Mineral-based composite material as well as preparation method and application thereof

Abstract

The invention provides a mineral-based composite material as well as a preparation method and application thereof, and belongs to the technical field of flue gas heavy metal pollution prevention and control. The mineral-based composite material provided by the invention comprises a mineral matrix and a sulfur source and / or a selenium source loaded on the surface of the mineral matrix and in pores of the mineral matrix. The mineral matrix is used as a carrier, and the mineral matrix has the characteristics of low cost, no toxicity, large specific surface area, good biocompatibility and strong chemical thermal stability, so that the preparation cost of the composite material is reduced; when the mineral-based composite material prepared by taking selenium and sulfur as active sites is used for demercuration, the sulfur can convert mercury into non-toxic and stable HgS, so that the defect of secondary release after demercuration is avoided; meanwhile, selenium is used for modifying a sulfur source, and HgSe is generated, so that gaseous mercury can be further solidified and attenuated, and the ecological benefit is obvious.

Description

Technical Field

[0001] The present invention belongs to the technical field of smoke heavy metal pollution prevention and control, and particularly relates to a mineral-based composite material and a preparation method and application thereof. Background Art

[0002] Coal-fired power plant gaseous mercury (Hg 0 ) is volatile and difficult to dissolve in water, and is currently the focus of mercury pollution control in coal-fired flue gas. The emission technology of elemental mercury in coal-fired flue gas can be mainly divided into mercury removal before combustion, mercury removal during combustion and mercury removal after combustion. Mercury removal before combustion, that is, reducing the mercury content by washing coal and heat treatment before coal combustion, has the disadvantages of high cost and the need for further treatment of mercury-containing wastewater generated during the treatment process; mercury removal during combustion mainly involves spraying adsorbents in the furnace, and the operating environment is harsh. Currently, there are few studies at home and abroad. The control of elemental mercury pollution in flue gas at home and abroad mainly focuses on the adsorption and removal of elemental mercury in flue gas after combustion. In order to achieve efficient mercury removal, activated carbon injection technology is used in the existing technology, but due to its limited adsorption kinetics, secondary release and environmental toxicity problems, it is not suitable for long-term application. Summary of the Invention

[0003] The present invention aims to provide a mineral-based composite material, a preparation method thereof, and an application thereof. The mineral-based composite material provided by the present invention uses a mineral as a carrier and a sulfur source and a selenium source as active substances, is low in cost, and is non-toxic. The mineral-based composite material provided by the present invention is used for mercury removal, has low secondary release and environmental risks, and can achieve the solidification and detoxification of industrial mercury.

[0004] In order to achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0005] A mineral-based composite material comprises a mineral matrix and a sulfur source and / or a selenium source loaded on the surface of the mineral matrix and in its pores.

[0006] Preferably, the mineral matrix comprises one or more of sepiolite, halloysite, attapulgite and zeolite;

[0007] The sulfur source includes metal sulfide or elemental sulfur;

[0008] The selenium source includes one or more of elemental selenium, selenite and selenate.

[0009] Preferably, the molar ratio of the mass of the mineral matrix to the sulfur source is 0.5-1 g: 0.025-0.05 mol;

[0010] The molar ratio of the mass of the mineral matrix to the selenium source is 0.5-1g:0.001-0.03mol.

[0011] The present invention also provides a method for preparing the mineral-based composite material described in the above technical solution, comprising the following steps:

[0012] The sulfur source and / or selenium source and the mineral matrix are subjected to mechanical ball milling to obtain the mineral-based composite material.

[0013] Preferably, the conditions of the mechanical ball milling include: a time of 1 to 6 hours and a rotation speed of 100 to 400 r / min;

[0014] The ball milling aid is an ethanol aqueous solution and / or an acetic acid aqueous solution, and the liquid-solid ratio of the ball milling aid to the material is 0.1-0.5 mL: 0.5-1.5 g;

[0015] The grinding balls are made of stainless steel or zirconium dioxide, with a particle size of 5 to 15 mm and a ball-to-material ratio of 5 to 20:1.

[0016] Preferably, the method further comprises calcining and acid leaching the mineral matrix in sequence.

[0017] Preferably, the calcination temperature is 450-600° C. and the calcination time is 1.5-4 hours.

[0018] Preferably, the reagent used for the acid leaching is one of hydrochloric acid and / or nitric acid.

[0019] The present invention also provides the use of the mineral-based composite material described in the above technical solution or the mineral-based composite material prepared by the preparation method described in the above technical solution in gas-phase mercury removal.

[0020] Preferably, the temperature in the gas phase mercury removal is 90-150° C., the gas flow rate is 300-1000 mL / min, and the nitrogen content is 25-30 wt %.

[0021] The present invention provides a mineral-based composite material, comprising a mineral matrix and a sulfur source and / or selenium source supported on the surface and within the pores of the mineral matrix. The present invention uses the mineral matrix as a carrier. The mineral matrix is ​​characterized by low cost, non-toxicity, large specific surface area, good biocompatibility, and strong chemical and thermal stability. Furthermore, the mineral surface typically contains a large number of hydroxyl groups and has mesopores or macropores, serving as a natural adsorption material and carrier dispersant. This effectively exposes active substances, uniformly dispersing and fixing them on the carrier surface, further reducing the preparation cost of the composite material. The mineral-based composite material, prepared with selenium and sulfur as active sites, is used for mercury removal. The sulfur can convert mercury into non-toxic, stable HgS, avoiding the drawback of secondary release after mercury removal. Furthermore, the present invention uses selenium to modify the sulfur source, converting mercury into HgSe. Based on the antagonistic effect of selenium and mercury, this further solidifies and detoxifies gaseous mercury, and improves the poor temperature tolerance of selenide, resulting in significant economic benefits.

[0022] The present invention also provides a method for preparing the mineral-based composite material described in the above technical solution. The mineral-based composite material is prepared only by mechanical ball milling, which has a short preparation cycle and avoids the use of additives (such as metal salts) in the synthesis process, greatly reducing the material preparation cost. The synthesized mineral-based composite material can be produced on a large scale and has broad application prospects in the field of mercury. The adsorption capacity of the mineral-based composite material prepared by the present invention exceeds 30.05 mg·m -3 The adsorption rate can reach up to 100%. Compared with traditional activated carbon materials, the adsorption kinetics performance has been greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is an experimental device for testing the mercury removal performance of the present invention;

[0025] Figure 2 This is a diagram of the mechanical ball milling process of the present invention;

[0026] Figure 3 FTIR characterization diagram and XRD spectrum of the mineral-based composite materials obtained in Example 1 and Example 2;

[0027] Figure 4 This is a graph showing the mercury removal efficiency of the mineral-based composite material obtained in Example 1;

[0028] Figure 5 This is a graph showing the mercury removal efficiency of the mineral-based composite material obtained in Example 2;

[0029] Figure 6 Graph showing the mercury removal efficiency of FeS-ATP obtained in Example 1, 0.005Se@FeS-ATP obtained in Example 2, ZnCl2-AC, and H2SO4-AC;

[0030] Figure 7 The XPS spectra and water contact angle diagrams of ATP, FeS-ATP obtained in Example 1, and 0.005Se@FeS-ATP obtained in Example 2 are shown;

[0031] Figure 8 This is a graph showing the mercury removal efficiency of 0.005Se@FeS-ATP obtained in Example 2 under different temperature conditions;

[0032] Figure 9 This is a graph showing the mercury removal efficiency of 0.005Se@FeS-ATP obtained in Example 2 under different space velocity conditions;

[0033] Figure 10 This is a graph showing the mercury removal efficiency of 0.005Se@FeS-ATP obtained in Example 2 under different flue gas conditions. DETAILED DESCRIPTION

[0034] The invention provides a mineral-based composite material, comprising a mineral matrix and a sulfur source and / or a selenium source loaded on the surface of the mineral matrix and in its pores.

[0035] In the present invention, unless otherwise specified, all preparation raw materials are preferably commercially available products well known to those skilled in the art.

[0036] In the present invention, the mineral matrix includes one or more of sepiolite (Sep), halloysite (HNTs), attapulgite (ATP) and zeolite (Zeolite). In a specific embodiment, the mineral matrix may be attapulgite.

[0037] In the present invention, the sulfur source includes metal sulfide or elemental sulfur. In a specific embodiment, it can be metal sulfide. The metal sulfide can be FeS, CuS, ZnS or MoS. The selenium source includes one or more of elemental selenium, selenite and selenate. In a specific embodiment, the elemental selenium can be selenium pills, the selenite can be sodium selenite, and the selenate can be sodium selenate.

[0038] In the present invention, the molar ratio of the mass of the mineral matrix to the sulfur source can be 0.5-1g:0.025-0.05mol, and in specific embodiments, it can be 0.8g:0.025mol, 1g:0.03mol or 1g:0.04mol; the molar ratio of the mass of the mineral matrix to the selenium source can be 0.5-1g:0.001-0.03mol, and in specific embodiments, it can be 1g:0.005mol, 1g:0.008mol, 1g:0.01mol or 1g:0.03mol.

[0039] In the present invention, the mineral-based composite material may be FeS-ATP, CuS-ATP, ZnS-ATP, S-ATP, Se@FeS-ATP, Se@CuS-ATP, Se@ZnS-ATP or Se@S-ATP.

[0040] The present invention also provides a method for preparing the mineral-based composite material described in the above technical solution, comprising the following steps:

[0041] The sulfur source and / or selenium source and the mineral matrix are subjected to mechanical ball milling to obtain the mineral-based composite material.

[0042] In the present invention, when the mineral matrix is ​​loaded with a sulfur source and a selenium source, the sulfur source and the mineral matrix are first mechanically ball-milled to obtain a precursor; and the precursor and the selenium source are mechanically ball-milled to obtain the mineral-based composite material.

[0043] In the present invention, the conditions for the mechanical ball milling include: the time can be 1 to 6 hours, in a specific embodiment, it can be 2 hours, 3 hours or 5 hours; the rotation speed can be 100 to 400 r / min, in a specific embodiment, it can be 100 r / min, 200 r / min, 300 r / min or 400 r / min; the mechanical ball milling is carried out at room temperature.

[0044] In the present invention, the ball milling aid can be an ethanol aqueous solution and / or an acetic acid aqueous solution. In a specific embodiment, it can be an ethanol aqueous solution or an acetic acid aqueous solution. The liquid-solid ratio of the ball milling aid to the material can be 0.1-0.5 mL:0.5-1.5 g. In a specific embodiment, it can be 0.5 mL:0.5 g, 0.5 mL:1 g or 0.5 mL:1.5 g.

[0045] In the present invention, the material of the grinding balls can be stainless steel or zirconium dioxide, and the particle size of the grinding balls can be 5-15 mm, and in specific embodiments, can be 8 mm, 10 mm or 12 mm; the ball-to-material ratio can be 5-20:1, and in specific embodiments, can be 9:1, 11:1, 15:1 or 18:1.

[0046] The present invention further includes sequentially calcining and acid leaching the mineral matrix; the calcination temperature may be 450-600°C, and in specific embodiments, may be 450°C, 500°C, or 600°C; the calcination time may be 1.5-4 hours, and in specific embodiments, may be 2 hours, 3 hours, or 4 hours; the heating rate to the desired calcination temperature may be 8-10°C / min. The calcination process preferably includes sieving the mineral matrix; the sieving mesh size may be 80-140 mesh, and in specific embodiments, may be 80, 100, 120, or 140 mesh.

[0047] In the present invention, the acid reagent used for the acid leaching may be hydrochloric acid or nitric acid; the concentration of the hydrochloric acid may be 5 to 10 wt%, and in a specific embodiment, may be 7 wt% or 9 wt%; the acid leaching includes mixing the mineral matrix and the acid reagent and impregnating them; the mixing may be stirred for 3 to 5 hours; and the impregnation time may be 12 to 24 hours.

[0048] In the present invention, the acid leaching further comprises washing and drying the obtained product; the washing may be water washing, and the present invention does not limit the number of washings, as long as the product is washed until neutral; the drying temperature may be 110-120° C., and the present invention does not limit the drying time, as long as the product is dried until constant weight.

[0049] In the present invention, mechanical ball milling also includes drying and grinding the obtained product; the drying can be freeze drying, and in a specific embodiment it can be vacuum freeze drying; the drying time can be 6 to 8 hours; the present invention has no special limitation on the grinding, and in a specific embodiment, the mineral-based composite material is ground to a particle size of 0.5 to 10 μm.

[0050] The present invention also provides the use of the mineral-based composite material described in the above technical solution or the mineral-based composite material prepared by the preparation method described in the above technical solution in gas-phase mercury removal.

[0051] In the present invention, the gas-phase mercury removal process includes the following steps: 1) checking airtightness and powering on the heating belt to prevent mercury vapor condensation; 2) weighing the mineral-based composite material described in the above technical solution and placing it into a sample support column; 3) turning on a Lumex-915 portable mercury analyzer, first introducing nitrogen to set a nitrogen content background value, then adjusting the gas flow rate and mercury flow rate, and testing the mercury removal performance of the sample; and 4) after the test is completed, saving and analyzing the sample.

[0052] In the present invention, the temperature in the gas phase mercury removal can be 90-150° C., and in a specific embodiment, can be 110, 120 or 130° C.; the gas flow rate can be 300-1000 mL / min, and the nitrogen content can be 25-30 wt %.

[0053] In order to further illustrate the present invention, the mineral-based composite material provided by the present invention, its preparation method and application are described in detail below with reference to the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] The attapulgite was evenly spread on the sieve and passed through a 140-mesh sieve. 10 g of the sieved attapulgite was placed in a muffle furnace for calcination. The temperature was raised from room temperature to 500 ° C at a rate of 10 ° C / min. The calcination was carried out at 500 ° C for 3 hours. After cooling, the attapulgite was transferred to a beaker, 250 mL of 10 wt% HCl was added, and the mixture was stirred for 3 hours and then immersed for 24 hours. The mixture was washed with deionized water until neutral, and dried in an oven at 110 ° C to constant weight. The mixture was taken out and ground to obtain pretreated attapulgite powder;

[0056] Weigh 0.05 mol of FeS, ZnS, CuS and elemental S respectively, pour them into a ball mill jar with 1 g of the pretreated attapulgite powder, mix them evenly with a glass rod, soak them with 0.5 mL of ethanol solution, and add stainless steel balls (particle size of 10 mm) into the jar at a ball-to-material mass ratio of 11:1; Figure 2 The ball milling process shown was performed by mechanical ball milling, and the planetary ball mill program was set as follows: time 1 h, rest time 0.5 h, 2 cycles; the speed was 400 r / min. After the ball milling was completed, it was moved to a vacuum freeze drying box and frozen for 6 h. After the above steps were completed, the sample was taken out and ground with an agate mortar to obtain mineral-based composite materials, which were respectively recorded as FeS-ATP, ZnS-ATP, CuS-ATP, and S-ATP.

[0057] Example 2

[0058] 0.001 mol, 0.005 mol, 0.01 mol and 0.03 mol of selenium powder were weighed respectively, and poured into a ball mill jar with 1 g of the FeS-ATP mineral-based composite material prepared in Example 1, mixed evenly with a glass rod, soaked with 0.5 mL of ethanol solution, and stainless steel balls (particle size 10 mm) were added to the jar at a ball-to-material mass ratio of 11:1; the planetary ball mill program was set as follows: time 1 h, rest time 0.5 h, and cycle 2 times; the speed was 400 r / min. After the ball milling was completed, it was moved to a vacuum freeze drying oven and frozen for 6 h. After the above steps were completed, the sample was taken out and ground with an agate mortar to obtain mineral-based composite materials, which were respectively recorded as 0.001Se@FeS-ATP, 0.005Se@FeS-ATP, 0.01Se@FeS-ATP and 0.03Se@FeS-ATP.

[0059] Figure 3 FTIR characterization diagrams and XRD spectra of the mineral-based composite materials obtained in Example 1 and Example 2, wherein 1) A is the FTIR characterization diagram of ATP, B is the FTIR characterization diagram of FeS, C is the FTIR characterization diagram of FeS-ATP, and D is the FTIR characterization diagram of 0.005Se@FeS-ATP; 2) is the XRD spectra of ATP, FeS, and the mineral-based composite materials prepared in Example 1 and Example 2. Figure 3 It can be seen that the stretching bond and vibration peaks of ATP and FeS and their characteristic peak phases are found on the FeS-ATP surface, proving that Example 1 of the present invention loaded FeS on the ATP surface by mechanical ball milling; at the same time, it can be found that the incorporation of selenium triggers the FeS-ATP to have a high molecular weight distribution in the range of 500-900 cm -1 The deformation vibration proves that Se is successfully loaded, and the XRD spectrum also proves that the diffraction peak at θ=28 is gradually covered with the increase of selenium content, proving that the mineral-based composite material of Example 2 is successfully prepared.

[0060] Test Example 1

[0061] 50 mg of the mineral-based composite materials prepared in Example 1 and Example 2 were weighed and placed in a simulated fixed-bed reactor. Gaseous elemental mercury was generated through a mercury permeation tube. The elemental mercury concentration at the reactor inlet and outlet was monitored in real time using a Lumex-915 mercury analyzer. The flow rate and proportion of various component gases were controlled to simulate real flue gas conditions. The total gas flow rate was 0.5 L min -1 , the initial mercury concentration was 300 μg·m -3 , the adsorption temperature is 90℃ and 150℃, and mercury is removed under pure nitrogen conditions. The mercury removal efficiency is shown below.

[0062] Mercury removal performance test device Figure 1 As shown, 1-gas distribution device, wherein 1-1 is a gas distribution device for SO2, NO, CO2 and O2, 1-2 is a carrier gas N2 gas distribution device, and 1-3 is a shielding gas N2 gas distribution device; 2-fixed bed, wherein 2-1 is an adsorbent; 3-gas mixing device, 4-mercury generator, 5-water vapor generating device, 6-mercury analyzer, 7-NaOH solution, 8-exhaust gas treatment device, 9-gas control valve, 10-heating belt, 11-temperature controller, wherein 11-1 is a fixed bed temperature controller, and 11-2 is a heating belt temperature controller;

[0063] Figure 4 The mercury removal efficiency diagram of the mineral-based composite material obtained in Example 1 is shown in FIG. Figure 4 As can be seen, the CuS-ATP composite material achieved the highest mercury removal efficiency, reaching 100%, at both 90°C and 150°C. The FeS-ATP composite material had a relatively low efficiency (81%). This is due to the FeS purity of 60.00%-72.00%, which leaves some FeS unactivated, while the other three sulfides all had 99.99% purity. Given the relatively high price of CuS and ZnS, while FeS is relatively inexpensive, the FeS-ATP composite material, with its relatively high mercury removal efficiency, was ultimately selected for subsequent experimental studies.

[0064] Figure 5 The mercury removal efficiency diagram of the mineral-based composite material obtained in Example 2 is shown in FIG. Figure 5 As can be seen, the mercury removal efficiency of the composite materials all reached over 90%, with 0.005Se@FeS-ATP and 0.01Se@FeS-ATP achieving the highest efficiency (100%). This indicates that the mercury removal efficiency of the materials gradually increases with increasing Se content. Notably, the mercury removal efficiency of 0.03Se@FeS-ATP was poor. This is attributed to the fact that excessive Se content causes aggregation, which reduces the exposure of active species and leads to a decrease in the material's mercury removal performance.

[0065] Figure 6 The mercury removal efficiency diagram of FeS-ATP obtained in Example 1, 0.005Se@FeS-ATP obtained in Example 2, ZnCl2-AC and H2SO4-AC is shown in FIG. Figure 6 It can be seen that the removal efficiency of FeS-ATP and 0.005Se@FeS-ATP prepared in the present invention is higher than that of ZnCl2-AC activated carbon adsorbent and much higher than that of conventional commercial H2SO4-AC, and has excellent mercury removal performance.

[0066] Figure 7 The XPS spectra and water contact angle diagrams of ATP, FeS-ATP obtained in Example 1 and 0.005Se@FeS-ATP after use obtained in Example 2, wherein 1) is the XPS spectra and 2) is the water contact angle diagram; Figure 7 As can be seen, the mercury adsorbed by the 0.005Se@FeS-ATP obtained in Example 2 exists primarily in the form of HeSe (101.68 eV) and HgS (102.48 eV). The high adsorption capacity is attributed to the presence of selective active sites of *S and *Se on the material's surface. Furthermore, Figure 2) shows that the FeS-ATP and 0.005Se@FeS-ATP prepared by the present invention have enhanced water resistance. Comprehensive analysis of flue gas performance reveals that the composite material exhibits acid and moisture resistance and achieves solidification and detoxification of gaseous mercury.

[0067] Test Example 2

[0068] The effect of temperature on the mercury removal efficiency of the mineral-based composite material prepared by the present invention is as follows:

[0069] The 0.005Se@FeS-ATP obtained in Example 2 was tested at 30°C, 50°C, 90°C, 120°C, 150°C and 200°C, with a total gas flow rate of 500 mL / min (mercury: 150 mL / min, nitrogen: 350 mL / min) and a dosage of 50 mg. The results are shown below.

[0070] Figure 8 The mercury removal efficiency diagram of 0.005Se@FeS-ATP under different temperature conditions obtained in Example 2 is shown in FIG. Figure 8The mercury removal efficiency of 0.005Se@FeS-ATP is below 90% at 30°C and 50°C. It exceeds 95% between 90 and 150°C. At 200°C, the efficiency is relatively low, at only 76.65%. This is attributed to the fact that at lower temperatures, molecular kinetic energy is lower, leading to effective intermolecular collisions and slower mercury adsorption. Within a certain range, increasing temperature intensifies molecular thermal motion, increasing the frequency of contact between mercury and 0.005Se@FeS-ATP per unit time. This promotes effective collisions between the material and mercury, accelerating the adsorption rate and improving the adsorption efficiency of 0.005Se@FeS-ATP. However, above a certain temperature threshold, high temperatures may damage the internal structure of the composite material or desorb adsorbed mercury, reducing the mercury removal efficiency. Furthermore, the temperature range of 90 to 150°C is the optimal temperature range for mercury removal. Within this range, while the mercury removal efficiency of 0.005Se@FeS-ATP decreases with increasing temperature, its overall efficiency remains above 95%, confirming the wide applicability, numerous active sites, and strong adsorption capacity of 0.005Se@FeS-ATP.

[0071] Test Example 3

[0072] The effect of gas flow rate on the mercury removal efficiency of the mineral-based composite material prepared by the present invention is analyzed in the following steps:

[0073] The 0.005Se@FeS-ATP obtained in Example 2 was tested at a total gas flow rate of 300 mL / min, 500 mL / min, 700 mL / min, and 1000 mL / min, temperature: 150°C, time: 30 min, dosage: 50 mg, and the test results are shown below.

[0074] Figure 9 This is the mercury removal efficiency diagram of 0.005Se@FeS-ATP under different space velocity conditions obtained in Example 2. Figure 9 As can be seen, the performance of 0.005Se@FeS-ATP in adsorbing flue gas mercury gradually decreases with increasing total airflow. At airflow rates of 300 mL / min and 500 mL / min, the average mercury removal efficiency of 0.005Se@FeS-ATP exceeds 95%. However, when the airflow rate increases to 700 mL / min, the efficiency decreases slightly, and at a flow rate of 1000 mL / min, the efficiency is only 83.72%. This indicates that increasing the airflow rate reduces the mercury removal efficiency of 0.005Se@FeS-ATP. This is primarily due to the fact that the increased space velocity reduces the contact time between mercury and the material, hindering the reaction. However, actual flue gas flow rates are much lower than those simulated in the laboratory, indicating that 0.005Se@FeS-ATP is suitable for controlling mercury in real flue gases.

[0075] Test Example 4

[0076] The effect of flue gas on the mercury removal efficiency of the mineral-based composite material prepared by the present invention is analyzed in the following steps:

[0077] The 0.005Se@FeS-ATP obtained in Example 2 was tested under two flue gas conditions: pure nitrogen and waste incineration flue gas, temperature: 150°C, time: 30 min, dosage: 50 mg. The pure nitrogen condition was a total gas flow rate of 500 mL / min; the waste incineration flue gas condition was a total gas flow rate of 500 mL / min (Hg 0 : 150mL / min, N2: 212.5mL / min, CO2: 60mL / min, HCl: 50mL / min, O2: 25mL / min, SO2: 2mL / min, NO: 0.5mL / min), calculate the mean of the obtained data, and the test results are as follows Figure 10 shown.

[0078] Figure 10 This is the mercury removal efficiency diagram of 0.005Se@FeS-ATP under different flue gas conditions obtained in Example 2. Figure 10 The results show that the mercury removal efficiency of 0.005Se@FeS-ATP in waste incineration flue gas decreased by 4.57% compared to pure nitrogen conditions. Despite this, the efficiency still reached over 92%, indicating that 0.005Se@FeS-ATP has good adsorption performance. This can be attributed to the large number of active sites (S, Se, O, Fe) on the surface of 0.005Se@FeS-ATP. The presence of these elements facilitates the selective adsorption of mercury.

[0079] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A mineral-based composite material, characterized in that: The invention comprises a mineral matrix and a sulfur source and / or a selenium source loaded on the surface of the mineral matrix and in the pores thereof.

2. The preparation method according to claim 1, characterized in that The mineral matrix includes one or more of sepiolite, halloysite, attapulgite and zeolite; The sulfur source includes metal sulfide or elemental sulfur; The selenium source includes one or more of elemental selenium, selenite and selenate.

3. The mineral-based composite material according to claim 1, characterized in that The molar ratio of the mass of the mineral matrix to the sulfur source is 0.5-1 g: 0.025-0.05 mol; The molar ratio of the mass of the mineral matrix to the selenium source is 0.5-1 g: 0.001-0.03 mol.

4. The method for preparing the mineral-based composite material according to any one of claims 1 to 3, characterized in that: The following steps are involved: The sulfur source and / or selenium source and the mineral matrix are subjected to mechanical ball milling to obtain the mineral-based composite material.

5. The preparation method according to claim 4, characterized in that The conditions of the mechanical ball milling include: a time of 1 to 6 hours and a rotation speed of 100 to 400 r / min; The ball milling aid is an ethanol aqueous solution and / or an acetic acid aqueous solution, and the liquid-solid ratio of the ball milling aid to the material is 0.1-0.5 mL: 0.5-1.5 g; The grinding balls are made of stainless steel or zirconium dioxide, with a particle size of 5 to 15 mm and a ball-to-material ratio of 5 to 20:

1.

6. The preparation method according to claim 4, characterized in that The method also includes calcining and acid leaching the mineral matrix in sequence.

7. The preparation method according to claim 6, characterized in that The calcination temperature is 450-600° C., and the calcination time is 1.5-4 hours.

8. The preparation method according to claim 6, characterized in that The reagent used for the acid leaching is one of hydrochloric acid and / or nitric acid.

9. Use of the mineral-based composite material according to any one of claims 1 to 3 or the mineral-based composite material prepared by the preparation method according to any one of claims 4 to 8 in gas-phase mercury removal.

10. The use according to claim 9, characterized in that The temperature in the gas phase demercuration is 90-150° C., the gas flow rate is 300-1000 mL / min, and the nitrogen content is 25-30 wt %.

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