Preparation method of high-temperature electrochemical biomass carbon anode

Abstract

The invention provides a preparation method of a high-temperature electrochemical biomass carbon anode, which belongs to the field of electrochemical metallurgy and comprises the following steps: step 1, performing crushing pretreatment on a biomass raw material in a room-temperature air environment; 2, in an argon atmosphere, putting the crushed biomass raw material obtained in the step 1 into a high-temperature heating furnace, and carrying out heating treatment to obtain a carbon black product; and 3, putting the carbon black product obtained in the step 2 into an SPS (spark plasma sintering) furnace, and sintering to obtain a compact carbon black block. The compact carbon black block can be used as a high-temperature electrochemical substance anode to carry out corresponding electrolysis or electrochemical test experiments. The method has the characteristics of low energy consumption, low pollution, high efficiency, simplicity in operation, wide applicability and the like. According to the method, the waste biomass can be sustainably utilized, carbon dioxide emission is reduced, the atmospheric pollution problem in the electrochemical experiment and production activity process is effectively solved, and the method can be applied to various systems for producing and refining various types of metals.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical metallurgy, and in particular relates to a method for preparing a high-temperature electrochemical biomass carbon anode. Background Art

[0002] The existing blast furnace ironmaking process has problems such as high fossil fuel consumption and large CO2 emissions. About 70% of the energy consumption and 80% of the CO2 emissions of the steel industry come from the ironmaking system. The pressure to reduce carbon emissions in the ironmaking process is huge. The various new ironmaking processes and technologies are still difficult to achieve zero-carbon production. The fundamental reason for the CO2 emission problem in the steel industry is that the process uses carbon as a reducing agent and energy source, which is difficult to solve the bottleneck problem of carbon emissions by itself. Other non-ferrous metal smelting processes also have a large amount of CO2 emissions.

[0003] In this context, it is particularly important to develop a carbon-neutral anode suitable for biomass conversion in high-temperature electrochemical metallurgy. In a broad sense, biomass includes all plants, microorganisms, animals that feed on plants and microorganisms, and their waste products. Representative biomass includes crops, crop waste, wood, wood waste, and animal manure. In a narrow sense, biomass mainly refers to materials such as straw, trees, and other wood cellulose in the agricultural and forestry production process, waste materials from the agricultural and forestry industry, and livestock and poultry manure and waste in the animal husbandry production process, except for grain and fruit. Such materials have the characteristics of low utilization rate and troublesome recycling. Therefore, this method can realize the recycling of a large amount of biomass materials without additional carbon emissions, effectively reducing air pollution. The surface area of ​​biomass materials is increased by crushing pretreatment, and the carbonization efficiency is increased; the carbon black material is shaped by SPS sintering technology for subsequent use; the prepared carbon black material is used as an electrochemical metallurgical anode for the preparation and purification of metal materials.

[0004] Based on this, the present invention provides a method for preparing a high-temperature electrochemical biomass carbon anode, which aims to reduce energy consumption in experiments and production processes, reduce carbon dioxide emissions, achieve green metallurgical goals, and effectively optimize air pollution problems during electrochemical experiments and production activities. Summary of the invention

[0005] The present invention provides a method for preparing a high-temperature electrochemical biomass carbon anode. Specifically, it can reduce energy consumption and carbon dioxide emissions in the process of high-temperature molten salt and molten oxide electrolysis, achieve the purpose of green metallurgy, and effectively optimize the atmospheric pollution problem in the process of electrochemical experiments and production activities. The present invention has the characteristics of low energy consumption, low pollution, high efficiency, simple operation and wide applicability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a high-temperature electrochemical biomass carbon anode comprises the following steps:

[0008] Step 1: In an air environment at room temperature, pre-crush the biomass raw materials to achieve a more ideal effect in the subsequent processing steps. The actual operation is: put an appropriate amount of experimental biomass raw materials into the crushing device, and process and crush the biomass raw materials in batches for several hours until their morphology is finely broken blocks or powder for use;

[0009] Step 2: Under an argon atmosphere, the crushed biomass raw material obtained in step 1 is placed in a high-temperature heating furnace for heating treatment, the purpose of which is to ensure that the biomass raw material is burned as fully as possible, improve the utilization efficiency, and obtain carbon black products under a certain temperature and time. This step does not require any additional additives, and only uses high temperature to modify the original biomass organic raw material into a hard carbon inorganic material;

[0010] Step 3: Place the carbon black product obtained in step 2 in an SPS spark plasma sintering furnace for sintering, the purpose of which is to form a dense carbon black block under a certain temperature, time and pressure. Through this step, the physical properties of the biomass material are strengthened, and its hardness and density are increased to the level of graphite material. The dense carbon black block obtained after sintering can be used as a high-temperature electrochemical biomass anode to carry out corresponding electrolysis or electrochemical test experiments.

[0011] Optionally, in step one, the biomass raw material is plant material mainly composed of carbon elements formed in natural processes such as straw, fallen leaves, and branches.

[0012] Optionally, in step 2, in order to ensure that different biomass materials are carbonized to obtain carbon black materials, the heating temperature is 500° C.-1600° C., and the heating time is 1 h-48 h.

[0013] Optionally, in step 2, the purity of the carbon black product is ≥99%.

[0014] Optionally, in step three, to ensure further molding of the carbon black material, the SPS spark plasma sintering temperature is 900° C.-1600° C., the sintering time is 5 min-60 min, and the sintering pressure is 5 MPa-50 MPa.

[0015] The present invention also provides a dense carbon black block prepared by the method, the density of which is ≥1g / cm 3 , tensile strength ≥90Mpa.

[0016] The present invention also provides an application of the dense carbon black block in the field of electrochemistry. Further, the dense carbon black block is used as a high-temperature electrochemical anode to carry out corresponding electrolysis or electrochemical test experiments. It can be applied to molten salt systems such as chloride systems and fluoride systems, and can also be applied to ultra-high temperature molten oxide systems. Its electrochemical reaction temperature is 300°C-1600°C, and it can be used for the extraction and refining of metal elements such as iron, aluminum, and titanium. It can withstand a current density of 0.01A / cm 2 -10A / cm 2 .

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1) Carbon black materials are abundant in raw materials, low in cost, and can be used in a wide range;

[0019] 2) The carbon black anode preparation process is simple to operate and has high repeatability;

[0020] 3) The carbon black anode preparation process has low energy consumption and can be prepared in large quantities. The electrode size can be designed according to actual application;

[0021] 4) The carbon black electrode is prepared to participate in electrolysis, which has a wide range of applicable systems, can reduce the production of CO2, achieve the purpose of green metallurgy, and effectively optimize the air pollution problem during electrochemical experiments and production activities. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of 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 creative work.

[0023] Figure 1 This is the SEM image of the carbon black product after sintering in step 2 of Example 1.

[0024] Figure 2 This is the SEM image of the dense carbon black block after SPS sintering in step three of Example 1.

[0025] Figure 3 The present invention is a flow chart of the method for preparing and using a biomass carbon anode based on high temperature electrochemistry.

[0026] Figure 4 The carbon black material obtained in Example 1 was used for electrolysis to obtain the XRD pattern of the product Fe. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] Step 1: After crushing 10 kg of straw raw materials, screen out straw particles less than 5 mm.

[0030] Step 2: Fill the screened raw materials evenly into a corundum crucible and place it in a vertical furnace. Keep it at 200°C in a vacuum environment for 10 h to remove moisture. Heat it to 750°C in an argon atmosphere at a heating rate of 5°C / min and keep it for 2 h. Figure 1 This is the SEM image of the carbon black product after sintering in step 2, which shows that the heating process converts the biomass material into carbon black material without adding any additives, and retains the structure of the biomass itself. The product is cooled to room temperature and taken out, and the carbonized block is ground into particles.

[0031] Step 3: Place 40g of ground particles in an SPS sintering mold. After the assembly is stable, place it in an SPS sintering furnace and set the temperature to 750°C, pressure to 10Mpa, and time to 20min to sinter the carbon black material. After SPS sintering, the density is 1.02g / cm 3 , amorphous carbon material with tensile strength of 90Mpa. Figure 2 This is the SEM image of the dense carbon black block after SPS sintering in step three.

[0032] Step 4: Use the obtained carbon black anode for electrolysis experiments. Prepare Fe2O3-CaF2 electrolyte in a mass ratio of 92:8 and place it in an alumina crucible. Keep the prepared electrolyte in a vacuum environment at 300°C for 4 hours to remove moisture, then heat it to 1400°C and melt it in an argon atmosphere. After the electrolyte is completely melted, place the molybdenum plate as the cathode at the bottom of the electrolytic cell; use the carbon black block as the anode for electrolysis. When the temperature in the electrolytic cell is uniform, apply 0.5A / cm 2 The constant current electrolysis was carried out for 2 h, and the cathode Fe product was collected after the electrolysis was completed. The product was pure phase crystals. Figure 4 The XRD diagram of the product reflects the product phase of pure crystalline iron after electrolysis. The electrolysis efficiency is 95%, reducing greenhouse gas emissions. The flow chart of the above-mentioned high temperature electrochemical biomass carbon anode preparation and use method is as follows Figure 3 shown.

[0033] Example 2

[0034] Step 1: After crushing 5 kg of maple leaf raw materials, select 5 mm maple leaf particles.

[0035] Step 2: Fill the screened raw materials evenly into a corundum crucible and place it in a vertical furnace. Keep it at 250°C in a vacuum environment for 8 hours to remove moisture. Heat it to 900°C in an argon atmosphere at a heating rate of 10°C / min and keep it for 4 hours. After the straw raw materials are completely carbonized, cool them to room temperature and take them out. Grind the carbonized blocks into particles.

[0036] Step 3: Place 50g of ground particles in an SPS sintering mold. After the assembly is stable, place it in an SPS sintering furnace, set the temperature to 900°C, the pressure to 15Mpa, and the time to 15min to sinter the carbon black material.

[0037] Step 4: Use the obtained carbon black anode for electrolysis experiments. Prepare TiO2-CaF2 electrolyte in a mass ratio of 80:20 and place it in an alumina crucible. Keep the prepared electrolyte in a vacuum environment at 200°C for 10 hours to remove moisture, then heat it to 1200°C and melt it in an argon atmosphere. After the electrolyte is completely melted, place the molybdenum plate as the cathode at the bottom of the electrolytic cell; use the carbon black block as the anode for electrolysis. When the temperature in the electrolytic cell is uniform, apply 0.25A / cm 2 The constant current electrolysis was carried out for 6 hours, and the cathode Ti product was collected after the electrolysis was completed. The electrolysis efficiency was 93%, reducing greenhouse gas emissions.

[0038] Example 3

[0039] Step 1: After crushing 10 kg of lignin raw material, 2 mm lignin particles are screened out.

[0040] Step 2: Fill the screened raw materials evenly into a corundum crucible and place it in a vertical furnace. Keep it at 300°C in a vacuum environment for 12 hours to remove moisture. Heat it to 800°C at a heating rate of 8°C / min in an argon atmosphere and keep it for 4 hours. After the straw raw materials are completely carbonized, cool them to room temperature and take them out. Grind the carbonized blocks into particles.

[0041] Step 3: Place 40g of ground particles in an SPS sintering mold. After the assembly is stable, place it in an SPS sintering furnace, set the temperature to 800°C, the pressure to 20Mpa, and the time to 10min to sinter the carbon black material.

[0042] Step 4: Use the obtained carbon black anode for electrolysis experiments. Prepare Fe2O3-CaF2 electrolyte in a mass ratio of 92:8 and place it in an alumina crucible. Keep the prepared electrolyte in a vacuum environment at 300°C for 6 hours to remove moisture, then heat it to 1500°C and melt it in an argon atmosphere. After the electrolyte is completely melted, place the molybdenum plate as the cathode at the bottom of the electrolytic cell; use the carbon black block as the anode for electrolysis. When the temperature in the electrolytic cell is uniform, apply 0.3A / cm2 The constant current electrolysis was carried out for 8 hours, and the cathode Al product was collected after the electrolysis was completed. The electrolysis efficiency was 90%, reducing greenhouse gas emissions.

[0043] Comparative Example 1

[0044] Only step 1 crushing and step 2 heating were performed, and step 3 SPS sintering was not performed, and the other steps were the same as in Example 1. The prepared carbon black material was in powder form, and it was not possible to complete the electrolysis experiment using it as a carbon black anode, and metal extraction and recovery could not be achieved.

[0045] Comparative Example 2

[0046] Only step 1 crushing and step 3 SPS sintering were performed, and step 2 heating was not performed, and the other steps were the same as Example 1. The prepared carbon black material was a block but the strength was too low, and it was impossible to complete the electrolysis experiment using it as a carbon black anode, and metal extraction and recovery could not be achieved.

[0047] Comparative Example 3

[0048] The preparation process includes steps 1 to 3. However, step 3 does not use SPS sintering, but is still heated in a vertical furnace, and the heating temperature and time are the same as in Example 1. The other steps are also the same as in Example 1. The prepared carbon black material is a block but has too low strength. It is impossible to complete the electrolysis experiment using it as a carbon black anode, and metal extraction and recovery cannot be achieved.

[0049] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a high temperature electrochemical biomass carbon anode, characterized in that: The following steps are involved: Step 1: Under room temperature air environment, the biomass raw materials are crushed and pre-treated; Step 2: placing the crushed biomass raw material obtained in step 1 in a high-temperature heating furnace under an argon atmosphere for heating to obtain a carbon black product; Step 3: Place the carbon black product obtained in step 2 in an SPS spark plasma sintering furnace and perform sintering treatment to obtain a dense carbon black block.

2. The method for preparing a high temperature electrochemical biomass carbon anode according to claim 1, characterized in that: In step 1, the biomass raw material is a plant material mainly composed of carbon elements formed in a natural process, and is selected from at least one of straw, fallen leaves, and branches.

3. The method for preparing a high temperature electrochemical biomass carbon anode according to claim 1, characterized in that: In step 2, the heating temperature is 500°C-1600°C, and the heating time is 1h-48h.

4. The method for preparing a high temperature electrochemical biomass carbon anode according to claim 1, characterized in that: In step three, the SPS spark plasma sintering temperature is 900° C.-1600° C., the sintering time is 5 min-60 min, and the sintering pressure is 5 MPa-50 MPa.

5. A dense carbon black block prepared by the method according to any one of claims 1 to 4.

6. The dense carbon black block according to claim 5, characterized in that Its density ≥1g / cm 3 , tensile strength ≥90Mpa.

7. Application of the dense carbon black block according to claim 5 in the field of electrochemistry.

8. The use according to claim 7, characterized in that: The dense carbon black block is used as a high-temperature electrochemical anode to carry out electrolysis or electrochemical testing experiments, and the electrochemical reaction temperature is 300°C-1600°C.

9. The use according to claim 8, characterized in that: The dense carbon black block is used for extraction and refining of metal elements.

10. The use according to claim 9, characterized in that: The metal element is selected from at least one of iron, aluminum and titanium.

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