Method for secondary forming of titanium silicalite TS-1 waste powder

Abstract

The application belongs to the technical field of catalyst forming, and particularly relates to a method for secondary forming of titanium silicalite TS-1 waste powder, which comprises the following steps: S1, grinding titanium silicalite TS-1 waste powder to 60 mesh or less, adding a pore forming agent and mixing, and then adding TS-1 mother liquor and kneading to obtain a cohesive block; S2, extruding the cohesive block into a wet base strip to obtain a wet base strip-shaped catalyst; S3, drying the wet base strip-shaped catalyst to obtain a dry base strip-shaped catalyst; and S4, calcining the dry base strip-shaped catalyst to obtain an extruded strip-shaped catalyst. The TS-1 catalyst prepared by the application is used for various oxidation reactions such as olefin epoxidation, aromatic hydroxylation, ketone ammoxidation, alkane selective oxidation, oxidative desulfurization and alcohol oxidation, realizes secondary utilization of the waste powder and the TS-1 mother liquor, reduces the catalyst preparation cost, reduces environmental pollution, and the mechanical strength of the secondary extruded strip-shaped TS-1 catalyst is 1.5 times that of the prior art.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of catalyst forming technology, and more particularly to a method for secondary forming of titanium silicalite TS-1 waste powder. BACKGROUND

[0002] Titanium silicalite TS-1 is a kind of heteroatomic molecular sieve containing titanium atoms in the framework, which was first hydrothermally synthesized by Taramasso et al. in 1983 (US4410501). The oxidation system composed of TS-1 and hydrogen peroxide shows excellent catalytic activity for various selective oxidation reactions, and has great application potential in the field of selective oxidation, thus attracting extensive attention from researchers.

[0003] Most of the TS-1 catalytic oxidation reactions are carried out in fixed bed reactors, which requires the catalyst to have certain shape and strength. Extrusion is one of the most commonly used forming methods, which generally involves mixing active components, binders, etc. to form a wet block, then extruding it into a certain strength strip with an extruder, and finally crushing the strip into the size required for industrial application. The following is a typical extrusion forming method of TS-1:

[0004] Patent CN1346705 (application number CN0114050.9) provides a preparation method of a composite catalyst, which is composed of 2.0% to 95.0% of MFI structure titanium silicalite and 5.0% to 98.0% of inorganic oxide. The titanium silicalite is synthesized by hydrothermal method, and the inorganic oxide is selected from one or more of TiO2, SiO2, ZrO2, Al2O3, Na2O, K2O, CaO, and PbO, and the composite catalyst is formed by extrusion or spraying.

[0005] On this basis, patent CN1398674 (application number CN02126775.8) adopts an in-situ forming method, which introduces inorganic oxide into the hydrothermal synthesis system of titanium silicalite, so that the titanium silicalite grows in-situ on the inorganic oxide. The obtained composite catalyst can be directly used in fixed bed or moving bed reaction devices. In addition, patents CN1554483, CN101264453, etc. also provide other methods for preparing and forming catalysts in-situ, and the carriers used include graphite and diatomite, etc.

[0006] Patent CN1600428 (application number CN03126438.7) discloses a preparation method of a molecular sieve catalyst containing MFI structure. The method combines MFI structure molecular sieve with alkaline silica gel with a pH of 8 to 10, uses ammonia water or tetraethylammonium hydroxide as a gelatinizing agent, and uses sesbania powder as an auxiliary agent for extrusion or tabletting, to form a catalyst with strength and regeneration performance that can meet the requirements of fixed bed process.

[0007] Extrusion molding can use alumina, silica, titanium dioxide and other oxides as binder or carrier, however, since alumina and the like have acidity, which can affect the selectivity of main product in olefin epoxidation and the like, therefore, the molding of TS-1 mostly uses silica as binder (CN102441429A), but the strength using silica is generally not as good as alumina (CN102259023A). For example, patent CN101371989 discloses a titanium silicalite catalyst and its preparation method and application. Its technical features are that the titanium silicalite with MFI structure is mixed with nano-alumina, aluminum sol, pore-forming agent and adjuvant, and a catalyst with high mechanical strength is prepared by extrusion molding method.

[0008] Patents CN102049304A, CN102049305A and CN102451763A all disclose a preparation method of a titanium silicalite composite catalyst. The method is that titanium silicalite powder is mixed with polymer monomer and pore-forming agent, and then polymerization reaction is carried out in the presence of initiator, and then the obtained block solid catalyst is crushed, and then is added into halogenated hydrocarbon for swelling, and then solvent extraction is used to obtain the molded composite catalyst. The obtained catalyst solves the problem of difficult separation of titanium silicalite catalyst powder and reaction liquid, and improves the reaction efficiency.

[0009] Patent CN102614911A discloses a molding method of titanium silicalite. After hydrothermal synthesis of titanium silicalite is crystallized, separation, water washing and calcination are omitted, and instead, matrix material, binder, peptizing agent, polyethylene glycol or sesbania powder is directly added as pore-expanding agent, and then is sprayed and molded after beating, and then the molded microspheres are calcined to remove the template agent, and then large-particle molded titanium silicalite particles are obtained.

[0010] Although researchers have carried out extensive research on the extrusion molding method of TS-1 and achieved fruitful results, the research on the secondary utilization of waste powder formed in the crushing process after extrusion molding is still less. It is estimated that about 50 kg of waste powder is produced for every 1 t of finished product strip-shaped catalyst. If this part of waste powder cannot be well utilized, it will seriously affect the cost of the catalyst, and it is also a great waste of raw materials. If the waste powder is directly used for secondary extrusion in the same way as TS-1, the performance of the strip-shaped catalyst obtained will be obviously reduced, and the mechanical strength will also be lower. Therefore, it is necessary to further study the secondary molding method of waste powder, and further promote the industrialization of TS-1 catalytic green oxidation process.

[0011] In addition, a large amount of mother liquor is produced in the hydrothermal synthesis of titanium silicalite molecular sieve, i.e. the liquid obtained after the solid-liquid separation of the suspension after the crystallization of the molecular sieve. For each ton of titanium silicalite molecular sieve, 15-20 tons of mother liquor is produced. Therefore, the treatment and recycling of the mother liquor is of great significance to the industrialization of titanium silicalite molecular sieve. SUMMARY

[0012] The present application aims to provide a secondary forming method of extruded strip-shaped titanium silicalite molecular sieve TS-1 waste powder, so as to solve the utilization problem of a large amount of waste powder formed in the preparation of strip-shaped TS-1 in the prior art. The present application uses TS-1 waste powder and TS-1 mother liquor as raw materials to prepare titanium silicalite molecular sieve TS-1 catalyst, which recycles resources, saves costs and avoids waste of resources.

[0013] In order to achieve the above-mentioned purpose, the present application provides a method for secondary extrusion of titanium silicalite molecular sieve TS-1 waste powder, comprising the following steps:

[0014] S1, grinding titanium silicalite molecular sieve TS-1 waste powder to 60 mesh or less, adding a pore former and mixing, then adding TS-1 mother liquor and kneading to obtain a cohesive block;

[0015] S2, extruding the cohesive block into a wet base strip to obtain a wet base strip-shaped catalyst;

[0016] S3, drying the wet base strip-shaped catalyst to obtain a dry base strip-shaped catalyst;

[0017] S4, calcining the dry base strip-shaped catalyst to obtain an extruded strip-shaped catalyst.

[0018] In the preferred scheme, in step S1, the pore former is selected from one or more of sesbania powder, activated carbon, cellulose, starch and gelatin.

[0019] In the preferred scheme, in step S1, the mass ratio of the titanium silicalite molecular sieve TS-1 waste powder, the pore former and the TS-1 mother liquor is 100:(2-20):(20-200).

[0020] In the preferred scheme, in step S1, the TS-1 mother liquor comprises SiO2, TiO2, tetrapropylammonium ion, hydroxide ion and water.

[0021] In some embodiments of the present application, the TS-1 mother liquor is obtained by filtering or centrifuging the suspension containing TS-1 after the crystallization is completed in the hydrothermal synthesis of TS-1 molecular sieve, and then separating the solid and liquid to obtain the liquid part as the TS-1 mother liquor. A large amount of TS-1 waste powder is generated in the primary extrusion forming, which causes resource waste. In the present application, TS-1 waste powder and TS-1 mother liquor are used as raw materials to prepare titanium silicalite TS-1 catalyst. In the process of hydrothermal synthesis of titanium silicalite, about 15-20 tons of TS-1 suspension is generated per ton of titanium silicalite. The TS-1 suspension is centrifuged or filtered, and the liquid part is taken as the TS-1 mother liquor for the preparation process of the present application. The resource is recycled, the cost is saved, and the waste of resources is avoided, which is of great significance to the industrialization of titanium silicalite.

[0022] The hydrothermal method comprises mixing a silicon source, a titanium source, a template agent, an alkali source and water, and then performing high-temperature crystallization reaction in a hydrothermal crystallization kettle to obtain a suspension containing TS-1.

[0023] The silicon source is one or more of ethyl silicate, silica sol, white carbon black and water glass; the titanium source is one or more of titanium sulfate, titanium isopropoxide and titanium trichloride; and the template agent is one or more of tetrapropylammonium hydroxide and tetrapropylammonium bromide.

[0024] In a preferred embodiment, the mass fraction of SiO2 is 0.1%-2%, the mass fraction of TiO2 is 0.01%-0.1%, the mass fraction of tetrapropylammonium ion is 0.2%-5.0%, and the mass fraction of hydroxyl ion is 0.5%-5.0%.

[0025] In a preferred embodiment, in step S3, the drying temperature is 20-50℃, and the drying time is 24-36h.

[0026] In a preferred embodiment, in step S4, the calcination temperature is 300-600℃, and the calcination time is 3-6h.

[0027] In a preferred embodiment, in step S2, the adhesive block obtained in step S1 is loaded into an extruder, and then extruded into a wet base strip-shaped catalyst at a speed of 20-1000g / min under a pressure of 0.5-2.0MPa.

[0028] The present application has the following advantages:

[0029] 1. The TS-1 catalyst prepared by the method of the present application can be used in various oxidation reactions such as olefin epoxidation, aromatic hydroxylation, ketone ammoxidation, alkane selective oxidation, oxidative desulfurization and alcohol oxidation, which realizes the secondary utilization of waste powder and TS-1 mother liquor, reduces the preparation cost of the catalyst, and reduces environmental pollution.

[0030] 2、The TS-1 catalyst prepared by the method has high mechanical strength, is similar to the TS-1 once extruded into a strip, and is 1.5 times the strength of the conventional TS-1 twice extruded into a strip. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the X-ray diffraction pattern of TS-1F in the embodiment 3 of the application.

[0032] Figure 2 is the ultraviolet-visible diffuse reflectance spectrum of TS-1F in the embodiment 3 of the application. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the embodiments and the drawings. For any skilled person in the art, many possible changes and modifications or equivalent embodiments of the above disclosed technical content can be made to the technical solution of the application without departing from the scope of the technical solution of the application. Therefore, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the application, which does not depart from the content of the technical solution of the application, should still belong to the protection scope of the technical solution of the application. The raw materials used in the application are commercially available if not otherwise specified.

[0034] A method for twice extruding a strip of titanium silicalite TS-1 waste powder, comprising the following steps:

[0035] S1, grinding the titanium silicalite TS-1 waste powder to 60 mesh or less, sequentially adding a pore former, a TS-1 mother liquor, and mixing uniformly to obtain a wet adhesive block body for extruding a strip;

[0036] The mass ratio of the TS-1 waste powder to the pore former and the TS-1 mother liquor is 100:(2-20):(20-200).

[0037] The TS-1 waste powder is a small particle smaller than the required particle size of industrial use, which is broken in the extruding process of the strip, and mainly consists of TS-1 molecular sieve and a binder, and the mass ratio of the two (TS-1 molecular sieve and the binder) is 100:(5-40).

[0038] The pore former is one or more of sesbania powder, activated carbon, cellulose, starch and gelatin.

[0039] The TS-1 mother liquor is the liquid left after the suspension liquid containing TS-1 is separated by filtration or centrifugation after the crystallization is completed in the hydrothermal synthesis of TS-1 molecular sieve.

[0040] The hydrothermal synthesis of TS-1 molecular sieve is to mix a silicon source, a titanium source, a template agent, an alkali source and water in a certain proportion, to crystallize in a hydrothermal crystallization kettle at a high temperature for a certain time, and to obtain a suspension containing TS-1.

[0041] The silicon source is one or more of ethyl silicate, silica sol, white carbon black and water glass; the titanium source is one or more of titanium sulfate, titanium isopropoxide and titanium trichloride; and the template agent is one or more of tetrapropylammonium hydroxide and tetrapropylammonium bromide.

[0042] S2, the agglomerated block obtained in S1 is loaded into an extruder, and is extruded into a wet base strip-shaped catalyst at a speed of 20-1000 g / min under a pressure of 0.5-2.0 MPa;

[0043] S3, the wet base strip-shaped catalyst obtained in S2 is dried in air at 20-50℃ for 24-36 h to obtain a dry base strip-shaped catalyst;

[0044] S4, the dry base strip-shaped catalyst obtained in S3 is calcined in air at 300-600℃ for 3-6 h to obtain an extruded catalyst;

[0045] The TS-1 mother liquor contains 0.1%-2% of SiO2, 0.01%-0.1% of TiO2, 0.2%-5.0% of tetrapropylammonium ions, 0.5%-5.0% of hydroxide ions and other components mainly being water.

[0046] The experimental conditions or steps in the examples are operated according to the above-mentioned experimental conditions or steps unless otherwise specified.

[0047] Example 1

[0048] 40 g of titanium silicate molecular sieve TS-1 waste powder is ground to 60 mesh or less, mixed with 1 g of sesbania powder, and then kneaded with 18 g of deionized water and 6 g of TS-1 mother liquor. After extrusion molding, air drying, and shearing into 1-2 mm long, a shaped catalyst is obtained by calcining at 540℃ for 6 h, which is numbered as TS-1D.

[0049] Example 2

[0050] 40 g of titanium silicate molecular sieve TS-1 waste powder is ground to 60 mesh or less, mixed with 1 g of sesbania powder, and then kneaded with 12 g of deionized water and 12 g of TS-1 mother liquor. After extrusion molding, air drying, and shearing into 1-2 mm long, a shaped catalyst is obtained by calcining at 540℃ for 6 h, which is numbered as TS-1E.

[0051] Example 3

[0052] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 1 g of sesbania powder, add 24 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1F.

[0053] As Figure 1 shown is the X-ray diffraction pattern of TS-1F. It can be seen from Figure 1 that the sample has characteristic diffraction peaks of typical MFI structure, and the peak intensity is strong, indicating that the secondary molding process does not destroy the framework structure of TS-1. As Figure 2 shown is the UV-Vis diffuse reflectance spectrum of TS-1F, Figure 2 the absorption peaks near 220 nm and 330 nm are attributed to the characteristic peaks of four-coordinated titanium and anatase TiO2 respectively, indicating that the main form of titanium is four-coordinated titanium.

[0054] Example 4

[0055] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 1.5 g of sesbania powder, add 24 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1G.

[0056] Example 5

[0057] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 2 g of sesbania powder, add 24 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1H.

[0058] Example 6

[0059] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 2.5 g of sesbania powder, add 24 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1I.

[0060] Example 7

[0061] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 3 g of sesbania powder, add 24 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1J.

[0062] Example 8

[0063] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 3 g of sesbania powder, add 25 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1K.

[0064] Example 9

[0065] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 3 g of sesbania powder, add 25 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1K.

[0066] Example 10

[0067] Take 40 g of titanium silicalite TS-1 waste powder to 60 mesh, mix with 3 g of sesbania powder, add 25 g of TS-1 mother liquor, knead, extrude into strips, dry, cut into 1-2 mm long, calcine at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1K.

[0068] Comparative Example 1

[0069] According to the method provided in the literature "Catalysis" (2001, 22 (6): 513-514), powder TS-1 and its mother liquor were prepared. 50 g of tetraethyl orthosilicate was added to a three-necked flask with a jacket, 45 g of TPAOH aqueous solution and 40 g of water were added under magnetic stirring at 25℃, and the tetraethyl orthosilicate was hydrolyzed for 90 min; 15 g of isopropyl alcohol was added to 2 g of tetrabutyl titanate, and 17 g of TPAOH solution and 20 g of water were added in turn under stirring, and the tetrabutyl titanate hydrolysate was obtained by hydrolyzing at room temperature for 30 min. The silicon ester and the titanium ester hydrolysate were mixed, and the alcohol was removed at 85℃ for 6h. The obtained clear solution was loaded into a crystallization kettle, and crystallization was carried out at 170℃ for 24h. The obtained suspension was centrifuged, and the solid product was washed, dried and calcined at 540℃ for 5h to obtain TS-1, which was numbered as TS-1A. The liquid product separated by centrifugation was the TS-1 mother liquor, which was used in the secondary shaping process in Examples 1-10 above.

[0070] Comparative Example 2

[0071] According to the method provided in Example 6 of patent CN103464197A, 20 g of titanium silicalite TS-1 powder prepared according to Comparative Example 1 of the present application, 1.66 g of SiO2 and 1.0 g of sesbania powder were mixed and ground uniformly, 16.2 g of silica sol and 0.7 g of liquid paraffin were added and kneaded, extruded into strips, dried, cut into 1-2 mm long, calcined at 540℃ for 6h to obtain a shaped catalyst, which is numbered as TS-1B.

[0072] Comparative Example 3

[0073] According to the method provided in Example 6 of the patent CN103464197A, 20 g of titanium silicalite TS-1 waste powder ground to 60 mesh or less, 1.66 g of SiO2 and 1.0 g of sesbania powder were uniformly mixed and ground, 16.2 g of silica sol and 0.7 g of liquid paraffin were added and kneaded, extruded into strips, air-dried, cut into 1-2 mm long cylinders, and calcined at 540°C for 6 h to obtain a shaped catalyst, which is denoted as TS-1C.

[0074] Application Example 1

[0075] The mechanical strength of some of the samples prepared in the comparative examples and the examples was measured using a DL II type intelligent particle strength tester from Dalian Institute of Chemical Physics. The strip-shaped catalyst with a diameter of 2 mm was cut into a cylinder with a height of 2 mm. The radial and axial strengths were each measured 42 times, and the average was taken after removing the maximum and minimum values. The results are shown in Table 1. The extrusion molding can make the catalyst have a suitable shape, size and good mechanical strength. The axial and radial strengths of the shaped catalyst prepared by the secondary extrusion method provided in the present application are similar to those of TS-1B prepared by the primary extrusion method, and are about 1.5 times higher than those of TS-1C prepared by the conventional secondary extrusion method, indicating that the catalyst prepared by the method of the present application has a significantly better ability to resist damage to the catalyst caused by loading, temperature rising, reaction and pressure drop than TS-1C prepared by the conventional secondary extrusion method.

[0076] Table 1 Mechanical strength of some of the samples prepared in the comparative examples and the examples

[0077] Sample Radial strength (N / cm 2 )]]> Axial strength (N / cm 2 )]]> TS-1B 101.4 701.6 TS-1C 63.7 429.2 TS-1D 93.4 675.8 TS-1E 94.6 667.5 TS-1F 92.8 672.7

[0078] Application Example 2

[0079] The catalytic performance of the catalyst was evaluated by preparing propylene oxide through propylene epoxidation. 0.2 g of catalyst powder and 34 mL of H2O2 / CH3OH solution were added to a 400 mL stainless steel batch reactor. Propylene gas was introduced, and the reaction pressure was maintained at 0.5 MPa. The constant temperature water bath and magnetic stirring were turned on, and the reactants were allowed to react at 40°C for 1 h. After the reaction was completed, the sample was analyzed. Agilent GC-7890B gas chromatography was used to detect the composition of the reaction products. Indirect iodometric method was used to determine the content of residual H2O2. In the propylene epoxidation reaction, propylene oxide (PO) is the target product, 1,2-propanediol (PG) and monomethyl ether (MME) are by-products. X(H2O2) is the hydrogen peroxide conversion rate, S(PO) is the propylene oxide selectivity, and U(H2O2) is the effective utilization rate of hydrogen peroxide, which are calculated by the following formulas:

[0080] X(H2O2) = 1 - n(H2O2) / n0(H2O2)

[0081] S(PO) = n(PO) / (n(PO) + n(MME) + n(PG))

[0082] U(H2O2) = (n(PO) + n(MME) + n(PG)) / (n0(H2O2) x X(H2O2))

[0083] Wherein, n0(H2O2) and n((H2O2)) represent the amount of substance of hydrogen peroxide before and after the reaction, n(PO), n(MME) and n(PG) represent the amount of substance of PO, MME and PG.

[0084] Table 2. Catalytic propylene epoxidation performance of some samples prepared by the comparative examples and the examples

[0085] Sample X (H2O2) / % S(PO) / % [CAT] / % U(H2O2) / % TS-1B 70.1 94.9 85.4 TS-1C 60.7 97.6 84.0 TS-1D 65.1 93.3 87.8 TS-1E 66.6 93.8 87.6 TS-1F 65.9 94.1 86.6

[0086] As shown in Table 2, the strip-shaped TS-1 catalyst prepared by the secondary extrusion forming method provided by the application has lower propylene epoxidation activity (hydrogen peroxide conversion rate) than the primary extrusion catalyst TS-1B, but higher than the conventional secondary extrusion catalyst TS-1C. The propylene oxide selectivity of the secondary extrusion catalyst provided by the application is similar to that of the primary extrusion catalyst, and the effective utilization rate of hydrogen peroxide is slightly higher than that of the primary extrusion catalyst.

[0087] The application discloses a secondary forming method of extrusion forming titanium silicate molecular sieve TS-1 waste powder. The TS-1 waste powder is ground to below 60 mesh, a pore-forming agent and a TS-1 mother liquor are sequentially added, and the mixture is uniformly mixed to obtain a wet adhesion block body for extrusion forming; the adhesion block body is loaded into an extruder to be extruded into a wet base strip-shaped catalyst; the wet base strip-shaped catalyst is dried in air at 20-50 DEG C for 24-36 h to obtain a dry base strip-shaped catalyst; and the dry base strip-shaped catalyst is calcined in air at 300-600 DEG C for 3-6 h to obtain an extrusion forming catalyst. The TS-1 catalyst prepared by the method can be used in various oxidation reactions such as olefin epoxidation, aromatic hydroxylation, ketone ammoxidation, alkane selective oxidation, oxidative desulfurization and alcohol oxidation, realizes secondary utilization of the waste powder and the mother liquor, reduces the preparation cost of the catalyst and reduces environmental pollution.

[0088] The above merely provides the preferred embodiments of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical scheme and the inventive concept of the application within the technical scope disclosed by the application, which should be covered by the protection scope of the application.

Claims

1. A method for secondary molding of titanium silicalite TS-1 waste powder, characterized in that, The method comprises the following steps: S1, grinding titanium silicalite TS-1 waste powder to 60 mesh or less, adding a pore-forming agent, mixing, then adding TS-1 mother liquor, and kneading to obtain a cohesive block; The TS-1 mother liquor is obtained by filtering or centrifuging a suspension containing TS-1 after hydrothermal synthesis of TS-1, solid-liquid separation, and taking the liquid part; S2, extruding the cohesive block into a wet base strip to obtain a wet base strip catalyst; S3, drying the wet base strip catalyst to obtain a dry base strip catalyst; S4, calcining the dry base strip catalyst to obtain an extruded strip catalyst.

2. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, In step S1, the pore-forming agent is selected from one or more of sesbania powder, activated carbon, cellulose, starch, and gelatin.

3. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, In step S1, the mass ratio of the titanium silicalite TS-1 waste powder, the pore-forming agent, and the TS-1 mother liquor is 100:(2-20):(20-200).

4. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, In step S1, the TS-1 mother liquor comprises SiO2, TiO2, tetrapropylammonium ions, hydroxide ions, and water.

5. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 4, characterized in that, The mass fraction of SiO2 is 0.1%-2%, the mass fraction of TiO2 is 0.01%-0.1%, the mass fraction of tetrapropylammonium ions is 0.2%-5.0%, and the mass fraction of hydroxide ions is 0.5%-5.0%.

6. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, In step S3, the drying temperature is 20-50°C, and the time is 24-36h.

7. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, In step S4, the calcination temperature is 300-600°C, and the time is 3-6h.

8. The method for secondary molding of titanium silicalite TS-1 waste powder according to claim 1, characterized in that, The operating conditions of step S2 are as follows: the cohesive block obtained in S1 is loaded into an extruder, extruded into a wet base strip catalyst at a speed of 20-1000g / min under a pressure of 0.5-2.0MPa.

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