A method for preparing type A molecular sieve from FCC catalyst waste rubber residues

Abstract

The present application belongs to the field of solid waste recycling, and particularly relates to a method for preparing A-type molecular sieve from FCC catalyst waste rubber residue. The present application does not need any high-temperature or alkali fusion activation, and only needs to dry, crush and screen the FCC catalyst waste rubber residue to use it as a raw material for synthesizing A-type molecular sieve. The A-type molecular sieve is directly hydrothermally synthesized from solid waste, does not need to add an organic template agent, and can be successfully synthesized in a short time. Therefore, the present application has great research significance in the aspects of green environmental protection, comprehensive utilization of solid waste, reduction of molecular sieve preparation cost, widening of the field of molecular sieve synthesis and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of solid waste recycling, and particularly relates to a method for preparing A-type molecular sieve from FCC catalyst waste sludge. BACKGROUND

[0002] FCC catalyst is one of the core processes of petroleum refining. China is the largest market for molecular sieve catalysts, so a large amount of FCC catalyst waste sludge will be generated. During the manufacturing process of FCC catalyst, a large amount of wastewater containing a high amount of suspended solids will be generated. In order to ensure that the discharged wastewater meets the standards, the wastewater is treated by sedimentation, residue cutting and filtration before being discharged, thus a certain amount of solid waste, i.e. FCC catalyst waste sludge, will be generated. Characterization analysis shows that the main components of FCC catalyst waste sludge are silicon and aluminum oxides (accounting for about 60% to 75% of the total component mass fraction in terms of Al2O3 and SiO2). For enterprises that produce FCC catalysts using silicon and aluminum as main raw materials, if a cost-effective and industrially feasible method, such as synthesizing A-type molecular sieve, is used to recycle and utilize the waste, it can not only greatly reduce the environmental pollution caused by solid waste, but also help reduce production costs and improve economic benefits. It has great research significance in terms of green environmental protection, comprehensive utilization of solid waste, reduction of A-type molecular sieve preparation costs, and expansion of the field of A-type molecular sieve synthesis.

[0003] A-type molecular sieve (LTA) is an alkali metal aluminosilicate mineral with a regular pore system, which is composed of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron by sharing oxygen atoms. It is a low-silicon zeolite with three-dimensional 8-membered vertical pore channels and cubic crystal system. Due to its special crystal structure, A-type molecular sieve has high porosity and high ion exchange performance. After potassium ion and sodium ion exchange, A-type molecular sieve is called 3A and 5A type molecular sieve respectively. Due to its pore characteristics and high ion exchange performance, A-type molecular sieve is one of the most widely used molecular sieves. It is mainly used as a major component of detergents, for drying and purifying gases, and for separating nitrogen and oxygen in air. So far, there has been no report on the synthesis of A-type molecular sieve using FCC catalyst waste sludge as raw material. SUMMARY

[0004] The present application provides a method for preparing A-type molecular sieve using FCC catalyst waste sludge as raw material. The method is green, fast and efficient. Specifically, the method comprises the following steps:

[0005] (1) The FCC catalyst waste sludge is dried in a blast drying oven at 100-130℃ for 24-72h to remove the water therein, and then crushed and sieved through a 60 mesh sieve.

[0006] (2) Dissolve sodium hydroxide in deionized water and stir at room temperature for 0-20 min; then add the FCC catalyst waste rubber residue treated in step (1) as the total silicon source and part of the aluminum source of the A-type molecular sieve, and stir at room temperature for 0.5-2 h;

[0007] (3) Based on SiO2 in the FCC catalyst waste rubber residue, add an aluminum source to form an A-type molecular sieve and stir uniformly in the silicon-aluminum system in step (2), and then stir and age at room temperature for 0-16 h.

[0008] In the synthesis system, the initial molar ratio of the A-type molecular sieve mother liquor is: Na2O:Al2O3:SiO2:H2O = 1.9-3.8:1:1.5-3.6:68-188.

[0009] (4) Finally, the mixed system in step (3) is hydrothermally crystallized at 70-110°C for 1-4 h, centrifugally washed, and dried at 80-120°C for 8-12 h to obtain the A-type molecular sieve.

[0010] Further, in step (3), the aluminum source is one of pure aluminum powder, sodium metaaluminate, and sodium aluminate.

[0011] The A-type molecular sieve prepared by the above method is applied to metal ion adsorption, for example, Cd 2+ adsorption, and the steps are as follows: mix the A-type molecular sieve with Cd 2+ waste water, stir at room temperature for 0-12 h, and separate the solid particles and liquid products by centrifugation after the reaction is completed.

[0012] The beneficial effects of the present application include but are not limited to:

[0013] (1) The present application only needs to dry, crush, and sieve the FCC catalyst waste rubber residue, without any high-temperature or alkali fusion activation, so that it can be directly used as a raw material for synthesizing the A-type molecular sieve, which not only reduces resource waste and saves energy, but also provides a new method for preparing A-type molecular sieves from industrial solid waste.

[0014] (2) The present application uses the simply treated FCC catalyst waste rubber residue as the total silicon source and part of the aluminum source, without a high-cost template, and can be synthesized at low temperature for a short time, with a green, fast, and efficient synthesis method.

[0015] (3) The present application investigates and optimizes the crystallization conditions such as crystallization temperature, time, silicon-aluminum ratio, alkalinity ratio, and water-silicon ratio to obtain suitable synthesis conditions. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 XRD patterns of the molecular sieves prepared in Examples 1-12 and Comparative Example 1. DETAILED DESCRIPTION

[0017] The present application is further illustrated by the following examples, which are merely illustrative and should not be construed as limiting the scope of the present application.

[0018] The FCC catalyst waste residue used in the embodiments of the present application is analyzed as follows: the FCC catalyst waste residue is placed in an oven for drying to remove a large amount of water; the main components in the residue are analyzed by XRF characterization, and the measured oxide mass fraction of SiO2 in the residue is 51.8%, the measured oxide mass fraction of Al2O3 in the residue is 14.3%, the measured oxide mass fraction of Na2O in the residue is 9.7%, the measured oxide mass fraction of La2O3 in the residue is 4.3%, the measured oxide mass fraction of CeO2 in the residue is 9.3%, the measured oxide mass fraction of SO3 in the residue is 4.2%, the measured oxide mass fraction of CaO in the residue is 1.4%, the measured oxide mass fraction of P2O5 in the residue is 1.3%, the measured oxide mass fraction of MgO in the residue is 1.1%, and the remaining impurities account for less than 5.0%, which can be ignored.

[0019] Example 1

[0020] (1) The FCC catalyst waste residue without any treatment is placed in a forced air drying oven at 120°C for drying for 48h to remove water therein, and then is crushed by a high-speed crusher and treated by passing through a 60-mesh sieve for standby;

[0021] (2) At room temperature, 2.4g of sodium hydroxide is dissolved in 31.0mL of deionized water and stirred for 10min, then 3.0g of the pretreated FCC catalyst waste residue is added to the system, and stirred at room temperature for 2h, finally 1.9g of sodium metaaluminate (>80wt%) is added under vigorous stirring, and stirred at room temperature for 4h for aging;

[0022] (3) The mixed system is transferred into a 50mL stainless steel crystallization kettle, then placed in a forced air drying oven at 90°C for crystallization for 2h, after the crystallization is completed and the system is cooled to room temperature, the sample is centrifuged, washed, suction filtered, and dried at 100°C for 10h to obtain the A-type molecular sieve.

[0023] Example 2

[0024] (1) The same as step (1) in Example 1;

[0025] (2) The same as step (2) in Example 1;

[0026] (3) The mixed system is transferred into a 50mL stainless steel crystallization kettle, then placed in a forced air drying oven at 80°C for crystallization for 2h, after the crystallization is completed and the system is cooled to room temperature, the sample is centrifuged, washed, suction filtered, and dried at 100°C for 10h to obtain the A-type molecular sieve.

[0027] Example 3

[0028] (1) The same as step (1) in Example 1;

[0029] (2) Same as step (2) in Example 1 ;

[0030] (3) The mixed system was transferred into a 50 mL stainless steel crystallization kettle, then placed in a blast drying oven at 100°C for crystallization for 2 h. After the crystallization was completed and the system was cooled to room temperature, the sample was centrifuged, washed, suction filtered, and dried at 100°C for 10 h to obtain the A-type molecular sieve.

[0031] Example 4

[0032] (1) Same as step (1) in Example 1 ;

[0033] (2) Same as step (2) in Example 1 ;

[0034] (3) The mixed system was transferred into a 50 mL stainless steel crystallization kettle, then placed in a blast drying oven at 90°C for crystallization for 1 h. After the crystallization was completed and the system was cooled to room temperature, the sample was centrifuged, washed, suction filtered, and dried at 100°C for 10 h to obtain the A-type molecular sieve.

[0035] Example 5

[0036] (1) Same as step (1) in Example 1 ;

[0037] (2) Same as step (2) in Example 1 ;

[0038] (3) The mixed system was transferred into a 50 mL stainless steel crystallization kettle, then placed in a blast drying oven at 90°C for crystallization for 4 h. After the crystallization was completed and the system was cooled to room temperature, the sample was centrifuged, washed, suction filtered, and dried at 100°C for 10 h to obtain the A-type molecular sieve.

[0039] Example 6

[0040] (1) Same as step (1) in Example 1 ;

[0041] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min. Then 3.0 g of pretreated FCC catalyst waste residue was added to the system, and stirred at room temperature for 2 h. Finally, 1.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring, and stirred and aged at room temperature for 4 h;

[0042] (3) Same as step (3) in Example 1.

[0043] Example 7

[0044] (1) Same as step (1) in Example 1 ;

[0045] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 23.7 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst spent gum was added to the system and stirred at room temperature for 2 h, finally 1.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and stirred at room temperature for 4 h of aging;

[0046] (3) Same as step (3) in Example 1.

[0047] Example 8

[0048] (1) Same as step (1) in Example 1;

[0049] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 38.2 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst spent gum was added to the system and stirred at room temperature for 2 h, finally 1.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and stirred at room temperature for 4 h of aging;

[0050] (3) Same as step (3) in Example 1.

[0051] Example 9

[0052] (1) Same as step (1) in Example 1;

[0053] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst spent gum was added to the system and stirred at room temperature for 2 h, finally 0.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and stirred at room temperature for 4 h of aging;

[0054] (3) Same as step (3) in Example 1.

[0055] Example 10

[0056] (1) Same as step (1) in Example 1;

[0057] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst spent gum was added to the system and stirred at room temperature for 2 h, finally 1.3 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and stirred at room temperature for 4 h of aging;

[0058] (3) Same as step (3) in Example 1.

[0059] Example 11

[0060] (1) Same as step (1) in Example 1;

[0061] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst waste rubber residue was added to the system and stirred at room temperature for 2 h, finally 1.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and aged at room temperature for 8 h;

[0062] (3) The same as step (3) in Example 1.

[0063] Example 12

[0064] (1) The same as step (1) in Example 1;

[0065] (2) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min, then 3.0 g of pretreated FCC catalyst waste rubber residue was added to the system and stirred at room temperature for 2 h, finally 1.9 g of sodium metaaluminate (>80 wt%) was added under vigorous stirring and aged at 40°C for 8 h;

[0066] (3) The same as step (3) in Example 1.

[0067] Comparative Example 1

[0068] (1) At room temperature, 2.0 g of sodium hydroxide was dissolved in 31.0 mL of deionized water and stirred for 10 min, then 2.8 g of sodium metaaluminate (>80 wt%) was added to the system and stirred for 20 min, finally 1.5564 g of fumed silica powder was added and aged at 40°C for 8 h;

[0069] (2) The mixed system was transferred into a 50 mL stainless steel crystallization kettle, then placed in a forced air drying oven at 90°C for 2 h of crystallization, after the crystallization was completed, the system was reduced to room temperature, the sample was centrifuged, washed, suction filtered, and dried at 100°C for 10 h to obtain the A-type molecular sieve.

[0070] Figure 1 The XRD pattern of the FCC catalyst waste rubber residue-based molecular sieve, as can be seen from the figure, the above-mentioned 12 examples and 1 comparative example all have 11 obvious characteristic diffraction peaks at 2θ = 7.20, 10.18, 12.46, 16.10, 20.42, 21.66, 23.98, 26.10, 27.12, 29.94, 34.16, which are respectively attributed to different crystal faces of A-type molecular sieve, which shows that the A-type molecular sieve is successfully synthesized by using the FCC catalyst waste rubber residue in the present patent

[0071] Table 1 is the Cd 2+ adsorption performance test results. Cd 2+The adsorption performance test method is: 0.04 g of A-type molecular sieve and 50 mL of 100 mg / L Cd(NO3)2·4H2O are respectively loaded into a 50 mL conical flask, and magnetically stirred at room temperature for 3 h. After the reaction, the solid particles and liquid products are separated by centrifugation, and the Cd 2+ concentration is analyzed by ultraviolet-visible spectrophotometer. The adsorption rate η (%) and adsorption capacity Q e (mg / g) of the A-type molecular sieve are calculated according to formulas (1) and (2).

[0072] η = (C0-C e ) / C e × 100% (1)

[0073] Q e = (C0-C e ) × V / m (2)

[0074] In the formula: C0 is the initial concentration of heavy metal ions in the wastewater solution before adsorption experiment, mg / L

[0075] C e is the concentration of heavy metal ions in the wastewater solution after adsorption experiment, mg / L

[0076] V is the volume of Cd 2+ wastewater solution, L

[0077] m is the amount of adsorbent, g.

[0078] Table 1 FCC catalyst waste rubber residue-based molecular sieve adsorption performance of Cd 2+

[0079]

[0080] Table 1 shows that the removal rate and adsorption capacity of A-type molecular sieve for Cd 2+ are high, indicating that the A-type molecular sieve has good adsorption performance.

[0081] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.​

Claims

1. A method for preparing type A molecular sieves from FCC catalyst waste residue, characterized in that, Includes the following steps: (1) Dry the waste glue residue of FCC catalyst, and then crush and screen it; (2) Dissolve sodium hydroxide in deionized water; then add the FCC catalyst waste residue treated in step (1) as the entire silicon source and part of the aluminum source for type A molecular sieve, and stir at room temperature; (3) Using SiO2 in the waste residue of FCC catalyst as a reference, add aluminum source and stir evenly to the silicon-aluminum system in step (2), and then stir and age at room temperature; The initial molar ratio of the mother liquor for synthesizing type A molecular sieves was: Na2O:Al2O3:SiO2:H2O = 1.9-3.8:1:1.5-3.6:68-188; (4) After crystallizing and centrifuging the mixed system described in step (3), dry it to obtain type A molecular sieve; the crystallization temperature is 70-110 ℃ and the time is 1-2 h.

2. The method for preparing type A molecular sieves from FCC catalyst waste residue according to claim 1, characterized in that, In step (1), the drying temperature of the FCC catalyst waste gum residue is 100-130 ℃ and the time is 24-72 h; the screening process is to pass through a 60-mesh sieve.

3. The method for preparing type A molecular sieves from FCC catalyst waste residue according to claim 1, characterized in that, In step (2), the stirring time is 0.5-2 h.

4. The method for preparing type A molecular sieves from FCC catalyst waste residue according to claim 1, characterized in that, In step (3), the aluminum source is one of pure aluminum powder, sodium aluminate, and sodium aluminate.

5. The method for preparing type A molecular sieves from FCC catalyst waste residue according to claim 1, characterized in that, In step (3), the stirring and aging time is 0-16 h.

6. A type A molecular sieve synthesized by the method according to any one of claims 1-5.

7. An application of the type A molecular sieve according to claim 6 in the adsorption of metal ions.

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