Method for recovering titanium from titanium waste residue, titanium dioxide and preparation method of scr denitration catalyst

Abstract

The application relates to the field of titanium recovery, and discloses a method for recovering titanium from titanium waste residues, a preparation method of titanium dioxide and an SCR denitration catalyst. The method for recovering titanium from titanium waste residues provided by the application comprises the following steps: 1) adding a buffer in the presence of water to obtain solution A; 2) performing first contact of solution A with titanium waste residues to obtain solution B; 3) performing second contact of solution B with an alkali to obtain solution C; and 4) performing centrifugal separation and drying of solution C to obtain titanium dioxide. According to the method, the cost expenditure for environmental protection is reduced, the cost is low, the operation is simple, the equipment is simple, the titanium compounds in the waste residues can be completely converted into anatase titanium dioxide, and the product can be reused for preparation of an SCR denitration catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to titanium recovery, in particular, to a method for recovering titanium from titanium waste residue, a preparation method of titanium dioxide and an SCR denitration catalyst. BACKGROUND

[0002] Titanium dioxide is a well-known material with various uses, and its applications include cosmetics, personal care products, plastics, surface coatings, catalyst support materials, etc. As for the crystal form of titanium dioxide, three types can be obtained, namely, rutile, anatase and brookite, among which, anatase is widely used in catalysts and solar cells.

[0003] Organic titanium and titanium tetrachloride are common raw materials in the titanium industry, which are often used in the fields of high-purity titanium industry, catalyst industry, etc. Such industries often produce titanium-containing by-products or waste, and such raw materials are prone to hydrolysis and often contain organic matter. Generally, such waste is treated by hydrolysis method, and the obtained residue is difficult to be used in the coating field due to low purity and insufficient whiteness, and also cannot be used in the field of cosmetics due to impurities, and therefore is often landfilled. SUMMARY

[0004] The purpose of the present application is to overcome the problem of difficult treatment of titanium waste residue in the prior art, and to provide a method for recovering titanium from titanium waste residue, which has the effects of reducing environmental protection cost, low cost, simple operation and simple equipment, and can convert all titanium compounds in the waste residue into anatase titanium dioxide, and the product can be used for preparing an SCR denitration catalyst.

[0005] In order to achieve the above-mentioned purpose, the present application provides a method for recovering titanium from titanium waste residue, wherein the method comprises the following steps:

[0006] 1) adding a buffer in the presence of water to obtain solution A;

[0007] 2) allowing solution A to contact with titanium waste residue for the first time to obtain solution B;

[0008] 3) allowing solution B to contact with alkali for the second time to obtain solution C;

[0009] 4) centrifuging and drying solution C to obtain titanium dioxide,

[0010] the buffer is one or more of a mixture of acetic acid and sodium acetate, a mixture of ammonia and ammonium chloride, ammonium carbonate and ammonium bicarbonate,

[0011] the amount of the buffer is such that the pH value of solution A is 7.1-11,

[0012] The amount of the titanium waste residue is such that the pH value of the solution B is 4-7,

[0013] The amount of the base is such that the pH value of the solution C is 7.1-11,

[0014] The mass amount ratio of acetic acid to sodium acetate in the mixture of acetic acid and sodium acetate is 1:10-1000,

[0015] The mass amount ratio of ammonia water to ammonium chloride in the mixture of ammonia water and ammonium chloride is 1:25-3000, calculated based on NH3·H2O.

[0016] Preferably, the amount of the buffer is such that the pH value of the solution A is 7.1-9.5;

[0017] Preferably, the amount of the titanium waste residue is such that the pH value of the solution B is 4.5-6.5;

[0018] Preferably, the amount of the base is such that the pH value of the solution C is 7.1-9.5;

[0019] Preferably, the amount of the base is such that the solution C restores to the pH value of the solution A.

[0020] Preferably, the titanium waste residue contains one or more of titanium tetrachloride, alkoxy titanium and chloro-substituted alkoxy titanium.

[0021] Preferably, the base is a base with a pK b value of 3-12;

[0022] Preferably, the base is one or more of ammonium carbonate, ammonium bicarbonate, ammonia water, ammonium acetate and ammonium citrate.

[0023] Preferably, the method further comprises the step of repeating the operation of steps 2) and 3).

[0024] Preferably, the conditions of the centrifugal separation include a temperature of 1-40℃, a rotation speed of 500-10000 rpm and a time of 3-180 min.

[0025] Preferably, the conditions of the drying include a temperature of 40-150℃ and a time of 1-48 h; preferably, the conditions of the drying include a temperature of 70-100℃ and a time of 1-12 h.

[0026] In the second aspect of the present application, a titanium dioxide is provided, wherein the titanium dioxide is prepared by the method for recovering titanium from titanium waste residue according to any one of the first aspect of the present application.

[0027] Preferably, the crystal phase of the titanium dioxide is an anatase phase.

[0028] In a third aspect, the application provides a method for preparing an SCR denitration catalyst, wherein the method comprises the steps of preparing titanium dioxide by the method for recovering titanium from titanium waste residue according to any one of the first aspect of the application, and preparing the SCR denitration catalyst using the titanium dioxide as a raw material.

[0029] The method for recovering titanium from titanium waste residue provided by the application reduces the cost of purchasing titanium dioxide in the treatment of hazardous waste and the production of an SCR denitration catalyst, and the equipment is easy to obtain and the operation steps are simple, and the risk of liquid splashing is not easy to occur in the operation process, and industrialized production is easy to realize, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a graph showing the conversion of nitrogen oxides at different temperatures. DETAILED DESCRIPTION

[0031] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the application. Any numerical values need not be a precision as the same is understood in the art. For values which are not critical, and which can be extrapolated from the ranges disclosed herein, the application is intended to include all such values that are within the scope of the ranges.

[0032] According to a first aspect of the application, a method for recovering titanium from titanium waste residue is provided, characterized in that the method comprises the following steps:

[0033] 1) adding a buffer in the presence of water to obtain solution A;

[0034] 2) allowing solution A to be in first contact with titanium waste residue to obtain solution B;

[0035] 3) allowing solution B to be in second contact with a base to obtain solution C;

[0036] 4) centrifuging and drying solution C to obtain titanium dioxide,

[0037] the buffer is one or more of a mixture of acetic acid and sodium acetate, a mixture of ammonia and ammonium chloride, ammonium carbonate and ammonium bicarbonate,

[0038] the amount of the buffer is such that the pH value of solution A is 7.1-11,

[0039] the amount of the titanium waste residue is such that the pH value of solution B is 4-7,

[0040] the amount of the base is such that the pH value of solution C is 7.1-11,

[0041] The mass amount ratio of acetic acid to sodium acetate in the mixture of acetic acid and sodium acetate is 1:10-1000,

[0042] The mass amount ratio of ammonia water to ammonium chloride in the mixture of ammonia water and ammonium chloride is 1:25-3000, calculated as NH3-H2O.

[0043] According to the present application, preferably, the mass amount ratio of acetic acid to sodium acetate in the mixture of acetic acid and sodium acetate is 1:50-150; more preferably, the mass amount ratio of acetic acid to sodium acetate in the mixture of acetic acid and sodium acetate is 1:80-100.

[0044] According to the present application, preferably, the mass amount ratio of ammonia water to ammonium chloride in the mixture of ammonia water and ammonium chloride is 1:200-400, calculated as NH3-H2O; more preferably, the mass amount ratio of ammonia water to ammonium chloride is 1:200-300, calculated as NH3-H2O; further preferably, the mass amount ratio of ammonia water to ammonium chloride is 1:250-300, calculated as NH3-H2O.

[0045] According to the present application, in order to ensure that the finally obtained product is anatase titanium dioxide, and that the titanium-containing compounds in the titanium waste residue can be completely converted into titanium dioxide, preferably, the amount of the buffer is such that the pH value of the solution A is 7.1-9.5,

[0046] As specific examples of the amount of the buffer such that the pH value of the solution A is, for example, 7.1, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.3, 9.4, 9.5, 9.6, 9.8, 10, 10.5, 11, etc., and the range constituted by any two of the above.

[0047] According to the present application, preferably, the amount of the titanium waste residue is such that the pH value of the solution B is 4.5-6.5.

[0048] As specific examples of the amount of the titanium waste residue such that the pH value of the solution B is, for example, 4, 4.2, 4.4, 4.6, 4.2, 5, 5.2, 5.4, 5.6, 5.8, 6, 6.2, 6.4, 6.5, 6.6, 6.8, 7, etc., and the range constituted by any two of the above.

[0049] According to the present application, preferably, the amount of the base is such that the pH value of the solution C is 5-10.

[0050] As the amount of the buffer, examples of the pH value of the solution A include 7.1, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.3, 9.4, 9.5, 9.6, 9.8, 10, 10.5, 11, and the like, and a range between any two of the above.

[0051] In a particularly preferred embodiment of the present application, the amount of the base is such that the pH value of the solution C is restored to that of the solution A.

[0052] In the present application, first, water and a buffer are mixed to obtain a solution A.

[0053] In the present application, by adjusting the pH value using a buffer and a base, it is possible to ensure that the final product is titanium dioxide, thereby improving the recycling rate, protecting the environment, and reducing costs.

[0054] According to the present application, in order to make the operation more simple, preferably, the buffer is ammonium carbonate and / or ammonium bicarbonate; more preferably, the buffer is ammonium bicarbonate. When ammonium carbonate and / or ammonium bicarbonate is used, the operation is more convenient because ammonium carbonate and ammonium bicarbonate are buffers themselves and can also act as a base.

[0055] In the present application, the solution A is first contacted with a titanium waste residue, and the first contact is not particularly limited and can be performed under normal conditions (e.g., at room temperature of 5-40°C, and the time is not particularly limited). In step 2), the titanium waste residue is slowly added to the solution A to obtain a solution B.

[0056] According to the present application, the titanium waste residue is a titanium-containing waste residue commonly produced in the art, and is not particularly limited, such as organic titanium process waste residue, titanium tetrachloride, and the like, and preferably, the titanium waste residue contains one or more of titanium tetrachloride, titanium alkoxide, and chloro-substituted titanium alkoxide.

[0057] In the present application, the solution B is second contacted with a base, and the second contact is not particularly limited and can be performed under normal conditions (e.g., at room temperature of 5-40°C, and the time is not particularly limited). In step 3), the base is added to the solution B to obtain a solution C.

[0058] According to the present application, in order to more effectively control the pH value, preferably, the base is a base having a pK b value of 3-12; more preferably, the base is one or more of ammonium carbonate, ammonium bicarbonate, aqueous ammonia, ammonium acetate, and ammonium citrate. When a strong base having a pK b value of 3 or less is used, the pH value of the solution rises too fast, and the pH value cannot be effectively controlled, and therefore, in the present application, a base having a pKb a base having a value of 3-12.

[0059] According to the present application, for the purpose of further stabilizing the pH of the hydrolysis system, the operation of step 2) and step 3) can be repeated, preferably, the number of times of said repeated operation is 1-7, for example, it can be 1 time, 2 times, 3 times, 4 times, 5 times, 6 times or 7 times.

[0060] Specifically, the repeated operation of step 2) and step 3) is illustrated by 1 time, and the specific steps are as follows,

[0061] 1) adding a buffer in the presence of water to obtain solution A;

[0062] 2) performing a first contact of solution A with organic titanium waste residue to obtain solution B;

[0063] 3) performing a second contact of solution B with a base to obtain solution C;

[0064] 3-1) performing a first contact of solution C with organic titanium waste residue to obtain solution B1;

[0065] 3-2) performing a second contact of solution B1 with a base to obtain solution C1;

[0066] 4) performing centrifugal separation and drying of solution C1 to obtain titanium dioxide.

[0067] In the present application, before step 4) is performed, a step of stirring solution C can also be included, and there is no particular limitation on said stirring operation, it is only required to stir the mixture in solution C to be uniform, and preferably, the time of said stirring is 0.2-1h.

[0068] Then, solution C is subjected to centrifugal separation and drying to obtain anatase titanium dioxide.

[0069] According to the present application, there is no particular limitation on said centrifugal separation operation, and various centrifugal separation methods in the art can be used, and preferably, in step 4), the conditions of said centrifugal separation include: temperature of 1-40℃, rotation speed of 500-10000rpm, and time of 3-180min.

[0070] According to the present application, there is no particular limitation on said drying operation, and various drying methods in the art can be used, and preferably, the conditions of said drying include: temperature of 40-150℃, and time of 1-48h; more preferably, the conditions of said drying include: temperature of 70-100℃, and time of 1-12h.

[0071] According to a second aspect of the present application, there is provided a titanium dioxide prepared by the method for recovering titanium from titanium waste residue according to the first aspect of the present application.

[0072] According to the present application, preferably, the crystal phase of the titanium dioxide is anatase phase.

[0073] According to the third aspect of the present application, there is provided a method for preparing an SCR De-NOx catalyst, which comprises the steps of preparing titanium dioxide by the method for recovering titanium from titanium waste residue according to the first aspect of the present application, and preparing an SCR De-NOx catalyst using the titanium dioxide as raw material.

[0074] The present application will be described in detail below by way of examples, but the present application is not limited to the following examples.

[0075] XRD detection equipment: purchased from Japan, model SmartLab.

[0076] Example 1

[0077] 1) 0.6g of ammonium carbonate was mixed with 7.5ml of water at 25℃ to obtain solution A with pH = 9.4;

[0078] 2) The titanium waste residue was slowly added to solution A until the pH = 5.1 to obtain solution B, and white precipitate was observed in solution B;

[0079] 3) Ammonium carbonate was added to solution B to make the pH value of the solution 9.4 to obtain solution C;

[0080] 4) After stirring solution C for 0.5h, centrifugal separation was carried out (temperature 25℃, speed 6000rpm, 5min) and then dried at 80℃ for 12 hours to obtain titanium dioxide S1,

[0081] It was confirmed by XRD detection that it was pure anatase titanium dioxide.

[0082] Example 2

[0083] 1) 0.7g of ammonium carbonate was mixed with 7.5ml of water at 25℃ to obtain solution A with pH = 9.1;

[0084] 2) The titanium waste residue was slowly added to solution A until the pH = 5.3 to obtain solution B, and white precipitate was observed in solution B;

[0085] 3) Ammonium carbonate was added to solution B to make the pH value of the solution 9.1 to obtain solution C;

[0086] 3-1) The titanium waste residue was slowly added to solution C until the pH = 5.3 to obtain solution B1;

[0087] 3-2) Ammonium carbonate was added to solution B1 to make the pH value of the solution 9.1 to obtain solution C1;

[0088] 3-3) Slowly add titanium waste residue to solution C1 to pH = 5.3 to obtain solution B2;

[0089] 3-4) Add ammonium carbonate to solution B2 to make the pH value of the solution 9.1 to obtain solution C2;

[0090] 8) After stirring solution C2 for 0.5 h, centrifugal separation is carried out (temperature 25℃, speed 6000 rpm, 6 min) and then drying at 80℃ for 12 hours to obtain titanium dioxide S2,

[0091] It is confirmed by XRD detection that it is pure anatase titanium dioxide.

[0092] Example 3

[0093] 1) At 25℃, mix 1.25g of ammonium carbonate with 15ml of water to obtain solution A with pH = 9.3;

[0094] 2) Slowly add titanium waste residue to solution A to pH = 4.8 to obtain solution B, and white precipitate can be seen in solution B;

[0095] 3) Add ammonium carbonate to solution B to make the pH value of the solution 9.3 to obtain solution C;

[0096] 3-1) Slowly add titanium waste residue to solution C to pH = 4.8 to obtain solution B1;

[0097] 3-2) Add ammonium carbonate to solution B1 to make the pH value of the solution 9.3 to obtain solution C1;

[0098] 3-3) Slowly add titanium waste residue to solution C1 to pH = 4.8 to obtain solution B2;

[0099] 3-4) Add ammonium carbonate to solution B2 to make the pH value of the solution 9.3 to obtain solution C2;

[0100] 8) After stirring solution C2 for 0.5 h, centrifugal separation is carried out (temperature 25℃, speed 6000 rpm, 6 min) and then drying at 80℃ for 12 hours to obtain titanium dioxide S2,

[0101] It is confirmed by XRD detection that it is pure anatase titanium dioxide.

[0102] Example 4

[0103] 1) At 25℃, mix 7.906g of ammonium carbonate with 50ml of water to obtain solution A with pH = 7.1;

[0104] 2) Slowly add titanium waste residue to solution A to pH = 6.0 to obtain solution B, and white precipitate can be seen in solution B;

[0105] 3) Adding ammonium carbonate to solution B to make the pH of the solution 7.1 to obtain solution C;

[0106] 3-1) Slowly adding titanium waste residue to solution C to make the pH = 6.0 to obtain solution B1;

[0107] 3-2) Adding ammonium carbonate to solution B1 to make the pH of the solution 7.1 to obtain solution C1;

[0108] 3-3) Slowly adding titanium waste residue to solution C1 to make the pH = 6.0 to obtain solution B2;

[0109] 3-4) Adding ammonium carbonate to solution B2 to make the pH of the solution 7.1 to obtain solution C2;

[0110] 3-5) Slowly adding titanium waste residue to solution C2 to make the pH = 6.0 to obtain solution B3;

[0111] 3-6) Adding ammonium carbonate to solution B3 to make the pH of the solution 7.1 to obtain solution C3;

[0112] 10) After stirring solution C3 for 0.5 h, centrifugal separation was carried out (temperature 25°C, speed 6000 rpm, 6 min) and then drying at 80°C for 12 hours to obtain titanium dioxide S4,

[0113] It was confirmed by XRD detection that it was pure anatase titanium dioxide.

[0114] Example 5

[0115] 1) Mixing 0.9 g of ammonia water and ammonium chloride (the weight ratio of ammonia water to ammonium chloride is 1:100) and 7.5 ml of water at 25°C to obtain solution A with pH = 8.9;

[0116] 2) Slowly adding titanium waste residue to solution A to make the pH = 6.1 to obtain solution B, and white precipitate can be seen in solution B;

[0117] 3) Adding ammonia water to solution B to make the pH of the solution 8.9 to obtain solution C;

[0118] 3-1) Slowly adding titanium waste residue to solution C to make the pH = 6.1 to obtain solution B1;

[0119] 3-2) Adding ammonia water to solution B1 to make the pH of the solution 8.9 to obtain solution C1;

[0120] 3-3) Slowly adding titanium waste residue to solution C1 to make the pH = 6.1 to obtain solution B2;

[0121] 3-4) Ammonia water was added to solution B2 to make the pH value of the solution 8.9, to obtain solution C2;

[0122] 8) After stirring solution C2 for 0.5 h, centrifugal separation was carried out (temperature 25°C, speed 6000 rpm, 6 min), and then drying was carried out at 80°C for 12 hours, to obtain titanium dioxide S5,

[0123] It was confirmed by XRD detection that it was pure anatase titanium dioxide.

[0124] Example 6

[0125] 1) At 25°C, 0.7 g acetic acid and sodium acetate (the weight ratio of acetic acid to sodium acetate was 1:275) were mixed with 7.5 ml water to obtain solution A with pH = 9.0;

[0126] 2) Titanium waste residue was slowly added to solution A to make the pH value 6.5, to obtain solution B, and white precipitate was observed in solution B;

[0127] 3) Ammonia water was added to solution B to make the pH value of the solution 9.0, to obtain solution C;

[0128] 3-1) Titanium waste residue was slowly added to solution C to make the pH value 6.5, to obtain solution B1;

[0129] 3-2) Ammonia water was added to solution B1 to make the pH value of the solution 9.0, to obtain solution C1;

[0130] 3-3) Titanium waste residue was slowly added to solution C1 to make the pH value 6.5, to obtain solution B2;

[0131] 3-4) Ammonia water was added to solution B2 to make the pH value of the solution 9.0, to obtain solution C2;

[0132] 8) After stirring solution C2 for 0.5 h, centrifugal separation was carried out (temperature 25°C, speed 6000 rpm, 6 min), and then drying was carried out at 80°C for 12 hours, to obtain titanium dioxide S6,

[0133] It was confirmed by XRD detection that it was pure anatase titanium dioxide.

[0134] Comparative Example 1

[0135] 1) At 25°C, 5 g ammonium carbonate was mixed with 15 ml water to obtain solution A with pH = 12.1;

[0136] 2) Titanium waste residue was slowly added to solution A to make the pH value 7.2, to obtain solution B, and white precipitate was observed in solution B, and during the addition of titanium waste residue, the liquid had obvious splashing phenomenon;

[0137] 3) Add ammonium carbonate to solution B to make the pH of the solution 12.1, to obtain solution C;

[0138] 4) After stirring solution C for 0.5h, centrifugal separation is carried out (temperature 25°C, speed 6000rpm, 5min) and then drying at 80°C for 12h to obtain titanium dioxide D1,

[0139] The crystal phase is confirmed by XRD detection to contain anatase and rutile.

[0140] Comparative Example 2

[0141] 1) At 25°C, mix 1.25g ammonium carbonate with 15ml water to obtain solution A with pH=9.3;

[0142] 2) Slowly add titanium waste residue to solution A to pH=0.3 to obtain solution B,

[0143] At this time, the titanium residue is completely dissolved and the solution is clear.

[0144] Test Example 1

[0145] The titanium dioxide obtained in Example 1 or commercial anatase titanium dioxide, ammonium metavanadate are mixed in proportion (dose ratio converted to oxides is 1wt% V2O5:99wt% V2O5), water is added and heated to dissolve, stirred uniformly and heated to dryness. The obtained solid is dried at 100°C overnight and calcined at 550°C for 2h to obtain a catalyst.

[0146] Take 100mg catalyst and test for 60000h -1 Catalyst activity evaluation is carried out at space velocity, gas components are 500ppm NO+550ppm NH3+2vol.% O2+N2, nitrogen oxide conversion rate is tested at different temperatures, and the results are shown in Figure 1 .

[0147] Figure 1 is a graph showing nitrogen oxide conversion rate at different temperatures, from which it can be seen that the denitration efficiency of Example 1 (triangle symbol in the graph, or Example-1) is similar to or slightly higher than that of the reference sample (circle symbol in the graph, or Reference) prepared using anatase raw material at the whole temperature range.

[0148] Table 1

[0149]

[0150] From the results in Table 1, it can be seen that anatase titanium dioxide can be obtained when the method of the present application is used, and the titanium compounds in the waste residue can be completely converted into titanium dioxide.

[0151] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for recovering titanium from titanium waste residue, characterized by, The method comprises the following steps: 1) adding a buffer in the presence of water to obtain solution A; 2) subjecting solution A to a first contact with titanium waste residue to obtain solution B; 3) subjecting solution B to a second contact with a base to obtain solution C; 4) subjecting solution C to centrifugal separation and drying to obtain titanium dioxide, wherein the buffer is one or more of a mixture of acetic acid and sodium acetate, a mixture of ammonia and ammonium chloride, ammonium carbonate and ammonium bicarbonate, the amount of the buffer is such that the pH value of solution A is 7.1-11, the amount of the titanium waste residue is such that the pH value of solution B is 4-7, the amount of the base is such that the pH value of solution C is 7.1-11, in the mixture of acetic acid and sodium acetate, the mass amount ratio of acetic acid to sodium acetate is 1:10-1000, in the mixture of ammonia and ammonium chloride, the mass amount ratio of ammonia to ammonium chloride, calculated as NH3·H2O, is 1:25-3000, the titanium waste residue contains one or more of titanium tetrachloride, titanium alkoxide and chloro-substituted titanium alkoxide, the crystal phase of the titanium dioxide is anatase phase.

2. The method of claim 1, wherein, the amount of the buffer is such that the pH value of solution A is 7.1-9.

5.

3. The method of claim 1, wherein, the amount of the titanium waste residue is such that the pH value of solution B is 4.5-6.

5.

4. The method of claim 1, wherein, the amount of the base is such that the pH value of solution C is 7.1-9.

5.

5. The method of claim 1, wherein, the amount of the base is such that solution C returns to the pH value of solution A.

6. The method of claim 1, wherein, In step 3), the base is a base having a pK b value of 3-12.

7. The method of claim 6, wherein, the base is one or more of ammonium carbonate, ammonium bicarbonate, ammonia, ammonium acetate and ammonium citrate.

8. The method of claim 1, wherein, Before step 4) is performed, the method further comprises a step of repeating steps 2) and 3).

9. The method of claim 1, wherein, In step 4), the centrifugal separation conditions include a temperature of 1-40℃, a rotation speed of 500-10000 rpm and a time of 3-180 min.

10. The method of claim 1, wherein, In step 4), the drying conditions include a temperature of 40-150℃ and a time of 1-48 h.

11. The method of claim 1, wherein, In step 4), the drying conditions include a temperature of 70-100℃ and a time of 1-12 h.

12. Titanium dioxide, characterized in that Prepared by the method for recovering titanium from titanium waste residue according to any one of claims 1-11.

13. A method for producing an SCR De-NOx catalyst, characterized by, The method comprises the steps of preparing titanium dioxide by the method for recovering titanium from titanium waste residue according to any one of claims 1-11, and preparing an SCR denitration catalyst using the titanium dioxide as a raw material.

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