A method for producing metal by hot ore thermal cycle, combustible converter gasification melting smelting

Abstract

The present application relates to a kind of with hot ore heat cycle, combustible converter gasification melting metal production method, belong to metal smelting field.The method is with hot ore as raw material, with combustible, with lime as slagging dephosphorization desulfurizer, to be made into mixture, the mixture is added in converter in batches, directly oxygen and carbon dioxide gasification melting smelting in furnace, to be made into metal liquid, reach the requirement of metal liquid, out of metal liquid, after refining, to be made into metal finished material.The method is energy saving and environmental protection, process flow is short, efficiency is high, energy consumption is low, cost is low, smelting scale is controllable, zero carbon emission.

Description

Technical Field

[0001] This invention relates to a method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting, belonging to the field of metal smelting. Background Technology

[0002] The traditional long-process technology for producing metallic iron and steel from iron ore involves the following steps: Iron ore is sintered to produce sinter, which is then cooled and processed into cold feed for the blast furnace. The blast furnace is charged with alternating layers of coke and sinter, and hot air and pulverized coal are used for blowing to melt the ore and produce molten iron. After slag removal, the molten iron is discharged. This molten iron then enters a converter for decarburization via oxygen blowing, and is smelted until it meets steelmaking requirements before being tapped. Finally, it is processed in a refining furnace to produce finished steel. The sintering energy consumption and fuel used are standard coal and pulverized coal, with a dosage of 100 kg of standard coal and pulverized coal per ton of molten iron.

[0003] The energy consumption of the blast furnace and the fuel consumption for blast furnace ironmaking are 500 kg of coke and pulverized coal per ton of molten iron (iron content of iron ore is 60%).

[0004] According to data released by the International Energy Agency (IEA) in 2019, the global steel industry emits as much as 2.6 billion tons of carbon dioxide annually, of which blast furnace ironmaking accounts for 67.02% of the carbon dioxide emissions.

[0005] CN200610085416.3 discloses a method for directly refining calcium carbide using iron slag, steel slag, or coal slag in a converter. The method is characterized by using iron slag, steel slag, or coal slag as the main raw material, supplemented with iron ore as a carbon stabilizer. It employs a converter top-blown steam, a bottom-blown steam, a mixture of gas, coal gas, or air and anthracite pulverized coal to produce calcium carbide liquid. The process steps are as follows: In the converter, iron ore is first added, followed by iron slag, steel slag, or coal slag. Steam is blown from the top of the converter to slag the material, and a mixture of steam, coal gas, or air and anthracite pulverized coal is blown from the bottom of the converter. The mixture is smelted for 20-25 minutes, and the temperature is raised to above 2000℃ to reduce and produce calcium carbide liquid. The weight proportions of each component in the converter are: 100 parts iron slag, steel slag, or coal slag, 5-8 parts iron ore, and 15-20 parts anthracite pulverized coal. This invention does not use an electric furnace, but instead uses iron slag, steel slag or coal slag to directly refine calcium carbide in a converter. Compared with the traditional electric furnace method of refining calcium carbide, this invention has lower investment and lower energy consumption.

[0006] CN200610088264.2 discloses a method for directly refining calcium carbide using coal slag, calcium carbide slag, or limestone in a converter. This method uses coal slag, calcium carbide slag, or limestone as the main raw material, supplemented with manganese ore, iron ore, or scrap steel as a carbon stabilizer. It employs a converter top-blowing method with steam or oxygen, and a bottom-blowing method with a mixture of steam, air, coal gas, acetylene, and pulverized coal to produce molten calcium carbide. The process steps are as follows: In the converter, manganese ore, iron ore, or scrap steel are first added, followed by coal slag, calcium carbide slag, or limestone. Steam or oxygen is blown from the top of the converter to slag, and a mixture of steam, air, coal gas, acetylene, and pulverized coal is blown from the bottom of the converter. The mixture is smelted for 20-25 minutes, and the temperature is raised to above 1600℃ to reduce and produce molten calcium carbide. This invention does not use an electric furnace; instead, it uses coal slag, calcium carbide slag, or limestone to directly refine calcium carbide in a converter. Compared with traditional electric furnace methods for refining calcium carbide, this invention requires less investment and consumes less energy.

[0007] CN200610088263.8 discloses a method for directly refining calcium carbide using liquid iron slag or steel slag in a converter. The method is characterized by using liquid iron slag or steel slag as the main material, supplemented with manganese ore, iron ore, or scrap steel as a carbon stabilizer. A mixture of steam or oxygen is blown from the top of the converter, and steam, air, coal gas, acetylene, and pulverized coal is blown from the bottom to produce molten calcium carbide. The process steps are as follows: In the converter, manganese ore, iron ore, or scrap steel is first added, followed by liquid iron slag or steel slag. Steam or oxygen is blown from the top of the converter to slag the slag, and a mixture of steam, air, coal gas, acetylene, and pulverized coal is blown from the bottom for 15-20 minutes, raising the temperature to above 2000℃ to reduce and produce molten calcium carbide. This invention does not use an electric furnace; instead, it uses liquid iron slag or steel slag to directly refine calcium carbide in a converter. Compared with traditional electric furnace methods, this invention requires less investment and consumes less energy.

[0008] CN200810020016.3 discloses a method for directly smelting ferrosilicon from silicon ore using a converter. This method uses silicon ore and scrap steel as main materials, supplemented with limestone and pulverized coal as auxiliary materials. It employs a method of blowing steam or oxygen from the top of the converter, and blowing a mixture of steam, oxygen, air, coal gas, acetylene, and pulverized coal from the sides or bottom of the converter to produce molten ferrosilicon. The process steps are as follows: In the converter, silicon ore and scrap steel are first added, followed by limestone and pulverized coal. Steam or oxygen is blown from the top of the converter to slag, and a mixture of steam, oxygen, coal gas, air, acetylene, and pulverized coal is blown from the sides or bottom of the converter for 20-25 minutes. The temperature is raised to above 1600℃ to reduce and produce molten ferrosilicon. The weight proportions of each component in the converter are: 100 parts silicon ore, 5-20 parts scrap steel, 5-8 parts limestone, and 20-25 parts pulverized coal. Compared with the traditional electric furnace method for smelting ferrosilicon, this method requires less investment and consumes less energy.

[0009] The flash ironmaking technology developed by Professor Zhang Wenhai, an academician of the Chinese Academy of Engineering, and his team consumes 351 kilograms of standard coal per ton of iron, improving energy efficiency by one-third.

[0010] Invention patent ZL2009100304379 describes a method for producing metals and hydrogen using a carbon dioxide thermal cycle. Its key feature is that the hydrogen can be used to generate electricity, and the smelting process is a negative energy consumption method for producing metals. Invention Patent ZL201010125994.1: A method for producing carbon-iron alloys using a thermal cycle of hydrogen, steam, and combustible materials. Features: A method for producing carbon-iron alloy metals with negative energy consumption. Excess hydrogen can be used to generate electricity.

[0011] CN202110570498.5 discloses a method for neutralizing carbon in steelmaking using iron ore, hydrogen, and oxygen.

[0012] In summary, each of the above smelting methods has its advantages and disadvantages. Essentially, there is currently no 100% perfect smelting method. Summary of the Invention

[0013] The purpose of this invention is to solve the problems mentioned in the background section by providing a method for smelting metals using hot ore thermal circulation and combustible material converter gasification and melting. This method is energy-saving and environmentally friendly, with a short process flow, high efficiency, low energy consumption, low cost, and controllable smelting scale. The smelting process is zero-emission, and the flue gas can be used for power generation. After power generation, the flue gas is recovered, and the separated carbon dioxide gas is recycled back to the converter for gasification, achieving multiple benefits.

[0014] The objective of this invention is achieved as follows: a method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting. Hot ore is used as the raw material, combined with combustible material as fuel, and lime as a slag-forming, dephosphorizing, and desulfurizing agent to form a mixture. This mixture is added to the converter in stages, where it is directly gasified and melted using oxygen and carbon dioxide to produce molten metal. Once the molten metal meets the requirements, it is refined to produce finished metal materials. The flue gas generated during converter gasification is subsequently used for power generation. After power generation, the flue gas is recovered, and carbon dioxide is separated and recycled back to the converter for further gasification.

[0015] The hot ore is made by forming raw pellets from ore, mineral powder and combustibles, and then sintering them in a sintering furnace at a temperature of 1200-1350℃.

[0016] The combustible material is biomass pellets.

[0017] The sintered hot ore material is completely sealed and kept at a temperature above 800℃, and then added to the converter in batches.

[0018] When the converter produces molten metal from each batch, 20-30% is retained. Combustible materials are added to increase carbon content, and then hot ore is added to repeat the smelting process.

[0019] The process steps of this method are as follows: First, a mixture of hot ore, combustibles and lime is added in batches at the charging port on the top of the converter. Oxygen is blown in through the oxygen lance on the top of the furnace. When the temperature inside the furnace reaches the point where molten metal appears, a mixture of oxygen and carbon dioxide is blown in for gasification and smelting. The smelting time is 25-40 minutes. The temperature rises to above 1650℃ to meet the requirements for tapping steel and molten metal. The molten metal is then tapped.

[0020] Metal smelting is carried out using an existing converter, which directly vaporizes and melts hot ore raw materials to produce molten metal. Once the molten metal meets the required standards, it is tapped. The primary objective is to deoxygenate and remove impurities from the ore raw materials.

[0021] The ore is either an iron alloy ore or an iron ore.

[0022] The ferroalloy ore is manganese iron ore, chromite ore, ferrosilicon ore, or nickel iron ore.

[0023] Compared with the prior art, the advantages of this invention are: This invention is an improvement on existing equipment and top-blown oxygen lance technology. The improved oxygen lance can blow combustible powder from the top, taking advantage of its strengths and overcoming its weaknesses, and innovatively replacing metal smelting methods such as blast furnaces.

[0024] Compared with blast furnace: 1) Converters can directly use hot ore for smelting, thus making up for the shortcomings of traditional smelting methods such as blast furnaces by utilizing the advantages of converters.

[0025] 2) Utilize biomass combustibles to replace coke and pulverized coal as an energy source.

[0026] 3) The converter can be started or stopped flexibly, and the operation is simple.

[0027] 4) The hot ore is melted into molten metal through a converter, which has high purity and zero carbon emissions, which is its biggest advantage.

[0028] 5) After the converter gasifies and smelts the metal, the flue gas can be continuously used for power generation.

[0029] 6) The flue gas after power generation is recovered, and the separated carbon dioxide is recycled back into the converter for gasification, replacing the air in the blast furnace. Implementation

[0030] Example 1: Steelmaking First, ore, mineral powder, and combustibles are pelletized into green pellets using a pelletizing machine. These pellets are then sintered in a sintering furnace at a temperature of 1200-1350℃. Next, the sintered hot ore, combustibles, and lime are mixed and fed into a converter in stages. Inside the converter, oxygen and carbon dioxide are used for direct gasification and melting to produce molten metal. The molten metal reaches a temperature above 1650℃ and is then refined to produce finished metal materials. The resulting flue gas is recycled for power generation. The carbon dioxide produced after power generation is also recycled.

[0031] The process steps of this method are as follows: First, a mixture of sintered hot ore, combustibles and lime is added in batches at the charging port on the top of the converter. Oxygen is blown in through the oxygen lance on the top of the furnace. When the temperature inside the furnace reaches the point where molten metal appears, a mixture of oxygen and carbon dioxide is blown in for gasification and smelting. The smelting time is 25-40 minutes. The temperature rises to above 1650℃ to meet the requirements for tapping steel and molten metal. The molten metal is then tapped.

[0032] Each converter has a capacity of 100 tons, and the capacity of the molten metal inside the furnace must be more than 130 tons. After 100 tons of steel are produced, the excess 30 tons of molten steel in the furnace are first added with a carbon raiser, because low-carbon molten steel is easy to carbonize. In this way, the 30 tons of molten steel are turned into molten iron. Then, hot ore of the same amount as 100 tons of molten steel is added continuously, and the smelting process is repeated.

[0033] Tests have shown that the steelmaking process using the technical solution of this embodiment, with each heat in the converter lasting 25-40 minutes, not only reduces carbon emissions but also improves the efficiency of converter steelmaking.

[0034] This innovative process uses natural iron ore instead of traditional molten iron and scrap steel as the main raw material, directly refining it into molten metal in a converter in one step.

[0035] Advantages of converters: By using a converter for smelting, hot ore is directly smelted into molten metal, which is then deoxygenated, impurities are removed, and flue gas is recycled for power generation.

[0036] 1680-1690 kg of iron ore can be smelted into 1 ton of steel. Using biomass as combustible material, the sintering consumption is 100 kg of standard coal. Assuming a blast furnace consumes 500 kg of standard coal per ton of molten iron, biomass replaces 250 kg of standard coal, and the oxygen content is within 60 m³. The amount of CO2 recycled per ton of steel is over 300 m³. After smelting, approximately 500-600 m³ of CO can be recovered per ton of steel. 500 m³ × 3000 kcal = 1,500,000 kcal. 1,500,000 kcal ÷ 230 kcal = 650 kWh of electricity. That is, the flue gas from each ton of steel can generate 650 kWh of electricity. Subtracting the 60 kWh used for oxygen production, the net power generation is 590 kWh.

[0037] Comparative Example 1: In conventional converter steelmaking (steelmaking using molten iron), the carbon content of each ton of molten iron exceeds 35 kg, and about 60 cubic meters of oxygen are required to smelt each ton of steel. After each ton of steel is smelted, 150 cubic meters of coal gas can be recovered.

[0038] Comparative Example 2: Blast Furnace Ironmaking Iron ore powder contains 60% iron. 1670 kg of ore powder can be smelted into 1 ton of molten iron. Each ton of molten iron requires 100 kg of pulverized coal for sintering, and 500 kg of coke and pulverized coal are used in the blast furnace, for a total of 600 kg.

[0039] Each ton of molten iron produced in a blast furnace requires 1,400 cubic meters of air, and the blast furnace flue gas can be recovered, averaging 1,900 cubic meters.

[0040] The flue gas per ton of molten iron contains 25.77% CO, 16.29% CO2, 57.03% N2, 0.09% H2, and 0.01% CH4.

[0041] CO2: 16.29% × 1900 = 310 cubic meters, CO: 25.77% × 1900 = 490 cubic meters, totaling 800 cubic meters of oxygen.

[0042] N2: 57.03% × 1900 = 1100 cubic meters.

[0043] 1400 cubic meters of air, including 1100 cubic meters of nitrogen and 300 cubic meters of oxygen.

[0044] 800 - 300 = 500 cubic meters of oxygen.

[0045] 1670 kg of iron ore sinter can produce 500 cubic meters of oxygen.

[0046] Compared to other metal smelting furnaces, converters offer advantages such as greater process flexibility, higher performance, and easier temperature control. They reduce heat loss and increase recovery rates, thereby lowering energy consumption. As a result, while increasing production capacity, the flue gas can be continuously used for power generation. After power generation, the flue gas is recovered and separated to remove carbon dioxide, which is then recycled. This significantly reduces costs.

[0047] Example 2: Iron alloy making The preparation method is the same as in Example 1, except that the raw material ore powder is different. The ferroalloy ore used is manganese iron ore, chromite ore, ferrosilicon ore, and nickel iron ore.

[0048] Experimental progress: In the latter half of 1979, a crucible was made from discarded electrodes, with a capacity to gasify and melt 10-20 kg of molten iron. This was subsequently modified into a small converter, and experimental research was conducted at a sheet metal factory site outside the steel plant. Through hands-on experiments using oxygen and an oxygen lance in conjunction with the crucible, using scrap iron, limestone, and anthracite powder as raw materials, success was finally achieved after continuous experimentation. The first stage successfully produced calcium carbide. The second stage used iron oxide slag and iron oxide produced from oxygen cutting of steel plates as raw materials, adding limestone and anthracite powder, and gasifying and melting them under the influence of oxygen and an oxygen lance to obtain molten metal. The third stage used iron ore as raw material, adding limestone and anthracite powder, and gasifying and melting them under the influence of oxygen and an oxygen lance to obtain molten metal. The fourth stage used scale and waste produced from blacksmithing and steel rolling as raw materials, adding limestone and anthracite powder, and gasifying and melting them under the influence of oxygen and an oxygen lance to obtain molten metal. In the fifth stage, ferroalloy ore is used as raw material, and limestone and anthracite powder are added. The mixture is then gasified and smelted under the action of oxygen and an oxygen lance to obtain molten metal.

[0049] The above experiments and studies were conducted intermittently, and then alloys and other metals were smelted.

[0050] In 1981, an experiment was conducted in a 3-ton electric arc furnace, adding iron oxide scale from the rolling mill to the scrap steel to replace a portion of it. The first furnace added 10% iron oxide scale, the second 15%, the third 20%, the fourth 25%, and the fifth 30%. Before adding iron oxide scale, the average electricity consumption per ton of steel was over 900 kWh. After adding 30% scrap steel equivalent of iron oxide scale, the electricity consumption per ton of steel decreased to approximately 750 kWh, a reduction of over 150 kWh per ton. The reason for this was that, compared to the same weight of scrap steel, iron oxide scale had a smaller volume. Before adding iron oxide scale, four bags of material were needed per furnace; after adding it, only three bags were required. Ultimately, this shortened the smelting time per furnace, reduced electricity consumption, and lowered costs.

[0051] In 1993, more than a dozen intermittent experimental studies were conducted outside the factory, with a capacity of 100-200 kg; in 2005, the capacity reached 600-1000 kg.

Claims

1. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting smelting, characterized in that: The method uses hot ore as raw material, combustible material as fuel, and lime as slag-forming, dephosphorizing, and desulfurizing agent to form a mixture. The mixture is added to a converter in several batches, where it is directly gasified, melted, and smelted with oxygen and carbon dioxide to produce molten metal. Once the molten metal meets the requirements, it is refined to produce finished metal materials.

2. The method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 1, characterized in that: The hot ore is made from ore, mineral powder and combustibles into raw pellets, which are then sintered in a sintering furnace at a temperature of 1200-1350℃.

3. The method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 1, characterized in that: The combustible material is biomass pellets.

4. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 2, characterized in that: The sintered hot ore material is sealed and kept at a temperature above 800℃, and then added to the converter in batches.

5. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 4, characterized in that: The flue gas produced by converter gasification is used for power generation.

6. The method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 1, characterized in that: The molten metal is discharged when the temperature reaches 1650℃ or above.

7. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 2, characterized in that, When the converter produces molten metal from each batch, 20-30% is retained. Combustible materials are added to increase carbon content, and then hot ore is added to repeat the smelting process.

8. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 2, characterized in that, The process steps of this method are as follows: First, a mixture of hot ore, combustibles and lime is added in batches at the charging port on the top of the converter. Oxygen is blown in through the oxygen lance on the top of the furnace. When the temperature inside the furnace reaches the point where molten metal appears, a mixture of oxygen and carbon dioxide is blown in for gasification and smelting. The smelting time is 25-40 minutes. The temperature rises to above 1650℃ to meet the requirements for tapping steel and molten metal. The molten metal is then tapped.

9. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 1, characterized in that: The ore is either an iron alloy ore or an iron ore.

10. A method for producing metals using hot ore thermal circulation and combustible material converter gasification and melting as described in claim 9, characterized in that: The ferroalloy ore is manganese iron ore, chromite ore, ferrosilicon ore, or nickel iron ore.