Method and plant for continuous production of sponge iron from iron ore

Abstract

The invention relates to a plant for the continuous production of sponge iron from iron ore, said plant comprising a direct reduction shaft furnace (1) and means (24, 25, 26) for introducing a pressurized and heated hydrogen-rich reducing gas into the direct reduction shaft furnace (1) in order to reduce the iron ore in order to produce sponge iron, and a charging container (2) for charging the iron ore into the direct reduction shaft furnace (1), the charging container (2) has an inert gas inlet (8). The control unit (14) is configured to control the inert gas inlet valve (9) based on inputs from the reduction shaft furnace (1) pressure sensor (12) and the charge vessel pressure sensor (13) to provide a pressurized inert gas within the charge vessel (2) prior to discharging iron ore from the charge vessel (2) into the direct reduction shaft furnace (1), the gas inlet valve (9) is closed in such a way that the pressure of the inert gas in the charging container (2) is lower than or equal to the pressure in the direct reduction shaft furnace (1), and the gas inlet valve (9) is closed during the discharge of the iron ore from the charging container (2) into the direct reduction shaft furnace (1).

Description

Technical Field

[0001] The present invention relates to a method for continuously producing sponge iron from iron ore, the method comprising the steps of charging the iron ore into a direct reduction shaft furnace via a charging container, introducing a heated hydrogen-rich reducing gas into the direct reduction shaft furnace to reduce the iron ore to produce sponge iron, wherein a process pressure higher than atmospheric pressure is generated in the direct reduction shaft furnace, and removing the produced sponge iron from the direct reduction shaft furnace via a discharge container.

[0002] The present invention also relates to an apparatus for continuously producing sponge iron from iron ore, the apparatus comprising: a direct reduction shaft furnace; a device for introducing pressurized and heated hydrogen-rich reducing gas into the direct reduction shaft furnace to reduce the iron ore to produce sponge iron; a charging container for charging the iron ore into the direct reduction shaft furnace; and a discharge container for discharging the sponge iron from the direct reduction shaft furnace. Background Art

[0003] An apparatus for direct reduction (DR) of iron ore to sponge iron may use a charging container and a discharge container for charging the iron ore into a reduction shaft furnace and for discharging the sponge iron from the same shaft furnace. The iron ore is charged into the charging container, which is first flushed with an inert sealing gas to remove air from the container. The inert gas is pressurized to a pressure slightly greater than the operating pressure of the DR shaft furnace using the sealing gas. After pressurization, the valve separating the charging container and the DR shaft furnace is opened to allow the iron ore to be introduced into the shaft furnace together with the pressurized sealing gas. In order to prevent the reduction gas from penetrating into the charging container, the container is continuously flushed with a flow of sealing gas during the charging operation. After the ore is charged, the valve may be closed and the charging container may be opened to receive an additional charge of ore for charging. During the discharge of the sponge iron from the DR shaft furnace, a corresponding set of steps are taken for the discharge container.

[0004] Due to the overpressure of the sealing gas and the continuous flushing during charging, a large amount of sealing gas enters the DR shaft furnace and dilutes the reducing gas. Since the sealing gas is inert and accumulates in the reduction circuit, this leads to the need to surge the reducing gas, which is expensive (especially when the reducing gas is expensive electrolytic hydrogen).

[0005] Purpose of the Invention

[0006] An object of the present invention is to propose a method and an apparatus for direct reduction of iron ore to sponge iron which reduces the dilution of the reducing gas by the inert sealing gas compared to the prior art disclosed above. The method and the apparatus should be designed in such a way that the loss of sealing gas and reducing gas is minimized, thereby contributing to the efficient operation of the apparatus. Summary of the invention

[0007] The objects of the present invention are achieved by a method for continuously producing sponge iron from iron ore, the method comprising the following steps:

[0008] - charging the iron ore into the direct reduction shaft furnace via a charging container,

[0009] - introducing heated hydrogen-rich reducing gas into a direct reduction shaft furnace to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace, and

[0010] - removing the produced sponge iron from the direct reduction shaft furnace via a discharge container, wherein the charging step comprises the following steps:

[0011] - gas-tight closing of the iron ore outlet of the charging container with respect to the reduction shaft,

[0012] - charging the iron ore into the charging container via the iron ore inlet leading into the charging container,

[0013] - closing the iron ore inlet of the charging container gas-tightly with respect to the atmosphere,

[0014] - filling the charge container with an inert gas via an inert gas inlet into the charge container, and

[0015] - opening the iron ore outlet for discharging the iron ore from the charging container into the direct reduction shaft furnace, the method being characterized in that the step of filling the charging container with an inert gas comprises the step of measuring the process pressure in the direct reduction shaft furnace and filling the charging container with an inert gas until the pressure is equal to or lower than the process pressure in the direct reduction shaft furnace, and the method being characterized in that the inert gas inlet is closed during the opening of the iron ore outlet for discharging the iron ore from the charging container into the direct reduction shaft furnace.

[0016] According to one embodiment, the step of filling the charging container with an inert gas comprises filling the charging container with an inert gas until the pressure is less than 2 bar below the pressure in the direct reduction shaft furnace. In other words, when the discharge of the iron ore into the direct reduction shaft furnace begins, the pressure of the inert gas in the charging container differs from the pressure in the direct reduction shaft furnace by no more than 2 bar.

[0017] According to one embodiment, the step of filling the charging container with an inert gas comprises filling the charging container with an inert gas until the pressure is less than 1 bar below the pressure in the direct reduction shaft furnace. In other words, when the discharge of the iron ore into the direct reduction shaft furnace begins, the pressure of the inert gas in the charging container differs from the pressure in the direct reduction shaft furnace by no more than 1 bar.

[0018] According to one embodiment, after opening the iron ore outlet to discharge iron ore from the charging container into the direct reduction shaft furnace, the iron ore outlet is closed, followed by opening the gas outlet in the charging container and flushing the charging container with inert gas via the inert gas inlet and gas outlet of the charging container.

[0019] According to one embodiment, before the iron ore is charged into the charging vessel via the iron ore inlet, the pressure in the charging vessel is reduced to about atmospheric pressure.

[0020] According to one embodiment, the inert gas comprises mainly nitrogen.Thus, the present invention also prevents or reduces the formation of ammonia within the direct reduction chamber, since leakage of nitrogen into the direct reduction chamber is largely prevented.

[0021] According to one embodiment, the hydrogen-rich reducing gas introduced into the direct reduction shaft furnace comprises at least 80% by volume, preferably at least 90% by volume, of hydrogen (volume % determined under standard conditions of 1 atmosphere and 0° C.).

[0022] The objects of the present invention are also achieved by a method for the continuous production of sponge iron from iron ore, the method comprising the following steps:

[0023] - charging the iron ore into the direct reduction shaft furnace via a charging container,

[0024] - introducing heated hydrogen-rich reducing gas into a direct reduction shaft furnace to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace, and

[0025] - removing the produced sponge iron from the direct reduction shaft furnace via a discharge container,

[0026] The step of removing the sponge iron comprises the following steps:

[0027] - closing the sponge iron outlet of the discharge container gas-tightly with respect to the atmosphere,

[0028] - gas-tight closing of the sponge iron inlet from the direct reduction shaft furnace to the discharge vessel,

[0029] - filling the discharge container with an inert gas via an inert gas inlet into the discharge container,

[0030] - opening the sponge iron inlet and charging the sponge iron from the direct reduction shaft furnace into the discharge container via the sponge iron inlet,

[0031] - gas-tight closing of the sponge iron inlet of the discharge vessel with respect to the direct reduction shaft furnace, and

[0032] - opening the sponge iron outlet and discharging iron from the discharge container, the method being characterized in that the step of filling the discharge container with an inert gas comprises the step of measuring the process pressure in the direct reduction shaft furnace and filling the discharge container with an inert gas until the pressure is equal to or lower than the process pressure in the direct reduction shaft furnace, and the method being characterized in that the inert gas inlet is closed during the opening of the sponge iron inlet and the charging of sponge iron from the direct reduction shaft furnace into the discharge container.

[0033] According to one embodiment, the step of filling the discharge container with an inert gas comprises filling the discharge container with an inert gas until the pressure is less than 2 bar below the pressure in the direct reduction shaft furnace. In other words, when the sponge iron is started to be discharged from the direct reduction shaft furnace, the pressure of the inert gas in the discharge container is not more than 2 bar lower than the pressure in the direct reduction shaft furnace.

[0034] According to one embodiment, the step of filling the discharge container with an inert gas comprises filling the discharge container with an inert gas until the pressure is less than 1 bar below the pressure in the direct reduction shaft furnace. In other words, when the sponge iron is started to be discharged from the direct reduction shaft furnace, the pressure of the inert gas in the discharge container is not more than 1 bar lower than the pressure in the direct reduction shaft furnace.

[0035] According to one embodiment, before the sponge iron outlet is opened and the sponge iron is discharged from the discharge container, the discharge container is flushed with an inert gas via the inert gas inlet and the gas outlet of the discharge container.

[0036] According to one embodiment, the pressure in the discharge vessel is reduced to approximately atmospheric pressure before the sponge iron outlet is opened and the iron is discharged from the discharge vessel.

[0037] According to one embodiment, the inert gas comprises mainly nitrogen.Thus, the present invention also prevents or reduces the formation of ammonia within the direct reduction chamber, since leakage of nitrogen into the direct reduction chamber is largely prevented.

[0038] The objects of the present invention are also achieved by an apparatus for the continuous production of sponge iron from iron ore, the apparatus comprising:

[0039] - Direct reduction shaft furnace,

[0040] - an apparatus for introducing a pressurized, heated, hydrogen-rich reducing gas into a direct reduction shaft furnace for reducing iron ore to produce sponge iron,

[0041] - charging containers for charging iron ore into the direct reduction shaft furnace,

[0042] - a discharge container for discharging sponge iron from a direct reduction shaft furnace,

[0043] - an iron ore inlet for loading the iron ore into the charging container,

[0044] - an inlet valve arranged at the iron ore inlet and configured to hermetically close the iron ore inlet,

[0045] - an iron ore outlet for discharging iron ore from the charging vessel into the direct reduction shaft furnace,

[0046] - an outlet valve arranged at the iron ore outlet and configured to gas-tightly close the iron ore outlet,

[0047] - an inert gas source configured to provide pressurized inert gas to the charge vessel,

[0048] an inert gas inlet for introducing an inert gas into the charge container, the inert gas inlet having a gas inlet valve for controlling the flow of the inert gas into the charge container, and

[0049] a gas outlet for discharging gas from the charging container, the gas inlet having a gas outlet valve means for controlling the flow of gas out of the charging container, and

[0050] - a reduction shaft pressure sensor for measuring the gas pressure in a direct reduction shaft furnace, and

[0051] - a charging vessel pressure sensor for measuring the inert gas pressure in the charging vessel, the device being characterized in that the device comprises a control unit configured to control the gas inlet valve based on inputs from the reduction shaft furnace pressure sensor and the charging vessel pressure sensor to provide pressurized inert gas in the charging vessel before discharging the iron ore from the charging vessel into the direct reduction shaft furnace, so that the pressure of the inert gas in the charging vessel is lower than or equal to the pressure in the direct reduction shaft furnace, and to close the gas inlet valve during the discharging of the iron ore from the charging vessel into the direct reduction shaft furnace.

[0052] According to one embodiment, the control unit is configured to control the gas inlet valve based on inputs from the reduction shaft furnace pressure sensor and the charging vessel pressure sensor to provide pressurized inert gas in the charging vessel before discharging the iron ore from the charging vessel into the direct reduction shaft furnace, and to make the pressure of the inert gas in the charging vessel less than 2 bar lower than the pressure in the direct reduction shaft furnace.

[0053] According to one embodiment, the control unit is configured to control the gas inlet valve based on inputs from the reduction shaft furnace pressure sensor and the charging vessel pressure sensor to provide pressurized inert gas in the charging vessel before discharging the iron ore from the charging vessel into the direct reduction shaft furnace, and to make the pressure of the inert gas in the charging vessel less than 1 bar lower than the pressure in the direct reduction shaft furnace.

[0054] The objects of the present invention are also achieved by an apparatus for the continuous production of sponge iron from iron ore, the apparatus comprising:

[0055] - Direct reduction shaft furnace,

[0056] - an apparatus for introducing a pressurized, heated, hydrogen-rich reducing gas into a direct reduction shaft furnace for reducing iron ore to produce sponge iron,

[0057] - charging containers for charging iron ore into the direct reduction shaft furnace,

[0058] - a discharge container for discharging sponge iron from a direct reduction shaft furnace,

[0059] - a sponge iron inlet for loading the sponge iron into the discharge container,

[0060] - an inlet valve arranged at the sponge iron inlet and configured to close the sponge iron inlet airtightly,

[0061] - a sponge iron outlet for discharging the sponge iron from the discharge container,

[0062] - an outlet valve arranged at the sponge iron outlet and configured to close the sponge iron outlet in an airtight manner,

[0063] - an inert gas source configured to provide pressurized inert gas into the discharge vessel,

[0064] an inert gas inlet for introducing an inert gas into the discharge vessel, the inert gas inlet having a gas inlet valve for controlling the flow of the inert gas into the discharge vessel, and

[0065] a gas outlet for discharging gas from the discharge container, the gas outlet having a gas outlet valve for controlling the flow of gas out of the discharge container, and

[0066] - a reduction shaft pressure sensor for measuring the gas pressure in a direct reduction shaft furnace, and

[0067] - a discharge vessel pressure sensor for measuring the pressure of the inert gas in the discharge vessel, the device being characterized in that the device comprises a control unit configured to control a gas inlet valve of the discharge vessel based on inputs from the reduction shaft furnace pressure sensor and the discharge vessel pressure sensor to provide pressurized inert gas in the discharge vessel before charging the sponge iron into the discharge vessel so that the pressure of the inert gas in the discharge vessel is lower than or equal to the pressure in the direct reduction shaft furnace, and to close the gas inlet valve during charging of the sponge iron from the direct reduction shaft furnace into the discharge vessel.

[0068] According to one embodiment, the control unit is configured to control the gas inlet valve based on inputs from the reduction shaft furnace pressure sensor and the discharge vessel pressure sensor to provide pressurized inert gas in the discharge vessel before charging sponge iron from the direct reduction shaft furnace into the discharge vessel, so that the pressure of the inert gas in the discharge vessel is less than 2 bar lower than the pressure in the direct reduction shaft furnace.

[0069] According to one embodiment, the control unit is configured to control the gas inlet valve based on inputs from the reduction shaft furnace pressure sensor and the discharge vessel pressure sensor to provide pressurized inert gas in the discharge vessel before charging sponge iron from the direct reduction shaft furnace into the discharge vessel, and to make the pressure of the inert gas in the discharge vessel less than 1 bar lower than the pressure in the direct reduction shaft furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Will refer to Figure 1 Disclose embodiments of the present invention, Figure 1 A schematic illustration of a device according to the invention is shown. DETAILED DESCRIPTION

[0071] Figure 1 An embodiment of an apparatus for continuously producing sponge iron from iron ore is shown. The apparatus comprises: a direct reduction shaft furnace 1; means 24, 25, 26 for introducing pressurized and heated hydrogen-rich reducing gas into the direct reduction shaft furnace 1 to reduce iron ore to produce sponge iron; a charging container 2 for charging iron ore into the direct reduction shaft furnace 1; a feeding device 28 for feeding iron ore into the charging container 2; and a discharge container 3 for discharging sponge iron from the direct reduction shaft furnace 1. In addition, an iron ore inlet 4 for charging iron ore into the charging container 2 is provided; an inlet valve 5 arranged at the iron ore inlet 4 and configured to close the iron ore inlet 4 in an airtight manner; an iron ore outlet 6 for discharging iron ore from the charging container 2 into the direct reduction shaft furnace 1; an outlet valve 27 arranged at the iron ore outlet 6 and configured to close the iron ore outlet 6 in an airtight manner; an inert gas source 7 configured to provide pressurized inert gas into the charging container 2; an inert gas inlet 8 for introducing inert gas into the charging container 2, the inert gas inlet 8 having a gas inlet valve 9 for controlling the flow of inert gas into the charging container 2; a gas outlet 10 for discharging gas from the charging container 2, the gas outlet 10 having a gas outlet valve 11 device for controlling the flow of gas out of the charging container 2; and a reduction shaft furnace pressure sensor 12 for measuring the gas pressure in the direct reduction shaft furnace 1 and a charging container 2 pressure sensor 13 for measuring the inert gas pressure in the charging container 2.

[0072] The process 24, 25, 26 for introducing pressurized and heated hydrogen-rich reducing gas into the direct reduction shaft furnace 1 comprises: a hydrolyzer 24 for producing hydrogen; a heater 25 for heating the hydrogen before it is introduced into the direct reduction shaft furnace 1; and a process gas circulation loop having a treatment device for cleaning the exhaust gas from the direct reduction shaft furnace 1, etc., the exhaust gas is mixed with the hydrogen from the hydrolyzer 24 to form the hydrogen-rich reducing gas for direct reduction of iron ore into sponge iron. The hydrogen-rich reducing gas contains at least 90% by volume of hydrogen (volume % determined under standard conditions of 1 atmosphere and 0°C).

[0073] The apparatus for continuously producing sponge iron from iron ore further comprises a control unit 14 configured to control the gas inlet valve 9 based on inputs from the reduction shaft furnace 1 pressure sensor 12 and the charging container pressure sensor 13, so as to provide pressurized inert gas in the charging container 2 before discharging the iron ore from the charging container 2 into the direct reduction shaft furnace 1, so that the pressure of the inert gas in the charging container 2 is substantially equal to the pressure in the direct reduction shaft furnace 1, and to close the gas inlet valve 9 during the discharge of the iron ore from the charging container 2 into the direct reduction shaft furnace 1.

[0074] The apparatus for continuously producing sponge iron from iron ore further includes a sponge iron inlet 15 for charging sponge iron into a discharge container 3; an inlet valve 16 arranged at the sponge iron inlet 15 and configured to hermetically close the sponge iron inlet 15; a sponge iron outlet 17 for discharging sponge iron from the discharge container 3; and an outlet valve 18 arranged at the sponge iron outlet 17 and configured to hermetically close the sponge iron outlet 17. The inert gas source 7 is configured to provide pressurized inert gas into the discharge container 3. In addition, an inert gas inlet 19 for introducing inert gas into the discharge container 3 is provided, the inert gas inlet 19 having a gas inlet valve 20 for controlling the inert gas flowing into the discharge container 3; and a gas outlet 21 for discharging gas from the discharge container 3, the gas outlet 21 having a gas outlet valve 22 for controlling the gas flowing out of the discharge container 3. A discharge container pressure sensor 23 for measuring the inert gas pressure in the discharge container 3 is also provided.

[0075] The control unit 14 is configured to control the gas inlet valve 20 of the discharge container 3 based on inputs from the reduction shaft furnace pressure sensor 23 and the discharge container pressure sensor 23 to provide pressurized inert gas in the discharge container 3 before charging the sponge iron into the discharge container 3, so that the pressure of the inert gas in the discharge container 3 is approximately equal to the pressure in the direct reduction shaft furnace 1, and to close the gas inlet valve 20 during charging the sponge iron from the direct reduction shaft furnace 1 into the discharge container 3.

[0076] The iron ore inlet valve 5 , the iron ore outlet valve 27 , the sponge iron inlet valve 16 , and the sponge iron outlet valve 18 are control valves configured to be controlled by the control unit 14 .

[0077] The gas inlet valves 9 and 20 and the gas outlet valves 11 and 22 are control valves configured to be controlled by a control unit 14. The inert gas source 7 is configured to deliver an inert gas with an elevated pressure. Preferably, the inert gas mainly comprises nitrogen.

[0078] The plant for the continuous production of sponge iron from iron ore is configured to carry out the method according to the invention comprising the following sequential steps:

[0079] - charging the iron ore into the direct reduction shaft furnace 1 via the charging container 2,

[0080] - introducing heated hydrogen-rich reducing gas into the direct reduction shaft furnace 1 to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace 1, and

[0081] - removing the produced sponge iron from the direct reduction shaft furnace 1 via a discharge container 3,

[0082] - wherein the charging step comprises the following steps:

[0083] - gas-tight closing of the iron ore outlet 6 of the charging container 2 relative to the reduction shaft furnace 1,

[0084] - charging the charging container 2 with iron ore via the iron ore inlet 4 leading into the charging container 2,

[0085] - closing the iron ore inlet 4 of the charging container 2 gas-tightly with respect to the atmosphere,

[0086] - filling the charge container 2 with an inert gas via an inert gas inlet 8 into the charge container 2, and

[0087] - Opening the iron ore outlet 6 to discharge the iron ore from the charging vessel 2 into the direct reduction shaft furnace 1 .

[0088] The step of filling the charging container 2 with an inert gas comprises the steps of measuring the process pressure in the direct reduction shaft furnace 1 and filling the charging container 2 with an inert gas until the pressure is approximately equal to the process pressure in the direct reduction shaft furnace 1, wherein the inert gas inlet 8 is closed during the opening of the iron ore outlet 6 for discharging iron ore from the charging container 2 into the direct reduction shaft furnace 1.

[0089] After the iron ore outlet 6 is opened to discharge the iron ore from the charging container 2 into the direct reduction shaft furnace 1, the iron ore outlet 6 is closed, and then the gas outlet 10 in the charging container 2 is opened, and the charging container 2 is flushed with an inert gas via the inert gas inlet 8 and the gas outlet 10 of the charging container. Thus, before the iron ore is charged into the charging container 2 via the iron ore inlet 4 next time, the pressure in the charging container 2 is reduced to about atmospheric pressure.

[0090] The plant for continuous production of sponge iron from iron ore is also configured to carry out a method according to the invention comprising the following sequential steps:

[0091] - charging the iron ore into the direct reduction shaft furnace 1 via the charging container 2,

[0092] - introducing heated hydrogen-rich reducing gas into the direct reduction shaft furnace 1 to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace 1, and

[0093] - removing the produced sponge iron from the direct reduction shaft furnace 1 via the discharge container 3, wherein the step of removing the sponge iron comprises the following steps:

[0094] - closing the sponge iron outlet 17 of the discharge container 3 gas-tightly with respect to the atmosphere,

[0095] - gas-tightly closing the sponge iron inlet 15 from the direct reduction shaft furnace 1 to the discharge container 3,

[0096] - filling the discharge container 3 with an inert gas via the inert gas inlet 19 into the discharge container 3,

[0097] - opening the sponge iron inlet 15 and charging the sponge iron from the direct reduction shaft furnace 1 into the discharge container 3 via the sponge iron inlet 15,

[0098] - gas-tightly closing the sponge iron inlet 15 of the discharge vessel 3 relative to the direct reduction shaft furnace 1, and

[0099] - Open the sponge iron outlet 17 and discharge the sponge iron from the discharge container 3.

[0100] The step of filling the discharge container 3 with an inert gas comprises the steps of measuring the process pressure in the direct reduction shaft furnace 1 and filling the discharge container 3 with an inert gas until the pressure is approximately equal to the process pressure in the direct reduction shaft furnace 1, wherein the inert gas inlet 19 is closed during the opening of the sponge iron inlet 15 and the charging of sponge iron from the direct reduction shaft furnace 1 into the discharge container 3.

[0101] Before the sponge iron outlet 17 is opened and the sponge iron is discharged from the discharge container 3, the inert gas is flushed through the inert gas inlet 1 and the gas outlet 21 of the discharge container 3. Therefore, before the sponge iron outlet 17 is opened and the iron is discharged from the discharge container 3, the pressure in the discharge container 3 is reduced to about atmospheric pressure.

Claims

1. A method for continuously producing sponge iron from iron ore, comprising the steps of: - charging the iron ore into the direct reduction shaft furnace (1) via a charging container (2), - introducing heated hydrogen-rich reducing gas into the direct reduction shaft furnace (1) to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace (1), and - removing the produced sponge iron from the direct reduction shaft furnace (1) via a discharge container (3), - wherein the charging step comprises the following steps: - closing the iron ore outlet (6) of the charging container (2) in a gas-tight manner relative to the reduction shaft furnace (1), - charging the iron ore into the charging container (2) via an iron ore inlet (4) leading into the charging container (2), - closing the iron ore inlet (4) of the charging container (2) gas-tightly with respect to the atmosphere, - filling the charging container (2) with an inert gas via an inert gas inlet into the charging container (2), and - opening the iron ore outlet (6) to discharge iron ore from the charging container (2) into the direct reduction shaft furnace (1), the method being characterized in that the step of filling the charging container (2) with an inert gas comprises the step of measuring the process pressure in the direct reduction shaft furnace (1) and filling the charging container (2) with the inert gas until the pressure is equal to or lower than the process pressure in the direct reduction shaft furnace (1), and the method being characterized in that the inert gas inlet is closed during the opening of the iron ore outlet (6) to discharge iron ore from the charging container (2) into the direct reduction shaft furnace (1).

2. The method according to claim 1, wherein the step of filling the charging container (2) with an inert gas comprises filling the charging container (2) with an inert gas until the pressure is less than 2 bar below the pressure in the direct reduction shaft furnace (1).

3. The method according to claim 1, wherein the step of filling the charging container (2) with an inert gas comprises filling the charging container (2) with an inert gas until the pressure is less than 1 bar below the pressure in the direct reduction shaft furnace (1).

4. A method according to any preceding claim, wherein: After the iron ore outlet (6) is opened to discharge the iron ore from the charging container (2) into the direct reduction shaft furnace (1), the iron ore outlet (6) is closed, and then the gas outlet in the charging container (2) is opened, and the charging container (2) is flushed with inert gas via the inert gas inlet and the gas outlet (10) of the charging container.

5. The method according to any one of claims 1 to 4, wherein: Before the iron ore is charged into the charging container (2) via the iron ore inlet (4), the pressure in the charging container (2) is reduced to approximately atmospheric pressure.

6. A method for continuously producing sponge iron from iron ore, comprising the steps of: - charging the iron ore into the direct reduction shaft furnace (1) via a charging container (2), - introducing heated hydrogen-rich reducing gas into the direct reduction shaft furnace (1) to reduce the iron ore to produce sponge iron, wherein a process pressure above atmospheric pressure is generated in the direct reduction shaft furnace (1), and - removing the produced sponge iron from the direct reduction shaft furnace (1) via a discharge container (3), - wherein the step of removing the sponge iron comprises the following steps: - closing the sponge iron outlet (17) of the discharge container (3) gas-tightly with respect to the atmosphere, - gas-tightly closing the sponge iron inlet (15) from the direct reduction shaft furnace (1) to the discharge container (3), - filling the discharge container (3) with an inert gas via an inert gas inlet (19) into the discharge container (3), - opening the sponge iron inlet (15) so as to charge the sponge iron from the direct reduction shaft furnace (1) into the discharge container (3) via the sponge iron inlet (15), - closing the sponge iron inlet (15) of the discharge vessel (3) gas-tightly with respect to the direct reduction shaft furnace (1), and - opening the sponge iron outlet (17) to discharge iron from the discharge container (3), the method being characterized in that the step of filling the discharge container (3) with an inert gas comprises the step of measuring the process pressure in the direct reduction shaft furnace (1) and filling the discharge container (3) with the inert gas until the pressure is equal to or lower than the process pressure in the direct reduction shaft furnace (1), and the method being characterized in that the inert gas inlet (19) is closed during the opening of the sponge iron inlet (15) to charge the sponge iron from the direct reduction shaft furnace (1) into the discharge container (3).

7. The method according to claim 6, wherein the step of filling the discharge container (3) with an inert gas comprises filling the discharge container (3) with an inert gas until the pressure is less than 2 bar below the pressure in the direct reduction shaft furnace (1).

8. The method according to claim 6, wherein the step of filling the discharge container (3) with an inert gas comprises filling the discharge container (3) with an inert gas until the pressure is less than 1 bar below the pressure in the direct reduction shaft furnace (1).

9. The method according to any one of claims 6 to 8, wherein: Before the sponge iron outlet (17) is opened to discharge the sponge iron from the discharge container (3), an inert gas is flushed through the inert gas inlet (19) and the gas outlet (21) of the discharge container (3).

10. The method according to any one of claims 6 to 9, wherein: Before the sponge iron outlet (17) is opened and iron is discharged from the discharge container (3), the pressure in the discharge container (3) is reduced to approximately atmospheric pressure.

11. An apparatus for continuously producing sponge iron from iron ore, comprising: - a direct reduction shaft furnace (1), - means (24, 25, 26) for introducing pressurized heated hydrogen-rich reducing gas into the direct reduction shaft furnace (1) to reduce the iron ore to produce sponge iron, - a charging container (2) for charging iron ore into the direct reduction shaft furnace (1), - a discharge container (3) for discharging sponge iron from the direct reduction shaft furnace (1), - an iron ore inlet (4) for charging iron ore into the charging container (2), - an inlet valve (5) arranged at the iron ore inlet (4) and configured to close the iron ore inlet (4) in an airtight manner, - an iron ore outlet (6) for discharging iron ore from the charging container (2) into the direct reduction shaft furnace (1), - an outlet valve (27) arranged at the iron ore outlet (6) and configured to close the iron ore outlet (6) in an airtight manner, - an inert gas source (7) configured to provide pressurized inert gas into the charging container (2), an inert gas inlet (8) for introducing an inert gas into the charging container (2), the inert gas inlet (8) having a gas inlet valve (9) for controlling the flow of inert gas into the charging container (2), and a gas outlet (10) for discharging gas from the charging container (2), the gas outlet (10) having a gas outlet valve (11) means for controlling the flow of gas out of the charging container (2), and - a reduction shaft furnace pressure sensor (12) for measuring the gas pressure in the direct reduction shaft furnace (1), and - a charging container (2) pressure sensor (13) for measuring the pressure of the inert gas in the charging container (2), the device being characterized in that the device comprises a control unit (14) configured to control the gas inlet valve (9) based on inputs from the reduction shaft furnace (1) pressure sensor (12) and the charging container pressure sensor (13) to provide pressurized inert gas in the charging container (2) before discharging iron ore from the charging container (2) into the direct reduction shaft furnace (1) so that the pressure of the inert gas in the charging container (2) is lower than or equal to the pressure in the direct reduction shaft furnace (1), and to close the gas inlet valve (9) during the discharge of iron ore from the charging container (2) into the direct reduction shaft furnace (1).

12. The apparatus according to claim 11, wherein the control unit (14) is configured to control the gas inlet valve (9) based on inputs from the reduction shaft furnace pressure sensor (13) and the charging container pressure sensor (13) to provide pressurized inert gas in the charging container (2) before discharging iron ore from the charging container (2) into the direct reduction shaft furnace (1), and to make the pressure of the inert gas in the charging container (2) lower than the pressure in the direct reduction shaft furnace (1) by less than 2 bar.

13. The apparatus according to claim 11, wherein the control unit (14) is configured to control the gas inlet valve (9) based on inputs from the reduction shaft furnace pressure sensor (12) and the charging container pressure sensor (13) to provide pressurized inert gas in the charging container (2) before discharging iron ore from the charging container (2) into the direct reduction shaft furnace (1), and to make the pressure of the inert gas in the charging container (2) lower than the pressure in the direct reduction shaft furnace (1) by less than 1 bar.

14. An apparatus for continuously producing sponge iron from iron ore, comprising: - a direct reduction shaft furnace (1), - means (24, 25, 26) for introducing pressurized heated hydrogen-rich reducing gas into the direct reduction shaft furnace (1) to reduce the iron ore to produce sponge iron, - a charging container (2) for charging iron ore into the direct reduction shaft furnace (1), - a discharge container (3) for discharging sponge iron from the direct reduction shaft furnace (1), - a sponge iron inlet (15) for loading the sponge iron into the discharge container (3), - an inlet valve (16) arranged at the sponge iron inlet (15) and configured to close the sponge iron inlet (15) in an airtight manner, - a sponge iron outlet (17) for discharging the sponge iron from the discharge container (3), - an outlet valve (18) arranged at the sponge iron outlet (17) and configured to close the sponge iron outlet (17) in an airtight manner, - an inert gas source (7) configured to provide pressurized inert gas into the discharge container (3), an inert gas inlet (19) for introducing an inert gas into the discharge vessel (3), the inert gas inlet (19) having a gas inlet valve (20) for controlling the flow of inert gas into the discharge vessel (3), and a gas outlet (21) for discharging gas from the discharge container (3), the gas outlet (21) having a gas outlet valve (22) for controlling the flow of gas out of the discharge container (3), and - a reduction shaft furnace pressure sensor (12) for measuring the gas pressure in the direct reduction shaft furnace (1), and - a discharge vessel pressure sensor (23) for measuring the pressure of the inert gas in the discharge vessel (3), the device being characterized in that the device comprises a control unit (14), the control unit (14) being configured to control the gas inlet valve (20) of the discharge vessel (3) based on inputs from the reduction shaft furnace pressure sensor (23) and the discharge vessel pressure sensor (23), so as to provide pressurized inert gas in the discharge vessel (3) before charging sponge iron into the discharge vessel (3), so that the pressure of the inert gas in the discharge vessel (3) is lower than or equal to the pressure in the direct reduction shaft furnace (1), and to close the gas inlet valve (20) during charging of sponge iron from the direct reduction shaft furnace (1) into the discharge vessel (3).

15. The apparatus according to claim 14, wherein the control unit (14) is configured to control the gas inlet valve (20) based on inputs from the reduction shaft furnace pressure sensor (12) and the discharge vessel pressure sensor (23) to provide pressurized inert gas in the discharge vessel (3) before charging sponge iron from the direct reduction shaft furnace (1) into the discharge vessel (3), so that the pressure of the inert gas in the discharge vessel (3) is less than 2 bar lower than the pressure in the direct reduction shaft furnace (1).

16. The apparatus according to claim 14, wherein the control unit (14) is configured to control the gas inlet valve (20) based on inputs from the reduction shaft furnace pressure sensor (12) and the discharge container pressure sensor (23) to provide pressurized inert gas in the discharge container (3) before charging sponge iron from the direct reduction shaft furnace (1) into the discharge container (3), and to make the pressure of the inert gas in the discharge container (3) lower than the pressure in the direct reduction shaft furnace (1) by less than 1 bar.

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