Method for resource utilization of denitration catalyst regeneration and activation impregnation waste liquid
Through the multi-step treatment of the denitrition catalyst re-living impregnation waste liquid, including solid-liquid separation, pH adjustment and extraction technology, the efficient recycling of vanadium elements and the preparation of high-purity products have been successfully achieved, and the loss of vanadium elements and water pollution have been solved. The problem is that the heavy metal content in the waste liquid is reduced.
Patent Information
- Application Number
- CN202411385045.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2024-12-27
AI Technical Summary
The prior art is difficult to effectively treat and resource the use of denitrification catalysts and reuse domestic impregnation waste liquid, resulting in huge loss of vanadium elements and the risk of water pollution.
Through solid-liquid separation, pH adjustment, calcium and magnesium salt reaction, acidification extraction agent extraction and ammonia water back-extraction treatment, vanadium element is selectively purified from the re-living impregnation waste liquid of the denitrification catalyst, and the vanadium is isolated and recovered. , prepare high-purity vanadium pentoxide or vanadium dioxide.
The preparation of high recovery rate (over 85%) and high purity (99% and above) products of vanadium element is achieved, reducing the content of heavy metals and harmful elements in the waste liquid and reducing the risk of water pollution.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of resource utilization of heavy metal waste liquid, and in particular to a method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid. Background Art
[0002] Selective catalytic reduction (SCR) denitrification technology is currently the most mature flue gas denitrification technology. As the core of SCR denitrification technology, SCR denitrification catalysts will be deactivated during use due to dust accumulation, blockage, wear, sintering, chemical poisoning, loss of active components, etc. The service life of denitrification catalysts is generally 24,000 hours, and most power plants have a replacement cycle of 3 years. Denitrification catalysts that have expired are called deactivated denitrification catalysts. For deactivated catalysts with complete size and intact structure, regeneration is given priority, that is, physical and chemical methods are used to remove impurities on the catalyst surface and in the pores, and the catalyst activity is restored by implanting active components. At present, catalyst regeneration technology is relatively mature. The activity of the regenerated catalyst can reach more than 95% of that of the new catalyst, and the chemical life is equivalent to that of the new catalyst, while the cost is less than half of the new catalyst, reflecting good economic and social benefits.
[0003] As the core of denitration catalyst regeneration technology, the regeneration activation impregnation solution uses ammonium metavanadate as the main formula, and a certain amount of co-solvents such as oxalic acid and sulfuric acid are added. During the impregnation process, elements such as Fe, K, Na, Mg, Al, Si, As, and P on the surface and matrix of the deactivated catalyst are also leached out and enriched in the activation impregnation solution. The activation impregnation solution will therefore lose its function of replenishing activity and become a "poison" instead, causing deep poisoning of the denitration catalyst. Therefore, during the catalyst regeneration process, the concentration of each element in the activation impregnation solution needs to be monitored and discharged regularly.
[0004] The composition of the discharged regeneration activation impregnation waste liquid is extremely complex, with characteristics such as low pH value, high salt content, high heavy metal content, and high COD. It is extremely difficult to treat and is the main environmental risk for deactivated denitrification catalyst regeneration companies. At present, chemical precipitation + adsorption filtration process is generally used to remove vanadium from wastewater. Among them, the chemical precipitation method generally adds lime to the wastewater and controls the pH value at around 11-13, so that the vanadium element in the wastewater forms an insoluble calcium vanadate precipitate, and removes heavy metal ions through solid-liquid separation. As a deep treatment method after secondary treatment, the adsorption method further removes trace residual heavy metals in the wastewater to ensure that the wastewater meets the discharge standards. The vanadium content in the regeneration activation impregnation waste liquid is usually above 1500 mg / L, and the risk of stable discharge that meets the standards is huge. In addition, the calcium vanadate precipitate formed needs to be disposed of as hazardous waste, which is difficult to achieve resource utilization, resulting in a huge loss of vanadium, a valuable metal. Summary of the invention
[0005] The purpose of the present invention is to overcome the problems existing in the prior art and provide a method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid, which can selectively purify and enrich valuable metal vanadium from waste liquid containing a variety of impurity ions, separate vanadium elements from other impurity elements, and realize the recycling of valuable metal vanadium, with a recovery rate of more than 85%, and the purity of the prepared vanadium product is as high as 99% or more; at the same time, the content of heavy metals and harmful elements in the discharged waste liquid is effectively reduced, thereby reducing the risk of water pollution.
[0006] In order to achieve the above object, the present invention provides a method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid, the method comprising the following steps: (1) performing solid-liquid separation on the denitration catalyst regeneration activation impregnation wastewater and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 8.5-10, adding calcium salt and / or magnesium salt to react, and obtaining an intermediate material; (3) Adjusting the pH value of the intermediate material to 12-14 for reaction, then performing solid-liquid separation and collecting filtrate B; (4) adjusting the pH value of the filtrate B to 3-6, then extracting with an acidified extractant, and collecting the organic phase and the first aqueous phase; (5) stripping the organic phase collected in step (4) with aqueous ammonia, collecting the second aqueous phase, and then evaporating, crystallizing and calcining; Wherein, in step (1), the denitration catalyst regeneration activation impregnation waste liquid contains iron, aluminum, silicon, arsenic, phosphorus, potassium, sodium, magnesium and vanadium; In step (4), the extractant contains kerosene, alkylamine, neutral organic phosphorus compound and optional high carbon alcohol.
[0007] Preferably, in step (1), the pH value of the denitration catalyst regeneration activation impregnation wastewater is 2-4.
[0008] Preferably, in step (2), the reaction conditions include: temperature of 50-80° C. and time of 0.5-1.5 h.
[0009] Preferably, in step (3), the reaction conditions include: temperature of 50-80° C. and time of 1-2 h.
[0010] Preferably, in step (4), the preparation process of the acidified extractant comprises: acidifying the extractant with an acidic aqueous solution.
[0011] Preferably, the acid in the acidic aqueous solution is selected from one or more of hydrochloric acid, sulfuric acid and nitric acid.
[0012] Preferably, in step (4), based on the total weight of the extractant, the content of kerosene is 50-85wt%, the content of alkylamine is 5-25wt%, the content of neutral organic phosphorus compound is 5-20wt%, and the content of higher alcohol is 0-10wt%.
[0013] Preferably, in step (4), the extraction conditions include: the volume ratio of the acidified extractant to the pH-adjusted filtrate B is 1-4:20, and the extraction time is 5-30 min.
[0014] Preferably, in step (5), the concentration of the ammonia water is 10wt%-30wt%.
[0015] Preferably, in step (5), the stripping conditions include: the volume ratio of the organic phase to aqueous ammonia is 1-3:1, and the stripping time is 5-30 min.
[0016] Preferably, in step (5), the calcination conditions include: temperature of 300-500° C. and time of 2-6 h.
[0017] The method of the present invention can selectively purify and enrich valuable metal vanadium from waste liquid containing multiple impurity ions, separate vanadium element and other impurity elements, and realize the recycling of valuable metal vanadium, with a recovery rate of more than 85%, and the purity of the prepared vanadium product is as high as 99% or more; at the same time, it can effectively reduce the content of heavy metals and harmful elements in the discharged waste liquid, reducing the risk of water pollution. DETAILED DESCRIPTION
[0018] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0019] The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.
[0020] The present invention provides a method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid, the method comprising the following steps: (1) performing solid-liquid separation on the denitration catalyst regeneration activation impregnation wastewater and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 8.5-10, adding calcium salt and / or magnesium salt to react, and obtaining an intermediate material; (3) Adjusting the pH value of the intermediate material to 12-14 for reaction, then performing solid-liquid separation and collecting filtrate B; (4) adjusting the pH value of the filtrate B to 3-6, then extracting with an acidified extractant, and collecting the organic phase and the first aqueous phase; (5) stripping the organic phase collected in step (4) with aqueous ammonia, collecting the second aqueous phase, and then evaporating, crystallizing and calcining; Wherein, in step (1), the denitration catalyst regeneration activation impregnation waste liquid contains iron, aluminum, silicon, arsenic, phosphorus, potassium, sodium, magnesium and vanadium; In step (4), the extractant contains kerosene, alkylamine, neutral organic phosphorus compound and optional high carbon alcohol.
[0021] In the present invention, the denitrification catalyst regeneration activation impregnation waste liquid refers to the waste liquid obtained after treating the deactivated denitrification catalyst with the regeneration activation impregnation liquid, and the denitrification catalyst regeneration activation impregnation waste liquid contains iron, aluminum, silicon, arsenic, phosphorus, potassium, sodium, magnesium and vanadium.
[0022] In the present invention, the "intermediate material" in step (2) is the reaction system obtained after "adjusting the pH value of the filtrate A to 8.5-10, adding calcium salt and / or magnesium salt to react".
[0023] The step (1) of the present invention can remove the suspended matter in the denitration catalyst regeneration activation impregnation wastewater; the step (2) adjusting the pH value of the filtrate A to 8.5-10, the added calcium salt and / or magnesium salt can precipitate aluminum, silicon, arsenic and phosphorus elements, and the iron element in the filtrate A will also generate iron hydroxide precipitation in the process; the step (3) adjusting the pH value of the intermediate material to 12-14 can make the magnesium element and calcium element in the filtrate form precipitation, and then perform solid-liquid separation, remove the precipitation generated in step (2) and step (3), and obtain a filtrate B containing potassium element, sodium element and vanadium element; the step (4) adjusting the pH value of the filtrate B to 3-6, so that the vanadium element is contained in the filtrate. The negatively charged polyvanadate exists in the form of a salt of polyvanadate and thus associates with the positively charged extractant after acidification and enters the organic phase, while the potassium and sodium elements remain in the aqueous phase, thereby achieving the separation of the vanadium element from the potassium and sodium elements, and obtaining an organic phase and a first aqueous phase; by adding ammonia water in step (5), the pH value of the system is increased, and the polyvanadate present in the organic phase of step (4) will dissociate and re-enter the aqueous phase to obtain a second aqueous phase, and at the same time, no new impurity elements will be introduced into the second aqueous phase, and then the second aqueous phase is collected, evaporated, crystallized and calcined. By controlling the gas atmosphere during the calcination process, vanadium pentoxide is obtained in an oxygen-rich atmosphere, and vanadium dioxide is obtained in an oxygen-deficient or reducing atmosphere.
[0024] In summary, the method described in the present invention can reduce the types and contents of heavy metals in waste liquid and reduce water pollution. At the same time, it can also recover the valuable metal vanadium to prepare high-purity vanadium pentoxide or vanadium dioxide to realize the resource utilization of vanadium element.
[0025] In a preferred embodiment, the pH value of the denitration catalyst regeneration activation impregnation wastewater is 2-4.
[0026] In the present invention, there is no special requirement for the substance for adjusting the pH value of the filtrate A to 8.5-10 in step (2), as long as the pH value of the filtrate A can be adjusted to 8.5-10; in a preferred embodiment, in order to avoid the introduction of new impurities, an alkaline substance whose cation is sodium ion or potassium ion is used, specifically, sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate.
[0027] In a preferred embodiment, in order to further improve the removal rate of aluminum, silicon, arsenic, phosphorus and iron elements, in step (2), the reaction conditions include: temperature of 50-80°C and time of 0.5-1.5h; preferably, temperature of 60-70°C and time of 0.5-1h.
[0028] In a specific embodiment, the calcium salt may be calcium nitrate or calcium chloride, and the magnesium salt may be magnesium sulfate, magnesium chloride or magnesium nitrate.
[0029] In a preferred embodiment, in order to further improve the removal rate of magnesium and calcium, in step (3), the reaction conditions include: temperature of 50-80°C and time of 1-2h; preferably, temperature of 60-70°C and time of 1-1.5h.
[0030] In the present invention, there is no special requirement for the substance for adjusting the pH value of the intermediate material to 12-14 in step (3), as long as the pH value of the intermediate material can be adjusted to 12-14; in a preferred embodiment, in order to avoid the introduction of new impurities, an alkaline substance whose cation is sodium ion or potassium ion is used, specifically, sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate.
[0031] In the present invention, there is no special requirement for the substance for adjusting the pH value of the filtrate B to 3-6 in step (4), as long as the pH value of the filtrate B can be adjusted to 3-6; in a preferred embodiment, an inorganic acid aqueous solution is used to adjust the pH value of the filtrate B to 3-6, and the inorganic acid is selected from sulfuric acid and / or hydrochloric acid.
[0032] In a preferred embodiment, in step (4), the preparation process of the acidified extractant includes: acidifying the extractant with an acidic aqueous solution.
[0033] In a preferred embodiment, the acid in the acidic aqueous solution is selected from one or more of hydrochloric acid, sulfuric acid and nitric acid.
[0034] In a specific implementation, the extractant is acidified with dilute sulfuric acid at a concentration of 0.1 mol / L for 10 minutes, the volume ratio of the extractant to the dilute sulfuric acid is 1:1, and then the mixture is allowed to stand for stratification, and the organic phase is collected.
[0035] In the present invention, in step (4), the pH value of the filtrate B is adjusted to 3-6, so that the vanadium element exists in the form of a negatively charged polyvanadate, and the acidification of the extractant can make the alkylamine contained in the extractant positively charged, and the negatively charged polyvanadate associates with the positively charged alkylamine and enters the organic phase, while the potassium element and the sodium element remain in the aqueous phase, thereby achieving the separation of the vanadium element from the potassium element and the sodium element, and obtaining the organic phase and the first aqueous phase.
[0036] In a preferred embodiment, in order to improve the association efficiency of the extractant with vanadium element and improve the extraction effect, in step (4), based on the total weight of the extractant, the content of kerosene is 50-85wt%, the content of alkylamine is 5-25wt%, the content of neutral organic phosphorus compound is 5-20wt%, and the content of high carbon alcohol is 0-10wt%; preferably, the content of kerosene is 60-75wt%, the content of alkylamine is 10-20wt%, the content of neutral organic phosphorus compound is 10-15wt%, and the content of high carbon alcohol is 2.5-7.5wt%.
[0037] In the present invention, the kerosene may be kerosene or sulfonated kerosene.
[0038] In a preferred embodiment, the alkylamine is one or more of N235 (trioctyldecyl tertiary amine), N1923 (N-(1-methylheptyl)-2-acetamide) and Alamine 308 (tri-n-octylamine); the neutral organophosphorus compound is one or more of TBP (tributyl phosphate), P507 (2-ethylhexyl mono-2-ethylhexyl phosphate) and D2EHPA (di-(2-ethylhexyl) phosphoric acid); and the high-carbon alcohol is one or more of sec-octanol, n-octanol and C1618 alcohol.
[0039] In the most preferred embodiment, the extractant is a mixture of sulphonated kerosene, N235, TBP and sec-octanol.
[0040] In a preferred embodiment, in order to further improve the extraction efficiency of the extractant for vanadium, in step (4), the extraction conditions include: the volume ratio of the acidified extractant to the pH-adjusted filtrate B is 1-4:20, and the time is 5-30 min; preferably, the volume ratio of the acidified extractant to the pH-adjusted filtrate B is 2-4:20, and the time is 10-25 min.
[0041] In a preferred embodiment, in order to improve the extraction efficiency of vanadium by aqueous ammonia in step (5), the concentration of aqueous ammonia is 10wt%-30wt%; preferably 12.5wt%-25wt%; specifically, the concentration of aqueous ammonia can be 12.5wt%, 15wt%, 17.5wt%, 20wt%, 22.5wt% or 25wt%.
[0042] In a preferred embodiment, in order to further improve the extraction efficiency of vanadium by aqueous ammonia, in step (5), the stripping conditions include: the volume ratio of the organic phase to aqueous ammonia is 1-3:1, and the time is 5-30 min; preferably, the volume ratio of the organic phase to aqueous ammonia is 1.5-2.5:1, and the time is 10-25 min.
[0043] In a preferred embodiment, in order to obtain high-purity vanadium pentoxide or vanadium dioxide, in step (5), the calcination conditions include: temperature of 300-500°C and time of 2-6h; preferably, temperature of 350-450°C and time of 3-5h.
[0044] In the present invention, in step (5), by adding ammonia water with a concentration of 10wt%-30wt%, the pH value of the system is increased without introducing new impurity elements, and the polyvanadate in the organic phase will dissociate to form monomeric vanadium salts. At the same time, the positively charged alkylamines will become electrically neutral as the pH value of the system increases. The monomeric vanadium salts cannot associate with the electrically neutral alkylamines in the organic phase, so the monomeric vanadium salts will enter the aqueous phase from the organic phase to obtain a second aqueous phase. At the same time, no new impurity elements will be introduced into the second aqueous phase. The second aqueous phase is then collected, evaporated, crystallized and calcined. By controlling the oxygen concentration during the calcination process, vanadium pentoxide is obtained in an atmosphere with an oxygen concentration of >6 volume %, and vanadium dioxide is obtained in an atmosphere with an oxygen concentration of <6 volume %.
[0045] The following examples further illustrate the method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid of the present invention. The examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.
[0046] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.
[0047] The element contents in the denitration catalyst regeneration activation impregnation waste liquid treated in the following examples and comparative examples are shown in Table 1; Table 1
[0048] Example 1 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 9.5 with sodium hydroxide, then adding a magnesium sulfate solution with a mass fraction of 25 wt% to react under stirring at a temperature of 65° C. for 0.5 h to obtain an intermediate material; (3) The pH value of the intermediate material was adjusted to 14 using sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B1 was collected; (4) The pH value of the filtrate B1 was adjusted to 3.5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate B1, the volume ratio of the acidified extractant to the pH-adjusted filtrate B1 was 4:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) was subjected to reverse extraction for 10 min with 12.5 wt % ammonia water, wherein the volume ratio of the organic phase to the ammonia water was 2:1. The second aqueous phase was collected and then evaporated and crystallized using an MVR evaporator. The phase was calcined for 4 h in an atmosphere with an oxygen concentration of 100 vol % at a calcination temperature of 400° C. to obtain vanadium pentoxide.
[0049] Example 2 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) The pH value of the filtrate A was adjusted to 8.5 using sodium hydroxide, and then a magnesium sulfate solution with a mass fraction of 25 wt% was added to react under stirring at a temperature of 65° C. for 0.5 h to obtain an intermediate material; (3) The pH value of the intermediate material was adjusted to 13 using sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B2 was collected; (4) The pH value of the filtrate B2 was adjusted to 5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate B2, the volume ratio of the acidified extractant to the pH-adjusted filtrate B2 was 4:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) was subjected to reverse extraction for 10 min with 12.5 wt % ammonia water, wherein the volume ratio of the organic phase to the ammonia water was 2:1. The second aqueous phase was collected and then evaporated and crystallized using an MVR evaporator. The phase was calcined for 4 h in an oxygen-free atmosphere at a temperature of 400° C. to obtain vanadium dioxide.
[0050] Example 3 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) The pH value of the filtrate A was adjusted to 9 with sodium hydroxide, and then a 25 wt% calcium chloride solution was added to react under stirring at a temperature of 65° C. for 0.5 h to obtain an intermediate material; (3) The pH value of the intermediate material was adjusted to 12 using sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B3 was collected; (4) The pH value of the filtrate B3 was adjusted to 4.5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate B3, the volume ratio of the acidified extractant to the pH-adjusted filtrate B3 was 4:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) is subjected to reverse extraction for 10 min with 12.5 wt % ammonia water, wherein the volume ratio of the organic phase to the ammonia water is 2:1. The second aqueous phase is collected and then evaporated and crystallized using an MVR evaporator. The phase is calcined for 4 h in an atmosphere with an oxygen concentration of 20 vol % at a calcination temperature of 400° C. to obtain vanadium pentoxide.
[0051] Example 4 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 9.5 with sodium hydroxide, then adding a magnesium sulfate solution with a mass fraction of 25 wt% to react under stirring at a temperature of 65° C. for 0.5 h to obtain an intermediate material; (3) The pH value of the intermediate material was adjusted to 14 using sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B4 was collected; (4) The pH value of the filtrate B4 was adjusted to 3.5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate B4, the volume ratio of the acidified extractant to the pH-adjusted filtrate B4 was 0.5:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) is subjected to reverse extraction with 12.5 wt % ammonia water for 10 min, wherein the volume ratio of the organic phase to the ammonia water is 2:1. The second aqueous phase is collected and then evaporated and crystallized using an MVR evaporator. The phase is calcined for 4 h in an atmosphere of 100 vol % oxygen concentration at a calcination temperature of 400° C. to obtain vanadium pentoxide.
[0052] Example 5 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 9.5 with sodium hydroxide, then adding a magnesium sulfate solution with a mass fraction of 25 wt% to react under stirring at a temperature of 65° C. for 0.5 h to obtain an intermediate material; (3) The pH value of the intermediate material was adjusted to 14 using sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B6 was collected; (4) The pH value of the filtrate B5 was adjusted to 3.5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate B5, the volume ratio of the acidified extractant to the pH-adjusted filtrate B5 was 0.5:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) was subjected to reverse extraction for 10 min with 12.5 wt % ammonia water, wherein the volume ratio of the organic phase to the ammonia water was 4:1. The second aqueous phase was collected and then evaporated and crystallized using an MVR evaporator. The phase was calcined for 4 h in an atmosphere with an oxygen concentration of 100 vol % at a calcination temperature of 400° C. to obtain vanadium pentoxide.
[0053] Comparative Example 1 The method of Example 1 is followed, except that in step (2), the pH value of the filtrate in step (1) is adjusted to 11.
[0054] Comparative Example 2 The method of Example 1 is followed, except that in step (3), the pH value of the intermediate material in step (2) is adjusted to 11.
[0055] Comparative Example 3 The method of Example 1 is followed, except that in step (4), the pH value of the filtrate in step (3) is adjusted to 10.
[0056] Comparative Example 4 (1) filtering the denitration catalyst regeneration activation impregnation waste liquid and collecting the filtrate A; (2) The pH value of the filtrate A was adjusted to 14 with sodium hydroxide and the reaction was carried out under stirring at a temperature of 65°C for 1 hour. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid, and the filtrate B6 was collected; (3) adjusting the pH value of the filtrate B6 to 9.5 with 50% by mass sulfuric acid, then adding 25% by mass magnesium sulfate solution to react under stirring at a temperature of 65°C for 0.5 h. After cooling, a vacuum belt dehydrator was used to separate the solid and liquid to obtain a filtrate C1; (4) The pH value of the filtrate C1 was adjusted to 3.5 with 50% sulfuric acid by mass, and then the extractant (67.5wt% sulfonated kerosene, 15wt% N235, 12.5wt% TBP and 5wt% octanol) was acidified with 0.1mol / L dilute sulfuric acid for 10min, the volume ratio of dilute sulfuric acid to extractant was 1:1, and then the aqueous phase was removed by standing and stratification, and the acidified extractant was used to extract the pH-adjusted filtrate C1, the volume ratio of the acidified extractant to the pH-adjusted filtrate C1 was 4:20, and the extraction was performed for 10min. After standing and stratification, the organic phase and the first aqueous phase were collected; (5) The organic phase obtained in step (4) was subjected to reverse extraction for 10 min with 12.5 wt % ammonia water, wherein the volume ratio of the organic phase to the ammonia water was 2:1. The second aqueous phase was collected and then evaporated and crystallized using an MVR evaporator. The phase was calcined for 4 h in an atmosphere with an oxygen concentration of 100 vol % at a calcination temperature of 400° C. to obtain vanadium pentoxide.
[0057] Test Case (1) The element types and contents of the first aqueous phase collected in the embodiment and the comparative example were detected. The unit of the content of each element was mg / L. The test results are shown in Table 2. Table 2
[0058] “-” indicates not detected (2) The recovery rate of vanadium element in the embodiment and the comparative example was calculated, and the purity of the vanadium products prepared in the embodiment and the comparative example was detected. The calculation results are shown in Table 3; Table 3
[0059] It can be seen from the results in Table 1 and Table 2 that the method described in the present invention is used to treat the denitration catalyst regeneration activation impregnation waste liquid, which can selectively purify and enrich the valuable metal vanadium from the waste liquid containing a variety of impurity ions, separate the vanadium element from other impurity elements, and realize the recycling of the valuable metal vanadium. The recovery rate is as high as more than 85%, and the purity of the prepared vanadium product is as high as 99% or more; at the same time, the content of heavy metals and harmful elements in the discharged waste liquid is effectively reduced, reducing the risk of water pollution.
[0060] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.
Claims
1. A method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid, characterized in that: The method comprises the following steps: (1) performing solid-liquid separation on the denitration catalyst regeneration activation impregnation wastewater and collecting the filtrate A; (2) adjusting the pH value of the filtrate A to 8.5-10, adding calcium salt and / or magnesium salt to react, and obtaining an intermediate material; (3) Adjusting the pH value of the intermediate material to 12-14 for reaction, then performing solid-liquid separation and collecting filtrate B; (4) adjusting the pH value of the filtrate B to 3-6, then extracting with an acidified extractant, and collecting the organic phase and the first aqueous phase; (5) stripping the organic phase collected in step (4) with aqueous ammonia, collecting the second aqueous phase, and then evaporating, crystallizing and calcining; Wherein, in step (1), the denitration catalyst regeneration activation impregnation waste liquid contains iron, aluminum, silicon, arsenic, phosphorus, potassium, sodium, magnesium and vanadium; In step (4), the extractant contains kerosene, alkylamine, neutral organic phosphorus compound and optional high carbon alcohol.
2. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1, characterized in that: In step (1), the pH value of the denitration catalyst regeneration activation impregnation wastewater is 2-4.
3. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1 or 2, characterized in that: In step (2), the reaction conditions include: temperature of 50-80°C and time of 0.5-1.5h.
4. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1, characterized in that: In step (3), the reaction conditions include: temperature of 50-80°C and time of 1-2h.
5. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1, characterized in that: In step (4), the preparation process of the acidified extractant includes: acidifying the extractant with an acidic aqueous solution; Preferably, the acid in the acidic aqueous solution is selected from one or more of hydrochloric acid, sulfuric acid and nitric acid.
6. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1 or 5, characterized in that: In step (4), based on the total weight of the extractant, the content of kerosene is 50-85wt%, the content of alkylamine is 5-25wt%, the content of neutral organic phosphorus compound is 5-20wt%, and the content of higher alcohol is 0-10wt%.
7. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 6, characterized in that: In step (4), the extraction conditions include: the volume ratio of the acidified extractant to the pH-adjusted filtrate B is 1-4:20, and the extraction time is 5-30 minutes.
8. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1, characterized in that: In step (5), the concentration of the ammonia water is 10wt%-30wt%.
9. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 1 or 8, characterized in that: In step (5), the stripping conditions include: the volume ratio of the organic phase to the ammonia water is 1-3:1, and the stripping time is 5-30 min.
10. The method for resource utilization of denitration catalyst regeneration activation impregnation waste liquid according to claim 9, characterized in that: In step (5), the calcination conditions include: temperature of 300-500°C and time of 2-6h.