH to 7.5-8.5, cooling to 25-30℃, stirring for 10-15 min, obtaining modified reaction solution, concentrating and spray drying to obtain modified anionic polyacrylamide; S4: Weigh out 50-60 parts by weight of polyaluminum ferric chloride, 15-20 parts by weight of sodium aluminate, 12-20 parts by weight of acid-washed and activated fly ash, 5-10 parts by weight of magnesium hydroxide, and 1-3 parts by weight of modified anionic polyacrylamide. S5: Add deionized water to the mixing tank, heat to 40-50℃ and stir, add sodium aluminate, stir for 20-30 min, add polyaluminum ferric chloride and magnesium hydroxide in sequence, with an interval of 10-15 min, stir for 40-60 min, add acid-washed activated fly ash, continue stirring for 30-40 min, reduce the stirring rate, add modified anionic polyacrylamide in 2-3 batches, stir for 15-20 min to obtain a mixed slurry; S6: Pump the mixed slurry into a pressure spray drying tower, dry and sieve to obtain wastewater treatment agent.

2. The method for preparing the wastewater treatment agent according to claim 1, characterized in that, S1 specifically involves mixing fly ash with 5-8% industrial hydrochloric acid at a solid-liquid ratio of 1:10-12, stirring at room temperature for 60-90 minutes, filtering by plate and frame press, washing with industrial water until the pH reaches 6-7, drying with hot air at 105-110℃ for 4-6 hours, and pulverizing to 200 mesh to obtain acid-washed activated fly ash.

3. The method for preparing the wastewater treatment agent according to claim 1, characterized in that, S2 specifically involves drying polyaluminum ferric chloride, sodium aluminate, and magnesium hydroxide separately in hot air at 100-120℃ for 2-3 hours, and then pulverizing them to below 200 mesh.

4. The method for preparing the wastewater treatment agent according to claim 1, characterized in that, S3 specifically consists of: 45-75 parts by weight of anionic polyacrylamide, 10-20 parts by weight of dimethyl diallyl ammonium chloride, 5-10 parts by weight of sodium lignosulfonate, and 1-3 parts by weight of potassium dihydrogen phosphate. Anionic polyacrylamide was added to 640-840 parts of deionized water and stirred at 100-200 r / min for 30-60 min at 25-35℃ to prepare an aqueous solution of anionic polyacrylamide. Sodium lignosulfonate and potassium dihydrogen phosphate are added to 160-360 parts of deionized water and stirred at 40-50℃ for 20-30 minutes to obtain a composite additive. Heating anionic polyacrylamide aqueous solution to 50-60℃, adding dimethyl diallyl ammonium chloride dropwise at 1-2 mL / s, stirring at 200-300 r / min for 40-60 min, adding composite additives, reducing the stirring rate to 150-250 r / min, stirring for 60-90 min, adjusting the pH to 7.5-8.5 with sodium hydroxide solution, cooling to 25-30℃ at 1-2℃ / min, stirring for 10-15 min, to obtain the modified reaction solution; The modified reaction solution is placed in a vacuum concentration tank and concentrated for 30-50 minutes under a vacuum of 0.04-0.07 MPa and a temperature of 50-60°C to obtain a concentrated solution with 10-15% of the original volume. The concentrated solution is then pumped into a pressure spray drying tower, with the inlet temperature controlled at 180-200°C, the outlet temperature at 80-90°C, and the atomization pressure at 0.2 MPa-0.4 MPa, to obtain modified anionic polyacrylamide.

5. The method for preparing the wastewater treatment agent according to claim 1, characterized in that, S5 is specifically as follows: Add 3-7 parts of deionized water to an industrial mixing tank, heat to 40-50℃ at 2-4℃ / min, keep at the temperature for 20-30min, stir at 300-500r / min, add sodium aluminate all at once, stir for 20-30min, add polyaluminum ferric chloride and magnesium hydroxide in sequence, with an interval of 10-15min, stir for 40-60min, add acid-washed activated fly ash, continue stirring for 30-40min, reduce the stirring speed to 200-300r / min, add modified anionic polyacrylamide in 2-3 portions, with an interval of 5-8min, stir for 15-20min to obtain a mixed slurry.

6. The method for preparing the wastewater treatment agent according to claim 1, characterized in that, S6 specifically involves pumping the mixed slurry into a pressure spray drying tower, controlling the inlet temperature at 200-220℃, the outlet temperature at 90-100℃, and the atomization pressure at 0.3-0.5MPa, and then drying and sieving to obtain the wastewater treatment agent.

7. A wastewater treatment agent prepared by the preparation method according to any one of claims 1-6.

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