Method for high-value utilization of micro-fine mineral powder solid waste

Abstract

The application discloses a kind of micro-mineral powder solid waste high-value utilization method, comprising the following steps: after micro-mineral powder natural air drying, grinding sieving, obtain micro-mineral powder raw material;Micro-mineral powder is mixed with different proportions of biomass uniformly, placed in muffle furnace high-temperature oxygen-limited pyrolysis, then after modification of phosphoric acid, citric acid, CaCl2 etc., obtain micro-mineral powder / biomass nanocomposite;Micro-mineral powder / biomass nanocomposite is dispersed in water with chitosan, and ultrasonic composite for a period of time to obtain chitosan / micro-mineral powder / biomass nanocomposite mixed liquor;The above-mentioned mixed liquor drop is coated on the surface of glassy carbon electrode, and a chemically modified electrode is prepared;The above-mentioned electrode is used for the detection of dopamine, nitrite substance.The application can prepare high electrocatalytic activity micro-mineral powder nanomaterial, which can be used as electrode material for battery, electrochemical sensor, capacitor and other fields.

Description

Technical Field

[0001] This invention relates to the field of solid waste technology, and more specifically to a method for the high-value utilization of micro-mineral powder solid waste. Background Technology

[0002] Micro-mineral powder is produced by wet pulverizing carbonaceous material sources to micron-sized particles before combustion / conversion using micro-mineral separation technology. Following particle surface modification and multiphase flow interface control, trace elements and minerals are separated from the carbonaceous material sources, resulting in the extraction of clean solid fuel from low-quality coal, leaving behind solid waste. A large amount of micro-mineral powder is generated during the refining of low-quality coal using micro-mineral separation technology, and this powder is typically stored in tailings ponds.

[0003] Currently, the utilization of micro-mineral powder is mainly focused on concrete improvement. Micro-mineral powder is a solid waste emitted after refining clean solid fuel from low-quality coal. Its chemical composition is mainly composed of oxides of iron, silicon, aluminum, and calcium, making it an important secondary solid resource. Directly using it in concrete building materials cannot maximize its effective role. This invention prepares electrocatalytic materials for electrodes and capacitors by modifying micro-mineral powder through high-temperature oxygen-limited pyrolysis carbonization with different biomass, providing a way to achieve high-value utilization of micro-mineral powder. Summary of the Invention

[0004] In view of this, in order to solve or partially solve the problems existing in the related technologies for the high-value utilization of micro mineral powder, the present invention provides a method for the high-value utilization of micro mineral powder solid waste; it can prepare micro mineral powder nanomaterials with high electrocatalytic activity, which can be used as electrode materials in batteries, electrochemical sensors, capacitors and other fields.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for high-value utilization of micro-mineral powder solid waste includes the following steps:

[0007] (1) After the micro mineral powder is naturally air-dried, it is ground and sieved to obtain micro mineral powder raw material;

[0008] (2) Mix micro-mineral powder with biomass of different proportions evenly, place it in a muffle furnace for high-temperature oxygen-limited pyrolysis, and then modify it with phosphoric acid and citric acid or directly with CaCl2 to obtain micro-mineral powder / biomass nanocomposite material.

[0009] (3) Disperse the micro-mineral powder / biomass nanocomposite material and chitosan in water, and ultrasonically combine them for a period of time to obtain a chitosan / micro-mineral powder / biomass nanocomposite material mixture;

[0010] (4) The above mixture is drop-coated onto the surface of a glassy carbon electrode to prepare a chemically modified electrode;

[0011] (5) The above electrodes were used for the detection of dopamine and nitrite.

[0012] Preferably, the sieving in step (1) is sieve 40 mesh.

[0013] Preferably, the biomass includes one or more of the following: ginger stalks, tomato stalks, eggplant stalks, broccoli stalks, enoki mushroom stalks, walnut branches, and walnut shells.

[0014] Preferably, the mass ratio of the micro-mineral powder to biomass is 10:1 to 1:10.

[0015] Preferably, the high-temperature oxygen-limited pyrolysis is performed at 500-1000℃ for 1-5 hours.

[0016] Preferably, the phosphoric acid modification is as follows: weigh a certain amount of micro mineral powder, add 42% phosphoric acid (concentrated phosphoric acid and water are mixed in a 1:1 ratio), stir, soak at room temperature for 12 hours, filter and dry, put it in a muffle furnace and pyrolyze at 600℃ for 3 hours, grind it into powder, pass it through a 100-mesh sieve, and it is phosphoric acid modified micro mineral powder biochar.

[0017] Citric acid modification is as follows: Take phosphoric acid modified micromineral biochar, add citric acid, stir for a certain time and then filter, dry at 60℃ for 24h, gradually increase the temperature to 120℃ and keep it for 2h, grind into powder, pass through a 100-mesh sieve, which is phosphoric acid and citric acid modified micromineral biochar.

[0018] The CaCl2 modification is as follows: Micromineral biochar and 0.05-0.5 mol / L calcium chloride solution are placed in a constant temperature shaker at a solid-liquid ratio of 1 g: 15 mL and shaken for 24 h. After filtration, the mixture is washed with deionized water until the conductivity is stable. Then, it is dried in an oven at 105 ℃ for 5 h and finally subjected to oxygen-limited pyrolysis at 200 ℃ for 1 h. The mixture is then ground into powder in a mortar and passed through a 100-mesh sieve to obtain the calcium chloride-modified micromineral biochar.

[0019] Preferably, the mass ratio of the micromineral powder / biomass nanocomposite material to chitosan is 3:1 to 1:3.

[0020] Preferably, the ultrasonic composite time is 1-4 hours.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention uses micro-mineral powder as raw material to prepare electrocatalytic materials, which reduces the damage to the ecological environment caused by the accumulation of micro-mineral powder and realizes the reduction and high-value utilization of solid waste.

[0023] 2. The process of this invention is simple and easy to implement, and the modified electrocatalytic effect is significant, enabling rapid detection of low concentrations of electroactive substances such as nitrite and dopamine.

[0024] 3. The present invention introduces chitosan, which can not only improve the stability of the electrode, but also improve its electrocatalytic activity.

[0025] 4. The raw materials used in this method are readily available, the cost is low, the operation is simple, and the added value is high. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 Current-time for different concentrations of dopamine.

[0028] Figure 2 Cyclic voltammetry curves of electrodes modified with different materials against 0.3 mM sodium nitrite;

[0029] Figure 3 Differential pulse voltammetry curves (A) of the electrode modified with micromineral powder / ginger stalk biochar sodium composite material to different concentrations of sodium nitrite;

[0030] Figure 4 Electrochemical response curves (A) and linear graphs (B) of different concentrations of dopamine on the surface of electrodes modified with phosphoric acid + citric acid micromineral powder nanomaterials;

[0031] Figure 5 Electrochemical response of different concentrations of dopamine on the surface of an electrode modified with phosphoric acid and citric acid-modified micromineral powder nanocomposite material.

[0032] Figure 6 Electrochemical response of different concentrations of dopamine on the surface of CaCl2-modified micromineral powder nanocomposite modified electrode. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] The micro-mineral powder material was crushed into small pieces using a crusher or hammer, passed through a 40-mesh sieve, and then placed in a sealed crucible with a lid. The crucible was placed in a muffle furnace at 700℃ and subjected to oxygen-limited pyrolysis for 3 hours. After grinding, the material was passed through a 100-mesh sieve to obtain the micro-mineral powder nanomaterial. 5-20 mg of the above micro-mineral powder nanomaterial was weighed, added to 5 ml of ultrapure water, and ultrasonically vibrated for 1 hour. 5-10 μL of the dispersion was then pipette-coated onto a clean electrode surface to obtain an electrode surface containing the modified material. This surface was then dried under an incandescent lamp for later use.

[0036] The micro-mineral powder-modified electrode exhibits good electrocatalytic activity for dopamine within a working potential range of 0.30 V. With increasing dopamine concentration, the electrode shows a significantly enhanced response current signal, and the response speed is very fast; the response time to reach 90% of the steady-state current is less than 5 s. Linear fitting was performed on two concentration ranges: y1 = 0.10797x + 0.0782, with a correlation coefficient R² = 0.9719; y2 = 0.00549x + 0.2436, with a correlation coefficient R² = 0.9875, and a response sensitivity of 0.10797 μA / (μmol / L).

[0037] Example 2

[0038] The pulverized ginger stalk powder and micromineral powder were mixed evenly in ratios of 1:0, 0:1, 1:1, 1:2, 2:1, 1:3, 3:1, 2:3, and 3:2, respectively. The mixtures were then subjected to oxygen-limited pyrolysis at 700℃ for 3 hours. The resulting mixtures were ground and passed through a 100-mesh sieve to prepare ginger stalk / micromineral powder biochar nanocomposites. 5-20 mg of each of the nine micromineral powder nanomaterials were weighed and added to 3 mL of ultrapure water. The mixtures were ultrasonically dispersed for 1 hour to obtain suspensions containing the modified materials. 5-10 μL of the dispersion was pipetted onto a clean electrode surface and dried under an infrared lamp for later use.

[0039] Figure 2 The effect of the mass ratio of ginger stalks to micro-mineral powder on the electrochemical performance of micro-mineral powder / ginger stalk biochar nanocomposites. Figure 2 It can be seen that when the ratio of ginger stem to micro-mineral powder is 2:3, the prepared nanocomposite material has the smallest oxidation peak potential value and the highest oxidation peak current for sodium nitrite, which is more conducive to the detection of sodium nitrite.

[0040] Compared to bare electrodes, pure micromineral powder, pure ginger stalks, and micromineral powder / ginger stalk biochar materials can all enhance the detection performance of sodium nitrite, with the micromineral powder / ginger stalk biochar nanocomposite material showing the best effect. Figure 3 As shown.

[0041] The current response of different concentrations of nitrite on the electrode surface was determined using differential pulse voltammetry. Figure 4 As shown in Figure A. Figure 4 As shown in B, the linear range is relatively wide, with a good linear relationship between sodium nitrite concentration (5 μM to 1000 μM) and peak current. The linear correlation coefficient R² is 0.9980, and the linear equation is ipa = 0.00566χ + 0.11565. The detection limit for sodium nitrite is low, reaching 2 μM.

[0042] Example 3

[0043] Micromineral powder is crushed into small pieces using a crusher or hammer, passed through a 40-mesh sieve, and then placed in a sealed crucible with a lid. The crucible is placed in a muffle furnace at 600℃ for oxygen-limited pyrolysis for 3 hours. After grinding, it is passed through a 100-mesh sieve to obtain micromineral powder nanomaterials. 100g of micromineral powder is weighed and 100mL of 42% phosphoric acid (concentrated phosphoric acid and water mixed in a 1:1 ratio) is added. The mixture is stirred with a rotor and soaked at room temperature for 12 hours. After filtration and drying, it is placed in a crucible, compacted, and then pyrolyzed in a muffle furnace at 600℃ for 3 hours. After cooling, it is ground into powder in a mortar and passed through a 100-mesh sieve. The material passing through the sieve is phosphoric acid-modified micromineral powder biochar. 10g of phosphoric acid-modified micromineral powder biochar is taken and 200mL of 1mol / L citric acid is added. The mixture is stirred for 2 hours and then filtered. It is then dried in a drying oven at 60℃ for 24 hours, gradually increasing the temperature to 120℃ and maintaining this temperature for 2 hours. After cooling, grind the material into powder in a mortar and pass it through a 100-mesh sieve. The material that passes through the sieve is phosphoric acid and citric acid modified micromineral biochar.

[0044] Weigh 5-20 mg of different micro-mineral powder nanomaterials, mix and grind them with chitosan, then add 5-20 ml of ultrapure water and sonicate for 1 h to obtain a suspension containing different micro-mineral powder nanomaterials. Use a pipette to take 5-10 μL of the dispersion and drop it onto a clean electrode surface, then dry it under an infrared lamp for later use.

[0045] The current response of 0.1, 0.5, 1, 5, 10, 50, and 100 μM dopamine on the surface of an electrode modified with phosphoric acid and citric acid-modified micromineral powder nanomaterials was determined by cyclic voltammetry. Figure 5 As shown.

[0046] Example 4

[0047] The micro-mineral powder material was crushed into small pieces using a crusher or hammer, passed through a 40-mesh sieve, and then placed in a sealed crucible with a lid. The crucible was placed in a muffle furnace at 600℃ for oxygen-limited pyrolysis for 3 hours. After grinding, the material was passed through a 100-mesh sieve to obtain micro-mineral powder nanomaterials. The micro-mineral powder nanomaterials and a 0.05-0.5 mol / L calcium chloride solution were mixed at a solid-liquid ratio of 1 g:15 mL in a constant-temperature shaker for 24 hours, then filtered. The mixture was washed with deionized water until the conductivity stabilized, then dried in an oven at 105℃ for 5 hours, and finally subjected to oxygen-limited pyrolysis at 200℃ for 1 hour. The resulting powder was ground in a mortar and passed through a 100-mesh sieve to obtain the prepared calcium chloride-modified micro-mineral powder biochar. Weigh 5-20 mg of CaCl2-modified micro-mineral powder nanocomposite material, mix and grind it with chitosan, then add 5-20 ml of ultrapure water, and ultrasonically disperse for 1 h to obtain a suspension of CaCl2-modified micro-mineral powder nanocomposite material. Use a pipette to take 5-10 μL of the dispersion and drop it onto a clean electrode surface, then dry it under an infrared lamp for later use.

[0048] The current response of 0.1, 0.5, 1, 5, 10, and 100 μM dopamine on the surface of an electrode modified with CaCl2-modified micromineral powder nanocomposite material was determined by cyclic voltammetry. Figure 6 As shown.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for high-value utilization of micro-mineral powder solid waste, characterized in that, Includes the following steps: (1) After the micro mineral powder is naturally air-dried, it is ground and sieved to obtain micro mineral powder raw material; (2) Mix micro mineral powder with biomass of different proportions evenly, place it in a muffle furnace and pyrolyze it at 500-1000℃ for 1-5 hours under high temperature and limited oxygen. Then, modify it with phosphoric acid and citric acid or directly modify it with CaCl2 to obtain micro mineral powder / biomass nanocomposite material. (3) Disperse the micro-mineral powder / biomass nanocomposite material and chitosan in water, and ultrasonically combine them for a period of time to obtain a chitosan / micro-mineral powder / biomass nanocomposite material mixture; (4) The above mixture is drop-coated onto the surface of a glassy carbon electrode to prepare a chemically modified electrode; (5) The above electrodes were used for the detection of dopamine and nitrite.

2. The method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, The sieving mentioned in step (1) is sieving through a 40-mesh sieve.

3. The method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, The biomass includes one or more of the following: ginger stalks, tomato stalks, eggplant stalks, broccoli stalks, enoki mushroom stalks, walnut branches, and walnut shells.

4. The method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, The mass ratio of the micro-mineral powder to biomass is 10:1 to 1:

10.

5. The method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, Phosphoric acid modification is as follows: Weigh a certain amount of micro-mineral biochar, add 42% phosphoric acid, stir, soak at room temperature for 12 h, filter and dry, then put it into a muffle furnace and pyrolyze at 600℃ for 3 h, grind it into powder, and pass it through a 100-mesh sieve to obtain phosphoric acid modified micro-mineral biochar. Citric acid modification is as follows: Take phosphoric acid-modified micromineral biochar, add citric acid, stir for a certain time, filter, dry at 60℃ for 24 h, gradually increase the temperature to 120℃, maintain for 2 h, grind into powder, and pass through a 100-mesh sieve, which is phosphoric acid and citric acid modified micromineral biochar. The CaCl2 modification is as follows: Micromineral biochar and 0.05-0.5 mol / L calcium chloride solution are placed in a constant temperature shaker at a solid-liquid ratio of 1 g:15 mL and shaken for 24 h. After filtration, the mixture is washed with deionized water until the conductivity is stable. Then, it is dried in an oven at 105℃ for 5 h and finally subjected to oxygen-limited pyrolysis at 200℃ for 1 h. The mixture is then ground into powder in a mortar and passed through a 100-mesh sieve to obtain the calcium chloride-modified micromineral biochar.

6. The method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, The mass ratio of the micromineral powder / biomass nanocomposite material to chitosan is 3:1-1:

3.

7. A method for high-value utilization of micro-mineral powder solid waste according to claim 1, characterized in that, The duration of the ultrasonic composite is 1-4 hours.

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