Carbon-based molecular sieve and active silico-aluminate prepared from coal gangue, preparation method and application thereof

Abstract

The present application provides a kind of carbon-based molecular sieve and active silicate prepared from coal gangue, preparation method and application, method comprising: step 1, coal gangue is ball milled to obtain coal gangue powder, then the coal gangue powder is placed in carbonization activation deposition integrated rotary furnace, carbonization, activation and deposition are carried out under inert gas atmosphere, to obtain mixed product;Step 2, the mixed product obtained in step 1 is separated in a flotation machine, and carbon-based molecular sieve and active silicate are obtained after drying.The first temperature control component, the second temperature control component and the third temperature control component are arranged between the inner wall of the heat preservation shell and the outer wall of the inner furnace body of the carbonization activation deposition integrated rotary furnace from the tail end to the head end.The present application uses coal gangue as the main raw material, converts the carbon, organic matter and other components contained in the coal gangue into carbon-based molecular sieve, and converts the residual silicon-aluminum phase into active silicate, fully utilizes the main phase of coal gangue, and reduces the waste discharge of the process.

Description

Technical Field

[0001] This invention belongs to the field of materials and relates to the preparation of molecular sieves and zeolites, specifically to a carbon-based molecular sieve and active aluminosilicate prepared from coal gangue, the preparation method and application. Background Technology

[0002] Coal gangue, a major byproduct of coal mining, not only occupies a large amount of land resources but is also prone to spontaneous combustion. Furthermore, the harmful elements in coal gangue, leached by rainwater, pose an ecological threat to soil and water environments, seriously endangering human health. The disposal and utilization of coal gangue mainly focus on energy fuels, building material preparation, chemical products and element extraction, soil conditioning, and mine backfilling. However, it is still necessary to continuously broaden the disposal methods for coal gangue to cope with the ever-increasing production.

[0003] Coal gangue's main chemical components are coal and aluminosilicates, making it an excellent raw material for preparing carbon-based materials and activated aluminosilicates. Carbon-based molecular sieves possess excellent molecular channels, enabling the efficient separation of nitrogen or carbon dioxide from air or flue gas under low-temperature and low-pressure conditions. The raw materials for carbon-based molecular sieve production mainly include carbon, polymers, and biomass. Coal gangue, as a solid waste, is readily available and inexpensive. It is also rich in carbon and organic matter, making it a suitable raw material for synthesizing carbon-based molecular sieves. The aluminosilicate components abundant in coal gangue have the potential to produce cementitious materials, which can be used in building materials, proppant materials, etc. There are many ways to utilize coal gangue, but most of these methods require calcining and activating the raw coal gangue, i.e., preparing it into activated aluminosilicate powder before use. Direct calcination not only increases the cost of coal gangue utilization, but also causes the carbon and organic matter in the coal gangue to burn out completely during the calcination process, releasing harmful gases and wasting resources. Therefore, changing the existing calcination process to first convert the carbon and organic matter in the coal gangue into carbon-based molecular sieves, while simultaneously activating the aluminosilicates in the coal gangue, and finally separating them to obtain carbon-based molecular sieves and activated aluminosilicate powders, has significant environmental and economic benefits. Summary of the Invention

[0004] In view of the defects and shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing carbon-based molecular sieves and activated aluminosilicates using coal gangue and their application in flue gas separation.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing carbon-based molecular sieves and activated aluminosilicates using coal gangue. The method uses coal gangue as raw material and obtains carbon-based molecular sieves and activated aluminosilicates through grinding, carbonization, activation, deposition, separation and drying.

[0007] The present invention also has the following technical features:

[0008] Specifically, the method includes the following steps:

[0009] Step 1: Grind coal gangue into powder, then place the coal gangue powder in a rotary kiln that integrates carbonization, activation and deposition, and perform carbonization, activation and deposition under an inert gas atmosphere to obtain a mixed product;

[0010] Step 2: Separate the mixed product obtained in Step 1 in a flotation machine, and dry it to obtain carbon-based molecular sieve and activated aluminosilicate.

[0011] Furthermore, in step 1, the carbonization temperature is 750–770℃, the carbonization heating rate is 5–15℃ / min, and the carbonization time is 5–10 min; the activation temperature is 780–800℃, the activation time is 30–60 min, the deposition temperature is 700–740℃, the deposition time is 60–90 min, the inert gas is nitrogen, and the flow rate of nitrogen in the integrated carbonization, activation, and deposition rotary furnace is 50 ml / s.

[0012] Furthermore, the method includes the following steps:

[0013] Step 1: Grind coal gangue into 200-mesh coal gangue powder. Then place the coal gangue powder in a rotary furnace that integrates carbonization, activation and deposition. Under the condition of continuous nitrogen gas supply, first heat up to 750℃ at 10℃ / min for carbonization for 10min, then heat up to 780℃ for activation for 30min, and finally cool down to 700℃ for deposition for 60min to obtain a mixture of carbon-based molecular sieve and activated aluminosilicate.

[0014] Step 2: Separate the carbon-based molecular sieve and activated aluminosilicate mixture obtained in Step 1 in a flotation machine, and dry them to obtain carbon-based molecular sieve and activated aluminosilicate.

[0015] Furthermore, the specific surface area of ​​the carbon-based molecular sieve is 345 m². 2 / g~372m 2 / g, with micropore volume of 0.148–0.169 cm³. 3 / g; the 7-day activity index of the active aluminosilicate is greater than 95%, and the 28-day activity index is greater than 105%.

[0016] Furthermore, the integrated carbonization-activation-deposition rotary furnace includes a coaxially fitted insulating outer shell and an inner furnace body; the head and tail ends of the inner furnace body protrude through the side wall of the insulating outer shell respectively; the inner furnace body is capable of rotating relative to the insulating outer shell.

[0017] The front end of the inner furnace body is connected to a gas supply pipe and a water supply pipe, and the rear end of the inner furnace body is connected to a gas venting pipe.

[0018] A first temperature control component, a second temperature control component, and a third temperature control component are provided between the inner wall of the heat-insulating outer shell and the outer wall of the inner furnace, from the tail end to the head end.

[0019] Furthermore, a first flow meter is installed on the gas supply pipeline, and a second flow meter is installed on the water supply pipeline.

[0020] This invention also protects the carbon-based molecular sieves and active aluminosilicates prepared by the above method.

[0021] This invention also protects the application of the carbon-based molecular sieves and activated aluminosilicates prepared by the above method in the preparation of fixed-bed separation devices for enriching nitrogen from flue gas.

[0022] Furthermore, the carbon-based molecular sieve, activated aluminosilicate and polyethylene glycol in the formula are placed in an extruder and pressed into a nitrogen adsorption layer. The nitrogen adsorption layer is then filled into a flue gas fixed bed separation device.

[0023] Of which, by mass percentage, carbon-based molecular sieve accounts for 85.3%, activated aluminosilicate for 14.4%, and polyethylene glycol for 0.3%.

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

[0025] (1) The method of the present invention uses a rotary kiln that integrates carbonization, activation and deposition to achieve three-stage heating of the material in the rotary kiln. It can quickly convert carbon, organic matter and other substances in coal gangue into carbon-based molecular sieves in one step, simplifying the traditional preparation process of carbon-based molecular sieves, shortening the residence time of coal gangue in the rotary kiln, and simultaneously activating the aluminosilicates in coal gangue to obtain a mixture of activated aluminosilicate powder and carbon-based molecular sieves.

[0026] (2) The carbon-based molecular sieve prepared by the method of the present invention has a high specific surface area and micropore volume, and the carbon-based molecular sieve has nitrogen selectivity and can be used in fixed bed separation devices to purify nitrogen with a purity of more than 99.9% from flue gas; the active aluminosilicate powder can be used as a synthetic material for aluminosilicate compounds such as zeolite, ceramics, and concrete.

[0027] (3) The preparation method of the present invention uses coal gangue as the main raw material, converts the carbon, organic matter and other components contained in the coal gangue into carbon-based molecular sieves, and converts the residual silica-alumina phase into active silica-aluminate, making full use of the main phases of coal gangue and reducing the waste discharge of the process.

[0028] (4) The carbon-based molecular sieves and active aluminosilicates prepared by the method of the present invention can be used to prepare a fixed-bed separation device for enriching nitrogen from flue gas. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the integrated carbonization-activation-deposition rotary furnace used in this invention.

[0030] The labels in the diagram represent:

[0031] 1-Insulated outer shell, 2-Inner furnace body, 3-Gas supply pipe, 4-Water supply pipe, 5-Gas venting pipe, 6-First temperature control component, 7-Second temperature control component, 8-Third temperature control component, 9-First flow meter, 10-Second flow meter.

[0032] The technical solution of the present invention will be further described below with reference to the embodiments. Detailed Implementation

[0033] This invention provides a method for preparing carbon-based molecular sieves and activated aluminosilicates using coal gangue. The method uses coal gangue as raw material, and obtains carbon-based molecular sieves and activated silicon phases through grinding, carbonization, activation and deposition. Then, the obtained aluminosilicate phases are chemically excited and hydrothermally seeded to obtain activated aluminosilicates.

[0034] The coal gangue used in this invention comprises the following raw material components, by mass percentage: SiO2 45.1–58.3%, Al2O3 14.2–30.7%, Fe2O3 1.4–8.1%, CaO 0.7–4.7%, MgO 0.5–1.3%, K2O 2.1–2.9%, TiO2 0.4–0.9%, carbon, organic matter, and other trace components 10.5–12.5%, with the total mass percentage of each component being 100%.

[0035] Preferably, the method includes the following steps:

[0036] Step 1: Grind coal gangue into powder, then place the coal gangue powder in a rotary kiln that integrates carbonization, activation and deposition, and perform carbonization, activation and deposition under an inert gas atmosphere to obtain a mixed product;

[0037] Step 2: Separate the mixed product obtained in Step 1 in a flotation machine, and dry it to obtain carbon-based molecular sieve and activated aluminosilicate.

[0038] Preferably, in step 1, the carbonization temperature is 750–770°C, the carbonization heating rate is 5–15°C / min, and the carbonization time is 5–10 min; the activation temperature is 780–800°C, the activation time is 30–60 min, the deposition temperature is 700–740°C, the deposition time is 60–90 min, the inert gas is nitrogen, and the flow rate of nitrogen in the integrated carbonization, activation, and deposition rotary furnace is 50 ml / s.

[0039] Preferably, the specific surface area of ​​the carbon-based molecular sieve is 345 m².2 / g~372m 2 / g, with micropore volume of 0.148–0.169 cm³. 3 / g; the 7-day activity index of the active aluminosilicate is greater than 95%, and the 28-day activity index is greater than 105%.

[0040] Preferably, the method is implemented by an integrated carbonization-activation-deposition rotary furnace, which includes a coaxially fitted insulating outer shell and an inner furnace body; the head and tail ends of the inner furnace body protrude through the side wall of the insulating outer shell respectively; the inner furnace body can rotate relative to the insulating outer shell; wherein the internal structure of the inner furnace body is the same as that of existing rotary furnaces.

[0041] The front end of the inner furnace body is connected to a gas supply pipe and a water supply pipe, and the rear end of the inner furnace body is connected to a gas venting pipe.

[0042] A first temperature control component, a second temperature control component, and a third temperature control component are provided between the inner wall of the heat-insulating outer shell and the outer wall of the inner furnace, from the tail end to the head end.

[0043] Preferably, a first flow meter is installed on the gas supply pipeline, and a second flow meter is installed on the water supply pipeline.

[0044] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0045] Example 1

[0046] Following the above technical solution, this embodiment discloses a method for preparing carbon-based molecular sieves and activated aluminosilicates using coal gangue.

[0047] Includes the following steps:

[0048] Step 1: Grind the coal gangue into 200-mesh powder, then place the coal gangue powder in a rotary kiln integrating carbonization, activation, and deposition. Figure 1 As shown;

[0049] Step 2: Start the integrated carbonization, activation and deposition rotary furnace and turn on the first temperature control component 6, the second temperature control component 7 and the third temperature control component 8 to heat the different areas inside the integrated carbonization, activation and deposition rotary furnace to the temperature required for the carbonization, activation and deposition process of coal gangue. During this process, nitrogen gas is continuously introduced into the rotary furnace.

[0050] In this embodiment, the first temperature control component 6, the second temperature control component 7, and the third temperature control component 8 have the same structure, each including a heating resistance wire and a temperature controller connected to the heating resistance wire.

[0051] Step 3: Separate the carbon-based molecular sieve and activated aluminosilicate mixture obtained in Step 2 in a flotation machine, and dry them to obtain carbon-based molecular sieve and activated aluminosilicate powder.

[0052] In step 2, the carbonization temperature is 750℃, the heating rate is 10℃ / min, the carbonization time is 10min, the activation temperature is 780℃, the activation time is 30min, the deposition temperature is 700℃, the deposition aid is nitrogen, and the flow rate of nitrogen in the integrated carbonization, activation and deposition rotary furnace is 50ml / s, and the deposition time is 60min.

[0053] In step 3, the flotation machine meets the requirements of JB / T3686.1-1999, and the drying temperature is 60℃.

[0054] In this embodiment, the yield, specific surface area, micropore volume and nitrogen selectivity of carbon-based molecular sieves are shown in Table 1, and the yield and activity index of activated aluminosilicate powder are shown in Table 2. The activity index was measured in accordance with GB / T17671-1999.

[0055] Example 2

[0056] This embodiment discloses a method for preparing coal gangue-based carbon-based molecular sieves and activated silicate powders. The steps and raw material components of the preparation method are the same as those in Example 1. The difference is that the carbonization temperature in this embodiment is 760℃, the heating rate is 10℃ / min, the carbonization time is 5min, the activation temperature is 790℃, the activation time is 30min, the deposition temperature is 730℃, and the deposition time is 60min. The separation process after preparation is also the same as that in Example 1.

[0057] In this embodiment, the yield, specific surface area, micropore volume and nitrogen selectivity of carbon-based molecular sieves are shown in Table 1, and the yield and activity index of activated aluminosilicate powder are shown in Table 2. The activity index was measured in accordance with GB / T17671-1999.

[0058] Example 3

[0059] This embodiment discloses a method for preparing coal gangue-based carbon-based molecular sieves and activated silicate powders. The steps and raw material components of the preparation method are the same as those in Example 1, except that: in this embodiment, the carbonization temperature is 770℃, the heating rate is 10℃ / min, the carbonization time is 5min, the activation temperature is 800℃, the activation time is 30min, the deposition temperature is 740℃, and the deposition time is 60min.

[0060] In this embodiment, the yield, specific surface area, micropore volume and nitrogen selectivity of carbon-based molecular sieves are shown in Table 1, and the yield and activity index of activated aluminosilicate powder are shown in Table 2. The activity index was measured in accordance with GB / T17671-1999.

[0061] Example 4

[0062] This embodiment discloses a method for preparing coal gangue-based carbon-based molecular sieves and activated silicate powders. The steps and raw material components of the preparation method are the same as those in Example 1, except that: in this embodiment, the carbonization temperature is 750℃, the heating rate is 10℃ / min, the carbonization time is 15min, the activation temperature is 780℃, the activation time is 60min, the deposition temperature is 720℃, and the deposition time is 90min.

[0063] In this embodiment, the yield, specific surface area, micropore volume and nitrogen selectivity of the prepared carbon-based molecular sieve are shown in Table 1, and the yield and activity index of the activated aluminosilicate powder are shown in Table 2. The activity index was measured in accordance with GB / T17671-1999.

[0064] Comparative Example 1

[0065] This comparative example uses existing molecular sieves for nitrogen separation, such as CMS molecular sieves, and existing S105 mineral powder as comparative materials, and compares them with the products obtained in Examples 1 to 4 of the present invention. The comparison results are shown in Tables 1 and 2.

[0066]

[0067] Table 1. Parameters of carbon-based molecular sieves in Examples 1-4 and comparative examples

[0068] Sample Active powder yield / wt% 7d activity index / % 28d activity index / % Example 1 87.3 105 116 Example 2 85.6 102 109 Example 3 83.9 100 106 Example 4 81.2 96 112 S105 mineral powder - 95 105

[0069] Table 2. Yield and activity index of active aluminosilicate powder in Examples 1-4 and comparative examples.

[0070] The comparison results above show that:

[0071] Since the pore structure of carbon-based molecular sieves is independent of yield, and the deposition aids in the deposition process play a decisive role, the process conditions for preparing carbon-based molecular sieves significantly affect their yield, while having a relatively small impact on their specific surface area and pore volume. Overall, compared to commercially available CMS molecular sieves, the carbon-based molecular sieve prepared from coal gangue using the method of this invention exhibits superior specific surface area, micropore volume, and nitrogen selectivity.

[0072] Because excessively high temperatures and times can cause the aluminosilicate phase to overheat and lose some of its activity, different processes have a significant impact on the activity index of activated aluminosilicate powders. The higher the process temperature and the longer the time, the less conducive it is to the activation of the aluminosilicate phase in coal gangue.

[0073] The carbon-based molecular sieves and activated aluminosilicates prepared by the method of the present invention can be used to prepare fixed-bed separation devices for enriching nitrogen from flue gas.

[0074] Specifically, the carbon-based molecular sieve, activated aluminosilicate powder, and polyethylene glycol in the specified amounts are placed in an extruder and pressed into a nitrogen adsorption layer. The resulting nitrogen adsorption layer is then filled into the bottom of a flue gas fixed bed separation device. The carbon-based molecular sieve accounts for 85.3% of the total mass, the activated aluminosilicate powder accounts for 14.4%, and the polyethylene glycol accounts for 0.3%.

[0075] The active aluminosilicate powder prepared by the method of this invention can also be used as a carrier for carbon molecular sieves, as well as a raw material for the synthesis of aluminosilicate compounds such as zeolites, ceramics, and concrete.

[0076] In summary, the method of this invention makes full use of the carbon and organic matter in coal gangue, transforming it into high-value-added materials. More importantly, while carbon-based molecular sieves are being generated, the residual silica-alumina phase in the coal gangue is thermally activated to form active aluminosilicate powder, achieving the activity of S105 ore powder and realizing the full utilization of various phases of coal gangue.

[0077] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0079] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for preparing carbon-based molecular sieves and activated aluminosilicates using coal gangue, characterized in that, This method uses coal gangue as raw material, and obtains carbon-based molecular sieves and activated aluminosilicates through grinding, carbonization, activation, deposition, separation and drying. The method includes the following steps: Step 1: Grind coal gangue into powder, then place the coal gangue powder in a rotary kiln that integrates carbonization, activation and deposition, and perform carbonization, activation and deposition under an inert gas atmosphere to obtain a mixed product; Step 2: Separate the mixed product obtained in Step 1 in a flotation machine, and dry it to obtain carbon-based molecular sieve and activated aluminosilicate; In step 1, the carbonization temperature is 750~770˚C, the carbonization heating rate is 5~15˚C / min, and the carbonization time is 5~10min; the activation temperature is 780~800˚C, the activation time is 30~60min, the deposition temperature is 700~740˚C, the deposition time is 60~90min, the inert gas is nitrogen, and the flow rate of nitrogen in the integrated carbonization, activation, and deposition rotary furnace is 50ml / s.

2. The method as described in claim 1, characterized in that, The method includes the following steps: Step 1: Grind coal gangue into 200-mesh coal gangue powder. Then, place the coal gangue powder in a rotary furnace that integrates carbonization, activation, and deposition. Under continuous nitrogen gas supply, first heat up to 750℃ at 10℃ / min for 10 min, then heat up to 780℃ for 30 min for activation, and finally cool down to 700˚C for 60 min for deposition to obtain a mixture of carbon-based molecular sieve and activated aluminosilicate. Step 2: Separate the carbon-based molecular sieve and activated aluminosilicate mixture obtained in Step 1 in a flotation machine, and dry them to obtain carbon-based molecular sieve and activated aluminosilicate.

3. The method as described in claim 1, characterized in that, The specific surface area of ​​the carbon-based molecular sieve is 345 m². 2 / g~372m 2 / g, with micropore volumes of 0.148~0.169cm³. 3 / g; the 7-day activity index of the active aluminosilicate is greater than 95%, and the 28-day activity index is greater than 105%.

4. The method as described in claim 1, characterized in that, The integrated carbonization and activation deposition rotary furnace includes a coaxially fitted heat-insulating outer shell (1) and an inner furnace body (2); the head and tail ends of the inner furnace body (2) protrude through the side wall of the heat-insulating outer shell (1); the inner furnace body (2) can rotate relative to the heat-insulating outer shell (1). The inner furnace body (2) is connected to a gas supply pipe (3) and a water supply pipe (4) at its head end, and to a gas venting pipe (5) at its tail end. The inner wall of the heat-insulating shell (1) and the outer wall of the inner furnace body (2) are provided with a first temperature control component (6), a second temperature control component (7) and a third temperature control component (8) from the tail end to the head end.

5. The method as described in claim 4, characterized in that, A first flow meter (9) is installed on the gas supply pipe (3), and a second flow meter (10) is installed on the water supply pipe (4).

6. The carbon-based molecular sieve and activated aluminosilicate prepared by the method according to any one of claims 1 to 4.

7. The application of the carbon-based molecular sieve and activated aluminosilicate prepared by the method according to any one of claims 1 to 4 in the preparation of a fixed-bed separation device for enriching nitrogen from flue gas.

8. The application as described in claim 7, characterized in that, The carbon-based molecular sieve, activated aluminosilicate and polyethylene glycol in the formula are placed in an extruder and pressed into a nitrogen adsorption layer. The nitrogen adsorption layer is then filled into a flue gas fixed bed separation device. Of which, by mass percentage, carbon-based molecular sieve accounts for 85.3%, activated aluminosilicate for 14.4%, and polyethylene glycol for 0.3%.

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