Low temperature ironmaking process

Abstract

The application discloses a low-temperature iron smelting method, wherein the low-temperature iron smelting method comprises the following steps: putting an iron-containing raw material and a carbon-containing reducing agent into a chloride molten salt, so that the raw material is firstly dissolved in the chloride and then reduced by the reducing agent. The raw material is firstly dissolved in the chloride and then reduced by the reducing agent, and the required reaction temperature is greatly reduced, so that the energy consumption can be significantly reduced. Moreover, the low-temperature iron smelting method has higher carbon utilization efficiency, and the generated gas is carbon dioxide which can be directly discharged.

Description

Technical Field

[0001] This application relates to the field of metallurgy, and more specifically, to a method for low-temperature ironmaking. Background Technology

[0002] In existing technologies, the main raw materials for ironmaking are iron ore, coke, limestone, and air. Among them, iron ore is the main raw material for ironmaking, coke is used as a reducing agent in the ironmaking process, and limestone is mainly used to lower the melting point of gangue.

[0003] In the ironmaking process, these raw materials undergo physicochemical reactions in a specific atmosphere to obtain reduced pig iron. The main reaction in ironmaking is that, at high temperatures, carbon in the coke and injected materials, along with carbon monoxide generated from the combustion of carbon, removes oxygen from the iron ore to obtain iron. Typically, the reaction temperature is between 1000 and 1300°C, which is relatively high and consumes a significant amount of energy. Furthermore, the flue gas produced by the reaction, including carbon monoxide, cannot be directly emitted and must be extracted from the top of the furnace for recovery or treatment.

[0004] Therefore, how to reduce energy consumption and simplify gas emissions has become the technical problem that this application needs to solve. Summary of the Invention

[0005] In view of this, this application proposes a low-temperature ironmaking method to reduce energy consumption and simplify gas emissions.

[0006] This application provides a low-temperature ironmaking method, wherein the low-temperature ironmaking method includes adding iron-containing raw materials and carbon-containing reducing agents into a molten salt of chloride, so that the raw materials are first dissolved in the chloride and then reduced by the reducing agent.

[0007] Optionally, the chloride includes at least one of NaCl, KCl, MgCl2, CaCl2, and BaCl2.

[0008] Optionally, the raw materials include iron ore and / or iron-containing solid waste.

[0009] Optionally, the reducing agent includes at least one of coke, waste graphite material, and carbonaceous organic solid waste with a water content of less than 5%.

[0010] Optionally, the raw materials and reducing agents are in powder form, and the size of the raw materials and reducing agents is less than 5 mm.

[0011] Optionally, the low-temperature ironmaking method includes: first mixing the raw materials and reducing agent and then adding them to the chloride, wherein the molar ratio of the raw materials and reducing agent is 0.5-2.0.

[0012] Optionally, the temperature of the chloride is 800℃-1200℃.

[0013] Optionally, the low-temperature ironmaking method includes adding the raw materials and reducing agent to the chloride using a carrier gas.

[0014] Optionally, the low-temperature ironmaking method includes adding an oxide to the chloride to promote the reaction.

[0015] Optionally, the oxide includes at least one of Na₂O, K₂O, MgO, CaO, and BaO; and / or, the concentration of the oxide is 5 mol% to 25 mol%.

[0016] According to the technical solution of this application, the raw materials are first dissolved in chloride and then reduced by a reducing agent, which greatly reduces the required reaction temperature and thus significantly reduces energy consumption. Furthermore, the low-temperature ironmaking method of this application achieves higher carbon utilization efficiency, and the generated gas is carbon dioxide, which can be directly emitted.

[0017] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application, and the illustrative embodiments and descriptions thereof are used to explain this application. In the drawings:

[0019] Figure 1 A schematic diagram of one embodiment of an ironmaking apparatus used in the low-temperature ironmaking method according to this application;

[0020] Figure 2 This is a schematic diagram of another embodiment of the ironmaking equipment used in the low-temperature ironmaking method according to this application;

[0021] Figure 3 The product is the metallic iron granules obtained in Example 1. Detailed Implementation

[0022] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] This application provides a low-temperature ironmaking method, wherein the low-temperature ironmaking method includes adding iron-containing raw materials and carbon-containing reducing agents into a molten salt of chloride, so that the raw materials are first dissolved in the chloride and then reduced by the reducing agent.

[0024] The low-temperature ironmaking method of this application involves first reacting the raw materials dissolved in chlorides with a reducing agent, which significantly reduces the required reaction temperature and thus substantially lowers energy consumption. Furthermore, the low-temperature ironmaking method of this application achieves higher carbon utilization efficiency, and the generated gas is carbon dioxide, which can be directly emitted.

[0025] Specifically, when raw materials and reducing agents are added to the molten salt of chloride, the raw materials first come into contact with and dissolve in the chloride, forming iron ions that can move freely within the molten salt. These iron ions then come into full contact with the reducing agent and undergo a reduction reaction. Therefore, in the method of this application, the freely moving iron ions can promote the kinetics of the low-temperature reaction, thereby reducing the reaction temperature. Furthermore, using the low-temperature ironmaking method of this application, a solid iron product is ultimately obtained, rather than molten iron as in traditional methods, which facilitates collection and transfer to subsequent processes.

[0026] Furthermore, existing technologies involve high reaction temperatures, resulting in exhaust gases that are primarily carbon monoxide. In contrast, the method of this application involves lower reaction temperatures, producing exhaust gases that are primarily carbon dioxide, which can be directly emitted or require only simple treatment before emission, significantly simplifying exhaust gas emission treatment.

[0027] The chloride can be of an appropriate type to form a molten salt and dissolve the raw material to form iron ions. Specifically, the chloride may include at least one of NaCl, KCl, MgCl2, CaCl2, and BaCl2. It is understood that the method of this application uses chloride molten salt, which has the advantages of being inexpensive, safe, and having a low melting point.

[0028] In this application, the raw materials can be suitable iron-containing materials. Specifically, the raw materials may include iron ore and / or iron-containing solid waste. The iron-containing solid waste may be in a suitable form, such as steel slag, red mud, etc.

[0029] In addition, the reducing agent can be of an appropriate type. For example, a carbon-containing reducing agent can be used. Specifically, the reducing agent may include at least one of coke, waste graphite material, and carbon-containing organic solid waste with a water content of less than 5%. Carbon-containing organic solid waste may include, for example, waste plastics, wood, biomass, etc.

[0030] In this application, the reducing agent and raw materials can be in a suitable solid form. For example, the raw materials and reducing agent can be in powder form. To facilitate the reaction and improve reaction efficiency, small-particle powder raw materials and reducing agents can be used; preferably, the size of the raw materials and reducing agents is less than 5 mm.

[0031] Raw materials and reducing agents can be added separately. However, to facilitate addition and control of the reaction process, they can be added together. Specifically, the low-temperature ironmaking method may include: first mixing the raw materials and reducing agent before adding them to the chloride. The raw materials and reducing agent can be mixed in a predetermined ratio to meet the reaction requirements and obtain appropriate reaction efficiency. Preferably, the molar ratio of the raw materials and reducing agent can be 0.5-2.0.

[0032] Furthermore, the raw materials and reducing agents can be added in an appropriate manner, such as directly above the molten chloride salt, or by using a carrier gas to add them to the chloride. When using a carrier gas, it can be any suitable gas that does not react with the molten salt, raw materials, or reducing agent, such as nitrogen or an inert gas (e.g., argon). By blowing the raw materials with the carrier gas, the raw materials and reducing agents can be pushed into the molten salt to ensure sufficient contact, and the carrier gas can also agitate the molten salt, making its internal composition more homogeneous, thereby improving reaction efficiency. The flow rate of the carrier gas can be selected as needed, for example, from 0.5 L / min to 2 L / min.

[0033] The raw materials and chlorides can be in appropriate proportions to meet the needs of reaction and continuous production. For example, the molar ratio of raw materials to chlorides can be 1:10 to 1:5.

[0034] As described above, the method of this application can dissolve iron oxide in the raw material into iron ions using molten chloride salt, therefore it is necessary to maintain the molten chloride salt state throughout the process. For this purpose, the temperature of the chloride can be maintained at 800℃-1200℃.

[0035] Furthermore, to promote the reaction, the low-temperature ironmaking method may include adding an oxide to the chloride to accelerate the reaction. The oxide can be of an appropriate type, such as an alkali metal or alkaline earth metal oxide that is soluble in chloride. Preferably, the oxide may include at least one of Na₂O, K₂O, MgO, CaO, and BaO. The amount of oxide added can be adjusted according to the type and amount of raw materials and reducing agents to ensure accelerated reaction while avoiding side effects. Preferably, the concentration of the oxide is 5 mol%-25 mol%.

[0036] The method described in this application can be implemented using suitable equipment. For example, it can be implemented using... Figure 1 and Figure 2 The ironmaking equipment shown is iron smelting equipment. Iron smelting equipment can be configured to have… Figure 1 Vertical furnace body 10 or Figure 2 The inclined furnace body 20 allows raw materials and reducing agents to be fed from the feeding port 30 above the liquid surface or the side below the liquid surface (using carrier gas). Exhaust gas (carbon dioxide) can be discharged from the exhaust port 40 at the top. The iron products (solid iron particles) produced by reduction can be discharged from the discharge port 50 at the bottom and collected in the material tank 60.

[0037] The low-temperature ironmaking method of this application is described below with reference to specific embodiments.

[0038] Example 1

[0039] In the low-temperature ironmaking method of this application, the raw material is iron ore particles with a size of 3 mm, and the reducing agent is coke particles with a size of 3 mm. The chloride is pure NaCl.

[0040] The chloride molten salt was heated to 800℃, and raw materials, reducing agent, and oxide (Na2O, concentration 5 mol%) were added. The molar ratio of raw materials to reducing agent was 0.5, and the ratio of raw materials to chloride was 0.1.

[0041] The chemical reactions that occur in sequence are:

[0042] Fe2O3(s)+6NaCl(l)→3Na2O(l)+2FeCl3(l)

[0043] 1.5C(s)+3Na2O(l)+2FeCl3(l)→1.5CO2(g)+2Fe(s)+6NaCl(l).

[0044] The overall reaction is: 1.5C(s) + Fe₂O₃(s) → 1.5CO₂(g) + 2Fe(s)

[0045] The reaction products were washed with water and magnetically separated to obtain solid metallic iron particles, such as... Figure 3 As shown, this product can be used directly in electric arc furnace steelmaking.

[0046] Example 2

[0047] The low-temperature ironmaking method of Example 1 was adopted, wherein the oxide was K2O with a concentration of 10 mol%.

[0048] The chloride molten salt is heated to 900°C, and then the raw materials, reducing agent, and oxide are added. The molar ratio of raw materials to reducing agent is 0.5, and the ratio of raw materials to chloride is 0.1.

[0049] The chemical reactions that occur in sequence are:

[0050] Fe2O3(s)+6KCl(l)→3K2O(l)+2FeCl3(l)

[0051] 1.5C(s)+3K2O(l)+2FeCl3(l)→1.5CO2(g)+2Fe(s)+6KCl(l).

[0052] The overall reaction is: 1.5C(s) + Fe₂O₃(s) → 1.5CO₂(g) + 2Fe(s)

[0053] Example 3

[0054] The low-temperature ironmaking method of Example 1 was used, wherein the oxide was CaO with a concentration of 25 mol%. The chloride molten salt was heated to 1000°C, and the raw materials, reducing agent, and oxide were added. The molar ratio of raw materials to reducing agent was 0.5, and the ratio of raw materials to chloride was 0.1.

[0055] The chemical reactions that occur in sequence are:

[0056] Fe2O3(s)+3CaCl2(l)→3CaO(l)+2FeCl3(l)

[0057] 1.5C(s)+3CaO(l)+2FeCl3(l)→1.5CO2(g)+2Fe(s)+3CaCl2(l).

[0058] The overall reaction is: 1.5C(s) + Fe₂O₃(s) → 1.5CO₂(g) + 2Fe(s)

[0059] Example 4

[0060] The low-temperature ironmaking method of Example 1 was adopted, wherein the raw material was steel slag particles with a size of 3 mm and the reducing agent was waste graphite particles.

[0061] The chloride molten salt is heated to 1000℃, and raw materials and reducing agents are added. The molar ratio of raw materials to reducing agents is 1.5, and the ratio of raw materials to chloride is 0.2. The resulting solid iron product can be used for converter steelmaking.

[0062] Example 5

[0063] The low-temperature ironmaking method of Example 1 was adopted, wherein the chloride was 80 mol% CaCl2-20 mol% MgCl2.

[0064] The chloride molten salt is heated to 900°C, and then the raw materials and reducing agent are added. The molar ratio of the raw materials to the reducing agent is 2.

[0065] The chemical reactions that occur in sequence are:

[0066] Fe2O3(s)+3MgCl2(l)→3MgO(l)+2FeCl3(l)

[0067] Fe2O3(s)+3CaCl2(l)→3CaO(l)+2FeCl3(l)

[0068] 1.5C(s)+3CaO(l)+2FeCl3(l)→1.5CO2(g)+2Fe(s)+3CaCl2(l).

[0069] 1.5C(s)+3MgO(l)+2FeCl3(l)→1.5CO2(g)+2Fe(s)+3MgCl2(l).

[0070] The overall reaction is: 1.5C(s) + Fe₂O₃(s) → 1.5CO₂(g) + 2Fe(s)

[0071] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0072] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0073] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A low-temperature ironmaking method, characterized in that, The low-temperature ironmaking method includes adding iron-containing raw materials, carbon-containing reducing agents, and oxides for promoting the reaction into a molten salt of chloride, so that the raw materials are first dissolved in the chloride and then reduced by the reducing agent; The temperature of the chloride is 800℃-1000℃; The oxide includes at least one of Na2O, K2O, MgO, CaO, and BaO; The concentration of the oxide is 5 mol%-25 mol%; The products generated by the low-temperature ironmaking method are solid iron and carbon dioxide.

2. The low-temperature ironmaking method according to claim 1, characterized in that, The chloride includes at least one of NaCl, KCl, MgCl2, CaCl2, and BaCl2.

3. The low-temperature ironmaking method according to claim 1, characterized in that, The raw materials include iron ore and / or iron-containing solid waste.

4. The low-temperature ironmaking method according to claim 1, characterized in that, The reducing agent includes at least one of coke, waste graphite material, and carbonaceous organic solid waste with a water content of less than 5%.

5. The low-temperature ironmaking method according to claim 1, characterized in that, The raw materials and reducing agents are in powder form, and the size of the raw materials and reducing agents is less than 5 mm.

6. The low-temperature ironmaking method according to claim 5, characterized in that, The low-temperature ironmaking method includes: first mixing the raw materials and reducing agent and then adding them to the chloride, wherein the molar ratio of the raw materials and reducing agent is 0.5-2.

0.

7. The low-temperature ironmaking method according to claim 1, characterized in that, The low-temperature ironmaking method includes adding the raw materials and reducing agent to the chloride using a carrier gas.

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