Method for separating vanadium and tungsten from waste SCR (Selective Catalytic Reduction) denitration catalyst lixivium through ion exchange resin

Abstract

The invention relates to the technical field of vanadium and tungsten separation, and discloses a method for separating vanadium and tungsten from a waste SCR denitration catalyst leachate through ion exchange resin, which comprises the following steps: washing and alkaline leaching a waste SCR denitration catalyst to generate a solution containing vanadium and tungsten, adsorbing the solution containing vanadium and tungsten through modified polystyrene ion exchange resin, and then carrying out desorption reaction, vanadium precipitation reaction and tungsten precipitation reaction to obtain vanadium and tungsten. And filtering and separating to realize separation and purification of vanadium and tungsten. The modified polystyrene ion exchange resin contains a large number of sodium sulfonate and Schiff base structures, has strong coordination chelation and adsorption performance on vanadium and tungsten ions, can efficiently adsorb the vanadium and tungsten ions in a solution containing vanadium and tungsten into the resin, and can efficiently adsorb the vanadium and tungsten ions in the solution containing vanadium and tungsten through the processes of optimization analysis, vanadium precipitation, tungsten precipitation reaction and the like. The obtained calcium vanadate and calcium tungstate have the advantages of high yield and high purity.

Description

Technical Field

[0001] The invention relates to the technical field of vanadium-tungsten separation, and in particular to a method for separating vanadium-tungsten from waste SCR denitration catalyst leaching liquid by using ion exchange resin. Background Art

[0002] Vanadium and tungsten are both rare metals, widely used in industry and military fields. With the reduction of high-quality mineral resources and increasingly stringent environmental protection policies, the recovery of vanadium and tungsten from secondary resources has important research and application value. Waste SCR catalyst is one of the important secondary resources of vanadium and tungsten. SCR denitrification catalyst is widely used in industrial processes to reduce the emission of nitrogen oxides. These catalysts usually contain active components such as vanadium (V) and tungsten (W), of which vanadium and tungsten are mainly V 2 O 5 , WO 3 In the process of treating spent SCR catalysts, the recovery of vanadium and tungsten has important economic value and environmental significance. However, due to their similar existence in the leachate, traditional separation methods are often inefficient or costly.

[0003] How to effectively separate and recycle vanadium and tungsten in spent SCR catalysts, explore new, more efficient, environmentally friendly and economical vanadium-tungsten separation technologies to improve production efficiency and product quality, while reducing costs and environmental impact, and recycling resources has important resource value and environmental significance.

[0004] CN118600216A discloses a method for recovering tungsten, molybdenum, vanadium and titanium from waste SCR denitration catalyst, wherein vanadium is separated by acid leaching, and then a tungsten-molybdenum mixed solution and titanium-rich slag are separated by sodium roasting. The titanium-rich slag is used to produce TiO 2 The product is then separated from the tungsten-molybdenum mixed solution by a molybdenum selective separation agent, evaporated, crystallized, and roasted to obtain MoO 3 The product is then extracted by organic extraction to recover WO 3 Although it is possible to separate, purify and recycle tungsten, molybdenum, vanadium and titanium from the waste SCR denitration catalyst, both sodium roasting and extraction are required. The overall process is long, the equipment requirements are high, the energy consumption is high, and a large amount of wastewater needs to be treated at the same time, resulting in high environmental protection treatment costs.

[0005] CN106756054A discloses a method for separating and recovering titanium, tungsten and vanadium from waste SCR denitration catalysts, and the main products obtained are rutile titanium dioxide, tungsten trioxide and vanadium pentoxide, and byproducts are silicon dioxide and calcium carbonate. Although different titanium, tungsten and vanadium products are separated, this method cannot process waste catalysts with complex raw material components, the types of materials to be processed are limited, and the process route is complex and the operation requirements are high, and the process wastewater cannot be treated.

[0006] Although these methods have made some progress in laboratory-scale research in recent years, they still face some challenges in actual industrial applications, including improving separation efficiency, reducing costs, reducing environmental pollution, and achieving the feasibility of large-scale applications.

[0007] Polystyrene ion exchange resin has a mesh and porous structure, contains active functional groups such as sulfonic acid and carboxyl, has strong adsorption performance and high separation effect, and is widely used in the separation, purification and enrichment of metal elements. The development of high-performance polystyrene ion exchange resin is a research hotspot. Summary of the invention

[0008] The technical problem solved by the present invention is: to provide a method for separating vanadium and tungsten by using modified polystyrene ion exchange resin and waste SCR denitration catalyst leachate through ion exchange resin, which has the advantages of simple process conditions and easy operation, high recovery rate of vanadium and tungsten, good purification effect, low energy consumption, high resource utilization rate of complete medium circulation, and broad application prospects.

[0009] The technical solution provided by the present invention is: a method for separating vanadium and tungsten from waste SCR denitration catalyst leachate through ion exchange resin:

[0010] (1) Acid solution is added to the vanadium-containing tungsten solution, and after adjusting the pH value of the solution, the vanadium-containing tungsten solution is flowed into an ion exchange device filled with modified polystyrene ion exchange resin after precise filtration for adsorption until adsorption is saturated.

[0011] (2) Take out the modified polystyrene ion exchange resin, place it in an alkaline solution for analytical reaction, and completely dissolve vanadium and tungsten in the analytical solution.

[0012] (3) adding a vanadium precipitation agent to the analytical solution, stirring to carry out vanadium precipitation reaction, filtering and separating to obtain calcium vanadate and vanadium precipitation liquid.

[0013] (4) Adjust the pH of the vanadium precipitation liquid, add a tungsten precipitation agent, stir to carry out tungsten precipitation reaction, filter and separate, and obtain the circulating mother liquor and calcium tungstate. The tungsten precipitation liquid can be returned to step (2) and the operation is repeated for separation.

[0014] Preferably, the vanadium-tungsten solution in (1) is produced by washing and alkali leaching of the waste SCR denitration catalyst.

[0015] Preferably, V in the vanadium-containing tungsten solution 2 O 5 The concentration is 1-5g / L, WO 3 The concentration is 5-10g / L; acid is added to adjust the solution pH to 1-4, and the acid is any one or a combination of sulfuric acid, hydrochloric acid or nitric acid.

[0016] Preferably, when the vanadium-containing tungsten solution in (1) flows into the ion exchange device, the temperature of the solution is 20-50° C. and the flow rate is 1-4 BV / h.

[0017] Preferably, the alkali solution in (2) is any one or a combination of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water. The alkalinity of the alkali solution is 10-15%.

[0018] Preferably, during the decomposition reaction, the flow rate of the alkali solution is 0.5-1 BV / h, the decomposition volume is 0.5-3.5 BV, and the temperature of the alkali solution is 20-50°C.

[0019] Preferably, the endpoint of complete dissolution of vanadium and tungsten in (2) can be determined by the color of the resin, and the resin is acidified and regenerated for reuse after the analysis.

[0020] Preferably, in (3), the alkalinity of the analytical solution is controlled to be 5-10%; V in the vanadium precipitation agent and the vanadium-containing tungsten solution 2 O 5 The molar ratio is (1.2-1.5):1.

[0021] Preferably, the filtration separation method in (3) is plate and frame filtration or vacuum filtration.

[0022] Preferably, the vanadium precipitation agent is any one or a combination of calcium oxide, calcium hydroxide or calcium sulfate. The temperature during the vanadium precipitation reaction is 60-80°C and the time is 1-2 hours.

[0023] Preferably, in (4), the pH of the solution after vanadium precipitation is adjusted to 9-12, and the tungsten precipitation agent and WO in the solution are 3 The molar ratio is (1.2-1.5):1; the tungsten precipitant is any one or combination of calcium carbonate, calcium phosphate, and calcium chloride. By adjusting the reaction pH, it is possible to avoid incomplete adsorption and analysis due to too low or too high pH, ​​which affects the conversion rate, and effectively ensure the regeneration and reuse of the resin.

[0024] Preferably, the temperature of the tungsten precipitation reaction is 80-100° C. and the time is 1-2 hours.

[0025] Preferably, the preparation method of the modified polystyrene ion exchange resin is:

[0026] S1. Add 4-chloromethylbenzaldehyde and o-aminophenol in a molar ratio of 1:(1-1.05) to ethanol, stir and react at 30-40°C for 4-6h, heat to evaporate, cool in an ice-water bath and recrystallize to obtain 2-[(4-(chloromethyl)benzylidene)amino]phenol. The reaction formula is:

[0027]

[0028] S2. Add 100 parts by weight of chloromethyl polystyrene resin to toluene, stir and swell, then add 200-350 parts by weight of N,N-bis(2-hydroxyethyl)ethylenediamine, heat to 70-80°C, stir and react for 18-30 hours, then add 240-440 parts by weight of potassium carbonate and 270-490 parts by weight of 2-[(4-(chloromethyl)benzylidene)amino]phenol, stir and react for 18-24 hours, filter, wash with water, ethanol, and dry in turn to obtain modified polystyrene resin.

[0029] S3, add 100 parts by weight of modified polystyrene resin to 1,4-dioxane, stir and swell, then add 180-330 parts by weight of 1,4-butanesultone, an aqueous solution containing 54-95 parts by weight of sodium hydroxide, heat to 65-75°C, stir and react for 12-18h, filter, wash with water, ethanol, and dry in turn to obtain modified polystyrene ion exchange resin. The reaction formula is:

[0030]

[0031] The technical effect of the present invention is: the present invention sequentially utilizes chloromethyl polystyrene resin to react with N,N-bis(2-hydroxyethyl)ethylenediamine, 2-[(4-(chloromethyl)benzylidene)amino]phenol, and 1,4-butanesulfonic acid lactone to obtain a modified polystyrene ion exchange resin containing a large amount of sodium sulfonate and Schiff base structure. Sodium sulfonate and Schiff base structure have strong coordination chelation and adsorption properties for vanadium and tungsten ions, and can efficiently adsorb vanadium and tungsten ions in vanadium-containing tungsten solution into the resin, and through the optimization of analysis, vanadium precipitation and tungsten precipitation reaction processes, the obtained calcium vanadate and calcium tungstate have the advantages of high yield and high purity.

[0032] The method for separating vanadium and tungsten from waste SCR leachate by using ion exchange resin provided by the present invention has simple process requirements for separating vanadium and tungsten. The effect of efficiently separating tungsten and vanadium can be achieved by simple adsorption, analysis and chemical precipitation methods, and there is no requirement for the content of impurity elements.

[0033] The method for separating vanadium and tungsten from waste SCR leachate by using ion exchange resin provided by the present invention can improve the adsorption efficiency of tungsten and vanadium, has a short reaction process, low energy consumption loss, low medium full circulation operation cost, is clean and environmentally friendly, is more beneficial to environmental protection, and can realize industrial production.

[0034] The method for separating vanadium and tungsten from waste SCR leachate by ion exchange resin provided by the present invention can be adsorbed by specific ion exchange resin, and the liquid after adsorption can directly meet the emission standard, directly solve the wastewater problem, have a large adsorption saturation capacity, will not generate secondary pollution, and effectively recover valuable metals. DETAILED DESCRIPTION

[0035] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0036] In the embodiment of the present invention, the vanadium-containing tungsten solution is produced by washing and alkali leaching of the waste SCR denitration catalyst.

[0037] Example 1

[0038] (1) Add 30 mmol of 4-chloromethylbenzaldehyde and 30 mmol of o-aminophenol to 80 mL of ethanol, stir and react at 30° C. for 5 h, heat to evaporate, cool in an ice-water bath and recrystallize to obtain 2-[(4-(chloromethyl)benzylidene)amino]phenol.

[0039] (2) Add 10 g of chloromethyl polystyrene resin to 100 mL of toluene, stir and swell, then add 20 g of N,N-bis(2-hydroxyethyl)ethylenediamine, heat to 75°C, stir and react for 18 h, then add 24 g of potassium carbonate and 27 g of 2-[(4-(chloromethyl)benzylidene)amino]phenol, stir and react for 18 h, filter, wash with water, ethanol, and dry in turn to obtain a modified polystyrene resin.

[0040] (3) Add 10 g of modified polystyrene resin to 100 mL of 1,4-dioxane, stir until swelling, then add 18 g of 1,4-butanesulfonate and 15 mL of an aqueous solution containing 5.4 g of sodium hydroxide, heat to 75° C., stir for 12 h, filter, wash with water, ethanol, and dry in sequence to obtain a modified polystyrene ion exchange resin.

[0041] (4) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 2.5g / L, WO 3 Sulfuric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 7.5g / L), the pH value of the solution is adjusted to 2, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 30°C and the flow rate is 3BV / h for adsorption until adsorption is saturated.

[0042] (5) The modified polystyrene ion exchange resin was taken out and placed in ammonia water with an alkalinity of 12% for analytical reaction at a temperature of 30° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0043] (6) Adjust the alkalinity of the analytical solution to 7%, add calcium oxide as a vanadium precipitator, and the calcium oxide reacts with the V in the solution. 2 O 5 The molar ratio of vanadium is 1.5:1, and the vanadium precipitation reaction is carried out at 80°C with stirring for 2 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0044] (7) Adjust the pH of the solution after vanadium precipitation to 10, add calcium phosphate as a tungsten precipitation agent, and the amount of calcium phosphate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.5:1, and the tungsten precipitation reaction is carried out at 92°C with stirring for 2 hours. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0045] Example 2

[0046] (1) Add 30 mmol of 4-chloromethylbenzaldehyde and 31.5 mmol of o-aminophenol to 100 mL of ethanol, stir and react at 40° C. for 4 h, heat to evaporate, cool in an ice-water bath to recrystallize, and obtain 2-[(4-(chloromethyl)benzylidene)amino]phenol.

[0047] (2) Add 10 g of chloromethyl polystyrene resin to 120 mL of toluene, stir and swell, then add 28 g of N,N-bis(2-hydroxyethyl)ethylenediamine, heat to 80°C, stir and react for 18 h, then add 35 g of potassium carbonate and 40 g of 2-[(4-(chloromethyl)benzylidene)amino]phenol, stir and react for 24 h, filter, wash with water, ethanol, and dry in turn to obtain a modified polystyrene resin.

[0048] (3) Add 10 g of modified polystyrene resin to 120 mL of 1,4-dioxane, stir and swell, then add 26 g of 1,4-butanesulfonate and 25 mL of an aqueous solution containing 7.5 g of sodium hydroxide, heat to 65° C., stir and react for 18 h, filter, wash with water, ethanol, and dry in sequence to obtain a modified polystyrene ion exchange resin.

[0049] (4) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 1g / L, WO 3 A nitric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 5g / L), the pH of the solution is adjusted to 1, and the vanadium-containing tungsten solution is precisely filtered to flow into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 20°C and the flow rate is 1BV / h. Adsorption is carried out until adsorption is saturated.

[0050] (5) The modified polystyrene ion exchange resin was taken out and placed in a potassium hydroxide aqueous solution with a basicity of 11% for analytical reaction at a temperature of 20° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0051] (6) Adjust the alkalinity of the analytical solution to 5%, add calcium sulfate, a vanadium precipitant, and the calcium sulfate and V in the solution 2 O 5 The molar ratio of vanadium is 1.2:1, and the vanadium precipitation reaction is carried out at 70°C with stirring for 1 hour. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0052] (7) Adjust the pH of the solution after vanadium precipitation to 11, add calcium chloride, a tungsten precipitation agent, and the calcium chloride reacts with WO in the solution. 3 The molar ratio of tungsten to calcium tungstate is 1.2:1, and the tungsten precipitation reaction is carried out at 95°C with stirring for 1 hour. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0053] Example 3

[0054] (1) Add 30 mmol of 4-chloromethylbenzaldehyde and 30 mmol of o-aminophenol to 80 mL of ethanol, stir and react at 30° C. for 6 h, heat to evaporate, cool in an ice-water bath and recrystallize to obtain 2-[(4-(chloromethyl)benzylidene)amino]phenol.

[0055] (2) Add 10 g of chloromethyl polystyrene resin to 150 mL of toluene, stir and swell, then add 35 g of N,N-bis(2-hydroxyethyl)ethylenediamine, heat to 70°C, stir and react for 30 h, then add 44 g of potassium carbonate and 49 g of 2-[(4-(chloromethyl)benzylidene)amino]phenol, stir and react for 24 h, filter, wash with water, ethanol, and dry in turn to obtain a modified polystyrene resin.

[0056] (3) Add 10 g of modified polystyrene resin to 120 mL of 1,4-dioxane, stir and swell, then add 33 g of 1,4-butanesulfonate and 30 mL of an aqueous solution containing 9.5 g of sodium hydroxide, heat to 70° C., stir and react for 18 h, filter, wash with water, ethanol, and dry in sequence to obtain a modified polystyrene ion exchange resin.

[0057] (4) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 2g / L, WO 3 Sulfuric acid solution is added into the vanadium-containing tungsten solution (with a concentration of 6g / L), the pH value of the solution is adjusted to 2, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 30°C and the flow rate is 2BV / h for adsorption until adsorption is saturated.

[0058] (5) The modified polystyrene ion exchange resin was taken out and placed in a sodium hydroxide solution with an alkalinity of 13% for analytical reaction at a temperature of 30° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0059] (6) Adjust the alkalinity of the analytical solution to 9%, add calcium oxide as a vanadium precipitator, and the calcium oxide and V in the solution 2 O 5 The molar ratio of vanadium is 1.3:1, and the vanadium precipitation reaction is carried out at 80°C with stirring for 1.2 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0060] (7) Adjust the pH of the solution after vanadium precipitation to 12, add calcium carbonate as a tungsten precipitation agent, and the amount of calcium carbonate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.3:1, and the tungsten precipitation reaction is carried out by stirring at 100°C for 1.2 hours, and filtered to separate to obtain the circulating mother liquor and high-purity calcium tungstate.

[0061] Example 4

[0062] (1) Prepare modified polystyrene ion exchange resin according to the method of Example 2.

[0063] (2) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 3g / L, WO 3 The concentration of vanadium tungsten is 7g / L) and hydrochloric acid solution is added to adjust the pH of the solution to 3. The vanadium tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium tungsten solution is 35°C and the flow rate is 3BV / h. Adsorption is carried out until adsorption is saturated.

[0064] (3) The modified polystyrene ion exchange resin was taken out and placed in ammonia water with an alkalinity of 11% for analytical reaction at a temperature of 35° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0065] (4) Adjust the alkalinity of the analytical solution to 7%, add vanadium precipitant calcium hydroxide, and the calcium hydroxide and V in the solution 2 O 5 The molar ratio of vanadium is 1.4:1, and the vanadium precipitation reaction is carried out at 77°C with stirring for 1.7 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0066] (5) Adjust the pH of the solution after vanadium precipitation to 12, add calcium sulfate as a tungsten precipitation agent, and the amount of calcium sulfate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.4:1, and the tungsten precipitation reaction is carried out by stirring at 98°C for 1.7 hours, and filtered to separate to obtain the circulating mother liquor and high-purity calcium tungstate.

[0067] Example 5

[0068] (1) Prepare modified polystyrene ion exchange resin according to the method of Example 3.

[0069] (2) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 4g / L, WO 3 A nitric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 9g / L), the pH value of the solution is adjusted to 4, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 45°C and the flow rate is 4BV / h for adsorption until adsorption is saturated.

[0070] (3) The modified polystyrene ion exchange resin is taken out and placed in a potassium hydroxide aqueous solution with a basicity of 14% for analytical reaction at a temperature of 45° C. until vanadium and tungsten are completely dissolved in the analytical solution.

[0071] (4) Adjust the alkalinity of the analytical solution to 8%, add calcium sulfate as a vanadium precipitant, and the calcium sulfate and V in the solution 2 O 5 The molar ratio of vanadium is 1.4:1, and the vanadium precipitation reaction is carried out at 75°C with stirring for 1.8 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0072] (5) Adjust the pH of the solution after vanadium precipitation to 11, add calcium phosphate as a tungsten precipitation agent, and the amount of calcium phosphate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.4:1, and the tungsten precipitation reaction is carried out at 90°C with stirring for 2 hours. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0073] Example 6

[0074] (1) Prepare modified polystyrene ion exchange resin according to the method of Example 3.

[0075] (2) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 4.4g / L, WO 3 Sulfuric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 6.6 g / L), the pH value of the solution is adjusted to 3.4, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 44°C and the flow rate is 3.4 BV / h for adsorption until adsorption is saturated.

[0076] (3) The modified polystyrene ion exchange resin was taken out and placed in a sodium hydroxide aqueous solution with a basicity of 13% for analytical reaction at a temperature of 38° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0077] (4) Adjust the alkalinity of the analytical solution to 5%, add calcium oxide as a vanadium precipitator, and the calcium oxide and V in the solution 2 O5 The molar ratio of vanadium is 1.3:1, and the vanadium precipitation reaction is carried out at 79°C with stirring for 1.9 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0078] (5) Adjust the pH of the solution after vanadium precipitation to 9, add calcium carbonate as a tungsten precipitation agent, and the amount of calcium carbonate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.3:1, and the tungsten precipitation reaction is carried out by stirring at 99°C for 1.9 hours, and filtered to separate to obtain the circulating mother liquor and high-purity calcium tungstate.

[0079] Example 7

[0080] (1) Prepare modified polystyrene ion exchange resin according to the method of Example 2.

[0081] (2) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 3.2g / L, WO 3 Sulfuric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 7.2 g / L), the pH value of the solution is adjusted to 2.1, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 23°C and the flow rate is 2.1 BV / h for adsorption until adsorption is saturated.

[0082] (3) The modified polystyrene ion exchange resin was taken out and placed in a sodium hydroxide aqueous solution with a basicity of 10% for analytical reaction at a temperature of 41° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0083] (4) Adjust the alkalinity of the analytical solution to 6%, add calcium oxide as a vanadium precipitator, and the calcium oxide reacts with the V in the solution. 2 O 5 The molar ratio of vanadium is 1.4:1, and the vanadium precipitation reaction is carried out at 70°C with stirring for 1.4 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0084] (5) Adjust the pH of the solution after vanadium precipitation to 10, add calcium carbonate as a tungsten precipitation agent, and the amount of calcium carbonate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.3:1, and the tungsten precipitation reaction is carried out by stirring at 98.5°C for 1.1h, and filtered to separate to obtain the circulating mother liquor and high-purity calcium tungstate.

[0085] Comparative Example 1

[0086] The main difference between this comparative example and Example 1 is that the modified polystyrene resin is used instead of the modified polystyrene ion exchange resin.

[0087] (1) A modified polystyrene resin was prepared according to the method of Example 1.

[0088] (2) Add vanadium-containing tungsten solution (V 2O 5 The concentration is 2.5g / L, WO 3 Sulfuric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 7.5g / L), the pH value of the solution is adjusted to 2, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene resin. The temperature of the vanadium-containing tungsten solution is 30°C and the flow rate is 3BV / h for adsorption until adsorption is saturated.

[0089] (3) The modified polystyrene resin was taken out and placed in ammonia water with an alkalinity of 12% for analytical reaction at a temperature of 30° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0090] (4) Adjust the alkalinity of the analytical solution to 7%, add calcium oxide as a vanadium precipitator, and the calcium oxide reacts with the V in the solution. 2 O 5 The molar ratio of vanadium is 1.5:1, and the vanadium precipitation reaction is carried out at 80°C with stirring for 2 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0091] (5) Adjust the pH of the solution after vanadium precipitation to 10, add calcium phosphate as tungsten precipitation agent, and the amount of calcium phosphate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.5:1, and the tungsten precipitation reaction is carried out at 92°C with stirring for 2 hours. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0092] Comparative Example 2

[0093] The main difference between this comparative example and Example 1 is that 2-[(4-(chloromethyl)benzylidene)amino]phenol is not added when preparing the modified polystyrene resin.

[0094] (1) Add 10 g of chloromethyl polystyrene resin to 100 mL of toluene, stir until swelling, then add 20 g of N,N-bis(2-hydroxyethyl)ethylenediamine, heat to 75° C., stir and react for 18 h, filter, wash with water, ethanol, and dry in sequence to obtain a modified polystyrene resin.

[0095] (2) Add 10 g of modified polystyrene resin to 100 mL of 1,4-dioxane, stir until swelling, then add 18 g of 1,4-butanesulfonate and 15 mL of an aqueous solution containing 5.4 g of sodium hydroxide, heat to 75° C., stir for 12 h, filter, wash with water, ethanol, and dry in sequence to obtain a modified polystyrene ion exchange resin.

[0096] (3) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 2.5g / L, WO 3Sulfuric acid solution is added to the vanadium-containing tungsten solution (with a concentration of 7.5g / L), the pH value of the solution is adjusted to 2, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with modified polystyrene ion exchange resin. The temperature of the vanadium-containing tungsten solution is 30°C and the flow rate is 3BV / h for adsorption until adsorption is saturated.

[0097] (4) The modified polystyrene ion exchange resin was taken out and placed in ammonia water with an alkalinity of 12% for analytical reaction at a temperature of 30° C. until vanadium and tungsten were completely dissolved in the analytical solution.

[0098] (5) Adjust the alkalinity of the analytical solution to 7%, add calcium oxide as a vanadium precipitator, and the calcium oxide reacts with the V in the solution. 2 O 5 The molar ratio of vanadium is 1.5:1, and the vanadium precipitation reaction is carried out at 80°C with stirring for 2 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0099] (6) Adjust the pH of the solution after vanadium precipitation to 10, add calcium phosphate as a tungsten precipitation agent, and the amount of calcium phosphate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.5:1, and the tungsten precipitation reaction is carried out at 92°C with stirring for 2 hours. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0100] Comparative Example 3

[0101] The main difference between this comparative example and Example 1 is that a commercially available sulfonic acid cation exchange resin is used instead of the modified polystyrene ion exchange resin.

[0102] (1) Add vanadium-containing tungsten solution (V 2 O 5 The concentration is 2.5g / L, WO 3 Sulfuric acid solution is added into the vanadium-containing tungsten solution (with a concentration of 7.5g / L), the pH value of the solution is adjusted to 2, and the vanadium-containing tungsten solution is precisely filtered and flows into an ion exchange device filled with sulfonic acid cation exchange resin (brand is Sany Resin 001X10). The temperature of the vanadium-containing tungsten solution is 30°C and the flow rate is 3BV / h, and adsorption is carried out until adsorption is saturated.

[0103] (2) The sulfonic acid cation exchange resin was taken out and placed in ammonia water with a basicity of 12% for decomposition reaction at a temperature of 30° C. until vanadium and tungsten were completely dissolved in the decomposition solution.

[0104] (3) Adjust the alkalinity of the analytical solution to 7%, add calcium oxide as a vanadium precipitator, and the calcium oxide reacts with the V in the solution. 2 O 5 The molar ratio of vanadium is 1.5:1, and the vanadium precipitation reaction is carried out at 80°C with stirring for 2 hours. The reaction is filtered and separated to obtain high-purity calcium vanadate and vanadium precipitation liquid.

[0105] (4) Adjust the pH of the solution after vanadium precipitation to 10, add calcium phosphate as tungsten precipitation agent, and the amount of calcium phosphate added should be proportional to the amount of WO in the solution. 3 The molar ratio is 1.5:1, and the tungsten precipitation reaction is carried out at 92°C with stirring for 2 hours. The circulating mother liquor and high-purity calcium tungstate are obtained by filtration and separation.

[0106] Comparative Example 4

[0107] The difference between this comparative example and Example 3 is that a tungsten precipitation agent is first added to precipitate tungsten, and then a vanadium precipitation agent is added to precipitate vanadium. The remaining steps are the same as those in Example 3.

[0108] Comparative Example 5

[0109] The difference between this comparative example and Example 5 is that in (4), the alkalinity of the analytical solution is not adjusted, and the vanadium precipitation agent calcium sulfate is directly added to carry out the vanadium precipitation reaction. The remaining steps are the same as those in Example 5.

[0110] Comparative Example 6

[0111] The difference between this comparative example and Example 2 is that in (7), the pH of the solution after vanadium precipitation is adjusted, and the tungsten precipitation agent calcium chloride is directly added to carry out tungsten precipitation reaction, and the remaining steps are the same as Example 2.

[0112] The purity of the obtained calcium vanadate and calcium tungstate is tested by atomic absorption spectrometer.

[0113] Recovery rate = n / n 0 × 100%.n 0 V in vanadium-containing tungsten solution 2 O 5 The molar amount of calcium vanadate (CaV 2 O 6 )The molar amount actually recovered.

[0114] Calcium tungstate recovery rate = n / n 0 × 100%.n 0 WO in vanadium-containing tungsten solution 3 The molar amount of calcium tungstate (CaWO 4 )The molar amount actually recovered.

[0115] Table 1

[0116]

[0117]

[0118] After testing, Examples 1-7 used modified polystyrene ion exchange resin to adsorb and analyze the vanadium-containing tungsten solution, and achieved efficient separation, purification and enrichment of vanadium and tungsten through vanadium precipitation and tungsten precipitation reactions. This is because the modified polystyrene ion exchange resin contains a large number of sodium sulfonate groups and Schiff base structures, and has strong coordination, chelating and adsorption properties for vanadium and tungsten ions. The vanadium and tungsten ions in the vanadium-containing tungsten solution can be efficiently adsorbed into the resin, and by optimizing the analysis, vanadium precipitation and tungsten precipitation reactions, the obtained calcium vanadate and calcium tungstate have the advantages of high yield and high purity.

[0119] In comparative example 1, modified polystyrene resin is used to replace modified polystyrene ion exchange resin, which does not contain sulfonic acid groups. In comparative example 2, 2-[(4-(chloromethyl)benzylidene)amino]phenol is not added when preparing modified polystyrene resin, and the obtained modified polystyrene ion exchange resin does not contain Schiff base structure. In comparative example 3, commercially available sulfonic acid cation exchange resin is used to replace modified polystyrene ion exchange resin, which does not contain Schiff base structure. The three have strong coordination chelation and weak adsorption performance for vanadium and tungsten ions, and it is difficult to completely and effectively adsorb vanadium and tungsten ions into the resin matrix, resulting in a low yield of calcium vanadate and calcium tungstate.

[0120] In comparative example 4, a tungsten precipitation agent was first added to precipitate tungsten, and then a vanadium precipitation agent was added to precipitate vanadium. In comparative example 5, the alkalinity of the analytical solution was not adjusted. In comparative example 6, the pH of the solution after vanadium precipitation was not adjusted. The separation process of the three was not optimized and improved, and the purity of the obtained calcium vanadate and calcium tungstate was low, and the yield was low.

[0121] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for separating vanadium and tungsten from waste SCR denitration catalyst leachate by ion exchange resin, characterized in that: The method comprises the following steps: (1) adding acid solution to the vanadium-containing tungsten solution, adjusting the pH value of the solution, and then precisely filtering the vanadium-containing tungsten solution and flowing it into an ion exchange device filled with modified polystyrene ion exchange resin for adsorption; (2) taking out the modified polystyrene ion exchange resin, placing it in an alkaline solution for analytical reaction, and dissolving vanadium and tungsten into the analytical solution; (3) adding a vanadium precipitation agent to the analytical solution, stirring to carry out vanadium precipitation reaction, filtering and separating to obtain calcium vanadate and a vanadium precipitation solution; (4) Adjust the pH of the vanadium precipitation solution, add a tungsten precipitation agent, stir to carry out tungsten precipitation reaction, filter and separate, obtain the circulating mother liquor and calcium tungstate, return the tungsten precipitation solution to step (2), and repeat the operation for separation.

2. The method for separating vanadium and tungsten from the waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: The vanadium-containing tungsten solution in (1) is produced by washing and alkali leaching of waste SCR denitration catalyst; the concentration of V2O5 in the vanadium-containing tungsten solution is 1-5 g / L, and the concentration of WO3 is 5-10 g / L; acid solution is added to adjust the solution pH to 1-4, and the acid solution is any one or a combination of sulfuric acid, hydrochloric acid or nitric acid.

3. The method for separating vanadium and tungsten from the waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: When the vanadium-containing tungsten solution in (1) flows into the ion exchange device, the temperature of the solution is 20-50° C. and the flow rate is 1-4 BV / h.

4. The method for separating vanadium and tungsten from the waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: The alkali solution in (2) is any one or a combination of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia water; the alkalinity of the alkali solution is 10-15%, the flow rate of the alkali solution during the decomposition reaction is 0.5-1BV / h, the decomposition volume is 0.5-3.5BV, and the alkali solution temperature is 20-50°C.

5. The method for separating vanadium and tungsten from the waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: In the step (3), the alkalinity of the analytical solution is controlled to be 5-10%; the molar ratio of the vanadium precipitation agent to the V2O5 in the vanadium-containing tungsten solution is (1.2-1.5):1; the vanadium precipitation agent is any one or a combination of calcium oxide, calcium hydroxide or calcium sulfate; the temperature during the vanadium precipitation reaction is 60-80°C and the time is 1-2h.

6. The method for separating vanadium and tungsten from waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: In the step (4), the pH of the solution after vanadium precipitation is adjusted to 9-12, and the molar ratio of the tungsten precipitation agent to WO3 in the solution is (1.2-1.5):1; the tungsten precipitation agent is any one or a combination of calcium carbonate, calcium phosphate, and calcium chloride. The temperature of the tungsten precipitation reaction is 80-100°C and the time is 1-2h.

7. The method for separating vanadium and tungsten from waste SCR denitration catalyst leachate by ion exchange resin according to claim 1, characterized in that: The preparation method of the modified polystyrene ion exchange resin is: S1. Add 4-chloromethylbenzaldehyde and o-aminophenol in a molar ratio of 1:(1-1.05) to ethanol, stir and react at 30-40° C. for 4-6 hours, heat to evaporate, cool in an ice-water bath and recrystallize to obtain 2-[(4-(chloromethyl)benzylidene)amino]phenol; S2, adding chloromethyl polystyrene resin to toluene, stirring and swelling, then adding N,N-bis(2-hydroxyethyl)ethylenediamine, heating to 70-80°C, stirring and reacting for 18-30h, then adding potassium carbonate and 2-[(4-(chloromethyl)benzylidene)amino]phenol, stirring and reacting for 18-24h, filtering, washing with water, ethanol, and drying in sequence to obtain a modified polystyrene resin; S3. Add the modified polystyrene resin to 1,4-dioxane, stir and swell, then add 1,4-butanesulfonate and sodium hydroxide aqueous solution, heat to 65-75°C, stir and react for 12-18h, filter, wash with water, ethanol, and dry in turn to obtain a modified polystyrene ion exchange resin.

8. The method for separating vanadium and tungsten from waste SCR denitration catalyst leachate by ion exchange resin according to claim 7, characterized in that: The mass ratio of chloromethyl polystyrene resin, N,N-bis(2-hydroxyethyl)ethylenediamine, potassium carbonate and 2-[(4-(chloromethyl)benzylidene)amino]phenol in S2 is 100:(200-350):(240-440):(270-490).

9. The method for separating vanadium and tungsten from waste SCR denitration catalyst leachate by ion exchange resin according to claim 7, characterized in that: The mass ratio of chloromethyl polystyrene resin, 1,4-butanesultone and sodium hydroxide in S3 is 100:(180-330):(54-95).

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