A method of chemically fixing carbon dioxide with liquid metal

Abstract

The present application relates to a kind of liquid metal carbon dioxide chemical solidification method, the method includes the following steps: (1) the gas containing carbon dioxide is introduced into liquid metal and is reacted, and solid-liquid separation is carried out to obtain liquid metal and solid mixture;(2) the solid mixture obtained in step (1) is treated by alkali, and carbon element and metal salt solution are obtained;The metal salt solution obtained is treated by electrolysis, and solid metal and oxygen are obtained;The liquid metal includes active component, and the active component includes any one or the combination of at least two of Ga, Al, Sn or Zn.The present application uses low-melting metal component capable of producing amphoteric oxide and having specific electronic structure, reduces carbon dioxide in liquid form, and recovers metal component through reduction process, and the reaction efficiency of carbon dioxide is higher, with the characteristics of mild reaction condition and low cost.

Description

Technical Field

[0001] This invention relates to the field of chemical carbon fixation technology, and more specifically to a method for chemically solidifying carbon dioxide using liquid metal. Background Technology

[0002] In recent years, the extensive use of fossil fuels has caused severe environmental pollution and emitted large amounts of carbon dioxide. To address the global climate change crisis caused by the increasing carbon emissions, the conversion of carbon dioxide has become a current research hotspot, and carbon capture, utilization, and storage (CVC) has become one of the key technologies for addressing global climate change.

[0003] The most common target product of carbon dioxide conversion is carbon monoxide, which contains one carbon atom. Other products include methanol, formic acid, and some ethanol. CN 104477910A discloses a method for preparing carbon monoxide by photothermal chemical cyclic decomposition of carbon dioxide, including the following steps: mixing zinc nitrate, deionized water, glacial acetic acid, and anhydrous ethanol to prepare solution A; adding tetrabutyl titanate to anhydrous ethanol to prepare solution B; pouring solution A into solution B and stirring until gel is formed; drying the colloid and grinding it into a fine powder; heating and calcining it to obtain a binary composite metal oxide; then irradiating the reaction with a light source; and finally introducing CO2 and heating the reaction to produce CO.

[0004] CN 114105723A discloses a method for converting carbon dioxide into methane via metal hydrides, comprising the following steps: Step 1, hydrogenating Mg powder with H2 at 300-600℃ to obtain MgH2 hydrogen storage material; first, ball milling Mg powder with a transition metal, then hydrogenating the resulting mixture with H2 at 300-600℃ to obtain a composite magnesium-based hydrogen storage material; Step 2, reacting a molecular sieve adsorbed with CO2 with the MgH2 hydrogen storage material or the composite magnesium-based hydrogen storage material under the protection of an inert gas at 250-600℃ to obtain a mixed gas; Step 3, separating the methane from the mixed gas to obtain methane.

[0005] The core of the research on the above inventions lies in the conversion and utilization of carbon dioxide. However, given the current level of carbon dioxide emissions, the products obtained from these carbon dioxide treatment technologies, which can reduce emissions, may render them uneconomical. Therefore, some scholars believe that the focus of technology development should be on capture-storage, especially storage technologies, which require greater technological investment.

[0006] Chemical solidification of carbon dioxide is one of the important technical approaches for carbon dioxide treatment. For example, alkaline oxides such as calcium oxide are used to convert carbon dioxide into carbonates. CN 114262631A discloses a novel method and apparatus for producing hydrogen from solid oxides and water. Coal and / or biomass and / or waste are uniformly mixed with oxides to form reactants. Supercritical water / high-temperature steam / high-pressure steam reacts with the reactants to produce hydrogen and carbon dioxide. Simultaneously, carbon dioxide undergoes a carbonation reaction with the oxides. The heat released by the carbonation reaction provides the heat absorbed by the gasification reaction, thus solidifying carbon dioxide into harmless calcium carbonate and reducing or eliminating carbon dioxide emissions. However, the recycling of alkali generally requires high temperatures above 900-1000℃ to recover and reuse calcium oxide. Even with the addition of other metal oxides for improvement, high temperatures of 750-850℃ are often required for recovery, significantly increasing energy consumption.

[0007] In addition, for the special application scenario of removing carbon dioxide in enclosed spaces, methods such as adsorption with strong alkaline substances, introduction of lithium hydroxide carbon dioxide removal agent, superoxide carbon dioxide removal technology, or physical temperature and pressure swing adsorption are usually used. However, these methods may have drawbacks such as large reagent consumption, high cost, and complex processes.

[0008] Therefore, in view of the shortcomings of existing technologies, there is an urgent need to provide a method for chemically curing carbon dioxide that is low in cost and highly efficient in carbon dioxide reaction. Summary of the Invention

[0009] The purpose of this invention is to provide a method for chemically curing carbon dioxide with liquid metal. The method uses liquid metal to reduce carbon dioxide. The liquid metal is a low-melting-point metal component that can produce amphoteric oxides and has a specific electronic structure. This allows carbon in carbon dioxide to efficiently produce metal-carbon intermediates with the metal, which further polymerizes the carbon chain to form solid carbon. This method is characterized by high efficiency, simplicity, and low cost.

[0010] To achieve this objective, the present invention employs the following technical solution:

[0011] This invention provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0012] (1) A gas containing carbon dioxide is passed into liquid metal to react, and a mixture of liquid metal and solid is obtained by solid-liquid separation;

[0013] (2) The solid mixture obtained in step (1) is treated with alkali to obtain carbon element and metal salt solution; the obtained metal salt solution is electrolyzed to obtain solid metal and oxygen.

[0014] The liquid metal includes an active component, which includes any one or a combination of at least two of Ga, Al, Sn, or Zn. Typical but non-limiting combinations include combinations of Ga and Sn, Sn and Zn, Ga, Sn, and Zn, or Ga, Al, Sn, and Zn.

[0015] The active components can be selected from a variety of different options. Ga makes the melting point of the solution system close to or below room temperature, which is convenient for operation under mild conditions. The high-entropy alloy system formed by the combination of multiple alloy components can improve the solid carbon ratio, thereby improving the reaction efficiency. By selecting low-cost materials such as Sn and Zn as the main components, the operating temperature can be appropriately increased to achieve lower costs.

[0016] The method provided by this invention involves directly introducing a gas containing carbon dioxide into a liquid metal, creating gas-liquid contact. The reaction immediately produces solid carbon, and during the reaction, the carbon dioxide oxidizes some of the metal components. The reaction equation for this process is as follows:

[0017] CO2 (gas) + M (liquid) → C (solid) + MO2 (solid) (1)

[0018] Where M represents a metallic element. The resulting solid carbon and metal oxides, due to their lower density, float on the surface of the liquid metal. When the solid mixture is treated with an alkaline solution, the metal oxides react with the alkali to form a metal salt solution, while the carbon remains as a solid. Electrolysis of the metal salt solution recovers the solid metal and generates oxygen. The reaction process is as follows:

[0019] MO2+2OH - →MO3 2- +H2O (2)

[0020] MO3 2- +H₂O→M↓+2OH⁻ - +O2↑ (3)

[0021] Reactions (2) and (3) are carried out in a metal salt solution. The produced metal is deposited and recovered on the electrode, and oxygen is released as the only gaseous product. The chemical-electrochemical addition reaction in the metal salt solution is as follows:

[0022] MO2→M+O2↑ (4)

[0023] First, reaction (1) is carried out, then the metal is recovered through reaction (4). The two reactions are summed, and the overall reaction is:

[0024] CO2→C(solid)+O2↑(5)

[0025] The method provided by this invention operates at a relatively mild temperature, and the energy required is only the internal energy of maintaining the liquid metal in a liquid state and the electrical energy consumed in electrolyzing the metal salt solution. The resulting reaction is that carbon dioxide is converted into solid carbon and oxygen is released.

[0026] Preferably, the liquid metal in step (1) includes an auxiliary component, which includes any one or a combination of at least two of In, Bi, Cd, Cu, Ni, Hg, Pb, Cr or Ce. Typical but non-limiting combinations include combinations of In, Bi, Cd and Cu, combinations of In and Bi, combinations of Cd, Cu, Ni and Hg, or combinations of In, Bi, Cd, Cu, Ni, Hg, Pb, Cr and Ce.

[0027] Preferably, the liquid metal in step (1) is obtained by melting or wet reduction of solid metal.

[0028] Preferably, the concentration of carbon dioxide in the gas containing carbon dioxide in step (1) is 0.001-100%, for example, it can be 0.001%, 0.1%, 10%, 50% or 100%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the temperature during the introduction in step (1) is 20-400℃, for example, it can be 20℃, 100℃, 200℃, 300℃ or 400℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Metals with different melting points are selected based on the temperature at which the carbon dioxide is introduced, ensuring that the metal contacts the carbon dioxide in a liquid state.

[0031] Preferably, the reaction in step (1) is carried out in a gas-liquid reaction apparatus.

[0032] Preferably, the gas-liquid reaction device is provided with an air inlet at the top.

[0033] Preferably, the air inlet is used to introduce gas containing carbon dioxide.

[0034] Preferably, the solid mixture in step (1) is a mixture of carbon element and metal oxide.

[0035] Preferably, the concentration of the alkaline solution used in the alkaline treatment in step (2) is 0.1-10 mol / L, for example, it can be 0.1 mol / L, 0.5 mol / L, 1 mol / L, 5 mol / L or 10 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the alkaline solution comprises sodium hydroxide solution and / or potassium hydroxide solution.

[0037] Preferably, the carbon element in step (2) is obtained by washing after alkali treatment.

[0038] Preferably, the solid metal in step (2) is deposited on the electrode.

[0039] As a preferred embodiment of the method described in this invention, the method includes the following steps:

[0040] (1) A gas containing 0.001-100% carbon dioxide is introduced into a gas-liquid reaction device at 20-400℃ through the gas inlet to react with liquid metal, and the liquid metal and solid mixture are obtained by solid-liquid separation.

[0041] The liquid metal includes an active component, which includes any one or a combination of at least two of Ga, Al, Sn, or Zn; the liquid metal includes an auxiliary component, which includes any one or a combination of at least two of In, Bi, Cd, Cu, Ni, Hg, Pb, Cr, or Ce; the liquid metal is obtained from a solid metal by smelting or wet reduction.

[0042] (2) The solid mixture obtained in step (1) is treated with sodium hydroxide solution and / or potassium hydroxide solution with a concentration of 0.1-10 mol / L to obtain carbon element and metal salt solution; the obtained metal salt solution is electrolyzed to obtain solid metal and oxygen deposited on the electrode.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The method for liquid metal chemical solidification of carbon dioxide provided by the present invention uses a low-melting-point metal component that can generate amphoteric oxides and has a specific electronic structure to reduce carbon dioxide in liquid form, and recovers the metal component through the reduction process. The reaction efficiency of carbon dioxide can reach 1.89 mmol / h, and it has the characteristics of mild conditions, high reaction efficiency and low cost. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0046] Example 1

[0047] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0048] (1) Argon gas as the balance gas and carbon dioxide concentration of 50% are introduced into the gas-liquid reaction device at 200°C through the gas inlet to react with liquid In-Sn alloy. After cooling, solid-liquid separation is performed to obtain liquid In-Sn alloy and a mixture of carbon element and indium tin oxide. The liquid In-Sn alloy is obtained by melting In particles and Sn particles with a mass ratio of 1:1 at 250°C.

[0049] (2) The mixture of carbon and indium tin oxide obtained in step (1) is treated with an alkaline solution of sodium hydroxide with a concentration of 1 mol / L to obtain carbon and sodium indium stannate; the carbon is cleaned and the sodium indium stannate is electrolyzed to obtain a solid In-Sn alloy and oxygen deposited on the electrode.

[0050] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 1.34 mmol / h.

[0051] Example 2

[0052] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal. The difference from Embodiment 1 is that, except for adjusting the carbon dioxide concentration in the gas described in step (1) to 0.001%, the rest is the same as in Embodiment 1.

[0053] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 0.06 mmol / h.

[0054] Example 3

[0055] This embodiment provides a method for chemically curing carbon dioxide with liquid metal. The difference from Embodiment 1 is that the gas in step (1) is adjusted to a 100% concentration of carbon dioxide, while the rest is the same as in Embodiment 1.

[0056] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 1.89 mmol / h.

[0057] Example 4

[0058] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0059] (1) Argon gas as the balance gas and carbon dioxide concentration of 50% are introduced into a gas-liquid reaction device at 200°C through the gas inlet to react with liquid Ga-In-Sn alloy. After cooling, solid-liquid separation is performed to obtain liquid Ga-In-Sn alloy and a mixture of carbon element and gallium indium tin oxide. The liquid Ga-In-Sn alloy is obtained by melting Ga particles, In particles and Sn particles in a mass ratio of 8:1:1 at 250°C.

[0060] (2) The mixture of carbon element and gallium indium tin oxide obtained in step (1) is treated with sodium hydroxide solution with a concentration of 1 mol / L to obtain carbon element and gallium indium tin sodium salt solution; the obtained carbon element is cleaned and the obtained gallium indium tin sodium salt solution is electrolyzed to obtain solid Ga-In-Sn alloy and oxygen deposited on the electrode.

[0061] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 0.91 mmol / h.

[0062] Example 5

[0063] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0064] (1) Argon gas as the balance gas and carbon dioxide concentration of 50% are introduced into the gas-liquid reaction device at 400°C through the gas inlet to react with liquid Ga-Sn-Zn-Bi alloy. After cooling, solid-liquid separation is performed to obtain liquid Ga-Sn-Zn-Bi alloy and a mixture of carbon element and Ga-Sn-Zn-Bi oxide. The liquid Ga-Sn-Zn-Bi alloy is obtained by melting Ga particles, Sn particles, Zn particles and Bi particles in a mass ratio of 7:1:1:1 at 450°C for 30 min and removing surface oxides.

[0065] (2) The mixture of carbon elemental and Ga-Sn-Zn-Bi system oxide obtained in step (1) is treated with alkali solution of potassium hydroxide with a concentration of 0.1 mol / L to obtain carbon elemental and Ga-Sn-Zn-Bi system potassium salt solution; the obtained carbon elemental is cleaned, and the obtained Ga-Sn-Zn-Bi system potassium salt solution is electrolyzed to obtain solid Ga-Sn-Zn-Bi alloy and oxygen deposited on the electrode.

[0066] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 1.26 mmol / h.

[0067] Example 6

[0068] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0069] (1) Argon gas as the balance gas and carbon dioxide concentration of 50% are introduced into the gas-liquid reaction device at 400°C through the gas inlet to react with liquid Sn-Zn alloy. After cooling, solid-liquid separation is performed to obtain liquid Sn-Zn alloy and a mixture of carbon element and zinc tin oxide. The liquid Sn-Zn alloy is obtained by melting Sn particles and Zn particles with a mass ratio of 9:1 at 450°C for 30 min and removing surface oxides.

[0070] (2) The mixture of carbon and zinc tin oxide obtained in step (1) is treated with sodium hydroxide solution with a concentration of 0.1 mol / L to obtain carbon and sodium zinc stannate; the obtained carbon is cleaned and the obtained sodium zinc stannate is electrolyzed to obtain solid Sn-Zn alloy and oxygen deposited on the electrode.

[0071] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 0.95 mmol / h.

[0072] Example 7

[0073] This embodiment provides a method for chemically solidifying carbon dioxide with liquid metal, the method comprising the following steps:

[0074] (1) Argon gas as the balance gas and carbon dioxide concentration of 50% are introduced into the gas-liquid reaction device through the gas inlet at 400°C to react with liquid Sn-Bi-Pb alloy. After cooling, solid-liquid separation is performed to obtain liquid Sn-Bi-Pb alloy and a mixture of carbon element and tin-bismuth-lead oxide. The liquid Sn-Bi-Pb alloy is obtained by melting Sn particles, Bi particles and Pb particles in a mass ratio of 8:1:1 at 450°C for 30 min and removing surface oxides.

[0075] (2) The mixture of carbon element and tin bismuth lead oxide obtained in step (1) is treated with sodium hydroxide solution with a concentration of 0.1 mol / L to obtain carbon element and tin bismuth lead sodium salt solution; the obtained carbon element is cleaned and the obtained tin bismuth lead sodium salt solution is electrolyzed to obtain solid Sn-Bi-Pb alloy and oxygen deposited on the electrode.

[0076] Based on the mass of the obtained carbon element, the reaction efficiency of carbon dioxide was calculated to be 0.87 mmol / h.

[0077] Comparative Example 1

[0078] This comparative example provides a method for chemically curing carbon dioxide with liquid metal. The difference from Example 1 is that the liquid In-Sn alloy in step (1) is replaced with a liquid Bi-In alloy. The liquid Bi-In alloy is obtained by melting Bi particles and In particles with a mass ratio of 3:5 at 350°C. All other aspects are the same as in Example 1.

[0079] Because the liquid Bi-In alloy lacks catalytically active metal components, it does not have the ability to reduce carbon dioxide.

[0080] In summary, the liquid metal chemical solidification method for carbon dioxide provided by this invention uses a low-melting-point metal component that can generate amphoteric oxides and has a specific electronic structure to reduce carbon dioxide in liquid form, and recovers the metal component through the reduction process. The reaction efficiency of carbon dioxide can reach 1.89 mmol / h, and it has the characteristics of mild conditions, high reaction efficiency and low cost.

[0081] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for chemically solidifying carbon dioxide with liquid metal, characterized in that, The method includes the following steps: (1) Gas containing carbon dioxide is directly introduced into liquid metal to produce gas-liquid contact. Solid carbon is immediately produced in the reaction. During the reaction, carbon dioxide will oxidize some metal components. After solid-liquid separation, a mixture of liquid metal and solid is obtained. The solid mixture is a mixture of carbon element and metal oxide. (2) The solid mixture obtained in step (1) is treated with alkali to obtain carbon element and metal salt solution; the obtained metal salt solution is electrolyzed to obtain solid metal and oxygen. The liquid metal includes an active component, which includes any one or a combination of at least two of Ga, Al, Sn, or Zn.

2. The method according to claim 1, characterized in that, The liquid metal in step (1) includes auxiliary components, which include any one or a combination of at least two of In, Bi, Cd, Cu, Ni, Hg, Pb, Cr or Ce.

3. The method according to claim 1, characterized in that, The liquid metal in step (1) is obtained by melting or wet reduction of solid metal.

4. The method according to claim 1, characterized in that, The concentration of carbon dioxide in the gas containing carbon dioxide in step (1) is 0.001-100%.

5. The method according to claim 1, characterized in that, The temperature during the introduction in step (1) is 20-400℃.

6. The method according to claim 1, characterized in that, The reaction described in step (1) is carried out in a gas-liquid reaction apparatus.

7. The method according to claim 6, characterized in that, The gas-liquid reaction device is provided with an air inlet at the top.

8. The method according to claim 1, characterized in that, The concentration of the alkaline solution used in step (2) is 0.1-10 mol / L.

9. The method according to claim 8, characterized in that, The alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution.

10. The method according to claim 1, characterized in that, The carbon element described in step (2) is obtained by washing after alkali treatment.

11. The method according to claim 1, characterized in that, The solid metal in step (2) is deposited on the electrode.

12. The method according to any one of claims 1-11, characterized in that, The method includes the following steps: (1) A gas containing 0.001-100% carbon dioxide is introduced into a gas-liquid reaction device at 20-400℃ through the gas inlet to react with liquid metal, and the liquid metal and solid mixture are obtained by solid-liquid separation; The liquid metal includes an active component, which includes any one or a combination of at least two of Ga, Al, Sn, or Zn; the liquid metal includes an auxiliary component, which includes any one or a combination of at least two of In, Bi, Cd, Cu, Ni, Hg, Pb, Cr, or Ce; the liquid metal is obtained from a solid metal by smelting or wet reduction. (2) The solid mixture obtained in step (1) is treated with sodium hydroxide solution and / or potassium hydroxide solution with a concentration of 0.1-10 mol / L to obtain carbon element and metal salt solution; The resulting metal salt solution was electrolyzed to obtain solid metal and oxygen deposited on the electrode.