Water treatment method after secondary aluminum ash hydrogen production

Abstract

The invention relates to the technical field of industrial solid waste comprehensive treatment, and discloses a water treatment method and system after secondary aluminum ash hydrogen production, and the method comprises the following steps: collecting hydrolysate after secondary aluminum ash hydrogen production to obtain high saline-alkaline ammonia nitrogen hydrolysate; carrying out ammonia-nitrogen separation on the high-salt-alkali ammonia-nitrogen hydrolysate to obtain a gas phase and a first-stage liquid phase; dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase; dissolving carbon dioxide in the second-stage liquid phase until the specified pH value is reached to obtain a third-stage liquid phase; adding an extracting solvent into the third-stage liquid phase, dissolving carbon dioxide until the specified pH value is reached, and extracting and separating to obtain a fourth-stage liquid phase of an organic phase and a fourth-stage liquid phase of an inorganic phase; evaporating moisture of a fourth-stage liquid phase of the inorganic phase; and carrying out back extraction separation on the fourth-stage liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase. By adopting the method, aluminum hydroxide and various valuable salts can be efficiently recovered, and the obtained product is rich and high in value.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive disposal of industrial solid waste, and in particular to a method for treating water after secondary hydrogen production from aluminum ash. Background Art

[0002] Aluminum ash is a hazardous solid waste produced in the aluminum industry. The main components and contents (mass fraction) of aluminum ash are: 10%-30% of elemental aluminum; 20%-40% of aluminum oxide; 7%-15% of silicon, magnesium and iron oxides; 15%-30% of potassium, sodium, calcium and magnesium chlorides and other trace fluorides. According to the number of times aluminum ash is used in the recycling process and the content of elemental aluminum, aluminum ash can be divided into primary aluminum ash and secondary aluminum ash. Primary aluminum ash is a kind of slag that is not soluble in aluminum liquid during the production of primary aluminum by electrolytic aluminum oxide. The elemental aluminum content in primary aluminum ash is 30%-85%. In addition, it also contains substances such as fluoride salts, aluminum oxide and aluminum nitride.

[0003] Secondary aluminum ash is the ash produced in the process of remelting primary aluminum ash or waste aluminum to recover elemental aluminum in the secondary aluminum industry. The elemental aluminum content in secondary aluminum ash is between 5% and 20%. In addition, it also contains aluminum oxide, aluminum nitride, salt (fluoride salt and chloride salt, etc.) and silicon dioxide.

[0004] The main hazards of secondary aluminum ash are aluminum nitride, and a small amount of inorganic salt components such as fluoride, sulfide, sulfate and chloride. Direct discharge will cause serious air, soil and water pollution. The disposal methods of secondary aluminum ash are mainly divided into pyrolysis and wet method (mainly hydrolysis). The wet method includes acid-base treatment, which is to react the secondary aluminum ash with a specific concentration of acid or alkali in the liquid to hydrolyze the aluminum nitride, elemental aluminum and other aluminum compounds. After alkaline treatment, the liquid phase pH is greater than 14, mainly containing aluminates, chlorides, sulfides, sulfates, a small amount of fluoride and ammonia nitrogen. At present, acid or alkaline leaching methods are mostly used to treat secondary aluminum ash, so that aluminum nitride is efficiently hydrolyzed, and soluble salts are leached by acid or alkali, but there are still a large number of recyclable resources in its acidic or alkaline hydrolyzate. At present, the products obtained from the treatment of alkaline aluminum ash hydrolyzate are relatively single, and the resource utilization rate of aluminum ash hydrolyzate is low.

[0005] Moreover, in the process of recycling, the hydrolyzate is not treated sufficiently, which has a negative impact on the environment. In addition, although it is recycled, the amount of wastewater will increase when fresh water is added for recycling, and the concentration of high alkalinity will gradually increase when fresh water is not added. In the case of recycling, the final wastewater discharge may be more troublesome, accelerate the deterioration of equipment, and may also cause undesirable reactions with secondary aluminum ash. Summary of the invention

[0006] The first technical problem to be solved by the present invention is to provide a water treatment method after secondary aluminum ash hydrogen production, which can efficiently recover aluminum hydroxide and a variety of valuable salts. The obtained products are abundant, high in value, and environmentally friendly, and the use of new fresh water is reduced, and the high alkalinity concentration during circulation is reduced.

[0007] The second technical problem to be solved by the present invention is to provide a water treatment method after secondary aluminum ash hydrogen production, wherein the product or raw material can be recycled, the required raw materials are easily available, the equipment is simple, and the operation is simple.

[0008] In order to achieve the above technical effects, the present invention provides a water treatment method after secondary aluminum ash hydrogen production, comprising:

[0009] Collect the hydrolyzate after the secondary aluminum ash is used to produce hydrogen, and obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0010] Separating the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain a gas phase and a first-stage liquid phase;

[0011] dissolving carbon dioxide in the first liquid phase until a specified pH value is reached to obtain a second liquid phase;

[0012] dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0013] Adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0014] Evaporating the water in the fourth liquid phase of the inorganic phase;

[0015] The fourth-stage liquid phase of the organic phase is subjected to back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, the water in the inorganic liquid phase is evaporated, and the organic liquid phase is returned to the treatment of the third-stage liquid phase.

[0016] As an improvement of the above scheme, the temperature of the high-salt alkaline ammonia nitrogen hydrolyzate is 80-95°C, the alkalinity is 0.20-2.0 mol / L, the total salt content is 5-25%, and the ammonia nitrogen concentration is 200-2000 mg / L.

[0017] As an improvement of the above scheme, the high-salt alkali ammonia nitrogen hydrolyzate is subjected to ammonia nitrogen separation to obtain a gas phase and a first-level liquid phase, including: introducing air into the high-salt alkali ammonia nitrogen hydrolyzate for aeration to obtain a gas phase and a first-level liquid phase, and the gas phase is dissolved in water to obtain ammonia water.

[0018] As an improvement of the above scheme, the high-salinity alkali ammonia nitrogen hydrolyzate is subjected to ammonia nitrogen separation to obtain a gas phase and a first-stage liquid phase, which includes: introducing the high-salinity alkali ammonia nitrogen hydrolyzate into a reactor, setting the reactor speed to 40-150r / min, introducing air for aeration, and the air flow rate is 10-30m 3 / min, reaction time 0.5-3h, the obtained ammonia gas is passed into an absorption tower to obtain ammonia water.

[0019] As an improvement of the above scheme, dissolving carbon dioxide in the first-level liquid phase until a specified pH value is reached to obtain a second-level liquid phase includes: dissolving carbon dioxide in the first-level liquid phase until a specified pH value is reached, separating aluminum hydroxide from the first-level liquid phase, and obtaining aluminum hydroxide and a second-level liquid phase.

[0020] As an improvement of the above scheme, carbon dioxide is introduced into the first-stage liquid phase, the carbon dioxide flow rate is set to 1000-3000mL / min, the rotation speed is set to 30-150r / min, the reaction is stopped when the reaction pH drops from 12-14 to 7-8, and the slurry is separated into solid and liquid to obtain aluminum hydroxide and the second-stage liquid phase.

[0021] As an improvement of the above scheme, dissolving carbon dioxide in the second-level liquid phase until a specified pH value is reached to obtain a third-level liquid phase includes: dissolving carbon dioxide in the second-level liquid phase until a specified pH value is reached, subjecting the second-level liquid phase to sodium bicarbonate separation to obtain sodium bicarbonate and a third-level liquid phase.

[0022] As an improvement of the above scheme, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1000-3000mL / min, and the rotation speed is set to 40-150r / min. The reaction is stopped when the reaction pH drops from 7-8 to 5-6, and the slurry is separated into solid and liquid to obtain sodium bicarbonate and the third-stage liquid phase.

[0023] As an improvement of the above scheme, an extraction solvent is added to the third liquid phase and carbon dioxide is dissolved until a specified pH value is reached, and a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase are obtained after extraction and separation, comprising:

[0024] An extraction solvent is added to the third liquid phase and carbon dioxide is dissolved until a specified pH value is reached, chlorine is extracted and separated, and then a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase are obtained.

[0025] As an improvement of the above scheme, the third liquid phase is transferred to a reactor, carbon dioxide is introduced into the reactor, and an extraction solvent is added at the same time. The volume ratio of the organic phase:inorganic phase is set to (1-2):(2-3), and the solubility of carbon dioxide is set to 0.05-0.08 mol / L. The reaction is stopped when the reaction pH drops from 5-6 to 3-4. After extraction and separation, the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained.

[0026] The extraction solvent comprises an extractant and a diluent, wherein the extractant is one or more of alkyl primary amine, secondary amine, trioctyl tertiary amine, trioctyl methyl quaternary ammonium salt; the diluent is one or more of kerosene, tributyl phosphate, n-pentanol, n-hexanol, n-octanol, isooctyl alcohol;

[0027] The flow rate of the carbon dioxide is 1000-3000 mL / min;

[0028] The rotation speed of the reactor is set to 40-150 r / min, the reaction temperature is 20-25° C., and the reaction pressure is 1-3 Mpa.

[0029] As an improvement of the above scheme, the fourth liquid phase of the inorganic phase is subjected to MVR separation to evaporate the water to obtain sodium chloride and sodium sulfate.

[0030] As an improvement of the above scheme, the water in the fourth liquid phase of the inorganic phase is evaporated, comprising:

[0031] The fourth-level liquid phase of the inorganic phase is discharged from the bottom of the reactor and heated to 90-100° C., and then pumped into the MVR evaporator, and the compressor is started, and sodium sulfate and mother liquor are produced when sodium sulfate is supersaturated;

[0032] When the sodium sulfate concentration of the mother liquor is reduced to 3-7% and the temperature is reduced to 45-55°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation.

[0033] As an improvement of the above scheme, the fourth-level liquid phase of the organic phase is subjected to back-extraction separation to obtain an inorganic liquid phase and an organic liquid phase, the water in the inorganic liquid phase is evaporated, and the organic liquid phase is returned to the treatment of the third-level liquid phase, including: adding ammonia water to the fourth-level liquid phase of the organic phase for back-extraction separation to obtain an inorganic liquid phase and an organic liquid phase, wherein the water in the inorganic liquid phase is evaporated to obtain ammonium chloride; and the organic liquid phase is returned to the treatment of the third-level liquid phase.

[0034] As an improvement of the above scheme, ammonia water is added to the fourth liquid phase of the organic phase for back extraction separation, and the volume ratio of organic phase: inorganic phase is set to (1-2): (0.5-1), and the rotation speed is 40-150r / min.

[0035] The implementation of the present invention has the following beneficial effects:

[0036] 1. The present invention provides a treatment method using secondary aluminum ash alkaline hydrolyzate as raw water, which can recover aluminum hydroxide and further separate the impure salts to obtain high-value salts such as sodium bicarbonate, sodium chloride, sodium sulfate and ammonium chloride. The obtained products are rich, high in purity and high in value. The problem of single product and low added value impure salts produced by the existing aluminum ash alkaline hydrolyzate water treatment technology is solved.

[0037] 2. The products or raw materials of the treatment method of the present invention can be recycled, which is environmentally friendly and energy-saving. Moreover, the required raw materials are easily available, the operation is simple, and the equipment is simple.

[0038] 3. The present invention can reduce the usage of new fresh water, lower the high alkalinity concentration during circulation, achieve harmless treatment of secondary aluminum ash, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the water treatment method after secondary aluminum ash hydrogen production of the present invention;

[0040] Figure 2 This is a process flow chart for resource recycling of high-salinity alkaline ammonia nitrogen hydrolyzate. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] The present invention provides a method for treating water after secondary aluminum ash hydrogen production, such as Figure 1 and Figure 2 As shown, including:

[0043] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0044] The hydrolyzate after the secondary aluminum ash hydrogen production is collected and placed in a bottom porous ceramic aeration reactor for subsequent treatment.

[0045] Preferably, the high-salinity alkaline ammonia nitrogen hydrolyzate has a temperature of 80-95° C., an alkalinity of 0.20-2.0 mol / L, a total salt content of 5-25%, and an ammonia nitrogen concentration of 200-2000 mg / L.

[0046] More preferably, the temperature of the high-salinity alkaline ammonia nitrogen hydrolyzate is 85-90° C., the alkalinity is 0.25-1.5 mol / L, the total salt content is 10-20%, and the ammonia nitrogen concentration is 200-2000 mg / L.

[0047] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain a gas phase and a first-stage liquid phase;

[0048] Preferably, the high-salinity alkaline ammonia nitrogen hydrolyzate is aerated by passing air to obtain a gas phase and a first-stage liquid phase, and the gas phase is dissolved in water to obtain ammonia water.

[0049] More preferably, the high-salinity alkaline ammonia nitrogen hydrolyzate is introduced into a reactor, the speed of the reactor is set to 40-150r / min, and air is introduced for aeration, with an air flow rate of 10-30m 3 / min, reaction time 0.5-3h, the obtained ammonia gas is passed into an absorption tower to obtain ammonia water.

[0050] The present invention uses air aeration to drive away ammonia in the liquid phase, break the liquid phase buffer system, and prepare for subsequent pH adjustment. Moreover, the obtained ammonia is used in the subsequent stripping process to achieve the purpose of resource recycling. Furthermore, air aeration is used to oxidize pollutants such as reducing sulfide or thiosulfate in the liquid phase into sulfate at the same time, thereby increasing the purity of the subsequent sulfate.

[0051] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0052] Preferably, carbon dioxide is dissolved in the first-stage liquid phase until a specified pH value is reached, and the first-stage liquid phase is subjected to aluminum hydroxide separation to obtain aluminum hydroxide and a second-stage liquid phase.

[0053] More preferably, carbon dioxide is introduced into the first-stage liquid phase, the carbon dioxide flow rate is set to 1000-3000 mL / min, the rotation speed is set to 30-150 r / min, the reaction is stopped when the reaction pH drops from 12-14 to 7-8, the slurry is separated into solid and liquid to obtain aluminum hydroxide and the second-stage liquid phase.

[0054] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0055] Preferably, carbon dioxide is dissolved in the second-stage liquid phase until a specified pH value is reached, and the second-stage liquid phase is subjected to sodium bicarbonate separation to obtain sodium bicarbonate and a third-stage liquid phase.

[0056] More preferably, the second liquid phase is transferred to a reactor, carbon dioxide is introduced into the reactor, the carbon dioxide flow rate is set to 1000-3000 mL / min, the rotation speed is set to 40-150 r / min, the reaction is stopped when the reaction pH drops from 7-8 to 5-6, and the slurry is separated into solid and liquid to obtain sodium bicarbonate and the third liquid phase.

[0057] This step can achieve the following goals by adjusting the pH with carbon dioxide: first, aluminate can be precipitated into aluminum hydroxide; second, the amount of treated water does not need to be increased; and third, the alkali production principle can be used to produce high-valent salt sodium bicarbonate in a high-salt alkali system.

[0058] Aluminum hydroxide can be washed with water with a small amount of sodium bicarbonate crystals attached to it. The resulting sodium bicarbonate washing solution can be added with subsequent sodium chloride to saturate the solution and precipitate sodium bicarbonate crystals, thereby achieving the effect of resource recycling.

[0059] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0060] Preferably, an extraction solvent is added to the third liquid phase and carbon dioxide is dissolved until a specified pH value is reached, chlorine is extracted and separated, and then a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase are obtained.

[0061] Further preferably, the third liquid phase is transferred to a reaction kettle, carbon dioxide is introduced into the kettle, and an extraction solvent is added at the same time, the volume ratio of organic phase:inorganic phase is set to (1-2):(2-3), the solubility of carbon dioxide is set to 0.05-0.08 mol / L, the reaction pH is reduced from 5-6 to 3-4 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0062] More preferably, the third liquid phase is transferred to a reactor, and carbon dioxide is introduced into the reactor at a flow rate of 1000-3000 mL / min. An extraction solvent is added at the same time, and the volume ratio of the organic phase:inorganic phase is set to (1-2):(2-3), so that the solubility of carbon dioxide is 0.06-0.07 mol / L. The speed of the reactor is set to 40-150 r / min, the reaction temperature is 20-25°C, and the reaction pressure is 1-3 Mpa. The reaction is stopped when the reaction pH drops from 5-5.5 to 3-3.5, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0063] More preferably, the third liquid phase is transferred to a reactor, and carbon dioxide is introduced into the reactor at a flow rate of 1000-2000 mL / min. An extraction solvent is added at the same time, and the volume ratio of the organic phase:inorganic phase is set to 1:2, so that the solubility of carbon dioxide is 0.06-0.07 mol / L. The speed of the reactor is set to 40-150 r / min, the reaction temperature is 20-25°C, and the reaction pressure is 1-3 MPa. The reaction is stopped when the reaction pH drops from 5 to about 3, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0064] The extraction solvent comprises an extractant and a diluent, wherein the extractant is preferably one or more of alkyl primary amines, secondary amines, trioctyl tertiary amines, and trioctyl methyl quaternary ammonium salts, but is not limited thereto; the diluent is preferably one or more of kerosene, tributyl phosphate, n-pentanol, n-hexanol, n-octanol, and isooctyl alcohol, but is not limited thereto.

[0065] It should be noted that the extraction solvent of the present invention can be selected according to actual needs.

[0066] In this step, carbon dioxide is introduced and an extraction solvent is added for extraction and separation, so that chlorine can be extracted and separated efficiently. The extraction principle of chloride ions is as follows:

[0067]

[0068] Among them, R3N is the extractant, H + Provided by pressurized carbon dioxide, Cl － Provided by chloride ions in the liquid phase.

[0069] The present invention continues to use pressurized carbon dioxide plus extraction method to extract chlorine, so as to obtain ammonium chloride. The obtained ammonium chloride has high purity, and the extractant can be recycled after back extraction.

[0070] S106, evaporating the water in the fourth liquid phase of the inorganic phase.

[0071] Preferably, the fourth liquid phase of the inorganic phase is subjected to MVR separation to evaporate water to obtain sodium chloride and sodium sulfate.

[0072] Further preferably, the fourth-stage liquid phase of the inorganic phase is discharged from the bottom of the reactor and heated to 90-100° C., and then pumped into the MVR evaporator, and the compressor is started to produce sodium sulfate and mother liquor when the sodium sulfate is supersaturated;

[0073] When the sodium sulfate concentration of the mother liquor is reduced to 3-7% and the temperature is reduced to 45-55°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation.

[0074] More preferably, step S106 includes:

[0075] The fourth-level liquid phase of the inorganic phase is discharged from the bottom of the reactor and heated to 90-100°C, then pumped into the MVR evaporator, and the compressor is started. When the sodium sulfate is supersaturated, sodium sulfate and mother liquor are produced;

[0076] When the sodium sulfate concentration of the mother liquor is reduced to 4-6% and the temperature is reduced to 50-55°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation.

[0077] In this step, high-quality sodium chloride and sodium sulfate can be obtained through MVR separation, with high yield and high purity.

[0078] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0079] Preferably, aqueous ammonia is added to the fourth liquid phase of the organic phase for back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, wherein the water in the inorganic liquid phase is evaporated to obtain ammonium chloride; and the organic liquid phase is returned to the treatment of the third liquid phase.

[0080] Further preferably, when adding ammonia water to the fourth liquid phase of the organic phase for back extraction separation, the volume ratio of organic phase: inorganic phase is set to (1-2): (0.5-1), and the rotation speed is 40-150 r / min.

[0081] More preferably, ammonia water is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to 1:0.5, and the rotation speed is set to 40-150r / min for back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, wherein the fourth liquid phase of the organic phase is reused in the treatment of the third liquid phase in step S105 to evaporate the water in the inorganic liquid phase to obtain ammonium chloride.

[0082] It should be noted that the ammonia water added here may be the ammonia water obtained in step S102.

[0083] After the third-level liquid phase extraction and separation, the fourth-level liquid phase of the organic phase and the fourth-level liquid phase of the inorganic phase are obtained. The fourth-level liquid phase of the inorganic phase contains a small amount of sulfate and chloride. The present invention realizes zero wastewater discharge through MVR evaporation, and the fourth-level liquid phase of the organic phase is added with ammonia water for back extraction and separation to obtain ammonium chloride.

[0084] In summary, the present invention solves the problem of single product and low added value impurity salts produced by the existing aluminum ash alkaline hydrolyzate water treatment technology, and can further separate the impurity salts into high-value salts such as sodium bicarbonate, sodium chloride, sodium sulfate and ammonium chloride. Moreover, its products or raw materials can be recycled and reused, reducing the use of new fresh water and reducing the high alkalinity concentration during circulation.

[0085] The present invention is further described below with specific embodiments

[0086] Example 1 (30m 3 / d water volume treated)

[0087] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0088] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.6 mol / L, the aluminum ion concentration is 15 g / L, the total salinity is 12%, the chloride ion concentration is 27.7 g / L, the ammonia nitrogen concentration is 2000 mg / L, and the sulfide and thiosulfate concentrations are 1.98 g / L and 13.5 g / L.

[0089] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0090] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The speed of the reactor is set at 40r / min, and air is introduced for aeration. The air flow rate is 10 3 / min, reaction time 1h.

[0091] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0092] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1000mL / min, the rotation speed was set to 40r / min, the reaction was stopped when the reaction pH dropped from 14 to about 7, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0093] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0094] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1200mL / min, and the rotation speed is set to 40r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0095] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0096] Among them, the third liquid phase is transferred to the reactor, carbon dioxide is introduced into the reactor, the rotation speed is set to 40r / min, the flow rate of carbon dioxide is 1100mL / min, and the extraction solvent is added at the same time, the volume ratio of organic phase: inorganic phase is set to 1:2, the reaction temperature of the reactor is 20°C, the reaction pressure is 1.85Mpa, the solubility of carbon dioxide is set to 0.07mol / L, and the reaction pH is reduced from 6 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0097] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0098] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration.

[0099] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0100] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.5, the rotation speed is set to 40r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0101] Example 1 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0102]

[0103] Example 2 (30m 3 / d water volume treated)

[0104] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0105] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.55 mol / L, the aluminum ion concentration is 16 g / L, the total salinity is 13%, the chloride ion concentration is 28 g / L, the ammonia nitrogen concentration is 1900 mg / L, and the sulfide and thiosulfate concentrations are 1.88 g / L and 12 g / L.

[0106] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0107] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The reactor speed is set to 50r / min, and air is introduced for aeration. The air flow rate is 12m 3 / min, reaction time 1.5h.

[0108] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0109] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1200mL / min, the rotation speed was set to 30r / min, the reaction was stopped when the reaction pH dropped from 14 to about 7, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0110] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0111] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1300mL / min, and the rotation speed is set to 55r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0112] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0113] Among them, the third liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The rotation speed is set to 50r / min, the flow rate of carbon dioxide is 1450L / min, and the extraction solvent is added at the same time. The volume ratio of organic phase: inorganic phase is set to 1:2.2. The reaction temperature of the reactor is 21°C, the reaction pressure is 1.8Mpa, and the solubility of carbon dioxide is 0.065mol / L. The reaction pH is reduced from 5 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0114] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0115] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration;

[0116] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0117] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.45, the rotation speed is set to 35r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0118] Example 2 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0119]

[0120] Example 3 (30m 3 / d water volume treated)

[0121] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0122] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.57 mol / L, the aluminum ion concentration is 13 g / L, the total salinity is 16%, the chloride ion concentration is 25 g / L, the ammonia nitrogen concentration is 1888 mg / L, and the sulfide and thiosulfate concentrations are 1.7 g / L and 11 g / L.

[0123] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0124] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The reactor speed is set to 46r / min, and air is introduced for aeration. The air flow rate is 13m 3 / min, reaction time 1.3h.

[0125] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0126] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1314 mL / min, the rotation speed was set to 38 r / min, the reaction pH was stopped when it dropped from 14 to about 7, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0127] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0128] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1500mL / min, and the rotation speed is set to 45r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0129] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0130] Among them, the third liquid phase is transferred to the reactor, carbon dioxide is introduced into the reactor, the rotation speed is set to 54r / min, the flow rate of carbon dioxide is 1520mL / min, and the extraction solvent is added at the same time, and the volume ratio of organic phase: inorganic phase is set to 1:2.3. The reaction temperature of the reactor is 23°C, the reaction pressure is 1.77Mpa, and the solubility of carbon dioxide is 0.06mol / L. The reaction pH is reduced from 6 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0131] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0132] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration;

[0133] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0134] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.43, the rotation speed is set to 48r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0135] Example 3 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0136]

[0137] Example 4 (30m 3 / d water volume treated)

[0138] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0139] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.59 mol / L, the aluminum ion concentration is 15 g / L, the total salinity is 18%, the chloride ion concentration is 29 g / L, the ammonia nitrogen concentration is 1650 mg / L, and the sulfide and thiosulfate concentrations are 1.5 g / L and 16 g / L.

[0140] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0141] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The reactor speed is set to 48r / min, and air is introduced for aeration. The air flow rate is 15m 3 / min, reaction time 1.5h.

[0142] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0143] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1517mL / min, the rotation speed was set to 44r / min, the reaction pH was stopped when it dropped from 14 to about 7.2, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0144] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0145] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1750mL / min, and the rotation speed is set to 56r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0146] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0147] Among them, the third liquid phase is transferred to the reactor, carbon dioxide is introduced into the reactor, the rotation speed is set to 60r / min, the flow rate of carbon dioxide is 1780mL / min, and the extraction solvent is added at the same time, and the volume ratio of organic phase: inorganic phase is set to 1:2.11. The reaction temperature of the reactor is 25°C, the reaction pressure is 1.8Mpa, and the solubility of carbon dioxide is 0.07mol / L. The reaction pH is reduced from 5 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0148] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0149] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration;

[0150] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0151] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.49, the rotation speed is set to 50r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0152] Example 4 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0153]

[0154] Example 5 (30m 3 / d water volume treated)

[0155] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0156] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.46 mol / L, the aluminum ion concentration is 13.3 g / L, the total salinity is 16%, the chloride ion concentration is 23 g / L, the ammonia nitrogen concentration is 1764 mg / L, and the sulfide and thiosulfate concentrations are 1.3 g / L and 14 g / L.

[0157] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0158] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The reactor speed is set to 67r / min, and air is introduced for aeration. The air flow rate is 19m 3 / min, reaction time 1h.

[0159] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0160] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1866mL / min, the rotation speed was set to 58r / min, the reaction pH was stopped when it dropped from 14 to about 7, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0161] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0162] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1487mL / min, and the rotation speed is set to 65r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0163] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0164] Among them, the third liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The rotation speed is set to 66r / min, the flow rate of carbon dioxide is 1974mL / min, and the extraction solvent is added at the same time. The volume ratio of organic phase: inorganic phase is set to 1:2.14. The reaction temperature of the reactor is 24°C, the reaction pressure is 1.78Mpa, and the solubility of carbon dioxide is set to 0.07mol / L. The reaction pH is reduced from 6 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0165] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0166] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration;

[0167] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0168] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.501, the rotation speed is set to 50r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0169] Example 5 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0170]

[0171] Example 6 (30m 3 / d water volume treated)

[0172] S101, collecting the hydrolyzate after the secondary aluminum ash hydrogen production to obtain a high-salinity alkaline ammonia nitrogen hydrolyzate;

[0173] Among them, the hydroxide concentration of the high-salinity alkaline ammonia nitrogen hydrolyzate is 0.61 mol / L, the aluminum ion concentration is 14.3 g / L, the total salinity is 14%, the chloride ion concentration is 22 g / L, the ammonia nitrogen concentration is 1774 mg / L, and the sulfide and thiosulfate concentrations are 1.4 g / L and 12 g / L.

[0174] S102, separating ammonia nitrogen from the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain gaseous ammonia and a first-stage liquid phase, and dissolving the gaseous ammonia in water to obtain ammonia water;

[0175] The high-salinity alkaline ammonia nitrogen hydrolyzate is separated from the ammonia nitrogen in the reactor. The reactor speed is set to 68r / min, and air is introduced for aeration. The air flow rate is 20m 3 / min, reaction time 1.06h.

[0176] S103, dissolving carbon dioxide in the first-stage liquid phase until a specified pH value is reached to obtain a second-stage liquid phase;

[0177] Among them, carbon dioxide was introduced, the carbon dioxide flow rate was set to 1466mL / min, the rotation speed was set to 42r / min, the reaction pH was stopped when it dropped from 14 to about 7, and the slurry was transferred to a belt filter press for solid-liquid separation to obtain aluminum hydroxide and a second liquid phase.

[0178] S104, dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase;

[0179] Among them, the second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1743mL / min, and the rotation speed is set to 68r / min. The reaction is stopped when the reaction pH drops from 7 to about 6. The slurry is transferred to a plate and frame filter press for solid-liquid separation to obtain sodium bicarbonate and the third-stage liquid phase.

[0180] S105, adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation;

[0181] Among them, the third liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The rotation speed is set to 67r / min, the flow rate of carbon dioxide is 1687mL / min, and the extraction solvent is added at the same time. The volume ratio of organic phase: inorganic phase is set to 1:2.15. The reaction temperature of the reactor is 24°C, the reaction pressure is 1.78Mpa, and the solubility of carbon dioxide is 0.081mol / L. The reaction pH is reduced from 5 to about 3 to stop the reaction, and the fourth liquid phase of the organic phase and the fourth liquid phase of the inorganic phase are obtained after extraction and separation.

[0182] S106, evaporating the water in the fourth liquid phase of the inorganic phase;

[0183] Among them, the solution is discharged from the bottom of the reactor, heated to 100°C, and then pumped into the MVR crystallization evaporator, the compressor is started, and sodium sulfate and mother liquor are produced when the sodium sulfate concentration of the mother liquor is reduced to 5%, the temperature is reduced to 50°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation concentration;

[0184] S107, performing back extraction separation on the fourth-level liquid phase of the organic phase to obtain an inorganic liquid phase and an organic liquid phase, evaporating the water in the inorganic liquid phase, and returning the organic liquid phase to the treatment of the third-level liquid phase.

[0185] Among them, after the inorganic is separated in step S105, part of the ammonia water in step S102 is added to the fourth liquid phase of the organic phase, the volume ratio of the organic phase: the inorganic phase is set to about 1:0.504, the rotation speed is set to 66r / min, and the back extraction separation is performed to obtain the fourth liquid phase of the organic phase and reuse it in step S105, and the fourth liquid phase of the inorganic phase is concentrated and evaporated to obtain ammonium chloride.

[0186] Example 6 30m 3 The hydrolyzate of / d was treated and the obtained product was tested, and the results are as follows:

[0187]

[0188] In summary, the embodiment of the present invention can separate aluminum hydroxide, sodium bicarbonate, sodium chloride, sodium sulfate, ammonium chloride and saturated ammonia water, and the obtained products are abundant and have high yield; and the obtained aluminum hydroxide, sodium bicarbonate, sodium chloride, sodium sulfate and ammonium chloride have a purity of more than 90% and are of high value.

[0189] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for treating water after secondary aluminum ash hydrogen production, characterized in that: include: Collect the hydrolyzate after the secondary aluminum ash is used to produce hydrogen, and obtain a high-salinity, alkaline, ammonia-nitrogen hydrolyzate; Separating the high-salinity alkaline ammonia nitrogen hydrolyzate to obtain a gas phase and a first-stage liquid phase; dissolving carbon dioxide in the first liquid phase until a specified pH value is reached to obtain a second liquid phase; dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase; Adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, and obtaining a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase after extraction and separation; Evaporating the water in the fourth liquid phase of the inorganic phase; The fourth-stage liquid phase of the organic phase is subjected to back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, the water in the inorganic liquid phase is evaporated, and the organic liquid phase is returned to the treatment of the third-stage liquid phase.

2. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: The high-salinity alkaline ammonia nitrogen hydrolyzate is subjected to ammonia nitrogen separation to obtain a gas phase and a first-stage liquid phase, including: The high-salinity alkaline ammonia nitrogen hydrolyzate is introduced into the reactor, the speed of the reactor is set to 40-150r / min, and air is introduced for aeration, with an air flow rate of 10-30m 3 / min, reaction time 0.5-3h, the obtained ammonia gas is passed into an absorption tower to obtain ammonia water.

3. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: Dissolving carbon dioxide in the first liquid phase until a specified pH value is reached to obtain a second liquid phase comprising: Carbon dioxide is dissolved in the first-stage liquid phase until a specified pH value is reached, and aluminum hydroxide is separated from the first-stage liquid phase to obtain aluminum hydroxide and a second-stage liquid phase.

4. The water treatment method after secondary aluminum ash hydrogen production according to claim 3, characterized in that: Carbon dioxide is introduced into the first-stage liquid phase, and the carbon dioxide flow rate is set to 1000-3000 mL / min and the rotation speed is set to 30-150 r / min. The reaction is stopped when the reaction pH drops from 12-14 to 7-8, and the slurry is separated into solid and liquid to obtain aluminum hydroxide and the second-stage liquid phase.

5. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: Dissolving carbon dioxide in the second-stage liquid phase until a specified pH value is reached to obtain a third-stage liquid phase, comprising: Carbon dioxide is dissolved in the second-stage liquid phase until a specified pH value is reached, and the second-stage liquid phase is subjected to sodium bicarbonate separation to obtain sodium bicarbonate and a third-stage liquid phase.

6. The water treatment method after secondary aluminum ash hydrogen production according to claim 5, characterized in that: The second-stage liquid phase is transferred to the reactor, and carbon dioxide is introduced into the reactor. The carbon dioxide flow rate is set to 1000-3000mL / min, and the rotation speed is set to 40-150r / min. When the reaction pH drops from 7-8 to 5-6, the reaction is stopped, and the slurry is separated into solid and liquid to obtain sodium bicarbonate and the third-stage liquid phase.

7. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: Adding an extraction solvent to the third liquid phase and dissolving carbon dioxide until a specified pH value is reached, extracting and separating to obtain a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase, comprising: An extraction solvent is added to the third liquid phase and carbon dioxide is dissolved until a specified pH value is reached, chlorine is extracted and separated, and then a fourth liquid phase of an organic phase and a fourth liquid phase of an inorganic phase are obtained.

8. The water treatment method after secondary aluminum ash hydrogen production according to claim 7, characterized in that: The third-level liquid phase is transferred to a reaction kettle, carbon dioxide is introduced into the kettle, and an extraction solvent is added at the same time, and the volume ratio of the organic phase: the inorganic phase is set to (1-2): (2-3), and the solubility of carbon dioxide is set to 0.05-0.08 mol / L. The reaction is stopped when the reaction pH drops from 5-6 to 3-4, and the fourth-level liquid phase of the organic phase and the fourth-level liquid phase of the inorganic phase are obtained after extraction and separation; The extraction solvent comprises an extractant and a diluent, wherein the extractant is one or more of alkyl primary amine, secondary amine, trioctyl tertiary amine, trioctyl methyl quaternary ammonium salt; the diluent is one or more of kerosene, tributyl phosphate, n-pentanol, n-hexanol, n-octanol, isooctyl alcohol; The flow rate of the carbon dioxide is 1000-3000 mL / min; The rotation speed of the reactor is set to 40-150 r / min, the reaction temperature is 20-25° C., and the reaction pressure is 1-3 Mpa.

9. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: Evaporating the water in the fourth liquid phase of the inorganic phase comprises: The fourth-level liquid phase of the inorganic phase is discharged from the bottom of the reactor and heated to 90-100° C., and then pumped into the MVR evaporator, and the compressor is started, and sodium sulfate and mother liquor are produced when sodium sulfate is supersaturated; When the sodium sulfate concentration of the mother liquor is reduced to 3-7% and the temperature is reduced to 45-55°C, the mother liquor is transported to the MVR evaporator, the compressor is turned on, and sodium chloride is obtained after supersaturation.

10. The water treatment method after secondary aluminum ash hydrogen production according to claim 1, characterized in that: The fourth-stage liquid phase of the organic phase is subjected to back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, the water in the inorganic liquid phase is evaporated, and the organic liquid phase is returned to the treatment of the third-stage liquid phase, comprising: Adding ammonia water to the fourth-stage liquid phase of the organic phase for back extraction separation to obtain an inorganic liquid phase and an organic liquid phase, wherein the water in the inorganic liquid phase is evaporated to obtain ammonium chloride; and the organic liquid phase is returned to the treatment of the third-stage liquid phase; Ammonia water is added to the fourth liquid phase of the organic phase for back extraction separation, and the volume ratio of the organic phase: the inorganic phase is set to (1-2): (0.5-1), and the rotation speed is 40-150r / min.

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