阅读说明：本技术 一种低硅x分子筛合成母液的循环利用方法 (Recycling method of low-silicon X molecular sieve synthesis mother liquor ) 是由 白长敏 徐云鹏 刘中民 刘广业 袁丹华 于 2018-06-21 设计创作，主要内容包括：本申请公开了一种低硅X分子筛合成母液的全循环利用方法,所述方法包括,在制备分子筛过程中,将产物分离出母液后,向母液中补充添加铝源、钾源和钠源并循环利用。采用本发明的方法合成低硅分子筛所产生的母液得到了循环利用,可充分节省原料成本,具有经济意义；在母液循环利用过程中,没有合成废液排放,对环境友好,又节省了废液处理的费用,每增加一遍母液利用,都具有经济和环保的双重意义。(The application discloses a full recycling method of a low-silicon X molecular sieve synthesis mother liquor, which comprises the steps of separating a product from the mother liquor in the molecular sieve preparation process, supplementing an aluminum source, a potassium source and a sodium source into the mother liquor, and recycling. The mother liquor generated by synthesizing the low-silicon molecular sieve by adopting the method is recycled, so that the raw material cost can be fully saved, and the method has economic significance; in the process of recycling the mother liquor, no synthetic waste liquor is discharged, the method is environment-friendly, the cost for treating the waste liquor is saved, and the method has economic and environment-friendly significance when the mother liquor is used once.)

1. A recycling method of low-silicon X molecular sieve synthesis mother liquor is characterized by comprising the following steps:

1) mixing an aluminum source, a sodium source, a potassium source and water to obtain a solution A0; mixing a silicon source and water to obtain a solution B0; adding B0 into A0, aging and crystallizing the obtained mixture C0, and separating to obtain low-silicon X molecular sieve and mother liquid (the serial number "0" indicates that all fresh raw materials are adopted in the formula, and no mother liquid component is added);

2) quantitatively detecting components in the mother liquor by adopting an ion chromatography external standard method;

3) according to the detection result of the step 2), additionally adding An aluminum source, a sodium source and a potassium source into the mother liquor subjected to quantitative detection to obtain a mixture An; mixing a silicon source and water to obtain a solution Bn, adding the Bn into An, aging and crystallizing the obtained mixture Cn, and separating to obtain a low-silicon X molecular sieve and a mother solution;

4) and (3) repeatedly repeating the steps 2) to 3), thereby realizing the recycling of the mother liquor in the synthesis of the low-silicon X molecular sieve.

2. The method for recycling a mother liquor for synthesizing a low-silicon X molecular sieve as claimed in claim 1, wherein in the mixture C0 of the step 1), the molar ratio of the sodium source, the potassium source, the aluminum source, the silicon source and the water is as follows:

Na₂O(2.0～6.0)：K₂O(1.0～4.0):Al₂O₃(1.0～2.5):SiO₂(0.5～2.0):H₂O(80～150)；

wherein the mole number of the sodium source is Na₂The mole number of O; the mole number of the potassium source is K₂The mole number of O; the mole number of the aluminum source is Al₂O₃In terms of moles; the mole number of the silicon source is SiO₂In terms of moles; the mole number of the water is H₂And the mole number of O.

3. The method for recycling a mother liquor for synthesizing a low-silicon X molecular sieve as claimed in claim 1, wherein in the mixture Cn of the step 3), the molar ratio of the sodium source, the potassium source, the aluminum source, the silicon source and the water is as follows:

Na₂O(2.0～6.0)：K₂O(1.0～4.0):Al₂O₃(1.0～2.5):SiO₂(0.5～2.0):H₂O(80～150)；

wherein the mole number of the sodium source is Na₂The mole number of O; the mole number of the potassium source is K₂The mole number of O; the mole number of the aluminum source is Al₂O₃In terms of moles; the mole number of the silicon source is SiO₂In terms of moles; the mole number of the water is H₂And the mole number of O.

4. The recycling method of the low-silicon X molecular sieve synthesis mother liquor according to claim 1, wherein the aging in the step 1) and the step 3) is performed for 6-10 hours at 55-70 ℃.

5. The recycling method of the low-silicon X molecular sieve synthesis mother liquor according to claim 1, wherein the crystallization in the step 1) and the step 3) is performed at 100-110 ℃ for 5-9 h.

6. The method of claim 1, wherein the ion chromatography external standard method comprises detecting the ion concentration of the mother liquor by using methanesulfonic acid as an eluent and based on the response relationship between the ion conductivity peak area and the ion concentration, and converting the mass fraction of each component in the mother liquor by using the ion concentration.

7. The method for recycling a mother liquor for synthesizing a low-silicon X molecular sieve according to claim 6, wherein the leacheate is 26mmol/L methanesulfonic acid.

8. The method for recycling a mother liquor for synthesizing a low-silicon X molecular sieve according to claim 1, wherein the sodium source is at least one selected from sodium sulfate, sodium nitrate and sodium hydroxide;

the potassium source is at least one of potassium sulfate, potassium nitrate and potassium hydroxide;

the silicon source is at least one of silica sol, sodium silicate and potassium silicate;

the aluminum source is at least one selected from pseudo-boehmite, alumina, sodium aluminate, potassium aluminum sulfate and potassium aluminate.

9. The method of claim 1, wherein the CO at 25 ℃ and 250mmHg is recycled₂Under air pressure, the low-silicon X molecular sieve is used for CO₂Has an adsorption capacity of more than 100cm³/g。

10. The method of claim 1, wherein the CO at 25 ℃ and 250mmHg is recycled₂Under air pressure, the low-silicon X molecular sieve is used for CO₂Has an adsorption capacity of 100cm³/g～120cm³/g。

Technical Field

The application relates to a recycling method of a low-silicon X molecular sieve synthesis mother solution, belonging to the field of inorganic chemistry and material chemistry.

Background

The low-silicon X molecular sieve has wide application in the field of pressure swing adsorption oxygen generation, is also widely applied to industries such as petrochemical industry, medicine, agriculture, building, automobile and the like as an adsorbent, and is also widely used as a washing assistant for water softening in the washing industry. The laboratory synthesis method of the low-silicon molecular sieve generally comprises a hydrothermal synthesis method andthe solid-phase synthesis method and the hydrothermal synthesis have the characteristic of uniform mass and heat transfer, the high-purity-phase low-silicon molecular sieve is easy to obtain, and the adsorption capacity and the ion exchange capacity are higher, so that the hydrothermal synthesis has higher application value and can be widely applied to large-scale production. However, the yield of the low-silicon molecular sieve obtained by the hydrothermal synthesis method is low, the product yield is 10-13% calculated by the total feeding amount, a large amount of waste liquid, namely mother liquid, is generated in the production process, and the mother liquid contains unused Na₂O、K₂O、Al₂O₃、SiO₂If the mother liquor is directly discharged, the loss of raw materials and the environmental pollution are inevitably caused, so how to effectively utilize the mother liquor is a key point and a difficult point in the molecular sieve synthesis industry.

CN1406868A discloses a hydrothermal synthesis method of a low-silicon molecular sieve, which utilizes waste residue or mother liquor of a catalyst plant as part of raw materials for synthesis to synthesize the low-silicon molecular sieve, but the synthesis process also has the problem of generating a large amount of waste liquid.

CN104174356A discloses a method for preparing a low-silicon molecular sieve, but a guiding agent needs to be prepared in the synthesis process, in the mentioned mother liquor utilization scheme, the mother liquor needs to be collected and stored, and the mother liquor is concentrated and processed for reuse, in the production process, fresh deionized water needs to be added while water in the mother liquor is evaporated, and the problems of more processes, more equipment, high energy consumption and long production process exist.

The method focuses on self recycling, and the mother liquor obtained after the low-silicon molecular sieve is synthesized by using fresh raw materials is completely and directly used in the next synthesis without any treatment, so that the discharged or stored mother liquor is not generated in the recycling process, and fresh deionized water is not required to be added, and a guiding agent is not required to be prepared, so that the method has double meanings of economy and environmental protection.

Disclosure of Invention

According to one aspect of the application, a method for recycling a low-silicon X molecular sieve synthesis mother liquor is provided, which is characterized by comprising the following steps:

1) mixing an aluminum source, a sodium source, a potassium source and water to obtain a solution A0; mixing a silicon source and water to obtain a solution B0; adding B0 into A0, aging and crystallizing the obtained mixture C0, and separating to obtain the low-silicon X molecular sieve and a mother solution (the serial number "0" indicates that all fresh raw materials are adopted in the formula, and no mother solution component is added);

2) quantitatively detecting components in the mother liquor by adopting an ion chromatography external standard method;

3) according to the detection result of the step 2), additionally adding An aluminum source, a sodium source and a potassium source into the mother liquor subjected to quantitative detection to obtain a mixture An; mixing a silicon source and water to obtain a solution Bn, adding the Bn into An, aging and crystallizing the obtained mixture Cn, and separating to obtain a low-silicon X molecular sieve and a mother solution;

4) and (3) repeatedly repeating the steps 2) to 3), thereby realizing the recycling of the mother liquor in the synthesis of the low-silicon X molecular sieve.

In the method, the raw materials necessary for producing the molecular sieve product are added into the mother liquor, so that the mother liquor is reused, and all the mother liquor is recycled, so that the production cost is greatly reduced, and the problem of waste liquor discharge is solved.

Preferably, in the mixture C0 in step 1), the molar ratio of the sodium source, the potassium source, the aluminum source, the silicon source and the water is:

Na₂O(2.0～6.0)：K₂O(1.0～4.0):Al₂O₃(1.0～2.5):SiO₂(0.5～2.0):H₂O(80～150)；

wherein the mole number of the sodium source is Na₂The mole number of O; the mole number of the potassium source is K₂The mole number of O; the mole number of the aluminum source is Al₂O₃In terms of moles; the mole number of the silicon source is SiO₂In terms of moles; the mole number of the water is H₂And the mole number of O.

Preferably, in the mixture Cn of the step 3), the molar ratio of the sodium source, the potassium source, the aluminum source, the silicon source and the water is as follows:

Na₂O(2.0～6.0)：K₂O(1.0～4.0):Al₂O₃(1.0～2.5):SiO₂(0.5～2.0):H₂O(80～150)；

wherein the mole number of the sodium source is Na₂The mole number of O; the mole number of the potassium source is K₂The mole number of O; the mole number of the aluminum source is Al₂O₃In terms of moles; the mole number of the silicon source is SiO₂In terms of moles; the mole number of the water is H₂And the mole number of O.

Preferably, the aging in the step 1) and the step 3) is performed for 6-10 hours at the temperature of 55-70 ℃.

Preferably, the crystallization in the step 1) and the step 3) is performed for 5-9 hours at the temperature of 100-110 ℃.

Preferably, the ion chromatography external standard method uses methanesulfonic acid as an eluent, detects the ion concentration in the mother liquor based on the response relation between the ion conductivity peak area and the ion concentration, and converts the mass fraction of each component in the mother liquor by using the ion concentration.

Preferably, the leacheate is 26mmol/L methanesulfonic acid.

Preferably, the sodium source is selected from at least one of sodium sulfate, sodium nitrate, and sodium hydroxide;

the potassium source is at least one of potassium sulfate, potassium nitrate and potassium hydroxide;

the silicon source is at least one of silica sol, sodium silicate and potassium silicate;

the aluminum source is at least one selected from pseudo-boehmite, alumina, sodium aluminate, potassium aluminum sulfate and potassium aluminate.

Preferably, 250mmHg of CO at 25 deg.C₂Under air pressure, the low-silicon X molecular sieve is used for CO₂Has an adsorption capacity of more than 100cm³/g。

Preferably, 250mmHg of CO at 25 deg.C₂Under air pressure, the low-silicon X molecular sieve is used for CO₂Has an adsorption capacity of 100cm³/g～120cm³/g。

The beneficial effects that this application can produce include:

1) the mother liquor generated by synthesizing the low-silicon molecular sieve is recycled, so that the raw material cost can be fully saved, and the method has economic significance;

2) in the process of recycling the mother liquor, new deionized water is not needed to be added, no synthetic waste liquor is stored and discharged, the method is environment-friendly, the cost of the deionized water and equipment is saved, the cost of waste liquor treatment is saved, and the method has economic and environment-friendly significance when the mother liquor is used once.

3) The method for synthesizing the low-silicon molecular sieve by adopting the hydro-thermal method has the characteristics of uniform heat and mass transfer, easy obtainment of high-purity phase products and good adsorption performance of the products, and is suitable for large-scale industrial production.

Drawings

FIG. 1 is a scanning electron micrograph of a low silicon X molecular sieve product M0.

FIG. 2 is a scanning electron micrograph of low silicon X molecular sieve product M1.

FIG. 3 is a scanning electron micrograph of low silicon X molecular sieve product M2.

FIG. 4 is a scanning electron micrograph of low silicon X molecular sieve product M3.

FIG. 5 is a scanning electron micrograph of low silicon X molecular sieve product M4.

FIG. 6 is a scanning electron micrograph of low silicon X molecular sieve product M5.

FIG. 7 is a comparison of XRD patterns of low-silicon X molecular sieves synthesized by mother liquor circulation.

FIG. 8 is a comparison of adsorption performance of low-silicon X molecular sieves synthesized by mother liquor circulation.

M0 is a low-silicon molecular sieve product produced by first-pass synthesis under the condition that no mother liquor exists in the formula; m1 is a low-silicon molecular sieve product produced by reformulating all mother liquor obtained by synthesizing M0, namely, the first mother liquor, M2 is a low-silicon molecular sieve product produced by reformulating all mother liquor obtained by synthesizing M1, namely, the second mother liquor, and the like.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials in the examples of the present application were purchased commercially, and the equipment used was the manufacturer's recommended parameters.