CN113880105A - Treatment method of NaY molecular sieve waste liquid, application of NaY molecular sieve waste liquid and NaY molecular sieve - Google Patents
Treatment method of NaY molecular sieve waste liquid, application of NaY molecular sieve waste liquid and NaY molecular sieve Download PDFInfo
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Abstract
The invention relates to the field of preparation of NaY molecular sieves, and discloses a treatment method of NaY molecular sieve waste liquid, application of the treatment method and a NaY molecular sieve prepared by the treatment method. The method comprises the following steps: 1) carrying out solid-liquid separation on the NaY molecular sieve waste liquid to ensure that the content of suspended matters in a liquid phase obtained by the solid-liquid separation is below 300 mg/L; 2) and contacting the liquid phase with an aluminum salt to prepare the silica-alumina gel, wherein the NaY molecular sieve waste liquid contains NaY molecular sieve mother liquid and/or washing filtrate. The method can not only improve the utilization rate of silicon, but also ensure that the prepared NaY molecular sieve has low P-type mixed crystal content and excellent quality.
Description
Technical Field
The invention relates to the field of preparation of NaY molecular sieves, in particular to a treatment method of NaY molecular sieve waste liquid, application of the treatment method and a NaY molecular sieve prepared by the treatment method.
Background
The Y-type molecular sieve is a typical microporous molecular sieve, which is used as an active component of a catalyst and widely applied to the refining and processing processes of petroleum, in particular to the catalytic cracking process and the hydrocracking process. The preparation of the Y-type molecular sieve generally comprises two steps of synthesis of the NaY molecular sieve and post-modification of the NaY molecular sieve, wherein the synthesis of the NaY molecular sieve plays a decisive role in building a basic framework structure of the Y-type molecular sieve, so that the Y-type molecular sieve is widely concerned and researched up to now.
CN108264070A discloses a recycling method of NaY crystallization mother liquor and/or filtrate. The NaY crystallization mother liquor containing P type mixed crystals or the NaY crystallization mother liquor which has crystallization time more than 50 hours and crystallinity lower than 50 percent and does not have NaP crystal phase in a phase spectrogram is directly used for preparing a porous material, and the obtained porous material takes pseudo-boehmite as a main crystal phase structure.
CN107662927A discloses a method for preparing a high-activity long-acting guiding agent by using a silicon-aluminum molecular sieve crystallization mother liquor to recycle the crystallization mother liquor. Firstly, collecting crystallization mother liquor of a silicon-aluminum molecular sieve, and carrying out evaporation concentration to improve the solid content of the crystallization mother liquor; under the condition of room temperature, the concentrated mother liquor is used as a whole silicon source and a part of alkali source to prepare a directing agent, then a certain amount of alkali source, an aluminum source and water are added, the mixture is aged for a certain time and then added into reaction gel, and crystallization is carried out according to the conventional synthesis method of the NaY molecular sieve.
The above patents all relate to the recycling of mother liquor in the preparation process of the NaY molecular sieve, but the mother liquor in the actual industrial production can not be completely recycled in a NaY molecular sieve synthesis system, and the prepared NaY molecular sieve has P-type zeolite mixed crystals, which affects the performance and quality of the NaY molecular sieve. At present, a large amount of crystallization mother liquor is still discharged outside, which not only causes the waste of silicon, but also pollutes the environment.
Disclosure of Invention
The invention aims to solve the problems of low silicon utilization rate and poor quality of a prepared NaY molecular sieve existing in the process of recycling NaY molecular sieve waste liquid to prepare the NaY molecular sieve in the prior art, and provides a treatment method of the NaY molecular sieve waste liquid.
In order to achieve the above object, the present invention provides a method for treating NaY molecular sieve waste liquid, which is characterized by comprising the following steps:
1) carrying out solid-liquid separation on the NaY molecular sieve waste liquid to ensure that the content of suspended matters in a liquid phase obtained by the solid-liquid separation is below 300 mg/L;
2) contacting the liquid phase with aluminum salt to prepare silica-alumina gel,
wherein the NaY molecular sieve waste liquid contains NaY molecular sieve mother liquid and/or washing filtrate.
Optionally, in step 1), the solid phase obtained by the solid-liquid separation contains NaY molecular sieve.
Preferably, SiO in the NaY molecular sieve waste liquid2The content of (A) is 16-50g/L, Na2The content of O is 15-23g/L, and the content of suspended matters is 800-6000 mg/L; more preferably, SiO is contained in the NaY molecular sieve waste liquid2Has a content of 28-45g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1000-4500 mg/L.
Preferably, in the NaY molecular sieve mother liquor, SiO2Has a content of 36-50g/L, Na2The content of O is 18-23g/L, and the content of suspended matters is 800-2500 mg/L; more preferably, in the NaY molecular sieve mother liquor, SiO2Has a content of 38-45g/L, Na2The content of O is 19-22g/L, and the content of suspended matters is 1000-2000 mg/L.
Preferably, SiO in the NaY molecular sieve washing filtrate2Has a content of 16-35g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1500-6000 mg/L; more preferably, SiO in the NaY molecular sieve washing filtrate2The content of (A) is 25-32g/L, Na2The content of O is 18-20g/L, and the content of suspended matters is 2500-4500 mg/L.
Preferably, in step 2), the aluminum salt is aluminum sulfate and/or aluminum chloride; more preferably, the aluminum salt is aluminum sulfate.
Preferably, in step 2), the molar ratio of the liquid phase, calculated as silica, to the aluminium salt, calculated as elemental aluminium, is from 3 to 8: 1.
preferably, the conditions for preparing the silica alumina gel include: the gelatinizing temperature is 30-60 ℃, and the gelatinizing retention time is 10-20 min; more preferably, the conditions for preparing the silica alumina gel include: the gelling temperature is 45-55 ℃, and the gelling retention time is 13-18 min.
Preferably, the method further comprises: the silica-alumina gel prepared in the step 2) is used for preparing the NaY molecular sieve.
Preferably, when the silica alumina gel prepared in step 2) is used for preparing the NaY molecular sieve, the silicon in the silica alumina gel prepared in step 2) accounts for 0.1-36 wt%, preferably 15-36 wt%, and more preferably 22-36 wt% of the total silicon in the NaY molecular sieve preparation.
The invention provides an application of the treatment method of the NaY molecular sieve waste liquid in treating NaY molecular sieve mother liquid and/or washing filtrate.
The third aspect of the invention provides a NaY molecular sieve prepared by using the silica-alumina gel prepared by the method for treating the NaY molecular sieve waste liquid.
Through the technical scheme, the NaY molecular sieve waste liquid is not required to be settled, and the content of suspended matters can be reduced to a lower level, so that the treatment efficiency of the waste liquid is greatly improved. When the NaY molecular sieve waste liquid is prepared into silica gel and is further recycled to the synthesis of the NaY molecular sieve, NaP mixed crystals of the obtained NaY molecular sieve are reduced, and the quality of the NaY molecular sieve is obviously improved. And the utilization rate of silicon in the whole process can be improved from 85.2% to 99.8%, and the utilization rate is obviously improved.
Drawings
FIG. 1 is an X-ray diffraction pattern of the NaY molecular sieve prepared in example 1;
FIG. 2 is an X-ray diffraction pattern of the NaY molecular sieve prepared in example 2;
FIG. 3 is an X-ray diffraction pattern of the NaY molecular sieve prepared in example 3;
FIG. 4 is an X-ray diffraction pattern of the NaY molecular sieve prepared in example 4;
fig. 5 is an X-ray diffraction pattern of the NaY molecular sieve prepared in comparative example 1.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In the invention, the NaY molecular sieve mother liquor refers to supernatant liquor cut off after crystallization of NaY molecular sieve materials is finished; the NaY molecular sieve washing filtrate is obtained by washing lower layer slurry (containing a molecular sieve and partial incompletely cut mother liquor) and performing solid-liquid separation after crystallization of NaY molecular sieve materials is completed and the mother liquor is cut off; the suspended substance refers to fine grains of the NaY molecular sieve remained in the mother solution of the NaY molecular sieve and/or the water washing filtrate of the NaY molecular sieve.
In the present invention, for convenience of explanation, the definitions are given
The mass of the NaY molecular sieve is characterized by a value, wherein,
in the X-ray diffraction spectrum with the value of 5-35 degrees, the corresponding peak intensity at 12.46 degrees of the characteristic peak of X-ray diffraction/the corresponding peak intensity at 23.48 degrees of the characteristic peak of X-ray diffraction (in the X-ray diffraction spectrum with the value of 5-35 degrees, the corresponding diffraction peak at 12.46 degrees is the characteristic peak of NaP mixed crystal, and the corresponding diffraction peak at 23.48 degrees is the characteristic peak of NaY type molecular sieve).
The smaller the value, the less the NaP mixed crystal content in the NaY molecular sieve, the better the quality.
The invention provides a method for treating NaY molecular sieve waste liquid, which comprises the following steps:
1) carrying out solid-liquid separation on the NaY molecular sieve waste liquid to ensure that the content of suspended matters in a liquid phase obtained by the solid-liquid separation is below 300 mg/L;
2) contacting the liquid phase with aluminum salt to prepare silica-alumina gel,
wherein the NaY molecular sieve waste liquid contains NaY molecular sieve mother liquid and/or washing filtrate.
According to the present invention, in step 1), the solid-liquid separation may be performed by various methods commonly used in the art for separating solids and liquids, without particular limitation. For example, filtration, centrifugation, membrane separation, etc. may be employed, as long as the objective of reducing the suspended matter content in the liquid phase of the present invention to 300mg/L or less can be achieved. Preferably, the solid-liquid separation is performed by adopting a membrane separation mode.
According to the invention, solid-liquid separation is carried out on the NaY molecular sieve waste liquid, so that the content of suspended matters in the obtained liquid phase is reduced to below 300mg/L, and then the liquid phase is recycled to prepare the silica-alumina gel.
The inventors of the present invention passed throughAfter analyzing a plurality of influence factors, the practice and research of the amount find that the NaY molecular sieve is obtained by reducing the suspension content in the liquid phase to be less than 300mg/L and then utilizing the liquid phase to prepare silica-alumina gel and further recycling the silica-alumina gel to the synthesis of the NaY molecular sieve
The value is reduced, the quality of the NaY molecular sieve is improved, and the utilization rate of silicon can be obviously improved. The reason for this is probably that when the content of suspended matter in the NaY molecular sieve waste liquid is higher than the above range, fine grains of the NaY molecular sieve become NaP mixed crystals in the crystallization process when the recovered NaY molecular sieve waste liquid is further used for synthesizing the NaY molecular sieve, thereby affecting the quality of the obtained NaY molecular sieve and also limiting the utilization rate of silicon.
Therefore, in the invention, the content of suspended matters in the NaY molecular sieve waste liquid is reduced to be less than 300mg/L, so that the generation amount of NaP mixed crystals can be effectively controlled, the quality of the NaY molecular sieve is further controlled, and the utilization rate of silicon is improved.
According to the invention, SiO is preferably contained in the NaY molecular sieve waste liquid2The content of (A) is 16-50g/L, Na2The content of O is 15-23g/L, and the content of suspended matters is 800-6000 mg/L; more preferably, SiO is contained in the NaY molecular sieve waste liquid2Has a content of 28-45g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1000-4500 mg/L; further preferably, SiO is contained in the NaY molecular sieve waste liquid2The content of (A) is 29-32g/L, Na2The content of O is 18-20g/L, and the content of suspended matters is 2000-4000 mg/L.
In a preferred embodiment of the present invention, in the NaY molecular sieve mother liquor, SiO2Has a content of 36-50g/L, Na2The content of O is 18-23g/L, and the content of suspended matters is 800-2500 mg/L; preferably, in the NaY molecular sieve mother liquor, SiO2Has a content of 38-45g/L, Na2The content of O is 19-22g/L, and the content of suspended matters is 1000-2000 mg/L.
In a preferred embodiment of the present invention, SiO is contained in the NaY molecular sieve washing filtrate2Has a content of 16-35g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1500-6000 mg/L; preferably, SiO in the NaY molecular sieve washing filtrate2The content of (A) is 25-32g/L, Na2The content of O is 18-20g/L, and the content of suspended matters is 2500-4500 mg/L.
In a particularly preferred embodiment of the invention, the NaY molecular sieve waste liquid is a mixed liquid of NaY molecular sieve mother liquid and NaY molecular sieve washing filtrate.
According to the invention, after the solid-liquid separation is carried out on the NaY molecular sieve waste liquid, the obtained solid phase contains the NaY molecular sieve.
According to the invention, after solid-liquid separation is carried out on the NaY molecular sieve waste liquid, the obtained liquid phase is contacted with aluminum salt to prepare the silica-alumina gel. The aluminum salt may be various aluminum salts commonly used in the art for preparing silica alumina gel, without particular limitation. For example, the aluminum salt may be aluminum sulfate and/or aluminum chloride; preferably, the aluminium salt is aluminium sulphate.
In the present invention, the aluminum salt may be used in the form of a solid or a solution, preferably, the aluminum salt is used in the form of a solution, the amount of the aluminum salt solution may be determined according to the silicon content of the liquid phase, the molar ratio of the liquid phase in terms of silica to the aluminum salt in terms of aluminum element is 3 to 8:1, and preferably, the molar ratio of the liquid phase in terms of silica to the aluminum salt in terms of aluminum element is 4 to 5.5: 1. When the dosage of the aluminum salt is less than the range, the phenomenon of silicon leakage can occur in the preparation process of the silica-alumina gel, and partial silicon and aluminum can not be completely settled, so that the silicon and aluminum enter the filtrate in a free state, and the silica-alumina gel is difficult to filter; when the dosage of the aluminum salt is higher than the range, aluminum leakage can occur in the preparation process of the silica-alumina gel, part of aluminum enters the filtrate in a free state, incomplete separation can be caused during solid-liquid separation of the silica-alumina gel, more water is carried, the content of impurities is high, and the synthesis of the NaY molecular sieve is further influenced.
According to the present invention, the contacting may be performed in various ways as long as the purpose of the silica alumina gel preparation of the present invention can be achieved, and is not particularly limited. For example, the liquid phase may be added to the aluminum salt or aluminum salt solution, the aluminum salt or aluminum salt solution may be added to the liquid phase, or the aluminum salt or aluminum salt solution and the liquid phase may be simultaneously added to a silica gel reaction apparatus. In the present invention, preferably, the liquid phase and the aluminum salt or aluminum salt solution are simultaneously fed into a silica-alumina gel reaction apparatus. The content of the aluminum salt in the aluminum salt solution may be, for example, 21 to 25.8% by weight.
According to the invention, in order to better contact the liquid phase and the aluminum salt solution to prepare the silica-alumina gel, the gel forming process of the silica-alumina gel is preferably carried out under stirring; more preferably, the gelling temperature is 30-60 ℃, and the gelling residence time is 10-20 min; further preferably, the gelling temperature is 45-55 ℃, and the gelling residence time is 13-18 min. By carrying out the gelling under the conditions, the silicon in the liquid phase and the aluminum in the added aluminum salt can be fully subjected to gelling reaction, the loss of silicon and aluminum is avoided, the speed of the silicon-aluminum gelling reaction can be controlled within a proper range, and the crystal purity of the NaY molecular sieve in the crystallization process can be prevented from being influenced by excessive aging of the silicon-aluminum gel.
According to the invention, in order to remove impurities and improve the quality of the silica-alumina gel, the gel-forming product can be further filtered, washed and dried in different regions to prepare the silica-alumina gel. The method of filtering, washing and drying is not particularly limited, and various methods commonly used in the art for filtering, washing and drying in the preparation process of silica alumina gel may be used, and will not be described herein again.
Reducing the sulfate radical content in the silica-alumina gel to below 5 weight percent through the processes of filtering, washing and drying; preferably, the sulfate content in the silica alumina gel is reduced to less than 3 wt%.
According to the invention, the silica-alumina gel prepared by treating the NaY molecular sieve waste liquid can be further recycled to the preparation of the NaY molecular sieve, and the preparation of the NaY molecular sieve can be carried out by adopting a guide agent method commonly used for preparing molecular sieves in the field.
In the present invention, the preparation of the directing agent can be carried out as follows: sodium silicate and high-alkali sodium metaaluminate react for 1-3h at 25-45 ℃ under the condition of stirring, and the reaction is finishedStopping stirring, standing at constant temperature for aging for 14-24h, adding water after aging, and stirring to obtain guiding agent. Wherein, Na2O、Al2O3、SiO2And H2The molar ratio of O is 15-16:1:14-16: 320-380.
According to the invention, sodium silicate and silica-alumina gel prepared by the method are used as silicon sources, aluminum sulfate and low-alkali sodium metaaluminate are used as aluminum sources, and a guiding agent method is adopted to prepare the NaY molecular sieve. Uniformly mixing a silicon source, an aluminum source, the guiding agent prepared by the method and water in a certain ratio at the temperature of 20-45 ℃ under the stirring condition, adjusting the pH of a reaction system to 11.7-12.4, and then continuously stirring for 1-3 h. Then crystallizing for 30-50h at 90-110 ℃ in a crystallization tank. Wherein, Na2O、Al2O3、SiO2And H2The molar ratio of O is 2.5-2.8:1:8.4-9:190-220, and the silicon in the silica-alumina gel prepared by the method of the invention accounts for 0.1-36 wt%, preferably 15-36 wt%, and more preferably 22-36 wt% of the total silicon fed. Thus preparing the NaY molecular sieve.
The present invention will be described in detail below by way of examples. In the following examples and comparative examples, the NaY molecular sieve waste liquid used was a mixed liquid of NaY molecular sieve mother liquid and NaY molecular sieve washing filtrate; the membrane used for membrane separation is an inorganic ceramic membrane (Hefeijie membrane engineering Co., Ltd., membrane pore diameter 50 nm); other raw materials used had the following properties: high alkali sodium metaaluminate: na (Na)2The content of O was 275g/L, Al2O3The content of (A) is 40 g/L; low alkali sodium metaaluminate: na (Na)2O content of 280g/L, Al2O3The content of (A) is 180 g/L; sodium silicate: na (Na)2O content of 84.0g/L, SiO2The content of (A) is 260 g/L; aluminum sulfate: al (Al)2O3The content of (B) is 90 g/L.
Example 1
1) Solid-liquid separation: SiO in NaY molecular sieve waste liquid2The content of Na is 31.2g/L2O content of 18.3g/L and suspended matter content of 3360mg/L, membrane separation at 0.34MPa and 52 deg.C to obtain SiO in liquid phase2The concentration is 30.1g/L, Na2Concentration of OThe degree is 18.1g/L, and the concentration of suspended matters is 30 mg/L;
2) preparing silica-alumina gel: adding the liquid phase obtained in the step 1) and an aluminum sulfate solution with the weight percent of 22.5 into a silica-alumina gel reaction kettle, wherein the molar ratio of the liquid phase calculated by silicon dioxide to the aluminum sulfate calculated by aluminum element is 5.5:1, then stirring for 15min at 50 ℃, filtering, washing and drying a reaction product to obtain the silica-alumina gel, wherein the sulfate radical content of the obtained product is 1.73 wt%, and the obtained silica-alumina gel comprises the following components in percentage by weight: SiO 2269.06 wt.% Al2O316.72 wt.% Na2O12.49 wt%;
3) preparation of a guiding agent: 93.5mL of water glass and 68.9mL of high-alkali sodium metaaluminate react for 1h at 30 ℃ under stirring, the mixture is kept stand and aged for 18h at constant temperature after the reaction is finished, 27.1mL of water is added after the aging is finished, and the guiding agent is prepared after the uniform stirring;
4) synthesis of NaY molecular sieve: 336mL of sodium silicate, 356.6mL of silica-alumina gel (220g/L) prepared in the step 2), 80.3mL of aluminum sulfate, 49.1mL of low-alkali sodium metaaluminate and 82.1mL of guiding agent prepared in the step 3) are added, 182.3mL of water is added, the mixture stays for 1h under the conditions of 30 ℃, pH value of 12.2 and stirring, then the mixture is transferred to a crystallization tank, and is crystallized for 40h at 105 ℃ to obtain the NaY molecular sieve, wherein the silicon in the recycled silica-alumina gel accounts for 36 wt% of the total silicon of the NaY molecular sieve synthesis feed.
The results are shown in table 1, and the X-ray diffraction pattern of the NaY molecular sieve thus prepared is shown in fig. 1.
Example 2
The procedure is as described in example 1, except that:
in the step 1), SiO is contained in the NaY molecular sieve waste liquid2The concentration is 30.1g/L, Na2The concentration of O is 19.2g/L, the concentration of suspended matters is 3210mg/L, and SiO is contained in the liquid phase obtained after membrane separation2The concentration is 29.8g/L, Na2The concentration of O is 18.5g/L, and the concentration of suspended matters is 88 mg/L;
in the step 2), the molar ratio of the liquid phase calculated by silicon dioxide to the aluminum sulfate calculated by aluminum element is 5:1, the content of sulfate radicals in the obtained product is 1.49 wt%, and the obtained silica-alumina gel comprises the following components: SiO 2269.8 wt.% of Al2O316.73 wt%, Na2O11.98 wt%;
in the step 4), 359.7mL of sodium silicate, 315.7mL of silica-alumina gel prepared in the step 2), 90.7mL of aluminum sulfate, 52.8mL of low-alkali sodium metaaluminate, 82.1mL of directing agent and 184.5mL of water are added, wherein the silicon in the recycled silica-alumina gel accounts for 32 wt% of the total silicon of the NaY molecular sieve synthesis feed.
The results are shown in table 1, and the X-ray diffraction pattern of the NaY molecular sieve thus prepared is shown in fig. 2.
Example 3
The procedure is as described in example 1, except that:
in the step 1), SiO is contained in the NaY molecular sieve waste liquid2The concentration of Na is 29g/L2The concentration of O is 18.6g/L, the concentration of suspended matters is 3530mg/L, and SiO is contained in a liquid phase obtained after membrane separation2The concentration is 28.5g/L, Na2The concentration of O is 18.2g/L, and the concentration of suspended matters is 150 mg/L;
in the step 2), the molar ratio of the liquid phase calculated by silicon dioxide to the aluminum sulfate calculated by aluminum element is 4.5:1, the content of sulfate radicals in the obtained product is 1.64 wt%, and the obtained silica-alumina gel comprises the following components: SiO 2269.58 wt.% Al2O316.67 wt.% Na2O12.11 wt%;
in the step 4), 395mL of sodium silicate, 257.9mL of silica-alumina gel prepared in the step 2), 107.1mL of aluminum sulfate, 56.8mL of low-alkali sodium metaaluminate, 82.1mL of directing agent and 189.9mL of water are added, wherein silicon in the recycled silica-alumina gel accounts for 26 wt% of the total silicon of the NaY molecular sieve synthesis feed.
The results are shown in table 1, and the X-ray diffraction pattern of the NaY molecular sieve thus prepared is shown in fig. 3.
Example 4
The procedure is as described in example 1, except that:
in the step 1), SiO is contained in the NaY molecular sieve waste liquid2The concentration is 29.2g/L, Na2The concentration of O is 18.3g/L, the concentration of suspended matters is 2860mg/L, and SiO is contained in a liquid phase obtained after membrane separation2The concentration is 28.5g/L, Na2O concentration of17.8g/L, the concentration of suspended matters is 260 mg/L;
in the step 2), the molar ratio of the liquid phase calculated by silicon dioxide to the aluminum sulfate calculated by aluminum element is 4:1, the content of sulfate radicals in the obtained product is 1.76 wt%, and the content of each component in the obtained silica-alumina gel is as follows: SiO 2270.47 wt.% Al2O316.22 wt%, Na2O11.55 wt%;
in the step 4), 418.5mL of sodium silicate, 216.1mL of silica-alumina gel prepared in the step 2), 118.4mL of aluminum sulfate, 61.1mL of low-alkali sodium metaaluminate, 82.1mL of directing agent and 186.6mL of water are added, wherein silicon in the recycled silica-alumina gel accounts for 22 wt% of the total silicon of the NaY molecular sieve synthesis feed.
The results are shown in table 1, and the X-ray diffraction pattern of the NaY molecular sieve thus prepared is shown in fig. 4.
Comparative example 1
The procedure is as described in example 1, except that:
in the step 1), SiO is contained in the NaY molecular sieve waste liquid2The concentration is 38.2g/L, Na2The concentration of O is 19.1g/L, the concentration of suspended matters is 2360mg/L, after continuous sedimentation is carried out in a sedimentation tank for 7 hours, supernatant liquor is collected, wherein, SiO2The concentration is 28.5g/L, Na2The concentration of O is 17.8g/L, and the concentration of suspended matters is 452 mg/L;
in the step 2), the molar ratio of the liquid phase calculated by silicon dioxide to the aluminum sulfate calculated by aluminum element is 4:1, the content of sulfate radicals in the obtained product is 2.14 wt%, and the obtained silica-alumina gel comprises the following components: SiO 2269.12 wt.% Al2O316.61 wt.% Na2O12.13 wt%;
in the step 4), 418.5mL of sodium silicate, 220.1mL of silica-alumina gel prepared in the step 2), 117.4mL of aluminum sulfate, 59.7mL of low-alkali sodium metaaluminate, 82.1mL of directing agent and 185.1mL of water are added, wherein silicon in the recycled silica-alumina gel accounts for 22 wt% of the total silicon of the NaY molecular sieve synthesis feed.
The results are shown in table 1, and the X-ray diffraction pattern of the NaY molecular sieve thus prepared is shown in fig. 5.
TABLE 1
As can be seen by combining FIGS. 1-5 and Table 1, the silicon utilization of example 1 can be as high as 99.8%, much higher than 85.2% in comparative example 1, and the relative crystallinity of the resulting NaY molecular sieve
The values are also clearly superior to the comparative examples. Therefore, when the treatment method of the NaY molecular sieve waste liquid is adopted, the content of suspended matters in the NaY molecular sieve waste liquid is reduced to 300mg/L, and the silica-alumina gel prepared from the waste liquid is further recycled to the preparation of the NaY molecular sieve, the quality of the NaY molecular sieve can be improved, and the utilization rate of silicon can be obviously improved.
On the other hand, when the utilization rate of silicon is the same (refer to example 4 and comparative example 1), the relative crystallinity of the NaY molecular sieve prepared by the silica-alumina gel prepared by the method of the invention is obviously higher than that of comparative example 1, and the obtained NaY molecular sieve
The values are much lower than in the comparative example. As can be seen from a comparison of FIGS. 4 and 5, the peak at the NaP mixed crystal (circled part in the figure) in FIG. 4 is significantly reduced. Therefore, even under the condition that the utilization rate of silicon is the same, the quality of the molecular sieve can be obviously improved, the crystallinity of the molecular sieve is improved, and the content of NaP mixed crystals is reduced.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (10)
1. A treatment method of NaY molecular sieve waste liquid is characterized by comprising the following steps:
1) carrying out solid-liquid separation on the NaY molecular sieve waste liquid to ensure that the content of suspended matters in a liquid phase obtained by the solid-liquid separation is below 300 mg/L;
2) contacting the liquid phase with aluminum salt to prepare silica-alumina gel;
wherein the NaY molecular sieve waste liquid contains NaY molecular sieve mother liquid and/or washing filtrate.
2. The process according to claim 1, wherein in step 1), the solid phase obtained by the solid-liquid separation contains a NaY molecular sieve.
3. The treatment method of claim 1, wherein SiO is contained in the NaY molecular sieve waste liquid2The content of (A) is 16-50g/L, Na2The content of O is 15-23g/L, and the content of suspended matters is 800-6000 mg/L;
preferably, SiO in the NaY molecular sieve waste liquid2Has a content of 28-45g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1000-4500 mg/L.
4. The process of claim 1, wherein the NaY molecular sieve mother liquor is SiO2Has a content of 36-50g/L, Na2The content of O is 18-23g/L, and the content of suspended matters is 800-2500 mg/L;
preferably, in the NaY molecular sieve mother liquor, SiO2Has a content of 38-45g/L, Na2The content of O is 19-22g/L, and the content of suspended matters is 1000-2000 mg/L;
SiO in the NaY molecular sieve washing filtrate2Has a content of 16-35g/L, Na2The content of O is 15-22g/L, and the content of suspended matters is 1500-6000 mg/L;
preferably, SiO in the NaY molecular sieve washing filtrate2The content of (A) is 25-32g/L, Na2The content of O is 18-20g/L, and the content of suspended matters is 2500-4500 mg/L.
5. The treatment process according to any one of claims 1 to 4, wherein in step 2), the aluminum salt is aluminum sulfate and/or aluminum chloride;
preferably, the aluminium salt is aluminium sulphate.
6. The treatment process according to any one of claims 1 to 4, wherein in step 2), the molar ratio of the liquid phase, calculated as silica, to the aluminium salt, calculated as elemental aluminium, is from 3 to 8: 1;
preferably, the conditions for preparing the silica alumina gel include: the gelatinizing temperature is 30-60 ℃, and the gelatinizing retention time is 10-20 min;
more preferably, the conditions for preparing the silica alumina gel include: the gelling temperature is 45-55 ℃, and the gelling retention time is 13-18 min.
7. The processing method according to any one of claims 1 to 6, wherein the method further comprises: the silica-alumina gel prepared in the step 2) is used for preparing the NaY molecular sieve.
8. The process of claim 7, wherein when the silica alumina gel prepared in step 2) is used for preparing the NaY molecular sieve, the silica in the silica alumina gel prepared in step 2) accounts for 0.1 to 36 wt%, preferably 15 to 36 wt%, and more preferably 22 to 36 wt% of the total silica in the NaY molecular sieve.
9. Use of the method of any one of claims 1 to 8 for treating NaY molecular sieve waste liquor in treating NaY molecular sieve mother liquor and/or water wash filtrate.
10. A NaY molecular sieve prepared by the method for treating the NaY molecular sieve waste liquid of claim 7 or 8.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4164551A (en) * | 1977-12-19 | 1979-08-14 | W. R. Grace & Co. | Preparation of zeolite |
| CN1634764A (en) * | 2003-12-25 | 2005-07-06 | 中国石油化工股份有限公司 | Process for preparing NaY molecular sieve by using synthetic mother liquor |
| CN102050468A (en) * | 2009-10-27 | 2011-05-11 | 中国石油化工股份有限公司 | Method for preparing NaY molecular sieve by using crystallized mother liquor of molecular sieve |
| CN108264075A (en) * | 2016-12-30 | 2018-07-10 | 中国石油化工股份有限公司 | A kind of NaY crystallization mother liquors for being used to prepare porous material and/or the reclaiming system of filtrate |
| CN108927123A (en) * | 2017-05-26 | 2018-12-04 | 中国石油化工股份有限公司 | A kind of porous catalyst material and preparation method thereof |
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2020
- 2020-07-02 CN CN202010634477.0A patent/CN113880105A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4164551A (en) * | 1977-12-19 | 1979-08-14 | W. R. Grace & Co. | Preparation of zeolite |
| CN1634764A (en) * | 2003-12-25 | 2005-07-06 | 中国石油化工股份有限公司 | Process for preparing NaY molecular sieve by using synthetic mother liquor |
| CN102050468A (en) * | 2009-10-27 | 2011-05-11 | 中国石油化工股份有限公司 | Method for preparing NaY molecular sieve by using crystallized mother liquor of molecular sieve |
| CN108264075A (en) * | 2016-12-30 | 2018-07-10 | 中国石油化工股份有限公司 | A kind of NaY crystallization mother liquors for being used to prepare porous material and/or the reclaiming system of filtrate |
| CN108927123A (en) * | 2017-05-26 | 2018-12-04 | 中国石油化工股份有限公司 | A kind of porous catalyst material and preparation method thereof |
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