Zero discharge process and equipment for silicon steel reverse osmosis concentrate, filter material, adsorbent and preparation method thereof

Abstract

The application provides a zero discharge process and equipment for silicon steel reverse osmosis concentrated solution, and a filter material, an adsorbent and a preparation method thereof, and the water quality of the concentrated solution is as follows: soluble COD 22-31 mg / L, turbidity 34-53 NTU, calcium ion 17-29 mg / L, silicon ion 4-14 mg / L, and conductivity 81600-113890 muS / cm; the process comprises the following steps: 1, the concentrated solution to be treated firstly enters a modified filter tower, and modified iron slag-activated carbon filter material is placed in the modified filter tower; after passing through the modified filter tower, the soluble COD of the concentrated solution is 4-6 mg / L, the turbidity is 3-7 NTU, the calcium ion is 13-26 mg / L, and the silicon ion is 2-7 mg / L; 2, then the concentrated solution enters a resin adsorption tower through a lifting pump, modified chelating resin adsorbent is placed in the resin adsorption tower, the soluble COD of the concentrated solution is 2-4 mg / L, the turbidity is 1-5 NTU, the calcium ion is 1-3 mg / L, and the silicon ion is 0.2-0.7 mg / L; 3, then the concentrated solution is pumped into a bipolar membrane system by the lifting pump to change the concentrated solution into acid and alkali; the current efficiency of the bipolar membrane system is 71-84%, the concentration of the produced hydrochloric acid is 1.07-1.16 mol / L, and the concentration of the produced sodium hydroxide is 1.01-1.06 mol / L.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of process wastewater treatment, and particularly relates to a zero-discharge process for silicon steel reverse osmosis concentrated liquid, a device thereof, and filter material and adsorbent thereof as well as a preparation method of the filter material and the adsorbent. BACKGROUND

[0002] The silicon steel wastewater system generated by the production line of non-oriented silicon steel and oriented silicon steel mainly comprises an acid wastewater treatment system, a dilute alkali wastewater treatment system, a concentrated alkali oil-containing wastewater treatment system, and a heavy metal chromium wastewater treatment system, and the wastewater treated by each system is collected and discharged in accordance with the standard.

[0003] Wastewater reuse is the ultimate goal of wastewater treatment and an implementation means of energy saving and emission reduction of enterprises. The silicon steel wastewater treated by the conventional treatment is discharged in accordance with the standard. In order to reduce wastewater discharge, the reverse osmosis technology is used to treat the silicon steel wastewater discharged in accordance with the standard, and the reverse osmosis production water can be applied to production. The content of organic matter and silicon in the silicon steel reverse osmosis concentrated liquid is high, and after the organic matter and silicon ions and other impurities in the silicon steel reverse osmosis concentrated liquid are removed, the silicon steel reverse osmosis concentrated liquid can realize zero wastewater discharge.

[0004] However, so far, there is no zero-discharge process for simultaneously removing the silicon steel reverse osmosis concentrated liquid. SUMMARY

[0005] The technical problem to be solved by the application is to develop an economic and efficient resource treatment process according to the water quality and quantity of the silicon steel reverse osmosis concentrated liquid, to take energy saving and emission reduction as the main task, and to reduce environmental pollution.

[0006] The technical problem to be solved by the application can be solved by the following technical scheme.

[0007] A zero-discharge process for silicon steel reverse osmosis concentrated liquid, wherein the water quality characteristics of the silicon steel reverse osmosis concentrated liquid are as follows:

[0008] The soluble COD is 22-31 mg / L, the turbidity is 34-53 NTU, the calcium ion is 17-29 mg / L, the silicon ion is 4-14 mg / L, and the conductivity is 81600-113890 μS / cm;

[0009] The process comprises the following treatment steps:

[0010] (1) The concentrated liquid to be treated first enters a modified filter tower, and a modified iron slag-activated carbon filter material is arranged in the modified filter tower; after passing through the modified filter tower, the soluble COD of the silicon steel reverse osmosis concentrated liquid is 4-6 mg / L, the turbidity is 3-7 NTU, the calcium ion is 13-26 mg / L, and the silicon ion is 2-7 mg / L;

[0011] (2) The silicon steel reverse osmosis concentrate is then pumped into the resin adsorption tower by the lifting pump, and the modified chelating resin adsorbent is placed in the resin adsorption tower. The solubility COD of the silicon steel reverse osmosis concentrate is 2-4 mg / L, the turbidity is 1-5 NTU, the calcium ion is 1-3 mg / L, and the silicon ion is 0.2-0.7 mg / L;

[0012] (3) The silicon steel reverse osmosis concentrate is then pumped into the bipolar membrane system by the concentrate lifting pump to change the silicon steel reverse osmosis concentrate into acid and alkali. The current efficiency of the bipolar membrane system is 71-84%, the concentration of the produced hydrochloric acid is 1.07-1.16 mol / L, and the concentration of the produced sodium hydroxide is 1.01-1.06 mol / L.

[0013] As a further improvement of the technical solution, the modified iron slag-activated carbon filter material accounts for 85-95% of the volume of the modified filter tower; and the residence time of the silicon steel reverse osmosis concentrate in the modified filter tower is 17-28 min.

[0014] 80-90% of the volume of the adsorption system in the resin adsorption tower is occupied by the modified chelating resin adsorbent.

[0015] As a further improvement of the technical solution, the modified iron slag-activated carbon filter material is backwashed after being operated for 620-740 h, and the backwashing time is 4-10 min.

[0016] As a further improvement of the technical solution, the modified iron slag-activated carbon filter material is prepared by the following method:

[0017] 1) Screening D 50 iron slag with a size of 1.2-2.5 mm and D 50 chitosan with a size of 1.2-2.5 mm;

[0018] 2) Prepare a hydrochloric acid solution with a mass ratio of 3-4%, and add 45-92 g of iron slag, 42-56 g of screened activated carbon, and 2-3 g of aluminum sulfate to each liter of the hydrochloric acid solution, and stir;

[0019] 3) Take out the mixed filter material, dry it at 105°C, and form the modified iron slag-activated carbon filter material.

[0020] Further, in step 2), mechanical stirring is performed at a speed of 46-55 rpm for 30-45 min.

[0021] As a further improvement of the technical solution, the modified chelating resin adsorbent is prepared by the following method:

[0022] 1) Selection and dissolution of polymer:

[0023] Chloromethyl polystyrene is selected, and the crosslinking degree is between 9-11%;

[0024] 2) Pour dichloroethane into the reaction kettle, add 12-25 g of chloromethyl polystyrene and 6-11 g of p-dichloromethyl biphenyl per liter of dichloroethane solution, and stand until the chloromethyl polystyrene is fully swollen to form a mixture;

[0025] 3) Then cool the mixture to 0-3℃, add 4-26 mL of tin tetrachloride per liter of dichloroethane solution under stirring, heat the reaction kettle to 72-81℃, react for 150-235 min, cool, filter, wash the mixture with water for 3-5 times, wash with petroleum ether for 3-5 times, and perform first vacuum drying to form a chloromethyl polystyrene mixed polymer;

[0026] 4) Add N,N-dimethylformamide solution into the reaction kettle according to the size of the reaction kettle, add 1-3 mL of N,N,N,N-tetramethyl malonamide per liter of N,N-dimethylformamide solution dropwise, heat the reaction kettle to 52-57℃, and keep the temperature for 65-85 min, and then cool to form an N,N-dimethylformamide solution mixed solution;

[0027] 5) Add 13-17 g of chloromethyl polystyrene mixed polymer per liter of N,N-dimethylformamide solution mixed solution, heat the reaction kettle to 76-78℃ after swelling, react for 21-23 h under stirring, cool, filter, wash with petroleum ether for 3-5 times, wash with n-hexane for 3-5 times, wash with clean water for 3-5 times, and perform second vacuum drying to form a modified chelating resin containing chloromethyl polystyrene.

[0028] Further, the first vacuum drying and the second vacuum drying are performed at a temperature condition of 60℃.

[0029] Another technical problem to be solved by the present application is to provide a device for implementing the zero-discharge process of the foregoing silicon steel reverse osmosis concentrated solution, which is sequentially connected with a water inlet pump, a modified filter tower, a lifting pump, a resin adsorption tower, a concentrated solution lifting pump and a bipolar membrane system in the flow direction of the concentrated solution; the modified filter tower is placed with modified iron slag-activated carbon filter material; and the resin adsorption tower is provided with a modified chelating resin adsorbent.

[0030] Still another technical problem to be solved by the present application is to provide a preparation method of the modified iron slag-activated carbon filter material in the foregoing zero-discharge process, which adopts the following preparation steps:

[0031] 1) Screen D 50 iron slag with a size of 1.2-2.5 mm and D 50 chitosan with a size of 1.2-2.5 mm;

[0032] 2), configuration of hydrochloric acid solution quality ratio is 3~4%, in every liter of hydrochloric acid solution, add 45~92 g of iron slag, 42~56 g of screened activated carbon and 2~3 g of aluminum sulfate, and stir;

[0033] 3), take out the mixed filter material, dry at 105 DEG C, and form modified iron slag-activated carbon filter material.

[0034] The application also provides a filter material obtained by the preparation method.

[0035] Another technical problem to be solved by the application is to provide a preparation method of a modified chelating resin adsorbent in the foregoing zero-emission process, which comprises the following preparation steps:

[0036] 1), selection and dissolution of polymer:

[0037] Chloromethyl polystyrene is selected, and the crosslinking degree is between 9~11%;

[0038] 2), pour dichloroethane into the reaction kettle, add 12~25 g of chloromethyl polystyrene and 6~11 g of p-dichloromethyl biphenyl per liter of dichloroethane solution, and stand until the chloromethyl polystyrene is fully swollen to form a mixture;

[0039] 3), then cool the mixture to 0~3 DEG C, add 4~26 mL of tin tetrachloride per liter of dichloroethane solution under stirring, heat the reaction kettle to 72~81 DEG C, react for 150~235 min, cool, filter, wash the mixture with water for 3~5 times, wash with petroleum ether for 3~5 times, and perform first vacuum drying to form a chloromethyl polystyrene mixed polymer;

[0040] 4), add N,N-dimethylformamide solution to the reaction kettle according to the size of the reaction kettle, add 1~3 mL of N,N,N,N-tetramethyl malonamide per liter of N,N-dimethylformamide solution, heat the reaction kettle to 52~57 DEG C, and keep the temperature constant for 65~85 min, and then cool to form an N,N-dimethylformamide solution mixed solution;

[0041] 5), add 13~17 g of chloromethyl polystyrene mixed polymer per liter of N,N-dimethylformamide solution mixed solution, heat the reaction kettle to 76~78 DEG C after swelling, react for 21~23 h under stirring, cool, filter, wash with petroleum ether for 3~5 times, wash with n-hexane for 3~5 times, wash with clean water for 3~5 times, and perform second vacuum drying to form a modified chelating resin containing chloromethyl polystyrene.

[0042] The application also provides an adsorbent obtained by the preparation method.

[0043] The process system has low one-time investment, simple operation, low production processing cost and is an environment-friendly green development process. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A device diagram of the zero discharge process of the silicon steel reverse osmosis concentrated solution;

[0045] In the figure: 1 - water pump, 2 - modified filter tower, 3 - modified quartz sand-activated carbon filter material, 4 - lifting pump, 5 - resin adsorption tower, 6 - modified chelating resin adsorbent, 7 - concentrated solution lifting pump, 8 - bipolar membrane system. DETAILED DESCRIPTION

[0046] The present application provides a kind of process and equipment of zero discharge of silicon steel reverse osmosis concentrated solution, and the equipment mainly includes water pump 1, modified filter tower 2, modified quartz sand-activated carbon filter material 3, lifting pump 4, resin adsorption tower 5, modified chelating resin adsorbent 6, concentrated solution lifting pump 7 and bipolar membrane system 8.

[0047] The water quality of the silicon steel reverse osmosis concentrated solution: the soluble COD is 22-31 mg / L, the turbidity is 34-53 NTU, the calcium ion is 17-29 mg / L, the silicon ion is 4-14 mg / L, and the conductivity is 81600-113890 μS / cm.

[0048] The silicon steel reverse osmosis concentrated solution enters the modified filter tower 2 through the water pump 1, and the function of the modified filter tower 2 is to remove the impurities and soluble COD of the silicon steel reverse osmosis concentrated solution. Modified iron slag-activated carbon filter material 3 (or in the form of filter material placed in the modified filter tower) is placed in the modified filter tower, and the modified iron slag-activated carbon filter material 3 accounts for 85-95% of the volume of the modified filter tower 2. The residence time of the silicon steel reverse osmosis concentrated solution in the modified filter tower is 17-28 min, and the modified iron slag-activated carbon filter material is backwashed after running for 620-740 h, and the backwashing time is 4-10 min. After passing through the modified filter tower, the soluble COD of the silicon steel reverse osmosis concentrated solution is 4-6 mg / L, the turbidity is 3-7 NTU, the calcium ion is 13-26 mg / L, and the silicon ion is 2-7 mg / L. After passing through the modified filter tower, the impurities and soluble COD in the silicon steel reverse osmosis concentrated solution are greatly reduced, so that the impurities and soluble COD in the silicon steel reverse osmosis concentrated solution can not affect the subsequent zero discharge system.

[0049] The modified iron slag-activated carbon filter material 3 is prepared according to the characteristics of the silicon steel reverse osmosis concentrated solution. The preparation method of the iron slag-activated carbon filter material is as follows:

[0050] 1) screening D 50iron slag with size of 1.2~2.5 mm and D 50 chitosan with size of 1.2~2.5 mm;

[0051] 2) A hydrochloric acid solution with mass ratio of 3~4% is configured, 45~92 g of iron slag, 42~56 g of screened activated carbon, and 2~3 g of aluminum sulfate are added into each liter of the hydrochloric acid solution, and mechanical stirring is performed at a speed of 46~55 r / min for 30~45 min;

[0052] 3) The mixed filter material is taken out and dried at 105℃ to form modified iron slag-activated carbon filter material. During the modification process, the activated carbon is loaded on the surface of the iron slag to form a new type of adsorption particle with the iron slag, and the iron slag skeleton structure can adsorb more organic matter and various ions to effectively remove impurities in the silicon steel reverse osmosis concentrated solution. Through testing, the saturation adsorption capacity of the modified iron slag-activated carbon filter material for soluble COD is 12~17 mg / g under a salt concentration of 100000 μS / cm.

[0053] Subsequently, the silicon steel reverse osmosis concentrated solution enters the resin adsorption tower 5 through the lifting pump 4, and the modified chelating resin adsorbent 6 is placed in the resin adsorption tower 5. In the adsorption system, 80~90% of the volume is occupied by the modified chelating resin adsorbent, the soluble COD of the silicon steel reverse osmosis concentrated solution is 2~4 mg / L, the turbidity is 1~5 NTU, the calcium ion is 1~3 mg / L, and the silicon ion is 0.2~0.7 mg / L.

[0054] Among them, the modified chelating resin adsorbent is prepared according to the characteristics of the silicon steel reverse osmosis concentrated solution. The preparation steps are as follows:

[0055] 1) Selection and dissolution of polymer: chloromethyl polystyrene with crosslinking degree of 9~11% is selected.

[0056] 2) Pour dichloroethane into the reaction kettle, add 12~25 g of chloromethyl polystyrene and 6~11 g of p-dichloromethyl biphenyl into each liter of dichloroethane solution, stand for 2~5 h, and the chloromethyl polystyrene is fully swollen to form a mixture.

[0057] 3) Then cool the mixture to 0~3℃, add 4~26 mL of tin tetrachloride under stirring, heat the reaction kettle to 72~81℃, react for 150~235 min, naturally cool, filter, wash the mixture with water for 3~5 times, wash with petroleum ether for 3~5 times, and vacuum dry at 60℃ to form a chloromethyl polystyrene mixed polymer.

[0058] 4) Add N,N-dimethylformamide solution into the reactor, add 1-3 mL of N,N,N,N-tetramethylmalonamide into every liter of N,N-dimethylformamide solution, heat the reactor to 52-57℃, keep the temperature for 65-85 min, then cool down, and form a mixed solution of N,N-dimethylformamide solution.

[0059] 5) Add 13-17 g of chloromethyl polystyrene mixed polymer into every liter of the mixed solution of N,N-dimethylformamide solution, after swelling, heat the reactor to 76-78℃, react for 21-23 h under stirring, cool down naturally, filter, wash 3-5 times with petroleum ether, wash 3-5 times with n-hexane, wash 3-5 times with clean water, and form a modified chelating resin containing chloromethyl polystyrene after vacuum drying at 60℃. The micropore volume of the modified chelating resin is 0.28-0.31 cm 3 / g, and it has strong adsorption capacity for calcium and silicon.

[0060] Then the concentrated solution lifting pump 7 pumps the silicon steel reverse osmosis concentrated solution into the bipolar membrane system 8, and the bipolar membrane system 8 can change the silicon steel reverse osmosis concentrated solution into acid and alkali. Because the water quality requirement of the bipolar membrane system is high, the silicon steel reverse osmosis concentrated solution must remove impurities such as organic matter and calcium and silicon before entering the bipolar membrane system, so that the quality of the produced acid and alkali can be high. The current efficiency of the bipolar membrane system is 71-84%, the produced hydrochloric acid has a concentration of 1.07-1.16 mol / L, and the produced sodium hydroxide has a concentration of 1.01-1.06 mol / L.

[0061] The acid and alkali produced by the bipolar membrane system are applied to industrial systems, so the present application belongs to a green and environmentally friendly process, and has good social and environmental benefits.

[0062] In order to better understand the present application, the content of the present application will be further illustrated below in combination with specific examples, but the content of the present application is not limited to the following examples.

[0063] Example 1:

[0064] In this example, the water quality of the silicon steel reverse osmosis concentrated solution is as follows: the soluble COD is 31 mg / L, the turbidity is 53 NTU, the calcium ion is 27 mg / L, the silicon ion is 11 mg / L, and the conductivity is 109870 μS / cm.

[0065] The silicon steel reverse osmosis concentrate is pumped into the modified filter tower by the water inlet pump. The function of the modified filter tower is to remove the impurities and soluble COD of the silicon steel reverse osmosis concentrate. The modified iron slag-activated carbon filter material is placed in the modified filter tower, and the modified iron slag-activated carbon filter material accounts for 95% of the volume of the modified filter tower. The residence time of the silicon steel reverse osmosis concentrate in the modified filter tower is 28 min. The modified iron slag-activated carbon filter material is backwashed after running for 620 h, and the backwashing time is 10 min. After passing through the modified filter tower, the soluble COD of the silicon steel reverse osmosis concentrate is 6 mg / L, the turbidity is 7 NTU, the calcium ion is 23 mg / L, and the silicon ion is 7 mg / L. After passing through the modified filter tower, the impurities and soluble COD in the silicon steel reverse osmosis concentrate are greatly reduced, so that the impurities and soluble COD in the silicon steel reverse osmosis concentrate do not affect the subsequent zero discharge system.

[0066] The modified iron slag-activated carbon filter material is prepared according to the characteristics of the silicon steel reverse osmosis concentrate. In this embodiment, the preparation of the iron slag-activated carbon filter material is as follows:

[0067] 1) Screen the iron slag with a D50 of 2.5 mm and the chitosan with a D50 of 2.5 mm;

[0068] 2) Prepare a hydrochloric acid solution with a mass ratio of 4%, and add 92 g of iron slag, 56 g of screened activated carbon, and 3 g of aluminum sulfate to each liter of the hydrochloric acid solution. Mechanically stir at a speed of 55 revolutions per minute for 45 minutes;

[0069] 3) Take out the mixed filter material and dry it at 105°C to form the modified iron slag-activated carbon filter material. During the modification process, the activated carbon is loaded on the surface of the iron slag, forming a new type of adsorption particle with the iron slag. The iron slag skeleton structure can adsorb more organic matter and various ions, effectively removing the impurities in the silicon steel reverse osmosis concentrate. Through testing, the saturated adsorption capacity of the modified iron slag-activated carbon filter material for soluble COD is 17 mg / g under a salt concentration of 100,000 μS / cm.

[0070] Subsequently, the silicon steel reverse osmosis concentrate is pumped into the resin adsorption tower by the lifting pump. The modified chelating resin adsorbent is placed in the resin adsorption tower. 90% of the volume of the adsorption system is occupied by the modified chelating resin adsorbent. The soluble COD of the silicon steel reverse osmosis concentrate is 4 mg / L, the turbidity is 5 NTU, the calcium ion is 3 mg / L, and the silicon ion is 0.7 mg / L.

[0071] The modified chelating resin adsorbent is prepared according to the characteristics of the silicon steel reverse osmosis concentrate. In this embodiment, the preparation of the modified chelating resin adsorbent is as follows:

[0072] 1) Selection and dissolution of polymer: Select chloromethyl polystyrene with a crosslinking degree of 11%.

[0073] 2) Pour dichloroethane into the reactor, add 25 g of chloromethyl polystyrene and 11 g of p-dichloromethyl biphenyl per liter of dichloroethane solution, stand for 5 h, and allow the chloromethyl polystyrene to swell completely to form a mixture.

[0074] 3) Then cool the mixture to 0°C, add 26 mL of tin tetrachloride under stirring, raise the temperature of the reactor to 81°C, react for 235 min, cool naturally, filter, wash the mixture with water 5 times and with petroleum ether 5 times, and dry under vacuum at 60°C to form a chloromethyl polystyrene mixed polymer.

[0075] 4) Add N,N-dimethylformamide solution into the reactor, add 3 mL of N,N,N,N-tetramethyl malonamide per liter of N,N-dimethylformamide solution, raise the temperature of the reactor to 57°C, and maintain the temperature for 85 min, then cool to form an N,N-dimethylformamide solution mixed solution.

[0076] 5) Add 17 g of chloromethyl polystyrene mixed polymer per liter of N,N-dimethylformamide solution mixed solution, raise the temperature of the reactor to 78°C after swelling, react for 23 h under stirring, cool naturally, filter, wash with petroleum ether 4 times, n-hexane 5 times, and clean water 4 times, and dry under vacuum at 60°C to form a modified chelating resin containing chloromethyl polystyrene. The modified chelating resin has a micropore volume of 0.31 cm 3 / g, and has strong adsorption capacity for calcium and silicon.

[0077] The concentrated solution is then pumped into the bipolar membrane system by a booster pump, and the bipolar membrane system can convert the silicon steel reverse osmosis concentrated solution into acid and base. Because the bipolar membrane system has high water quality requirements, the silicon steel reverse osmosis concentrated solution must be removed of impurities such as organic matter and calcium and silicon before entering the bipolar membrane system, so that the quality of the generated acid and base can be high. The bipolar membrane system has a current efficiency of 82%, produces hydrochloric acid with a concentration of 1.16 mol / L, and produces sodium hydroxide with a concentration of 1.06 mol / L.

[0078] Example 2:

[0079] In this example, the water quality of the silicon steel reverse osmosis concentrated solution is: soluble COD is 25 mg / L, turbidity is 42 NTU, calcium ion is 19 mg / L, silicon ion is 6 mg / L, and conductivity is 93400 μS / cm.

[0080] The silicon steel reverse osmosis concentrate is pumped into the modified filter tower by the water inlet pump. The function of the modified filter tower is to remove the impurities and soluble COD of the silicon steel reverse osmosis concentrate. The modified iron slag-activated carbon filter material is placed in the modified filter tower, and the modified iron slag-activated carbon filter material accounts for 85-95% of the volume of the modified filter tower. The residence time of the silicon steel reverse osmosis concentrate in the modified filter tower is 19 min. The modified iron slag-activated carbon filter material is backwashed after running for 650 h, and the backwashing time is 5 min. After passing through the modified filter tower, the soluble COD of the silicon steel reverse osmosis concentrate is 4 mg / L, the turbidity is 4 NTU, the calcium ion is 16 mg / L, and the silicon ion is 3 mg / L. After passing through the modified filter tower, the impurities and soluble COD in the silicon steel reverse osmosis concentrate are greatly reduced, which can ensure that the impurities and soluble COD in the silicon steel reverse osmosis concentrate do not affect the subsequent zero-emission system.

[0081] The modified iron slag-activated carbon filter material is prepared according to the characteristics of the silicon steel reverse osmosis concentrate. The preparation of the iron slag-activated carbon filter material is as follows:

[0082] 1) Selecting iron slag with D50 of 1.2 mm and chitosan with D50 of 1.2 mm;

[0083] 2) Preparing a hydrochloric acid solution with a mass ratio of 3%, adding 49 g of iron slag, 43 g of the selected activated carbon, and 2 g of aluminum sulfate per liter of the hydrochloric acid solution, and mechanically stirring at a speed of 46 revolutions per minute for 30 min;

[0084] 3) Taking out the mixed filter material, drying it at 105°C, and forming the modified iron slag-activated carbon filter material. During the modification process, the activated carbon is loaded on the surface of the iron slag, forming a new type of adsorption particle with the iron slag. The iron slag skeleton structure can adsorb more organic matter and various ions, effectively removing the impurities in the silicon steel reverse osmosis concentrate. After testing, the saturation adsorption capacity of the modified iron slag-activated carbon filter material for soluble COD is 14 mg / g under a salt concentration of 100000 μS / cm.

[0085] Subsequently, the silicon steel reverse osmosis concentrate is pumped into the resin adsorption tower by the lifting pump. The modified chelating resin adsorbent is placed in the resin adsorption tower. 85% of the volume of the adsorption system is occupied by the modified chelating resin adsorbent. The soluble COD of the silicon steel reverse osmosis concentrate is 2 mg / L, the turbidity is 2 NTU, the calcium ion is 1 mg / L, and the silicon ion is 0.3 mg / L.

[0086] The modified chelating resin adsorbent is prepared according to the characteristics of the silicon steel reverse osmosis concentrate. The preparation of the modified chelating resin adsorbent is as follows:

[0087] 1) Selection and dissolution of polymer: selecting chloromethyl polystyrene with a crosslinking degree of 9%;

[0088] 2) Pour dichloroethane into the reactor, add 16 g of chloromethyl polystyrene and 7 g of p-dichloromethyl biphenyl per liter of dichloroethane solution, stand for 3 h, and allow the chloromethyl polystyrene to swell fully to form a mixture.

[0089] 3) Then cool the mixture to 2°C, add 6 mL of tin tetrachloride under stirring, raise the temperature of the reactor to 74°C, react for 175 min, cool naturally, filter, wash the mixture with water 3 times, wash with petroleum ether 3 times, and dry under vacuum at 60°C to form a chloromethyl polystyrene mixed polymer.

[0090] 4) Add N,N-dimethylformamide solution into the reactor, add 1 mL of N,N,N,N-tetramethyl malonamide per liter of N,N-dimethylformamide solution, raise the temperature of the reactor to 55°C, and keep the temperature constant for 69 min, then cool to form an N,N-dimethylformamide solution mixed solution.

[0091] 5) Add 14 g of chloromethyl polystyrene mixed polymer per liter of N,N-dimethylformamide solution mixed solution, raise the temperature of the reactor to 76°C after swelling, react for 21 h under stirring, cool naturally, filter, wash with petroleum ether 3 times, wash with n-hexane 3 times, wash with clean water 3 times, and dry under vacuum at 60°C to form a modified chelating resin containing chloromethyl polystyrene. The modified chelating resin has a micropore volume of 0.29 cm 3 / g, and has strong adsorption capacity for calcium and silicon.

[0092] The concentrated solution is then pumped into the bipolar membrane system by a booster pump, and the bipolar membrane system can convert the silicon steel reverse osmosis concentrated solution into acid and base. Because the bipolar membrane system has high water quality requirements, the silicon steel reverse osmosis concentrated solution must be removed of impurities such as organic matter and calcium and silicon before entering the bipolar membrane system, so that the quality of the generated acid and base can be high. The bipolar membrane system has a current efficiency of 74%, produces hydrochloric acid with a concentration of 1.09 mol / L, and produces sodium hydroxide with a concentration of 1.02 mol / L.

[0093] Of course, those skilled in the art should recognize that the above embodiments are only used to illustrate the present application, and are not used as a limitation on the present application, and as long as the above embodiments are changed and deformed within the scope of the spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A zero discharge process of silicon steel reverse osmosis concentrate, the silicon steel reverse osmosis concentrate water quality features are as follows: soluble COD 22~31 mg / L, turbidity 34~53 NTU, calcium ion 17~29 mg / L, silicon ion 4~14 mg / L, conductivity 81600~113890 μS / cm; comprising the following processing steps: (1), the concentrate to be treated first enters the modified filter tower, the modified filter tower is placed with modified iron slag-activated carbon filter material; after passing through the modified filter tower, the soluble COD of the silicon steel reverse osmosis concentrate is 4~6 mg / L, the turbidity is 3~7 NTU, the calcium ion is 13~26 mg / L, and the silicon ion is 2~7 mg / L; the modified iron slag-activated carbon filter material is prepared by the following method: 2), a hydrochloric acid solution with a mass ratio of 3~4% is configured, 45~92 g of iron slag, 42~56 g of screened activated carbon and 2~3 g of aluminum sulfate are added in each liter of hydrochloric acid solution, and stirring is performed; 3), the mixed filter material is taken out, dried at 105°C, and the modified iron slag-activated carbon filter material is formed; (2), then the silicon steel reverse osmosis concentrate enters the resin adsorption tower through the lifting pump, the modified chelating resin adsorbent is placed in the resin adsorption tower, the soluble COD of the silicon steel reverse osmosis concentrate is 2~4 mg / L, the turbidity is 1~5 NTU, the calcium ion is 1~3 mg / L, and the silicon ion is 0.2~0.7 mg / L; the modified chelating resin adsorbent is prepared by the following method: 1), selection and dissolution of polymer: chloromethyl polystyrene is selected, and the crosslinking degree is between 9~11%; 2), dichloroethane is poured into the reaction kettle, 12~25 g of chloromethyl polystyrene and 6~11 g of p-dichloromethyl benzene are added in each liter of dichloroethane solution, and the mixture is formed after the chloromethyl polystyrene is fully swelled; 3), then the temperature of the mixture is cooled to 0~3°C, 4~26 mL of tin tetrachloride is added in each liter of dichloroethane solution under stirring, the reaction kettle is heated to 72~81°C, the reaction is performed for 150~235 min, and then the mixture is cooled, filtered, washed with water for 3~5 times, washed with petroleum ether for 3~5 times, and vacuum dried for the first time to form a chloromethyl polystyrene mixed polymer; 4), N,N-dimethylformamide solution is added to the reaction kettle, 1~3 mL of N,N,N',N'-tetramethyl malonamide is added dropwise in each liter of N,N-dimethylformamide solution, the reaction kettle is heated to 52~57°C, and then the temperature is kept for 65~85 min, and then the N,N-dimethylformamide solution mixed solution is formed after cooling; 5), 13~17 g of chloromethyl polystyrene mixed polymer is added in each liter of N,N-dimethylformamide solution mixed solution, the reaction kettle is heated to 76~78°C after swelling, the reaction is performed for 21~23 h under stirring, and then the mixture is cooled, filtered, washed with petroleum ether for 3~5 times, washed with n-hexane for 3~5 times, washed with clean water for 3~5 times, and vacuum dried for the second time to form a modified chelating resin containing chloromethyl polystyrene. ​ characterized in that ​ ​ ​ 1) screening D 50 iron slag having a size of 1.2 to 2.5 mm and D 50 chitosan having a size of 1.2 to 2.5 mm; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (3), then the concentrated liquid lifting pump into the bipolar membrane system to the silicon steel reverse osmosis concentrated liquid into acid and alkali; bipolar membrane system current efficiency of 71~84%, the production of hydrochloric acid concentration 1.07~1.16 mol / L, the production of sodium hydroxide concentration 1.01~1.06 mol / L.

2. The process for zero liquid discharge of reverse osmosis concentrate of silicon steel as claimed in claim 1 wherein, The modified iron slag-activated carbon filter material accounts for 85~95% of the volume of the modified filter tower; the residence time of the silicon steel reverse osmosis concentrated liquid in the modified filter tower is 17~28 min; 80~90% of the volume of the adsorption system in the resin adsorption tower is placed with modified chelating resin adsorbent.

3. The process for zero liquid discharge of reverse osmosis concentrate of silicon steel as claimed in claim 1 wherein, The modified iron slag-activated carbon filter material is backwashed after running for 620~740 h, and the backwashing time is 4~10 min.

4. The process for zero liquid discharge of reverse osmosis concentrate of silicon steel as claimed in claim 1 wherein, In step 2) of the preparation method of the modified iron slag-activated carbon filter material, mechanical stirring is carried out at a speed of 46~55 r / min for 30~45 min.

5. The process for zero liquid discharge of reverse osmosis concentrate of silicon steel as claimed in claim 1 wherein, The first vacuum drying and the second vacuum drying are carried out at a temperature of 60℃.

6. An apparatus for implementing the zero liquid discharge process of the reverse osmosis concentrate of silicon steel according to any one of claims 1-5, characterized in that, In the direction of the flow of the concentrated liquid, a water inlet pump, a modified filter tower, a lifting pump, a resin adsorption tower, a concentrated liquid lifting pump and a bipolar membrane system are sequentially connected; the modified filter tower is placed with the modified iron slag-activated carbon filter material; the resin adsorption tower is provided with the modified chelating resin adsorbent.

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