Method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalyst

Abstract

The invention belongs to the field of dangerous solid waste recovery and cyclic utilization, and relates to a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR (Selective Catalytic Reduction) catalyst, which comprises the following steps: obtaining waste SCR catalyst powder; mixing the waste SCR catalyst powder with a roasting agent step by step, and roasting to obtain a roasted material; wherein the roasting agent is a mixture of at least two alkaline substances, and at least one alkaline substance is a strong alkali substance; the roasted material is added into a leaching agent for a leaching reaction, solid-liquid separation is conducted after leaching is completed, leaching residues and a leaching agent are obtained, the leaching agent is a mixed solution of metal element compounds soluble in the leaching agent, and the leaching residues are metal element compounds insoluble in the leaching agent; the method is efficient and rapid, the extraction amount of vanadium and tungsten is increased, the cost is reduced, industrialization is easy to achieve, and potential industrial application prospects are achieved.

Description

Technical Field

[0001] The invention belongs to the field of recycling and cyclic utilization of hazardous solid wastes, and relates to a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst. Background Art

[0002] Waste SCR denitration catalyst contains important metal resources such as vanadium, tungsten, and titanium, which have great recycling value. According to the current market price, the recycling of these valuable metal resources will generate an output value of hundreds of millions of yuan. Therefore, the recycling of waste SCR denitration catalyst has important economic, environmental and social benefits.

[0003] At present, the method for recovering vanadium and tungsten from waste SCR denitration catalysts is to directly mix solids with solids in large quantities for roasting reaction, which makes the reaction effect poor. For example, the application number is CN112390285A, and the name is a method for recovering vanadium-titanium waste catalysts. Under the action of a reducing agent, the waste catalyst is subjected to a chlorination reaction with chlorine at a high temperature to generate gaseous chlorides, and the gaseous chlorides are condensed step by step to obtain solid phases containing W and Mo and liquid phases containing Ti and V respectively; then, a vanadium removal agent is added to the liquid phase containing Ti and V, and distilled to obtain a solid phase containing V and refined TiCl4;

[0004] A single calcining agent is added to the calcination reaction, so that the ambient temperature required at the beginning of the reaction is high, and the heating process is time-consuming and energy-consuming; for example, the application number is 2016107978809, and the name is a method for recovering a waste SCR catalyst, in which a calcination aid is added to the waste SCR catalyst, wherein the calcination aid is sodium carbonate, and the mixture is simultaneously crushed and stirred to obtain a mixture, and the mixture is calcined, and after calcination, it is impregnated with deionized water, and filtered to obtain a filtrate and a filter residue, and calcium fluoride is added to the filtrate to precipitate vanadium, tungsten and molybdenum, and the filter residue is washed with dilute hydrochloric acid, separated, and the precipitate is dissolved by hydrochloric acid impregnation, ammonia precipitation, and the slag is dissolved by adding ammonia, the filtrate is paratungstic acid / or ammonium molybdate, and the filter residue is ammonium metavanadate;

[0005] The existing methods for recovering vanadium and tungsten still have the problem of low leaching rate in actual production; for example, the application number is CN105648219A, and the name is a process method for recovering vanadium from honeycomb waste SCR catalyst. The waste catalyst is crushed, water is added to wash away dust and debris, and after drying and grinding, it is leached under high temperature and pressure, and filter residue and leaching liquid are obtained through solid-liquid separation. The filter residue is washed with deionized water to wash away sodium, tungsten and vanadium therein, and the washing water is recovered. Hydrochloric acid is added to the leaching liquid, and silicon impurities are filtered out. Hydrochloric acid is added, ion exchange and desorption are performed to obtain ammonium paratungstate and ammonium metavanadate, and ammonium salt is added to the mixed solution. The solid-liquid separation is dried, and ammonium metavanadate is precipitated and crystallized. However, the leaching rate is low in actual production, resulting in low value and impeded feasibility.

[0006] Therefore, it is necessary to design a method for efficiently extracting and separating vanadium, tungsten and titanium from the waste SCR catalyst to improve the above problems. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst.

[0008] The present invention provides a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst, the method comprising the following steps:

[0009] S1, obtaining spent SCR catalyst powder;

[0010] S2, mixing the waste SCR catalyst powder with a calcining agent in steps, and calcining to obtain a calcined material; wherein the calcining agent is a mixture of at least two alkaline substances, wherein at least one alkaline substance is a strong alkaline substance;

[0011] S3, adding the roasted material to a leaching agent to carry out a leaching reaction, and after the leaching is completed, performing solid-liquid separation to obtain leaching residue and leaching liquid, wherein the leaching liquid is a mixed solution of metal element compounds soluble in the leaching agent, and the leaching residue is a metal element compound insoluble in the leaching agent;

[0012] Furthermore, the waste SCR catalyst is a waste SCR denitration catalyst of a vanadium-tungsten system;

[0013] Further, in step S1, the particle size of the waste SCR catalyst powder is less than 100 mesh;

[0014] Further, in step S2, the step-by-step mixing method is:

[0015] Dividing the waste SCR catalyst powder and the calcining agent into several small portions and mixing them one by one to obtain several portions of mixed materials;

[0016] Mixing several portions of the mixed materials again as a whole;

[0017] Further, the amount of the calcining agent is 10%-100% of the mass of the waste SCR catalyst;

[0018] Further, the calcining agent is a mixture of a strong base substance and an alkali metal salt;

[0019] The alkali metal element in the alkali metal salt is the same as the metal element in the strong base substance;

[0020] Preferably, the alkali metal element is sodium;

[0021] The alkali metal salt is selected from any one of carbonate and bicarbonate;

[0022] Furthermore, in the calcining agent, the mass ratio of the alkali metal salt to the strong base substance is 0.25-4:1;

[0023] Further, in step S2, the calcination is performed in steps, specifically:

[0024] After the mixed material is subjected to a first calcination reaction at a first calcination temperature, the temperature is raised to a second calcination temperature for a second calcination reaction;

[0025] Preferably, the conditions for the first calcination reaction are:

[0026] The first calcination temperature is 500-600°C, and the first calcination reaction time is 0.5-2h;

[0027] The second calcination temperature is 700-850°C, and the second calcination reaction time is 0.5-2h;

[0028] Further, in step S3, the leaching agent is water, and the solid-liquid mass ratio of the roasted material to the leaching agent is 1:2-4;

[0029] Further, in step S3, the conditions of the leaching reaction are: heating the leaching system at 40-60° C., and the leaching time is 3-5 h;

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalysts of the present invention is efficient and rapid, reduces costs, increases the amount of vanadium and tungsten extracted, is easy to industrialize, and has potential industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The following drawings are only used to illustrate and explain the present invention, and are not used to limit the scope of the present invention, wherein:

[0033] Figure 1 : A schematic flow diagram of a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution, design method and advantages of the present invention clearer, the present invention is further described in detail by specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] like Figure 1 As shown, the present invention provides a method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst, the method comprising the following steps:

[0036] S1, obtaining spent SCR catalyst powder;

[0037] The waste SCR catalyst is a waste SCR denitration catalyst of a vanadium-tungsten system; the particle size of the waste SCR catalyst powder is less than 100 meshes;

[0038] S2, mixing the waste SCR catalyst powder with a calcining agent in steps, and calcining to obtain a calcined material; wherein the calcining agent is a mixture of at least two alkaline substances, wherein at least one alkaline substance is a strong alkaline substance;

[0039] The step-by-step mixing method is:

[0040] Dividing the waste SCR catalyst powder and the calcining agent into several small portions and mixing them one by one to obtain several portions of mixed materials;

[0041] Mixing several portions of the mixed materials again as a whole;

[0042] The amount of the calcining agent is 10%-100% of the mass of the waste SCR catalyst;

[0043] The calcining agent is a mixture of a strong alkaline substance and an alkali metal salt;

[0044] The alkali metal element in the alkali metal salt is the same as the metal element in the strong base substance;

[0045] The alkali metal element is sodium; the alkali metal salt is selected from any one of carbonate and bicarbonate;

[0046] In the calcining agent, the mass ratio of the alkali metal salt to the strong base substance is 0.25-4:1;

[0047] The calcination is performed in steps, wherein the mixed material is subjected to a first calcination reaction at a first calcination temperature, and then the temperature is raised to a second calcination temperature for a second calcination reaction;

[0048] The conditions of the first calcination reaction are: the first calcination temperature is 500-600°C, and the first calcination reaction time is 0.5-2h; the second calcination temperature is 700-850°C, and the second calcination reaction time is 0.5-2h;

[0049] S3, adding the roasted material to a leaching agent to carry out a leaching reaction, and after the leaching is completed, performing solid-liquid separation to obtain leaching residue and leaching liquid, wherein the leaching liquid is a mixed solution of metal element compounds soluble in the leaching agent, and the leaching residue is a metal element compound insoluble in the leaching agent;

[0050] The leaching agent is water, and the solid-liquid mass ratio of the roasted material to the leaching agent is 1:2-4;

[0051] The conditions of the leaching reaction are: heating the leaching system at 40-60°C, and the leaching time is 3-5h;

[0052] Example 1: The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 70 meshes; 100g of the waste SCR catalyst is weighed and mixed with 20g of sodium carbonate and 20g of sodium hydroxide in steps, wherein 100g of the waste SCR catalyst powder is first divided into several small portions and 20g of sodium carbonate and 20g of sodium hydroxide and mixed one by one to obtain several portions of mixed materials; and then the several portions of the mixed materials are mixed together as a whole again for roasting reaction, and during the roasting process, the mixture is first reacted at 500°C for 1h in a muffle furnace, and then reacted at 700°C for 1h to obtain a roasted material, and the roasted material is mixed with water according to a solid-liquid mass ratio of 1:3, and a water immersion reaction is carried out at 40°C for 3h. After the water immersion reaction is completed, solid-liquid separation is carried out, and the leachate is a sodium salt mixed solution containing tungsten and vanadium, and the leached slag is a sodium titanate solid;

[0053] According to the above specific process steps, the following results were obtained: the vanadium leaching rate was 88.95%, and the tungsten leaching rate was 88.47%;

[0054] Example 2

[0055] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 100 meshes; first, 100g of the waste SCR catalyst is weighed and mixed with 30g of sodium carbonate and 10g of sodium hydroxide in steps, wherein 100g of the waste SCR catalyst powder is first divided into several small portions and mixed with 30g of sodium carbonate and 10g of sodium hydroxide respectively, to obtain several portions of mixed materials; then, the several portions of the mixed materials are mixed together as a whole for roasting reaction, and the roasting reaction is carried out together, and during the roasting process, the reaction is first carried out at 600°C in a muffle furnace for 0.5h, and then at 700°C for 1.5h to obtain a roasted material, and the roasted material is mixed with water according to a solid-liquid mass ratio of 1:4, and a water immersion reaction is carried out at 50°C for 3h. After the water immersion reaction is completed, solid-liquid separation is carried out, and the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the leaching residue is a sodium titanate solid;

[0056] According to the above specific process steps, the following results were obtained: the vanadium leaching rate was 92.86%, and the tungsten leaching rate was 92.42%;

[0057] Example 3

[0058] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 200 meshes; 20g of the waste SCR catalyst is weighed and mixed with 6g of sodium carbonate and 2g of sodium hydroxide in steps, wherein 20g of the waste SCR catalyst powder is first divided into several small portions and mixed with 6g of sodium carbonate and 2g of sodium hydroxide respectively, to obtain several portions of mixed materials; and then the several portions of the mixed materials are mixed together as a whole again for roasting reaction, and during the roasting process, the reaction is first carried out at 600°C in a muffle furnace for 0.5h, and then at 700°C for 1.5h to obtain a roasted material, and the roasted material is mixed with water according to a solid-liquid mass ratio of 1:4, and a water immersion reaction is carried out at 60°C for 4h. After the water immersion reaction is completed, solid-liquid separation is carried out, and the leachate is a sodium salt mixed solution containing tungsten and vanadium, and the leached slag is a sodium titanate solid;

[0059] According to the above specific process steps, the following results were obtained: the vanadium leaching rate was 93.23%, and the tungsten leaching rate was 94.23%;

[0060] Comparative Example 1: The calcining agent is sodium carbonate, and other reaction conditions are the same as those of the present application;

[0061] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 100 meshes; 100g of the waste SCR catalyst is weighed and mixed with 40g of sodium carbonate for calcination reaction, and the calcination process is first reacted at 600°C in a muffle furnace for 0.5h, and then reacted at 700°C for 1.5h to obtain a calcined material, and the calcined material is mixed with water at a solid-liquid mass ratio of 1:4 for water leaching reaction for 4h, and after the water leaching reaction is completed, solid-liquid separation is performed, and the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the vanadium leaching rate is 78.53%, and the tungsten leaching rate is 82.38%;

[0062] Comparative Example 2: The calcination reaction was performed at one temperature, and other reaction conditions were the same as those of the present application;

[0063] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 100 meshes; 100g of the waste SCR catalyst is weighed and mixed with 30g of sodium carbonate and 10g of sodium hydroxide for calcination reaction, and the calcination process is carried out at 700°C for 2h to obtain a calcined material, and the calcined material is mixed with water at a solid-liquid mass ratio of 1:4 for water leaching reaction for 4h, and after the water leaching reaction is completed, solid-liquid separation is performed, and the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the vanadium leaching rate is 72.33%, and the tungsten leaching rate is 78.47%;

[0064] Comparative Example 3: The roasting agent is a mixture of sodium carbonate and sodium chloride, and other reaction conditions are the same as those of the present application;

[0065] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 100 meshes; 100g of the waste SCR catalyst is weighed and mixed with 30g of sodium carbonate and 10g of sodium chloride for calcination reaction, and the calcination process is first reacted at 600°C in a muffle furnace for 0.5h, and then reacted at 700°C for 1.5h to obtain a calcined material, and the calcined material is mixed with water at a solid-liquid mass ratio of 1:4 for water leaching reaction for 4h, and after the water leaching reaction is completed, solid-liquid separation is performed, and the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the vanadium leaching rate is 75.72%, and the tungsten leaching rate is 85.23%;

[0066] Comparative Example 4: The mixing ratio of the calcining agent, sodium carbonate and sodium hydroxide, is not within the range set in this application, and the other reaction conditions are the same as those in this application;

[0067] The waste SCR denitration catalyst of the vanadium-tungsten system is cleaned, dried, mechanically crushed, and ground to obtain a waste SCR catalyst powder, wherein the particle size of the waste SCR catalyst powder is less than 100 meshes; 100g of the waste SCR catalyst is weighed and mixed with 35g of sodium carbonate and 5g of sodium chloride for calcination reaction, and the calcination process is first reacted at 600°C for 1h in a muffle furnace and then at 700°C for 1h to obtain a calcined material, and the calcined material is mixed with water at a solid-liquid mass ratio of 1:4 for water leaching reaction for 4h, and after the water leaching reaction is completed, solid-liquid separation is performed, and the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the vanadium leaching rate is 52.56%, and the tungsten leaching rate is 61.84%;

[0068] Therefore, in Example 1, Example 2 and Example 3, the waste SCR catalyst powder is mixed with the calcining agent in steps, and calcined in steps to obtain a calcined material, wherein the calcining agent is a mixture of at least two alkaline substances, wherein at least one alkaline substance is a strong alkaline substance, and the calcined material is added to the leaching agent to carry out a leaching reaction, and after the leaching is completed, solid-liquid separation is carried out to obtain leached slag and a leaching solution, wherein the leaching solution is a sodium salt mixed solution containing tungsten and vanadium, and the vanadium and tungsten leaching rates separated from the sodium salt mixed solution of tungsten and vanadium are between 89% and 94%; compared with Comparative Examples 1 to Comparative Examples 4, in which the calcining agent is a single calcining agent, or the calcination reaction is a temperature, or at least one of the calcining agent mixture is not a strong alkaline substance, or the calcining agent mixing ratio is different, the vanadium and tungsten leaching rates are between 52% and 80%, and the method of the present application is efficient and fast, and the vanadium and tungsten leaching rates obtained from the waste SCR catalyst are increased by 10% to 30%;

[0069] It can be seen from Example 2 and Example 3 that the vanadium and tungsten contents extracted and separated from the waste SCR catalyst powder with a particle size of less than 200 meshes are close to the vanadium and tungsten contents extracted and separated from the waste SCR catalyst powder with a particle size of less than 100 meshes, and both can increase the content of vanadium and tungsten extracted and separated. Therefore, the particle size of the waste SCR catalyst powder is less than 100 meshes;

[0070] It is worth noting that the process for extracting and separating vanadium and tungsten from waste SCR denitration catalyst of the present invention comprises mixing waste SCR catalyst powder with a calcining agent in steps, and calcining in steps to obtain a calcined material; mixing waste SCR catalyst powder with a calcining agent in steps is conducive to uniform mixing, and calcining in steps is conducive to sufficient calcination reaction; the calcining agent is a mixture of at least two alkaline substances, wherein at least one alkaline substance is a strong alkaline substance; in the step-by-step calcination reaction process, the mixed material is subjected to a first calcination reaction at a first calcination temperature, and then the temperature is raised to a second calcination temperature for a second calcination reaction; energy consumption and time are saved, and the reaction amount of the calcining agent and the waste SCR catalyst is effectively increased; the calcined material is added to a leaching agent for leaching The reaction is carried out, and after the leaching is completed, solid-liquid separation is carried out to obtain leaching residue and leachate, wherein the leachate is a mixed solution of metal element compounds soluble in the leaching agent, that is, a sodium salt mixed solution containing tungsten and vanadium; wherein, the roasting agent of the present invention is a mixture of at least two alkaline substances, and compared with the roasting agent in the prior art, sodium hydroxide is added, and two roasting temperature environments are set, which saves energy consumption and makes full use of the time of the heating process, so that part of the reaction is carried out in advance, saving time cost, so that vanadium, tungsten and titanium are extracted and separated from the waste SCR catalyst efficiently and quickly, and the leaching agent can meet the demand by using water, the cost is reduced, the cost is reduced and the efficiency is increased, the extraction amount of vanadium and tungsten is increased, it is easy to realize industrialization, and has potential industrial application prospects.

[0071] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for extracting and separating metal elements from a waste SCR catalyst, characterized in that: The method comprises the following steps: S1, obtaining spent SCR catalyst powder; S2, mixing the waste SCR catalyst powder with a calcining agent in steps, and calcining to obtain a calcined material; Wherein, the calcining agent is a mixture of at least two alkaline substances, at least one of which is a strong alkaline substance; S3, adding the roasted material to a leaching agent to carry out a leaching reaction, and after the leaching is completed, performing solid-liquid separation to obtain leaching residue and leaching liquid, wherein the leaching liquid is a mixed solution of metal element compounds soluble in the leaching agent, and the leaching residue is a metal element compound insoluble in the leaching agent.

2. A method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to claim 1, characterized in that: The waste SCR catalyst is a waste SCR denitration catalyst of a vanadium-tungsten system.

3. The method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalyst according to claim 1, characterized in that: In step S1, the particle size of the spent SCR catalyst powder is less than 100 meshes.

4. The method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalyst according to claim 1, characterized in that: In step S2, the step-by-step mixing method is: Dividing the waste SCR catalyst powder and the calcining agent into several small portions and mixing them one by one to obtain several portions of mixed materials; Several portions of the mixed materials are mixed again as a whole.

5. The method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalyst according to claim 1, characterized in that: The amount of the calcining agent used is 10%-100% of the mass of the waste SCR catalyst.

6. The method for efficiently extracting and separating vanadium, tungsten and titanium from waste SCR catalyst according to claim 1, characterized in that: The calcining agent is a mixture of a strong base substance and an alkali metal salt; The alkali metal element in the alkali metal salt is the same as the metal element in the strong base substance; Preferably, the alkali metal element is sodium; The alkali metal salt is selected from any one of carbonate and bicarbonate.

7. A method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to claim 6, characterized in that: In the calcining agent, the mass ratio of the alkali metal salt to the strong base substance is 0.25-4:

1.

8. The method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to claim 1, characterized in that: In step S2, the calcination is performed in steps, specifically: After the mixed material is subjected to a first calcination reaction at a first calcination temperature, the temperature is raised to a second calcination temperature for a second calcination reaction; Preferably, the conditions for the first calcination reaction are: The first calcination temperature is 500-600°C, and the first calcination reaction time is 0.5-2h; The second calcination temperature is 700-850°C, and the second calcination reaction time is 0.5-2h.

9. The method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to claim 1, characterized in that: In step S3, the leaching agent is water; The solid-liquid mass ratio of the roasted material to the leaching agent is 1:2-4.

10. The method for efficiently extracting and separating vanadium, tungsten and titanium from a waste SCR catalyst according to claim 8, characterized in that: In step S3, the conditions of the leaching reaction are: The leaching reaction temperature is 40-60°C, and the leaching reaction time is 3-5h.

Images