Method for preparing SOD (superoxide dismutase) molecular sieve by resource utilization of red mud and fly ash

Abstract

The invention discloses a method for preparing an SOD (superoxide dismutase) molecular sieve by resource utilization of red mud and fly ash, which comprises the following steps: step 1, mixing the red mud and the fly ash according to a certain proportion, and carrying out acid leaching treatment; 2, alkali melting treatment is conducted on the mixture obtained after acid leaching treatment; 3, carrying out a hydrothermal synthesis reaction on a product subjected to the alkali melting treatment; and 4, carrying out solid-liquid separation, washing, drying and other post-treatments on the product after the hydrothermal synthesis reaction to obtain the SOD molecular sieve product. Silicon and aluminum components in the fly ash are utilized, a large number of reagents do not need to be added, the production cost is reduced, and therefore the new environmental pollution problem is avoided, the resource utilization rate of the red mud and the fly ash is increased, pollution to the environment is reduced, and the prepared SOD molecular sieve has the advantages of being high in silicon-aluminum ratio, good in product quality, high in yield and suitable for industrial production. Good application prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sieve preparation, and particularly relates to a method for resource utilization of red mud and fly ash to prepare SOD molecular sieve and a preparation method thereof. Background Art

[0002] In recent years, with the continuous advancement of the industrialization process, the generation of solid waste such as red mud and fly ash has been increasing continuously. How to realize their resource utilization has become the focus of the industry. Red mud is a strongly alkaline solid waste generated during the production of alumina from bauxite, while fly ash is the main solid waste discharged from coal-fired power plants. Since red mud and fly ash contain rich silicon and aluminum components, their application in the preparation of molecular sieves has good prospects.

[0003] However, in the prior art, the resource utilization rate of red mud and fly ash is relatively low, and there are certain environmental pollution problems. The soluble sodium in red mud is the main source of its alkalinity. Under the action of dissolution reaction and evaporation, the soluble sodium is easy to migrate to the surface layer of red mud, resulting in the phenomenon of "efflorescence" on the surface of red mud, which has an adverse impact on the environment. At the same time, the silicon-aluminum ratio of fly ash is relatively low, and a large amount of reagents need to be added externally during the preparation of molecular sieves, which not only increases the production cost but also generates new environmental pollution. Summary of the Invention

[0004] Aiming at the defects of the prior art, the purpose of the present invention is to provide a method for resource utilization of red mud and fly ash to prepare SOD molecular sieve, so as to solve the problems raised in the above background art.

[0005] The present invention solves the technical problems by adopting the following technical solutions:

[0006] The present invention provides a method for resource utilization of red mud and fly ash to prepare SOD molecular sieve, comprising the following steps:

[0007] Step 1: Mix red mud and fly ash in a certain proportion and carry out acid leaching treatment;

[0008] Step 2: Carry out alkali melting treatment on the mixture after acid leaching treatment;

[0009] Step 3: Carry out hydrothermal synthesis reaction on the product after alkali melting treatment;

[0010] Step 4: Carry out post-treatment such as solid-liquid separation, washing, and drying on the product after hydrothermal synthesis reaction to obtain SOD molecular sieve product.

[0011] Preferably, the step 1 includes the following steps:

[0012] Step S101: Mix red mud and fly ash according to a silicon-aluminum ratio of 1.5 - 2.5, with red mud accounting for 60 - 80% by weight percentage and fly ash accounting for 20 - 40% by weight percentage;

[0013] Step S102: Acid-leach the mixed materials after batching with a 3 - 5% by weight hydrochloric acid or sulfuric acid solution to reduce the content of soluble sodium in the red mud;

[0014] Step S103: Perform pre-treatments such as water washing and filtration on the mixed materials after acid leaching to remove the residual acid solution.

[0015] Preferably, in step S102, the acid leaching temperature is 70 - 80 °C and the acid leaching time is 1.5 - 2.5 hours.

[0016] Preferably, step two includes:

[0017] Step S201: Mix the pre-treated mixed materials with a 48% by weight sodium hydroxide solution according to an alkali-ash ratio of 1.1 - 1.3;

[0018] Step S202: Perform a melting reaction on the mixed materials to cause a chemical reaction between the silicon-aluminum components in the red mud and fly ash to form a molecular sieve precursor.

[0019] Preferably, in step S202, the melting reaction of the mixed materials is carried out at a temperature of 600 - 700 °C for 3 - 5 hours.

[0020] Preferably, step three includes performing a hydrothermal synthesis reaction on the molecular sieve precursor, which specifically includes the following steps:

[0021] Step S301: Mix the molecular sieve precursor and the structure-directing agent according to a mass ratio of 1:0.2 - 0.4;

[0022] Step S302: Perform a hydrothermal synthesis reaction at a temperature of 150 - 180 °C for 24 - 36 hours to generate SOD molecular sieve crystals.

[0023] Preferably, the structure-directing agent is tetrapropylammonium bromide.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention effectively reduces the content of soluble sodium in red mud through a doping and tempering process, avoids the occurrence of a "floating" phenomenon, and thus reduces adverse effects on the environment; at the same time, the present invention utilizes silicon and aluminum components in fly ash, does not require the addition of a large amount of reagents, reduces production costs, and thus avoids new environmental pollution problems. The present invention improves the resource utilization rate of red mud and fly ash, and reduces pollution to the environment. The SOD molecular sieve prepared by the present invention has a higher silicon-aluminum ratio, excellent product quality, and a higher yield, and has good application prospects. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1.

[0028] A method for preparing SOD molecular sieve by resource utilization of red mud and fly ash in this embodiment comprises the following steps:

[0029] Step 1: Mix red mud and fly ash in a certain proportion and perform acid leaching treatment;

[0030] Step 2, subjecting the mixture after the acid leaching treatment to an alkali melting treatment;

[0031] Step 3, subjecting the product after alkali melting treatment to a hydrothermal synthesis reaction;

[0032] Step 4: The product after the hydrothermal synthesis reaction is subjected to post-treatment such as solid-liquid separation, washing, and drying to obtain a SOD molecular sieve product.

[0033] Step 1 of this embodiment includes the following steps:

[0034] Step S101, red mud and fly ash are mixed according to a silicon-aluminum ratio of 1.5, with red mud accounting for 60% by weight and fly ash accounting for 40% by weight;

[0035] Step S102, acid leaching the mixed mixture with 3 weight percent hydrochloric acid or sulfuric acid solution to reduce the content of soluble sodium in the red mud;

[0036] Step S103, pre-treating the mixture after acid leaching by washing, filtering, etc. to remove residual acid solution.

[0037] In step S102 of this embodiment, the pickling temperature is 70° C. and the pickling time is 1.5 hours.

[0038] Step 2 of this embodiment includes the following steps:

[0039] Step S201, mixing the pretreated mixture with 48 weight percent of sodium hydroxide solution at an alkali-ash ratio of 1.1;

[0040] Step S202: subjecting the mixture to a melting reaction to chemically react the silicon and aluminum components in the red mud and fly ash to form a molecular sieve precursor.

[0041] In step S202 of this embodiment, the mixture is melt-reacted at a temperature of 600° C. for 3 hours.

[0042] Step 3 of this embodiment includes subjecting the molecular sieve precursor to a hydrothermal synthesis reaction, which specifically includes the following steps:

[0043] Step S301, mixing the molecular sieve precursor and the structure directing agent in a mass ratio of 1:0.2;

[0044] Step S302, performing a hydrothermal synthesis reaction at a temperature of 150° C. for 24 hours to generate SOD molecular sieve crystals;

[0045] The structure directing agent in this embodiment is tetrapropylammonium bromide.

[0046] Example 2.

[0047] A method for preparing SOD molecular sieve by resource utilization of red mud and fly ash in this embodiment comprises the following steps:

[0048] Step 1: Mix red mud and fly ash in a certain proportion and perform acid leaching treatment;

[0049] Step 2, subjecting the mixture after the acid leaching treatment to an alkali melting treatment;

[0050] Step 3, subjecting the product after alkali melting treatment to a hydrothermal synthesis reaction;

[0051] Step 4: The product after the hydrothermal synthesis reaction is subjected to post-treatment such as solid-liquid separation, washing, and drying to obtain a SOD molecular sieve product.

[0052] Step 1 of this embodiment includes the following steps:

[0053] Step S101, red mud and fly ash are mixed according to a silicon-aluminum ratio of 2.0, with red mud accounting for 70% by weight and fly ash accounting for 30% by weight;

[0054] Step S102, acid leaching the prepared mixture with 4 weight percent hydrochloric acid or sulfuric acid solution to reduce the content of soluble sodium in the red mud;

[0055] Step S103, pre-treating the mixture after acid leaching by washing, filtering, etc. to remove residual acid solution.

[0056] In step S102 of this embodiment, the pickling temperature is 75° C. and the pickling time is 2.0 hours.

[0057] Step 2 of this embodiment includes the following steps:

[0058] Step S201, mixing the pretreated mixture with 48 weight percent of sodium hydroxide solution at an alkali-ash ratio of 1.2;

[0059] Step S202: subjecting the mixture to a melting reaction to chemically react the silicon and aluminum components in the red mud and fly ash to form a molecular sieve precursor.

[0060] In step S202 of this embodiment, the mixture is subjected to a melting reaction at a temperature of 650° C. for 4 hours.

[0061] Step 3 of this embodiment includes subjecting the molecular sieve precursor to a hydrothermal synthesis reaction, which specifically includes the following steps:

[0062] Step S301, mixing the molecular sieve precursor and the structure directing agent in a mass ratio of 1:0.3;

[0063] Step S302, performing a hydrothermal synthesis reaction at a temperature of 170° C. for 30 hours to generate SOD molecular sieve crystals;

[0064] The structure directing agent in this embodiment is tetrapropylammonium bromide.

[0065] Example 3.

[0066] A method for preparing SOD molecular sieve by resource utilization of red mud and fly ash in this embodiment comprises the following steps:

[0067] Step 1: Mix red mud and fly ash in a certain proportion and perform acid leaching treatment;

[0068] Step 2, subjecting the mixture after the acid leaching treatment to an alkali melting treatment;

[0069] Step 3, subjecting the product after alkali melting treatment to a hydrothermal synthesis reaction;

[0070] Step 4: The product after the hydrothermal synthesis reaction is subjected to post-treatment such as solid-liquid separation, washing, and drying to obtain a SOD molecular sieve product.

[0071] Step 1 of this embodiment includes the following steps:

[0072] Step S101, red mud and fly ash are mixed according to a silicon-aluminum ratio of 2.5, with red mud accounting for 80% by weight and fly ash accounting for 20% by weight;

[0073] Step S102: Acid-leach the mixture after batching with a 5 wt% hydrochloric acid or sulfuric acid solution to reduce the content of soluble sodium in the red mud.

[0074] Step S103: Perform pre-treatments such as water washing and filtration on the mixture after acid leaching to remove the residual acid solution.

[0075] In step S102 of this embodiment, the acid leaching temperature is 80 °C and the acid leaching time is 2.5 hours.

[0076] Step two of this embodiment includes the following steps:

[0077] Step S201: Mix the pre-treated mixture with a 48 wt% sodium hydroxide solution at an alkali-ash ratio of 1.3.

[0078] Step S202: Perform a melting reaction on the mixture to cause a chemical reaction between the silicon and aluminum components in the red mud and fly ash to form a molecular sieve precursor.

[0079] In step S202 of this embodiment, the mixture undergoes a melting reaction at a temperature of 700 °C for 5 hours.

[0080] Step three of this embodiment includes performing a hydrothermal synthesis reaction on the molecular sieve precursor, which specifically includes the following steps:

[0081] Step S301: Mix the molecular sieve precursor with a structure-directing agent at a mass ratio of 1:0.4.

[0082] Step S302: Perform a hydrothermal synthesis reaction at a temperature of 180 °C for 36 hours to generate SOD molecular sieve crystals.

[0083] The structure-directing agent in this embodiment is tetrapropylammonium bromide.

[0084] Comparative Example 1

[0085] A method for preparing molecular sieve by doping and conditioning red mud-biomass ash-fly ash (CN112919490A), which mixes fly ash, red mud and biomass ash according to the required silicon-aluminum ratio of the product, and prepares molecular sieve through steps such as acid leaching, alkali melting and hydrothermal reaction. Although this method realizes the resource treatment of fly ash, red mud and biomass ash, the silicon-aluminum ratio of the molecular sieve is relatively low, and the yield and quality need to be further improved.

[0086] Comparative Example 2

[0087] In step S201, the pre-treated mixture is not mixed with a 48 wt% sodium hydroxide solution at an alkali-ash ratio of 1.1 - 1.3.

[0088] Comparative Example 3

[0089] In step S301, the molecular sieve precursor and the structure directing agent were not mixed at a mass ratio of 1:0.2 - 0.4.

[0090] Calculate the relative crystallinity of Examples 1 - 3 and Comparative Examples 1 - 3. The calculation formula is as follows.

[0091]

[0092] Where X C is the relative crystallinity of the synthesized product, X0 is the crystallinity of the standard sample of this type of molecular sieve, I C is the diffraction intensity of a certain crystal plane of the synthesized product, and I0 is the diffraction intensity of a certain crystal plane of the standard sample of this type of molecular sieve.

[0093] The relative crystallinity data of Examples 1 - 3 and Comparative Examples 1 - 3 are shown in Table 1:

[0094] Table 1

[0095]

[0096] It can be seen from Table 1 that the crystallinity of the molecular sieves prepared by the method for resource utilization of red mud and fly ash to prepare SOD molecular sieves provided by the present invention is higher than that of the currently disclosed methods, indicating that the SOD molecular sieves prepared by the present invention have a higher silicon - aluminum ratio, and the present invention can effectively improve the crystallinity of the molecular sieves.

[0097] To demonstrate the clinical application effect of the present invention, the present invention is proved by clinical experimental research: The compositions of the examples are tested on people of different age groups and different gynecological diseases. After the test, this product is used for antibacterial, cleaning, odor removal and daily care of the female vagina, promoting health. At the same time, on the basis of antibacterial, it can also repair the skin and prevent the recurrence of vaginal inflammation by changing the vaginal environment.

[0098] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above - mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non - restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0099] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing SOD molecular sieve by resource utilization of red mud and fly ash, characterized in that: The following steps are involved: Step 1: Mix red mud and fly ash in a certain proportion and perform acid leaching treatment; Step 2, subjecting the mixture after the acid leaching treatment to an alkali melting treatment; Step 3, subjecting the product after alkali melting treatment to a hydrothermal synthesis reaction; Step 4: The product after the hydrothermal synthesis reaction is subjected to post-treatment such as solid-liquid separation, washing, and drying to obtain a SOD molecular sieve product.

2. According to claim 1, a method for preparing SOD molecular sieve by resource utilization of red mud and fly ash, characterized in that: The step one includes the following steps: Step S101, red mud and fly ash are mixed according to a silicon-aluminum ratio of 1.5-2.5, with the red mud accounting for 60-80% by weight and the fly ash accounting for 20-40% by weight; Step S102, acid leaching the mixed mixture with 3-5 weight percent hydrochloric acid or sulfuric acid solution to reduce the content of soluble sodium in the red mud; Step S103, pre-treating the mixture after acid leaching by washing, filtering, etc. to remove residual acid solution.

3. According to claim 2, a method for preparing SOD molecular sieve by resource utilization of red mud and fly ash, characterized in that: In step S102, the acid leaching temperature is 70-80° C., and the acid leaching time is 1.5-2.5 hours.

4. According to claim 1, a method for preparing SOD molecular sieve by resource utilization of red mud and fly ash, characterized in that: The step 2 includes: Step S201, mixing the pretreated mixture with 48 weight percent of sodium hydroxide solution at an alkali-ash ratio of 1.1 to 1.3; Step S202: subjecting the mixture to a melting reaction to chemically react the silicon and aluminum components in the red mud and fly ash to form a molecular sieve precursor.

5. According to claim 4, a method for preparing SOD molecular sieve by resource utilization of red mud and fly ash, characterized in that: In step S202, the mixture is melt-reacted at a temperature of 600-700° C. for 3-5 hours.

6. The method for preparing SOD molecular sieve by utilizing red mud and fly ash as resources according to claim 1, characterized in that: The step three includes subjecting the molecular sieve precursor to a hydrothermal synthesis reaction, which specifically includes the following steps: Step S301, mixing the molecular sieve precursor and the structure directing agent at a mass ratio of 1:0.2-0.4; Step S302, performing a hydrothermal synthesis reaction at a temperature of 150 to 180°C for 24 to 36 hours to generate SOD molecular sieve crystals.

7. The method for preparing SOD molecular sieve by utilizing red mud and fly ash as resources according to claim 6, characterized in that: The structure directing agent is tetrapropylammonium bromide.

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